Conventional and Real-Time PCR Targeting blaOXA Genes as Reliable Methods for a Rapid Detection of Carbapenem-Resistant Acinetobacter baumannii Clinical Strains

Multidrug-resistant Acinetobacter baumannii, particularly those producing carbapenemases, are spread worldwide. A reliable detection of carbapenemases is essential to choose the appropriate antimicrobial therapy and, consequently, prevent the dissemination of carbapenem-resistant strains. The aim of this study is to examine the molecular basis of the carbapenem resistance mechanism and estimation of conventional PCR and real-time PCR usefulness for the detection of oxacillinases when compared to phenotypic carbapenemases detection. The following methods were evaluated: the CarbAcineto NP test, Carbapenem Inactivation Method, CPO panels of semiautomated antimicrobial susceptibility testing method on the BD Phoenix (TM) M50 system, conventional Polymerase Chain Reaction and real-time PCR. The eazyplex (R) SuperBug complete A assay was used as the reference method. Among the tested strains, 39 (67.2%) carried the bla(OXA-40) gene, while the bla(OXA-23) gene was noted amongst 19 (32.8%) isolates. The diagnostic sensitivities of the studied assays were as follows: CarbAcineto NP-65.5%; CIM-100%; CPO-100%; conventional PCR-100%; real-time PCR-100%.

Automated summary

This study aimed to evaluate different detection methods for carbapenemases and found that both conventional PCR and real-time PCR showed high sensitivity in detecting carbapenem-resistant strains, making them valuable tools for accurate diagnosis.