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The urinary tract infection (UTI) is one of the most common bacterial infections in childhood. An adequate diagnosis is essential to be able to carry out a rational, efficient and effective treatment, however, there is great heterogeneity in diagnostic methods, specifically in the study of antimicrobial susceptibility. The aim of these recommendations is to provide tools to homogenize the diagnosis criteria, susceptibility study and antimicrobial treatment of urinary tract infection in the pediatric population, with a rational use of antibiotics approach. In the first part, the recommendations regarding diagnosis were presented, such as sampling and cut-off points, as well as microbiological considerations for susceptibility study and management of UTI in pediatrics. This second part details the management of complications, UTI in special situations, and pharmacokinetic and pharmacodynamic considerations of antimicrobials to be prescribed in UTI.

The urinary tract infection (UTI) is one of the most common bacterial infections in childhood. An adequate diagnosis is essential to be able to carry out a rational, efficient and effective treatment, however, there great heterogeneity in diagnostic methods, specifically in the study of antimicrobial susceptibility. The aim of these recommendations is to provide tools to homogenize the diagnosis criteria, susceptibility study and antimicrobial treatment of urinary tract infection in the pediatric population, with a rational use of antibiotics approach. In the first part, the recommendations regarding diagnosis are presented, such as sampling and cut-off points, as well as microbiological considerations for susceptibility study and management of UTI in pediatrics. The second part details the management of complications, UTI in special situations, and pharmacokinetic and pharmacodynamic considerations of antimicrobials to be prescribed in UTI.

El progreso socio-economico de la poblacion chilena se ha traducido tambien en la evolucion epidemiologica de las neumonias en pediatria. De ser una primordial causa de mortalidad, junto con la diarrea aguda, hoy, la neumonia continua siendo una importante causa de hospitalizacion, pero su letalidad se ha reducido considerablemente. Factores determinantes en este progreso han sido: mejores condiciones nutricionales de los pacientes, mejor y pronto acceso a la salud, optimizacion de los servicios de urgencia perifericos y aquellos adosados a los hospitales con servicios pediatricos, avances en los cuidados intensivos de pacientes criticos e, indudablemente, cambios etiologicos, a saber, bacterias por virus como primerisima etiologia de las IRAS bajas. Este ultimo componente- la evolucion etiologica de la neumonia adquirida en la comunidad por ninos-es abordado en esta guia, cuyo objeto es racionalizar el uso prudente y adecuado de antimicrobianos en la neumonia de causa bacteriana en Pediatria Esta guia excluye aquellas neumonias que afectan a pacientes con afecciones cronicas (que mantienen contacto estrecho con recintos hospitalarios y/o con internaciones periodicas), pacientes inmunocomprometidos y lactantes bajo 3 meses de edad. Diversos factores (ambientales, comorbilidades, inmunitarios, etc.), nos llevan a no incluir a estos pacientes en una recomendacion general.

La otitis media aguda (OMA), una de las infecciones mas comunes de la infancia, es la causa mas frecuente de visitas al medico, de consumo de antimicrobianos y de indicacion quirurgica en ninos. En los ultimos anos se han realizado grandes esfuerzos en la prevencion de la OMA, como la implementacion de vacuna conjugada de Streptococcus pneumoniae, el fomento de prolongar la lactancia materna y las campanas para disminuir el consumo de tabaco, factores que han tenido impacto en su epidemiologia, con reduccion en la incidencia y cambios en su perfil microbiologico. El diagnostico es basicamente clinico y, dado los cambios epidemiologicos antes descritos, se hace de vital importancia su correcto reconocimiento y el uso adecuado de antimicrobianos.

