Community transmission of multidrug-resistant tuberculosis is associated with activity space overlap in Lima, Peru.

BACKGROUND: Transmission of multidrug-resistant tuberculosis (MDRTB) requires spatial proximity between infectious cases and susceptible persons. We assess activity space overlap among MDRTB cases and community controls to identify potential areas of transmission. METHODS: We enrolled 35 MDRTB cases and 64 TB-free community controls in Lima, Peru. Cases were whole genome sequenced and strain clustering was used as a proxy for transmission. GPS data were gathered from participants over seven days. Kernel density estimation methods were used to construct activity spaces from GPS locations and the utilization distribution overlap index (UDOI) was used to quantify activity space overlap. RESULTS: Activity spaces of controls (median = 35.6 km2, IQR = 25.1-54) were larger than cases (median = 21.3 km2, IQR = 17.9-48.6) (P = 0.02). Activity space overlap was greatest among genetically clustered cases (mean UDOI = 0.63, sd = 0.67) and lowest between cases and controls (mean UDOI = 0.13, sd = 0.28). UDOI was positively associated with genetic similarity of MDRTB strains between case pairs (P < 0.001). The odds of two cases being genetically clustered increased by 22% per 0.10 increase in UDOI (OR = 1.22, CI = 1.09-1.36, P < 0.001). CONCLUSIONS: Activity space overlap is associated with MDRTB clustering. MDRTB transmission may be occurring in small, overlapping activity spaces in community settings. GPS studies may be useful in identifying new areas of MDRTB transmission.

Tracking the onset date of the community spread of SARS-CoV-2 in western countries.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the world during 2020, but the precise time in which the virus began to spread locally is difficult to trace for most countries. Here, we estimate the probable onset date of the community spread of SARS-CoV-2 for heavily affected countries from Western Europe and the Americas on the basis of the cumulative number of deaths reported during the early stage of the epidemic. Our results support that SARS-CoV-2 probably started to spread locally in all western countries analysed between mid-January and mid-February 2020, thus long before community transmission was officially recognised and control measures were implemented.

Tuberculosis infantil en Cuba / Children tuberculosis in Cuba

Introducción: La presencia de tuberculosis infantil constituye una señal de alerta de transmisión en la comunidad. Objetivos: Determinar incidencia y características de la tuberculosis infantil en Cuba en su etapa más reciente. Métodos: Estudio descriptivo, transversal y retrospectivo de los 107 casos diagnosticados 0-18 años, periodo 2013-2017, según datos de la Dirección de Registros Médicos y Estadísticas de Salud, la ficha epidemiológica y datos del Centro de Referencia Nacional de tuberculosis infantil. Se estudiaron variables demográficas, epidemiológicas, clínicas y de estudios que contribuyeron al diagnóstico, así como a la evolución final de los casos. Resultados: Predominó el grupo de edad de 15 - 18 años (52,0 - 48,6 por ciento) , sexo masculino (59,0-55,1 por ciento) y los procedentes de La Habana (43,0 - 40,2 por ciento). La tuberculosis en menores de 19 años representó entre 1,8 y 4,4 por ciento del total de casos en el país. La tasa de incidencia por 100 mil habitantes se comportó en menores de 15 años entre 0,4 y 0,8 con tendencia descendente; en el grupo 15-18 años, entre 0,8 y 3,0 con tendencia ascendente. Predominaron las formas pulmonares (87,0 - 82,6 por ciento) con pobre confirmación bacteriológica (49,0 - 45,7 por ciento). Ningún caso tuvo coinfección VIH-TB ni drogorresistencia. Hubo una fallecida (0,9 por ciento). Conclusiones: Cuba tiene muy baja incidencia de tuberculosis infantil, no es un problema de salud, pero sí un indicador de transmisión de la enfermedad en la comunidad. Para su eliminación, hay que fortalecer las acciones del Programa Nacional de Control, particularmente en La Habana y en el grupo de edad de 15 a 18 años(AU)

