Genotypic and Cartwheel Phenotypic Detection of AcrAB-TolC, AcrAD-TolC, and AcrEF-TolC Pumps in Proteus mirabilis

Abstract Background: Opportunistic pathogen Proteus mirabilis is resistant to multiple antibiotic classes and frequently causes infections. A significant threat to global public health exists in the emergence and spread of novel antimicrobial resistance genes. Sensitivity was recently found to be decreased by RND efflux pump (EP) genes. Using the Cartwheel Ethidium Bromide (EtBr) method, efflux pump activity in bacteria can be measured. Objective: The purpose of this study was to detect RND pumps (AcrAB-TolC, AcrAD-TolC, and AcrEF-TolC) genotypically and phenotypically among P. mirabilis isolated from urinary tract infections (UTI). Materials and Methods: Standard biochemical tests and PCR using the atpD gene as species-specific primers were used to confirm the diagnosis of suspected P. mirabilis isolates. The disc diffusion method was used to test antibiotic susceptibility. The cartwheel EtBr method was used to screen pump activity, whereas PCR was used to detect the RND genes. Results: Out of 515 urine specimens collected from patients with UTI, only 70 isolates were confirmed by PCR as P. mirabilis . Nearly all isolates were multidrug resistant (MDR) with Multiple antibiotic resistance (MAR) index values ranging from 0.15 to 0.6. The phenotypic detection of pump by EtBr cartwheel method revealed that the efflux activity was categorized as 64.3% positive, 24.3% intermediate, and 11.6% negative. The frequency of acrA, acrB, acrD, acrE, acrF , and tolC genes were 51.4%, 61.4%, 88.6%, 94.3%, 88.6%, and 51.4%, respectively. Conclusion: All MDR isolates of P. mirabilis harbor at least a single RND pump with valuable activity pushing an alarm and thinking about anti-efflux strategies for treatment future.