Objective To monitor the susceptibility of clinical isolates to antimicrobial agents in healthcare facilities in major regions of China in 2023. Methods Clinical isolates collected from 73 hospitals across China were tested for antimicrobial susceptibility using a unified protocol based on disc diffusion method or automated testing systems. Results were interpreted using the 2023 Clinical & Laboratory Standards Institute (CLSI) breakpoints. Results A total of 445 199 clinical isolates were collected in 2023, of which 29.0% were gram-positive and 71.0% were gram-negative. The prevalence of methicillin-resistant strains in Staphylococcus aureus, Staphylococcus epidermidis and other coagulase-negative Staphylococcus species (excluding Staphylococcus pseudintermedius and Staphylococcus schleiferi) (MRSA, MRSE and MRCNS) was 29.6%, 81.9% and 78.5%, respectively. Methicillin-resistant strains showed significantly higher resistance rates to most antimicrobial agents than methicillin-susceptible strains (MSSA, MSSE and MSCNS). Overall, 92.9% of MRSA strains were susceptible to trimethoprim-sulfamethoxazole and 91.4% of MRSE strains were susceptible to rifampicin. No vancomycin-resistant strains were found. Enterococcus faecalis had significantly lower resistance rates to most antimicrobial agents tested than Enterococcus faecium. A few vancomycin-resistant strains were identified in both E. faecalis and E. faecium. The prevalence of penicillin-susceptible Streptococcus pneumoniae was 93.1% in the isolates from children and and 95.9% in the isolates from adults. The resistance rate to carbapenems was lower than 15.0% for most Enterobacterales species except for Klebsiella, 22.5% and 23.6% of which were resistant to imipenem and meropenem, respectively . Most Enterobacterales isolates were highly susceptible to tigecycline, colistin and polymyxin B, with resistance rates ranging from 0.6% to 10.0%. The resistance rate to imipenem and meropenem was 21.9% and 17.4% for Pseudomonas aeruginosa, respectively, and 67.5% and 68.1% for Acinetobacter baumannii, respectively. Conclusions Increasing resistance to the commonly used antimicrobial agents is still observed in clinical bacterial isolates. However, the prevalence of important crabapenem-resistant organisms such as crabapenem-resistant K. pneumoniae, P. aeruginosa, and A. baumannii showed a slightly decreasing trend. This finding suggests that strengthening bacterial resistance surveillance and multidisciplinary linkage are important for preventing the occurrence and development of bacterial resistance.

Objective To investigate the antimicrobial susceptibility of clinical isolates of Corynebacterium striatum and the clinical characteristics of the patients infected or colonized with these strains. Methods The C. striatum strains isolated from clinical specimens were collected in Quanzhou First Hospital Affiliated to Fujian Medical University from July 2020 to September 2022. The clinical data were analyzed to examine the clinical characteristics of patients with C. striatum colonization or infection. The susceptibility of these strains to 18 antimicrobial agents were tested by broth microdilution method. The gyrA gene related to quinolone resistance determining region was amplified and sequenced to analyze the position of amino acid mutations. The ribosomal methylase gene ermX and aminoglycoside enzyme gene aphA1 were amplified by PCR and sequenced. Results Antimicrobial susceptibility testing indicated that all of the 72 strains were susceptible to vancomycin, linezolid and daptomycin. All stains were resistant to ceftriaxone, ciprofloxacin and moxifloxacin. The C. striatum strains showed high resistance rate to penicillin (87.5%), cefepime (95.8%), meropenem (95.8%), trimethoprim-sulfamethoxazole (90.3%), erythromycin (98.6%) and clindamycin (98.6%), but relatively lower resistance rate to gentamycin (25.0%), tetracycline (30.6%) and rifampicin (23.6%). Sequencing analysis indicated that 3 strains of C. striatum had single mutation of gyrA gene (Ser87Val), 67 strains had double mutations (Ser87Phe, Asp91Ala or Ser87Tyr, Asp91Ala) and 2 strains had three point mutations (Ser87Phe, Ala88Pro and Asp91Ala), which was newly identified in this study. The ermX gene was detected in all of the isolates and the prevalence of aphA1 gene was 43.1%. The 72 strains of C. striatum were mainly isolated from ICU (65.2%) and lower respiratory tract specimen (91.6%). The average age of patients was 68.0 ± 15.3 years old. About 72.2% (52/72) of the C. striatum strains were isolated from the patients with infection and 27.8% (20/72) were colonizers. Compared to the patients colonized with C. striatum, the patients with C. striatum infection had statistically significant higher percentages of hospital stay ≥ 28 days, cerebral hemorrhage, disturbance of consciousness and disease deterioration (P < 0.05). Conclusions All of the 72 C. striatum isolates were multidrug resistant, and the outcome of patients with C. striatum infection was relatively poor.

