Detection of β-Lactamase-Producing Proteus mirabilis Strains of Animal Origin in Andhra Pradesh, India and Their Genetic Diversity

Proteus mirabilis is abundant in soil and water. Although this bacterium is part of the normal human intestinal flora, it can cause serious infections in humans, including complicated urinary tract infections. This pathogen is also commonly associated with multidrug resistance. In the present study, analysis of 1,093 samples from foods of animal origin and animal intestinal samples recovered 232 P. mirabilis isolates identified by PCR assay. Of these 232 isolates, 72 produced beta-lactamase (determined by both phenotypic and genotypic methods), with the highest prevalence in poultry cloacal swabs (11.82%) followed by mutton (9.18%), khoa (6.32%), pork (5.63%), pig rectal swabs (5.52%), beef (5.45%), and chicken (5.13%) but none from sheep rectal swabs and bovine rectal swabs. Among beta-lactamase genes, bla(TEM) was the predominant gene detected (59 isolates) followed by bla(OXA) (11 isolates), bla(SHV) (5 isolates), bla(FOX) (5 isolates), bla(CIT) (4 isolates), bla(CTX-M1) and bla(CTX-M9) (2 isolates each) and bla(CTX-M2), bla(DHA), and bla(EBC) (1 isolate each). None of the isolates carried bla(ACC), bla(MOX), or carbapenemase genes (bla(VIM), bla(IMP), bla(KPC), and bla(NDM-1)). Dendrogram analysis of enterobacterial repetitive intergenic consensus sequences and repetitive extragenic palindromic sequences obtained with PCR analysis of beta-lactamase-producing isolates revealed 63 isolates, but 9 isolates did not yield bands. The analysis revealed that 6.58% of the samples had beta-lactamase-producing P. mirabilis isolates that may affect food safety and contaminate the environment. Further genotyping revealed the genetic relationships between isolates of different origin. These findings emphasize the need for careful use of antibiotics to control the spread of beta-lactamase-producing bacteria.