The Effect of Lactobacillus Casei-Free Floating Fraction on the Expression of Class I Integron Gene in Clinical Isolates of Acinetobacter Baumannii by Real Time PCR

The most common way for the spread of resistance genes and the emergence of multidrug resistance (MDR)-Acinetobacter baumannii species is the presence of genetic elements called integrons. Therefore, in recent years, the use of probiotics has been recommended to reduce the complications of resistant bacteria and treatment failure. Therefore, the aim of this study was to investigate the effect of probiotic Lactobacillus casei supernatant on the expression of class 1 integron gene in A. baumannii isolates by Real time PCR.

Sixty clinical samples of blood, respiratory secretions, urine, and ulcers were collected from hospitals in Saveh, Iran. The presence of the intI gene was evaluated by PCR. After treatment with the sub-MIC strains of L. casei supernatant, mRNA was extracted and Real-time PCR was performed to determine the level of integron gene expression and finally the expression level was determined using Δct method. Expression analysis was performed by relative mRNA expression compared to the standard strain and it was performed in SPSS version 18 using t-test statistical analysis.

Out of 12 isolates of A. baumannii, the prevalence of IntI gene was 100%. The fold change for the intI gene was -1.18, indicating that it decreased in the treated group compared to the untreated group (P <0.05).

The results showed that the probiotic supernatant was able to reduce the expression of the intI gene; therefore, the use of probiotics as a supplement or alternative therapy in the drug-resistance microbial infections is recommended.