Objective To evaluate the efficacy and safety of the omadacycline-based therapies in patients with community-acquired pneumonia (CAP). Methods The clinical data of CAP patients treated with omadacycline (± β-lactam/β-lactamase inhibitor) in the First Affiliated Hospital of Nanchang University from January to May 2023 were reviewed and analyzed. The patients were assigned to omadacycline alone or omadacycline plus β-lactam/β-lactamase inhibitor treatment group. The clinical efficacy, microbiological efficacy, and drug-related adverse events were summarized and compared between groups. Results A total of 135 adult patients with CAP were enrolled, including 23 (17.04%) patients with chronic liver disease, 25 (18.52%) patients with chronic kidney disease, and 64 (47.41%) patients treated with omadacycline alone. The overall clinical efficacy rate was 81.48% (110/135), specifically 79.69% (51/64) in the patients treated with omadacycline alone and 83.10% (59/71) in the patients treated with omadacycline plus β-lactam/β-lactamase inhibitor. The clinical efficacy rate was 86.36% (38/44) in the patients treated in the general ward. Overall, 21 cases of drug-related adverse events (mainly nausea) were reported in 15 patients, all of which were mild to moderate. Conclusions Omadacycline has shown good therapeutic effect in treatment of CAP in Chinese adults, especially for the patients treated in general ward. Most of the adverse events of omadacycline were mild to moderate and tolerable.

Objective To investigate the antimicrobial susceptibility, resistance mechanisms, and molecular characteristics of clinical isolates of carbapenem-resistant Enterobacterales (CRE) (except Klebsiella pneumoniae) in China. Methods The CRE strains (except K. pneumoniae) were isolated from 151 medical institutions in 31 provinces, municipalities and autonomous regions of China from January to June 2021 and tested in 3 central laboratories. The antimicrobial susceptibility of CRE was determined by broth microdilution method. Whole genome sequencing was performed to analyze the carbapenemase genes and multilocus sequence typing (MLST) of all strains. Results A total of 946 CRE strains were collected, among which Escherichia coli, Enterobacter cloacae and other Enterobacterales accounted for 41.1% (389/946), 34.4% (325/946) and 24.5% (232/946), respectively. Antimicrobial susceptibility testing showed that E. coli, E. cloacae and other Enterobacterales were highly sensitive to aztreonam-avibactam, amikacin, colistin, polymyxin B and tigecycline, and 87.1%-95.5% of the strains were susceptible to these drugs. Whole genome sequencing indicated that bla_NDM-5 (71.7%, 279/389) and bla_NDM-1 (64.3%, 209/325) were the predominant carbapenemase gene types in E. coli and E. cloacae, respectively, while bla_NDM-1 was predominant in C. freundii and K. aerogenes strains, accounting for 73.8% (31/42) and 57.8% (37/64), respectively. Among K. oxytogenes, bla_KPC-2 and bla_NDM-1 accounted for 30.4% (14/46) and 26.1% (12/46), respectively. A total of 87 ST types of E. coli were identified, mainly ST410 (22.1%, 86/389) and ST167 (10.5%, 41/389). ST410 E. coli was mainly isolated in Fujian, Hebei, Hunan, Inner Mongolia and Yunnan provinces, and ST167 E. coli was mainly isolated in Beijing, Hainan, Henan, Liaoning and Qinghai provinces. There were 54 ST types of E. cloacae, mainly ST171 (17.8%, 58/325) and ST78 (7.1%, 23/325). ST171 E. cloacae was mainly found in Anhui, Hebei, Heilongjiang and Henan provinces, while ST78 E. cloacae was mainly found in Hubei, Guangxi and Guizhou provinces. Conclusions Carbapenemase production is the main mechanism underlying carbapenem resistance of Enterobacterales in China. The clonotypes of CRE strains varied with geographic regions of China.

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 analyze the general condition, etiological characteristics, antibiotic use, treatment and prognosis of adult patients with pyogenic liver abscess (PLA) in order to improve the diagnosis and treatment of PLA. Methods The clinical data of adult patients diagnosed with PLA who were hospitalized in Tianjin Medical University General Hospital from December 2019 to December 2022 were retrospectively analyzed, including general information, pathogen culture and antimicrobial susceptibility testing results, treatment and outcomes. The etiological characteristics and the use of clinical anti-infective drugs were analyzed. Results A total of 280 adult patients with PLA were enrolled, including 161 males and 119 females (male/female ratio: 1.35:1). The average age was 63.1 ± 13.6 years. PLA was most frequently found in the patients of 50-80 years of age. The most common route of infection was cryptogenic infection (55.7%). The most common underlying disease was diabetes mellitus (41.1%). The positive rate of bacterial culture was 28.4% from blood, and 80.3% from pus. Klebsiella pneumoniae and Escherichia coli were the most common bacteria isolated from blood culture and pus culture. A total of 14 strains of antibiotic-resistant bacteria were identified, including 3 strains of extended-spectrum β-lactamase (ESBLs)-producing K. pneumoniae, 3 strains of ESBLs-producing E. coli, 1 strain of carbapenem-resistant K. pneumoniae, and 1 strain of carbapenem-resistant E. coli. There were 2 strains of methicillin-resistant Staphylococcus, 3 strains of high level ampicillin and aminoglycoside resistant Enterococcus, and 1 strain of vancomycin-resistant Enterococcus. The gram-negative pathogens showed the lowest susceptibility rate to levofloxacin (82.3%) and the highest susceptibility rate to imipenem (98.2%). Overall, the gram-negative pathogens were generally susceptible to cephalosporins/β-lactamase inhibitor combinations, penicillins/β-lactamase inhibitor combinations, aminoglycosides, glycylcyclines, cephamycins, carbapenems and sulfonamides. Cephalosporins/β-lactamase inhibitor combinations are the most commonly used initial empirical treatment for PLA. Conclusions PLA is more common in men, especially the patients of 50-80 years of age and those complicated with diabetes mellitus. K pneumoniae was the major pathogen, which was sensitive to most commonly used antibiotics. The empirical treatment is mainly cephalosporins/β-lactamase inhibitor combinations. Carbapenems were also used frequently. Attention should be paid to unnecessary combination therapies and irrational use of antibiotics.

