Epidemiological analysis of bacterial strains involved in hospital infection in a University Hospital from Brazil

RESUMO

Hospital infections cause an increase in morbidity and mortality of hospitalized patients with significant rise in hospital costs. The aim of this work was an epidemiological analysis of hospital infection cases occurred in a public University Hospital in Rio de Janeiro. Hence, 238 strains were isolated from 14 different clinical materials of 166 patients hospitalized in the period between August 1995 and July 1997. The average age of the patients was 33.4 years, 72.9 per cent used antimicrobials before having a positive culture. The most common risk conditions were surgery (19.3 per cent), positive HIV or AIDS (18.1 per cent) and lung disease (16.9 per cent). 24 different bacterial species were identified, S. aureus (21 per cent) and P. aeruginosa (18.5 per cent) were predominant. Among 50 S. aureus isolated strains 36 per cent were classified as MRSA (Methicillin Resistant S. aureus). The Gram negative bacteria presented high resistance to aminoglycosides and cephalosporins. A diarrhea outbreak, detected in high-risk neonatology ward, was caused by Salmonella serovar Infantis strain, with high antimicrobial resistance and a plasmid of high molecular weight (98Mda) containing virulence genes and positive for R factor.