RESUMO
The aim of this study was to determine the frequency and allele associations of locus of enterocyte effacement encoded esp and tir genes among 181 enteropathogenic Escherichia coli (EPEC) strains (90 diarrhoea-associated and 91 controls) isolated from Peruvian children under 18 months of age. We analysed espA, espB, espD and tir alleles by PCR-RFLP. EPEC strains were isolated with higher frequency from healthy controls (91/424, 21.7%) than from diarrhoeal samples (90/936, 9.6%) (P<0.001); 28.9% of diarrhoeal and 17.6% of control samples were typical EPEC (tEPEC). The distribution of espA alleles (alpha, beta, beta2 and gamma) and espD alleles (alpha, beta, gamma and a new variant, espD-N1) between tEPEC and atypical EPEC (aEPEC) was significantly different (P<0.05). espD-alpha was more common among acute episodes (P<0.05). espB typing resulted in five alleles (alpha, beta, gamma and two new sub-alleles, espB-alpha2 and espB-alpha3), while tir-beta and tir-gamma2 were the most common intimin receptor subtypes. Seventy-two combinations of espA, espB, espD and tir alleles were found; the most prevalent combination was espA-beta, espB-beta, espD-beta, tir-beta (34/181 strains), which was more frequent among tEPEC strains (P<0.05). Our findings indicate that there is a high degree of heterogeneity among EPEC strains isolated from Peruvian children and that aEPEC and tEPEC variants cluster.
Assuntos
Escherichia coli Enteropatogênica/genética , Escherichia coli Enteropatogênica/isolamento & purificação , Infecções por Escherichia coli/epidemiologia , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Variação Genética , Fosfoproteínas/genética , Criança , Pré-Escolar , Impressões Digitais de DNA , DNA Bacteriano/química , DNA Bacteriano/genética , Genótipo , Humanos , Lactente , Epidemiologia Molecular , Dados de Sequência Molecular , Peru , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Análise de Sequência de DNARESUMO
The aim of this study was to determine the prevalence, virulence factors (stx, eae, ehxA and astA) and phylogenetic relationships [PFGE and multilocus sequence typing (MLST)] of Shiga toxin-producing Escherichia coli (STEC) strains isolated from four previous cohort studies in 2212 Peruvian children aged <36 months. STEC prevalence was 0.4â% (14/3219) in diarrhoeal and 0.6â% (15/2695) in control samples. None of the infected children developed haemolytic uraemic syndrome (HUS) or other complications of STEC. stx1 was present in 83â% of strains, stx2 in 17â%, eae in 72â%, ehxA in 59â% and astA in 14â%. The most common serotype was O26â:âH11 (14â%) and the most common seropathotype was B (45â%). The strains belonged mainly to phylogenetic group B1 (52â%). The distinct combinations of alleles across the seven MLST loci were used to define 13 sequence types among 19 STEC strains. PFGE typing of 20 STEC strains resulted in 19 pulsed-field patterns. Comparison of the patterns revealed 11 clusters (I-XI), each usually including strains belonging to different serotypes; one exception was cluster VI, which gathered exclusively seven strains of seropathotype B, clonal group enterohaemorrhagic E. coli (EHEC) 2 and phylogenetic group B1. In summary, STEC prevalence was low in Peruvian children with diarrhoea in the community setting. The strains were phylogenetically diverse and associated with mild infections. However, additional studies are needed in children with bloody diarrhoea and HUS.
