A hospital-wide outbreak of IMI-17-producing Enterobacter ludwigii in an Israeli hospital

Background: To describe the course and intervention of an hospital-wide IMI-Producing Enterobacter ludwigii outbreak. Methods: This was an outbreak interventional study, done at a tertiary care center in Tel-Aviv, Israel. Data was collected on the course of the outbreak and the demographic and clinical characteristics of all patients involved in the outbreak. The intervention measures included patients’ cohorting, contact isolation precautions, environmental cleaning and screening of contacts. The molecular features and phylogeny of outbreak-related isolates were studied by whole-genome based analysis. Results: The outbreak included 34 patients that were colonized by IMI-Producing E. ludwigii and were identified in 24 wards throughout the hospital. Colonization was identified in the first 72 h of admission in 13/34 patients (38.2%). Most patients (91.2%) were admitted from home and had relatively low level of comorbidities. The majority of them (88%) had no recent use of invasive catheters and none had previous carriage of other multi-drug resistant bacteria. All available isolates harbored the bla_IMI-17 allele and belonged to Sequence-Type 385. With the exception of two isolates, all isolates were closely related with less than a 20-SNP difference between them. Conclusions: This outbreak had most likely originated in the community and subsequently disseminated inside our institution. More studies are required in order to elucidate the epidemiology of IMI-Producing E. ludwigii and the possible role of environmental sources in its dissemination.