Gene Expression of biofilm formation genes (plcN, bap) of Acinetobacter baumannii from wounds and burns patients in Baghdad, Iraq

Abstract

Acinetobacter baumannii has a high propensity to form biofilm and frequently causes medical device-related infections with multiple-drug-resistance in hospitals. The aim of this work is to study antimicrobial resistance and the role of plcN, bap genes in biofilm formation by A. baumannii to understand how this pathogen persists in the hospital environment and determine the minimum inhibition concentration (MIC) of IMIPENEM and CHALCONE. As well as comparing the effect before and after of using the antibiotic and chalcone. Two hundred and fifty (250) 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 2021) to (March 2022). Antibiotic resistance profile of isolates of A. baumannii was evaluated by VITEK-2 system and in vitro biofilm-forming ability was evaluated by micro titer plate methods, respectively. Isolates were tested for the presence of plcN, Bap genes Forty (40) A. baumannii isolates were identified by microscopic examination and biochemical tests. The identification of (40) isolates was verified using the VITEK-2 system and a molecular approach based on the rplB gene, which is an essential gene found in this genus. Antibiotic susceptibility testing was performed on all (40) identified isolates, and the findings revealed that 36 isolates had Multi-Drug Resistance (MDR). This study found that 16 isolates from these 16 isolates carrying the rblB gene and 6 isolates from 6 carrying plcN that confirmed by molecular detection methods, and 38 isolates from these 40 isolates had the ability to form biofilm in the micro titer plate method, and this study show there is down expression of plcN and bap with the antibiotic while overexpression of this genes with chalcone. In conclusion, there was strong association between presence of plcN, bap genes and biofilm formation by A. baumannii isolates. In addition, multidrug resistant isolates produced stronger biofilm than other isolates. These results indicate importance of biofilm in resistance of isolates and effect of the presence of plcN ,bap genes in biofilm formation by A. baumannii strains. and exposed to imipenem and chalcone decreased their biofilm gene expression level(plcN.bap).