RESUMEN
Meningococcal serogroup W strains have been emerging throughout the current century with most of the isolates belonging to the sequence type (ST11)/electrophoretic type (ET37) clonal complex (ST11/E37 CC), particularly since the international outbreak following Hajj 2000. That outbreak appears to have triggered off that trend, contributing to the spread of W ST11/ET37 CC strains globally; however, local strains could be also responsible for increases in the percentage and/or incidence rates of this serogroup in some countries. More recently, unexpected increases in the percentage and incidence rate of W has been noticed in different countries located in the South Cone in Latin America, and W ST11/ET37 CC strains now appear as endemic in the region and an extensive immunization programme with tetravalent conjugate vaccine (covering serogroups A, C, Y and W) has been recently implemented in Chile. It is difficult to ascertain whether we are observing the emergence of W ST11 CC strains in different geographical areas or whether the Hajj 2000 strain is still spreading globally. Several aspects of the evolution of that situation are analysed in this paper, reviewing also the implications in immunization programmes. Closely related with the analysis of this potential evolution, it will be very interesting to monitor the evolution of serogroup W in the African meningitis belt after implementation of the extensive immunization programme with serogroup A conjugate vaccine that is currently underway. More data about carriers, transmission, clonal lineages, etc. are needed for taking decisions (target groups, outbreak control, defining the extent, etc.) to adapt the response strategy with potential interventions with broad coverage vaccines against the emergent serogroup W.
Asunto(s)
Enfermedades Transmisibles Emergentes/microbiología , Brotes de Enfermedades , Infecciones Meningocócicas/microbiología , Vacunas Meningococicas/inmunología , Neisseria meningitidis Serogrupo W-135/inmunología , Argentina/epidemiología , Brasil/epidemiología , Chile/epidemiología , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/inmunología , Enfermedades Transmisibles Emergentes/prevención & control , Brotes de Enfermedades/prevención & control , Salud Global , Humanos , Programas de Inmunización , Incidencia , Infecciones Meningocócicas/epidemiología , Infecciones Meningocócicas/inmunología , Infecciones Meningocócicas/prevención & controlRESUMEN
INTRODUCTION: Cytomegalovirus (CMV) is the most frequent cause of intrauterine infection and an important cause of auditory system damage and mental retardation in humans. Clinical presentation varies from asymptomatic form to lethal systemic dissemination. OBJECTIVES: To describe clinical and laboratories manifestations, age at the moment of diagnostic, treatment and diagnostic test used in congenital cytomegalovirus infection. POPULATION, MATERIAL AND METHODS: Observational, retrospective and descriptive study. Clinical histories of congenital CMV infected infants evaluated by Infectology Department of the Hospital General de Niños Dr. Ricardo Gutiérrez between January 2002 and December 2006 were analyzed. RESULTS: Seventeen patients were evaluated. Mean age at diagnosis was 2.6 months. The most frequent symptom/sign were hepato-splenomegaly (76 %), jaundice (47 %), petechiae and hearing deficit (41 %). Anemia (53 %) and thrombocytopenia (40 %) were the most common laboratory abnormalities. Diagnosis was made exclusively by polymerase chain reaction (PCR)-CMV in one third of the patients, whereas one third was diagnosed by serology and the other third for both test. Five patients received ganciclovir as treatment. Only one had neutropenia. CONCLUSIONS: Differential diagnosis of all newborns with hepatoesplenomegaly, jaundice and petechiae and anemia and/or thrombocytopenia must include congenital cytomegalo-virus infection. Early diagnosis allows a prompt intervention and a strict audiological follow up.
Asunto(s)
Infecciones por Citomegalovirus/congénito , Infecciones por Citomegalovirus/diagnóstico , Infecciones por Citomegalovirus/tratamiento farmacológico , Femenino , Humanos , Lactante , Masculino , Estudios RetrospectivosRESUMEN
BACKGROUND: Early immunization to protect infants against hepatitis A (HA) is recommended in intermediate or high endemic areas of the world, but little is known of the effects of maternal antibodies on the immune response. We studied the immunogenicity and reactogenicity of an inactivated HA vaccine administered in two different schedules to 2-month-old infants in an intermediate/high endemic area in Argentina. METHODS: In this double-blind, randomized study 131 infants received either three doses (at 2, 4, 6 months of age [Group A]) or one dose (at 6 months of age [Group B]) of the pediatric inactivated HA vaccine, Avaxim 80, and a booster dose at 15-18 months. HAV antibodies were measured (ELISA) at 2, 7, 15-18 and 16-19 months of age. Immediate (30 min after injection) and solicited local and systemic reactions were recorded for 7 days after each injection. RESULTS: Of 107/131 subjects (81.6%) who completed the study and who provided final serum samples after booster dose, 94 (87.8%) were seropositive at enrolment (>20 mIU/mL) with geometric mean concentrations (GMC) of 2989 and 3637 mIU/mL in Groups A and B, respectively. One month post-booster GMCs were 8236 mIU/ml (95% CI; 6304, 10760) and 1687 mIU/ml (1148, 2479) in Groups A and B, respectively, with 100% seroprotection. CONCLUSIONS: The HA vaccine was well tolerated and induced immunological priming in both groups during the first year of life in spite of the presence of maternal antibodies. Post-booster GMCs achieved after one or three primary doses suggest a long-term protection against HA.