Introduction: The presence of children tuberculosis constitutes a transmission alert sign in the community. Objectives: To determine the incidence and characteristics of children tuberculosis in Cuba in its earliest stage. Methods: Descriptive, cross-sectional and restrospective study of 107 diagnosed cases in the ages from 0 to 18 years during the period 2013-2017, according to data provided by the National Division of Medical Records and Health Statistics, epidemiological records and data from the Center of National Reference on Children Tuberculosis. There were studied demographic, epidemiological, clinical and study variables which contributed to the diagnosis as well as to the final evolution of the cases. Results: There was a predominance of the age of group of 15 - 18 years (52.0 - 48.6 percent), masculine sex (59.0 - 55.1 percent) and patients from Havana city (43.0 - 40.2 percent). Tuberculosis in patients under 19 years represented between the 1.8 and 4.4 percent of all the cases in the country. The incidence rate per 100 000 inhabitants in patients under 15 years was 0.4 to 0.8 with a decreasing trend; in the group age of 15 to 18 years it was between 0.8 and 3.0 with an increasing trend. Pulmonary conditions predominated (87.0 - 82.6 percent) with poor bacteriological confirmation (49.0 - 45.7 percent). None of the cases had HIV-TB co-infection nor drugs resistance. There was one deceased girl (0,9 percent). Conclusions: Cuba has a very low incidence of children tuberculosis; it does not represent a health problem but it actually is an indicator of transmission of the disease in the community. For its erradication, it is needed to strenght the actions of the Control´s National Program, particularly in Havana city and the age group of 15 to 18 years(AU)

Revisión rápida del uso de cubrebocas quirúrgicos en ámbito comunitario e infecciones respiratorias agudas / Rapid review of the community-wide use of surgical masks and acute respiratory infections

Resumen: Objetivo: Evaluar la efectividad del uso de cubrebocas quirúrgico en ámbitos comunitarios para reducir la probabilidad de contagio por SARS-CoV-2 u otra infección respiratoria aguda viral, en comparación con no usar cubrebocas. Material y métodos: Se utilizó la metodología de revisiones rápidas de Cochrane. La estrategia de búsqueda abarcó una base de datos académica y pre-prints hasta el 1 de abril de 2020. Los títulos y resúmenes fueron revisados por un investigador. La revisión de textos completos fue dividida entre tres investigadores. Los resultados fueron sintetizados de forma narrativa. Resultados: Se identificaron 713 manuscritos, de los cuales 21 cumplieron los criterios de inclusión. De seis revisiones sistemáticas, cuatro no encontraron reducciones en la probabilidad de contagio y seis estudios experimentales en hogares no encontraron diferencias en la probabilidad de contagio asociado con el uso de cubrebocas. Únicamente un estudio de modelaje estimó una reducción de 20% en la incidencia de enfermedad respiratoria, asumiendo que 10 a 50% de la población hace uso correcto de cubrebocas quirúrgicos. Conclusiones: La evidencia científica no es concluyente para recomendar o desalentar el uso de cubrebocas a nivel poblacional. Considerando los potenciales efectos negativos, las recomendaciones gubernamentales deberían esperar a los resultados de los experimentos naturales en países que han recomendado la utilización poblacional de cubrebocas.

Abstract: Objective: To assess the effectiveness of using surgical masks in community settings to reduce the probability of infection by SARS-CoV-2 or other acute viral respiratory infection, compared to not using surgical masks. Materials and methods: We followed the Cochrane rapid review methodology. The search strategy encompasses one academic database and pre-prints until April 1, 2020. Titles and abstracts were reviewed by one investigator. The full text review was divided among three researchers. The results were synthesized in a narrative way. Result: 713 manuscripts were identified, of which 21 met the inclusion criteria. Of six systematic reviews, four found no reduction in the probability of transmission. Experimental home studies found no differences in the probability of contagion associated with the use of mouth masks. Only one modeling study estimated a 20% reduction in the incidence of acute respiratory disease, assuming that 10 to 50% of the population use the surgical masks correctly. Conclusions: The scientific evidence is inconclusive to recommend or discourage the use of surgical masks at the population level. Considering the potential negative effects, official recommendations should await for the results of natural experiments currently occurring in countries that have recommended the use of face masks at the population level.

