Highly diverse and antimicrobial susceptible Escherichia coli display a naïve bacterial population in fruit bats from the Republic of Congo

Abstract

Bats are suspected to be a reservoir of several bacterial and viral pathogens relevant to animal and human health, but studies on Escherichia coli in these animals are sparse. We investigated the presence of E. coli in tissue samples (liver, lung and intestines) collected from 50 fruit bats of five different species (Eidolon helvum, Epomops franqueti, Hypsignathus monstrosus, Myonycteris torquata, Rousettus aegyptiacus) of two different areas in the Republic of Congo between 2009 and 2010. To assess E. coli pathotypes and phylogenetic relationships, we determined the presence of 59 virulence associated genes and multilocus sequence types (STs). Isolates were further tested for their susceptibility to several antimicrobial substances by agar disk diffusion test and for the presence of an Extended-Spectrum Beta-Lactamase phenotype. E. coli was detected in 60% of the bats analysed. The diversity of E. coli strains was very high, with 37 different STs within 40 isolates. Occasionally, we detected sequence types (e.g. ST69, ST127, and ST131) and pathotypes (e.g. ExPEC, EPEC and atypical EPEC), which are known pathogens in human and/or animal infections. Although the majority of strains were assigned to phylogenetic group B2 (46.2%), which is linked with the ExPEC pathovar, occurrence of virulence-associated genes in these strains were unexpectedly low. Due to this, and as only few of the E. coli isolates showed intermediate resistance to certain antimicrobial substances, we assume a rather naïve E. coli population, lacking contact to humans or domestic animals. Future studies featuring in depth comparative whole genome sequence analyses will provide insights into the microevolution of this interesting strain collection.

Characterization of ESBL-Producing Enterobacteria from Fruit Bats in an Unprotected Area of Makokou, Gabon

“…Moreover, in our data, CTX-M-15 was found either as a single resistance determinant in E. coli (54.54%) and E. cloacae and K. pneumoniae (9.09%) or was associated with SHV-11 in K. pneumoniae (27.27%). The prevalence of ESBL-producing enterobacteria (37.93%) was higher than that obtained in E. coli sampled in bats and other wild animals in Nigeria [13,15] and the Republic of Congo [44], in which no phenotype of ESBL resistance was found. The CTX-M-15-producing K. pneumoniae was found in a gorilla in its natural habitat in the Dzanga Ndoki National Park [27].…”

“…The presence of antibiotic resistance linked to blaCTX-M-15 and blaSHV-11 genes is probably linked to antibiotics used by humans, since our phylogenetic analyses show that all the sequences obtained in bats that carry CTX-M-15 or SHV-11 clustered with one human bacterial strain from Turkey and Tunisia, respectively. This suggests that the prevalence of antibiotic resistance in wild animals depends on the antibiotics consumed by human populations at each site and the density of the human population in contact with fauna [44].…”

Impact of human-associated Escherichia coli clonal groups in Antarctic pinnipeds: presence of ST73, ST95, ST141 and ST131

“…The authors stated that known human isolates might be present in wild animals as part of the naïve E . coli population more frequently as originally assumed 39 .…”

High Prevalence of CTX-M-15-Type ESBL-Producing E. coli from Migratory Avian Species in Pakistan

“…Virulence gene analysis exhibited an overall low number of VAGs in wild birds studied. ExPEC were defined as suggested previously which is mainly based on the presence of at least two VAGs including P fimbrial genes papA and papC , S frimbriae genes sfa/foc , afimbrial adhesion genes afa/dra , group 2 polysaccharide capsule gene kpsMTII and iron acquisition gene iutA (Nowak et al, 2017 ). According to this definition, none of the isolates is regarded as ExPEC (Table 1 ).…”

“…We also found high frequency of astA and iha genes. These are only putative virulence genes and their exact involvement in the pathogenesis is not well understood, although they have been frequently reported in enteroaggregative E. coli and avian pathogenic E. coli (Nowak et al, 2017 ).…”