Molecular Detection of Carbapenemase-Encoding Genes in Multidrug-Resistant Clinical Isolates in South Africa.

Introduction: Carbapenem-resistant has been responsible for an increasing number of hospital-acquired infections globally. The study investigated the prevalence of carbapenemase-encoding genes in clinical multidrug-resistant strains.

Materials And Methods: A total of 100 nonduplicate multidrug-resistant strains were cultured from clinical samples obtained from healthcare facilities in the O. R. Tambo district. The strains were confirmed by detecting the intrinsic gene. Antimicrobial susceptibility testing was performed by VITEK 2 and autoSCAN-4 systems. The MIC of imipenem and meropenem was rechecked by E-test. Colistin MIC was confirmed by the broth microdilution method. Real-time PCR was performed to investigate the presence of carbapenemase-encoding genes.

Results: Most strains showed high resistance rates (>80%) to the antibiotics tested. Resistance to amikacin, tetracycline, and tigecycline were 50%, 64%, and 48%, respectively. All strains were fully susceptible to colistin. The was detected in all strains whilst , , , , , and were found in 70%, 8%, 5%, 4%, 3%, and 2% of strains, respectively. None of the tested strains harboured the genes and . The coexistence of , and or was detected in 1% and 2% strains, respectively. A distinct feature of our findings was the coharbouring of the genes , and in 2% strains, and this is the first report in the Eastern Cape Province, South Africa. The 1 was carried in 80% of tested strains whilst IS1/ and IS1/ were detected in 15% and 40% of the strains, respectively. The detection of , IS1/ , IS1/ , and , , and carbapenemases in strains had a significant effect on both imipenem and meropenem MICs.

Conclusions: Results showed a high level of oxacillinases producing circulating in our study setting, highlighting the need for local molecular surveillance to inform appropriate management and prevention strategies.