[Rapid review of the use of community-wide surgical masks and acute respiratory infections]. / Revisión rápida del uso de cubrebocas quirúrgicos en ámbito comunitario e infecciones respiratorias agudas.

OBJECTIVE: To assess the effectiveness of using surgical masks in community settings to reduce the probability of infection by SARS-CoV-2 or other acute viral respiratory infection, compared to not using surgical masks. MATERIALS AND METHODS: We followed the Cochrane rapid review methodology. The search strategy encompasses one academic database and pre-prints until April 1, 2020. Titles and abstracts were reviewed by one investigator. The full text review was divided among three researchers. The results were synthesized in a narrative way. RESULTS: 713 manuscripts were identified, of which 21 met the inclusion criteria. Of six systematic reviews, four found no reduction in the probability of transmission. Experimental home studies found no differences in the probability of contagion associated with the use of mouth masks. Only one modeling study estimated a 20% reduction in the incidence of acute respiratory disease, assuming that 10 to 50% of the population use the surgical masks correctly. CONCLUSIONS: The scientific evidence is inconclusive to recommend or discourage the use of surgical masks at the population level. Considering the potential negative effects, official recommendations should await for the results of natural experiments currently occurring in countries that have recommended the use of face masks at the population level.

OBJETIVO: Evaluar la efectividad del uso de cubrebocas quirúrgico en ámbitos comunitarios para reducir la probabilidad de contagio por SARS-CoV-2 u otra infección respiratoria aguda viral, en comparación con no usar cubrebocas. MATERIAL Y MÉTODOS: Se utilizó la metodología de revisiones rápidas de Cochrane. La estrategia de búsqueda abarcó una base de datos académica y pre-prints hasta el 1 de abril de 2020. Los títulos y resúmenes fueron revisados por un investigador. La revisión de textos completos fue dividida entre tres investigadores. Los resultados fueron sintetizados de forma narrativa. RESULTADOS: Se identificaron 713 manuscritos, de los cuales 21 cumplieron los criterios de inclusión. De seis revisiones sistemáticas, cuatro no encontraron reducciones en la probabilidad de contagio y seis estudios experimentales en hogares no encontraron diferencias en la probabilidad de contagio asociado con el uso de cubrebocas. Únicamente un estudio de modelaje estimó una reducción de 20% en la incidencia de enfermedad respiratoria, asumiendo que 10 a 50% de la población hace uso correcto de cubrebocas quirúrgicos. CONCLUSIONES: La evidencia científica no es concluyente para recomendar o desalentar el uso de cubrebocas a nivel poblacional. Considerando los potenciales efectos negativos, las recomendaciones gubernamentales deberían esperar a los resultados de los experimentos naturales en países que han recomendado la utilización poblacional de cubrebocas.

Tracking the onset date of the community spread of SARS-CoV-2 in western countries

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapidly spread around the world during 2020, but the precise time in which the virus began to spread locally is difficult to trace for most countries. Here, we estimate the probable onset date of the community spread of SARS-CoV-2 for heavily affected countries from Western Europe and the Americas on the basis of the cumulative number of deaths reported during the early stage of the epidemic. Our results support that SARS-CoV-2 probably started to spread locally in all western countries analysed between mid-January and mid-February 2020, thus long before community transmission was officially recognised and control measures were implemented.

Evaluating strategies for control of tuberculosis in prisons and prevention of spillover into communities: An observational and modeling study from Brazil.