Asunto(s)
Anticuerpos de Hepatitis A/sangre , Vacunas contra la Hepatitis A/administración & dosificación , Hepatitis A/prevención & control , Esquemas de Inmunización , Argentina , Método Doble Ciego , Femenino , Hepatitis A/inmunología , Vacunas contra la Hepatitis A/efectos adversos , Vacunas contra la Hepatitis A/inmunología , Humanos , Inmunidad Materno-Adquirida , Inmunización Secundaria , Lactante , Masculino , VacunaciónRESUMEN
BACKGROUND: Children are a reservoir of hepatitis A virus and must be considered as primary targets of any immunization strategy. The safety and immunogenicity were evaluated for a new formulation of an inactivated hepatitis A vaccine, Avaxim 80 units, containing one-half the antigen dose of the adult formulation. METHODS: The safety of two doses of this vaccine given 6 months apart was evaluated in an open study in 537 Argentinean children 12 months to 15 years old. Immunogenicity was evaluated at Weeks 0, 2, 24 and 27 in a subgroup of 120 subjects. RESULTS: Two weeks after the first vaccine dose, >99% of initially seronegative children had seroconverted (titers > or =20 mIU/ml), with a geometric mean titer of 98.5 mIU/ml. Before booster at 24 weeks all subjects had seroconverted. A strong anamnestic response was observed after the second dose at which time the geometric mean titer had increased >35-fold, and antibody titers were consistent with long term protection. Immediate adverse reactions were observed in 3 of 537 (0.6%) subjects after the first dose. Local reactions were mild and transient and did not increase with subsequent doses. Among the systemic events reported during the 7-day follow-up period, 37 cases of fever after the first dose and 22 cases after the second dose were reported. Only 3 cases of fever were clearly related to vaccination (< or =38.2 degrees C) after the first injection, all of which subsided in less than 1 day. CONCLUSIONS: This study demonstrated the safety and immunogenicity of a pediatric formulation of hepatitis A vaccine in children ages 12 months to 15 years in healthy children ages 12 to 47 months.
Asunto(s)
Vacunas contra la Hepatitis A/efectos adversos , Vacunas contra la Hepatitis A/inmunología , Anticuerpos Antihepatitis/sangre , Hepatovirus/inmunología , Adolescente , Argentina , Niño , Preescolar , Femenino , Anticuerpos de Hepatitis A , Vacunas contra la Hepatitis A/administración & dosificación , Humanos , Inmunización Secundaria , Lactante , Masculino , Seguridad , Vacunas de Productos Inactivados/administración & dosificación , Vacunas de Productos Inactivados/efectos adversos , Vacunas de Productos Inactivados/inmunologíaRESUMEN
In Latin America, Shigella and shiga toxin-producing Escherichia coli are the two leading agents in the cause of bloody diarrhea. The already high and increasing antimicrobial resistance of Shigella also is a significant problem. Shiga toxin-producing E. coli is an emerging disease with life-threatening complications: hemolytic uremic syndrome. Although E. coli O157:H7 remains the most commonly recognized serotype, recently emerging, non-O157 bacteria may be the cause of a similar spectrum of disease in humans.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Diarrea/microbiología , Disentería Bacilar , Infecciones por Escherichia coli , Escherichia coli , Shigella , Vacunas Bacterianas , Diarrea/epidemiología , Diarrea/terapia , Disentería Bacilar/epidemiología , Disentería Bacilar/microbiología , Disentería Bacilar/terapia , Escherichia coli/inmunología , Infecciones por Escherichia coli/epidemiología , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/terapia , Hemorragia Gastrointestinal/epidemiología , Hemorragia Gastrointestinal/microbiología , Hemorragia Gastrointestinal/terapia , Humanos , América Latina/epidemiología , Toxinas Shiga , Shigella/clasificación , Shigella/inmunologíaAsunto(s)
