Serratia marcescens outbreak in a neonatology unit of a Spanish tertiary hospital: Risk factors and control measures.

•We describe a prolonged Serratia marcescens outbreak in a neonatology unit.•To control the outbreak, we implemented a gradual multidisciplinary approach.•The environmental source remained unclear.•Hands of health care personnel seemed to act as the main mechanism of transmission.•Cessation of admissions, dedicated personnel, and exclusive location were crucial.