BACKGROUND:This study aims to evaluate the effect of intrathecal (IT) administration of antituberculosis agents on functional outcomes in patients with tuberculous meningitis (TBM) and to explore its potential as a strategy to overcome the blood-brain barrier. METHODS:We retrospectively analyzed TBM patients admitted between 2012 and 2023 at Hangzhou Red Cross Hospital and Shanghai Public Health Clinical Center. Clinical data were collected during hospitalization, and functional outcomes were assessed at 3-6 months after discharge using the modified Rankin Scale (mRS). Propensity score matching (PSM) was applied to balance baseline characteristics between patients who received IT therapy and those who did not. Treatment effects were compared using the Mann-Whitney U test. RESULTS:A total of 533 patients with TBM were included. After PSM, 72 patients receiving IT therapy were compared with 121 matched controls. Intrathecal therapy was associated with significantly lower mRS scores at discharge compared with controls (P = .0012), suggesting that it may improve functional outcomes. CONCLUSIONS:Intrathecal administration of isoniazid and dexamethasone may improve functional prognosis in TBM patients. These findings highlight IT therapy as a promising approach to circumvent the blood-brain barrier and warrant validation in multicenter randomized controlled trials.

ObjectiveThis study aimed to establish tentative epidemiological cutoff values (TECOFFs) for faropenem against Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Haemophilus influenzae, and Streptococcus pneumoniae based on minimum inhibitory concentration (MIC) distributions.MethodsA total of 2,032 bacterial isolates were collected from Peking University First Hospital, Peking Union Medical College Hospital, Huashan Hospital affiliated with Fudan University, and Sir Run Run Shaw Hospital affiliated with Zhejiang University School of Medicine between 2019 and 2021. The susceptibility of these bacteria to faropenem was determined using the broth microdilution and disk diffusion methods in the clinical microbiology laboratories of these four hospitals. To establish wild-type TECOFFs for faropenem, isolates susceptible to ertapenem for E. coli and K. pneumoniae, those susceptible to oxacillin for S. aureus, and those with unscreened susceptibility for H. influenzae and S. pneumoniae were regarded as wild-type strains.ResultsThe MIC TECOFF for faropenem against E. coli was determined to be 2 mg/L, with MIC ≤2 mg/L indicating wild-type strains and MIC ≥4 mg/L indicating non-wild-type strains. The corresponding inhibition zone diameter TECOFF for E. coli was 19 mm, where an inhibition zone diameter ≤18 mm indicates non-wild-type strains and ≥19 mm indicates wild-type strains. For K. pneumoniae, the MIC TECOFF was also 2 mg/L, with similar cutoffs established for the inhibition zones. The MIC TECOFF for faropenem against S. aureus was 0.25 mg/L, for H. influenzae was 1 mg/L, and for S. pneumoniae was 2 mg/L. The corresponding inhibition zone diameter ECOFF for faropenem against S. aureus was 31 mm, for H. influenzae was 14 mm, and for S. pneumoniae was 33 mm.ConclusionThe TECOFFs for faropenem against the tested bacteria were established. These data are useful for clinical microbiologists and clinicians in the interpretation of the results of faropenem susceptibility testing.

BACKGROUND:Paediatric tuberculosis (TB), particularly drug-resistant TB (DR-TB), is associated with significant mortality. However, the global burden of childhood TB remains poorly understood. METHODS:We analysed incident cases, deaths, and age-standardised incidence and mortality rates among children (0-14 years) with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) and extensively drug-resistant tuberculosis (XDR-TB) using the Global Burden of Disease (GBD) 2021 database. Data were stratified by age, sex, region, country, and HIV/AIDS status. Annual and average annual percentage changes were assessed using joinpoint regression analysis. Secondary analyses compared adult and paediatric TB trends in the End TB era and evaluated the potential impact of the COVID-19 pandemic on childhood TB. Sensitivity analyses were performed using the recently released GBD 2023 database. RESULTS:In 2021, an estimated 32 515 (95% UI: 20 968-51 288) paediatric MDR/RR-TB incident cases and 1193 (806-1814) XDR-TB cases occurred globally, with 5887 (2467-11 332) and 253 (109-508) corresponding deaths, respectively; all estimates were lower than counterfactual projections for 2021 in the absence of COVID-19. Since 2005, age-standardised incidence and mortality rates for MDR/RR-TB and mortality rate for XDR-TB have slowly trended downwards, while their proportional contributions to total incident cases and deaths have increased. Children who are female, younger, from low sociodemographic regions, and HIV-coinfected are disproportionately affected. No significant impact of the End TB Strategy on paediatric TB trends was observed after 2015. Cross-dataset comparisons showed concordant principal findings. CONCLUSIONS:The global burden of paediatric DR-TB is substantial, with marked disparities across vulnerable populations and regions. Targeted intervention should be tailored to strategically address regional development status, HIV prevalence, and local health policies.

