Extensively drug-resistant ESBL-producing enterobacterales and coexisting antimicrobial resistance genes are associated with mortality in critically ill patients with cancer.

ESBL-producing bacteria are a problem in patients with cancer. The emergence of XDR phenotypes with ESBLs increases mortality. We aimed to evaluate ESBL-producing bacteria, the prevalence of MDR and XDR phenotypes, ESBL genes, and mortality predictors in patients with cancer in the ICU. Different clinical cultures were collected from patients in oncology ICUs. We used the VITEK2 system to identify isolates and assess antibiotic sensitivity, and the combination disk method to detect ESBL phenotypes. β-lactamase, ESBL, and carbapenem genes were detected using PCR. 136 isolates were ESBL-producing. Respiratory cultures were the main source, followed by blood cultures. K. pneumoniae was the most common, followed by E. coli. Isolates showed high resistance to third- and fourth-generation cephalosporins and carbapenem antibiotics. 84.6% and 13.2% of isolates were XDR and MDR, respectively. The most harbored genes were SHV and TEM (94.1%), CTXM-15 (59.6%), SHV-12 (67.6%), and NDM (78.7%). 38.2% of isolates harbored seven β-lactamase, ESBL, and carbapenem genes. K. pneumoniae significantly harbored more ESBL and carbapenem genes than E. coli. Patient age, relapses, and hospital stay are predictors of mortality in patients. An improved surveillance program and antibiotic stewardship are urgently needed.