BACKGROUND: It has been hypothesized that prisons serve as amplifiers of general tuberculosis (TB) epidemics, but there is a paucity of data on this phenomenon and the potential population-level effects of prison-focused interventions. This study (1) quantifies the TB risk for prisoners as they traverse incarceration and release, (2) mathematically models the impact of prison-based interventions on TB burden in the general population, and (3) generalizes this model to a wide range of epidemiological contexts. METHODS AND FINDINGS: We obtained individual-level incarceration data for all inmates (n = 42,925) and all reported TB cases (n = 5,643) in the Brazilian state of Mato Grosso do Sul from 2007 through 2013. We matched individuals between prisoner and TB databases and estimated the incidence of TB from the time of incarceration and the time of prison release using Cox proportional hazards models. We identified 130 new TB cases diagnosed during incarceration and 170 among individuals released from prison. During imprisonment, TB rates increased from 111 cases per 100,000 person-years at entry to a maximum of 1,303 per 100,000 person-years at 5.2 years. At release, TB incidence was 229 per 100,000 person-years, which declined to 42 per 100,000 person-years (the average TB incidence in Brazil) after 7 years. We used these data to populate a compartmental model of TB transmission and incarceration to evaluate the effects of various prison-based interventions on the incidence of TB among prisoners and the general population. Annual mass TB screening within Brazilian prisons would reduce TB incidence in prisons by 47.4% (95% Bayesian credible interval [BCI], 44.4%-52.5%) and in the general population by 19.4% (95% BCI 17.9%-24.2%). A generalized model demonstrates that prison-based interventions would have maximum effectiveness in reducing community incidence in populations with a high concentration of TB in prisons and greater degrees of mixing between ex-prisoners and community members. Study limitations include our focus on a single Brazilian state and our retrospective use of administrative databases. CONCLUSIONS: Our findings suggest that the prison environment, more so than the prison population itself, drives TB incidence, and targeted interventions within prisons could have a substantial effect on the broader TB epidemic.

[Relationship between crowding and community acquired skin and soft tissues infections]. / Relación entre hacinamiento e infecciones comunitarias de piel y partes blandas.

The association of the spread of community infections with poverty and overcrowding is well known. In our hospital, located in José C. Paz, we assist sporadic cases of post-cesarean infections caused by community acquired methicillin-resistant Staphylococcus aureus (CaMRSA). In a prospective study of families treated at our hospital, we investigated the relationship between a history of skin and soft tissue infections (SSTI) and extreme overcrowding defined as households with unsatisfied basic needs type 3 (NBI 3). A total of 264 households were included in the study; 109 (41.3%) had a history of SSTI and 59 (22.3%) were NBI 3. A total of 61.0% of the NBI 3 households and 35.6% of the non-NBI 3 households reported SSTI (p = 0.00047). Using Google Maps, we georeferenced households and identified them on a NBI map adapted from the 2010 demographic census. In neighborhoods with NBI > 9.7%, 51.2% of the households had a history of SSTI. When NBI was < 9.7%, the percentage fell to 31.1% (p = 0.0019). These results are suggestive of an association of SSTI acquired in the community with overcrowding and poverty. The presence of CaMRSA in community SSTIs should be suspected. Vancomycin or clindamycin prophylaxis could be considered when cesarean deliveries are performed in women from areas with high NBI or with a history of SSTI.

Relación entre hacinamiento e infecciones comunitarias de piel y partes blandas / Relationship between crowding and community acquired skin and soft tissues infections

La asociación entre diseminación de infecciones comunitarias, pobreza y hacinamiento es bien conocida. En nuestro hospital observamos casos esporádicos de infecciones post-cesárea por cepas de Staphylococcus aureus meticilino resistente de origen comunitario (SAMRCo). En un estudio prospectivo de familias de José C. Paz atendidas en nuestro hospital, investigamos la relación entre antecedentes de infecciones de piel y partes blandas (IPPB) y hacinamiento extremo (hogares con necesidades básicas insatisfechas tipo 3, (NBI 3). Fueron incluidos 264 hogares; 109 (41.3%) tenían historia de IPPB y 59 (22.3%) eran NBI 3. El 61.0% de los hogares NBI 3 y el 35.6% de los hogares no NBI 3 refirieron IPPB (p = 0.00047). Georreferenciamos los domicilios con Google Maps y los ubicamos en un plano de José C. Paz NBI del censo nacional 2010. En barrios con un porcentaje de NBI > 9.7%, el 51.2% de los hogares tuvo antecedentes de IPPB. Cuando este porcentaje era ≤ 9.7% el porcentaje bajó al 31.1% (p = 0.0019). Estos resultados son sugestivos de diseminación comunitaria de estas infecciones asociada a hacinamiento y barrios pobres. Se debe considerar la presencia de SAMRCo en IPPB comunitarias. Por ello, en mujeres procedentes de zonas con alto porcentaje NBI o con antecedentes de IPPB se podría considerar la inclusión de la vancomicina o la clindamicina en la profilaxis de los partos por cesárea.

