İnvaziv ve İnvaziv Olmayan Acinetobacter baumannii İzolatlarında Biyofilm Yapımı ve Virülans GenlerininVarlığı

Introduction: Biofilm production and as well as many virulence genes play an active role in the development of antibiotic resistance in A. baumannii. In this study, it was aimed to investigate biofilm production in multidrug-resistant A. baumannii isolates obtained from patients diagnosed with infection and the presence of the virulence genes (csuE and ompA) thought to play a role in biofilm production.Materials and Methods: This study was conducted on multi-drug resistant A. baumannii isolates obtained from patients hospitalized in Hacettepe University Hospital and diagnosed as having invasive/non-invasive infection. The identification of the species was carried out by conventional methods and MALDI-TOF MS. Biofilm production was determined by quantitative microplate biofilm method and the presence of the virulence genes csuE and ompA was determined using polymerase chain reaction method.Results: Among the 100 isolates included in this study, invasive A. baumannii clinical isolates (n= 17) were determined from catheter (n= 6), blood (n= 5), tissue (n= 2), nephrostomy urine specimen (n= 1), pleural fluid (n= 1), joint fluid (n= 1) and bile (n= 1) samples. Non-invasive isolates (n= 83) were obtained from deep tracheal aspirate (53%), pus (16%), sputum (13%) and urine (1%) samples. The presence of biofilm was determined in 99 of the isolates. It was determined that 52 of the isolates had strong, 31 had medium and 16 had weak positive biofilm production. Of the virulence genes examined, csuE was positive in 88 [non-invasive (n= 73), invasive (s= 15)] and the ompA gene was positive in 91 [non-invasive (s= 76), invasive (s= 15)] of the isolates. The presence of csuE and ompA virulence genes were detected in 47 of 52 isolates [non-invasive (n= 40), invasive (n= 12)] with strong biofilm production and in 25 of 31 isolates with medium biofilm production [non-invasive (n= 26), invasive (n= 5)].Conclusion: Biofilm production has been detected at a high rate in non-invasive isolates as well as in invasive A. baumannii isolates. In isolates with biofilm production, a high correlation was found between biofilm production and csuE gene which is a part of the pili formation system and ompA gene which encodes the ompA outer membrane porin protein. A. baumannii continues to pose a threat in nosocomial infections with high biofilm production and the presence of virulence genes in multidrug-resistant non-invasive isolates.