Dominance of ST131, B2, blaCTX-M-15, and papA-papC-kpsMII-uitA among ESBL Escherichia coli isolated from bloodstream infections in Quito, Ecuador: a 10-year surveillance study (2009-2019)

Aims: This study aimed to examine antibiotic resistance and the epidemiology of extended-spectrum beta-lactamases (ESBL)-producing Escherichia coli associated with bloodstream infections over a period of 10 years.Methods and results: Isolates were collected from January 2009 to December 2019 and those testing for E. coli were included. Antibiotic susceptibility was tested using the VITEK (R) system. Selected isolates were further characterized by amplification of marker genes (virulence traits, phylogroups, and sequence types). A total of 166 ESBL-producing E. coli were recovered. The bla(CTX-M-15) allele was the most abundant. Most of the isolates were resistant to ceftriaxone, cefepime, ceftazidime, ampicillin/sulbactam, piperacillin/tazobactam, and ciprofloxacin. No resistance to carbapenems was registered. More than 80% of bacteria were classified as extraintestinal pathogenic E. coli (ExPEC), and the combination of virulence traits:papA-papC-kpsMII-uitA was the most common. Phylogroup B2 was the most prevalent, and bacteria predominantly belonged to ST131.Conclusions: There was an increase in the ExPEC ESBL-E coli in bloodstream infections and the relationship between the isolates found in these infections during these 10 years.

Automated summary

This study found an increase in ESBL-producing E. coli in bloodstream infections over the past 10 years, with a certain level of correlation between the isolates found during this period. The majority of these isolates were resistant to ceftriaxone, cefepime, ceftazidime, ampicillin/sulbactam, piperacillin/tazobactam, and ciprofloxacin, but not carbapenems. Over 80% of the isolates were classified as extraintestinal pathogenic E. coli, and the combination of virulence traits:papA-papC-kpsMII-uitA was the most common. Phylogroup B2 was the most prevalent, and the bacteria predominantly belonged to ST131.