La coqueluche puede ser letal en neonatos y lactantes en sus primeros meses de vida. En estas edades, la vacunación anti Bordetella pertussis no ha sido administrada aún o completada hasta lograr la protección del niño. La estrategia de capullo implementada en diversas naciones es de limitada eficacia por la dificultad que entraña alcanzar altas coberturas entre los contactos de los neonatos. Surge como una posibilidad la vacunación en la mujer embarazada, estrategia fundamentada en el efectivo paso de anticuerpos maternos al neonato a partir de las 32-34 semanas de gestación. El Reino Unido, los Estados Unidos de América y luego otros países en Europa y América, han adoptado esta estrategia de vacunación. Publicaciones recientes provenientes del Reino Unido, sobre la seguridad y efectividad de la vacunación en la mujer embarazada, para evitar casos fatales de coqueluche, apoyan estas decisiones adoptadas pese a no disponerse de estudios controlados en el binomio madre-hijo. Múltiples estudios finalizados pero no publicados o aún en desarrollo, pretenden responder estas dos preguntas y evaluar además si los anticuerpos que atraviesan la placenta interfieren sobre las vacunas que serán administradas al lactante en los primeros meses de vida. Recientemente, la Organización Mundial de la Salud ha recomendado considerar la vacunación durante el embarazo en países donde la coqueluche es un importante problema de salud pública en neonatos. Se discute en Chile si es la vacunación anti-pertussis en la mujer gestante una estrategia a adoptar.

Invasive pneumococcal disease (IPD) remains as an important cause of morbidity in the world and in our country, while in Chile the incidence has decreased after the incorporation of the 10 valent pneumococcal conjugate vaccine, in the routine infant inmunization schedule (EPI). One of the expected effects of the program after vaccination with 10-valent pneumococcal vaccine is the likely replacement serotype phenomenon that means the presence of ENI caused by serotypes not included in the vaccine. In this context, we present the case of a child with pneumococcal meningitis caused by serotype 19 A of fatal course. The occurrence of ENI in a later stage of pneumococcal vaccine incorporation in Chile reinforces the importance of active surveillance, in order to know in detail the impact of vaccination, distribution of circulating serotypes and their correlation with the different clinical disease and their severity.

Introduction Clostridium difficile is the most commonly isolated organism in antimicrobial and health care-associated diarrhea and is growing in relevance in community-acquired infections. It is a Gram-positive bacillus acquired via the fecal-oral route in the community and in hospital setting. Epidemiology 0.6 to 2.1% worldwide incidence, mortality ~ 1-5%. COLONIZATION: High rates of asymptomatic colonization in healthy people, 37% in children: its presence in stools is of controversial significance. Risk factors in children are prior exposure to antibiotics, recent hospitalization, immunosuppression or inflammatory bowel disease. Clinical manifestations Secondary to intestinal involvement due to toxin production, ranging from asymptomatic colonization to fulminant disease. Diagnosis Clinical diagnostic criteria plus high sensitivity and specificity laboratory certification. Recommendations AAP (American Academy of Pediatrics): under 1 year, avoid routine study, only in Hirschsprung disease and/or nosocomial outbreak, 1-3 year, a (+) result suggests C. difficile associated diarrhea (CDAD) is possible, and in children older than 3 years interpretation is equal to adults. Management Antimicrobial suspension, oral metronidazole as first line in mild to moderate CDAD, and oral or enema vancomycin or associated with intravenous metronidazole only in severe cases. Duration 10 days. Prevention Antimicrobial control programs and environmental management. Conclusion Given the increasing complexity of pediatric patients it is important to deepen the knowledge on this microorganism and its clinical manifestations, as its incidence, morbidity and mortality are increasing.

El resurgimiento de la coqueluche en el mundo y en nuestro país ha puesto en tela de juicio la eficacia de las vacunas celulares y acelulares. Las razones de por qué la coqueluche no es controlada ni eliminada después de 70 años de implementación de la vacunación son diversas y probablemente multifactoriales. En este artículo, en base a preguntas y respuestas, se describen las bondades y limitaciones de tanto vacunas celulares como acelulares y queda sugerida una mejor forma de administrar ambas en la infancia. Es un hecho que la vacunación actualmente aplicada no elimina la circulación de Bordetella pertussis en la comunidad. Tal vez la introducción de vacunas con B. pertussis viva, inhalatoria, sea capaz de eliminar la enfermedad de la humanidad.

El bazo tiene la capacidad intrínseca de prevenir infecciones bacterianas invasoras dado su habilidad de filtrar y fagocitar las bacterias de la sangre, retirar partículas o elementos ajenos a ella y la producción precoz de opsoninas. La ausencia anatómica del bazo generalmente es secundaria a su remoción quirúrgica y también puede ser congénita. Streptococcus pneumoniae es el principal agente responsable de los episodios de infecciones bacterianas fulminantes y conlleva a una alta mortalidad en este grupo de pacientes. Se presenta una exhaustiva revisión de la evidencia y recomendaciones actualmente disponibles en la literatura para la prevención de infecciones invasoras en este grupo específico de pacientes.