Objective To report two cases of meningitis caused by Corynebacterium and review relevant literature to enhance clinical awareness of the pathogenicity of Corynebacterium species. Methods The clinical details were reported for 2 cases of meningitis caused by Corynebacterium. Similar case reports were retrieved from PubMed, CNKI, Wanfang, VIP, and CBM databases using search terms “Corynebacterium meningitis” and “cerebrospinal fluid shunt infection”. Clinical data of the identified patients were reviewed and analyzed. Results Both patients with meningitis caused by Corynebacterium developed symptoms of fever, abdominal pain, and unconsciousness following lumboperitoneal shunt procedures. The culture of cerebrospinal fluid was positive for Corynebacterium. Both patients improved significantly after vancomycin treatment. Literature search yielded 29 similar cases. Overall, the 31 cases (including the two cases in this report) included 20 males and 11 females, aged between 4 weeks to 87 years. The identified Corynebacterium species included C. jeikeium in 12 cases, C. striatum in 9 cases, C. xerosis in 2 cases, C. bovis in 2 cases, C. aquaticum, C. equine, and C. minutissimum one case each, and unspecified Corynebacterium species in 3 cases. Underlying diseases were reporetd in most patients, including immune disorder in 2 cases, malignant tumor in 8 cases, genetic disease in 2 cases, premature with hydrocephalus in 4 cases, brain trauma in 2 cases, intracranial vascular malformation in 2 cases, and cerebral aneurysm in 2 cases. Risk factors for Corynebacterium meningitis included chemotherapy for malignancy in 5 cases, long term use of steroids and immunosuppressants in 2 cases, invasive procedures in 24 cases, and prior antibiotic use in 11 cases. Vancomycin was the most commonly prescribed treatment. The drainage tube and/or venous catheter were also removed or replaced in 19 cases. Twenty-five patients recovered after treatment and 6 patients died. Conclusions Corynebacterium species are emerging as opportunistic pathogens. Clinicians should be aware of the infections caused by Corynebacterium if patients have undergone invasive procedures or are immunocompromised, especially when associated with fever, altered consciousness, and clinical signs of encephalitis/meningitis. If cerebrospinal fluid test is positive for Corynebacterium, specific treatment should be prescribed promptly for Corynebacterium infection.

Objective To understand the changing distribution and antimicrobial resistance profiles of Klebsiella strains in 52 hospitals across China in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021. Methods Antimicrobial susceptibility testing was carried out according to the unified CHINET protocol. The susceptibility results were interpreted according to the breakpoints in the Clinical & Laboratory Standards Institute (CLSI) M100 document. Results A total of 241,549 nonduplicate Klebsiella strains were isolated from 2015 to 2021, including Klebsiella pneumoniae (88.0%), Klebsiella aerogenes (5.8%), Klebsiella oxytoca (5.7%), and other Klebsiella species (0.6%). Klebsiella strains were mainly isolated from respiratory tract (48.49 ±5.32)%. Internal medicine (22.79 ± 3.28)%, surgery (17.98 ± 3.10)%, and ICU (14.03 ± 1.39)% were the top 3 departments where Klebsiella strains were most frequently isolated. K. pneumoniae isolates showed higher resistance rate to most antimicrobial agents compared to other Klebsiella species. Klebsiella isolates maintained low resistance rates to tigecycline and polymyxin B. ESBLs-producing K. pneumoniae and K. oxytoca strains showed higher resistance rates to all the antimicrobial agents tested compared to the corresponding ESBLs-nonproducing strains. The K. pneumoniae and carbapenem-resistant K. pneumoniae (CRKP) strains isolated from ICU patients demonstrated higher resistance rates to majority of the antimicrobial agents tested than the strains isolated from non-ICU patients. The CRKP strains isolated from adult patients had higher resistance rates to most of the antimicrobial agents tested than the corresponding CRKP strains isolated from paediatric patients. Conclusions The prevalence of carbapenem-resistant strains in Klebsiella isolates increased greatly from 2015 to 2021. However, the Klebsiella isolates remained highly susceptible to tigecycline and polymyxin B. Antimicrobial resistance surveillance should still be strengthened for Klebsiella strains.