Objectives:This study comprehensively evaluates the in vitro antibacterial activity of eravacycline against a wide range of significant Gram-negative and Gram-positive bacteria collected across China. Methods:A total of 1250 non-duplicate clinical isolates representing 12 genera and 21 species were collected from 40 hospitals between 2017 and 2019 across China. Minimal inhibitory concentrations were determined using the broth microdilution method in accordance with the standards set by the Clinical and Laboratory Standards Institute. Results:Eravacycline demonstrated potent in vitro activity against most tested bacterial species. The MIC90 values ranged from 0.25 to 2 mg/L for Enterobacterales, except for Proteus vulgaris (4 mg/L). According to the FDA breakpoints, Escherichia coli and Klebsiella pneumoniae exhibited susceptibility rates of 98.9% and 70.9%, respectively. Eravacycline achieved an MIC90 value of 1 mg/L against Acinetobacter baumannii, which was the lowest among all agents tested. For Gram-positive isolates, eravacycline displayed MIC90 values of 0.5 mg/L for MRSA and methicillin-resistant CoNS (MRCNS), 0.03 mg/L for vancomycin-resistant Enterococcus faecium and 0.03 mg/L for Streptococcus pneumoniae, surpassing or equalling tigecycline and markedly outperforming doxycycline. Conclusions:This large-scale multicentre surveillance study demonstrated that eravacycline exhibited potent in vitro activity against major multidrug-resistant Gram-negative and Gram-positive pathogens, indicating that it could be a promising therapeutic option for treating infections caused by these strains.

Abstract This study assessed the antimicrobial susceptibility of clinical bacterial isolates collected from Chinese medical institutions in 2025. Antimicrobial susceptibility testing was performed on isolates from 80 hospitals using disk diffusion or commercial automated systems in accordance with the standardized China Antimicrobial Surveillance Network (CHINET) surveillance protocol. Results were interpreted using the 2025 Clinical and Laboratory Standards Institute breakpoints. Between January and December 2025, 516,309 clinical isolates were included, comprising 28.5% Gram-positive and 71.5% Gram-negative bacteria. The detection rates of methicillin-resistant strains among Staphylococcus aureus , Staphylococcus epidermidis , and other coagulase-negative staphylococci were 28.4%, 80.8%, and 76.5%, respectively, with no vancomycin-resistant strains identified. Vancomycin resistance among Enterococcus faecium isolates was 8.4%, and resistance to most antimicrobial agents was higher than that among Enterococcus faecalis isolates. Among nonmeningeal Streptococcus pneumoniae isolates from pediatric and adult patients, the respective detection rates of penicillin-nonsusceptible strains, comprising penicillin-intermediate S. pneumoniae and penicillin-resistant S. pneumoniae , were low at 3.9% and 5.9%. Except for Klebsiella spp., which showed resistance rates of 20.1% to imipenem and 20.8% to meropenem, resistance among other Enterobacterales was generally below 15.0%. After excluding intrinsically resistant genera, Enterobacterales remained highly susceptible to tigecycline and colistin, with resistance rates of ≤ 6.8%. Resistance rates to imipenem and meropenem were 22.6% and 18.8%, respectively, in Pseudomonas aeruginosa, and 72.0% and 71.9%, respectively, in Acinetobacter baumannii . Antimicrobial resistance among clinical isolates from major regions of China remained a serious concern in 2025. These surveillance findings should inform rational antimicrobial selection and support efforts to limit the emergence and spread of resistance.

