Changing distribution and antimicrobial resistance profiles of clinical isolates from wound pus:results from the CHINET Antimicrobial Resistance Surveillance Program,2015-2021
Objective To investigate the distribution and antimicrobial resistance profiles of the clinical isolates from wound pus in the CHINET Antimicrobial Resistance Surveillance Program from 2015 to 2021.Methods All the bacterial strains were isolated from wound pus samples from 2015 to 2021.The isolates were identified according to conventional methods.Antimicrobial susceptibility test was conducted by disk diffusion method or commercial automated susceptibility testing systems according to CHINET-specified uniform protocol.The results are interpreted according to the Clinical and Laboratory Standards Institute (CLSI) breakpoints (2021 Edition).Results A total of 90856 bacterial strains were isolated from wound pus samples from 2015 to 2021,of which gram positive bacteria accounted for 36.0% (32729/90856) and gram negative bacteria accounted for 64.0% (58127/90856).The most common bacterial species were Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa,and Enterococcus.About 88.9% of these strains were isolated from inpatients and 11.1% from outpatients.The strains collected from surgery department and internal medicine accounted for (53.4±3.6)% (49191/90856) and (9.6±1.0)% (8960/90856) on average over the 7-year period.E.coli showed low level resistance to carbapenems (1.1%).The prevalence of ESBLs-producing E.coli was 51.1%.More than 35% of the E.coli isolates were resistant to cefotaxime,ciprofloxacin,and trimethoprim-sulfamethoxazole.The prevalence of ESBLs-producing K.pneumoniae was 29.7%.The prevalence of imipenem-resistant and meropenem-resistant K.pneumoniae varied from 2015 to 2021,but reached the peak level (12.5% and 12.7%) in 2020.However,other Enterobacterales species showed low resistance rates to carbapenems.The prevalence of ESBLs-producing Klebsiella oxytoca and Proteus was 18.3% and 32.5%,respectively.About 13.1% and 10.6% of P.aeruginosa isolates were resistant to imipenem and meropenem,respectively.However,71.1% and 72.4% of A.baumannii isolates were resistant to imipenem and meropenem,respectively.The overall prevalence of MRSA was 22.7% in wound pus samples over the 7-year period.Three vancomycin-resistant strains and 122 linezolid-resistant isolates were identified in Enterococcus faecalis.Thirty-one vancomycin-resistant strains and 11 linezolid-resistant strains were detected in Enterococcus faecium.Conclusions The overall prevalence of MRSA,vancomycin-resistant Enterococcus (VRE),linezolid-resistant Enterococcus (LRE),ESBLs-producing Enterobacterales,and carbapenem-resistant organisms (CRO) in the isolates from wound pus samples was relatively lower than the corresponding prevalence in the total clinical isolates collected in the CHINET program.This finding suggests that the antimicrobial resistance profile of bacterial isolates may vary with the source of clinical samples.Therefore,we should strengthen the antimicrobial resistance surveillance for the isolates from different sites of infection.