Development and validation of a multiplex TaqMan real-time PCR for rapid detection of genes encoding four types of class D carbapenemase in Acinetobacter baumannii

• Published in: Journal of medical microbiology Vol. 61; no. 11; pp. 1532 - 1537
• Main Authors: HUANG, Xiao-Zhe, CASH, Dana M, CHAHINE, Mohamad A, NIKOLICH, Mikeljon P, CRAFT, David W
• Format: Journal Article
• Language: English
• Published: Reading Society for General Microbiology 01-11-2012
• Subjects: Acinetobacter baumannii - drug effects; Acinetobacter baumannii - enzymology; Acinetobacter Infections - microbiology; Anti-Bacterial Agents - pharmacology; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; beta-Lactamases - genetics; beta-Lactamases - metabolism; Biological and medical sciences; Drug Resistance, Bacterial - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Bacterial - physiology; Gene Expression Regulation, Enzymologic - physiology; Humans; Infectious diseases; Medical sciences; Microbiology; Miscellaneous; Real-Time Polymerase Chain Reaction - methods; Real-Time Polymerase Chain Reaction - standards; Reproducibility of Results; Sensitivity and Specificity; Acinetobacter baumannii; Rapid technique; Gene; Multiplex polymerase chain reaction; Neisseriaceae; Carbapenemase; Bacteria; Micrococcales; Real time
• ISSN: 0022-2615; 1473-5644
• DOI: 10.1099/jmm.0.045823-0

A multiplex TaqMan real-time PCR to detect carbapenem-hydrolysing class D β-lactamases (bla(OXA-23)-like, bla(OXA-24/40)-like, bla(OXA-51)-like and bla(OXA-58)-like genes) was developed and evaluated for early detection of imipenem (IMP) resistance in clinically significant Acinetobacter baumannii isolates. Well-characterized strains of A. baumannii were used as positive controls and non-Acinetobacter strains were used to assess specificity. Analytical sensitivity was quantified by comparison with the number of bacterial c.f.u. Forty of 46 (87 %) clinically significant and IMP-resistant A. baumannii isolates were positive for the bla(OXA-23)-like gene, and one isolate (2 %) was positive for the bla(OXA-58)-like gene. The bla(OXA-24/40)-like gene was not detected in any of the 46 IMP-resistant strains and the bla(OXA-51)-like gene was identified in both IMP-resistant and non-resistant A. baumannii. All 11 non-Acinetobacter bacteria produced a negative result for each of the four bla(OXA) genes. This assay was able to detect as few as 10 c.f.u. per assay. This real-time PCR method demonstrated rapid detection of OXA-like carbapenem resistance in A. baumannii in comparison with phenotypic susceptibility testing methodology. This method could be adapted to a multiplexed single reaction for rapid detection of genes associated with carbapenem resistance in A. baumannii and potentially other clinically significant multidrug-resistant Gram-negative bacteria.