Trends in post-operative infections by Gram-positive bacteria

Surgical patients are now more prone than ever to have a post-operative infection. On average, they are now older and more have chronic disease histories with reduced immunocompetence or iatrogenic immunosuppression, and many undergo more aggressive, more complex surgical procedures. Moreover, the infectious agents have changed. A comparison of data collected by the SENTRY Antimicrobial Surveillance Program for the years 1988 and 1998 from North and Latin America and Europe shows important shifts in the nature of the infectious agents. Among the Gram-positive agents, Staphylococcus aureus was the most frequent isolate in both years, but its share has more than doubled. Beta-hemolytic streptococci increased their share from 3 to 5% while enterococci fell from 13 to 8%. Perhaps more important than the shifts in incidence are dramatic changes in the antimicrobial resistance patterns of these agents. Data from the past several years show increasing resistance for the drugs that were previously considered 'first line' treatment for post-surgical infections. The majority of S. aureus and coagulase-negative staphylococci are now resistant to most classes of antibiotics. Antimicrobial resistance is beginning to be detected in beta-hemolytic streptococci, and vancomycin-resistant enterococci, which were not even reported in 1987-1988, now represent 17% of all enterococci isolated in the USA and Canada. To stay ahead in the fight against surgical infections, we must react in a combination of ways, using disinfection, prophylaxis, new antibiotics and, above all, we must practice superb hospital infection control and world-wide antimicrobial epidemiology studies.