Biofilm Formation and Drug Resistance Pattern of Acinetobacter Baumannii Isolated from Clinical Specimens

Abstract

Acinetobacter baumannii has emerged as a leading cause of no socomial infections as they are capable to evolve resistance to various classes of antibiotics including carbapenems. The capacity of A. baumannii to form biofilm might be associated with increased antibiotic resistance and hence treatment failure. A cross-sectional study was carried with objective to associate the biofilm formation with the drug resistance pattern of A. baumannii and to detect blaOXA-23, blaOXA-24 and blaOXA-51 genes from phenotypic carbapenem resistant A. baumannii. A total of 180 clinical specimens including wound swab, pus, blood, urine, sputum, catheter tips,tissue, body fluidwere collected from study population, identified by microbiological procedures including Gram’s staining, culture and various biochemical tests. The biofilm production was determined by using quantitative adherence assay. Antimicrobial susceptibility test were carried out by modified Kirby-Bauer disc diffusion method following Clinical and laboratory Standards Insitiute CLSI guidelines 2019 while screening for Carbapenemase production was checked through Modified Hodge Test (MHT). All the phenotypically positive Carbapenem producers were subjected to molecular detection of the target resistant genes Polymerase chain reaction techniques. Out of 180 clinical specimens, 92 (51.11%) showed bacterial growth however,only 19 (20.65%) were identified asA. baumannii. Among all A.baumanniiisolates 16 (84.21%) were multi-drug resistant and 12 (63.16%) were carbapenem resistant. The blaOXA-51gene was detected in all isolates whereas, blaOXA-23 gene was detected in only 12 (63.16%) isolates butblaOXA-24 gene was not detected in any of isolates. Among total, 17 (89.47%) A. baumannii produced biofilm with 9 (47.37%) strong biofilm producers.The association between biofilm production and drug resistance was statistically significant.This study showed that most of A. baumannii isolates had a high level of antibiotic resistance and had a capacity to produce biofilm.This study provided valuable clue for management ofA. baumanniinfections in clinical settings. Key words: A. baumannii, Wound, Cather tips, Tissue, Pus, Blood, Urine Sputum, BodyFluid, MDR, blaOXA genes,biofilm formation.