BACKGROUND:Cefiderocol is a siderophore cephalosporin with potent, broad spectrum of activity against carbapenem-resistant (CR) Gram-negative bacteria. The objective of this surveillance study was to assess cefiderocol susceptibility in molecularly characterized CR Gram-negative pathogens collected from hospitalized patients across China. METHODS:Susceptibility testing was performed by the broth microdilution method according to Clinical and Laboratory Standards Institute guidelines, using pre-prepared frozen 96-well microtiter Thermo Fisher plates. Susceptibilities to cefiderocol and most comparators were determined by Clinical and Laboratory Standards Institute breakpoints, to tigecycline by US Food and Drug Administration breakpoints, and to colistin by European Committee on Antimicrobial Susceptibility Testing criteria. Carbapenemases were identified by whole-genome sequencing and polymerase chain reaction. RESULTS:Of 149 CR Klebsiella pneumoniae, 95.3% were susceptible to cefiderocol (OXA-48-positive 100% [n = 15]; IMP-positive 100% [n = 9]; KPC-positive 95.4% [n = 108]; NDM-positive 88.2% [n = 17]) and against 103 NDM-positive CR Escherichia coli, cefiderocol susceptibility was 45.6%. Among comparator antibiotics, ceftazidime-avibactam was only active against K. pneumoniae carbapenemase-positive and OXA-48-positive K. pneumoniae isolates. Susceptibilities to tigecycline and colistin were between 22.2% and 97.1% and between 88.2% and 100% across CR Enterobacterales with different carbapenemases, respectively. High cefiderocol susceptibility rates were found for CR Pseudomonas aeruginosa (98.4%), CR Acinetobacter baumannii (99.6%), and Stenotrophomonas maltophilia (99.6%). Among comparator antibiotics, only colistin showed high activity against CR P. aeruginosa (99.2%) and CR A. baumannii (99.2%). CONCLUSIONS:Cefiderocol susceptibility rates were ≥88% against a collection of carbapenemase-positive CR Gram-negative isolates, except for lower susceptibility in NDM-positive CR E. coli isolates. Continuous monitoring of cefiderocol susceptibility is warranted.

OBJECTIVE:To monitor the trends of carbapenem-resistant gram-negative bacteria to antimicrobial agents in healthcare facilities in major regions of China between 2015 and 2024. METHODS:Carbapenem-resistant gram-negative isolates from 74 hospitals in the country were tested for antimicrobial susceptibility using an automated method (imported or domestic AST instruments) supplemented by the disc diffusion method. Results were evaluated using the 2024 CLSI breakpoint. RESULTS:A total of 339 513 clinical isolates were collected between 2015 and 2024. Among clinical Enterobacterales isolates, the rate of carbapenem resistance was generally below 13%, except for Klebsiella spp., where it ranged from 20.4% to 21.9%. Most clinical Enterobacterales isolates are highly susceptible to tigecycline, colistin, and polymyxin B, with resistance rates ranging from 0.1% to 15.4%. The detection rate of meropenem-resistant Pseudomonas aeruginosa has decreased over six consecutive years, from 31.4% in 2018 to 21.5% in 2024. The detection rate of meropenem-resistant Acinetobacter baumannii remained modest, from 64.9% in 2015 to 68.3% in 2024. CONCLUSIONS:Multidrug-resistant bacteria remain a significant challenge in clinical anti-infective treatment, and the surveillance of bacterial resistance and the rational use of antimicrobial agents need to be further strengthened to combat bacterial resistance.

