Phenotypic and genotypic detection of carbapenem resistance and carbapenemase production in <em>Enterobacterales</em> isolates from cancer patients at the National Cancer Institute, Sri Lanka

Introduction: The emergence of pathogens that are resistant to most of the antibiotics including carba-penems are alarmingly increasing and becoming a major global threat, especially among immunocompromised patients. Presently it has become a major health chal-lenge to treat these patients as carbapenems are one of the last resort antibiotics. The main aim of this study was to detect carbapenemase production and its prevalence among Enterobacterales isolates from clinical samples of cancer patients.Methodology: Enterobacterales isolates from clinical samples received to Laboratory of Microbiology in National Cancer Institute, Sri Lanka were subjected to antibiotic sensitivity testing according to CLSI method. CarbaNP test was carried out on carbapenem non susceptible and intermediate susceptible isolates. Pathogen identification up to species level was done using the VITEK® 2 Compact system. The genotypic detection on selected isolates was carried out using the Xpert Carba-R assay.Results: The prevalence of carbapenem resistant Enterobacterales among the study isolates was 46.1%(n=48). Isolates that showed either carbapenem resistance or intermediate susceptibility (n=58) on initial testing were subjected to Carba NP test. Out of 58 carbapenem non susceptible isolates 63.8% (n=37) were positive for CarbaNP test indicating carbapenemase production. Among carbapenemase producing isolates, Klebsiella pneumoniae spp pneumoniae was found to be the most prevalent pathogen. Genetic testing on randomly selected samples showed most of them were co-harboring both blaOXA-48 and blaNDM.Conclusions: The prevalence of carbapenem resistance is notably high among cancer patients in Sri Lanka. Therefore, detecting carbapenemase-producing genes is crucial for optimizing antibiotic management. Addi-tionally, reinforcing antibiotic stewardship is necessary. Given the already high levels of carbapenem resistance, exploring and ensuring the availability of alternative treatment options within the country is essential.