Characterization of nosocomial outbreak of multiresistant bacteria IN intensive care units

Abstract

The rates of mortality and morbidity of nosocomial infectious diseases are equally or more important than those of pneumonia, diarrhea and meningitis. The National Nosocomial Infection Surveillance System (NNIS) was begun in 1970, and it was created by the Center for Disease Control (CDC) in the United States, where hospitals treating acute illness in adults and children, clinical or surgical use this system. It is estimated that in Brazil the incidence of nosocomial infections reaches a value exceeding 1.2 million per month. Since 1983, the Ministry of Health has established a national program for control of nosocomial infection (CCIH). Although the majority of Brazilian hospitals have formally constituted committees of hospital infection control there are few centers that develop an effective program for this purpose. It was agreed that a comprehensive infection control needs a microbiology laboratory equipped with methodologies that allow accurate identification of microorganisms, detection of new and emerging mechanisms of antimicrobial resistance and molecular typing of pathogenic microorganisms. Molecular biology has become an important tool in the prevention of nosocomial infection, as well as enabling the tracking of outbreaks, allows determination of resistance genes to microorganisms involved in nosocomial infections. The surveillance can be passive or active, the latter being more efficient because it anticipates the emergence of outbreaks. From 2005 to 2009 were identified 732 nosocomial infections in adult ICU of HU-USP. The top 3 sites were pneumonia followed by urinary tract and bloodstream. Regarding etiology, it were identified two or more pathogens in 56 infections and a single pathogen in 401 infections. Among of all nosocomial infections, 38% remained without etiology identified. A total of 522 pathogens were identified, belonging to 32 different species. The top 6 pathogens for different sites were Acinetobacter baumannii (18% of isolates), following by Staphylococcus aureus (16%), Pseudomonas aeruginosa (15%) Candida albicans (9%) Candida tropicalis (5%) and Escherichia coli (5%). The aims of this study are identified and characterize the bacterial strains isolated from nosocomial infections using molecular tools. Moreover, characterize the different clones from patients admitted to different hospital areas. Establishing clonality of pathogens can aid in the identification of the source (environmental or personnel) of organisms, distinguish infectious from noninfectious strains, and distinguish relapse from re-infection. The establishment of a molecular laboratory for the surveillance of nosocomial infections in the HU-USP will be very important to the NIS program. Moreover, in the future, this laboratory could be reference in epidemiological surveillance studies of nosocomial infections for SUS-hospitals network. (AU)