Multiplex PCR for identification and β-lactam resistance gene detection in clinical isolates of Acinetobacter baumannii

Abstract

Introduction: Acinetobacter baumannii (A. baumannii) is a major cause of hospital-acquired infections and frequently harbors antibiotic-resistance genes that complicate treatment. Rapid identification and resistance gene detection are essential for effective antibiotic use and infection control. This study developed a multiplex polymerase chain reaction (PCR) assay to identify A. baumannii and detect key β-lactam resistance genes for clinical isolates.

Methodology: The assay targeted the recA gene and the 16S-23S ribosomal RNA internal transcribed spacer region for A. baumannii identification. In addition, five β-lactamase genes (bla_OXA-51-like, ampC, bla_CTX-M, bla_TEM, and bla_SHV) were targeted. Antimicrobial susceptibility testing and phenotypic extended-spectrum beta-lactamase detection were performed to confirm resistance profiles.

Results: Of the 49 Acinetobacter isolates, 46 were identified as A. baumannii by multiplex PCR. All 46 isolates contained ampC, and 45 harbored bla_OXA-51-like. bla_TEM was detected in 34 isolates, whereas bla_CTX-M and bla_SHV were absent. Phenotypic tests showed general agreement with the PCR results. High resistance rates were observed for multiple antibiotic classes, including carbapenems, cephalosporins, and aminoglycosides.

Conclusions: The multiplex PCR assay developed here provides a rapid and reliable method for A. baumannii identification and resistance gene detection, outperforming conventional methods in terms of speed and accuracy. The high resistance rates observed highlight the urgent need for effective diagnostic tools and infection control strategies to combat multidrug-resistant A. baumannii.