Evaluation of the Probiotic Effect of Lactobacillus Rhamnosus on blaCMY Beta- Lactamase Gene Expression in Clinical Isolates of Escherichia Coli

Escherichia coli, as a member of the Enterobacteriaceae family, belong to the group of facultative anaerobic gram-negative bacilli, and could be an important cause of hospital infections in intensive care units. Due to the widespread use of antibiotics, antibiotic resistance is one of the biggest causes of antibiotic treatment failure. Lactobacillus lactic acid bacteria (LAB) are one of the most important strains of probiotics, which have also been considered for their anti- cancer properties since the antimicrobial effects of some probiotics have been determined. This research aims to investigate the effect of Lactobacillus rhamnosus probiotic on blaCMY beta- lactamase gene expression in Escherichia coli clinical isolates.

In this experimental study, 60 Escherichia coli isolates were collected from hospitals in Mashhad and Neishabur and confirmed by microbiological and biochemical tests. The test to determine the drug sensitivity of the samples to antibiotics was done by the disc diffusion method. Then the resistant isolates were isolated and after re-cultivation, they were treated with probiotic extract. After that, their minimum growth inhibitory concentration (MIC) was compared to these antibiotics by conducting serial dilution method according to CLSI standards. Then, using real- time PCR, the expression of blaCMY gene in control and treatment samples was investigated and compared with each other. Statistical analysis was done with SPSS (independent t-test).

The findings showed that the gene expression in samples treated with Lactobacillus rhamnosus probiotic extract was significantly reduced compared to the control samples (P < 0.001). The mean and standard deviation of the treatment group and control group are 0.35 ± 0.1 and 0.1 ± 1 respectively.

Lactobacillus rhamnosus probiotic extract exerted bactericidal effects through its binding ability, competitive power, and the power to inhibit uropathogens.