OBJECTIVE:Extraintestinal pathogenic Escherichia coli (ExPEC) is a leading cause of community-acquired bacteremia and sepsis, which contributes to the substantial burden of invasive E. coli disease (IED) in older adults. This study aimed to estimate the O-serotype distribution of blood and sterile site ExPEC among older adults in China and the characteristics of antimicrobial resistance, O-serotypes, and O genotypes. METHODS:A total of 499 non-duplicated clinical isolates of E. coli derived from sterile body fluids from subjects aged ≥ 60 years from 55 medical institutions participating in the CHINET from different regions of China from 2016 to 2022 were collected. Antimicrobial susceptibility testing and whole genome sequencing (WGS) were performed for all isolates. For isolates with an O genotype pertaining to ExPEC9V (a group of 9 O-serotypes with high prevalence among bloodstream infections globally), an agglutination assay was conducted for validation. RESULTS:In this study, 82.2 % and 10.7 % of ExPEC isolates were tested as multidrug-resistant (MDR) and carbapenem-resistant E. coli (CREC), respectively. WGS revealed diverse STs and phylogroups. The most prevalent O serotypes were O25 (14.2 %), O75(6.2 %), O1(5.6 %), O6(4.6 %), O15(3.8 %), O45(3.6 %), O101(3.4 %), O11(3.4 %), O153(3.4 %), O8(3.4 %), O2/O50(3.0 %), and O9/O9a(3.0 %). Among MDR isolates, O25 was the dominant O serotype. 40.1 % of isolates were identified as ExPEC9V. CONCLUSIONS:In conclusion, O25 is the most prevalent O serotype among ExPEC isolates. The ExPEC9V O-serotype prevalence is generally consistent across MDR and different sexes.

Carbapenem-resistant organisms pose a significant public health threat due to high mortality and limited treatment options. This study aimed to evaluate the in vitro antimicrobial activity of the novel β-lactamase inhibitor FL058 combined with meropenem against carbapenem-resistant Enterobacterales and Pseudomonas aeruginosa clinical isolates. The MICs of 85 clinical isolates, including KPC- or NDM-producing Enterobacterales and carbapenem-resistant/susceptible P. aeruginosa, were determined using broth microdilution. Additionally, bactericidal activity, effects of culture conditions, post-antibiotic effect, and post-β-lactamase inhibitory effect of meropenem-FL058 were evaluated. Ceftazidime-avibactam served as comparator. Meropenem-FL058 showed potent activity against KPC-producing Enterobacterales (100

The emergence of Klebsiella pneumoniae carbapenemase-2 (KPC-2) and New Delhi metallo-β-lactamase (NDM)-coproducing hypervirulent carbapenem-resistant Klebsiella pneumoniae (KPC-2-NDM-hv-CRKP) poses a certain threat to public health. Currently, only a few sporadic reports of such double-positive hv-CRKPs were available. In this study, we isolated two KPC-2-NDM-5-hv-CRKPs from elderly patients with serious underlying diseases and poor prognoses. We found both FK3122 and FK3127 were typical multidrug-resistant (MDR) isolates, exhibiting high-level resistance to both carbapenems and novel β-lactamase inhibitors ceftazidime/avibactam. Notably, FK3122 is even resistant to cefiderocol due to multiple blaNDM-5 elements. Besides the MDR phenotype, A549 human lung epithelial cells and Galleria mellonella infection model all indicated that FK3122 and FK3127 were highly pathogenic. According to the whole-genome sequencing analysis, we observed over 10 resistant elements, and the uncommon co-existence of blaKPC-2, blaNDM-5, and virulence plasmids in both two isolates. Both virulence plasmids identified in FK3122 and FK3127 shared a high identity with classical virulence plasmid pK2044, harboring specific hypervirulent factors: rmpA and iuc operon. We also found that the resistance and virulence plasmids in FK3127 could not only be transferred to Escherichia coli EC600 independently but also together as a co-transfer, which was additionally confirmed by the S1-pulsed-field gel electrophoresis plasmid profile. Moreover, polymorphic mobile genetic elements were found surrounding resistance genes, which may stimulate the mobilization of resistance genes and result in the duplication of these elements. Considering the combination of high pathogenicity, limited therapy options, and easy transmission of KPC-2-NDM-5-hv-CRKP, our study emphasizes the need for underscores the imperative for ongoing surveillance of these pathogens.IMPORTANCEHypervirulent Klebsiella pneumoniae drug resistance has increased gradually with the emergence of carbapenem-resistant hypervirulent K. pneumoniae (hv-CRKP). However, little information is available on the virulence characteristics of the New Delhi metallo-β-lactamase (NDM) and Klebsiella pneumoniae carbapenemase-2 (KPC-2) co-producing K. pneumoniae strains. In this study, we obtained two KPC-2-NDM-hv-CRKPs from elderly patients, each with distinct capsule types and sequence types: ST11-KL64 and ST15-KL24; these ST-type lineages are recognized as classical multidrug-resistant (MDR) K. pneumoniae. We found these KPC-2-NDM-hv-CRKPs were not only typical MDR isolates, including resistance to ceftazidime/avibactam and cefiderocol, but also displayed exceptionally high levels of pathogenicity. In addition, these high-risk factors can also be transferred to other isolates. Consequently, our study underscores the need for ongoing surveillance of these isolates due to their heightened pathogenicity, limited therapeutic options, and potential for easy transmission.

