The aim of our work is to study and evaluate a rapid method for detection of Klebsiella pneumonia carbapenemases genes (blaKPC) in enterobacteriaceae isolates from clinical samples by using real time PCR and comparison of this method with ordinary phenotypic methods. Outbreaks of carbapenemâ€resistant enterobacteriaceae (CRE), primarily K. pneumoniae, have been reported recently in several regions worldwide. The production of carbapenemases especially K. pneumoniae carbapenemase (KPC) is the most important mechanism of enzymatic resistance in enterobacteriaceae. One hundred and fifty clinical isolates from different departments of Menoufia university hospitals were tested by both disc diffusion method (Imipenem 10 μg, Meropenem 10 μg and Ertapenem 10 μg), and imipenem E-test for minimum inhibitory concentration (MIC) then analyzed according to cut off-points of CLSI 2014 guideline. Then all the one hundred fifty clinical isolates were tested for the presence of a blaKPC gene by real time PCR. We found Eighty three (83) isolates (55.3%) from 150 were resistant to one or more carbapenems by disk diffusion method, and 88 isolates (58.7%) were resistant by E test while 91 isolates (60.6%) were positive for the presence of KPC gene by real time PCR. There was significant difference between disk diffusion method and real-time PCR (P < 0.001) and E test and real-time PCR (P < 0.001) regarding carbapenem resistance. The highest percent of enterobacteriaceae isolates having KPC gene were among K .pneumoniae (46.1%). KPC positive cases were mainly (74.1%) from urology department. About (97.8%) blaKPC PCR positive cases had been exposed to invasive procedures such as mechanical ventilation (P < 0.001), and (95.6%) blaKPC PCR positive cases had been from hospital acquired infections (P < 0.001). There was a history of antimicrobial intake in 70.3% of cases infected with KPC PCR positive isolates. blaKPC PCR has sensitivity ,specificity, negative predictive value, and diagnostic accuracy (99, 87, 98 and 93%), respectively .
Key words: carbapenemâ€resistant enterobacteriaceae (CRE), real time PCR, blaKPC.
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