Assuntos
Infecções por Escherichia coli/microbiologia , Escherichia coli Shiga Toxigênica/classificação , Escherichia coli Shiga Toxigênica/genética , Adesinas Bacterianas/genética , Sequência de Bases , Estudos de Casos e Controles , Pré-Escolar , Estudos de Coortes , DNA Bacteriano/genética , Eletroforese em Gel de Campo Pulsado , Infecções por Escherichia coli/epidemiologia , Proteínas de Escherichia coli/genética , Feminino , Genes Bacterianos , Proteínas Hemolisinas/genética , Humanos , Lactente , Recém-Nascido , Masculino , Tipagem de Sequências Multilocus , Peru/epidemiologia , Filogenia , Prevalência , Sorotipagem , Toxina Shiga/genética , Escherichia coli Shiga Toxigênica/isolamento & purificação , Fatores de Virulência/genéticaRESUMO
Enteropathogenic Escherichia coli (EPEC) is a leading cause of infantile diarrhoea in developing countries. The aim of this study was to describe the allelic diversity of critical EPEC virulence genes and their association with clinical characteristics. One hundred and twenty EPEC strains isolated from a cohort diarrhoea study in Peruvian children were characterized for the allele type of eae (intimin), bfpA (bundlin pilin protein of bundle-forming pilus) and perA (plasmid encoded regulator) genes by PCR-RFLP. Atypical EPEC strains (eae+, bfp-) were the most common pathotype in diarrhoea (54/74, 73 %) and control samples from children without diarrhoea (40/46, 87 %). Overall, there were 13 eae alleles; the most common were beta (34/120, 28 %), theta (24/120, 20 %), kappa (14/120, 12 %) and mu (8/120, 7 %). There were five bfpA alleles; the most common were beta1/7 (10/26), alpha3 (7/26) and beta5 (3/26). There were three perA alleles: beta (8/16), alpha (7/16) and gamma (1/16). The strains belonged to 36 distinct serogroups; O55 was the most frequent. The gamma-intimin allele was more frequently found in diarrhoea episodes of longer duration (>7 days) than those of shorter duration (3/26, 12 % vs 0/48, 0 %, P<0.05). The kappa-intimin allele had the highest clinical severity score in comparison with other alleles (P<0.05). In Peruvian children, the virulence genes of EPEC strains are highly variable. Further studies are needed to evaluate additional virulence markers to determine whether relationships exist between specific variants and clinical features of disease.
Assuntos
Adesinas Bacterianas/genética , Escherichia coli Enteropatogênica/metabolismo , Infecções por Escherichia coli/microbiologia , Proteínas de Escherichia coli/genética , Proteínas de Fímbrias/genética , Proteínas Repressoras/genética , Adesinas Bacterianas/metabolismo , Criança , Estudos de Coortes , Diarreia/epidemiologia , Diarreia/microbiologia , Escherichia coli Enteropatogênica/genética , Infecções por Escherichia coli/epidemiologia , Proteínas de Escherichia coli/metabolismo , Proteínas de Fímbrias/metabolismo , Humanos , Peru/epidemiologia , Proteínas Repressoras/metabolismo , VirulênciaRESUMO
Hemolytic uremic syndrome, a serious complication of Shiga toxin-associated diarrhea, is rare before 6 months of age. Immunologic and nonimmunologic factors present in human milk may partially explain this observation. In prior studies, we have demonstrated that human milk contains Gb3, the receptor for the B subunit of Shiga toxin, and also contains secretory IgA (sIgA) against the toxin. We therefore sought to determine the relative importance of milk glycolipid and toxin-specific sIgA in toxin binding. We studied two populations that differed in their frequency of exposure to Shiga toxin. Human milk samples obtained from healthy donors from Boston and Buenos Aires were separated by centrifugation into aqueous (antibody enriched) and cream (glycosphingolipid enriched) fractions. An emulsion of equal volumes of aqueous phase or cream layer of each sample and purified Shiga toxin was incubated, and the amount of free toxin present in each was determined by enzyme immunoassay. The cream layers bound 85%+/-2 (mean +/- SE) (Argentina milk samples) and 86%+/-1 (Boston milk samples) of Shiga toxin. In contrast, the soluble fraction in samples from Buenos Aires, a population expected to frequently have antibodies to Shiga toxin, bound more toxin (48%+/-2) than did this fraction in samples from Boston, an area where toxin exposure is infrequent (30%+/-3) (P < 0.0001). Toxin-binding lipids present in human milk are biologically active and may contribute to the putative protective effect of human milk. In a population frequently exposed to Shiga toxins (Argentina), protection may be due to both immune (sIgA), and nonimmune (lipid) factors present in human milk. In a population infrequently exposed to Shiga toxins, cream fraction-associated glycolipids represent the major toxin binding activity in human milk.
