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