National nosocomial infections study

National nosocomial infections study A nosocomial infection rate of 356.6 per 10,000 patients discharged, or 3.5?,0,was reported in hospitals participating in the National Nosocomial Infections Study from 1975 to 1976. The rate of nosocomial infection has not changed markedly since 1974 when the last data were collected. According to the report published in the Center for Disease Control's Morbidity and Mortality Weekly Repofl, a total of 92,001 infections in 2,579,668 patients were reported by 83 hospitals in 31 states during the two-year period. The lowest rates of infection were reported by community hospitals and the highest by municipal and county hospitals. Rates of infection varied according to hospital services. Pediatric services reported a rate of 1.O% and newborn nurseries, 1.5%. Rates of 1.9%, 3.1%, 3.7%, and 5.0% were reported in obstetrical, gynecological, medical, and surgical services respectively. The most common site of nosocomial infection was the urinary tract, which accounted for 53% of medical service infections, 38% on the surgical services, and 17% on pediatric services. Surgical wound infections, the next highest rate, accounted for 33% of infections on surgical services. Lower respiratory infections were responsible for a 21'lo infection rate on medical services and a rate of 15% in surgical services. Upper respiratory infections were significantly fewer on medical and surgical services-accounting for 1% to 2% of infections-while a rate of 5.5% was reported in pediatric services. Isolated nosocomial gastroenteritis rarely occurred, but clusters of the infection were occasionally reported. Sixty-two percent of all cases occurred on pediatric services or in newborn nurseries. Bacteremias in the study were classified as 1148

primary or secondary. Primary bacteremia, reported at a rate of 14.7 per 10,000 discharges, was defined as "bacterial infection of the blood with no other site on the patient infected with the same pathogen before onset of the blood infection." Secondary bacteremia, "infection of the blood bacteriologically, temporally, and clinically related to an infection at another site on the patient," was recorded at a rate of 15.1. Rates of bacteremia varied according to the type of hospital. For example, the occurrence of primary bacteremia ranged from 6.3 in community hospitals to 28.7 in municipal hospitals to 29.1 in university hospitals. Secondary bacteremia rates ranged from 6.3 in community hospitals to 36.9 in municipal hospitals to 25.9 in university hospitals. Primarily associated with urinary tract infections, lower respiratory infections, and surgical wounds, secondary bacteremia occurred with 4.4% of all nosocomial infections recorded in the study. The report notes, however, that "this figure ranged from 6.4% in pediatric services to 5.1'10 on medical, 4.3% on surgical, and 1.2% on gynecological services.'' A high rate of bacteremia was also associated with intraabdominal infections and in burn wounds. The study reported that 91.3% of the recorded infections were cultured and that six groups of pathogens were responsible for 70.8% of all infections. They are Escherichia coli (21.4%), Staphylococcus aureus (11.3%), Streptococcus group D (1O.8%), Psevdomonas species (10.1" l o ) , Proteus species (18.7%), and Klebsiella species (8.5%). In secondary bacteremia, E coli, S aureus, Klebsiella pneumoniae, Proteus species, S pneumoniae, Enterobacter species, Serratia species, and Bacteroides were most frequently identified.

AORN Journal, May 1978, Vol 27, N o 6