ABSTRACTCarbapenem-resistant Enterobacterales (CRE) are some of the most important pathogens causing infections, which can be challenging to treat. We identified four blaIMP-carrying CRE isolates and collected clinical data. The transferability and stability of the plasmid were verified by conjugation, successive passaging, and plasmid elimination assays. The IncC blaIMP-4-carrying pIMP4-ECL42 plasmid was successfully transferred into the recipient strain, and the high expression of traD may have facilitated the conjugation transfer of the plasmid. Interestingly, the plasmid showed strong stability in clinical isolates. Whole-genome sequencing was performed on all isolates. We assessed the sequence similarity of blaIMP -harboring plasmid from our institution and compared it to plasmids for which sequence data are publicly available. We found that four blaIMP-carrying CRE belonged to four different sequence types. The checkerboard technique and time-kill assays were used to investigate the best antimicrobial therapies for blaIMP-carrying CRE. The time-kill assay showed that the imipenem of 1× minimum inhibitory concentration (MIC) alone had the bactericidal or bacteriostatic effect against IMP-producing strains at 4–12 h in vitro. Moreover, the combination of tigecycline (0.5/1/2 × MIC) and imipenem (0.5/1 × MIC) showed a bactericidal effect against the blaIMP-26-carrying CRECL60 strain.IMPORTANCECarbapenem-resistant Enterobacterales (CRE) are an urgent public health threat, and infections caused by these microorganisms are often associated with high mortality and limited treatment options. This study aimed to determine the clinical features, molecular characteristics, and plasmid transmissible mechanisms of blaIMP carriage as well as to provide a potential treatment option. Here, we demonstrated that conjugated transfer of the IncC blaIMP-4-carrying plasmid promotes plasmid stability, so inhibition of conjugated transfer and enhanced plasmid loss may be potential ways to suppress the persistence of this plasmid. The imipenem alone or tigecycline-imipenem combination showed a good bactericidal effect against IMP-producing strains. In particular, our study revealed that imipenem alone or tigecycline-imipenem combination may be a potential therapeutic option for patients who are infected with IMP-producing strains. Our study supports further trials of appropriate antibiotics to determine optimal treatment and emphasizes the importance of continued monitoring of IMP-producing strains in the future.

ABSTRACT The increasing prevalence of hypervirulent (hv) and carbapenem-resistant (CR) Klebsiella pneumoniae (Kp) highlights the importance of timely and accurate differential diagnosis for epidemiological investigation and clinical management. A multiplex quantitative real-time PCR (qRT-PCR) assay for the simultaneous identification of hvKp and CR-Kp was developed and validated with excellent performance in sensitivity and specificity. Generally, the gltA gene for Kp, the iucA, rmpA and rmpA2 genes for hvKp, and the Klebsiella pneumoniae carbapenemases (KPC) gene for CR-Kp were included in the qRT-PCR assay. The detection limits for classic Kp (cKp), CR-cKp, hvKp, and CR-hvKp strains could all reach 50 genome equivalent copies and 20 CFUs per reaction with high accuracy (R 2 > 0.99) and reliability (CV values < 3%). Detection results from 84 Kp positive clinical samples showed 31 hvKp with 8 CR-hvKp and 53 cKp with 1 CR-cKp strains. The presence of virulence-associated factors for the identified hvKp and KPC genes for CR-Kp was confirmed by previously developed conventional PCR and antimicrobial susceptibility tests, respectively. Furthermore, the qRT-PCR identified hvKp strains showed mortality rates of ≥40% in the outbred murine infection model, while no death for the identified cKp strains. These results indicated that our multiplex qRT-PCR assay could accurately identify hvKp and CR-Kp strains, which will be of great use for the rapid and accurate diagnosis in a clinical setting and the surveillance of the circulating Kp. IMPORTANCE Globally, the increasing number of hypervirulent Klebsiella pneumoniae (hvKp) and carbapenem-resistant Kp (CR-Kp) infections poses a huge public health challenge with high morbidity and mortality. Worrisomely, due to the mobility of elements carrying virulence and drug-resistance genes, the increasing prevalence of CR-hvKp has also been found with an overwhelming mortality rate in recent years. However, the current detection methods for hvKp and CR-Kp have many disadvantages, such as long turnaround time, complex operation, low sensitivity, and specificity. Herein, a more sensitive, rapid, single-reaction, and multiplex quantitative real-time PCR was developed and validated to differentiate the circulating lineages of Kp with excellent performance in sensitivity and specificity, providing a useful tool for the differential diagnosis and the surveillance of the circulating Kp.