La encefalitis herpética genera un desafío diagnóstico y es causa de alta morbi-mortalidad en niños. Se requiere de una sospecha clínica precoz y una prueba diagnóstica útil, rápida y segura, ya que sin tratamiento oportuno y adecuado, hasta 70% de los casos puede fallecer. Comunicamos el caso de una recién nacida de 25 días de vida, que presenta un cuadro clínico compatible con encefalitis herpética, donde el diagnóstico etiológico tardó en ser confirmado y sólo la técnica de reacción de la polimerasa en cadena en tiempo real (RPC-TR) aplicada de forma repetida permitió certificar la presencia de virus herpes simplex tipo 1 en el LCR.

Accurate diagnosis of catheter-related blood stream infection (CRBSI) is necessary to make a decision about removal of the catheter. Differential time to positivity (DTP) and the ratio of quantitative cultures (RQC) between central and peripheral blood cultures have not been evaluated against a strict standard in children, namely catheter tip culture.Our aim is to compare DTP and RQC in the diagnosis of catheter tip-confirmed catheter-related infection in children.Prospective study performed in 2 large hospitals in Santiago, Chile. Children with clinically suspected CRBSI had 2 peripheral and central vein blood samples obtained for automated culture in Bact/Alert and for quantitative cultures in 5% sheep blood agar plate. The catheter tip was cultured. Sensitivity, specificity, positive predictive value, negative predictive value, likelihood ratios (LR), and accuracy of DTP and RQC were compared against catheter tip-confirmed CRBSI.During a 3-year period, 344 clinically suspected CRBSIs were diagnosed in children of which 124 episodes met study criteria. Catheter tip culture-confirmed CRBSI in 25 (20%) of 124 episodes. A total of 34 microorganisms were cultured from 25 CRBSI; 8 of 25 (32%) episodes were polymicrobial. Staphylococcus aureus followed by coagulase-negative Staphylococcus were the most common microorganisms. For CRBSI, DTP and RQC reached a sensitivity of 75% versus 24% (P0.001), specificity of 86 versus 94%, positive predictive value of 58% versus 50%, negative predictive value of 93% versus 82%, LR of 5.48 versus 4.50, and accuracy of 0.84 versus 0.79.In children, DTP was better than RQC for diagnosis of catheter tip-confirmed CRBSI.

Introducción: Los pacientes pediátricos con infección por VIH tienen un riesgo 100 veces mayor de presentar cáncer que los niños no infectados. Objetivos: Describir en niños chilenos con infección por VIH, los tipos de cáncer, su aparición en relación a las etapas de la enfermedad por VIH y la letalidad. Material y Métodos: Se creó un protocolo para conocer algunas características de estos pacientes desde el punto de vista de su infección por VIH y su patología oncológica. Resultados: De 360 niños infectados confirmados por el Instituto de Salud Pública a mayo de 2014, se diagnosticaron nueve casos con patología oncológica (2,5%).Todos los niños estaban con TARV, tenían una evolución de infección por VIH mayor a 3 años, en etapas clínicas/inmunológicas moderada a grave. Linfoma fue el cáncer más frecuente. Cinco niños, recibieron terapia de acuerdo al Programa Infantil Nacional de Drogas Antineoplásicas (PINDA). No hubo interacción entre tratamiento anti-neoplásico y terapia anti-retroviral. La mortalidad fue de 13,8 x 1.000 (5 casos). Conclusiones: La incidencia y tipo de neoplasias está de acuerdo con lo comunicado en la literatura científica internacional, con sobrevida inferior a los niños con infección por VIH sin neoplasias. La aparición de cáncer se observó en niños con larga evolución y compromiso clínico e inmunológico moderado a grave.

