Emergence of Resistance to Quinolones and β-Lactam Antibiotics in Enteroaggregative and Enterotoxigenic Escherichia coli Causing Traveler's Diarrhea

Elisabet Guiral; Milene Gonçalves Quiles; Laura Muñoz; Javier Moreno-Morales; Izaskun Alejo-Cancho; Pilar Salvador; Miriam J Alvarez-Martinez; Francesc Marco; Jordi Vila

doi:10.1128/AAC.01745-18

Emergence of Resistance to Quinolones and β-Lactam Antibiotics in Enteroaggregative and Enterotoxigenic Escherichia coli Causing Traveler's Diarrhea

Antimicrob Agents Chemother. 2019 Jan 29;63(2):e01745-18. doi: 10.1128/AAC.01745-18. Print 2019 Feb.

Authors

Affiliations

¹ Institute of Global Health of Barcelona, Barcelona, Spain.
² Department of Clinical Microbiology, Hospital Clinic, School of Medicine, University of Barcelona, Barcelona, Spain.
³ Institute of Global Health of Barcelona, Barcelona, Spain jvila@clinic.cat.

^# Contributed equally.

Abstract

The objective of this study was to assess the antimicrobial resistance of enteroaggregative Escherichia coli (EAEC) and enterotoxigenic E. coli (ETEC) strains causing traveler's diarrhea (TD) and to investigate the molecular characterization of antimicrobial resistance genes to third-generation cephalosporins, cephamycins, and quinolones. Overall, 39 EAEC and 43 ETEC clinical isolates were studied. The susceptibilities of EAEC and ETEC against ampicillin, amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, tetracycline, co-trimoxazole, nalidixic acid, ciprofloxacin, azithromycin, and rifaximin were determined. All genes encoding resistance determinants were detected by PCR or PCR plus DNA sequencing. The epidemiology of selected EAEC and ETEC strains was studied using multilocus sequence typing (MLST). The resistance to quinolones of EAEC and ETEC strains causing TD has significantly increased over the last decades, and high percentages have been found especially in patients traveling to India and sub-Saharan Africa. Sequence type 38 (ST38) and ST131, carrying the bla_CTX-M-15 and bla_CTX-M-27 genes, respectively, are highly prevalent among extended-spectrum β-lactamase (ESBL)-producing EAEC and ETEC strains. The cephamycinase ACT-20 is described in the present study for the first time in EAEC and ETEC strains causing TD in patients who had traveled to Central America. The percentages of resistance to azithromycin in EAEC and ETEC isolates from patients to Southeast Asia/India and Africa are above 25%. Meanwhile, rifaximin is still active against EAEC and ETEC, with the prevalence of resistant strains not being high. In conclusion, fluoroquinolones should no longer be considered the drugs of choice for the prevention or treatment in TD for travelers traveling to India and Africa. Azithromycin and rifaximin are still a good alternative to treat TD caused by EAEC or ETEC.

Keywords: cephalosporin; enteroaggregative E. coli; enterotoxigenic E. coli; quinolones; resistance; traveler’s diarrhea.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents / therapeutic use*
Drug Resistance, Multiple, Bacterial / physiology*
Enterotoxigenic Escherichia coli / drug effects*
Escherichia coli Infections / drug therapy*
Escherichia coli Infections / microbiology
Gastrointestinal Diseases / drug therapy
Gastrointestinal Diseases / microbiology
Humans
Microbial Sensitivity Tests
Multilocus Sequence Typing
Quinolones / therapeutic use*
beta-Lactam Resistance / physiology
beta-Lactams / therapeutic use*

Substances

Anti-Bacterial Agents
Quinolones
beta-Lactams