Multidrug-resistant Enterobacterales and P. aeruginosa strains have become a global public threat, with the emergence and prevalence of plasmid-mediated extended-spectrum β-lactamases (ESBLs), AmpC cephalosporinases, and carbapenemases disseminated worldwide. Ceftazidime-avibactam, which is commercially available, has shown excellent in vitro activity against multidrug-resistant and carbapenem-resistant Enterobacterales and P. aeruginosa isolates.

Purpose Ceftazidime-avibactam (C-A) is a treatment option for carbapenem-resistant gram-negative bacterial (CR-GNB) infections, but little is known regarding its suitability for the intensive care unit (ICU). The current study aimed to analyze use of C-A for critically ill patients, determine independent predictors of clinical outcome and mortality and explore routine dosages for patients in continuous renal replacement therapy (CRRT).Patients and Methods A single-center, retrospective and observational study was conducted in critically ill patients receiving different C-A-based therapies for CR-GNB infections in a tertiary teaching hospital in Beijing, China. Demographic data, severity of infection, clinical outcomes and mortality were assessed. The primary and secondary outcome of this study was 90-day all-cause mortality and 14-day clinical response, respectively.Results A total of 43 patients with CR-GNB infection were enrolled, including 14 (32.6%) patients received C-A monotherapy. C-A monotherapy and combination with other agents did not affect 14-day clinical response or 90-day survival. All-cause mortality at 90-days was 39.5% (17/43). Multivariate Cox analysis showed that concomitant with bloodstream infection was independent risk factors for 90-day mortality and that the time to initiation of C-A and Acute Physiology and Chronic Health Evaluation (APACHE) score was independent predictors of 14-day clinical response. Five CRRT patients who received high-dose C-A therapy (>3.75 g/d) had prolonged survival compared with 5 who received low-dose C-A (<3.75 g/d, p = 0.03).Conclusion C-A was an effective therapy for severe CR-GNB infections and clinical response correlated with the time of C-A initiation. A dosage >3.75g/d C-A was associated with prolonged survival of CRRT patients. Randomized controlled trials or multicenter studies are needed to confirm these findings.

BACKGROUND:Chryseobacterium indologenes (C. indologenes) has recently emerged as a cause of life-threatening nosocomial infections in humans. This study aims to investigate the clinical characteristics, homology, and antimicrobial patterns of C. indologenes clinical isolates at a teaching hospital in Shanghai, China. METHODS:A total of 135 consecutive non-replicate clinical C. indologenes isolates from January 2010 to December 2018 were collected at a tertiary care university hospital in Shanghai, China. Genetic relatedness of the isolates was performed by pulsed-field gel electrophoresis (PFGE). The antimicrobial susceptibility of these isolates was measured by the microdilution broth method. The prevalence of β-lactamase genes was investigated by polymerase chain reaction (PCR), while the quinolone resistance-determining regions (QRDRs) were sequenced. RESULTS:All 135 C. indologenes isolates were collected from hospitalized patients with an average age of 55 years. Most of these clinical isolates were derived from ascites (59.3%) or urine (23.7%) specimens. Eighty (80/135) of the strains were classified as clone D by PFGE. In vitro drug susceptibility tests showed that minocycline and trimethoprim-sulfamethoxazole had sound antibacterial effects. However, more than 86% of the tested strains were resistant to cephalosporins (ceftazidime, cefotaxime), β-lactamase/β-lactamase inhibitors (cefoperazone-sulbactam), and carbapenems (meropenem, imipenem). Metallo-β-lactamase bla IND and type A broad-spectrum β-lactamase genes bla CIA were present in 135 and 103 isolates, respectively. The clinical strains in our hospital mainly carried bla IND-2 (89.6%, 121/135). Compared with previous studies, these strains had a high rate of resistance to quinolones. The resistance rates to levofloxacin, ciprofloxacin, norfloxacin, gatifloxacin, and nemonoxacin were as high as 83.7-94.8%. The mutations at Ser83Val, Ser83Tyr, and Asp87Gly in the QRDRs of GyrA were significantly related to the resistance of C. indologenes to levofloxacin. All but one quinolone-resistant strain contained at least one significant mutation. CONCLUSIONS:This study showed a clonal dissemination of C. indologenes isolates in infections at a tertiary care university hospital in Shanghai, China. Minocycline and trimethoprim-sulfamethoxazole had favorable in vitro antibacterial effects. However, the high resistance rate to β-lactams and quinolones was due to carrying β-lactamase (bla IND, bla CIA), and mutations in the QRDRs of GyrA.