Pertussis may cause death in neonates and very young infants. In these ages pertussis vaccine has not been administered yet or infants haven't received enough doses of vaccine to protect them. Cocoon strategy have been implemented in several countries and has limited efficacy because of low coverage among households. In vaccinated pregnant women transplacental transfer of pertussis antibodies starts at 32-34 weeks of pregnancy. United Kingdom, The United States of America and afterward other countries in Europe and America have adopted this strategy. Recent British research about security and effectiveness of pertussis vaccination in pregnant women to reduce pertussis incidence and fatality cases in neonate and very young infants infant support this strategy despite the fact that controlled studies about the efficacy and security in mothers and neonates have not been published. Several studies still not published or in progress are trying to answer these two questions and to evaluate possible interference between transplacentaly transferred pertussis antibodies and infants immune response to routine vaccines. Recently WHO has recommended pertussis vaccination during pregnancy in countries where neonatal pertussis is a public health problem. Nowadays, Chilean experts discuss if pertussis vaccination of pregnant women must be adopted in our country.

Clostridium difficile is the most commonly isolated organism in antimicrobial and health care-associated diarrhea and is growing in relevance in community-acquired infections. It is a Gram-positive bacillus acquired via the fecal-oral route in the community and in hospital setting.0.6 to 2.1% worldwide incidence, mortality ~ 1-5%. COLONIZATION: High rates of asymptomatic colonization in healthy people, 37% in children: its presence in stools is of controversial significance. Risk factors in children are prior exposure to antibiotics, recent hospitalization, immunosuppression or inflammatory bowel disease.Secondary to intestinal involvement due to toxin production, ranging from asymptomatic colonization to fulminant disease.Clinical diagnostic criteria plus high sensitivity and specificity laboratory certification. Recommendations AAP (American Academy of Pediatrics): under 1 year, avoid routine study, only in Hirschsprung disease and/or nosocomial outbreak, 1-3 year, a (+) result suggests C. difficile associated diarrhea (CDAD) is possible, and in children older than 3 years interpretation is equal to adults.Antimicrobial suspension, oral metronidazole as first line in mild to moderate CDAD, and oral or enema vancomycin or associated with intravenous metronidazole only in severe cases. Duration 10 days.Antimicrobial control programs and environmental management.Given the increasing complexity of pediatric patients it is important to deepen the knowledge on this microorganism and its clinical manifestations, as its incidence, morbidity and mortality are increasing.

The resurgence of pertussis in the world and in our country has questioned the effectiveness of cellular and acellular vaccines. The reason why pertussis has not been controlled or eliminated after 70 years of implementation of the vaccination is probably multifactorial. This article, on the basis of questions and answers, describes the benefits and limitations of both cellular and acellular vaccines and suggests new strategies of vaccination in childhood. It is a fact that the currently applied vaccination does not eliminate the circulation of Bordetella pertussis in the community. Perhaps the introduction of vaccines with live B. pertussis, inhalation, will be able to eliminate the disease around the world.

Invasive pneumococcal disease (IPD) remains as an important cause of morbidity in the world and in our country, while in Chile the incidence has decreased after the incorporation of the 10 valent pneumococcal conjugate vaccine, in the routine infant inmunization schedule (EPI). One of the expected effects of the program after vaccination with 10-valent pneumococcal vaccine is the likely replacement serotype phenomenon that means the presence of ENI caused by serotypes not included in the vaccine. In this context, we present the case of a child with pneumococcal meningitis caused by serotype 19 A of fatal course. The occurrence of ENI in a later stage of pneumococcal vaccine incorporation in Chile reinforces the importance of active surveillance, in order to know in detail the impact of vaccination, distribution of circulating serotypes and their correlation with the different clinical disease and their severity.

UNLABELLED Tuberculosis (TB) remains a major health problem in the world. The clinical forms of TB in children are variable, pulmonary involvement occurs in two thirds of cases. In the remaining third, clinical forms incluye node, meningeal and osteoarticular involvement. CASE REPORT 7 year old boy with a history of an osteolytic lesion of the right ischial branch. Three months later he presented with spondylodiscitis at L2-L3, associated with a large abscess in the right iliac psoas muscle. Pott's disease was suspected, and tuberculin test and T-SPOT®.TB test were performed, with a positive result. Antimicrobial treatment was initiated with isoniazid, rifampicin, pyrazinamide and ethambutol. After 30 days, Mycobacterium tuberculosis was isolated from psoas abscess. We discuss methods of TB diagnosis, with special emphasis on immunological methods: tuberculin test and interferon-gamma release assays. Methods of immunological TB diagnosis are an important contribution to the diagnosis of this disease, allowing early initiation of treatment.

