To evaluate the methicillin-resistant Staphylococcus aureus (MRSA) colonization in infants at neonatal intensive care unit (NICU) by active surveillance cultures (ASC) and the effects of mupirocin decolonization on MRSA infection.

Neonates adimitted to NICU of Ruian People's Hospital of Zhejiang Province, China between October 1, 2013 and September 30, 2014 underwent ASC within 24 hours of admission (ASC group). The samples from nasal vestibule and umbilicus were cultured for MRSA, and positive cultures were considered as MRSA colonization. These with negative cultures underwent repeated culture of MRSA by ASC at the 1st and 2nd week after NICU admission. Neonates admitted to NICU between October 1, 2014 and September 30, 2015 with MRSA colonization based on ASC were decolonized with mupirocin at both nasal vestibule and umbilicus twice daily for five consecutive days (decolonization group). Culture samples were obtained one day and one week after decolonization to repeat ASC. ASC was stopped if the subsequent culture was negative twice successively; and a second mupirocin decolonizaton was performed if the culture was positive. Chi-square test was used to compare the rates of colonization and infection between the two groups.

(1) MRSA colonization and infection in ASC group: MRSA colonization rates within 24 hours, and in the 1st and 2nd week after NICU admission in ASC group were 2.2% (9/418), 3.7% (15/402) and 3.6% (13/361), respectively. Compared with those without MRSA colonization, neonates with MRSA colonization had a higher incidence of MRSA infection [13.5% (5/37) vs 3.7% (14/381), χ²=7.524, P=0.006]. (2) MRSA colonization and infection in decolonization group: MRSA colonization rates within 24 hours, and at the 1st and 2nd week after NICU admission in decolonization group were 2.8% (12/435), 2.9% (12/414) and 1.3% (5/373), respectively. The MRSA colonization rate at the 2nd week was significantly lower than that in ASC group (χ²=3.919, P=0.048). Twenty-nine cases had MRSA colonization, among which, 27 cases were decolonized once and two cases were decolonized twice, and all were successful. The rate of MRSA infection in decolonization group was 2.1% (9/435), which was significantly lower than in ASC group [4.5% (19/418)] (χ²=4.118, P=0.042).

Rate of MRSA colonization is high at NICU. Mupirocin can decolonize MRSA carriage and reduce MRSA infection in neonates.

Intensive care units, neonatal; Methicillin-resistant staphylococcus aureus; Mupirocin; Staphylococcal infections; Watchful waiting