Introduction. Linezolid-resistant (LZR) Staphylococcus capitis has recently emerged in our hospital, and its potential resistance mechanisms are still not clear.Aim. This study aimed to investigate the epidemiology, clinical and genetic characteristics, resistance mechanisms and biofilm formation capacity of LZR S. capitis isolated from patients at Huashan Hospital, Shanghai, PR China between 2012 and 2018.Methodology. Strains were subjected to antimicrobial susceptibility testing (AST) with antibiotics using the broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The presence of cfr, optrA and poxtA, as well as mutations in the 23S ribosomal (r)RNA and ribosomal proteins, was investigated using PCR and sequencing techniques. The genetic relationship between isolates was analysed using pulsed-field gel electrophoresis (PFGE) and whole-genome sequencing (WGS). Biofilm biomasses were detected by using crystal violet staining.Results. Twenty-one LZR S. capitis strains displayed MICs of 32-512 μg ml-1. All LZR strains showed G2576T and C2104T mutations in the 23S rRNA V region. Besides G2576T and C2104T, no base mutations were detected in the V region. The cfr was detected in 12 strains, while optrA and poxtA were not amplified in 21 S. capitis strains. PFGE showed that the LZR S. capitis strains belonged to a single clone. The phylogenetic tree showed that 20 LZR S. capitis strains were highly similar to LNZR-1, isolated from Harbin (located in the north of China) in 2013, which showed resistance to linezolid.Conclusions. In this research, cfr-negative strains displayed linezolid MICs of 32 μg ml-1. In comparison, cfr-positive strains exhibited linezolid MICs of 128-512 μg ml-1, indicating that high levels of linezolid resistance appear to be related to the presence of cfr. The outbreak of LZR S. capitis in our hospital needs to be monitored closely.

目的 监测2019年CHINET细菌耐药监测网二级医院临床分离菌株对抗菌药物的耐药性.方法 对13所二级医院临床分离菌采用纸片扩散法或自动化仪器法按CHINET统一监测方案进行抗菌药物敏感性试验.按2019年CLSI文件标准判断结果.结果 收集2019年1-12月上述医院临床分离菌共20739株,其中革兰阳性菌占24.5％,革兰阴性菌占75.5％.金黄色葡萄球菌和凝固酶阴性葡萄球菌中甲氧西林耐药株(MRSA和MRCNS)的平均检出率分别为34.3％和73.8％.甲氧西林耐药株对大多数测试药物的耐药率均显著高于甲氧西林敏感株(MSSA和MSCNS),未发现万古霉素耐药株.肠球菌属中粪肠球菌对多数测试抗菌药物的耐药率均显著低于屎肠球菌,两者中均无万古霉素耐药株.流感嗜血杆菌、肺炎链球菌和卡他莫拉菌等社区获得性肺炎常见的临床分离菌占比约为15.4％.其中,流感嗜血杆菌对氨苄西林的耐药率约为60％,卡他莫拉菌对阿莫西林-克拉维酸的耐药率低于5％.肺炎链球菌非脑脊液分离株中儿童分离株占71.7％,对青霉素的药敏试验显示青霉素敏感、中介、耐药肺炎链球菌分别为96.6％ 、2.9％和0.5％.肠杆菌科细菌对碳青霉烯类抗生素仍高度敏感,多数菌属耐药率均低于5％,其中克雷伯菌属对亚胺培南和美罗培南的耐药率分别为3.8％和3.9％.不动杆菌属细菌对亚胺培南和美罗培南的耐药率分别为47.5％和43.9％,铜绿假单胞菌对上述两药的耐药率分别为18.4％和13.7％.结论 二级医院在菌种分布和来源等特点及细菌耐药性均显著有别于三级医院;社区获得性肺炎临床分离菌的检出率较三级医院高,虽然临床常见细菌的耐药率和耐药菌株(MRSA,碳青霉烯类耐药的肺炎克雷伯菌、铜绿假单胞菌、鲍曼不动杆菌等)的检出率较三级医院低,但二级医院同样面临细菌耐药性的严重威胁,应引起足够重视;合理管控和规范治疗是当务之急.

