Study of biofilm formation and molecular detection of antimicrobial resistance among the clinical isolates of Acinetobacter baumannii

Background and Aim : Acinetobacter baumannii is a nonfermentative Gram-negative and non-motile rod. This bacterium is broadly found in intensive care units (ICUs) and can cause various hospital-acquired infections including urinary tract infection, bacteremia, burn wound infection, bloodstream infection, and respiratory tract infection. Unfortunately, an arising dilemma with A. baumannii is acquiring resistance to almost all regularly used antibiotics including ß-lactam agents, aminoglycosides, fluoroquinolones and Tetracyclines. This study was aimed to evaluate the presence of aminoglycosides and tetracycline resistance encoding genes and biofilm formation ability among clinical isolates of A. baumannii in intensive care units in the northMethods : A. baumannii isolates were collected from various sources of hospitalized patients in ICUs. Antibiotic susceptibility test was per formed by disk-diffusion method as recommended by the (CLSI-M۱۰۰-S۲۸). The bacterial whole genome was extracted by the boiling method. we studied three major MDR A. baumannii genes, including efflux pumps (tetA), aminoglycoside-modifying enzymes (aacC۱, aadB, aacC۲, aphA۶, aadA۱, aacA۴) and biofilm-related genes (csuE and ompA). The mi crotiter plate assay was used to determine the biofilm formation.Results : Of ۵۹ A. baumannii isolates, ۳۳.۹% were resistant to Doxycycline and ۹۸.۳% were resistance to gentamicin. The frequency rate of resistance genes was ۷۶.۳%, ۰%, ۷۸%, ۴۴.۱%, ۲۸.۸%,۱۶.۹%, ۴.۳%, ۰%, ۹۸.۳% and ۹۴.۳% for tetB, tetA, aacA۴, aphA۶, aadB, aadA۱, aacC۲, aacC۱, csuE and ompA respectively. All isolates were biofilm producers.Conclusion : Our results revealed a significant diversity of resistance genes in our region. Dissimilar types of genes are carried by clinical isolates of A.baumannii in ICUs; so, it is necessary to isolate and detect precisely to reduce their severe consequences and patients mortality rate

کلیدواژه ها:

A.baumannii ، multidrug-resistant bacteria (MDR) ، aminoglycoside-modifying enzymes (AMEs) ، tetracycline resistant ، Biofilm