Carbapenemase-producing Enterobacterales at Thong Nhat general hospital, Dong Nai province, Vietnam: Characterization by multiplex PCR and BD PhoenixTM M50

Abstract

Carbapenemase-producing Enterobacterales (CPE) are classified by the World Health Organization (WHO) as a Critical Priority pathogen group, posing a severe threat to global public health. Rapid and accurate detection and classification of carbapenemases are essential for optimizing antibiotic therapy and infection control. This cross-sectional descriptive study determined the prevalence of carbapenemase production and characterized carbapenemase genotypes, while assessing concordance between the BD Phoenix™ M50 system and multiplex polymerase chain reaction (PCR) among 278 clinical Enterobacterales isolates collected at Dong Nai Thong Nhat General Hospital from October 2024 to October 2025. All isolates were tested in parallel using the BD Phoenix™ M50 system (phenotypic carbapenemase class detection, NMIC-500 panel) and multiplex PCR targeting blaKPC, blaNDM, and blaOXA-48-like genes. Phenotypic screening identified carbapenemase production in 75.90% (211/278; 95% CI 70.5–80.6%) of isolates. Klebsiella pneumoniae was the predominant species (60.43%), followed by Escherichia coli (21.58%); endotracheal aspirates accounted for 54.68% of specimens. Multiplex PCR confirmed that 82.01% (228/278; 95% CI 77.1–86.1%) of isolates harbored at least one carbapenemase gene: blaNDM was most prevalent (47.84%), followed by blaOXA-48-like (23.02%) and blaKPC (8.99%). Co-carriage of two carbapenemase genes was detected in 2.16% (6/278) of isolates. The BD Phoenix™ M50 system demonstrated good overall concordance with multiplex PCR (Kappa = 0.72, p < 0.001), achieving a sensitivity of 90.4% (95% CI: 85.8–93.9%), specificity of 90.0% (95% CI: 78.2–96.7%), positive predictive value (PPV) of 97.6%, and an area under the receiver-operating characteristic curve (AUC) of 0.90. The system accurately classified Class B/NDM (86.47%) and Class A/KPC (84.0%) carbapenemases but showed limitations for Class D/OXA-48-like (62.5%). The BD Phoenix™ M50 system appears to be a useful high-throughput screening tool for routine CPE detection; however, molecular confirmation remains recommended for negative or unclassified phenotypic results, particularly when blaOXA-48-like infection is clinically suspected.