The association of the spread of community infections with poverty and overcrowding is well known. In our hospital, located in José C. Paz, we assist sporadic cases of post-cesarean infections caused by community acquired methicillin-resistant Staphylococcus aureus (CaMRSA). In a prospective study of families treated at our hospital, we investigated the relationship between a history of skin and soft tissue infections (SSTI) and extreme overcrowding defined as households with unsatisfied basic needs type 3 (NBI 3). A total of 264 households were included in the study; 109 (41.3%) had a history of SSTI and 59 (22.3%) were NBI 3. A total of 61.0% of the NBI 3 households and 35.6% of the non-NBI 3 households reported SSTI (p = 0.00047). Using Google Maps, we georeferenced households and identified them on a NBI map adapted from the 2010 demographic census. In neighborhoods with NBI > 9.7%, 51.2% of the households had a history of SSTI. When NBI was < 9.7%, the percentage fell to 31.1% (p = 0.0019). These results are suggestive of an association of SSTI acquired in the community with overcrowding and poverty. The presence of CaMRSA in community SSTIs should be suspected. Vancomycin or clindamycin prophylaxis could be considered when cesarean deliveries are performed in women from areas with high NBI or with a history of SSTI.

Extensions to Bayesian generalized linear mixed effects models for household tuberculosis transmission.

Household contact studies, a mainstay of tuberculosis transmission research, often assume that tuberculosis-infected household contacts of an index case were infected within the household. However, strain genotyping has provided evidence against this assumption. Understanding the household versus community infection dynamic is essential for designing interventions. The misattribution of infection sources can also bias household transmission predictor estimates. We present a household-community transmission model that estimates the probability of community infection, that is, the probability that a household contact of an index case was actually infected from a source outside the home and simultaneously estimates transmission predictors. We show through simulation that our method accurately predicts the probability of community infection in several scenarios and that not accounting for community-acquired infection in household contact studies can bias risk factor estimates. Applying the model to data from Vitória, Brazil, produced household risk factor estimates similar to two other standard methods for age and sex. However, our model gave different estimates for sleeping proximity to index case and disease severity score. These results show that estimating both the probability of community infection and household transmission predictors is feasible and that standard tuberculosis transmission models likely underestimate the risk for two important transmission predictors. Copyright © 2017 John Wiley & Sons, Ltd.

[Methicillin-sensitive Staphylococcus aureus isolates related to USA300 clone: Origin of community-genotype MRSA in Colombia?]. / Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia?

INTRODUCTION: USA300 is a genetic lineage found both in methicillin-resistant (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) isolates. In Colombia, hospital and community MRSA infections are caused by a USA300-related community genotype MRSA (CG-MRSA) clone. The genetic origin of this clone is unknown yet. OBJECTIVE: To identify and characterize methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates in order to improve the information about the origin of the CG-MRSA isolates in Colombia. MATERIALS AND METHODS: USA300-related MSSA isolates were detected and characterized from a study of 184 S. aureus isolates (90 MRSA and 94 MSSA) recovered from infections. The genetic relatedness of the isolates was established by means of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and protein A gene typification ( spa typing). RESULTS: Among 184 isolates, 27 (14.7%) showed molecular characteristics and genetic relationship with the USA300 clone, of which 18 were MRSA and nine were MSSA. All USA300-related MRSA harbored Staphylococcal cassette chromosome mec (SCC mec ) IVc (3.1.2). In the MSSA isolates, SCC mec remnants or att B duplicate sites were not detected. CONCLUSIONS: In Colombia, the CG-MRSA isolates probably originated in the dissemination of an USA300-related MSSA clone which later acquired SCC mec IVc.

Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia? / Methicillin-sensitive Staphylococcus aureus isolates related to USA300 clone: Origin of community-genotype MRSA in Colombia?

Introducción. USA300 es un linaje genético que se encuentra en aislamientos de Staphylococcus aureus sensibles (SASM) y resistentes a meticilina (SARM). Actualmente, en Colombia las infecciones por SARM en hospitales y en la comunidad son causadas principalmente por un clon con genotipo comunitario (SARM-GC) relacionado genéticamente con el clon USA300. El origen de esta variante es aún desconocido. Objetivo. Identificar y caracterizar aislamientos de S. aureus resistentes y sensibles a meticilina con el fin de aportar información para establecer un posible origen de los aislamientos SARM-GC en Colombia. Materiales y métodos. Se realizó una caracterización de aislamientos SASM relacionados con el clon USA300 detectados a partir de un análisis de 184 aislamientos de S. aureus (90 SARM y 94 SASM) causantes de infecciones. La relación genética de los aislamientos se determinó por electroforesis en gel de campo pulsado (PFGE), tipificación de secuencias multilocus (MLST) y tipificación del gen de la proteína A ( spa ). Resultados. De los 184 aislamientos, 27 (14,7 %) presentaron características moleculares y relación genética con el clon USA300, y de ellos, 18 fueron SARM y nueve fueron SASM. Todos los aislamientos SARM relacionados con este clon albergaban un casete estafilocócico cromosómico mec (SCC mec ) IVc (3.1.2). En ningún aislamiento SASM se detectaron secuencias remanentes de SCC mec o una duplicación del sitio att B que evidenciaran la pérdida del casete. Conclusión. El origen de los aislamientos SARM-GC en Colombia probablemente se encuentre en la diseminación de clones SASM relacionados con el clon USA300 que adquirieron el SCC mec IVc posteriormente.

Introduction: USA300 is a genetic lineage found both in methicillin-resistant (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) isolates. In Colombia, hospital and community MRSA infections are caused by a USA300-related community genotype MRSA (CG-MRSA) clone. The genetic origin of this clone is unknown yet. Objective: To identify and characterize methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates in order to improve the information about the origin of the CG-MRSA isolates in Colombia. Materials and methods: USA300-related MSSA isolates were detected and characterized from a study of 184 S. aureus isolates (90 MRSA and 94 MSSA) recovered from infections. The genetic relatedness of the isolates was established by means of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and protein A gene typification ( spa typing). Results: Among 184 isolates, 27 (14.7%) showed molecular characteristics and genetic relationship with the USA300 clone, of which 18 were MRSA and nine were MSSA. All USA300-related MRSA harbored Staphylococcal cassette chromosome mec (SCC mec ) IVc (3.1.2). In the MSSA isolates, SCC mec remnants or att B duplicate sites were not detected. Conclusions: In Colombia, the CG-MRSA isolates probably originated in the dissemination of an USA300-related MSSA clone which later acquired SCC mec IVc.

Evidence of transmission of a Panton-Valentine leukocidin-positive community-acquired methicillin-resistant Staphylococcus aureus clone: a family affair.

Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) may represent a serious public health problem, owing to the spread of toxin-producing lineages. The presence of genes encoding for Panton-Valentine leukocidin (PVL) is an important virulence marker, as the clinical sequelae of PVL-positive infections are often described as more severe than those of PVL-negative S. aureus infections. To date, the presence of PVL has not appeared to be common in Italy; we describe the intrafamilial transmission of an epidemic PVL-producing CA-MRSA lineage, Southwest Pacific clone (SWP). Our data suggested that the strain circulated from the father, who was recurrently affected by a soft tissue infection, to the mother, who showed nasal colonization, and to their child, who was hospitalized with symptoms of necrotizing pneumonia. In this case, we found that a recurrent skin infection that is not normally taken into account may represent a serious threat if caused by a PVL-producing strain. Our findings may have considerable implications for strategies for infection control and treatment of methicillin-resistant S. aureus infections.

