Changes of antibiotic resistance over time among Escherichia coli peritonitis in Southern China

Escherichia coli (E. coli) is the main cause of Gram-negative bacterial peritonitis among peritoneal dialysis patients. According to the 2016 update of the International Society for Peritoneal Dialysis Peritonitis Recommendations, drug susceptibilities of specific organisms should be regularly monitored. The aim of this study was to examine the evolution of antimicrobial resistance of E. coli peritonitis from 2006 to 2018. Two hundred and fifty-three episodes of E. coli peritonitis were enrolled in our study, corresponding to a rate of 0.024 episodes per patient-year. According to drug sensitivity test results, isolates were most sensitive to carbapenems, followed by cefmetazole, piperacillin/tazobactam, cefotetan and amikacin, with an overall rate of more than 90% in both cohorts. Cefazolin and ciprofloxacin resistance increased significantly from 2006-2011 to 2012-2018. Conversely, cefepime and ceftazidime resistance decreased significantly. The extended-spectrum β-lactamase (ESBL) rate fluctuated from 34.7% in 2006-2011 to 46.8% in 2012-2018. Compared with the ESBL-negative strains, ESBL-producing E. coli were more likely be resistant to ampicillin, ampicillin/sulbactam, cephalosporins, quinolones, aminoglycosides, furadantin and sulfamethoxazole and accounted for over 50% of the drug resistance. In the correlation analysis, E. coli displayed significantly increased resistance to cefazolin and ciprofloxacin, a finding correlated with ESBL production (r = 0.883 and 0.276 respectively, p < 0.001 and p = 0.003). In conclusion, the rate of E. coli peritonitis declined stably in recent years, but the resistance to antimicrobial was high.