Effects of Meropenem at Sub-inhibitory Doses on the Expression of Biofilm-associated Protein by Acinetobacter baumannii

Abstract

Objective(s): Acinetobacter baumannii has a high proclivity for forming biofilm and is a common source of multidrug-resistant (MDR) infections caused by medical devices in hospitals. This research aims to see how sub-inhibitory meropenem doses affect the expression of biofilm-associated proteins. Methods: Two hundred and fifty samples were collected from various sites in Baghdad, Iraq hospitals and divided into two groups based on their source: clinical 150 and environmental (100) samples, collected from October 2020 to March 2021. Five bacterial isolates were examined for the presence of the bap gene, were treated with sub-inhibitory concentrations of meropenem to evaluate gene expression level. Results: Eighty-three A. baumannii isolates were identified by microscopic examination and biochemical tests. The identification of 83 isolates was verified using a molecular approach based on the rplB gene, an essential gene found in this genus. Antibiotic susceptibility testing was performed on all 83 identified isolates, and the findings revealed that 36 isolates had MDR. This study found that 30 isolates from these 36 isolates carrying the Bap gene that confirmed by molecular detection methods, meropenem dose (0.0005 mg/mL) were with very low inhibition activity against the bacterial strains for that they were considered as sub-inhibitory concentrations, Bap gene expression showed an almost apparent decrease in all isolates in antibiotic treatment. Conclusion: There was a clear link between the presence of the bap gene and the prevalence of multidrug-resistant isolates. These findings point to the importance of isolate resistance and the role of the bap gene in biofilm formation by A. baumannii strains. Furthermore, these findings point to the necessity for more research. This study demonstrated the role of rplB gene for molecular detection A. baumannii at the level of genus and species, respectively. Meropenem at sub-inhibitory concentration has decreased Bap gene expression level.