Infecciones Bacterianas/tratamiento farmacológico , Quimioterapia Combinada/uso terapéutico , Administración Oral , Adolescente , Ampicilina/farmacología , Ampicilina/uso terapéutico , Antibacterianos/uso terapéutico , Argentina , Infecciones Bacterianas/microbiología , Niño , Preescolar , Quimioterapia Combinada/farmacología , Femenino , Bacterias Grampositivas/efectos de los fármacos , Bacterias Grampositivas/aislamiento & purificación , Humanos , Lactante , Masculino , Penicilinas/uso terapéutico , Estudios Prospectivos , Sulbactam/farmacología , Sulbactam/uso terapéutico , Resultado del TratamientoRESUMEN
Argentina has an exceptionally high frequency of hemolytic-uremic syndrome (HUS). We sought to define prospectively the role of verocytotoxins (Shiga-like toxins [SLTs]) in 254 Argentinean children with grossly bloody diarrhea during spring and summer. Free fecal SLTs (I/II) and/or DNA probe-positive isolates were found in 99 (39%) of the children. During the follow-up period, HUS developed in 6 patients (4 with evidence of recent SLT infection based on stool studies); another 14 patients had some, but not all, of the abnormalities seen in typical HUS. The development of HUS or incomplete HUS in these children was significantly associated with recent SLT-Escherichia coli infection (p = 0.024). The high incidence of SLT-associated bloody diarrhea in Argentina explains, at least partially, the unusually high frequency of HUS. Our data indicate that incomplete forms of HUS may be common in patients with SLT-associated bloody diarrhea.
Asunto(s)
Diarrea Infantil/epidemiología , Diarrea/epidemiología , Síndrome Hemolítico-Urémico/epidemiología , Argentina/epidemiología , Toxinas Bacterianas/análisis , Recuento de Células Sanguíneas , Distribución de Chi-Cuadrado , Preescolar , Citotoxinas/análisis , ADN Bacteriano/genética , Diarrea/complicaciones , Diarrea/diagnóstico , Diarrea Infantil/complicaciones , Diarrea Infantil/diagnóstico , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , Heces/química , Heces/microbiología , Femenino , Síndrome Hemolítico-Urémico/diagnóstico , Síndrome Hemolítico-Urémico/etiología , Humanos , Incidencia , Lactante , Masculino , Hibridación de Ácido Nucleico , Estudios Prospectivos , Toxinas ShigaRESUMEN
Hemolytic uremic syndrome (HUS) is thought to be a vascular endothelial injury disease. The mechanism of injury is unknown although verocytotoxins (Shiga-like toxins (SLTs)) are known to be associated with it. Recent evidence suggests that in vitro treatment of some endothelial cells with tumor necrosis factor alpha (TNF-alpha) dramatically increases their susceptibility to SLTs. We studied 25 children with HUS, 63 children with SLT-positive bloody diarrhea, 62 children with bloody diarrhea not associated with SLTs and 39 children admitted for elective surgery, included as an age- and season-matched control group. The TNF-alpha concentrations were found to be significantly elevated in children with HUS (range, 1 to 95 pg/ml; geometric mean, 32.2 pg/ml) compared with the healthy controls (range, 0 to 53 pg/ml; mean, 12.5 pg/ml; P < 0.001). Because it is hypothesized that TNF-alpha elevation might precede development of HUS, we also studied children with blood diarrhea. The TNF-alpha serum concentrations were significantly higher during the first 10 days after onset of bloody diarrhea than after the first 10 days (P < 0.02). Such elevation could be associated with vascular endothelial glycolipid receptor up-regulation and increased susceptibility to the effects of SLTs.