目的 了解2019年复旦大学附属华山医院临床分离菌的分布及其对抗菌药物的敏感性.方法 采用自动化仪器或纸片扩散法按照统一方案进行抗菌药物敏感性试验,结果参考美国临床和实验室标准化协会(CLSI) 2019年文件标准判读.结果 共分离5 176株非重复临床分离菌,其中革兰阳性菌1 464株,占28.3％,革兰阴性菌3 712株,占71.7％.甲氧西林耐药金黄色葡萄球菌(MRSA)和甲氧西林耐药凝固酶阴性葡萄球菌(MRCNS)在各自菌种中的检出率分别为50.1％和77.5％.肠球菌属中粪肠球菌对测试抗菌药物的耐药率均明显低于屎肠球菌.葡萄球菌属、肠球菌属和链球菌属中均未发现万古霉素和利奈唑胺耐药株.肠杆菌科中,除克雷伯菌属和沙雷菌属对亚胺培南和美罗培南耐药率较高外,其他菌属均对这两种碳青霉烯类药物高度敏感,耐药率低于16％.碳青霉烯类耐药肠杆菌科细菌(CRE)总检出率为20.4％.肺炎克雷伯菌中碳青霉烯类耐药菌株的检出率为42.9％.铜绿假单胞菌对亚胺培南和美罗培南的耐药率分别为41.9％和32.2％,不动杆菌属对上述两药物的耐药率分别为67.5％和68.1％.结论 临床耐药菌株呈增长趋势,尤其是MRSA和CRE,应加强医院感染防控宣传,积极采取措施遏制耐药细菌的传播.

Purpose The OptrA protein is a member of ATP-binding cassette (ABC) transporters, a transporter family which can confer resistance to oxazolidinone antibiotics by transferring plasmid. We aim to describe the distribution of optrA-harbored Enterococcus in Huashan hospital in 2017 and to address the effects of optrA mutations on the susceptibility of linezolid antibiotic drug. Methods Linezolid-resistance-related genes were tested for Enterococcus by polymerase chain reaction (PCR) and then sequenced for amino acid substitution site analysis. Broth microdilution and agar dilution test were applied to determine the minimal inhibitory concentration (MIC) of linezolid for Enterococcus containing optrA. Pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) were used to evaluate the genotypes of optrA-positive isolates. To verify the functions of two main optrA variants, optrA over-expressing strains were constructed. Results Among 20 optrA-positive strains, only two were resistant to linezolid. No amino acid substitution existed in 23S rRNA V domain among Enterococcus faecalis. None had cfr, cfr(B) or cfr(C) genes. F101L and G4D/K/R or T150A were the main substitutions of ribosomal protein L4, L3, respectively. We found one Enterococcus faecium isolate co-contained optrA and poxtA and another E. faecalis isolate co-contained optrA and cfr(D), but they were not resistant to linezolid. Among 20 optrA-positive strains, ST-16 was the main type. Two main optrA variants KD (T112K, Y176D) and RDK (I104R, Y176D, E256K) slightly raised enterococci’s MIC of linezolid. Conclusion OptrA exists in linezolid non-resistant enterococci with diverse amino acid substitutions. The variants play different roles in changing the MIC of linezolid.