Distribution of virulence genes involved in biofilm formation in multi-drug resistant Acinetobacter baumannii clinical isolates

Acinetobacter baumannii is an opportunistic bacterial pathogen that is the major cause of hospital-acquired infections. It has been shown that A. baumannii with high biofilm formation increases the risk of acquiring infection. In this study, the prevalence of virulence genes involved in biofilm formation was determined in 225 A. baumannii clinical isolates from three hospitals in Thailand. Most of the isolates were multidrug-resistant A. baumannii strains (86.2%). Among all isolates, 76.9% (173/225) showed biofilm formation ability. The association between biofilm forming ability and gentamicin resistance was found (P < 0.05). The presence of virulence genes, epsA, bap, ompA, bfmS and blaPER-1 genes, was investigated by PCR. The prevalence of ompA, bfmS, bap, blaPER-1 and epsA genes among the isolated strains was 84.4%, 84%, 48%, 30.2%, respectively. Biofilm formation related genes, ompA and bap were associated with multidrug-resistant A. baumannii strains. The result of this study revealed that a high prevalence of biofilm-forming phenotypes among A. baumannii strains obtained from different hospitals. Effective strategies to prevent infection due to A. baumannii that produce biofilms are therefore needed. [Int Microbiol 19(2):121-129 (2016)]Keywords: Acinetobacter baumannii · biofilms · virulence gene