Molecular evaluation of colistin-resistant gene expression changes in Acinetobacter baumannii with real-time polymerase chain reaction

• Published in: Infection and drug resistance 2017-01, Vol.10, p.455-462
• Main Authors: Sepahvand, Shahriar, Davarpanah, Mohammad Ali, Roudgari, Amir, Bahador, Abbas, Karbasizade, Vajihe, Kargar Jahromi, Zahra
• Format: Article
• Language: English
• Subjects: Acinetobacter baumannii; Acquired immune deficiency syndrome; AIDS; Antibiotic resistance; Antibiotics; Bacteria; Colistin; Deoxyribonucleic acid; DNA; DNA polymerase; Dosage and administration; Drug resistance; Epidemiology; Gene expression; Genetic aspects; Hospitals; Immune system; Infectious diseases; Intensive care units; Microbial drug resistance; Microorganisms; Nosocomial infection; Nosocomial infections; Original Research; Pathogens; PCR; Peptides; Polymerase chain reaction; Real Time PCR; Strains (organisms); Trauma
• ISSN: 1178-6973; 1178-6973
• DOI: 10.2147/IDR.S141196

is an important human pathogen which has recently gained increased attention due to the occurrence of drug-resistant nosocomial infections in patients suffering from immune system disorders, and those in hospital intensive care units. The aim of this research was to identify and isolate strains resistant to colistin, determine antibiotic resistance pattern of this bacteria, investigate the presence of colistin-resistant genes, and finally assess the effect of expression changes in pmrA and pmrB genes resistant to against colistin via real-time polymerase chain reaction. The samples were initially purified and isolated using biochemical tests and Micro-gen kit. Later, the resistance pattern evaluation of validated samples to different antibiotics and colistin was carried out using two methods viz., disc diffusion and E-test. This was followed by the assessment of genes resistant to colistin via polymerase chain reaction besides gene expression changes via real-time polymerase chain reaction. The results of this study indicated that eleven strains of isolated from Shahid Rajaee Trauma Hospital were resistant to colistin. However, in the resistance pattern evaluation of isolated from Ali Asghar Hospital, all the strains were sensitive to colistin. In the evaluation of genes resistant to pmrA and pmrB, most of the strains resistant to colistin were carriers of these genes. Besides, in the expression assessment of these genes, it was demonstrated that expression of pmrA in the strains resistant to colistin significantly increased in relation to sensitive strains, but the expression of pmrB increased at a lower rate in the strains resistant to colistin as compared to the sensitive strains. Thus, it can be safely mentioned that increased expression of pmrA was due to the resistance of to colistin.