[Epidemiological study of Staphylococcus aureus nasal carriage in senior centers]. / Estudio epidemiológico de portadores nasales de Staphylococcus aureus en centros de mayores.

The observation of an increasing number of methicillin-resistant Staphylococcus aureus (MRSA) isolates in some population groups prompted us to study the risk factors and the epidemiological profile of S. aureus nasal carriage in healthy adults 65 years of age and older residing in the province of Segovia. Attention was particularly focused on the possibility that some of the infections were community-acquired. We conducted a prospective and observational study of people who usually visited senior citizen centers in the province of Segovia (Carbonero, Cuéllar, Cantalejo) and its capital. The analysis period took place between January and May 2003. Infections were classified as community-acquired, hospital-acquired or health-care associated. Isolates of methicillin-resistant (MRSA) and methicillin-susceptible S. aureus (MSSA) were studied by pulsed-field gel electrophoresis (PFGE). There were 34 (19.5%) The prevalence of nasal carriage of S. aureus was 19.5% and that for MRSA was 1.1%. Female sex was significantly associated with the carriage state. All S. aureus isolates were mupirocin-susceptible. 100% susceptibility and specificity was obtained through latex agglutination testing. The molecular study showed that the transmission for MRSA was monoclonal and that for MSSA was more policlonal. The results presented here form the basis for similar studies in other Spanish senior citizen centers and provide evidence that MRSA strains are beginning to circulate and are becoming significantly established within the community, thus highlighting the need for implementing control strategies to prevent dissemination.

Estudio epidemiológico de portadores nasales de Staphylococcus aureus en centros de mayores / Epidemiological study of Staphylococcus aureus nasal carriage in senior people centers

El aparente incremento en el número de aislamientos de Staphylococcus aureus resistentes a la meticilina (SARM) de origen comunitario en algunos grupos de población nos llevó a estudiar los factores de riesgo y el perfil epidemiológico de los portadores nasales de S. aureus de edad ≥ 65 años, sanos y autónomos, de la comunidad de Segovia. Se estudió con especial atención su posible origen comunitario. Se realizó un estudio prospectivo y observacional con personas que acudían habitualmente a los Centros de Mayores pertenecientes a Segovia capital y provincia (Carbonero, Cuéllar, Cantalejo). El periodo de estudio fue de enero a mayo de 2003. Se distinguió entre adquisición intrahospitalaria y extrahospitalaria (adquirida en la comunidad). Los aislamientos tanto de SARM como de SAMS (S. aureus sensible a la meticilina) se estudiaron mediante electroforesis en campo pulsante (ECP). La prevalencia de portadores nasales de S. aureus fue del 19,5% y de SARM del 1,1%. El sexo femenino se asoció de manera significativa con el estado de portador. El 100% de los aislamientos de S. aureus fueron sensibles a la mupirocina. Se obtuvo un 100% de sensibilidad y especificidad con la prueba de aglutinación en látex sobre soporte. El estudio molecular de las cepas de SARM mostró que la transmisión fue monoclonal; sin embargo, en el caso de los SAMS la transmisión resultó ser más policlonal. Nuestros resultados sientan las bases para emprender estudios similares en otros Centros de Mayores españoles, y proporcionan pruebas acerca de la posibilidad de que empiecen a circular cepas de SARM y se establezcan de forma importante en la comunidad, señalando así la necesidad de establecer estrategias de control para prevenir tal diseminación

The observation of an increasing number of methicillin-resistant Staphylococcus aureus (MRSA) isolates in some population groups prompted us to study the risk factors and the epidemiological profile of S. aureus nasal carriage in healthy adults 65 years of age and older residing in the province of Segovia. Attention was particularly focused on the possibility that some of the infections were community-acquired. We conducted a prospective and observational study of people who usually visited senior citizen centers in the province of Segovia (Carbonero, Cuéllar, Cantalejo) and its capital. The analysis period took place between January and May 2003. Infections were classified as community-acquired, hospital-acquired or health-care associated. Isolates of methicillin-resistant (MRSA) and methicillin-susceptible S. aureus (MSSA) were studied by pulsed-field gel electrophoresis (PFGE). There were 34 (19.5%) The prevalence of nasal carriage of S. aureus was 19.5% and that for MRSA was 1.1%. Female sex was significantly associated with the carriage state. All S. aureus isolates were mupirocin-susceptible. 100% susceptibility and specificity was obtained through latex agglutination testing. The molecular study showed that the transmission for MRSA was monoclonal and that for MSSA was more policlonal. The results presented here form the basis for similar studies in other Spanish senior citizen centers and provide evidence that MRSA strains are beginning to circulate and are becoming significantly established within the community, thus highlighting the need for implementing control strategies to prevent dissemination