Objective To examine the possible factors affecting the attainment of target serum trough concentration of vancomycin in premature newborns for optimization of clinical dosing regimens. Methods The vancomycin trough concentration data were collected retrospectively from preterm newborns who received intravenous infusion of vancomycin from December 2016 to March 2021. According to the Evidence-based Guideline for Therapeutic Drug Monitoring of Vancomycin: 2020 Update by the Division of Therapeutic Drug Monitoring, Chinese Pharmacological Society, the patients were assigned to failure (< 5 mg/L) or success (5-15 mg/L) in target attainment, or beyond target group (> 15 mg/L) base on vancomycin trough concentration. Statistical software SPSS was used to analyze differences in clinical characteristics between different groups, and profile various factors that may affect attainment of target serum trough concentration of vancomycin. Results The median (interquartile range) trough concentration of vancomycin was 12.50 (7.95-18.05) mg/L in 82 preterm newborns. The target trough concentration of vancomycin was attained in 47 preterm newborns (57.32%), and the corresponding trough concentration of vancomycin was 10.90 (7.80-13.30) mg/L. The trough concentration of vancomycin was beyond target in 27 preterm newborns (32.93%). The corresponding median trough concentration of vancomycin was 21.80 (18.00-23.80) mg/L. Serum trough concentration of vancomycin failed to achieve the target in only 8 preterm newborns (9.75%). The corresponding median trough concentration was 4.10 (2.48-4.60) mg/L.Univariate analysis showed that there were statistically significant differences (P < 0.05) in postmenstrual age and current weight between the patients succeeded in attaining target trough concentration and those who failed to attain the target. Baseline serum creatinine and dosing interval showed statistically significant differences (P < 0.01) between the newborns who attained the target concentration and those with higher trough concentration beyond the target. Multivariate regression analysis showed that baseline serum creatinine (OR = 1.063, 95% CI 1.024-1.102, P = 0.001, cutoff: 62 μmol/L) and dosing interval (OR = 6.693, 95% CI 1.604-27.920, P = 0.009) were independent risk factors for excessively high vancomycin trough concentrations. Conclusions The dosing regimens as recommended in the current package insert only enable the attainment of target serum trough concentration of vancomycin in half of the premature newborns. The dosing regimen of vancomycin should be optimized by taking postmenstrual age, current weight, baseline serum creatinine and dosing interval into account. Therapeutic drug monitoring is necessary to ensure safety and effectiveness.

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 understand the distribution and drug resistance profiles of common clinical isolates in the intensive care unit (ICU) of a hospital in Xi’an. Methods A retrospective analysis was conducted on the antimicrobial susceptibility test results of clinical bacterial isolates in ICU of the Second Affiliated Hospital of Xi’an Jiaotong University from January 1, 2020 to December 31, 2022. Results A total of 3 649 clinical isolates were isolated from the ICU, including 1 344 (36.8%) strains of Gram-positive bacteria and 2 305 (63.2%) strains of Gram-negative bacteria. The most common bacterial species were Klebsiella spp. (14.8%, 540/3 649), Enterococcus spp. (14.3%, 522/3 649), coagulase-negative Staphylococcus (12.3%, 448/3 649), Acinetobacter spp. (12.0%, 438/3 649), and Escherichia coli (11.6%, 424/3 649). The prevalence of methicillin-resistant Staphylococcus aureus (MRSA), methicillin-resistant Staphylococcus epidermidis (MRSE), and methicillin-resistant coagulase-negative Staphylococcus (MRCNS) was 76.1%, 82.4%, and 69.9%, respectively. MRSA, MRSE, and MRCNS strains showed significantly higher antimicrobial resistance rates than MSSA, MSSE, and MSCNS except for trimethoprim-sulfamethoxazole. No Staphylococcus strains were found resistant to vancomycin or linezolid. Enterococcus faecium demonstrated higher antimicrobial resistance rates than Enterococcus faecalis. No Enterococcus isolates were found resistant to vancomycin. Two strains of linezolid-resistant E. faecalis were identified. Klebsiella pneumoniae showed high resistance rates to imipenem and meropenem (38.4% and 40.2%, respectively). Less than 2.0% of the Escherichia coli strains were resistant to imipenem and meropenem, while more than 10.0% of the Enterobacter cloacae were resistant to imipenem and meropenem. About 27.1% and 19.6% of the Pseudomonas aeruginosa strains were resistant to imipenem and meropenem, respectively. Acinetobacter baumannii showed high resistance rates to imipenem and meropenem (86.0% and 86.7%, respectively). Conclusions K. pneumoniae and A. baumannii strains isolated from the intensive care unit showed high resistance rates to carbapenems. Other species of Enterobacterales are still susceptible to carbapenems at a low resistance rate. Linezolid-resistant strain was identified in Enterococcus spp. No cross resistance to vancomycin was found in Enterococcus isolates. Therefore, it is necessary to strengthen the surveillance of antimicrobial resistance and use antibiotics reasonably for controlling hospital infections.

