Molecular analysis of multi –drug resistant acintobacter baumannii isolated in baghdad hospital

Abstract

Qurum sense is regulatory systems that enable bacteria to expretion for a specific set of genes by making collective decisions and regulation of virulence factors of pathogenic Acintobacter baumannii, the prevalence of carbapenem resistance among (8) different antibiotic groups pattern. In the MDR index, all isolates showed high MDR, ranged from (6-21) antibiotics. MDR index is between (0.29-1.0).Quantitative biofilm production assay showed that 118/124(95.1%)of isolates were biofilm-formers. Detection of QS genes showed that (97.6%)121/124,(98.3%)122\124 and (4.8%)of isolates carried luxR, rhlI and rhIR genes, respectivelly. All isolates possess rhIR gene are isolated from child meningococcal patients and characterized by the strong biofilm formation. Identification of abaI gene in A.baumannii producing the QS signal molecules detected in124\124(100%). The current study revealed a strong relationship between Q.S genes luxR,rhII,rhIR and oxacillinases presence OXA23, OXA69. While a strong negative correlation between OXA48 and OXA69 with the rhIR gene. All isolates carried Integron I(n=124)(100%) with a significant presence of (luxR, rhII) genes, while INT2,3 had a highly significant level with rhIR. Noteworthy, (n=105) 84.7% of OXA51 positive isolates have carried ISAbal-blaOXA-51, whereas all isolates which have OXA23 carried ISAbal-blaOXA-23(n=65)52.4% most of them revealed IMP&MEM resistance phenotype. Insertion sequence(ISAbal-blaOXA-51) showed significant correlation with luxR, rhII genes, while there was no correlation among ISAbal25, ISAbal, ISAbal25-blaADC and luxR, rhII. Positive correlation recorded with all IS with rhIR, except ISAbal-blaADC.ads-a gene was observed in 77/124(62.1%) of isolates, which associated with aminoglycoside resistance, and included within the 93 XDR isolates. Studied isolates showed the same prevelance rate for ompA, smpA which was122\124(98.4%) of isolates.