ISSN : 2146-3123
E-ISSN : 2146-3131

Resistance Genes and Mortality in Carbapenem-resistant Klebsiella pneumoniae Bacteremias: Effects of the COVID-19 Pandemic
Ahmet Furkan Kurt1, Elif Seren Tanrıverdi2, Metin Yalçın1, Osman Faruk Bayramlar3, Sibel Yıldız Kaya1, Rıdvan Karaali1, Mert Ahmet Kuşkucu4,5, Fatma Köksal Çakırlar6, Barış Otlu7, İlker İnanç Balkan1, Bilgül Mete1, Gökhan Aygün1, Fehmi Tabak1, Neşe Saltoğlu1
1Department of Infectious Diseases and Clinical Microbiology, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Türkiye
2Microbiology Laboratory Unit, Malatya Training and Research Hospital, Malatya, Türkiye
3Department of Public Health, Bakırköy District Health Directorate, İstanbul, Türkiye
4Department of Medical Microbiology, Koç University School of Medicine, İstanbul, Türkiye
5Koç University İsbank Center for Infectious Diseases, İstanbul, Türkiye
6Department of Medical Microbiology, İstanbul University-Cerrahpaşa, Cerrahpaşa Faculty of Medicine, İstanbul, Türkiye
7Department of Medical Microbiology, İnönü University Faculty of Medicine, Malatya, Türkiye
DOI : 10.4274/balkanmedj.galenos.2024.2024-5-99
Pages : 357-368

Abstract

Background: Emerging carbapenem-resistant Klebsiella pneumoniae (K. pneumoniae) (CRKP) bacteremias are presenting significant public health risks due to limited treatment options and increased mortality. K. pneumoniae isolates exhibit carbapenem resistance rates that vary from 25% to 50% throughout the European continent, including our country.
Aims: To assess the characteristics of CRKP bacteremia, a condition that has recently demonstrated an increasing prevalence in our center. We sought to ascertain the resistance rates of isolated strains to antibiotics other than carbapenems, identify the responsible carbapenemase genes, evaluate the efficacy of antibiotics, determine mortality rates, explore clonality among strains, and investigate the influence of the COVID-19 pandemic on all these factors.
Study Design: Retrospective observational study.
Methods: This study included patients aged 18 and older who had experienced meropenem-resistant K. pneumoniae bacteremia. Meropenem resistance was confirmed by employing the Kirby-Bauer disk diffusion method. Meropenem minimum inhibitory concentration (MIC) levels were determined using the gradient test, while colistin MIC levels were ascertained using the disk elution technique. Carbapenemase genes were evaluated via colony polymerase chain reaction (PCR), and clonality analysis was performed using the arbitrarily primed PCR technique.
Results: The study comprised 230 patients, with a mean age of 63.1 ± 15.9 years, of whom 58.7% were male. Oxacillinase-48 (OXA-48) was detected in 74.8% of the patients, New Delhi metallo-beta-lactamase (NDM) in 12.6%, OXA-48 + NDM in 7.8%, and KPC in 4.8%. The 14-day and 30-day mortality rates were 57% and 69.6%, respectively. Multivariate analysis of the 30-day mortality revealed several crucial factors, including bacteremia development in the intensive care unit, the occurrence of bacteremia during the COVID-19 pandemic, polymicrobial bacteremia, the use of indwelling intravenous catheters, a platelet count of ≤ 140,000/µl, procalcitonin levels of ≥ 6 µg/l, and a Charlson comorbidity score ≥ 3. Notably, the OXA-48 and KPC genes were upregulated significantly during the COVID-19 pandemic, while the NDM gene groups were downregulated. Additionally, both 14-day and 30-day mortality rates increased significantly.
Conclusion: In this study, the most prevalent carbapenemase gene was OXA-48; however, there has been a recent increase in KPC genes. No dominant epidemic strain was identified through clonality analysis. The clustering rate was 68% before the pandemic, increasing to 85.7% during the pandemic. The significance of infection control measures is underscored by the rise in both clustering and mortality rates during the COVID-19 pandemic.

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