Objective To investigate the relationship between the levels of CD4⁺/CD8⁺ and D-dimer (D-D) in peripheral blood and the outcome of Epstein-Barr virus-associated hemophagocytic lymphohistiocytosis (EBV-HLH). Methods Ninety patients with EBV-HLH who were treated in Beijing Friendship Hospital from September 2021 to August 2023 were included as observation group, and additional 90 patients with infectious mononucleosis (IM) treated in the hospital contemporarily were selected as the control group. The levels of CD4⁺/CD8⁺ and D-D in peripheral blood were compared between the two groups of patients to examine the correlation between the levels of CD4⁺/CD8⁺ and D-D in peripheral blood and EBV-DNA load in patients with EBV-HLH, compare the outcome of patients within 3 months in terms of the levels of CD4⁺/CD8⁺ and D-D in peripheral blood, evaluate the effects of CD4⁺/CD8⁺ and D-D levels in peripheral blood on the risk of death from EBV-HLH, and analyze the interaction between the levels of CD4⁺/CD8⁺ and D-D in peripheral blood. Results The patients in observation group showed significantly lower peripheral blood CD4⁺/CD8⁺ ratio and significantly higher D-D than the patients in control group (P < 0.05). The peripheral blood CD4⁺/CD8⁺ ratio was negatively correlated with EBV-DNA load (P < 0.05), and D-D was positively correlated with EBV-DNA load (P < 0.05) in EBV-HLH patients. The patients with high peripheral blood CD4⁺/CD8⁺ ratio were assocaited with lower 3-month mortality rate compared to the patients with low CD4⁺/CD8⁺ ratio. The patients with high D-D level were associated with higher 3-month mortality rate compared to the patients with low D-D level (P < 0.05). In EBV-HLH patients with low levels of peripheral blood CD4⁺/CD8⁺, the risk of death was 6.125 times that of the patients with high levels of CD4⁺/CD8⁺. High level D-D was associated with 14.348 times risk of death compared to the patients with low level D-D. CD4⁺/CD8⁺ and D-D had synergistic effect on death of EBV-HLH patients. Conclusions Peripheral blood CD4⁺/CD8⁺ levels decreased and D-D levels increased in EBV-HLH patients. Peripheral blood CD4⁺/CD8⁺ levels and D-D levels and their changes may be useful for predicting the outcome of patients.

Objective To investigate the changing distribution and antibiotic resistance profiles of clinical isolates of Staphylococcus in hospitals across China from 2015 to 2021. Methods Antimicrobial susceptibility testing was conducted for the clinical isolates of Staphylococcus according to the unified protocol of CHINET (China Antimicrobial Surveillance Network) using disk diffusion method and commercial automated systems. The CHINET antimicrobial resistance surveillance data from 2015 to 2021 were interpreted according to the 2021 CLSI breakpoints and analyzed using WHONET 5.6. Results During the period from 2015 to 2021, a total of 204,771 nonduplicate strains of Staphylococcus were isolated, including 136,731 (66.8%) strains of Staphylococcus aureus and 68,040 (33.2%) strains of coagulase-negative Staphylococcus (CNS). The proportions of S. aureus isolates and CNS isolates did not show significant change. S. aureus strains were mainly isolated from respiratory specimens (38.9 ± 5.1)%, wound, pus and secretions (33.6 ± 4.2)%, and blood (11.9 ± 1.5)%. The CNS strains were predominantly isolated from blood (73.6 ± 4.2)%, cerebrospinal fluid (12.1 ± 2.5)%, and pleural effusion and ascites (8.4 ± 2.1)%. S. aureus strains were mainly isolated from the patients in ICU (17.0 ± 7.3)%, outpatient and emergency (11.6 ± 1.7)%, and department of surgery (11.2±0.9)%, whereas CNS strains were primarily isolated from the patients in ICU (32.2 ± 9.7)%, outpatient and emergency (12.8 ± 4.7)%, and department of internal medicine (11.2 ± 1.9)%. The prevalence of methicillin-resistant strains was 32.9% in S. aureus (MRSA) and 74.1% in CNS (MRCNS). Over the 7-year period, the prevalence of MRSA decreased from 42.1% to 29.2%, and the prevalence of MRCNS decreased from 82.1% to 68.2%. MRSA showed higher resistance rates to all the antimicrobial agents tested except trimethoprim-sulfamethoxazole than methicillin-susceptible S. aureus (MSSA). Over the 7-year period, MRSA strains showed decreasing resistance rates to gentamicin, rifampicin, and levofloxacin, MRCNS showed decreasing resistance rates to gentamicin, erythromycin, rifampicin, and trimethoprim-sulfamethoxazole, but increasing resistance rate to levofloxacin. No vancomycin-resistant strains were detected. The prevalence of linezolid-resistant MRCNS increased from 0.2% to 2.3% over the 7-year period. Conclusions Staphylococcus remains the major pathogen among gram-positive bacteria. MRSA and MRCNS were still the principal antibiotic-resistant gram-positive bacteria. No S. aureus isolates were found resistant to vancomycin or linezolid, but linezolid-resistant strains have been detected in MRCNS isolates, which is an issue of concern.

