Detection of quorum sensing activity among biofilm forming Acinetobacter baumannii isolates

Bacteria communicate with each other by producing chemical signals (acyl homoserine lactones, AHLs) through the quorum sensing (QS) signaling circuits, which control the expression of virulence genes. Also QS plays a significant role in biofilm formation, therefore it is important to develop new strategies to inhibit QS and get rid of biofilm. Acinetobacter baumannii is a major nosocomial pathogen that has a high resistance to antimicrobials and dessication. In addition, it has a strong ability to form biofilm in chronic infections.
            In the present study, quantification of biofilm and screening of MDR A. baumannii for QS signal molecules (AHLs) were performed. Out of the 52 MDR Acinetobacter baumannii isolates, 42 isolates were found to be strong biofilm formers. Out of the 42 strong biofilm forming isolates, 20 isolates produced long chain AHL signals and none of them produced short chain AHL signals. The results revealed that 81% of the isolates formed strong biofilm and 48% of the strong biofilm forming isolated have QS activity, which indicates that QS has a potential role in the control of A. baumannii biofilm formation.