Objective To investigate the changing antimicrobial resistance profiles of Streptococcus pneumoniae isolates from children in Chongqing area from 2011 to 2022, and to provide evidence for rational use of antibiotics and prevention of nosocomial infections. Methods The clinical data of S. pneumoniae strains isolated from pediatric patients during 2011-2022 were retrospectively analyzed. Antimicrobial susceptibility testing was performed with commercial automated systems and E-test. The results were interpreted according to the breakpoints in CLSI document (2022 edition). Results A total of 26 668 strains of S. pneumoniae were isolated during the 12-year period. The proportion of S. pneumoniae was 16.0% in the total pathogenic bacterial isolates and 46.4% in all the gram-positive bacterial pathogens. S. pneumoniae strains were mainly isolated from respiratory specimens (97.1%), followed by blood samples (1.5%). The highest proportion of S. pneumoniae isolates was in infants (38.2%), followed by toddlers (32.4%), preschool age (22.9%), school age (5.6%), adolescents (0.6%) and neonates (0.4%). All of the 38 strains of nonmeningitis S. pneumoniae (0.1%) isolated from cerebrospinal fluid were resistant to penicillin. Overall, 35.7% and 32.4% of these strains were resistant to cefotaxime and meropenem, respectively. The majority of S. pneumoniae (99.9%, 26 630/26 668) were nonmeningitis isolates. The prevalence of penicillin-susceptible (PSSP), -intermediate (PISP), and-resistant (PRSP) strains was 71.9% (16 083), 25.1% (5 610), and 3.0% (674), respectively. The prevalence of PRSP in infants and preschool children was higher than that in other age groups. The nonmeningitis S. pneumoniae isolates showed higher than 95% resistance rate to erythromycin, clindamycin and tetracycline, but 0.2%, 0.2% and 0.1% resistance rate to levofloxacin, moxifloxacin and rifampicin, respectively. No S. pneumoniae strains were found resistant to vancomycin or linezolid. Conclusions The proportion and antimicrobial resistance profiles of S. pneumoniae strains isolated from pediatric patients varied with age group and specimen type. The decreasing prevalence of PRSP may inform empirical treatment of S. pneumoniae infections in children in Chongqing area.

Objective To investigate the changing antibiotic resistance profiles of E. coli isolated from patients in the 52 hospitals participating in the CHINET program from 2015 to 2021. Methods Antimicrobial susceptibility was tested for clinical isolates of E. coli according to the unified protocol of CHINET program. WHONET 5.6 and SPSS 20.0 software were used for data analysis. Results A total of 289 760 nonduplicate clinical strains of E. coli were isolated from 2015 to 2021, mainly from urine samples (44.7 ±3.2)%. The proportion of E. coli strains isolated from urine samples was higher in females than in males (59.0% vs 29.5%). The proportion of E. coli strains isolated from respiratory tract and cerebrospinal fluid samples was significantly higher in children than in adults (16.7% vs 7.8%, 0.8% vs 0.1%, both P < 0.05). The isolates from internal medicine department accounted for the largest proportion (28.9 ± 2.8)% with an increasing trend over years. Overall, the prevalence of ESBLs-producing E. coli and carbapenem resistant E. coli (CREco) was 55.9% and 1.8%, respectively during the 7-year period. The prevalence of ESBLs-producing E. coli was the highest in tertiary hospitals each year from 2015 to 2021 compared to secondary hospitals. The prevalence of CREco was higher in children's hospitals compared to secondary and tertiary hospitals each year from 2015 to 2021. The prevalence of ESBLs-producing E. coli in tertiary hospitals and children’s hospitals and the prevalence of CREco in children's hospitals showed a decreasing trend over the 7-year period. The prevalence of CREco in secondary and tertiary hospitals increased slowly. Antibiotic resistance rates changed slowly from 2015 to 2021. Carbapenem drugs (imipenem, meropenem) were the most active drugs among β-lactams against E. coli (resistance rate ≤ 2.1%). The resistance rates of E. coli to β-lactam/β-lactam inhibitor combinations (piperacillin-tazobactam, cefoperazone-sulbactam), aminoglycosides (amikacin), nitrofurantoin and fosfomycin (for urinary isolates only) were all less than 10%. The resistance rate of E. coli strains to antibiotics varied with the level of hospitals and the departments where the strains were isolated, especially for cefazolin and ciprofloxacin, to which the resistance rate of E. coli strains from children in non-ICU departments was significantly lower than that of the strains isolated from other departments (P < 0.05). The E. coli isolates from ICU showed higher resistance rate to most antimicrobial agents tested (excluding tigecycline) than the strains isolated from other departments. The E. coli strains isolated from tertiary hospitals showed higher resistance rates to the antimicrobial agents tested (excluding tigecycline, polymyxin B, cefepime and carbapenems) than the strains from secondary hospitals and children's hospitals. Conclusions E. coli is an important pathogen causing clinical infection. More than half of the clinical isolates produced ESBL. The prevalence of CREco is increasing in secondary and tertiary hospitals over the 7-year period even though the overall prevalence is still low. This is an issue of concern.

Objective To investigate the antimicrobial resistance patterns of carbapenem-resistant Klebsiella pneumoniae (CRKP) strains isolated from children for better prevention, treatment, and control of CRKP infections in children. Methods A total of 182 clinical CRKP strains were collected between January 2018 and December 2020 in Hebei Children's Hospital. All CRKP strains were identified by matrix-assisted laser desorption ionization - time of flight (MALDI-TOF) mass spectrometry. The common carbapenemase genes (bla_KPC, bla_NDM, bla_IMP, bla_VIM, bla_OXA-48) of CRKP isolates were studied by PCR. Multilocus sequence typing (MLST) was performed for homology analysis. Results The 182 children infected with CRKP were mainly infants (>28 days to <1 years), accounting for 49.45% (90/182), followed by newborns (≤28 days), accounting for 36.26% (66/182). The main source of the 182 CRKP isolates was sputum (50.55%, 92/182), blood (15.93%, 29/182), and urine (13.19%, 24/182). The strains were mainly isolated from patients in neonatology (30.22%, 55/182), general surgery (21.43%, 39/182), cardiac surgery (13.19%, 24/182), and intensive care unit (11.54%, 21/182). Antimicrobial susceptibility testing showed that all of the 182 CRKP strains were resistant to cefepime, ceftazidime, piperacillin-tazobactam, and cefoperazone-sulbactam (100%). Overall, 97.8%, 71.4%, 81.9%, 75.8%, 69.2%, and 2.7% of the strains were resistant to aztreonam, amikacin, ciprofloxacin, levofloxacin, doxycycline, and tigecycline, respectively. The prevalence of carbapenemase gene bla_KPC-2 was the highest (73.63%, 134/182), followed by bla_NDM-5 (15.38%, 28/182), and bla_NDM-1 (11.54%, 21/182). A total of 15 different sequence types (ST) were identified by MLST, of which ST11 was the most common type (72.53%, 132/182), followed by ST17 (11.54%, 21/182). Conclusions CRKP isolates in Hebei Children's Hospital showed high level resistance to antimicrobial agents. Antimicrobial therapy should be prescribed cautiously according to the results of antimicrobial susceptibility testing to avoid the emergence of resistant strains. KPC-2-producing ST11 type CRKP strains may be prevalent in this hospital. Effective control measures should be taken to avoid further spread of such CRKP strains.

