María José Rial

Estudio multicéntrico sobre las infecciones pediátricas por Staphylococcus aureus meticilino-resistente provenientes de la comunidad en la Argentina

INTRODUCTION Methicillin-resistant Staphylococcus aureus (MRSA) isolates are increasingly frequent causes of skin and soft-tissue infections or invasive infections in many communities. Local data are scarce. OBJECTIVE To determine the frequency, clinical features and outcome of infections caused by MRSA. MATERIAL AND METHODS Prospective and multicentric study of surveillance for community-acquired S. aureus infections in children from Argentina. Infections meeting the definition of community-acquired were identified. Demographic and clinical data were collected. Antibiotic susceptibilities were determined in the clinical microbiology laboratory with the methodology of the NCCLS. RESULTS From November 2006 to November 2007, 840 S. aureus infections were diagnosed, 447 of them were community-acquired. One hundred and thirty-five children with underlying disease or previous hospital admission were excluded. Two hundred and eighty one (62%) infections were community-acquired MRSA (CA-MRSA). The median age of children was 36 months (r:1-201), 60% were male. Among the CA-MRSA isolates, 62% were obtained from children with skin and soft-tissue infections, and 38% from children with invasive infections. Of them, osteomyelitis, arthritis, empyema and pneumonia were prevalent. Eigthteen percent of children had bacteremia and 11% sepsis. The rate of clindamycin resistance of CA-MRSA isolates was 10% and 1% for trimethoprim-sulfamethoxazole. Only 31% of children had appropriate treatment at admission. The median time of treatment delayed was 72 h. The median time of parenteral treatment was 6 days (r:1-70). In 72% of patients surgical treatment was required. Three children died (1%). CONCLUSIONS CA-MRSA isolates account for a high percentage and number of infections in children of Argentina. Community surveillance of CA-MRSA infections is critical to determine the appropriate empiric antibiotic treatment for either local or invasive infections. Clindamycin resistance was under 15% in the strains tested. Clindamycin should be use when CA-MRSA infection is suspected in children.

Study to determine the ability of clinical laboratories to detect antimicrobial-resistant enterococcus spp. in Buenos Aires, Argentina

Few reports of vancomycin-resistant enterococci have appeared outside the USA. Therefore, we evaluated the ability of five laboratories in Buenos Aires, Argentina, to perform susceptibility testing using the disk diffusion method. Laboratories had difficulty identifying the low- and intermediate-level vancomycin-resistant phenotypes. This suggests that the disk diffusion method used by laboratories abroad may fail to detect some vancomycin-resistant enterococci.

Infecciones invasivas por Streptococcus pneumoniae: Estudio epidemiológico e importancia del desarrollo de un sistema de vigilancia

Las infecciones invasivas por streptococcus pnneumoniae(Spn)producen mortalidad elevada en paises en desarrollo,con tasa entre 4 y 100 veces mayores que las de Estados Unidos o Canada.Es el primer agente causal de neumonia en la infancia y de meningitis fuera de los brotes epidemicos po neisseria meningiditis.La OPS,a traves del grupo SIREVA,dedicado al desarrollo de vacunas en Latinoamerica,organizo un programa de vigilancia de infecciones invasivas por Spn en seis paises:argentina,Brasil,chile,colombia,Mexico y Uruguay iniciado en 1993 y que continua actualmente.En Argentina participan en la actualidad mas de 20 centros hospitalarios distribuidos en todas la areas geograficas del pais,actuando como Centro Nacional de referencia para la serotipificacion y determinacion de la resistencia a los antibioticos el Instituto ANLIS uDr.Carlos G Malbran.Objetivos.1)determinar los serotipos predominates,su resistencia a los antibioticos y los cambios temporales en infecciones invasivas por Spn de ninos menores de 5 anos de edad.2)Obtener informacion confiable para la formulacion de una vacuna conjugada adecuada para la region.Conclusiones.Un programa nacional de vigilancia de Spn invasivo fue desarrollado en Argentina y otros paises Latinoamericanos.Se identificaron por primera vez los serotipos predominantes en infecciones invasivas y se comprobo el incremento significativo de la resistencia a penicilina y otros antibioticos,similar a lo informado en casi todos los paises del mundo.Se obtuvo informacion epidemiologica valida para evaluar estrategias de prevencion en nuevas vacunas

Seasonality of respiratory syncytial virus in Buenos Aires. Relationship with global climate change.

