Etiología viral en la neumonía del adulto adquirida en la comunidad en un hospital del sur de Chile / Viral etiology of community acquired pneumonia among adults admitted to a general hospital

Background: There is paucity of information about viral etiology of community acquired pneumonia in adults. Aim: To investigate the viral etiology of pneumonia among hospitalized patients. Material and Methods: All adults with pneumonia that were hospitalized were prospectively enrolled at Puerto Montt hospital. A microbiological and viral assessment was carried out. Viral assessment included direct immunofluorescence of nasopharyngeal aspirates for influenza A and B virus and serum samples obtained during the acute phase of the disease and during convalescence for Hanta virus. Results: Between April 1 2005 and March 31 2006,159 adults aged 62 ± 20 years (58 % males), were admitted to the hospital for pneumonia. Mean hospital stay was 11.9 ± 8.6 days. Four patients had Hantavirus acute infection. Other viruses were identified in twelve patients (7.7%). Nine had influenza A, one syncytial respiratory virus, one syncytial and influenza A virus and one varicella zoster virus. Excluding patients with Hantavirus, no significant differences in age, clinical presentation, chest X ray findings, laboratory results and mortality were observed between patients with bacterial or viral etiology of the pneumonia. Conclusions: Viral etiology was confirmed in 10% of adult patients hospitalized with community acquired pneumonia.

Influenza: situación mundial y nacional / Influenza: global and national situation

Durante el año 2005, se notificaron 7.410 casos clínicos de influenza. La tasa nacional global corresponde a 634 casos por 100.000 hab., inferior en un 40 por ciento a lo observado a igual fecha del año 2004 (1.071 por 100.000 hab., y levemente superior a la tasa global de 2003 (513 por 100.000 hab.). Para el año 2005, el número de casos proyectados fue de 102.142 casos, mientras que la misma fecha de 2004 era de 170.885 casos. El incremento estacional se observó a partir de la semana 21, llegando a su máximo en la semana 25 (correspondiente a la tercera semana de junio), con una tasa de notificación de 60 casos por 100.000 hab., coincidiendo con el máximo de la detección viral. Este aumento duró 11 semanas, considerando las semanas con tasas superiores a 15 x 100.000 hab., disminuyendo con algunas oscilaciones a una tasa inferior a 3 x 100.000 hab., a fines de año. En el año 2004 el máximo de la notificación fue más precoz (semana 22), con una tasa de notificación semanal de 92 por 100.000 hab.

Estado inmunitario de 4 grupos de edad de población chilena contra sarampión y rubeola / Immune status against measles and rubella among chilean subjects of different ages

Background: Results of clinical and epidemiological studies confirm that no cases of measles have occurred in Chile since 1993. However, since covering of vaccination programs do not exceed 95 percent, an immunological surveillance for this disease is warranted. Aim: To know the immune status against measles and rubella in the Chilean population. Material and methods: A serological census of a representative sample of communities with high (90 percent or more) or low immunization coverings was performed. Four sub samples along the country were selected: 122 children aged 18 months of age (stratum A), 1,276 children attending the first year of basic school (stratum B), 899 teenagers in their last high school year (stratum C) and 399 women attending a family planning clinic (stratum D). IgG antibodies against measles and rubella were measured using ELISA and hemagglutination inhibition techniques, respectively. Results: Antibodies against measles and rubella were found in 96 percent and 94 percent of study subjects. No differences in these titres were found between different strata or communities with high or low vaccination covering. There is a high percentage of positive antibodies against measles among children of 18 months of age and a high percentage of antibodies against rubella among teenagers and women in family planning. Only 3 percent of the sample had not received any vaccine at the moment of the study. Conclusions: The high prevalence of antibodies against rubella allows to conclude that it is not necessary to consider this antigen in the next vaccination campaign. Due to the high prevalence of antibodies against measles, only the population older than 20 years old should be affected by the disease if this virus enters the country

Vigilancia de laboratorio en sarampión: Chile, 1992-1995 / Laboratory surveillance of measles: Chile, 1992-1995

Background: The first massive national measles vaccination campaign in Chile was done in 1992. Since then a laboratory surveillance of the disease has been undertaken at the Instituto de Salud Pública. Aim: To report the results of laboratory surveillance of measles between 1992 and 1995. Material and metbods: Paired serum samples from suspected cases of measles were received at the Institute. Measles specific IgG was determined with indirect immunofluorescence methods. IgG and IgM immunoenzymatic methods were used as complementary techiques, and rubella infections were ruled out by hemmaglutination inhibition tests. Results: Sera from 1087 presumptive cases (489 in 1992, 196 in 1993, 180 in 1994 and 222 in 1995) were analyzed. Only two cases of wild imported measles were confirmed, one in Arica in 1992 and the other in Santiago in 1993. Five additional post vaccine cases were detected. Eighty eight percent of samples in 1992 and 75 percent in 1994 were seropositive. A high percentage of cases were confirmed as rubella (55 percent in 1992 and 19 percent in 1994). Conclusions: Absence of wild measles virus circulation in Chile from 1992 to 1995 emphasizes the importance of laboratory surveillance of the disease

Estudio molecular de 6 episodios de infección intrahospitalaria causados por staphylococcus aureus meticilino-resistente / Molecular study of 6 episodes of intrahospitalary infection due to methicillin resistant staphylococcus aureus

A critical step in any epidemiologic research concerning nosocomial infections is the precise identification of the responsible pathogen. The present work utilized a molecular approach-plasmids identification, restriction lengght polymorphism DNA analysis and random amplified polymorphic DNA for the characterization of 6 nosocomial outbreaks due to 52 strains of methicillin-resistant staphylococcus aureus (MRSA). In these episodes, the clinic-epidemiologic and phenotipic analysis (antibiotype) pointed to a nosocomial infection. Through molecular analysis it was possible to establish in a very precise way, clonality due to MRSA strains in 2 of the studied outbreaks; the same type of analysis allowed to eliminate a MRSA clonal origin in the remainder 4 episodes. The antibiogram was not an useful analytic tool due to its poor discriminatory power. Also, through a PCR procedure, it was possible to identify the presence of the gen mecA in every of the 52 MRSA strains studied