Population Diversity of Antibiotic Resistant Enterobacterales in Samples From Wildlife Origin in Senegal: Identification of a Multidrug Resistance Transposon Carrying blaCTX-M-15 in Escherichia coli

IntroductionThe role of wildlife in the transmission of antimicrobial resistant (AMR) is suspected but scarcely reported in current studies. Therefore, we studied the dynamics and prevalence of antibiotic-resistant Enterobacterales in antibiotic-limited areas of Senegal. Materials and MethodsWe collected fecal samples from monkeys and apes (N = 226) and non-fecal environmental samples (N = 113) from Senegal in 2015 and 2019. We grew the samples on selective media, subsequently isolated AMR Enterobacterales, and then sequenced their genomes. ResultsWe isolated 72 different Enterobacterales among which we obtained a resistance rate of 65% for colistin (N = 47/72) and 29% for third generation-cephalosporin (C3G) (29%, N = 21/72). Interestingly, almost 46% of our isolates, among Enterobacter sp., Citrobacter cronae and Klebsiella aerogenes, belong to 34 new STs. Moreover, the genes bla(CTX-M-15), bla(TEM1B), sul2, dfrA14, qnrs, aph(3 ''), aph(6), tetA, and tetR harbored within a transposon on the IncY plasmid of ST224 Escherichia coli were transferred and inserted into a ST10 E. coli phage coding region. ConclusionWildlife constitutes a rich, unexplored reservoir of natural microbial diversity, AMR genes and international resistant clones pathogenic in humans. The presence of a transposon that carries AMR genes is intriguing since no antibiotics are used in the non-human primates we studied.

Automated summary

The study reveals a high prevalence of antibiotic-resistant Enterobacterales in wildlife in antibiotic-limited areas of Senegal. These resistant bacteria not only show high resistance rates to multiple antibiotics, but also carry novel resistance genes.