Objective To compare the safety and efficacy of vancomycin in obese patients guided by trough concentration and AUC_24h/MIC, and to provide data for individualized administration of vancomycin in obese patients. Methods We retrospectively collected the data of obese adult patients (BMI ≥ 30 kg/m²) who had severe infection caused by gram-positive cocci and treated with vancomycin intravenously in two Grade A tertiary hospitals in Shanghai from 2012 to 2024. The patients were assigned to trough concentration monitoring group or AUC_24h/MIC monitoring group according to the therapeutic drug monitoring (TDM) method at the time of admission. Nephrotoxicity and efficacy were compared between the two groups of patients. Results A total of 22 obese patients were included in this study, including 12 in the trough concentration monitoring group and 10 in the AUC_24h/MIC monitoring group. No significant difference was found between the two groups in gender, age, BMI, creatinine clearance before treatment, underlying disease, site of infection, pathogen type, or concomitant medications. The proportion of ICU admission was higher in AUC_24h/MIC monitoring group. The length of ICU stay, vancomycin treatment duration, bacterial clearance rate and comprehensive efficacy rate did not show significant difference between the two groups. The average daily dose of vancomycin in trough concentration monitoring group was significantly lower than that in AUC_24h/MIC monitoring group [(1.63 ± 0.59) g vs (2.29 ± 0.72) g, P = 0.026]. The average treatment duration was not significantly different between the two groups [(15.33 ± 10.28) d vs (14.90 ± 6.92) d, P = 0.911]. Compared with the trough concentration monitoring group, the initial peak concentration [(30.99 ± 16.22) mg/L vs (19.41 ± 5.42) mg/L, P = 0.025] and overall peak concentration [(33.67 ± 16.53) mg/L vs (22.08±3.96) mg/L, P = 0.045] of vancomycin were lower in the AUC_24h/MIC monitoring group, but the initial trough concentration [(11.03 ± 8.66) mg/L vs (6.33 ± 4.45) mg/L, P = 0.139] and overall trough concentration [(13.75 ± 9.74) mg/L vs (9.74 ± 4.24) mg/L, P = 0.218] were similar in the two groups. Vancomycin-associated nephrotoxicity did not occur in any group, but 41.7% of the patients in the trough concentration monitoring group reached the threshold of renal toxicity, i.e. trough concentration ≥15 mg/L. Conclusions Vancomycin treatment with conventional dosing regimen still have good clinical efficacy in obese adult patients. Vancomycin therapy guided by AUC_24h/MIC can achieve the target value at lower concentration or exposure, which is promising for reducing vancomycin-associated nephrotoxicity.

Objective To understand the changing profiles of antimicrobial susceptibility of the bacterial strains isolated from patients at Liuzhou Workers' Hospital in Guangxi from 2020 to 2022. Methods The bacteria were isolated, identified, and underwent antimicrobial susceptibility testing using VITEK 2 Compact, disk diffusion method, or E-test. The results were interpreted according to the breakpoints recommended by CLSI M100 32^nd Edition in 2022. The data were analyzed using WHONET 5.6 software. Results A total of 26 254 nonduplicate strains were collected from 2020 to 2022, including Gram-positive bacteria (27.9%) and gram-negative bacteria (72.1%). The prevalence of methicillin-resistant strains was 20.0% in S. aureus (MRSA), and 72.2% in coagulase-negative Staphylococcus (MRCNS). Methicillin-resistant staphylococcal strains were more resistant to most antimicrobial agents than methicillin-susceptible strains (MSSA and MSCNS). None of the staphylococcal strains was resistant to vancomycin, linezolid or tigecycline. Enterococcus faecium strains showed higher resistance rates to most antimicrobial agents than Enterococcus faecalis. None of enterococcal strains was resistant to vancomycin. A few enterococcal strains were resistant to linezolid. Overall, 691 strains of the non-meningitis Streptococcus pneumoniae were isolated from children and 123 strains were isolated from adults. The prevalence of penicillin-resistant S. pneumoniae (PRSP) was 0.4% in the strains from children and 1.6% in the strains from adults. None of S. pneumoniae strains was intermediate to penicillin. The prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKpn) was 1.2%, 1.2%, and 13.8% in 2020, 2021, and 2022, respectively. The prevalence of carbapenem-resistant P. aeruginosa (CRPae) and carbapenem-resistant Acinetobacter baumannii (CRAba) was 10.7% and 68.4% in 2020, 17.5% and 75.2% in 2021, 14.3% and 77.3% in 2022, respectively. About 84.6% of the 1 269 strains of Haemophilus influenzae were isolated from children and 15.4% isolated from adults. The prevalence of beta-lactamase-producing strains was 39.4% in the isolates from children and 46.8% in the isolates from adults. The β-lactamase-producing H. influenzae was resistant to ampicillin. Furthermore, some β-lactamase-nonproducing ampicillin-resistant (BLNAR) H. influenzae strains (27.0%) were also identified. Conclusions Antimicrobial resistance is still serious in this hospital, especially high prevalence of carbapenem-resistant organisms (CRO). Hospital infection prevention and control measures, antibiotic stewardship, and proactive CRO screening should be strengthened. More clinical specimens should be collected for suspected infections. Antimicrobial treatment should be prescribed empirically in time and adjusted when the results of antimicrobial susceptibility testing are available.

Objective The clinical characteristics of 21 cases of nocardiosis were reviewed and antimicrobial resistance of Nocardia strains was analyzed in order to improve the accuracy of clinical diagnosis and treatment of nocardiosis. Methods Clinical data of patients diagnosed with nocardiosis in Zhoukou Central Hospital from 2019-2023 and the corresponding results of antimicrobial susceptibility testing were retrospectively analyzed to summarize the clinical characteristics and outcomes of patients. Results Overall, the 21 cases of nocardiosis included 9 males and 12 females, aged 2-91 years. Underlying disease was reported in 15 patients. Most common type of nocardiosis was pulmonary nocardiosis in 15 cases, followed by skin and soft tissue infection, pleurisy, lymphadenitis, and disseminated nocardiosis. Laboratory tests showed increased levels of WBC, neutrophils percentage, erythrocyte sedimentation rate, C-reactive protein, and procalcitonin. The 21 strains of Nocardia included 4 strains of Nocardia cyriacigeorgica, 2 strains each of Nocardia brasiliensis, Nocardia abscessus, Nocardia asiatica, Nocardia otitidiscaviarum and Nocardia beijingensis, and 1 strain each of Nocardia puris, Nocardia asteroides, Nocardia farcinica, Nocardia pneumoniae, Nocardia amamiensis, and 2 strains of unclassified Nocardia. All of the Nocardia strains (100%) were susceptible to linezolid, amikacin, and trimethoprim-sulfamethoxazole, followed by various levels of susceptibility to cefotaxime, moxifloxacin, imipenem and ceftriaxone, and lower susceptibility rate to cefepime, minocycline, ciprofloxacin and clarithromycin. Antimicrobial susceptibility of Nocardia strains varied with different Nocardia species. Of the 21 patients, two were referred to other hospitals, another two died, two patients received unknown treatment, and the remaining 15 patients were improved after antibiotic treatment, including sulfonamides combined with other antibiotics in 11 cases, other antibiotics in 4 cases. Conclusions Immunocompromised patients or those with underlying diseases are more susceptible to nocardiosis. The clinical features are complex and diverse. Antimicrobial susceptibility of Nocardia strains varied with different Nocardia species. Accurate identification and antimicrobial susceptibility test are essential for prescribing effective antibiotic treatment.