INTRODUCTION Global climate change circulation pattern respiratory syncytial virus (RSV). We assessed whether RSV season has changed over the past 20 years and its correlation with mean annual temperature. METHODS Cross-sectional study that included records of RSV and temperatures from Buenos Aires (1995-2014). RSV season onset, offset and duration, and its correlation with mean annual temperature were described for each year. RESULTS A total of 8109 RSV infections were identified. The duration of RSV season reduced significantly (1995: 29 weeks vs. 2014: 17 weeks; R: 0.6; p < 0.001) due to an early ending (1995: week 45 vs. 2014: week 33; R: 0.6; p < 0.001). No correlation was observed between mean annual temperature and RSV season start, end and duration. CONCLUSIONS Over the past 20 years, RSV season shortened significantly, but no correlation with temperature was observed.

Validation of a simplified prediction rule to identify etiology in children with pneumonia

INTRODUCTION Identifying on admission those children with bacterial pneumonia could reduce inappropriate antibiotic use. The BPS (Bacterial Pneumonia Score) is a clinical prediction rule that accurately identifies children with bacterial pneumonia. Because the interpretation of chest X-ray included in this model could be considered difficult, a simplified version was developed, but this version has not yet been validated in a different population. OBJECTIVE To validate a simplified clinical prediction rule to identify children with an increased risk of having bacterial pneumonia. METHODS Children aged under 5 years, hospitalized for pneumonia (viral or bacterial) were included. On admission, axillary temperature, age, absolute neutrophil count, bands, and chest radiograph were evaluated. RESULTS We included 168 patients (23 with bacterial pneumonia and 145 with viral pneumonia). Those with bacterial pneumonia showed a score higher than those with viral pneumonia (5.3 ± 2.5 vs. 2.6 ± 2.02; p <0.001). A score =3 points was identified as the optimum cutoff value to predict bacterial pneumonia (aucROC= 0.79; 95% IC: 0.68-0.90), and was more frequent among patients with bacterial than viral pneumonia (19/23 vs. 42/145, p= 0.003; OR: 4.8; CI95%: 1.4-17.6), achieving 82.6% sensitivity, 50.3% specificity, 20.9% positive predictive value, 94.8% negative predictive value, 1.66 positive likelihood ratio and 0.35 negative likelihood ratio. CONCLUSIONS The evaluated simplified prediction rule showed a limited diagnostic accuracy on identifying children with bacterial pneumonia, being less accurate than the BPS.

Habilidad de la radiografía de tórax para predecir etiología en niños hospitalizados con neumonía

ABSTRACT Chest X-ray capacity to predict the etiology of pneumonia in hospitalized children Introduction: Distinguishing bacterial from viral pneumonia on admission to the hospital could guide thedecision of whether or not to use antibiotics. Objective: To evaluate the accuracy of chest radiograph topredict etiology (bacterial or viral) in 141 children aged under 10 years, hospitalized for pneumonia in whombacterial (n = 24) or viral (n = 117) etiology was identified. Methods: Chest radiograph evaluation was basedon Khamapirad score (-3 to 7 points), and blinded with regard to etiology. Results: Radiographic score washigher in bacterial pneumonias than in viral pneumonias (3.9 ± 0.92 vs – 1.6 ± 1.3 points; p < 0.0001).Optimum cut-off value for the score was identified (ROC curve) at ≥ 2 points (sensitivity: 100%; specificity:94 %; positive predictive value: 77%; negative predictive value: 100%). Conclusion: The score tested isbased on easily identifiable elements in the chest radiograph. It accurately identifies children who do notneed antibiotics, it could be helpful in the management of community acquired pneumonia.(Key words: Bacterial pneumonia, Viral pneumonia, Radiology).Arch.argent.pediatr 2006; 104 (2): 106-108RESUMENIntroduccion: Conocer la etiologia de las neumonias puede guiar la decision de usar o no antibioticos. Laradiologia puede colaborar en esa decision. Nuestro objetivo fue evaluar la capacidad de la radiografia detorax para predecir la etiologia (bacteriana o viral). Poblacion: Cientocuarenta y un ninos menores de 10anos hospitalizados por neumonia con diagnostico etiologico confirmado (viral = 117 y bacteriano = 24).Material y Metodos: La radiografia de torax fue evaluo a ciegas con respecto a otros datos mediantepuntaje de Khamapirad (de – 3 a 7 puntos). Resultados: El puntaje radiologico fue significativamentemayor en neumonias bacterianas que en virales (3,9 ± 0,92 vs – 1,6 ± 1,3 puntos; p < 0,0001). Se identifico a≥ 2 puntos (curva ROC) como el mejor nivel para identificar neumonias bacterianas (sensibilidad: 100%;CONO SURSOUTH CONE OF AMERICA