Ceftazidime-Avibactam resistance in clinical isolates of carbapenem-resistant Klebsiella pneumoniae: A phenotypic and genotypic analysis.

OBJECTIVE

To find the prevalence of Ceftazidime-Avibactam (CAZ-AVI) resistant Klebsiella pneumoniae in clinical isolates and to determine the genes responsible for Ceftazidime-Avibactam resistance using PCR.

METHODS

A total of 89 carbapenem resistant Klebsiella pneumoniae from various clinical samples were included in the study. CAZ-AVI resistance was tested using E-test. CAZ-AVI resistant strains were subjected to conventional PCR for detection of carbapenamase genes bla, bla, bla, bla, bla.

RESULTS

Of the 89 isolates screened for CAZ-AVI resistance, 45(50.5%) isolates were found to be resistant. 42 isolates were subjected to PCR for detection of β lactamase genes.34 isolates were positive for bla and all 42 isolates were positive for bla. Co-expression of NDM-1 and OXA-48 was seen in 34 isolates. Sensitivity of mCIM test to identify a carbapenamse compared to PCR was 61.9%. Sensitivity of eCIM test to identify NDM-1 was 80%.

CONCLUSION

CAZ-AVI was effective in vitro in 49.4% of the isolates. Indicating that CAZ-AVI is a promising addition to antibiotics against CRE as well as a carbapenem sparing drug in ESBL producing organisms. β-Lactamase-related mutations are the main mechanism leading to CAZ-AVI resistance.