Objectives: We evaluated the in vitro antibacterial activity of amoxicillin against penicillin-susceptible and -nonsusceptible Streptococcus pneumoniae strains isolated from children with acute otitis media (AOM). Methods: Children more than 3 months of age with AOM who were seen in the Dr Sótero del Rio and Luis Calvo Mackenna Hospitals in Santiago, Chile, between July 1998 and December 2002 were subjected to tympanic puncture for middle ear fluid culture. The penicillin and amoxicillin susceptibilities of the S pneumoniae isolates were determined by epsilometer test (E test). Results: A bacterial pathogen was isolated in 432 of 543 children (80%) as follows: S pneumoniae, 40%; Haemophilus influenzae, 29%; Moraxella catarrhalis, 7%; and Streptococcus pyogenes, 4%. Penicillin-susceptible S pneumoniae strains were less common than amoxicillin-susceptible strains (60% versus 95%; odds ratio [OR], 0.08; 95% confidence interval [CI], 0.04 to 0.18). Both intermediate- and high-resistance strains were more common for penicillin (22% versus 4.5%; OR, 5.6; 95% CI, 2.5 to 12.7) than for amoxicillin (18% versus 0.5%; OR, 41.3; 95% CI, 6.0 to 821). Conclusions: Penicillin resistance is not extrapolable to amoxicillin among S pneumoniae strains isolated from middle ear fluid of children with AOM. Our results support the recommendation to evaluate the minimal inhibitory concentrations of penicillin-nonsusceptible S pneumoniae for amoxicillin and to continue use of this antimicrobial as a first-line antimicrobial choice for children with AOM.

Purpose To compare outcome and cost of ambulatory versus hospitalized management among febrile neutropenic children at low risk for invasive bacterial infection (IBI). Patients and Methods Children presenting with febrile neutropenia at six hospitals in Santiago, Chile, were categorized as high or low risk for IBI. Low-risk children were randomly assigned after 24 to 36 hours of hospitalization to receive ambulatory or hospitalized treatment and monitored until episode resolution. Outcome and cost were determined for each episode and compared between both groups using predefined definitions and questionnaires. Results A total of 161 (41%) of 390 febrile neutropenic episodes evaluated from June 2000 to February 2003 were classified as low risk, of which 149 were randomly assigned to ambulatory (n = 78) or hospital-based (n = 71) treatment. In both groups, mean age (ambulatory management, 55 months; hospital-based management, 66 months), sex, and type of cancer were similar. Outcome was favorable in 74 (95%) of 78 ambulatory-treated children and 67 (94%) of 71 hospital-treated children (P = NS). Mean cost of an episode was US $638 (95% CI, $572 to $703) and US $903 (95% CI, $781 to $1,025) for the ambulatory and hospital-based groups, respectively (P = .003). Conclusion For children with febrile neutropenia at low risk for IBI, ambulatory management is safe and significantly cost saving compared with standard hospitalized therapy.

Pediatric HIV (+) patients have a 100 times greater risk of cancer than HIV (-) children.To describe in Chilean HIV (+) children, cancer types, its appearance in relation to the stages of HIV disease and mortality.A protocol was created to know some characteristics of these patients from the point of view of their HIV infection and cancer pathology.Of 360 HIV (+) children confirmed by the Institute of Public Health to May 2014, 9 patients with neoplastic disease (2.5%) were diagnosed. All the children were on ART, had more than three years of evolution of HIV infection and were in moderate to severe clinical/immunological stages. Lymphoma was the most common cancer. Five children, has received therapy according to Programa Infantil Nacional de Drogas Antineoplásicas (PINDA). There was no interaction between cancer treatment and antiretroviral therapy. Mortality was 13.8 x 1000 (5 cases).The incidence and type of neoplasia is consistent with the international literature, with less survival than HIV (+) children without tumors. The occurrence of cancer was observed in children with moderate to severe clinical and immunological compromise.

