MOLECULAR STUDY OF PSEUDOMONAS AERUGINOSA RESISTANCE ISOLATED FROM AL MUTHANNA HOSPITALS' WOUND AND BURN UNITS IN IRAQ

Objective: The aim of this study was to isolate the plasmid DNA of P. aeruginosa and to investigate the prevalence of resistance genes and their relationship to antibiotic resistance (aminoglycoside and β-lactam) in Al Muthanna hospitals in Iraq. Methods: The study included the collection of one hundred patients' samples from burn and wound swabs for the period from November 2021 to March 2022 from Al Muthanna hospitals in Iraq. Fifty-five bacterial isolates were obtained from wounds and burns and characterized and identified as P. aeruginosa using HiFluoro Pseudomonas agar Base and CHROM agar Pseudomonas as an enrichment selective medium as well as using biochemical tests. The susceptibility of P. aeruginosa isolates to aminoglycoside and β-lactam antibiotics was investigated according to the Clinical Laboratory Standards Institute (CLSI). P. aeruginosa plasmid was extracted. Polymerase chain reaction (PCR) was also carried out using P. aeruginosa plasmid DNA as a template to detect the presence/absence of the resistance genes using different pairs of specific primers. All PCR products of the positive isolates were sequenced for the detection of resistance genes by Macrogen Inc. in Seoul, South Korea. Results: P. aeruginosa produces various colors on Hifluoro agar media and CHROM agar Pseudomonas including blue green (pyocyanin), fluorescein greenYellow (pyoverdin) and red (Poyrubin). On the genetic side, using a plasmid purification kit to plasmid extraction for 55 of P. aeruginosa isolates we got 17 (30.9%) isolates showed plasmid. The aacA4 gene was identified in 1 (5.88%) of the plasmid- positive P. aeruginosa isolate. But, IMP-1 and OXA-2 not detected in this stud. Resistance to beta-lactam antibiotics may be due to the presence of resistance genes other than the IMP-1 and OXA-2 genes. It was not detected in this study using special primers. The susceptibility of P. aeruginosa isolates to aminoglycoside and β-lactam antibiotics was investigated. Most isolates showed high resistance degrees to penicillins group (ampicillin, pipercillin), cephalosporines group (ceftriaxone, cefotaxime), monobactams group (aztreonam), aminoglycosides group (gentamicin, streptomycin), but, it was moderately resistant to carbapenems group (meropenem and imipenem) and topramicin while, it was low resistance for β-lactamase inhibitor pipercillin/tazobactam, imipenem/EDTA. Sequencing analysis revealed of one plasmid type was Pseudomonas aeruginosa plasmid pCFF04 aacA4 gene contain on aacA4 gene for aminoglycoside resistance. This study therefore determined the prevalence, antibiotic resistance and plasmid patterns of P. aeruginosa strains from clinical specimens obtained from the wound and burn units of a Al Muthanna hospitals in Iraq.