Assuntos
Glicolipídeos/metabolismo , Leite Humano/química , Toxina Shiga/metabolismo , Argentina , Boston , Cromatografia Líquida de Alta Pressão , Feminino , Glicolipídeos/análise , Glicolipídeos/isolamento & purificação , HumanosRESUMO
An infant had clinical signs suggestive of Hirschsprung disease as the initial manifestation of leukocyte adhesion deficiency. Chromosome studies showed a deletion of the distal third of the long arm of one chromosome 21, and flow cytometric studies confirmed the defective expression of CD18.
Assuntos
Doença de Hirschsprung/diagnóstico , Síndrome da Aderência Leucocítica Deficitária/diagnóstico , Antígenos CD11/sangue , Antígenos CD18/sangue , Deleção Cromossômica , Cromossomos Humanos Par 21 , Diagnóstico Diferencial , Evolução Fatal , Doença de Hirschsprung/genética , Humanos , Lactente , Síndrome da Aderência Leucocítica Deficitária/genética , MasculinoRESUMO
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.
Assuntos
Diarreia Infantil/epidemiologia , Diarreia/epidemiologia , Síndrome Hemolítico-Urêmica/epidemiologia , Argentina/epidemiologia , Toxinas Bacterianas/análise , Contagem de Células Sanguíneas , Distribuição de Qui-Quadrado , Pré-Escolar , Citotoxinas/análise , DNA Bacteriano/genética , Diarreia/complicações , Diarreia/diagnóstico , Diarreia Infantil/complicações , Diarreia Infantil/diagnóstico , Escherichia coli/genética , Escherichia coli/isolamento & purificação , Fezes/química , Fezes/microbiologia , Feminino , Síndrome Hemolítico-Urêmica/diagnóstico , Síndrome Hemolítico-Urêmica/etiologia , Humanos , Incidência , Lactente , Masculino , Hibridização de Ácido Nucleico , Estudos Prospectivos , Toxinas ShigaRESUMO
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.
Assuntos
Síndrome Hemolítico-Urêmica/sangue , Síndrome Hemolítico-Urêmica/fisiopatologia , Fator de Necrose Tumoral alfa/análise , Argentina , Estudos de Casos e Controles , Pré-Escolar , Diarreia/etiologia , Fezes/microbiologia , Feminino , Síndrome Hemolítico-Urêmica/complicações , Humanos , Imunoensaio , Lactente , Masculino , PrognósticoRESUMO
The proportion of Shigella infections that occur asymptomatically in young children has not been established. A community-based cohort study of 367 infants was followed prospectively by weekly home visits from January, 1990, through December, 1991. Stool samples were collected weekly and when diarrhea occurred and were tested for Shigella and other enteropathogens. There were 2925 child months of observation and 65 episodes of Shigella infection. There were 3.1 episodes/100 child months during the warm season (May through September) and 0.97 episode/100 child months during the cold season. Shigella infections were rare during the first 6 months of life but increased with age (P < 0.0001). Overall 55% of detected infections were asymptomatic. The proportion of infections that were asymptomatic increased as age increased (P < 0.01). Symptom status was not significantly associated with Shigella species or season. All isolates from symptomatic and asymptomatic children had the 120- to 140-megadalton virulence plasmid. We conclude that infections with virulent strains of Shigella are commonly asymptomatic in Mexican children during the first 2 years of life.
