Molecular detection of carbapenemase genes in WHO priority pathogens from blood cultures of sepsis patients in Pakistan.

Aims

This study aimed to assess the antibiogram patterns of CR-GNB and to characterize carbapenemase-encoding genes among isolates obtained from patients with sepsis.

Methods

A total of 3,746 blood culture samples were collected from patients with suspected septicemia and samples were processed using the BACTEC blood culture system, and all positive cultures were sub-cultured onto blood agar and MacConkey agar plates for isolation. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK 2 compact system following CLSI guidelines. Detection of antimicrobial resistance genes was carried out by PCR using gene-specific primers.

Results

Of 3,746 blood cultures, 873 (23.3%) were positive, yielding 577 (66.1%) Gram-negative isolates. Among these, 212 (24.3%) were CR-GNB, predominantly A. baumannii (41.5%), and K. pneumoniae (21.2%). MIC of meropenem among CR-GNB isolates ranged from >128 µg/mL to <1024 µg/ml. Overall, 47.2% of isolates were inhibited at 624µg/mL, followed by 38.2% at 312 µg/mL, and 12.7% at 156 µg/ml. In CR-A. baumannii, blaOXA-23 and blaNDM were detected in 71.6% and 62.5% of isolates, respectively. blaNDM was also present in K. pneumoniae (43.8%), and E. coli (40.7%).   .

Conclusion

There was a high prevalence of CR-GNB among septicemia patients, emphasizing the need for strict infection control measures to prevent their spread.