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

• Published in: American journal of infection control 2019-03, Vol.47 (3), p.271-279
• Main Authors: Redondo-Bravo, Lidia, Gutiérrez-González, Enrique, San Juan-Sanz, Isabel, Fernández-Jiménez, Inés, Ruiz-Carrascoso, Guillermo, Gallego-Lombardo, Sara, Sánchez-García, Laura, Elorza-Fernández, Dolores, Pellicer-Martínez, Adelina, Omeñaca, Félix, Robustillo-Rodela, Ana
• Format: Article
• Language: English
• Subjects: Case-Control Studies; Colonization; Disease outbreak; Disease Outbreaks; Disease Transmission, Infectious - prevention & control; Environmental Microbiology; Female; Hospital Departments; Humans; Infant, Newborn; Infection; Infection control; Infection Control - methods; Infection Control - organization & administration; Intensive care unit; Male; Microbiological Techniques; Neonatology; Pharynx - microbiology; Pregnancy; Rectum - microbiology; Risk Factors; Serratia Infections - epidemiology; Serratia Infections - prevention & control; Serratia marcescens; Serratia marcescens - isolation & purification; Spain - epidemiology; Tertiary Care Centers
• ISSN: 0196-6553; 1527-3296
• DOI: 10.1016/j.ajic.2018.08.026

•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. We describe the investigation undertaken and the measures adopted to control a Serratia marcescens outbreak in the neonatology unit of La Paz University Hospital in Madrid, Spain. Weekly rectal and pharyngeal screenings for S marcescens were performed in the neonates starting after detection of the outbreak. Environmental samples and samples from health care workers (HCWs) were obtained for microbiological analysis. An unmatched case-control study was carried out to investigate risk factors for infection/colonization. The outbreak began in June 2016 and ended in March 2017, affecting a total of 59 neonates. Twenty-five (42.37%) neonates sustained an infection, most frequently conjunctivitis and sepsis. Multivariate logistic regression identified the following risk factors: parenteral nutrition (odds ratio [OR], 103.4; 95% confidence interval [CI], 11.9-894.8), history of previous radiography (OR, 15.3; 95% CI, 2.4-95.6), and prematurity (OR, 5.65; 95% CI, 1.5-21.8). Various measures were adopted to control the outbreak, such as strict contact precautions, daily multidisciplinary team meetings, cohorting, allocation of dedicated staff, unit disinfection, and partial closure. Hands of HCWs were the main suspected mechanism of transmission, based on the inconclusive results of the environmental investigation and the high number of HCWs and procedures performed in the unit. S marcescens spreads easily in neonatology units, mainly in neonatal intensive care units, and is often difficult to control, requiring a multidisciplinary approach. Strict measures, including cohorting and medical attention by exclusive staff, are often needed to get these outbreaks under control.