PIP: During January 1990-December 1991, each week, field workers visited the home of 367 children aged 0-24 months from a periurban area southwest of Mexico City (San Pedro Martir and San Andres Totoltepec, Tlalpan) and collected stool specimens from them to determine whether Shigella infections are often asymptomatic. The crude incidence rate of diarrhea, regardless of etiology, was 29 episodes/100 child months during the warmer and rainy months (May-September), while it was 21 episodes/100 child months for the rest of the year (October-April) (relative risk [RR] =1.38). 53 of all children (l4%) had 65 Shigella infections. The overall monthly incidence of symptomatic and asymptomatic Shigella infection was higher during May-September than October-April (3.13 vs. 0.97 episodes/100 children; RR = 3.22). 55% of all Shigella infections (36) were asymptomatic. 32% developed secretory-type diarrhea and 13% had blood present in the stool. The incidence of Shigella infections grew as did the age (0.4-8.2 episodes/100 child months for 0-6 month olds to 18-24 month olds; p 0.0001). The proportion of asymptomatic Shigella infections also increased with age (33% for 0-6 month olds, 40% for 7-12 month olds, 46% for 13-18 month olds, and 78% for 18-24 month olds; p 0.01). Shigella sonnei, S. flexneri, and S. boydii were the only species detected. The 120-140 megadalton virulence plasmid was present in all isolates from asymptomatic and symptomatic children. Mixed infections were rather common in both asymptomatic (47%) and symptomatic (45%) children. Among infants aged less than 12 year months, breast feeding infants were less likely to be infected with Shigella than nonbreast feeding infants (RR = 2.41). On the other hand, among children aged 12-24 months, nonbreast feeding was associated with a lower risk of Shigella infection (RR = 0.69). These findings show that Shigella infections in Mexican children aged 0-24 months range from asymptomatic infections to secretory diarrhea to bloody diarrhea.
Assuntos
Disenteria Bacilar/epidemiologia , Distribuição por Idade , Aleitamento Materno , Estudos de Coortes , Intervalos de Confiança , Disenteria Bacilar/microbiologia , Disenteria Bacilar/fisiopatologia , Fezes/microbiologia , Humanos , Incidência , Lactente , Recém-Nascido , México/epidemiologia , Estudos Prospectivos , Estações do Ano , Shigella boydii/isolamento & purificação , Shigella flexneri/isolamento & purificação , Shigella sonnei/isolamento & purificaçãoRESUMO
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.
Assuntos
Resistência Microbiana a Medicamentos , Gastroenterite/microbiologia , Infecções por Salmonella/microbiologia , Salmonella/efeitos dos fármacos , Adolescente , Aminoglicosídeos , Antibacterianos , Argentina , Cefalosporinas , Criança , Pré-Escolar , Feminino , Gastroenterite/complicações , Humanos , Lactente , Masculino , Salmonella/isolamento & purificação , Infecções por Salmonella/complicaçõesRESUMO
In a prospective randomized double-blind trial, pivmecillinam was compared with cotrimoxazole (TMP-SMX), both given orally for a period of 5 days, for the treatment of 59 children with shigellosis. 29 patients were treated with pivmecillinam and 30 with cotrimoxazole. 14% of shigella organisms isolated were resistant to pivmecillinam and 21% to TMP-SMX. The diarrhea persisted for a mean (+/- SD) period of 74 +/- 24.8 h in the pivmecillinam-treated patients versus 73.8 +/- 34 h in the TMP-SMX-treated patients. Duration of fever, positive stool culture, visible blood, occult blood, and pus cells in the stools were similar for both treatment groups. Five patients (17%) in the pivmecillinam group and 4 patients (13%) in the cotrimoxazole group fulfilled the clinical criteria that defined treatment failure. One patient (3.4%) in the pivmecillinam group and 2 (6.6%) in the TMP-SMX group evidenced recurrence of the diarrheal symptoms at the follow-up visit. No major drug-related side effects were observed in either group. We concluded that pivmecillinam is equivalent to cotrimoxazole in the treatment of shigellosis in children.