Objective To monitor the antifungal resistance of clinical isolates of Candida spp. in the East China region. Methods MALDI-TOF MS or molecular methods were used to re-identify the strains collected from January 2018 to December 2022. Antifungal susceptibility testing was performed using the broth microdilution method. The susceptibility test results were interpreted according to the breakpoints of 2022 Clinical and Laboratory Standards Institute (CLSI) documents M27 M44s-Ed3 and M57s-Ed4. Results A total of 3 026 strains of Candida were collected, 65.33% of which were isolated from sterile body sites, mainly from blood (38.86%) and pleural effusion/ascites (10.21%). The predominant species of Candida were Candida albicans (44.51%), followed by Candida parapsilosis complex (19.46%), Candida tropicalis (13.98%), Candida glabrata (10.34%), and other Candida species (0.79%). Candida albicans showed overall high susceptibility rates to the 10 antifungal drugs tested (the lowest rate being 93.62%). Only 2.97% of the strains showed dose-dependent susceptibility (SDD) to fluconazole. Candida parapsilosis complex had a SDD rate of 2.61% and a resistance rate of 9.42% to fluconazole, and susceptibility rates above 90% to other drugs. Candida glabrata had a SDD rate of 92.01% and a resistance rate of 7.99% to fluconazole, resistance rates of 32.27% and 48.24% to posaconazole and voriconazole non-wild-type strains (NWT), respectively, and susceptibility rates above 90% to other drugs. Candida tropicalis had resistance rates of 29.55% and 26.24% to fluconazole and voriconazole, respectively, resistance rates of 76.60% and 21.99% to posaconazole and echinocandins non-wild-type strains (NWT), and a resistance rate of 2.36% to echinocandins. Conclusions The prevalence and species distribution of Candida spp. in the East China region are consistent with previous domestic and international reports. Candida glabrata exhibits certain degree of resistance to fluconazole, while Candida tropicalis demonstrates higher resistance to triazole drugs. Additionally, echinocandins resistance has emerged in Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis.

Objective To examine the compliance of and factors affecting target attainment of serum trough concentration of norvancomycin in ICU patients, and the effects of different trough concentrations on clinical efficacy and renal impairment. Methods Adult patients admitted to the Department of Critical Care Medicine of Huangshan People’s Hospital and receiving intravenous infusion of norvancomycin from January 2020 to December 2022 were included. The dosing regimens and steady-state trough concentrations of norvancomycin were analyzed. The clinical efficacy and renal impairment were compared between different trough concentration levels. The compliance of trough concentration in critically ill patients with different renal functions was examined. Logistic regression analysis was performed to profile the factors possibly affecting the trough concentration of norvancomycin. Results A total of 97 patients were included. The target serum trough concentration (10-20 mg/L) was reached in only 33.0% (32/97) of the critically ill patients. The serum trough concentration was below the target in 51.5% (50/97) of the patients, above the target in 15.5% of the patients. The clinical cure rate and incidence of renal impairment were significantly different among the three groups of patients with different trough concentrations (P < 0.05). The compliance with target serum trough concentration varied with different renal function tests (P < 0.05). Augmented renal clearance and normal renal function were associated with trough concentrations lower than the target. As renal dysfunction got worse, serum trough concentration was more probably higher than the target (P < 0.05). Univariate analysis showed that daily dose, age, gender, height, weight, body mass index (BMI), APACHE II score, sequential organ failure assessment (SOFA) score, blood creatinine, urea nitrogen, procalcitonin, concomitant septic shock, and use of norepinephrine were significantly correlated with trough concentrations of norvancomycin (P < 0.05). Multivariate logistic regression analysis indicated that age, SOFA score, blood urea nitrogen, gender, and norepinephrine use were independent factors affecting the serum trough concentration of norvancomycin (P < 0.05). Conclusions The serum trough concentration of norvancomycin varied with renal function states in ICU patients. It is difficult to achieve the steady-state target trough concentration (10-20 mg/L). The clinical cure rate is lower when the trough concentration is lower than the target. As the trough concentration increases, the incidence of renal impairment increases. Age, SOFA score, urea nitrogen, gender, and norepinephrine use are independent factors affecting the serum trough concentrations of norvancomycin.

Objective To investigate the distribution and antimicrobial resistance of clinical isolates in the First Affiliated Hospital of Xi'an Jiaotong University in 2022 for rational use of antibiotics in clinical practice. Methods Nonduplicate clinical isolates were collected from January 1, 2022 to December 31, 2022. Antimicrobial susceptibility testing was carried out using Kirby-Bauer method and automated systems. The data were analyzed using WHONET 5.6 software and interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition). Results Of the 8 638 clinical isolates, gram negative bacteria and gram positive bacteria accounted for 60.8% (5 253/8 638) and 39.2% (3 385/8 638), respectively. The prevalence of methicillin-resistant strains was 33.0% in S. aureus (MRSA), 75.8% in S. epidermidis (MRSE), and 51.9% in other coagulase-negative Staphylococcus (MRCNS). No staphylococcal strains were found resistant to vancomycin. The prevalence of vancomycin-resistant E. faecium was 0.6%, and no vancomycin-resistant E. faecalis was found. E. faecalis strains showed higher resistance rate to linezolid (5.2%) than E. faecium (0.7%). The prevalence of carbapenem-resistant Enterobacterales (CRE) was 7.9%, specifically 12.1% for carbapenem-resistant K. pneumoniae (CRKP) and 1.6% for carbapenem-resistant E. coli (CREC). The prevalence of carbapenem-resistant P. aeruginosa (CRPA) and carbapenem-resistant A. baumannii (CRAB) was 30.9% and 77.0%, respectively. Conclusions Clinical microbiology laboratories should strengthen the collection and testing of clinical specimens from the sites of infection in order to improve pathogenic diagnosis and antimicrobial resistance surveillance. This is conducive to the rational use of antibiotics and reduce the further spread of multidrug-resistant bacteria.