Objective To investigate the distribution and antibiotic resistance profiles of clinical isolates in Beijing Children’s Hospital, Capital Medical University from 2016 to 2022. Methods All the strains isolated from inpatients in Beijing Children’s Hospital during the period from 2016 to 2022 were analyzed. Antimicrobial susceptibility test was conducted by Kirby-Bauer method or automated system. Results were interpreted according to the breakpoints recommended in the CLSI M100 2022 edition. Results A total of 24 904 isolates were analyzed, including Gram-positive bacteria (49.4%) and Gram-negative bacteria (50.6%). The top three Gram-positive bacteria were Staphylococcus aureus (15.6%), coagulase-negative Staphylococcus (14.0%), and Streptococcus pneumoniae (8.9%). The top three Gram-negative bacteria were Klebsiella spp. (8.6%), Pseudomonas aeruginosa (8.6%), and Haemophilus influenzae (8.1%). The prevalence of methicillin-resistant strains was 30.9 % in S. aureus (MRSA) and 82.7% in coagulase-negative Staphylococcus (MRCNS). The prevalence of PRSP was 75.0% (24/32) in meningitis isolates and 2.6% (57/2 195) in non-meningitis isolates. Five strains of E. faecium and 10 strains of E. faecalis were found resistant to linezolid. Two strains of E. faecium were resistant to vancomycin. The prevalence of extended-spectrum beta-lactamases (ESBLs) and carbapenem-resistant strains (CREco) in E. coli isolates was 69.0% and 9.7%, respectively. The prevalence of ESBLs and carbapenem-resistant strains (CRKpn) in K. pneumoniae isolates was 73.7%, and 37.2%, respectively. The prevalence of carbapenem-resistant strains was 21.9% in P. aeruginosa isolates and 59.3% in A. baumannii isolates. β-lactamase was detected in 68.3 % of the H. influenzae isolates. Conclusions Antimicrobial resistance is still serious in children. It is necessary to strength the surveillance of bacterial resistance and use antibiotics rationally in order to curb the spread of drug-resistant strains.

Objective To analyze the relationship between clinical drug utilization and the risk of nosocomial infections among hospitalized patients, and provide evidence for the prevention and control of nosocomial infections. Methods This study adopted a retrospective case-control design. The case group included 209 patients with nosocomial infection reported from January 2023 to December 2023 in a tertiary hospital. The control group included 209 patients without nosocomial infection during the same period. The patients in the control group were selected by stratified sampling based on Charlson Comorbidity Index (CCI). Results Univariate analysis showed that proton pump inhibitors, antacids, immunosuppressants and prior antimicrobial combination therapy increased the risk of nosocomial infection (P < 0.05). Multivariate log-binomial regression analysis showed that proton pump inhibitors, immunosuppressive drugs, and prior antimicrobial combination therapy were correlated with nosocomial infection. The corresponding relative risk (RR) was 1.31 (95% CI: 1.07-1.60), 1.40 (95% CI: 1.02-1.91), and 1.66 (95% CI: 1.01-2.74), respectively. Further analysis indicated that the patients with nosocomial infection had longer time in use of proton pump inhibitors and prior antimicrobial combination therapy than the patients in the control group (Z = –6.331, P < 0.001; Z = –2.667,P = 0.008). The trend Chi-square test showed that there was a dose-response relationship for proton pump inhibitors (χ² = 73.869, P < 0.001), immunosuppressive drugs (χ² = 16.530, P < 0.001), and prior antimicrobial combination therapy (χ² = 35.107, P < 0.001). Conclusions The use of immunosuppressants, proton pump inhibitors and antimicrobial combination therapy increases the risk of nosocomial infections in hospitalized patients. The prolonged use of these drugs will further increase the risk of nosocomial infection.

Objective To explore the risk factors for voriconazole-induced adverse reactions in patients with acquired immunodeficiency syndrome (AIDS) for screening the high-risk populations and safe use of voriconazole. Methods Retrospective analysis was performed on patients who received voriconazole from January 2020 to December 2023. Demographic details, medical history, laboratory tests, concomitant medications, and adverse reactions of patients were collected from the hospital information system (HIS). The potential risk factors for the adverse reactions induced by voriconazole were analyzed by univariate and logistic multivariate analysis. Receiver operating characteristic (ROC) curve was used to analyze the specificity and sensitivity of the risk factors as predictor. Results A total of 170 patients were included in this study. Adverse drug reaction was reported in 62 patients (36.5%). Central nervous system toxicity, hepatotoxicity, and visual impairment were the most common adverse reactions. Univariate analysis showed that the adverse reactions of voriconazole were significantly associated with C-reactive protein, aspartic aminotransferase, aspartic aminotransferase/alanine aminotransferase, and CD4⁺T lymphocytes/CD8⁺T lymphocytes (CD4⁺/CD8⁺). Multivariate analysis indicated that CD4⁺/CD8⁺ was an independent risk factor for voriconazole-induced adverse reactions. ROC curve indicated that CD4⁺/CD8⁺ had a better predictive capability (AUC = 0.756). Conclusions CD4⁺/CD8⁺ should be monitored closely during voriconazole treatment for fungal infection in patients with AIDS. CD4⁺/CD8⁺ may be a good predictor for voriconazole-related psychiatric and visual abnormalities and hepatotoxicity.

Objective To analyze the epidemiological and clinical characteristics of scrub typhus in Liuyang People's Hospital Hunan Province for better diagnosis, treatment, prevention and control of scrub typhus. Methods A retrospective study was conducted on 159 confirmed cases of scrub typhus. The demographic data of patients, clinical manifestations of scrub typhus, laboratory tests, and chest CT findings, complications, treatment, and outcomes were analyzed. Results The 159 patients with scrub typhus included 142 males and 17 females. The average age of patients was (53.8 ± 11.9) (18-82 ) years old. The peak incidence of scrub typhus was in the period from July to September (87.42%). The common clinical manifestations included fever (97.48%), headache (41.51%), and fatigue (23.90%). The most common signs were eschar (92.45%) on the lower limbs (25.16%), scrotum (15.72%), and buttocks (11.32%). Laboratory test results upon admission showed decreased platelet count (64.15%), elevated creatinine (38.36%), elevated AST (90.57%), ALT (80.50%), and LDH (90.57%). Pulmonary imaging study revealed pulmonary inflammation (22.64%), pleural effusion (13.21%), and pericardial effusion (6.29%). The common complications included liver impairment (69.81%) and decreased platelet count (50.94%), as well as other complications such as renal dysfunction, myocardial injury, sepsis, respiratory failure, and disseminated intravascular coagulation (DIC). Doxycycline-based therapies resulted in cure rate of 98.11% (156/159). Three patients died due to severe complications. Conclusions The peak incidence of scrub typhus was in the period from July to September in Hunan Province. Eschar is a key feature for clinical diagnosis. Scrub typhus can affect multiple organ systems, leading to various systemic complications. The cure rate is high with doxycycline treatment, but some patients may die from severe complications due to delayed medical treatment.