Nasal carriage of Panton Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus in healthy preschool children / Colonización nasal de Staphylococcus aureus Meticilino Resistente portador de la Leucocidina Panton-Valentine en preescolares

Objective Determining the prevalence of nasal carriage of S. aureus, both sensitive to methicillin and resistant to it, in preschool children and evaluating the presence of Panton-Valentine leukocidin genes in the isolates. Methods This was a cross-sectional study in which cultures from anterior nares were obtained from healthy preschool children. Isolates were identified as S. aureus based on morphological and biochemical tests. Antibiotic susceptibility profiles were determined by the disk diffusion method. All the isolates were further analyzed by multiplex PCR to determine the presence of mecA and PVL genes; methicillin-resistant isolates were also SCCmec typed by multiplex PCR. Results Overall S. aureus nasal colonization prevalence was 38.5 % and 4.8 % for methicillin-resistant strains. All the methicillin-resistant isolates carried the genes for PVL; two isolates possessed the SCCmec type IV, two were SCCmec type I and one was SCCmec type II. Conclusion This study revealed high PVL-positive, methicillin-resistant S. aureus colonization prevalence in healthy preschool children from Cartagena, which may play a key role in the epidemiology of community-associated infection by methicillin-resistant S. aureus in healthy children from this particular geographical area.

Objetivo Determinar la prevalencia de colonización nasal de S. aureus, tanto sensible como resistente a meticilina, en niños preescolares y evaluar la presencia de los genes de la leucocidina Panton-Valentine en estos aislamientos. Métodos Estudio de corte transversal en el que se realizaron cultivos de flora nasal de niños preescolares. Los aislamientos fueron identificados como S. aureus con base en su morfología y pruebas bioquímicas. La susceptibilidad a antibióticos se determinó por el método de difusión en disco. Todos los aislamientos fueron analizados por PCR múltiple para determinar la presencia de los genes mecA y PVL, y para la tipificación del casete cromosómico SCCmec de los aislamientos resistentes a meticilina. Resultados La colonización nasal por S. aureus fue 38,5 %, y la de cepas meticilino-resistentes fue 4,8 %. Todos los aislamientos SARM portaban los genes para PVL, dos portaban el elemento SCCmec tipo IV, dos fueron tipo I y uno fue tipo II. Conclusión Encontramos una alta prevalencia de colonización por cepas meticilino-resistentes, PVL-positivos en la población estudiada, lo que podría jugar un papel clave en la epidemiología de las infecciones por S.aureus meticilino-resistente en esta área geográfica.

Epidemiologic inference from the distribution of tuberculosis cases in households in Lima, Peru.

BACKGROUND: Tuberculosis (TB) often occurs among household contacts of people with active TB. It is unclear whether clustering of cases represents household transmission or shared household risk factors for TB. METHODS: We used cross-sectional data from 764 households in Lima, Peru, to estimate the relative contributions of household and community transmission, the average time between cases, and the immunity afforded by a previous TB infection. RESULTS: The distribution of cases per household suggests that almost 7 of 10 nonindex household cases were infected in the community rather than in the household. The average interval between household cases was 3.5 years. We observed a saturation effect in the number of cases per household and estimated that protective immunity conferred up to 35% reduction in the risk of disease. CONCLUSIONS: Cross-sectional household data can elucidate the natural history and transmission dynamics of TB. In this high-incidence setting, we found that the majority of cases were attributable to community transmission and that household contacts of case patients derive some immunity from household exposures. Screening of household contacts may be an effective method of detecting new TB cases if carried out over several years.

Nasal carriage of Panton Valentine leukocidin-positive methicillin-resistant Staphylococcus aureus in healthy preschool children.