Objective To summarize the clinical characteristics of delayed diagnosis of tuberculosis in children, analyze the risk factors of delayed diagnosis, and support early diagnosis of tuberculosis in children. Methods This is a retrospective analysis based on the clinical data of tuberculosis patients admitted to the Children's Hospital Affiliated to Zhengzhou University from January 2015 to February 2023. The clinical characteristics of children were analyzed in terms of age group. According to the definition of diagnosis delay, the patients were assigned to delayed group and non-delayed group. Univariate analysis and multivariate logistic regression were used to analyze the risk factors for diagnosis delay. Results A total of 82 children with tuberculosis were included (46 cases in delayed diagnosis group and 36 cases in non-delayed diagnosis group). The rate of diagnosis delay was 56.1%. The incidence of acute miliary pulmonary tuberculosis and tuberculous meningitis was significantly higher in children ≤5 years old than that in children > 5 years old (P < 0.05). Diagnosis delay was associated with significantly higher prevalence of chronic fever, cough > 2 weeks, growth retardation and significantly longer duration of empirical antibiotic use compared to the children without diagnosis delay (P < 0.05). Univariate analysis showed that patient origin, contact history, mixed infection, tuberculosis type, molecular biological assay and severe disease were related to the delay of TB diagnosis (P < 0.05). Multivariate logistic regression analysis showed that patient origin [≥3 clinic visits (OR = 7.064, 95% CI: 1.677-29.754)], mixed infection (OR = 3.812, 95% CI: 1.185-12.260), severe disease (OR = 3.697, 95% CI: 1.081-12.646)] were risk factors for diagnosis delay in children. Molecular biological assay (OR = 4.642, 95% CI: 1.318-16.345) was a protective factor. Conclusions The clinical symptoms of tuberculosis in children are atypical. Delayed diagnosis of tuberculosis is common. Multiple clinic visits, mixed infection, and severe disease are the risk factors for diagnosis delay. Tuberculosis should be taken into account for the children with chronic fever, cough and growth retardation who have failed to respond to adequate therapy with third-generation cephalosporin and carbapenems. Molecular biological assay is helpful for early diagnosis of tuberculosis in children with negative sputum smear.

Objective To investigate the distribution and antimicrobial resistance of the bacterial strains isolated from blood samples of inpatients in Longgang Hospital, Beijing University of Chinese Medicine. Methods The bacterial identification and antimicrobial susceptibility test results for the strains isolated from 2018 to 2022 were retrospectively analyzed. Results A total of 910 strains of bacteria were isolated from blood samples, of which 63.2% (575/910) were gram-negative bacteria and 36.8% (335/910) were gram-positive bacteria. Escherichia coli, coagulase-negative Staphylococcus, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus spp. were the top 5 pathogens. In the past 5 years, no carbapenem-resistant strains of E. coli or K. pneumoniae were found in the blood samples of the inpatients. A. baumannii had a resistance rate of 11.8% to carbapenems. The prevalence of methicillin-resistant strains in S. aureus, S. epidermidis and other Staphylococcus species was 16.7%, 75.0% and 55.5%, respectively. No vancomycin- or linezolid-resistant staphylococcual isolates were found. No strains of Enterococcus faecalis or Enterococcus faecium were found resistant to high concentrations of gentamicin, linezolid, or vancomycin. Conclusions The bacteria isolated from blood samples in Longgang Hospital were mainly gram-negative bacteria. Carbapenem-resistant strain was identified in the strains of A. baumannii. Bacterial resistance surveillance should be strengthened for the isolates from blood samples and other specimens from the site of infection. Antimicrobial agents should be used rationally to prevent the spread of drug-resistant bacteria.

Objective To investigate the distribution and antimicrobial resistance of bacterial isolates from blood samples in the hospitals participating in China Antimicrobial Surveillance Network (CHINET) from 2015 to 2021. Methods Bacterial strains isolated from blood samples were collected from 52 medical centers participating in CHINET from 2015 to 2021 for analysis of bacetrial distribution and antimicrobial resistance. Results A total of 153 591 isolates were collected, 48.8% of which were gram-positive bacteria and 51.2% were gram-negative bacteria. The top five bacterial strains were coagulase negative Staphylococcus (28.2%), Escherichia coli (20.7%), Klebsiella (13.7%), Enterococcus (7.2%), and Staphylococcus aureus (6.6%). Compard to female patients, male patients showed lower proportion of E. coli and higher proportions of other bacterial species in all the bacterial isolaets from blood samples. The proportions of Streptococcus pneumoniae and Salmonella in all the bacterial isolaets from blood samples were higher in children compared to adults. Enterobacterales species showed various resistance rates to antimicrobial agents. Overall, ≥58.0%, ≥36.8% and ≥56.8% of E. coli strains were resistant to cefotaxime, gentamicin and levofloxacin respectively over the 7-year period. However, less than 2.5% of the E. coli strains were resistant to carbapenems. K. pneumoniae showed higher resistance rates to imipenem and meropenem than other Enterobacterales species. During the 7-year period, the prevalence of imipenem-resistant and meropenem-resistant K. pneumoniae increased from 21.4% and 19.9% in 2015 to 25.7% and 26.6% in 2021, respectively. However, carbapenems still maintained good antibacterial activity against other Enterobacterales, associaetd with lower resistance rates. In the 7-year period, Acinetobacter baumannii showed a dwonward trend in the resistance rates to imipenem and meropenem, but remained 72.9% and 73.2% respectively in 2021. The prevalence of imipenem-resistant and meropenem-resistantP. aeruginosa decreased from 26.7% and 22.9% in 2015 to 18.5% and 14.7% in 2021, respectively. The prevalence of PRSP was 1.5% in the isolaets from adults and and 0.8% in the isolates from children. Less than 3.0% of the Enterococcus faecium and Enterococcus faecalis strains were resistant to vancomycin, teicolanin, or linezolid. The prevalence of methicillin-resistant S. aureus (MRSA) and coagulase negative Staphylococcus (MRCNS) was 32.1% and 81.0%, respectively. The prevalence of MRSA was relatively stable, 28.5% in 2015 and 28.0% in 2021. Conclusions Coagulase negative Staphylococcus, E. coli and K. pneumoniae were the main bacterial species isolated from blood samples in the hospitals participaing in the CHINET from 2015 to 2021. Significant sex and age differences were found in the distribution of bcterial isolates from blood samples. The overall resistance rates of the top bacetrial strains from blood samples to antimicrobial agents showed a downward trend. Ongoing surveillance of antimicrobial resistance for the isolates from blood samples is still essential for prescribing rational antimicrobial therapies and curbing bacterial resistance.