Objective To investigate the distribution and antimicrobial resistance profiles of clinically isolated Haemophilus influenzae and Moraxella catarrhalis in hospitals across China from 2015 to 2021, and provide evidence for rational use of antimicrobial agents. Methods Data of H. influenzae and M. catarrhalis strains isolated from 2015 to 2021 in CHINET program were collected for analysis, and antimicrobial susceptibility testing was performed by disc diffusion method or automated systems according to the uniform protocol of CHINET. The results were interpreted according to the CLSI breakpoints in 2022. Beta-lactamases was detected by using nitrocefin disk. Results From 2015 to 2021, a total of 43 642 strains of Haemophilus species were isolated, accounting for 2.91% of the total clinical isolates and 4.07% of Gram-negative bacteria in CHINET program. Among the 40 437 strains of H. influenzae, 66.89% were isolated from children and 33.11% were isolated from adults. More than 90% of the H. influenzae strains were isolated from respiratory tract specimens. The prevalence of β-lactamase was 53.79% in H. influenzae strains. The H. influenzae strains isolated from children showed higher resistance rate than the strains isolated from adults. Overall, 779 strains of H. influenzae did not produce β-lactamase but were resistant to ampicillin (BLNAR). Beta-lactamase-producing strains showed significantly higher resistance rates to these antimicrobial agents than the β-lactamase-nonproducing strains. Of the 16 191 M. catarrhalis strains, 80.06% were isolated from children and 19.94% isolated from adults. M. catarrhalis strains were mostly susceptible to both amoxicillin-clavulanic acid and cefuroxime, evidenced by resistance rate lower than 2.0%. Conclusions The emergence of antibiotic-resistant H. influenzae due to β-lactamase production poses a challenge for clinical anti-infective treatment. Therefore, it is very important to implement antibiotic resistance surveillance for H. influenzae and guide rational antibiotic use. All local clinical microbiology laboratories should actively improve antibiotic susceptibility testing and strengthen antibiotic resistance surveillance for H. influenzae.

Objective To develop and validate an efficient and simple liquid chromatography with tandem mass spectrometry (LC-MS/MS) method for determination of polymyxin E in human plasma, and apply the established method in therapeutic drug monitoring (TDM) of polymyxin E. Methods The LC-MS/MS platform was based on AB SCIEX HPLC-4500MD system. Gradient elution was performed with 0.2% formic acid in water and 0.2% formic acid in acetonitrile. Phenomenex Kinetex XB-C18 column (100 mm × 2.1 mm, 2.6 μm) were used. The analytes were detected by electrospray ionization (ESI) positive multiple reaction monitoring mode. The ion pairs for analytes (polymyxins E1, E2) and internal standard (polymyxins B1) were m/z 390.7→101.3, m/z 386.0→101.2, and m/z 402.3→101.2, respectively. Plasma samples were processed with protein precipitation method. Results Polymyxin E1 and E2 showed good linearity in the range of 0.031 2 - 6.24 mg/L and 0.006 15 - 1.23 mg/L, respectively. The within-run accuracy of polymyxin E1 and E2 in plasma ranged from 89.4% to 99.8% and 91.5% to 108.2%, respectively, while the between-run accuracy ranged from 91.8% to 104.7% and 95.6% to 105.2%, respectively. The within-run precision of polymyxin E1 and E2 in plasma ranged from 4.9% to 8.9% and 2.8% to 8.5%, respectively, while the between-run precision ranged from 4.1% to 7.6% and 4.2% to 9.8%, respectively. The average internal standard normalized matrix effect factors of polymyxins E1 and E2 were 96.9%-111.2% and 106.1%-112.8% in blank plasma samples from 6 different sources, 102.5%-106.8% and 98.8%-105.2% in lipemic plasma, respectively, 107.8%-108.9% and 106.9%-107.4% in hemolyzed plasma, respectively. The precision of matrix effects was less than 15.0%. The average recovery rate was 102.9% - 107.5% for polymyxin E1 and E2, and 107.0% for internal standard polymyxin B1. The precision was less than 3.7%. Conclusions In this study, a simple and efficient LC-MS/MS method was established for determination of polymyxin E1 and E2 in human plasma, which is reliable in the therapeutic drug monitoring and pharmacokinetic study of polymyxin E.

Objective To improve the diagnosis and treatment of Streptococcus liver abscesses by analyzing the clinical presentations, antibiotic susceptibility, and treatment strategies of patients. Methods A retrospective analysis was conducted on 21 patients diagnosed with liver abscess caused by Streptococcus from June 2012 to June 2022. The data included demographic information, clinical characteristics, laboratory tests, imaging findings, treatment strategies, and outcomes. Results The 21 patients were 29 to 77 years of age, and 81.0% were male. Clinical manifestations included fever, chills, fatigue, and abdominal pain. Some patients also had headache and altered consciousness, indicating possible concomitant brain abscess. Hematogenous dissemination and biliary tract origin were the most common routes of infection. The predominant pathogen was Streptococcus anginosus group (76.2%). Single pathogen infection was found in 12 cases and mixed infection in 9 cases. All isolates were sensitive to penicillin, cefotaxime, vancomycin, and levofloxacin, but 36.4% (4/11) of the isolates showed resistance to erythromycin and clindamycin. Four patients developed metastatic abscesses, and two experienced septic shock. The main treatment approach was a combination of antibiotics and percutaneous liver puncture drainage, resulting in improvement in 18 patients. Conclusions Liver abscesses caused by Streptococcus are usually non-specific in terms of symptoms. Streptococcus anginosus group is the primary pathogen. Antibiotics combined with percutaneous drainage is an effective treatment approach. It is crucial for clinicians to be aware of potential brain abscesses and the necessity of early intervention.

Objective To examine the diagnosis and treatment of disseminated infection caused by Enterocytozoon bieneusi in a child with leukemia and improve the awareness of the pathogen in clinical and laboratory practice. Methods A case of disseminated infection caused by Enterocytozoon bieneusi in a child with leukemia in Shanghai Children’s Hospital was retrospectively analyzed, including diagnosis and treatment details. Similar cases were identified from PubMed, Wanfang Data, VIP, and CNKI databases since database establishment until June 30, 2024, using search terms “Enterocytozoon bieneusi”. The relevant literature was reviewed. Results This child had acute lymphoblastic leukemia as the underlying disease and was admitted to hospital for antimicrobial treatment due to fever and abdominal discomfort. The case was considered bacterial infection complicated with Enterocytozoon bieneusi infection, confirmed by detection of Klebsiella pneumoniae in blood and detection of Enterocytozoon bieneusi in blood and ascites by metagenomic next-generation sequencing (mNGS). The treatment was switched to tigecycline plus trimethoprim-sulfamethoxazole at a sufficient dose, which resulted in resolution of symptoms. Six months later, the patient suffered from acute lymphoblastic leukemia and bone marrow depression, Enterocytozoon bieneusi disseminated infection, septic shock. Her family gave up treatment and the child died. Literature review indicated that most patients infected with Enterocytozoon bieneusi had underlying conditions such as organ transplantation, AIDS, and leukemia associated with poor immunity. The onset symptoms are diarrhea, abdominal discomfort, and fever. Enterocytozoon bieneusi was detected by using methods such as modified Masson's trichrome stain, fluorescent calcofluor white staining, molecular detection techniques, and immunofluorescence. The patients were treated with drugs such as albendazole, nitazoxanide, fumagillin, and trimethoprim-sulfamethoxazole. Conclusions Enterocytozoon bieneusi is an opportunistic pathogenic fungus that infects immunocompromised patients and can cause abdominal discomfort, diarrhea, fever, and even disseminated infection and death. Conventional laboratory methods cannot culture Enterocytozoon bieneusi. Molecular detection techniques can be used to identify the pathogen early.

