Serological protection induced by Haemophilus influenzae Type B conjugate vaccine in Mexican children: is a booster dose of the vaccine needed?

We determined the seroprevalence of protective antibodies against Hib in Mexican children under the age of five using a standardized enzyme-linked immunosorbent assay. Hib antibodies (≥ 0.15 µg/ml) were present in 95.34% (±1.14% [seroprevalence ± standard error]) of samples. Fewer children aged 30 to 47 months had protective Hib antibody levels (91.45% ± 2.60%) than children from 12 to 29 and 48 to 59 months (97.3% ± 1.34% and 97.44% ± 1.80%, respectively).

An immunological marker (D8/17) associated with rheumatic fever as a predictor of childhood psychiatric disorders in a community sample.

BACKGROUND: Previous studies have documented that various behavioral disturbances accompany Sydenham's chorea, a neurologic variant of rheumatic fever. Further, an immunological marker associated with rheumatic fever (monoclonal antibody D8/17) has been reported to be elevated in several neuropsychiatric disorders, most frequently tics and obsessive-compulsive disorder. We examined this association in a community sample of children previously identified as being D8/17 positive or negative. It was hypothesized that D8/17 positivity would predict increased rates of tics and obsessive-compulsive disorder, even in the absence of Sydenham's chorea. Possible associations with other disorders accompanying Sydenham's chorea--hyperactivity, anxiety, and depression, also were explored. METHOD: From 1991 to 1995, 2631 children (mean age = 9.6 +/- 1.6 years) from a low socioeconomic area of Mexico City were screened for the D8/17 marker. In a 2- to 5-year follow-up of 240 of these children (108 positive and 132 negative), structured psychiatric interviews and rating scales were administered to the child and main caretaker. Assessments were conducted and scored blind to the child's D8/17 status. RESULTS: No association was seen between D8/17 positivity and tics or OCD. CONCLUSION: This study failed to provide support for the generalized use of D8/17 as a marker of susceptibility to tics and OCD in a community sample.

M protein gene type distribution among group A streptococcal clinical isolates recovered in Mexico City, Mexico, from 1991 to 2000, and Durango, Mexico, from 1998 to 1999: overlap with type distribution within the United States.

To examine the type distribution of pathogenic group A streptococcal (GAS) strains in Mexico, we determined the emm types of 423 GAS isolates collected from ill patients residing in Mexico (Durango or Mexico City). These included 282 throat isolates and 107 isolates from normally sterile sites. Of the other isolates, 38 were recovered from other miscellaneous infections. A total of 31 different emm types were found, revealing a broad overlap between commonly occurring emm types in Mexico and the United States. The information obtained in this study is consistent with the possibility that multivalent, M type-specific vaccines prepared for GAS strain distribution within the United States could theoretically protect against the majority of GAS strains causing disease in the two cities surveyed in Mexico.

Carriage of antibiotic-resistant pneumococci in a cohort of a daycare center.

OBJECTIVE: To define epidemiologic relationships to determine the prevalence and potential risk factors for nasopharyngeal colonization by antibiotic-resistant pneumococci, their serotypes and their antibiotic susceptibility patterns in children attending a daycare center (DCC). MATERIAL AND METHODS: A prospective cohort study was conducted among children (n = 53) attending the DCC at Hospital Infantil de México Federico Gómez, which is staffed by 20 employees. Patients were enrolled in the study during a two-year period from September 1997 to September 1999. All the participants were followed prospectively, swabbing them every four months. The strains recovered were typed and screened for susceptibility to several antibiotics. The daycare records were reviewed also. Odds ratios and fisher's exact test: or chi square test of significance were computed from contingency tables as appropriate. Exact 95% confidence intervals were computed for odds ratios. Data analysis was performed using Epi statistics program version 6.04 a. RESULTS: Pneumococci were recovered from 45/53 of the infants at one or more visits. A total of 178 isolates were carried. The carriage rate was 47%. Only 7 adults acquired pneumococci during the study. Types 6, 14, 19 and 23 were prevalent and represented 77% of the total. Antibiotic-resistant strains were higher to penicillin and erythromycin. CONCLUSIONS: Children were frequent carriers of pneumococci, the rate of carriage was high in infancy and tended to decrease with age. The types commonly carried by children were the same as those causing invasive disease. There is a high proportion of carriers with antibiotic-resistant S. pneumoniae strains. Children who have had frequent antimicrobial courses are at particular risk.

Carriage of antibiotic-resistant pneumococci in a cohort of a daycare center

OBJECTIVE: To define epidemiologic relationships to determine the prevalence and potential risk factors for nasopharyngeal colonization by antibiotic-resistant pneumococci, their serotypes and their antibiotic susceptibility patterns in children attending a daycare center (DCC). MATERIAL AND METHODS: A prospective cohort study was conducted among children (n = 53) attending the DCC at Hospital Infantil de MÚxico Federico Gómez, which is staffed by 20 employees. Patients were enrolled in the study during a two-year period from September 1997 to September 1999. All the participants were followed prospectively, swabbing them every four months. The strains recovered were typed and screened for susceptibility to several antibiotics. The daycare records were reviewed also. Odds ratios and fisher's exact test: or chi square test of significance were computed from contingency tables as appropriate. Exact 95 confidence intervals were computed for odds ratios. Data analysis was performed using Epi statistics program version 6.04 a. RESULTS: Pneumococci were recovered from 45/53 of the infants at one or more visits. A total of 178 isolates were carried. The carriage rate was 47. Only 7 adults acquired pneumococci during the study. Types 6, 14, 19 and 23 were prevalent and represented 77 of the total. Antibiotic-resistant strains were higher to penicillin and erythromycin. CONCLUSIONS: Children were frequent carriers of pneumococci, the rate of carriage was high in infancy and tended to decrease with age. The types commonly carried by children were the same as those causing invasive disease. There is a high proportion of carriers with antibiotic-resistant S. pneumoniae strains. Children who have had frequent antimicrobial courses are at particular risk.

