Clin Microbiol Infect. 2021 Feb 12:S1198-743X(21)00077-X. doi: 10.1016/j.cmi.2021.02.002. Online ahead of print.
OBJECTIVES: Compared to cephalosporin-based prophylaxis, ertapenem prophylaxis lowers the risk of surgical site infection among carriers of extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) undergoing colorectal surgery. We aimed to determine whether ertapenem prophylaxis leads to increased post-operative colonization with carbapenem-resistant Enterobacterales (CRE) and third-generation cephalosporin-resistant Enterobacterales (3GCR-E).
METHODS: This study was nested within a quality improvement study of prophylaxis for ESBL-PE carriers undergoing colorectal surgery. Patients were screened 4-6 days after surgery for carriage of ESBL-PE or other 3GCR-E and CRE. When CRE were detected, pre- and post-surgical clones were compared using FT-IR spectroscopy.
RESULTS: The sample consisted of 56 patients who carried ESBL-PE before surgery and received cefuroxime/metronidazole prophylaxis (Group 1), 66 who carried ESBL-PE before surgery and received ertapenem (Group 2), and 103 ESBL-PE non-carriers who received cefuroxime/metronidazole prophylaxis (Group 3). CRE carriage was detected post-operatively in 1 patient (1.5%) in Group 2 versus 8 patients (14.3%) in Group 1 (RD:-12.8%; 95% CI:-22.4%- -3.1). For 7/9 patients, pre-operative ESBL-PE and post-operative CRE isolates were compared; in 5 of them, the pre- and post-operative clones were identical. Post-operative 3GCR-E carriage was detected in 37 patients (56.1%) in Group 2 versus 46 patients in Group 1 (82.1%) (aRD: -20.7%, 95% CI: -37.3%- -4.1%).
CONCLUSIONS: Among ESBL-PE carriers undergoing colorectal surgery, detection of short-term post-surgical colonization by CRE and 3GCR-E was significantly lower among patients who received ertapenem prophylaxis than those who received cephalosporin-metronidazole prophylaxis. Resistance development in a colonizing bacterial clone, rather than carbapenemase acquisition, was the major mechanism of carbapenem resistance.