Objective This study aimed to evaluate the interaction between antiretroviral drug efavirenz and anti-tuberculosis 1H3P3 (isoniazid plus rifapentine) in people living with HIV. Methods HIV-positive individuals on efavirenz-containing (600 mg) antiretroviral therapy (ART) received 1H3P3 regimen containing rifapentine (450 mg) plus isoniazid (400 mg) 3 times a week for 1 month. Efavirenz concentrations were measured at weeks 0, 2, 4, 8. Rifapentine concentration was determined at weeks 2 and 4. HIV RNA load was determined at weeks 0 and 8. Treatment target was efavirenz concentration > 1 mg/L. The anti-TB prevention was considered acceptable if the target of efavirenz concentration was achieved in more than 80% of participants. The participants were followed up for 18 months to evaluate the efficacy of treatment. Results Thirty-one participants living with HIV were enrolled in the study. Two participants were excluded from PK analysis because his/her baseline efavirenz concentration < 1 mg/L, suggesting poor treatment adherence. Evaluable PK data were available for 29 participants, including 23 (79.3%) males. The median [interquartile range (IQR)] age of the participants was 43.0 (32.5, 53.5) years. The median (IQR) efavirenz plasma concentration was 2.33 (1.96, 2.34) mg/L at week 0, 2.32 (1.90, 3.28) mg/L at week 2, 2.07 (1.83, 3.09) mg/L at week 4, and 2.71 (2.14, 3.33) mg/L at week 8. Efavirenz concentration did not show significant difference between the 4 time points (P > 0.05). Median (IQR) rifapentine concentration was 9.36 (6.23, 16.47) mg/L at week 2, and 9.36 (6.41, 15.56) mg/L at week 4. Rifapentine concentration did not show significant difference between week 2 and week 4 (P > 0.05). Efavirenz concentrations was > 1 mg/L in all participants at weeks 2, 4, and 8. Furthermore, efavirenz concentration was significantly higher in females and patients with body weight < 60 kg compared with males and those with body weight ≥60 kg (P < 0.05). None of the participants had symptoms or signs of active tuberculosis during 18-month follow-up. Conclusions Isoniazid plus rifapentine (1H3P3 regimen) did not have significant effect on the plasma concentrations of efavirenz.

Objective To investigate the correlation between baseline plasma soluble triggering receptor expressed on myeloid cell-1 (sTREM-1), steroid hormone cortisol and dehydroepiandrosterone (DHEA), immunoendocrine markers, and disease severity in patients with pulmonary tuberculosis (PTB). Methods From March 2020 to May 2022, 76 PTB patients and 78 healthy controls were recruited. The plasma sTREM-1 levels were compared between controls and PTB patients. Plasma sTREM-1 and C-reactive protein (CRP), interleukin (IL)-6 and interferon (IFN)-γ, erythrocyte sedimentation rate (ESR), steroid hormone cortisol and dehydroepiandrosterone (DHEA) were analyzed to correlate with inflammatory transcripts (IL-6, IFN-γ) in peripheral blood mononuclear cells. Results The sTREM, CRP, ESR, IL-6, IFN-γ, cortisol and cortisol/DHEA were significantly increased (P < 0.05) while DHEA was significantly decreased (P < 0.05) in PTB patients compared with the control group. Futhermore, severe PTB patients had higher sTREM-1 and ESR levels than mild and moderate PTB patients. Spearman correlation analysis showed that sTREM-1 was significantly positively correlated with CRP in all patients (P < 0.05). Only in patients with severe PTB, sTREM-1 was significantly positively correlated with cortisol/DHEA (P < 0.05), and significantly negatively correlated with DHEA (P < 0.05). Conclusions High plasma sTREM-1 levels may be an important factor contributing to the persistence of immunoendocrine imbalance specific to advanced disease in patients with PTB.

Objective To investigate the efficacy of voriconazole in the treatment of pulmonary tuberculosis complicated with chronic pulmonary aspergillosis (CPA) based on CYP2C19 gene polymorphism detection and examine the factors affecting the efficacy for improving targeted therapy in clinical practice. Methods A total of 207 patients with pulmonary tuberculosis complicated with CPA treated in the Third People's Hospital of Kunming from December 2018 to November 2022 were randomly assigned to an observation group (105 cases) or a control group (102 cases). The patients in the control group received standard voriconazole treatment, while the patients in the observation group had their voriconazole regimen tailored based on CYP2C19 genotyping results. Plasma drug concentration levels, efficacy, and safety were compared between the two groups and in terms of CYP2C19 genotypes. Logistic regression analysis was used to identify the factors affecting treatment efficacy. Results The observation group showed significantly higher plasma voriconazole concentrations and overall antifungal efficacy compared to the control group (P < 0.05). In the observation group, CYP2C19 genotyping identified 37 extensive metabolizers (EM), 47 intermediate metabolizers (IM), and 21 poor metabolizers (PM). Plasma concentration of voriconazole did not show significant difference between EM and IM (P > 0.05), but both PM and IM were associated with significantly lower plasma concentration of voriconazole than PM (P < 0.05). The clinical efficacy rate was 100% for PM, 91.5% for IM, and 83.8% for EM (P < 0.05). The incidence of adverse events did not show significant difference among the three genotypes (P > 0.05). Logistic regression analysis revealed that lung cavitation, hypoalbuminemia, and agranulosis were significantly correlated with therapeutic efficacy (P < 0.05). Conclusions CYP2C19 gene polymorphism detection is valuable in clinical practice. It can inform anti-aspergillus therapy with voriconazole to effectively improve symptoms and clinical efficacy in patients with pulmonary tuberculosis complicated with CPA. Meanwhile, clinicians should be aware of the factors such as hypoproteinemia, agranulocytosis, and lung cavitation that may affect the efficacy of voriconazole.

Objective To investigate the distribution and antimicrobial resistance profiles of common pathogens isolated from cerebrospinal fluid (CSF) in CHINET program from 2015 to 2021. Methods The bacterial strains isolated from CSF were identified in accordance with clinical microbiology practice standards. Antimicrobial susceptibility test was conducted using Kirby-Bauer method and automated systems per the unified CHINET protocol. Results A total of 14 014 bacterial strains were isolated from CSF samples from 2015 to 2021, including the strains isolated from inpatients (95.3%) and from outpatient and emergency care patients (4.7%). Overall, 19.6% of the isolates were from children and 80.4% were from adults. Gram-positive and Gram-negative bacteria accounted for 68.0% and 32.0%, respectively. Coagulase negative Staphylococcus accounted for 73.0% of the total Gram-positive bacterial isolates. The prevalence of MRSA was 38.2% in children and 45.6% in adults. The prevalence of MRCNS was 67.6% in adults and 69.5% in children. A small number of vancomycin-resistant Enterococcus faecium (2.2%) and linezolid-resistant Enterococcus faecalis (3.1%) were isolated from adult patients. The resistance rates of Escherichia coli and Klebsiella pneumoniae to ceftriaxone were 52.2% and 76.4% in children, 70.5% and 63.5% in adults. The prevalence of carbapenem-resistant E. coli and K. pneumoniae (CRKP) was 1.3% and 47.7% in children, 6.4% and 47.9% in adults. The prevalence of carbapenem-resistant Acinetobacter baumannii (CRAB) and Pseudomonas aeruginosa (CRPA) was 74.0% and 37.1% in children, 81.7% and 39.9% in adults. Conclusions The data derived from antimicrobial resistance surveillance are crucial for clinicians to make evidence-based decisions regarding antibiotic therapy. Attention should be paid to the Gram-negative bacteria, especially CRKP and CRAB in central nervous system (CNS) infections. Ongoing antimicrobial resistance surveillance is helpful for optimizing antibiotic use in CNS infections.