Assuntos
Andinocilina Pivoxil/uso terapêutico , Disenteria Bacilar/tratamento farmacológico , Shigella/efeitos dos fármacos , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Doença Aguda , Adolescente , Andinocilina Pivoxil/farmacologia , Criança , Pré-Escolar , Método Duplo-Cego , Disenteria Bacilar/microbiologia , Feminino , Humanos , Lactente , Masculino , Estudos Prospectivos , Shigella/isolamento & purificaçãoRESUMO
We conducted a prospective, community-based study of healthy breast-fed Mexican infants to determine the protective effects of anti-Shigella secretory IgA antibodies in milk. Milk samples were collected monthly, and stool culture specimens were obtained weekly and at the time of episodes of diarrhea. Nineteen breast-fed infants were found to have Shigella flexneri, Shigella boydii, or Shigella sonnei in stool samples. Ages of the 10 infants with symptomatic infection and the nine with asymptomatic infection did not differ significantly. Milk samples collected up to 12 weeks before infection were evaluated by enzyme-linked immunosorbent assay for secretory IgA antibodies against lipopolysaccharides of S. flexneri, S. boydii serotype 2, S. sonnei, and virulence plasmid-associated antigens. The geometric mean titers of anti-Shigella antibodies to virulence plasmid-associated antigens in milk received before infection were eightfold higher in infants who remained well than in those in whom diarrhea developed. The significance of milk secretory IgA directed against lipopolysaccharide was less clear. We conclude that human milk protects infants against symptomatic shigella infection when it contains high concentrations of secretory IgA against virulence plasmid-associated antigens.
Assuntos
Antígenos de Bactérias/imunologia , Aleitamento Materno , Disenteria Bacilar/imunologia , Imunoglobulina A Secretora/análise , Leite Humano/imunologia , Plasmídeos/imunologia , Shigella boydii/imunologia , Shigella flexneri/imunologia , Shigella sonnei/imunologia , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/microbiologia , Ensaio de Imunoadsorção Enzimática , Fezes/microbiologia , Humanos , Lactente , Recém-Nascido , México/epidemiologia , Prognóstico , Estudos Prospectivos , Estudos Soroepidemiológicos , Shigella boydii/isolamento & purificação , Shigella boydii/patogenicidade , Shigella flexneri/isolamento & purificação , Shigella flexneri/patogenicidade , Shigella sonnei/isolamento & purificação , Shigella sonnei/patogenicidade , População Urbana/estatística & dados numéricos , Virulência/imunologiaRESUMO
In a prospective randomized study at two clinical sites, ceftibuten was compared with trimethoprim-sulfamethoxazole (TMP-SMX), both given orally for a period of 5 days, for the treatment of dysentery. Twenty-two children were found to have bacillary dysentery caused by Shigella and/or enteroinvasive Escherichia coli. All organisms isolated were susceptible to ceftibuten; 6 of 20 Shigella strains and 4 of 5 enteroinvasive E. coli were resistant to TMP-SMX. The diarrhea persisted for a mean (+/- SD) period of 2.4 +/- 1.4 days in the ceftibuten-treated patients vs. 3.4 +/- 1.7 days in the TMP-SMX-treated patients. The duration of fever was similar for both treatment groups. Patients treated with ceftibuten or TMP-SMX had equivalent clinical responses unless the pathogen was found to be TMP-SMX-resistant. Those who were randomized to receive TMP-SMX but who were eventually found to have TMP-SMX-resistant organisms had significantly more stools at days 3, 4 and 5 (P less than 0.02 to less than 0.00006) with more watery consistency for these days (P less than 0.02 to less than 0.005) compared to patients treated with ceftibuten. No clinical relapses were reported and no drug-related side effects were observed. We conclude that ceftibuten is at least as effective as TMP-SMX in the treatment of diarrhea caused by Shigella and enteroinvasive E. coli in children.
Assuntos
Cefalosporinas/uso terapêutico , Disenteria Bacilar/tratamento farmacológico , Infecções por Escherichia coli/tratamento farmacológico , Combinação Trimetoprima e Sulfametoxazol/uso terapêutico , Adolescente , Ceftibuteno , Criança , Pré-Escolar , Humanos , Lactente , Estudos ProspectivosRESUMO
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.
