Molecular Characterization and Antimicrobial Susceptibility Patterns of Escherichia coli in Captive and Wild Olive Baboon (Papio anubis) Gut

Abstract

Escherichia coli are normal microflora in the gut of warm-blooded animals but some strains are pathogenic to humans causing fatal diarrhea. Cases of antimicrobial resistance have been reported on E. coli isolated from different domestic and wild animals indicating that they are potential reservoirs for zoonotic transmission of both pathogenic and resistant strains of bacteria. Zoonotic transmission is favoured by anthropogenic activities. This study was aimed at undertaking comparative characterization of E. coli pathotypes that colonize the gut of captive and wild olive baboons (Papio anubis) as well as determining antimicrobial susceptibility profiles and presence of extended spectrum β-lactamase genes in all E. coli isolates. Stool samples were collected from a total of 124 olive baboons divided into two equal groups of captive and wild. All E. coli were isolated by culture based technique and characterized using polymerase chain reaction to determine of virulence genes associated with each pathotype. All E. coli isolates were subjected to susceptibility testing to fourteen antimicrobial agents followed by characterization of three putative resistance genes; blaCTX-M, blaTEM and blaSHV. Enteropathogenic, enterotoxigenic, enteroinvasive and enterohaemorrhagic E. coli were detected from both captive and wild baboons. However, enteropathogenic, enterotoxigenic and enteroinvasive isolates were detected in 29.0% of wild baboons whereas carriage of enterotoxigenic, enteropathogenic, enteroinvasive and enterohaemorrhagic isolates occurred in 24.2% of captive population (p<0.05). Wild olive baboons appeared to harbor more enteropathogenic E. coli (22.6%) compared to the captive population (4.8%). On the other hand, prevalence of enterotoxigenic E. coli was higher among the captive olive baboons (14.5%) compared to the wild population (1.6%). E. coli isolates from both groups of animals were resistant to all antimicrobial agents except ciprofloxacin. Prevalence of ampicillin resistance was high in E. coli isolated from both wild (35.5%) and captive (32.3%) baboons. There was higher prevalence of Extended Spectrum β-Lactamases in E. coli isolated from wild (17.7%) than captive (14.5%) baboons (p<0.05). Carriage of blaSHV gene was higher among E. coli isolates from wild olive baboons (11.3%) compared to the captive population (1.6%). There was higher prevalence of blaCTX-M (8.1%) and blaTEM (4.8%) in captive olive baboons compared to the wild population (3.2%) although these differences were not significant (p>0.05). This study demonstrates that the gut of both captive and wild populations of olive baboons is colonized by E. coli that are not only pathogenic to humans but also harbor extended-spectrum β-lactamases that are highly transmissible. As reservoirs of E. coli pathotypes and extended spectrum β-lactamases producers, baboons could play a potential role not only in transmission of diarrheal diseases, but also of antibiotic resistance genes to the environment and other animals including humans. There is need for further investigations to characterize additional antimicrobial resistance genes and their variants. Regular training of laboratory animal care staff on prevention and control of zoonotic transmission of diarrheagenic E. coli is required.