672. Report of a Multi-species Outbreak of VIM-producing Carbapenem-resistant Organisms in a Burn Unit and Subsequent Experience Using Novel β-lactam Antibiotics for Treatment


 
 
 The incidence of carbapenem-resistant organisms (CROs) has increased over the past 3 decades. Carbapenem-resistance due to metallo-β-lactamases (MBLs) such as the Verona integron-encoded metallo-β-lactamase (VIM) are particularly problematic due to the limited treatment options. We describe a multi-species outbreak of VIM-producing CROs (VIM CROs) in a tertiary care hospital along with our experience using novel β-lactam antibiotics for treatment.
 
 
 
 We performed a retrospective chart review after a cluster of patients in the burn unit of a tertiary care hospital were found to have infections with VIM CROs. Electronic medical records for all patients with a VIM CRO isolated between November 2021 and March 2022 were reviewed. Data regarding patient characteristics, antimicrobial use, culture results, antimicrobial susceptibility testing, and clinical outcomes were recorded for each patient.
 
 
 
 8 patients were found to have VIM-mediated CRO burn wound infections, 5 of whom were also bacteremic with a VIM CRO. A VIM gene was identified in 5 different species (Pseudomonas aeruginosa and 4 Enterobacterales). None of the patients received carbapenems prior to isolation of a CRO. Among the 5 patients treated with cefiderocol, 2 had cefiderocol-resistant VIM CROs isolated 10-20 days after starting cefiderocol. 3 patients received the combination of ceftazidime/avibactam and aztreonam, and all had subsequent clearing of their CRO infection on follow-up cultures taken from the same site. Only one of the 8 patients died within 30 days of initial CRO isolation, after developing a subsequent fungal infection. The median Pitt bacteremia score at the time of initial CRO isolation was 1 (range 0-4) in the 7 patients who survived versus a score of 6 in the patient who died.
 
 
 
 MBLs such as VIM have the potential for multi-species spread throughout hospital units even in the absence of carbapenem selection pressure. Although over 60% of the patients in this study had bacteremia and cefiderocol-resistance developed in 40% of the patients treated with cefiderocol, mortality was fortunately low in this group. While newer β-lactam antibiotics remain an exciting addition to our armamentarium, we must remain diligent in monitoring for rapid development of resistance.
 
 
 
 Thomas R. Talbot, III, MD, MPH, OmniSolve: Board Member Romney Humphries, PhD, D(ABMM), M(ASCP), Accelerate: Advisor/Consultant|Accelerate: Stocks/Bonds|bioMerieux: Advisor/Consultant|IHMA: Advisor/Consultant|Pattern: Advisor/Consultant|Qiagen: Advisor/Consultant|QPex: Advisor/Consultant|Roche: Advisor/Consultant|Specific Diagnostics: Advisor/Consultant|Specific Diagnostics: Stocks/Bonds|ThermoFisher: Advisor/Consultant|Torus: Advisor/Consultant.