Asunto(s)
Síndrome Hemolítico-Urémico/sangre , Síndrome Hemolítico-Urémico/fisiopatología , Factor de Necrosis Tumoral alfa/análisis , Argentina , Estudios de Casos y Controles , Preescolar , Diarrea/etiología , Heces/microbiología , Femenino , Síndrome Hemolítico-Urémico/complicaciones , Humanos , Inmunoensayo , Lactante , Masculino , PronósticoRESUMEN
From January, 1990, to December 31, 1990, 75 children with multiply resistant Salmonella gastroenteritis were studied at the Children's Hospital "Ricardo Gutierrez" of Buenos Aires. These children ranged from 1 month to 15 years of age. Infection was community-acquired in 20 (26.6%), nosocomially acquired in 50 (66.7%) and undetermined in 5. Thirty-nine (52%) had grossly bloody stools. Fever occurred at some point in the clinical course in 61 children (81.3%) with a duration of 1 to 33 days (mean, 6.7 days). The duration of diarrhea (1 to 69 days) was longer in those who developed complications (P < 0.001). Six (8%) developed enterocolitis (2 with bowel perforation), 1 had a pulmonary abscess and 8 (11.4%) had bacteremia; 4 children died (5.3%). Salmonella typhimurium was the most common serovar (85.3%). Ninety percent minimum inhibitory concentration studies demonstrated that all strains were resistant to ampicillin (> 128 micrograms/ml), cephalothin (> 128 micrograms/ml), cefuroxime (> 128 micrograms/ml), nalidixic acid (> 256 micrograms/ml), rifampin (> 256 micrograms/ml), gentamicin (> 256 micrograms/ml) and tobramycin (256 micrograms/ml); 77.3% of strains were resistant to ceftazidime (32 micrograms/ml), 97.6% to netilmicin (> 256 micrograms/ml), 92.8% to amikacin (256 micrograms/ml), 24.4% to isepamicin (32 micrograms/ml), 5.3% to chloramphenicol (4 micrograms/ml) and 2.7% to cefoxitin (2 micrograms/ml). The 90% minimum inhibitory concentration of cefotaxime and ceftazidime was reduced by the addition of clavulanate. Aggressive multiply resistant Salmonella strains are a major pediatric problem in Buenos Aires.
Asunto(s)
Farmacorresistencia Microbiana , Gastroenteritis/microbiología , Infecciones por Salmonella/microbiología , Salmonella/efectos de los fármacos , Adolescente , Aminoglicósidos , Antibacterianos , Argentina , Cefalosporinas , Niño , Preescolar , Femenino , Gastroenteritis/complicaciones , Humanos , Lactante , Masculino , Salmonella/aislamiento & purificación , Infecciones por Salmonella/complicacionesRESUMEN
To determine whether severity of the prodromal gastrointestinal illness is associated with the course and complications of the extraintestinal manifestations of hemolytic-uremic syndrome, we conducted a retrospective review of children (n = 509) hospitalized with hemolytic-uremic syndrome. Those who came to the hospital with colitis and rectal prolapse associated with hemolytic-uremic syndrome (group I, n = 40) were compared with an equal number of time-matched children with hemolytic-uremic syndrome but without prolapse (group II). Children in group I had evidence of more severe colitis than children in group II had, as indicated by increased frequency of bloody diarrhea (p less than 0.001) and longer duration of diarrhea (p less than 0.001). However, they also had more severe extraintestinal manifestations during hemolytic-uremic syndrome, including edema (p less than 0.0001), severe thrombocytopenia (p less than 0.0001), prolonged anuria (p less than 0.001), and seizures (p = 0.036). Long-term prognosis for recovery of renal function was worse for group I than group II. Within group II, patients with bloody diarrhea had milder extraintestinal illness than those with prolapse but more severe extraintestinal illness than those with watery diarrhea. Analysis of Kaplan-Meier survival curves demonstrated a better prognosis for return of normal renal function in the children with watery diarrhea but without prolapse (p = 0.009) than in children with bloody diarrhea or prolapse. These data demonstrate that the severity of the gastrointestinal prodrome reflects the severity of the extraintestinal acute microangiopathic process and the resulting long-term outcome. Widespread vascular damage, often followed by permanent sequelae, is characteristic of patients with the most severe colitis.
Asunto(s)
Enfermedades Gastrointestinales/complicaciones , Síndrome Hemolítico-Urémico/complicaciones , Adolescente , Colitis/complicaciones , Femenino , Síndrome Hemolítico-Urémico/diagnóstico , Síndrome Hemolítico-Urémico/fisiopatología , Humanos , Riñón/fisiopatología , Masculino , Pronóstico , Prolapso Rectal/complicaciones , Estudios RetrospectivosRESUMEN
We conducted a prospective study in 87 household contacts of 51 children with hemolytic uremic syndrome to determine the frequency of infection with Shiga-like toxin-producing bacteria. Gastrointestinal tract symptoms occurred in only 1 of 87 contacts. Free fecal toxin was detected in 25 of 64 (39%) of the household members. Neutralization with specific antisera to Shiga-like toxins I and II (SLT-I, SLT-II) revealed that in 6 of these household contacts only SLT-I was present in stool, in 10 only SLT-II was present and in 9 both toxins were found. Thirty-three percent of the hemolytic uremic syndrome families in which 2 or more members were studied had more than 1 household member with free fecal toxin in stool. None of the household contacts was found to have E. coli O157:H7 in feces. Serum samples were available in 77 household contacts; 75% (58 of 77) had serum neutralizing titers of greater than or equal to 1:4 to 1 or both toxins. In those contacts for whom paired sera were available, seroconversion was found in 10 of 24 (42%). These data show that household contacts of children with hemolytic uremic syndrome are commonly colonized with Shiga-like toxin-producing E. coli and seroconversion to Shiga-like toxins occurs frequently in family members of children with hemolytic uremic syndrome.
