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

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 blaCTX-M-15 and blaCTX-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.

Genomic Surveillance of Ceftriaxone-Resistant Escherichia coli in Western New York Suggests the Extended-Spectrum β-Lactamase blaCTX-M-27 Is Emerging on Distinct Plasmids in ST38

“…In this study, ST131 exhibited increased frequency of resistance to fluoroquinolones and ampicillin-sulbactam compared to ST38, which was often non-susceptible to nitrofurantoin. Increased frequency of fluoroquinolone resistance in ST131 vs. ST38 has been previously described (Alghoribi et al, 2015;Gauthier et al, 2018;Guiral et al, 2019) and is a hallmark of clade C strains. Only 3/41 ST131 isolates in this study were susceptible (S or I) to fluoroquinolones, all of which were clade A.…”

“…However, hinting that the epidemiology may be changing, the 2016 SENTRY Antimicrobial Surveillance Study demonstrated that the bla CTX-M-27 gene (17.3%) is also significant in E. coli UTI and BSI isolates, compared to the bla CTX-M-15 gene (55.5%; Mendes et al, 2019). Similarly, ST131 carrying the bla CTX-M-27 gene is also a frequent minority around the globe (Livermore et al, 2007;Cao et al, 2011;Dahbi et al, 2013;Matsumura et al, 2013;Seiffert et al, 2013;Roer et al, 2017;Guiral et al, 2019;Peirano and Pitout, 2019;Birgy et al, 2020). The relative advantages of one CTX-M family gene vs. another are not clear, though the bla CTX-M-27 gene may confer additional activity against ceftazidime (Bonnet et al, 2003).…”

Molecular diversity of Extended‐spectrum β‐lactamase‐producing Escherichia coli from vultures in Canary Islands

“…coli commonly associated with urinary tract infections and bacteremia in humans (Hernandez et al ., 2013; Dolejska and Literak, 2019; Shnaiderman‐Torban et al ., 2020) but also found in wildlife (Alcala et al ., 2016; Guenther et al ., 2017). According to a recent study, the ST38/CTX‐M‐15‐resistant clone was found in a Mongolian wild bird (Guenther et al ., 2017) and the same combination was detected in a human clinical isolate in India (Guiral et al ., 2019). These results are in line with the fact that ST38 lineage is considered an expanded and pandemic clone as well as this lineage appears to be independent of antimicrobial selective pressure in clinical environments (Guenther et al ., 2017).…”

F Plasmids Are the Major Carriers of Antibiotic Resistance Genes in Human-Associated Commensal Escherichia coli

“…The most well-known member of this family, Escherichia coli , is ubiquitous as an intestinal commensal in humans, but it can act as a diarrheagenic gastrointestinal tract pathogen ( 1 ) or as an extraintestinal pathogen causing urinary tract infections ( 2 ) and sepsis ( 3 ). Common E. coli lineages causing either intestinal or extraintestinal disease are increasingly found to be resistant to multiple drugs ( 4 – 6 ). Antibiotic resistance in E. coli can arise by mutations in diverse targets or by acquisition of preexisting genes whose products target antibiotics for alteration or efflux ( 7 , 8 ).…”