Abstract:
The aim of this study was to determine the resistance phenotypes of selected enteric bacteria isolated from nonhuman
primates at a wildlife-human interface. Bacterial isolates from faecal samples of non-human primates at
two wildlife rehabilitation centres in South Africa were screened for the presence of Escherichia coli. The
biochemical characterisation of E. coli and E. coli-like bacteria revealed both adonitol positive and sorbitol
negative strains – a unique characteristic of Escherichia fergusonii and Escherichia coli K99. Further tests were
carried out to identify the isolates, namely growth on Simmons citrate agar supplemented with 2% adonitol and
biochemical tests based on their ability to ferment cellobiose and D-arabitol. Antimicrobial sensitivity was
determined with microbroth dilution tests employing microtitre plates with 21 different antimicrobial drugs.
Molecular characterisation was done with a duplex polymerase chain reaction (PCR) assay that targeted the yliE
and EFER_1569 genes. E. fergusonii strains were confirmed by the presence of a 233 bp segment of the yliE gene
and a 432 bp segment of the EFER_1569 gene.
Twenty-three E. coli-like bacteria were confirmed as E. fergusonii based on the confirmatory tests and they
were in 100% agreement. Approximately 87% of them were resistant to polymyxins B and E (colistin) as well as
the carbapenem group with occasional resistance to amikacin.
This is the first reported isolation and identification of E. fergusonii strains in non-human primates. The
findings point to E. fergusonii as a possible emerging pathogen of zoonotic importance.