Tuberculosis (TB) remains a major health problem in the world. The clinical forms of TB in children are variable, pulmonary involvement occurs in two thirds of cases. In the remaining third, clinical forms incluye node, meningeal and osteoarticular involvement.7 year old boy with a history of an osteolytic lesion of the right ischial branch. Three months later he presented with spondylodiscitis at L2-L3, associated with a large abscess in the right iliac psoas muscle. Pott's disease was suspected, and tuberculin test and T-SPOT®.TB test were performed, with a positive result. Antimicrobial treatment was initiated with isoniazid, rifampicin, pyrazinamide and ethambutol. After 30 days, Mycobacterium tuberculosis was isolated from psoas abscess. We discuss methods of TB diagnosis, with special emphasis on immunological methods: tuberculin test and interferon-gamma release assays. Methods of immunological TB diagnosis are an important contribution to the diagnosis of this disease, allowing early initiation of treatment.

PURPOSE: To identify clinical and laboratory parameters present at the time of a first evaluation that could help predict which children with cancer, fever, and neutropenia were at high risk or low risk for an invasive bacterial infection. PATIENTS AND METHODS: Over a 17-month period, all children with cancer, fever, and neutropenia admitted to five hospitals in Santiago, Chile, were enrolled onto a prospective protocol. Associations between admission parameters and risk for invasive bacterial infection were assessed by univariate and logistic regression analyses. RESULTS: A total of 447 febrile neutropenic episodes occurred in 257 children. Five parameters were statistically independent risk factors for an invasive bacterial infection. Ranked by order of significance, they were as follows: C-reactive protein levels of 90 mg/L or higher (relative risk [RR], 4.2; 95% confidence interval [CI], 3.6 to 4.8); presence of hypotension (RR, 2.7; 95% CI, 2.3 to 3.2); relapse of leukemia as cancer type (RR, 1.8, 95% CI, 1.7 to 2.3); platelet count less than or equal to 50,000/mm3 (RR, 1.7; 95% CI, 1.4 to 2.2); and recent (≤ 7 days) chemotherapy (RR, 1.3; 95% CI, 1.1 to 1.6). Other previously postulated risk factors (magnitude of fever, monocyte count) were not independent risk factors in this study population. CONCLUSION: In a large population of children, common clinical and laboratory admission parameters were identified that can help predict the risk for an invasive bacterial infection. These results encourage the possibility of a more selective management strategy for these children.

During a 2-year period, all children with cancer, neutropenia, and fever who were admitted to Hospital de Ninos Luis Calvo Mackenna (Santiago, Chile) were enrolled in a study of the safety of stopping antibiotic therapy on day 3 of treatment. Children who met predefined criteria for nonbacterial fever were randomized on day 3 to stop (group A) or continue (group B) antibiotic therapy. A total of 220 children with cancer had 238 episodes of fever and neutropenia; 68 children with 75 episodes met entry criteria for nonbacterial fever (group A, 36; group B, 39). Both groups were comparable in terms of age, gender, oncological disease, chemotherapy status, and initial neutrophil count. Resolution of symptoms occurred in 34 of 36 episodes in group A and 36 of 39 episodes in group B (P > .05). No deaths occurred, and bacterial superinfections were uncommon. For children with cancer as well as episodes of fever and neutropenia without an identifiable bacterial etiology at admission, stopping antibiotic therapy on day 3 was safe and not associated with a higher risk of bacterial superinfections.

The spleen's ability to prevent overwhelming post-splenectomy infection (OPSI) is mainly given by its capacity to filter and phagocyte bacterial elements from the blood, remove foreign elements from it, and the early production of opsonins. The anatomic absence of the spleen is usually secondary to a surgical resection, but it could also be congenital. Streptococcus pneumoniae has been identified as the main agent of OPSI in asplenic patients with an extremely high global mortality associated. This article is an exhaustive review of the current evidence and recommendations available for prevention of invasive infections in asplenic patients.

On account of an increase of serogroup W135 meningococcal disease (M.D.) observed in Santiago, Chile, during last two years the medical community has experienced an avidity to update their knowledge about M.D. treatment and its prevention. In a queries and answers mode, the following topics on M.D. are presented: nasopharyngeal carriage and its importance, immunity and protection against the disease, reasons to choice ceftriaxone as the first line antibiotic in treatment, rationality and indications of chemoprophylaxis, fundamentals and advantages of conjugate vaccines, its indications, schedules, contraindications and decisions making in public health.