Assuntos
Gastroenteropatias/complicações , Síndrome Hemolítico-Urêmica/complicações , Adolescente , Colite/complicações , Feminino , Síndrome Hemolítico-Urêmica/diagnóstico , Síndrome Hemolítico-Urêmica/fisiopatologia , Humanos , Rim/fisiopatologia , Masculino , Prognóstico , Prolapso Retal/complicações , Estudos RetrospectivosRESUMO
Although antibodies to the lipopolysaccharide antigens of Shigella have been demonstrated in human milk, such antibodies do not explain the putative protective effect of breast-feeding against symptomatic Shigella infection. Shigella species do not share related lipopolysaccharides, but they do possess closely related virulence plasmids that code for the proteins essential for cell invasion. We therefore sought to determine the frequency, amount, and duration of excretion of human milk antibodies to these shared virulence plasmid-associated antigens in populations of different rates of Shigella infection frequency (Mexico City, high; Houston, low). Such antibodies were present in the milk of virtually all the Mexican women but also were present in a large proportion of milk samples from the women living in Houston. The amounts of these antibodies were highest in colostrum but after 2 weeks of lactation fell to stable levels. The frequency and persistence of these antibodies in the milk of the women from Houston suggest that the memory and drive for secretion of these antibodies is extremely long lived.
Assuntos
Anticorpos Antibacterianos/análise , Imunoglobulina A Secretora/análise , Leite Humano/imunologia , Plasmídeos , Shigella/imunologia , Antígenos de Bactérias/imunologia , Colostro/química , Colostro/imunologia , Feminino , Humanos , Imunoglobulina A Secretora/imunologia , Leite Humano/química , Shigella/patogenicidade , VirulênciaRESUMO
PIP: 20 Mexico City and 23 Houston, Texas colostrum samples, and 21 Mexican and 25 Houston mature milk samples were analyzed by ELISA and Western blot, respectively, for antibodies against the virulence plasmid of Shigella flexneri serotype 5 strain M9OT. The method involved comparing water extracts of milk in ELISA and Western blot determinations of antigens against shigella flexneri strain M9OT which is fully virulent, to those against M9OT A2 which lacks the virulence plasmid. While there are at least 37 know distinct lipopolysaccharide antigens on different strains of the 4 species of Shigella, all contain the same plasmid conferring virulence, the ability of the bacteria to invade mammalian cells. This provided a universal test for antigens to Shigella. Western blots showed antibodies in all 21 Mexican women and in 40% of 25 Houston women. Plasmid antibodies were detected by ELISA in all 20 Mexican colostrum samples and in 52% of 23 Houston colostrum samples. After 8 days of lactation, 93% of the Mexican and 46% of the Houston milk samples were positive. The actual protective factor in human milk against Shigella bacteria is unknown: these findings suggest a mechanism for protection against all serotypes of shigella. The high prevalence of antibodies against Shigella found in Houston women was attributed to infection in the distant past.^ieng
Assuntos
Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/imunologia , Imunoglobulina A Secretora/imunologia , Leite Humano/imunologia , Shigella/imunologia , Antígenos de Bactérias/genética , Linfócitos B/imunologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Movimento Celular , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/prevenção & controle , Feminino , Humanos , México/epidemiologia , Plasmídeos , Shigella/genética , Shigella/patogenicidade , Texas/epidemiologia , VirulênciaRESUMO
The pathogenesis of primary (classic) hemolytic-uremic syndrome (HUS) is thought to be related to cytotoxin-producing enteric pathogens such as Shigella dysenteriae serotype 1 and Escherichia coli serotypes O157:H7 and 026:H11. The relevant cytotoxins include Shiga toxin and the closely related Shiga-like toxins (SLTs) produced by some E. coli strains. Intravenously administered immune globulin (IVIG) therapy has been reported to be beneficial in a few children with HUS. We therefore examined commercially available immune globulin preparations for the presence of anticytotoxin-neutralizing antibodies. Cytotoxicity and neutralization of the HUS-associated cytotoxins were quantitatively determined by means of a (3H)thymidine-labeled HeLa cell assay. The immune globulin preparations tested almost completely neutralized Shiga toxin (produced by S. dysenteriae 1) and SLT-I (produced by E. coli serotype 026:H11). Twofold dilutions of the preparations showed significant (p less than 0.01) neutralizing titers of 1:64 to 1:128. No significant neutralization (greater than 20%) of SLT-II (produced by E. coli strain C600 (933W] was noted. The IVIG preparation lost its inhibitory activity when passed through a protein A-Sepharose column, which bound immune globulin, indicating that its neutralizing effect is related to the antibody content. We also examined sera from 30 children without diarrhea or HUS; only one child had neutralizing titers against Shiga toxin (1:64) and SLT-I (1:128). Immune globulin preparations contain anticytotoxin-neutralizing antibodies, a finding that warrants further investigation of the therapeutic role of these preparations in early treatment of children with HUS related to Shiga toxin and SLT-I.
