Antibiotic resistance and virulence profiles of Proteus mirabilis isolated from broiler chickens at abattoir in South Africa

Abstract

Background: Proteus mirabilis has been identified as an important zoonotic pathogen, causing several illnesses such as diarrhoea, keratitis and urinary tract infections.

Objective: This study assessed the prevalence of P. mirabilis in broiler chickens, its antibiotic resistance (AR) patterns, ESBL-producing P. mirabilis and the presence of virulence genes.

Methods: A total of 26 isolates were confirmed as P. mirabilis from 480 pooled broiler chicken faecal samples by polymerase chain reaction (PCR). The disk diffusion method was used to evaluate the antibacterial susceptibility test, while nine virulence genes and 26 AR genes were also screened by PCR.

Results: All 26 P. mirabilis isolates harboured the ire A (siderophore receptors), ptA, andzapA (proteases), ucaA, pmfA, atfA, and mrpA (fimbriae), hlyA and hpmA (haemolysins)virulence genes. The P. mirabilis isolates were resistant to ciprofloxacin (62%) and lev-ofloxacin (54%), while 8 (30.7%) of the isolates were classified as multidrug resistant (MDR). PCR analysis identified the blaCTX-M gene (62%), blaTEM (58%) and blaCTX-M-2(38%). Further screening for AMR genes identified mcr-1, cat1, cat2, qnrA, qnrDand mecA, 12%, 19%, 12%, 54%, 27% and 8%, respectively for P. mirabilis isolates. The prevalence of the integron integrase intI1 and intI2 genes was 43% and 4%, respectively.

Conclusions: The rise of ciprofloxacin and levofloxacin resistance, as well as MDRstrains, is a public health threat that points to a challenge in the treatment of infections caused by these zoonotic bacteria. Furthermore, because ESBL-producing P. mirabilishas the potential to spread to humans, the presence of blaCTX-M -producing P. mirabilisin broilers should be kept under control. This is the first study undertaken to isolate P.mirabilis from chicken faecal samples and investigate its antibiotic resistance status as well as virulence profiles in South Africa.