NEW APPROACHES TO REDUCE STAPHYLOCOCCUS-AUREUS NOSOCOMIAL INFECTION-RATES - TREATING STAPHYLOCOCCUS-AUREUS NASAL CARRIAGE

BACKGROUND: Nosocomial infections cause significant patient morbidity and mortality. The 2.5 million nosocomial infections that occur each y ear cost the US healthcare system $5 million to $10 million. Staphyloc occus aureus has long been recognized as an important pathogen in huma n disease and is the most common cause of nosocomial infections. OBJEC TIVE: TO describe the epidemiology of S. aureus nosocomial infections that are attributable to patients' endogenous colonisation. DATA SOURC ES: Review of the English-language literature and a MEDLINE search (as of September 1997). DATA SYNTHESIS: The ecologic niche of S, aureus i s the anterior nares. The prevalence of S. aureus nasal carriage is ap proximately 20-25%, but varies among different populations, and is inf luenced by age, underlying illness, race, certain behaviors, and the e nvironment in which the person lives or works. The link between S, aur eus nasal carriage and development of subsequent S. aureus infections has been established in patients on hemodialysis, on continuous ambula tory peritoneal dialysis, and those undergoing surgery. S. aureus nasa l carriers have a two-to tenfold increased risk of developing S, aureu s surgical site or intravenous catheter infections. Thirty percent to 100% of S. aureus infections are due to endogenous flora and infecting strains were genetically identical to nasal strains. Three treatment strategies may eliminate nasal carriage: locally applied antibiotics o r disinfectants, systemic antibiotics, and bacterial interference. Amo ng these strategies, locally applied or systemic antibiotics are most commonly used. Nasal ointments or sprays and oral antibiotics have var iable efficacy and their use frequently results in antimicrobial resis tance among S, aureus strains, Of the commonly used agents, mupirocin (pseudomonic acid) ointment has been shown to be 97% effective in redu cing S. aureus nasal carriage. However, resistance occurs when the oin tment has been applied for a prolonged period over large surface areas . CONCLUSIONS: Given the importance of S. aureus nosocomial infections and the increased risk of S. aureus nasal carriage in patients with n osocomial infections, investigators need to study cost effective strat egies to prevent certain types of nosocomial infections or nosocomial infections that occur in specific settings. One potential strategy is to decrease S. aureus nasal carriage among certain patient populations .