Objective To investigate the susceptibility of Cryptococcus neoformans strains to antifungal drugs and examine the relevant clinical manifestations and laboratory test results in a tertiary hospital in Shanghai during the period from 2019 to 2023. Methods The isolates were identified by MALDI-TOF and biochemical identification cards. The minimum inhibitory concentration (MIC) values of 5-fluorocytosine, amphotericin B, fluconazole, voriconazole, and itraconazole against C. neoformans strains were measured using broth microdilution method. The corresponding clinical data were reviewed and compared. Results Majority (78.7%) of the 75 strains of C. neoformans were isolated from cerebrospinal fluid (CSF). The prevalence of wild type (WT) strains was the lowest (36.0%) for itraconazole and the highest (94.7%) for voriconazole. Cryptococcus capsular antigen test was positive in 62 strains. The results of Cryptococcus capsular antigen test was consistent with fungal culture in 96.9% of the cases. Conclusions Most of the C. neoformans strains were isolated from CSF. The prevalence of non-WT C. neoformans strains was the highest for itraconazole. The prevalence of WT C. neoformans strains was the highest for voriconazole.

Objective To understand the changing composition and antibiotic resistance of bacterial species in the clinical isolates from outpatient and emergency department (hereinafter referred to as outpatients) and inpatient children over time in various hospitals, and to provide laboratory evidence for rational antibiotic use. Methods The data on clinically isolated pathogenic bacteria and antimicrobial susceptibility of isolates from outpatients and inpatient children in the CHINET program from 2015 to 2021 were collected and analyzed. Results A total of 278 471 isolates were isolated from pediatric patients in the CHINET program from 2015 to 2021. About 17.1% of the strains were isolated from outpatients, primarily group A β-hemolytic Streptococcus, Escherichia coli, and Staphylococcus aureus. Most of the strains (82.9%) were isolated from inpatients, mainly S. aureus, E. coli, and H. influenzae. The prevalence of methicillin-resistant S. aureus (MRSA) in outpatients (24.5%) was lower than that in inpatient children (31.5%). The MRSA isolates from outpatients showed lower resistance rates to the antibiotics tested than the strains isolated from inpatient children. The prevalence of vancomycin-resistant Enterococcus faecalis or E. faecium and penicillin-resistant S. pneumoniae was low in either outpatients or inpatient children. S. pneumoniae, β-hemolytic Streptococcus and S. viridans showed high resistance rates to erythromycin. The prevalence of erythromycin-resistant group A β-hemolytic Streptococcus was higher in outpatients than that in inpatient children. The prevalence of β-lactamase-producing H. influenzae showed an overall upward trend in children, but lower in outpatients (45.1%) than in inpatient children (59.4%). The prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKpn), carbapenem-resistant Pseudomonas aeruginosa (CRPae) and carbapenem-resistant Acinetobacter baumannii (CRAba) was 14%, 11.7%, 47.8% in outpatients, but 24.2%, 20.6%, and 52.8% in inpatient children, respectively. The prevalence of multidrug-resistant E. coli, K. pneumoniae, Proteus mirabilis, P. aeruginosa and A. baumannii strains was lower in outpatients than in inpatient children. The prevalence of fluoroquinolone-resistant E. coli, ESBLs-producing K. pneumoniae, ESBLs-producing P. mirabilis, carbapenem-resistant E. coli (CREco), CRKpn, and CRPae was lower in children in outpatients than in inpatient children, but the prevalence of CRAba in 2021 was higher than in inpatient children. Conclusions The distribution of clinical isolates from children is different between outpatients and inpatients. The prevalence of MRSA, ESBL, and CRO was higher in inpatient children than in outpatients. Antibiotics should be used rationally in clinical practice based on etiological diagnosis and antimicrobial susceptibility test results. Ongoing antimicrobial resistance surveillance and prevention and control of hospital infections are crucial to curbing bacterial resistance.

Objective To investigate the value of neutrophil to lymphocyte ratio (NLR) and lymphocyte to monocyte ratio (LMR) in the diagnosis and prognosis of patients with sepsis. Methods From January 2022 to December 2022, patients in the First Affiliated Hospital of Soochow University were recruited in this study, including 47 patients with sepsis (sepsis group), 31 with infection but not diagnosed as sepsis (infection group), and 25 healthy individuals (control group) were simultaneously chosen. Patients with sepsis were assigned to non-shock group (32 cases) or shock group (15 cases), survivors group (38 cases) or deaths group (9 cases). Procalcitonin (PCT), C-reactive protein (CRP) and routine blood tests were analyzed and compared between groups. Spearman's correlation test was used to analyze the correlation among NLR, LMR and PCT, PCR, lymphocyte, monocyte, neutrophil, platelet and SOFA scores, the diagnostic value of NLR and LMR in sepsis was evaluated by plotting the receiver operating characteristic (ROC) curve. Results The NLR was 12.54 (7.53, 23.42) in sepsis group, 3.85 (1.83, 5.64) in infection group, and 1.71 (1.39, 2.20) in normal control group. The corresponding LMR was 1.58 (1.07, 3.03), 2.81 (1.53, 4.76), and 5.16 (4.04, 6.59), respectively. NLR was negatively correlated with LMR (r_s = –0.469, P < 0.05). The NLR on day 7 (NLR7) was 6.56 (3.90, 10.72) in the non-shock group and 15.20 (7.53, 27.31) in shock group. The corresponding ΔNLR7 was –1.64 (–5.75, 0.41) and 1.98 (–0.48, 13.79) in the two groups. The shock group had significantly higher ΔNLR7 than the non-shock group (P < 0.05). NLR7 was 7.10 (4.09, 12.96) in the survivors and 15.20 (10.45, 32.82) in the deaths group. The corresponding ΔNLR7 was –0.65 (–5.58, 1.58) and 5.02 (–1.12, 17.06) in the two groups. The deaths group had significantly higher ΔNLR7 than the survivors group (P < 0.05). The LMR on day 7 (LMR7) was 2.22 (1.64, 3.78) in the non-shock group and 1.29 (0.66, 2.03) in shock group. The corresponding ΔLMR7 was 0.38 (–0.37, 1.17) and –0.19(–0.78, 0.25) in the two groups. The shock group had significantly lower ΔLMR7 than the non-shock group (P < 0.05). LMR7 was 2.12 (1.49, 3.42) in the survivors group and 1.09 (0.53, 1.78) in the deaths group. The deaths group had significantly lower LMR7 than the survivors group (P < 0.05). The AUC of NLR was 0.959 1 (95% CI: 0.910 5-1.000 0) in diagnosis of sepsis. The best cut-off value was 4.16. The AUC of LMR was 0.913 6 (95% CI: 0.846 4-0.980 8) in diagnosis of sepsis. The best cut-off value was 3.21. Conclusions NLR and LMR can be used to evaluate the severity and prognosis of patients with sepsis. These two markers may play a role in the diagnosis of sepsis.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units (PICU) in China for better antimicrobial therapy. Methods Clinical isolates were collected from 17 institutions, including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1, 2020 to December 31, 2022. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems. Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute (CLSI) in 2020. Results A total of 10 688 isolates were collected, including gram-positive organisms (39.2%) and gram-negative organisms (60.8%). The top three organisms were S. aureus (13.6%, 1 453/10 688), A. baumannii (10.0%, 1 067/10 688), and coagulase-negative Staphylococcus (9.9%, 1 058/10 688). Multi-drug resistant organisms (MDROs) were very common in children. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Enterobacterales (CRE), carbapenem-resistant E. coli, carbapenem-resistant K. pneumoniae (CRKP), carbapenem-resistant A. baumannii (CRAB), and carbapenem-resistant P. aeruginosa (CRPA) was 41.1%, 19.4%, 8.8%, 30.9%, 67.4%, and 28.8%, respectively. Overall, more than 50% of Enterobacteriales isolates were resistant to cephalosporins, while nearly 25% of Enterobacteriales isolates were resistant to carbapenems. MDROs were highly resistant to commonly used antibiotics. More than 80% of CRE and CRAB strains were resistant to all beta-lactam antibiotics. CRE and CRAB showed low resistance rates to tigecycline and polymyxin. CRPA showed lower resistance rates to piperacillin, beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins. All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline. None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin, vancomycin, or linezolid. The prevalence of β-lactamase-negative ampicillin-resistant (BLNAR) strains was 43.3% in Haemophilus influenzae. Conclusions MDROs were prevalent in PICU. It is necessary to establish an effective multidisciplinary team (MDT) to control the antimicrobial resistance.

