Prevalence of carbapenemase genes among multidrug-resistant Pseudomonas aeruginosa isolates from tertiary care centers in Southern Thailand

Objectives: To assess the prevalence of carbapenemase genes among multidrug-resistant Pseudomonas aeruginosa (P. aeruginosa) isolates from tertiary care centers in Southern Thailand.

Methods: The prevalence of carbapenemase genes in P. aeruginosa isolates collected from patients hospitalized between 2015-2017 in 2 tertiary care hospitals in Songkhla Province, Southern Thailand, was investigated. Standard laboratory procedures were followed and disk diffusion test was used for bacterial identification and susceptibility evaluations. Carbapenemase genes were detected using multiplex polymerase chain reaction (PCR) and genotyping by pulsed field gel electrophoresis.

Results: Among the 289 P. aeruginosa isolates, 55% was from sputum, 19.4% was from urine, and 8% was from secretions. The prevalence was 55.7% in carbapenem-resistant multidrug-resistant P. aeruginosa (CR-MDR-PA) and 39.4% in multidrug-resistant P. aeruginosa (MDR-PA). Resistance to imipenem, meropenem, gentamicin, and ceftazidime ranged from 50-60%, and amikacin was the most effective antibiotic (38.4%). The carbapenemase genes bla_VIM (27.7%), bla_IMP (23.9%), and bla_OXA48 (4.8%) were detected; however, bla_SPM and bla_BIC were not detected in any of the isolates. Pulsed field gel electrophoresis analysis revealed clonal diversity among 17 CR-MDR-PA strains.

Conclusion: A high percentage of CR-MDR-PA carries carbapenemase genes in our area; therefore, more emphasis on and application of molecular techniques for infection prevention and control may provide useful insights on disease epidemiology.