Objective To analyze the changing prevalence and resistance profiles of multiple drug-resistant (MDR) bacteria in Minhang Hospital of Fudan University before and after the onset of COVID-19 pandemic. Methods The resistance profiles of 6 bacterial species were compared before (2017-2019) and after (2020-2022) the onset of COVID-19 pandemic. WHONET 5.6 software was used to statistically analyze the data of antimicrobial susceptibility testing. Results After the onset of COVID-19 (2020-2022), the prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP) was significantly higher than that in the pre-pandemic period (2017-2019) (40.1% vs 27.9%, P < 0.01), while the prevalence of carbapenem-resistant Escherichia coli (CREC) decreased significantly (1.9% vs 3.1%, P < 0.05). The prevalences of carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus (VRE) did not show significant difference before and after the onset of COVID-19 pandemic. MDR isolates were mainly isolated from respiratory tract samples either before or after COVID-19 pandemic (78.4% vs 78.5%). The prevalence of MDR in the intensive care unit (ICU) was significantly higher during the period from 2020 to 2022 compared to the pre-pandemic period (53.1% vs 35.5%, P < 0.01). The resistance rate of MRSA to methoprim-sulfamethoxazole decreased from 15.7% during 2017-2019 to 3.5% during 2020-2022 (P < 0.01). Compared to the pre-pandemic period, the E. faecalis strains showed lower resistance rates to penicillin G, ampicillin, and levofloxacin during 2020-2022. The resistance rate of E. faecium to high-level gentamicin decreased significantly from 50.1% during 2017-2019 to 39.2% during 2020-2022 (P < 0.01). The resistance rate of E. coli to imipenem decreased from 2.7% to 1.2% (P < 0.01), while A. baumannii and P. aeruginosa strains showed stable resistance rates to carbapenems (P > 0.05). Conclusions After the onset of COVID-19 pandemic, the prevalence of CREC decreased significantly. The prevalences of CRAB, CRPA, MRSA, and VRE also showed a decreasing trend. However, the prevalence and resistance rates of CRKP significantly increased. It is necessary to strengthen hospital infection control measures to curb the spread of MDR bacteria.

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 understand the changing distribution and antimicrobial resistance profiles of Proteus, Morganella and Providencia in hospitals across China from January 1, 2015 to December 31, 2021 in the CHINET Antimicrobial Resistance Surveillance Program. Methods Antimicrobial susceptibility testing was carried out following the unified CHINET protocol. The results were interpreted in accordance with the breakpoints in the 2021 Clinical & Laboratory Standards Institute (CLSI) M100 (31st Edition). Results A total of 32 433 Enterobacterales strains were isolated during the 7-year period, including 24 160 strains of Proteus, 6 704 strains of Morganella, and 1 569 strains of Providencia. The overall number of these Enterobacterales isolates increased significantly over the 7-year period. The top 3 specimen source of these strains were urine, lower respiratory tract specimens, and wound secretions. Proteus, Morganella, and Providencia isolates showed lower resistance rates to amikacin, meropenem, cefoxitin, cefepime, cefoperazone-sulbactam, and piperacillin-tazobactam. For most of the antibiotics tested, less than 10% of the Proteus and Morganella strains were resistant, while less than 20% of the Providencia strains were resistant. The prevalence of carbapenem‐resistant Enterobacterales (CRE) was 1.4% in Proteus isolates, 1.9% in Morganella isolates, and 15.6% in Providencia isolates. Conclusions The overall number of clinical isolates of Proteus, Morganella and Providencia increased significantly in the 7-year period from 2015 to 2021. The prevalence of CRE strains also increased. More attention should be paid to antimicrobial resistance surveillance and rational antibiotic use so as to prevent the emergence and increase of antimicrobial resistance.