Abstract
ObjectiveThe objective of the study was to investigate the antimicrobial susceptibility and extended-spectrum beta-lactamase (ESBL) positive rates of Escherichia coli from community-acquired urinary tract infections (CA-UTIs) in Chinese hospitals.Materials and MethodsA total of 809 E. coli isolates from CA-UTIs in 10 hospitals (5 tertiary and 5 secondary hospitals) from different regions in China were collected during the period 2016–2017 according to the strict inclusion criteria. Antimicrobial susceptibility testing was carried out by standard broth microdilution method. Isolates were categorized as ESBL-positive, ESBL-negative, and ESBL-uncertain groups according to the CLSI recommended phenotypic screening method. ESBL and AmpC genes were amplified and sequenced on ESBL-positive and ESBL-uncertain isolates.ResultsThe antimicrobial agents with susceptibility rates of greater than 95% included imipenem (99.9%), colistin (99.6%), ertapenem (98.9%), amikacin (98.3%), cefmetazole (97.9%), nitrofurantoin (96%), and fosfomycin (95.4%). However, susceptibilities to cephalosporins (varying from 58.6% to 74.9%) and levofloxacin (48.8%) were relatively low. In the phenotypic detection of ESBLs, ESBL-positive isolates made up 38.07% of E. coli strains isolated from CA-UTIs, while 2.97% were ESBL-uncertain. Antimicrobial susceptibilities of imipenem, cefmetazole, colistin, ertapenem, amikacin, and nitrofurantoin against ESBL-producing E. coli strains were greater than 90%. The percentage of ESBL-producing strains was higher in male (53.6%) than in female patients (35.2%) (p < 0.001). CTX-M-14 (31.8%) was the major CTX-M variant in the ESBL-producing E. coli, followed by CTX-M-55 (23.4%), CTX-M-15 (17.5%), and CTX-M-27 (13.3%). The prevalence of carbapenem-resistant E. coli among CA-UTI isolates was 0.25% (2/809).ConclusionOur study indicated high prevalence of ESBL in E. coli strains from strictly defined community-acquired urinary tract infections in adults in China. Imipenem, colistin, ertapenem, amikacin, and nitrofurantoin were the most active antimicrobials against ESBL-positive E. coli isolates. blaCTX–M–14 is the predominant esbl gene in ESBL-producing and ESBL-uncertain strains. Our study indicated that the use of cephalosporins and fluoroquinolone needs to be restricted for empirical treatment of CA-UTIs in China.
Highlights
Escherichia coli (E. coli) is a common pathogen of communityacquired infections such as intra-abdominal infection, urinary tract infection (UTI), and pelvic inflammatory disease
During the period 2016–2017, a total of 809 E. coli isolates from community-acquired adult urinary tract infections (CA-UTIs) were consecutively collected from 10 hospitals located in the following regions of China: northeastern (121 isolates), northern (179 isolates), central (172 isolates), western (159 isolates), and eastern (178 isolates)
Inclusion Criteria (1) All E. coli isolates were cultured from urines of adult UTI patients (>18 years old) from outpatient clinic/emergency department or admitted to a hospital in less than 48 h. (2) Isolates were cultured from uncomplicated UTI, such as acute cystitis, acute pyelonephritis, with evidence support of clinical symptoms, urine routine test, and/or imaging examination
Summary
Escherichia coli (E. coli) is a common pathogen of communityacquired infections such as intra-abdominal infection, urinary tract infection (UTI), and pelvic inflammatory disease. Increasing trend in extended-spectrum beta-lactamase (ESBL) rates was seen among isolates from CA-UTIs in many regions; the antimicrobial resistance surveillance program in China showed that the proportion of ESBL-producing E. coli in community-acquired infections ranges from 45.2 to 68.2% (Yun et al, 2014; Fupin et al, 2017), in Canada, from 9.1 to 14.1%, and in the United States, from 6.5% in 2010 to 16.0% in 2014 (Lob et al, 2016). The inclusion and exclusion criteria of isolates is an important factor, which may over- or underestimate the ESBL rates or antimicrobial resistance in community-acquired infections. Studying the antimicrobial resistance patterns of E. coli in real community-acquired infections is important for understanding the resistance status and for choosing the most appropriate empirical antimicrobial therapy for CAUTIs (Lob et al, 2015). The real ESBL rate and molecular epidemiology in CA-UTIs in China is unclear
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