Detection of carbapenem resistance in ESBL-positive and carbapenemase-producing Klebsiella pneumoniae strains using phenotypic and molecular methods

Kayin B., UYAR Y., AYGÜN G., YAŞAR ARSU H., CAN G., KÜÇÜKBASMACI Ö.

ANNALS OF CLINICAL AND ANALYTICAL MEDICINE, vol.17, no.7, pp.676-680, 2026 (ESCI)

Abstract

Aim: Antimicrobial resistance is a major global and national health concern. Carbapenem-resistant Klebsiella pneumoniae (CRKP) ranks at the top of the WHO 2024 list. K. pneumoniae causes significant morbidity and mortality among ICU patients. This study aimed to detect carbapenemase enzymes (KPC, NDM, OXA-48, and VIM) in carbapenem-resistant and ESBL-positive K. pneumoniae strains isolated from respiratory and blood samples using PCR. Methods: Samples from 75 ICU patients hospitalized at Cerrahpa & scedil;a Medical Faculty Hospital in 2023 were analyzed. Respiratory tract (BAL, ETA, sputum) and blood cultures were processed using conventional methods (Blood agar, Chromoagar, MIO medium) and automated systems (Vitek 2 Compact, MALDI-TOF). Isolates were stored at-80 degrees C, subcultured, and subjected to DNA extraction. Carbapenemase genes (KPC, NDM, OXA-48, VIM) were identified by Real-Time PCR. Results: Of the 75 patients, 62.7% were male, with a mean age of 62.6 +/- 18.3 years. Respiratory tract samples comprised 56%, and blood cultures 44%. Resistance rates were 52% for imipenem and 90.7% for meropenem. Gene prevalence was NDM 92%, OXA-48 84%, KPC 81.3%, and VIM 78.7%. Coexistence patterns included KPC + OXA-48 + NDM + VIM (70.7%) and OXA-48 + NDM (8%). No carbapenemase genes were detected in 5.3% of isolates. No significant differences were found by gender, age, or ICU type (p>0.05). Conclusion: ICU infections caused by carbapenemase-producing K. pneumoniae pose a serious risk. Regular surveillance of carbapenemaseproducing bacteria is crucial for infection control and antimicrobial stewardship.