NOSOCOMIAL OUTBREAK OF ESBL-PRODUCING ENTEROBACTER CLOACAE AMONG CARDIO-THORACIC SURGICAL PATIENTS: CAUSES AND CONSEQUENCES.

Background: The purpose of this report is to describe, investigate and evaluate the consequences of a nosocomial outbreak of extended-spectrum ß-lactamase (ESBL)-producing Enterobacter cloacae affecting cardio-thoracic surgery patients in a Belgian academic hospital.Methods: Cases were defined based on epidemiological and microbiological investigations, including molecular typing using repetitive element-based polymerase chain reaction (rep-PCR) and multilocus sequence typing (MLST). Case-control studies followed by field evaluations allowed the identification of a possible reservoir, and the retrospective assessment of human and financial consequences.Results: Over a three-month period, 42 patients were infected or colonized by CTX-M-15-producing E. cloacae strains that belonged to the same clonal lineage. Acquisition mainly occurred in the intensive care unit (n = 23) and in the cardio-thoracic surgery ward (n = 16). All but one patient had, before acquisition, undergone a cardio-thoracic surgical procedure, monitored by the same transoesophageal echocardiography (TOE) probe in the operating room. Despite negative microbiological culture results, the exclusion of the suspected probe resulted in rapid termination of the outbreak. Overall, the outbreak was associated with a high mortality rate among infected patients (40%) as well as major expenses (EUR 266 550).