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