Assuntos
Anticorpos Antibacterianos/administração & dosagem , Citotoxinas/imunologia , Escherichia coli/imunologia , Síndrome Hemolítico-Urêmica/terapia , Imunização Passiva/métodos , Testes de Neutralização , Shigella dysenteriae/imunologia , Adolescente , Criança , Pré-Escolar , Citotoxicidade Imunológica , Diarreia Infantil/terapia , Disenteria Bacilar/terapia , Infecções por Escherichia coli/terapia , Células HeLa/imunologia , Síndrome Hemolítico-Urêmica/imunologia , Humanos , LactenteRESUMO
Thirty-six patients with AIDS and culture-proven nontuberculous mycobacteriosis were compared to 20 patients with acquired immunodeficiency syndrome (AIDS) and tuberculosis with regard to clinical signs, symptoms, and diagnostic methods. Patients with nontuberculous mycobacteriosis were more often younger and homosexuals, while patients with tuberculosis were usually Haitian-American or users of intravenous drugs. A majority of patients with tuberculosis presented with fever and weight loss. These symptoms were seen in approximately 50 percent of the patients with nontuberculous mycobacteriosis. A distinct syndrome of dyspnea, chills, hemoptysis, and chest pain was seen in a significant minority of patients with nontuberculous mycobacteriosis. Lymphadenopathy was seen almost exclusively in patients with tuberculosis. Pulmonary sources (expectorated sputum or bronchoscopy specimens) were the most common source of diagnosis in both groups. Patients in both groups in whom the diagnosis was obtained from pulmonary sources frequently had negative chest x-ray films on presentation. Cavitary disease was absent from both groups.
Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Infecções por Mycobacterium não Tuberculosas/etiologia , Infecções por Mycobacterium/etiologia , Infecções Oportunistas/etiologia , Tuberculose Pulmonar/etiologia , Adulto , Fatores Etários , Broncoscopia , Feminino , Haiti/etnologia , Homossexualidade , Humanos , Masculino , Infecções por Mycobacterium não Tuberculosas/diagnóstico , Fatores de Risco , Escarro/microbiologia , Transtornos Relacionados ao Uso de Substâncias , Tuberculose Pulmonar/diagnóstico , Estados UnidosRESUMO
Production of cytotoxin and enterotoxin by Aeromonas strains obtained from stools of 50 children in Mexico and Texas and from blood of 9 children with sepsis was determined. Results were correlated with clinical features of infected children as well as with biochemical traits of Aeromonas strains. Cytotoxin was produced by 40 of 42 Aeromonas strains (95%) isolated from stools of children with diarrhea, by all 8 isolates from stools of well children, and by all 9 isolates from children with sepsis. There was no difference in the quantities (amount of cytotoxin per milligram of protein required to kill 50% of the cells) of cytotoxin produced and in clinical manifestations among the groups. None of the isolates produced a toxin that could be neutralized by antiserum raised against Shiga toxin produced by Shigella dysenteriae 1 60R. Heat-labile-like enterotoxin (LT) was produced by 26 of 42 stool isolates (62%), while only 1 of the 42 isolates (2%) produced enterotoxinlike activity in suckling mice; 65% of the cytotoxin-producing strains also produced an LT-like material. All strains from blood produced LT-like material, and 2 of 6 (33%) produced activity in suckling mice. All strains produced hemolysin; 37 of 57 (65%) were Voges-Proskauer positive; 27 of 57 (47%) were lysine decarboxylase positive by API 20E strips, none were positive for lysine decarboxylose production by lysin-iron agar slants at 24 h, but 17 of 54 (31%) were positive at 48 h. There was no correlation between biochemical reactions and enterotoxin or cytotoxin production. There appears to be no correlation between toxin production by Aeromonas spp. and gastroenteritis.