Identification and Frequency of Colistin-Resistant Acintobacter Baumanii in Clinical Isolates Using Polymerase Chain Reaction

Document Type : Original Article (s)

Authors

1 MSc Student, Department of Microbiology, School of Biology, Islamic Azad University, Falavarjan Branch, Isfahan, Iran

2 Assistant Professor, Department of Microbiology, School of Biology, Falavarjan Branch, Islamic Azad University, Isfahan, Iran

3 Associate Professor, Department of Microbiology, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran

Abstract

Background: Antibiotic resistance among bacterial agents causing nosocomial infections is increasing. Acinetobacter baumannii is one of these agents that its increasing resistance to commonly used antibiotics makes it difficult to treat such infections. The aim of this study was to identify Acinetobacter baumannii isolates from clinical specimens using polymerase chain reaction (PCR) method and to determine relative frequency of colistin-resistant isolates.Methods: In a period of 7 months, 96 clinical specimens were isolated. All isolates were identified as Acinetobacter baumannii via standard biochemical tests and amplification of blaoxa-51 gene. To determine phenotypic resistance of isolates toward colistin, colony screening method was used and also minimum inhibitory concentration (MIC) of colistin was determined via broth microdilution.Findings: 51 isolates (53.1%) were resistant to colistin phenotypically and the minimum inhibitory concentration level for colistin resistant strains was more than 128 µg/ml.Conclusion: Based on our findings, the relative frequency of colistin-resistant Acinetobacter baumannii isolates was high. Therefore, more supervision and controlled use of this antibiotic is necessary; more infection control measurements are necessary to be done.

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