Objective To evaluate the efficacy and safety of amoxicillin-clavulanate (10:1) for injection in the treatment of community-acquired pneumonia (CAP) in adult patients. Methods Eligible patients were randomized to receive amoxicillin-clavulanate (10:1) 2.2 g or ampicillin-sulbactam (2:1) 3.0 g via intravenous infusion q12h or q8h for 7 to 14 days. The primary endpoint was to the clinical efficacy 7-14 days after discontinuation of treatment. The secondary endpoints included microbiological efficacy and safety. Results All enrolled patients (n=324) were included in the full analysis set (FAS), specifically 165 patients receiving amoxicillin sodium-clavulanate potassium (10:1) and 159 patients receiving ampicillin sodium-sulbactam sodium (2:1). The clinical cure rate was 78.8% (130/165) for amoxicillin-clavulanate (10:1) and 77.4% (123/159) for ampicillin-sulbactam 7-14 days after end of treatment (P > 0.05). The clinical cure rate was 87.5% (126/144) for amoxicillin-clavulanate (10:1) and 87.4% (111/127) for ampicillin-sulbactam (2:1) in per protocol set (P > 0.05). Therefore, amoxicillin-clavulanate (10:1) was non-inferior to ampicillin-sulbactam in the primary endpoint in the treatment of CAP in adult patients. The overall bacterial eradication rate was 94.4% (34/36) for amoxicillin-clavulanate (10:1) and 89.3% (25/28)for ampicillin-sulbactam (P > 0.05). The common study drug-related clinical adverse event were abnormalities of hepatic function in both the amoxicillin-clavulanate (10:1) group (4.8%, 8/165) and ampicillin-sulbactam group (3.1%, 5/159) (P > 0.05). Conclusions Amoxicillin-clavulanate (10:1) 2.2 g IV infusion q12h or q8h for 7-14 days was noninferior to ampicillin-sulbactam in terms of clinical and microbiological efficacy in the treatment of CAP in adult patients. The safety of the two dosing regimens was comparable.

Objective To compare the anti fungal efficacy and safety of amphotericin B cholesteryl sulfate complex (amphotericin B colloidal dispersion, ABCD) and amphotericin B for injection (amphotericin B deoxycholate, AmB-D) in the treatment of AIDS complicated with talaromycosis (TSM). Methods A total of 80 patients who were diagnosed with AIDS and complicated with TSM from December 2021 to January 2024 in Department of Infection, Kunming Third People's Hospital were included in the study. The patients were randomized to receive ABCD (n=40) via intravenous infusion or AmB-D (control, n=40) via IV infusion protected from light. The overall treatment efficacy rate, CD4⁺ T lymphocyte count, routine blood tests, liver and kidney function tests, K⁺ concentration, and the incidence of adverse drug reactions (ADR) during study were compared between the two treatment groups. Results The overall efficacy rate was 87.5% (35/40) in ABCD group and 80.0% (32/40) in the control (AmB-D) group (P > 0.05). WBC, hemoglobin, and platelet count were significantly higher after treatment compared with pretreatment levels (P < 0.05) in both groups. The CD4⁺ T lymphocyte count was higher after treatment compared with pretreatment levels in both groups. And the CD4⁺ T lymphocyte count in ABCD group was significantly higher than that in the control group (P < 0.05). The levels of total bilirubin, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and serum creatinine increased after treatment in both groups. Blood urea nitrogen and serum creatinine increased significantly in control group compared with ABCD group (P < 0.05). After treatment, serum K⁺ concentration decreased significantly in control group compared with the pretreatment level and compared with ABCD group (P < 0.05). The incidence of adverse events in ABCD group was significantly lower than that in the control group. The time to renal injury was delayed significantly (P < 0.05). Conclusions In the treatment of AIDS complicated with TSM, the efficacy of ABCD was comparable to AmB-D. The incidence of hepatic impairment did not show significant difference between ABCD and AmB-D. However, ABCD is associated with less renal impairment, lower incidence of adverse events, and better safety, which is valuable for clinical use.

Objective To understand the distribution and antimicrobial resistance profiles of bacterial strains isolated from blood cultures at Yunyang County People’s Hospital from 2019 to 2023. Methods The data of bacterial isolates from blood samples and the results of antimicrobial susceptibility testing were analyzed retrospectively from 2019 to 2023 at Yunyang County People’s Hospital. Results A total of 3 789 bacterial strains were isolated from blood culture, including 1 931 (51.0%) strains of Gram negative bacteria and 1 858 (49.0%) strains of Gram positive bacteria. Coagulase negative Staphylococcus (33.3%), Escherichia coli (25.4%), Klebsiella pneumoniae (13.7%), Staphylococcus aureus (9.9%), and Enterobacter cloacae (1.8%) were the top five bacterial pathogens. Antimicrobial susceptibility testing showed that the prevalence of methicillin-resistant strains was 27.1% in S. aureus, 34.5% in S. epidermidis, and 49.9% in other coagulase-negative Staphylococcus. Methicillin resistant strains (MRSA, MRSE, and other MRCNS) showed significantly higher resistance rates to most antibiotics than corresponding methicillin-susceptible strains (MSSA, MSSE, and other MSCNS). No staphylococcal isolates were resistant to vancomycin, teicoplanin, linezolid, or tigecycline. Enterococcus faecium showed significantly higher resistance rate to antibiotics than Enterococcus faecalis. No enterococcal strains were resistant to vancomycin, teicoplanin, linezolid, or tigecycline. No streptococcal isolates were found resistant to vancomycin or linezolid. Serratia marcescens strains had a resistance rate of 25.0% to carbapenems. All other Enterobacterales species showed a resistance rate of less than 10.0% to carbapenems. No Enterobacterales isolates were found resistant to tigecycline. The resistance rates of P. aeruginosa to imipenem and meropenem were 5.7% and 3.8%, respectively. No P. aeruginosa isolates were found resistant to colistin. The resistance rates of Acinetobacter baumannii to imipenem and meropenem were 41.4% and 38.0%, respectively. Conclusions The proportion of Gram negative bacteria is slightly higher than that of Gram positive bacteria in the bacterial isolates from blood samples at Yunyang County People’s Hospital. The prevalence of MRSA and MRCNS is relatively high, while A. baumannii and S. marcescens showed high resistance rates to carbapenems. Antimicrobial resistance surveillance should be strengthened for the bacterial isolates from blood samples in order to learn the changing resistance profiles, use antibiotics reasonably, and prevent the spread of drug-resistant bacteria.

