Outbreak of New Delhi metallo-β-lactamase-1-producing Enterobacter cloacae in an acute care hospital general ward in Singapore.

BACKGROUND

Autochthonous infections with New Delhi metallo-β-lactamase-1 (NDM-1)-producing Enterobacteriaceae have been reported in Singapore since 2011, but occurrences of nosocomial transmission have not. We report an outbreak of NDM-1-producing Enterobacter cloacae among adults admitted to an acute hospital's general ward.

METHODS

On detecting the index case with a culture specimen positive for NDM-1-producing E cloacae, active case finding was conducted by screening all possible patient contacts. On-site ward assessment was performed, and electronic patient medical records were reviewed to conduct a case-control study to identify factors associated with colonization.

RESULTS

Of 55 screened patient contacts, 3 further cases were detected, with isolates genetically related to the index case. None of these 4 cases was housed within the same cubicle. However, 3 were managed by the same medical team. Being managed by this team was positively associated with being a case (adjusted odds ratio = 15.64; 95% confidence interval, 0.91-270.27; P = .06) after adjusting for age, sex, Charlson comorbidity index score, and recent antibiotic use.

CONCLUSION

Our report suggests nosocomial transmission of NDM-1-producing E cloacae occurred via health care staff. Improvements in infection control measures, especially pertaining to staff hand hygiene practices and ward staffing, are needed to reduce the spread of highly resistant pathogens, such as NDM-1-producing Enterobacteriaceae.