Bases fisiopatológicas para la prevención de las infecciones por Streptococcus pneumoniae / Physiopathological bases for preventing streptococcus pneumoniae infections

Streptococcus pneumoniae es un patógeno que coloniza la mucosa respiratoria superior y al mismo tiempo, puede ser la causa de enfermedades sumamente graves como neumonía, bacteriemia, meningitis y septicemia. Es necesario tener conocimiento sobre los factores de virulencia que determinan la dinámica de colonización y la patogénesis de la enfermedad invasiva, con el propósito de poder incidir en alguna etapa de esta enfermedad para su diagnóstico y tratamiento. La resistencia de S. pneumoniae a la penicilina y muchos otros fármacos antimicrobianos es un problema progresivamente creciente. La mejor forma de proteger en contra de las infecciones neumocócicas será mediante el desarrollo de vacunas. La vacuna de polisacárido capsular es mal inmunógeno en niños menores de dos años de edad. La vacuna de polisacárido conjugada a una proteína acarreadora como la heptavalente, es segura e inmunogénica en los niños desde los dos meses de edad y ha probado ser efectiva para proteger en contra de la enfermedad invasiva, e incluso para disminuir el estado de portador nasofaríngeo para los siete serotipos incluidos en la vacuna.

Características de la resistencia antimicrobiana de una colección clínica de Streptococcus pyogenes / Antimicrobial resistance of Streptococcus pyogenes clinical strains

Objetivo. Determinar la susceptibilidad antimicrobiana de Streptococcus pyogenes con el fin de estimar la prevalencia de los fenotipos de resistencia a los macrólidos. Material y métodos. Se realizó un estudio de tipo transversal, en 1999, en el que se evaluaron 100 cepas de S. pyogenes, aislados en el Hospital Infantil de México Federico Gómez, en el lapso comprendido entre 1992 y 1998, procedentes de niños con faringoamigdalitis, conservadas en congelación en el laboratorio de bacteriología hasta su procesamiento. Se determinó la susceptibilidad antimicrobiana a algunos blactámicos, macrólidos y clindamicina. La resistencia a eritromicina se probó por medio de la prueba de difusión de doble disco. Se calcularon medidas de tendencia central. Resultados. Todas las cepas fueron sensibles a los blactámicos y clindamicina; 16 por ciento fueron resistentes a los macrólidos, y todas correspondieron al fenotipo M. Conclusiones. Es conveniente realizar periódicamente pruebas de escrutinio para conocer los posibles cambios en los patrones de sensibilidad estreptocócica.

Características clínico-microbiológicas de la meningitis por Streptococcus pneumoniae resistente a la penicilina / Streptococcus pneumoniae meningitis resistant to penicillin clinical and microbiological characteristics

Objetivo. Evaluar la susceptibilidad antimicrobiana de Streptococcus pneumoniae aislado del líquido cefalorraquídeo de niños con meningitis, así como describir y comparar las características clínicas y microbiológicas, el tratamiento y la evolución del padecimiento entre niños infectados con cepas sensibles y resistentes a la penicilina y la cefalosporina. Material y métodos. Treinta y ocho niños con meningitis neumocóica, durante el lapso 1994-1998. Los datos clínicos y de laboratorio se colectaron de cada expediente. Resultados. Del total de niños, 63 por ciento era menor de dos años de edad, 28.9 por ciento mostró cepas insensible a la penicilina, 18.4 por ciento tenía resistencia intermedia, y 10.5 por ciento tenía resistencia elevada. El 2.6 por ciento mostró también resistencia a la cefotaxima. La única característica (por la prueba exacta de Fisher) asociada con la resistencia fue: enfermedad de base previa al procesos (p< 0.001), y condiciones de gravedad al ingreso como convulsiones, choque tóxico y coma (p< 0.07). El curso de la enfermedad y la evolución clínica fue similar para los niños infectados con cepas sensibles a la penicilina o a la cefotaxima vs. las cepas no susceptibles. Conclusiones. El perfil actual de resistencia del S. pneumoniae a la penicilina y la cefalosporina no se encontró asociado con un aumento en la mortalidad de niños con meningitis neumocóica

Infecciones de vías respiratorias superiores en pediatría / Infections of superior respiratory tracks in pediatrics

El presente documento aborda las tendencias en el tratamiento de las infecciones de vías respiratorias superiores, así como recomendaciones en la elaboración del diagnóstico de alguna enfermedad relacionada, y los síntomas para cada padecimiento, mencionando algunas causas de tos crónica y persistente, investigaciones de laboratorio y gabinete y uso de medicamentos. El libro contiene los siguientes capítulos: I. Diagnóstico y tratamiento de la faringoamigdalitis estreptocócica aguda II. Otitis media aguda III. Sinusitis aguda IV. Crup y otras obstrucciones infecciosas de las vías aéreas superiores V. El niño con tos persistente