A raíz de un alza en la frecuencia de casos de enfermedad meningocóccica (E.M.) del grupo W135 en la ciudad de Santiago, Chile, observada durante 2011 y 2012, se ha producido una avidez en la comunidad médica por actualizar su información acerca de los recursos recomendados para combatirla y prevenirla. En una modalidad de preguntas y respuestas, se abordan los siguientes tópicos en enfermedad meningocóccica: portación nasofaríngea y su trascendencia, inmunidad y protección contra la enfermedad, razones para preferir ceftriaxona en el tratamiento de la afección, racionalidad e indicaciones de la quimioprofilaxis, fundamentos y ventajas de las vacunas conjugadas, indicaciones, esquemas, contraindicaciones y toma de decisiones en salud pública.

The usefulness of determining serum levels of C-reactive protein (CRP) for the identification of bacterial infections in febrile neutropenic patients with cancer was evaluated. Two hundred children with cancer were monitored prospectively for the occurrence of neutropenia and fever; serum was collected from these children for determining baseline levels of CRP. Of these 200 children, 75 had 85 febrile neutropenic episodes; serum was collected daily from these 75 children for CRP analysis by nephelometry. Children were included into one of the three following groups by physicians blinded to results of CRP analysis: group I, demonstrated bacterial infection (24 episodes); group II, probable bacterial infection (31 episodes); and group III, viral infection or no infection (30 episodes). Baseline CRP values were low (mean, 9 mg/L; range, 0-35 mg/L) irrespective of tumor type or stage of therapy. Mean CRP values on day 1 for children in groups I and II (194 and 143 mg/L, respectively) were higher than those for children in group III (29 mg/L) (P.001). A CRP value of40 mg/L discriminated children with a demonstrated bacterial infection (sensitivity, 100%; specificity, 76.6%). Children with an unfavorable outcome had persistently high levels of serum CRP. For children with cancer, neutropenia, and fever, determination of the serum CRP level is useful for early diagnosis of bacterial infections and for monitoring the course of infection.

Herpes simplex encephalitis is a diagnostic challenge and causes high morbidity and mortality in children. Early suspicion of the disease and a rapid, safe and useful diagnostic test are relevant because up to 70% of the cases may die. We report the case of a newborn girl aged 25 days, who presented with a clinical picture that was compatible with herpes simplex encephalitis where the confirmation of the etiological diagnosis was delayed. Only by repeated real-time polymerase chain reaction it was possible to confirm the presence of herpes simplex virus type 1 in the cerebrospinal fluid.

Dealing with varicella often causes doubts to general practitioners and pediatricians. In this article the author summaries guidelines based on solid evidence to treat varicella and prevent the disease in susceptible contacts in different clinical scenarios and presents his personal point of view in those controversial aspects commonly resolved by the authorized opinion of experts.

El manejo de la varicela despierta, con alta frecuencia, dudas en los médicos generales y pediatras. En este artículo, el autor resume aquellas recomendaciones basadas en sólida evidencia, para tratar la varicela y prevenir la enfermedad en los contactos susceptibles de un caso índice, en diferentes situaciones clínicas. Además emite su personal punto de vista en aquellos aspectos que despiertan controversia y comúnmente son resueltos en base a la opinión de reconocidos expertos. Dealing with varicella often causes doubts to general practitioners and pediatricians. In this article the author summaries guidelines based on solid evidence to treat varicella and prevent the disease in susceptible contacts in different clinical scenarios and presents his personal point of view in those controversial aspects commonly resolved by the authorized opinión of experts.