Objective To investigate the antimicrobial resistance of clinical isolates from elderly patients (≥65 years) in major medical institutions across China. Methods Bacterial strains were isolated from elderly patients in 52 hospitals participating in the CHINET Antimicrobial Resistance Surveillance Program during the period from 2015 to 2021. Antimicrobial susceptibility test was carried out by disk diffusion method and automated systems according to the same CHINET protocol. The data were interpreted in accordance with the breakpoints recommended by the Clinical and Laboratory Standards Institute (CLSI) in 2021. Results A total of 514 715 nonduplicate clinical isolates were collected from elderly patients in 52 hospitals from January 1, 2015 to December 31, 2021. The number of isolates accounted for 34.3% of the total number of clinical isolates from all patients. Overall, 21.8% of the 514 715 strains were gram-positive bacteria, and 78.2% were gram-negative bacteria. Majority (90.9%) of the strains were isolated from inpatients. About 42.9% of the strains were isolated from respiratory specimens, and 22.9% were isolated from urine. More than half (60.7%) of the strains were isolated from male patients, and 39.3% isolated from females. About 51.1% of the strains were isolated from patients aged 65-<75 years. The prevalence of methicillin-resistant strains (MRSA) was 38.8% in 32 190 strains of Staphylococcus aureus. No vancomycin- or linezolid-resistant strains were found. The resistance rate of E. faecalis to most antibiotics was significantly lower than that of Enterococcus faecium, but a few vancomycin-resistant strains (0.2%, 1.5%) and linezolid-resistant strains (3.4%, 0.3%) were found in E. faecalis and E. faecium. The prevalence of penicillin-susceptible S. pneumoniae (PSSP), penicillin-intermediate S. pneumoniae (PISP), and penicillin-resistant S. pneumoniae (PRSP) was 94.3%, 4.0%, and 1.7% in nonmeningitis S. pneumoniae isolates. The resistance rates of Klebsiella spp. (Klebsiella pneumoniae 93.2%) to imipenem and meropenem were 20.9% and 22.3%, respectively. Other Enterobacterales species were highly sensitive to carbapenem antibiotics. Only 1.7%-7.8% of other Enterobacterales strains were resistant to carbapenems. The resistance rates of Acinetobacter spp. (Acinetobacter baumannii 90.6%) to imipenem and meropenem were 68.4% and 70.6% respectively, while 28.5% and 24.3% of P. aeruginosa strains were resistant to imipenem and meropenem, respectively. Conclusions The number of clinical isolates from elderly patients is increasing year by year, especially in the 65-<75 age group. Respiratory tract isolates were more prevalent in male elderly patients, and urinary tract isolates were more prevalent in female elderly patients. Klebsiella isolates were increasingly resistant to multiple antimicrobial agents, especially carbapenems. Antimicrobial resistance surveillance is helpful for accurate empirical antimicrobial therapy in elderly patients.

Objective To investigate the risk factors for acute respiratory failure in immunocompromised patients with Pneumocystis jirovecii pneumonia (PJP). Methods Clinical data of 123 immunocompromised patients complicated with PJP hospitalized at Mengchao Hepatobiliary Hospital of Fujian Medical University from January 2021 to December 2023 were retrospectively collected and analyzed. SPSS 22.0 statistical software package was used to perform multivariate binary logistic regression analysis to identify risk factors for acute respiratory failure in PJP patients. Results Among the 123 PJP patients, 77 were HIV-positive, and 46 were HIV-negative. HIV-negative PJP patients were more likely to have comorbidities such as hypertension (P < 0.001), diabetes mellitus (P < 0.001), coronary heart disease (P = 0.034), chronic kidney disease (P < 0.001), chronic liver disease (P = 0.019), chronic lung disease (P = 0.011), and malignant tumor (P < 0.001). They were also more prone to respiratory failure (P < 0.001) and ICU admission (P < 0.001). The HIV-positive patients had significantly lower CD4⁺ T lymphocyte counts and albumin levels (P < 0.001). Forty patients developed acute respiratory failure, and six patients died. Multivariate analysis showed that high neutrophil-to-lymphocyte ratio (NLR) (P = 0.031), non-HIV infection (P = 0.002), and concomitant infections with other pathogens (P < 0.001) were independent risk factors for incidence of respiratory failure. ROC curve analysis revealed that the area under the curve (AUC) was 0.686 (0.584, 0.789) for non-HIV infection, 0.731 (0.637, 0.826) for concomitant infections with other pathogens, 0.648 (0.546, 0.750) for NLR. The predicted probability was 0.845 (0.778, 0.912). Conclusions Non-HIV infection, high NLR, and concomitant infections with other pathogens are independent risk factors for incidence of respiratory failure in PJP patients. The panel combining these factors provides a higher predictive value for respiratory failure. Timely assessment of patient condition and early treatment are vital for better outcomes.

Objective To investigate the application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) combined with serum separator tube and turbidimetry in the direct identification of pathogens in sterile body fluids. Methods A total of 284 positive sterile body fluid specimens (blood, hydrothorax, ascites, bile, and cerebrospinal fluid) infected by a single pathogen with a blood culture instrument alarm time less than 48 h were collected from January to December 2023 in the Department of Laboratory Medicine at Suzhou Ninth People's Hospital. All the specimens were tested by turbidimeter for pathogen concentration. And the reliability of the identification results was judged by MALDI-TOF MS scores according to different concentrations of the main pathogens. Results The lowest concentration of microorganism for achieving reliable results was 3.0 mcf for Escherichia coli, 2.0 mcf for Klebsiella pneumoniae, 3.0 mcf for Staphylococcus aureus, 3.5 mcf for Enterococcus faecalis and 4.0 mcf for Candida when identified by MALDI-TOF MS. The results were compared between VITEK 2 identification, routine MALDI-TOF MS identification, and direct MALDI-TOF MS identification. The results of routine MALDI-TOF MS identification and VITEK identification were consistent in 282 cases. The concentration greater than 1.7 was found in 272 cases with direct MALDI-TOF MS, and the sensitivity of MALDI-TOF MS was 95.8% (272/284). The results did not show significant difference between the 3 identification methods (χ² = 2.09, P = 0.55). Conclusions MALDI-TOF MS combined with serum separator tube and turbidimetry is a reliable and innovative technique for identifying pathogens in sterile body fluids. It is rapid and accurate, and may be valuable for early etiological diagnosis in clinical practice.

Objective To analyze the risk factors for upper arm ports (UAP) related infections and develop a nomogram for predicting the UAP related infections. Methods Patients (n = 6 028) with UAP between 2014 and 2023 in Renji Hospital, Shanghai Jiao Tong University School of Medicine were included and assigned to a training set (n = 4 219) or a validation set (n = 1 809). Least Absolute Shrinkage and Selection Operator (LASSO) regression were built and non-zero factors were screened out. Multivariate logistic regression was performed for these non-zero factors to screen significant factors out for constructing a prediction model. The performance of the model was evaluated by the area under curve (AUC) of the receiver operating characteristic (ROC) curves, calibration curves, the decision curve analysis (DCA) curve, and clinical impact curves (CICs) in both training set and validation set. Results The model incorporated gender, venous access, venous status, catheter-related thrombosis (CRT), and diameter of catheter. The model performed well. The AUC of ROC was 0.801 in the training set and 0.746 in the validation set. The calibration curve was close to the ideal curve, indicating good discriminative ability of the model. The DCA curve suggested that the model could help make beneficial clinical decisions when the risk assessment value was 30%-41%. CICs proved that the model had good clinical value. Conclusions A model was successfully constructed to predict UAP-related infections. The brachial/basilic vein and 5F catheter was proposed as the first choice. Thicker catheter diameter, male, CRT, abnormal venous status, and axillary vein approach may increase the risk of UAP related infection.