Asunto(s)
Toxinas Bacterianas/biosíntesis , Infecciones por Escherichia coli/microbiología , Escherichia coli/metabolismo , Síndrome Hemolítico-Urémico/etiología , Adulto , Argentina/epidemiología , Portador Sano/epidemiología , Portador Sano/microbiología , Niño , Infecciones por Escherichia coli/epidemiología , Heces/microbiología , Femenino , Humanos , Masculino , Estudios Prospectivos , Toxina Shiga I , Toxina Shiga IIRESUMEN
Shiga-like toxin-producing Escherichia coli have been associated with hemorrhagic colitis and the hemolytic uremic syndrome (HUS). Because Argentina has the highest reported frequency of HUS in the world, Argentine children were prospectively studied during the HUS seasons for evidence of Shiga-like toxin-related diseases. On the basis of serology, fecal cytotoxin neutralization, stool cultures, and DNA hybridization of colony lysates, most children with HUS had evidence of infection with Shiga-like toxin-producing organisms. Children with spring-summer diarrhea also commonly (32%, confidence interval 18%-46%) had clear-cut evidence of such infection. No controls (children without gastrointestinal, renal, or hemolytic disease) had free fecal cytotoxin, positive cultures for E. coli O157:H7, or DNA probe-positive organisms; 20% of them had low serum titers of antibodies to Shiga-like toxins. E. coli O157:H7 was not common in either HUS or diarrhea patients. The high frequency of Shiga-like toxin-induced diarrhea in young children in Argentina probably explains the high incidence of HUS in this country and suggests that HUS is a relatively uncommon complication of Shiga-like toxin-related disease.
Asunto(s)
Toxinas Bacterianas/aislamiento & purificación , Diarrea/microbiología , Infecciones por Escherichia coli/complicaciones , Síndrome Hemolítico-Urémico/microbiología , Argentina , Niño , Citotoxinas/aislamiento & purificación , Escherichia coli/aislamiento & purificación , Heces/microbiología , Humanos , Estudios Prospectivos , Toxina Shiga I , Toxina Shiga II , Shigella dysenteriae/aislamiento & purificaciónAsunto(s)
Faringitis/diagnóstico , Infecciones Estreptocócicas/diagnóstico , Streptococcus pyogenes/aislamiento & purificación , Antígenos Bacterianos/análisis , Argentina , Niño , Reacciones Falso Negativas , Reacciones Falso Positivas , Humanos , Pruebas de Fijación de Látex , Faringe/microbiología , Valor Predictivo de las Pruebas , Juego de Reactivos para Diagnóstico , Streptococcus pyogenes/inmunología , Factores de TiempoAsunto(s)
Recién Nacido , Lactante , Preescolar , Niño , Humanos , Masculino , Femenino , Meningitis , Tomografía Computarizada por Rayos X , Encefalitis , Hidrocefalia , Efusión SubduralAsunto(s)
Recién Nacido , Lactante , Preescolar , Niño , Humanos , Masculino , Femenino , Meningitis , Tomografía Computarizada por Rayos X , Efusión Subdural , Encefalitis , HidrocefaliaRESUMEN
The serum of 50 patients between 25 days to 15 years old who were admitted with the diagnosis of pertussis syndrome were investigated for precipitating antibodies by means of discontinuous counterimmunolectrophoresis (CIED). The presence of antibodies for Bordetella pertussis antigen was shown in 28 cases. All samples were taken within the first 24/48 hours of admission and at convalescence. The technique is easy to carry out, quick and of low cost. This test offers an adequate and fast means to differentiate a Bordetella pertussis syndrome form others produced by different viral etiologies. Besides, this serologic technique shows earlier results and of lower cost than classic techniques such as agglutination and complement fixation which are more difficult to apply.