Resumen La necrosis retinal aguda (NRA) es una afecciongrave que amenaza la vision. Se describe en adultos,en especial aquellos profundamente inmunocompro-metidos, como consecuencia de la reactivacion de vi-rus del grupo herpes. Presentamos un paciente de 4anos de edad, con una leucemia de alto riesgo, quedurante una quimioterapia intensa desarrollo una vari-cela con compromiso visceral, incluyendo la retina, loque le causo ceguera unilateral. En el humor vitreo sedetecto ADN de virus varicela-zoster, pese al trata-miento con aciclovir. La vision del ojo contralateralpermanecio indemne. Referencias 1.- Feldman S, Hughes W, Daniel C. Varicella inchildren with cancer: 77 cases. Pediatrics1975; 80: 3882.- Gershon Anne A. Chapter 167: Varicella-Zoster virus. En Feigin RD, Cherry JD,Demmler GJ, Kaplan SL, editors. Textbookof Pediatric Infectious Diseases fifth ed,2004. Elsevier INC USA. Pp: 1962-71.3.- Jura E, Chadwick E G, Josephs S H,Steinberg S P, Yogev R, Gershon A A, et al.Varicella-zoster virus infections in childreninfected with human immunodeficiencyvirus. Pediatr Infect Dis J 1989; 8:586-904.- Srugo I, Israeli V, Wittek A E, Courville T,Vimal V M, Brunell P A. Clinicalmanifestations of varicella-zoster virusinfections in human immunodeficiencyvirus-infected children. Am J Dis Child1992; 147: 742-55.- von Seidlein L, Gillette S G, Bryson Y,Frederick T, Mascola L, Church J, et al.Frequent recurrence and persistente ofvaricella-zoster virus infections in childreninfected with human immunodeficiency virustype 1. J Pediatr 1996; 128: 52-76.- Urayama A, Yamada N, Sasaki T, et al.Unilateral acute uveitis with retinalperiarteritis and detachment. Jpn J ClinOphthalmol 1971; 25: 607-19.7.- Demmler Gail J. Chapter 238: Antiviralagents. En Feigin RD, Cherry JD, DemmlerGJ, Kaplan SL, editors. Textbook ofPediatric Infectious Diseases fifth ed, 2004.Elsevier INC USA. Pp: 3048-74.8.- American Academy of Pediatrics. Antiviraldrugs for non human immunodeficiencyvirus infections. En Pickering LK. Red Book2003; Report of the Committee onInfectious Diseases. 26

Pertussis chemoprophylaxis is indicated for contacts at risk of death or of severe complications if infected with Bordetella pertussis; e.g. neonates and infants

Pertussis chemoprophylaxis is indicated for contacts at risk of death or of severe complications if infected with Bordetella pertussis; e.g. neonates and infantsor= 12 months of age, elderly individuals, individuals with cardiac and/or respiratory insufficiency, and pregnant women during their third trimester of pregnancy (in order to protect their offspring). Available evidence indicates that PChP is effective and thus recommendable for high risk household contacts within a 21 day window after the beginning of symptoms of the index case, and if no secondary case has occurred, recommendation that may be extended to high risk individuals that co-habit with an index case at hospital, daycare centers or institutionalized elderly people. Bordetella pertussis can be transmitted by respiratory droplets that can travel further than the critical distance of 1.5 meters. This long distance transmissibility is relevant when considering who should receive prophylaxis during a nosocomial outbreak. Current evidence supports the use of macrolides and azalides for Pertussis chemoprophylaxis; seven days of erythromycin or clarithromycin and five days of azythromycin are sufficient to eradicate B. pertussis.

El manejo de los pacientes pediátricos con cáncer y neutropenia febril (NF) requiere de su clasificación en alto o bajo riesgo de adquirir infecciones bacterianas invasoras (IBI), con el fin de implementar estrategias selectivas de tratamiento. Basados en nuestra experiencia y publicaciones internacionales al respecto, proponemos recomendaciones para el diagnóstico y manejo de niños con cáncer y NF, categorizadas según riesgo de IBI. Todos los pacientes pediátricos que presenten episodios de NF deben ser ingresados al hospital por al menos 24 horas. Durante este lapso se efectuará su evaluación clínica y de laboratorio con el objeto de clasificar el riesgo de este episodio y precisar el (los) posible(s) foco(s). Los pacientes de alto riesgo deben continuar internados hasta su recuperación. Los de bajo riesgo pueden ser manejados en forma ambulatoria. La elección de la terapia antimicrobiana inicial y los criterios para su ajuste deberán basarse en el hallazgo o no de focos infecciosos y en los patrones epidemiológicos e institucionales de susceptibilidad. La reevaluación de ambos grupos debe ser periódica (al menos en los días 3, 5 y 7 de evolución), y la respuesta terapéutica será clasificada como favorable o desfavorable según criterios clínicos y parámetros de laboratorio preestablecidos