OBJECTIVE: Determining the prevalence of nasal carriage of S. aureus, both sensitive to methicillin and resistant to it, in preschool children and evaluating the presence of Panton-Valentine leukocidin genes in the isolates. METHODS: This was a cross-sectional study in which cultures from anterior nares were obtained from healthy preschool children. Isolates were identified as S. aureus based on morphological and biochemical tests. Antibiotic susceptibility profiles were determined by the disk diffusion method. All the isolates were further analyzed by multiplex PCR to determine the presence of mecA and PVL genes; methicillin-resistant isolates were also SCCmec typed by multiplex PCR. RESULTS: Overall S. aureus nasal colonization prevalence was 38.5 % and 4.8 % for methicillin-resistant strains. All the methicillin-resistant isolates carried the genes for PVL; two isolates possessed the SCCmec type IV, two were SCCmec type I and one was SCCmec type II. CONCLUSION: This study revealed high PVL-positive, methicillin-resistant S. aureus colonization prevalence in healthy preschool children from Cartagena, which may play a key role in the epidemiology of community-associated infection by methicillin-resistant S. aureus in healthy children from this particular geographical area.

Emergence and dissemination of extended-spectrum beta-lactamase-producing Escherichia coli in the community: lessons from the study of a remote and controlled population.

BACKGROUND: Intestinal carriage is a key factor in extended-spectrum beta-lactamase (ESBL) infection epidemiology but is difficult to study in open communities. To overcome this problem, we studied a highly stable group of Amerindians for whom we reported an ESBL carriage prevalence of 3.2% in 2001. METHODS: In 2006, ESBL carriage was assessed among 163 healthy volunteer adults. ESBL isolates were identified, and their molecular resistance mechanisms were characterized. Antibiotic use in the year before sampling and the epidemiological characteristics of the population were analyzed. Results were compared to those obtained in 2001. RESULTS: In 2006, the ESBL carriage prevalence, exclusively comprising Escherichia coli, was 8.0%. It mainly consisted of CTX-M-type ESBL. The strains and plasmids carrying ESBL were heterogeneous, but 1 CTX-M-2-producing strain was found in 4.3% of the subjects analyzed. No individual risk factor was identified. However, overall antibiotic use had almost doubled since 2001. A 3-fold increase was noted for beta-lactams. CONCLUSIONS: In this population, the frequency of ESBL increased with time because of the appearance of CTX-M ESBL, mimicking what occurs in the developed world. This resulted from the probable repeated introduction of new strains and plasmids and from interindividual dissemination. During the same period, antibiotic use substantially increased.

Abordagem inicial das pneumonias comunitárias em pronto-socorro / Initial approach of community pneumonias in emergency care

A pneumonia é uma infecção que envolve os alvéolos e os bronquíolos, podendo ser causada por bactéria, vírus ou parasitas. Pneumonia adquirida na comunidade (PAC) é a que acomete o paciente fora do ambiente hospitalar ou em até 48 horas após admissão. A PAC é a segunda causa de internação no Brasil, estando a mesma associada a morbidade e mortalidade significativas e custo elevado.

Suburban transmission of Q fever in French Guiana: evidence of a wild reservoir.

The annual incidence of Q fever in French Guiana was found to have increased in 1996 and was 37/100,000 population over the last 4 years. Subsequent investigations in Cayenne and its suburbs indicated that a wild reservoir of the bacteria was responsible for the epidemiologic pattern. A case-control study showed that residence near a forest and occupations and activities that result in exposure to aerosols of dusts from the soil are risk factors for Q fever. By means of time-series analysis, a strong positive correlation between rainfall and the incidence of Q fever with a time lag of 1-3 months was found. The spatial distribution of the cases showed that transmission occurs widely throughout greater Cayenne, which is incompatible with a pinpoint source of contamination. Transmission from livestock and dissemination of the bacteria by the wind appeared to be unlikely, which strengthens the hypothesis that a wild reservoir is responsible for transmission.