[10-yearly monitoring of prevalence of MRSA and antibiotic usage in a neonatal intensive care unit].

From 1992 to 2001, we studied the prevalence of infants colonized MRSA and antibiotic usage for very-low-birth-weight infants in a neonatal intensive care unit at Asahikawa Kosei Hospital. We investigated nasopharyngeal swabs and stool samples every week after admission, and occasionally skin swabs, eye discharges and urines. Seventeen infants contracted nosocomial blood stream infection caused by MRSA which occurred between 1993 and 1996. Rate of infants colonized MRSA to all inpatients was 14.9% in 1992, which increased to 40.0% in 1994, and decreased to 7.1% in 2001. In each birth-weight group, rates of > or = 1,500 g, 1,000-1,499 g, and < 1,000 g infants were 6.5%, 45.0% and 60.0% in 1992, 24.5%, 100%, and 100% in 1994, 6.2%, 10.5%, and 21.4% in 2001. The longest period of antibiotic usage was 148.4 per 1000 patient-day in 1995 and decreased to 32.6 per 1,000 patient-day in 2001. The total value of antibiotics in 1995 was about yen 3,050,000, but in 2001 was about yen 470,000.