Placental and colostral transfer of antibodies reactive with enteropathogenic Escherichia coli intimins α, ß, or γ / Transferência placentária e colostral de anticorpos reativos a Escherichia coli enteropatogênica com expressão das intiminas α, ß, or γ

Abstract Objective: Intimins are protein adhesins of enteropathogenic Escherichia coli and enterohemorrhagic E. coli capable of inducing attachment and effacement lesions in enterocytes. Anti-intimin antibodies are important for the protection from enteropathogenic E. coli and enterohemorrhagic E. coli infections because these antibodies inhibit bacterial adhesion and impair the initial step of the pathogenesis. We studied the transfer of maternal anti-intimin antibodies from healthy Brazilian mothers to their newborns through the placenta and colostrum. Methods: Serum immunoglobulin G and secretory immunoglobulin A antibodies against conserved and variable regions of intimins α, β, and γ were analyzed using an enzyme linked-immunosorbent assay in the blood and colostrum from 45 healthy women as well as cord blood serum samples from their newborns. Results: The concentrations of antibodies reactive with α intimin were significantly lower than those of anti-γ and anti-conserved intimin antibodies in the colostrum samples. IgG serum antibodies reactive with all the subtypes of intimins were transferred to the newborns, but the concentrations of anti-conserved intimin serum antibodies were significantly higher in mothers and newborns than concentrations of antibodies against variable regions. The patterns of IgG transfer from mothers to newborns were similar for all anti-intimin antibodies. These values are similar to the percentage transference of total IgG. Conclusions: Anti-intimin antibodies are transferred from mothers to newborns through the placenta, and reinforce the protection provided by breastfeeding against diarrheagenic E. coli infections.

Resumo Objetivo: As intiminas são adesinas proteicas de Escherichia coli enteropatogênicas (EPEC) e enterro-hemorrágicas (EHEC) capazes de induzir as lesões attaching and effacing nos enterócitos. Anticorpos anti-intiminas são importantes para a proteção contra infecções por EPEC e EHEC porque esses anticorpos inibem a adesão bacteriana e impedem o passo inicial do mecanismo patogênico dessas bactérias. Nós estudamos a transferência de anticorpos maternos anti-intiminas de mães brasileiras saudáveis para os seus recém-nascidos através da placenta e do colostro. Métodos: Anticorpos séricos da classe IgG e secretórios da classe IgA (SIgA) reativos com as porções conservada (cons) e variáveis das intiminas α (vα), β (vβ) e γ (vγ) foram analisados pelo teste de ELISA no sangue e no colostro de 45 parturientes saudáveis e no sangue de cordão umbilical dos seus respectivos recém-nascidos. Resultados: As concentrações de anticorpos reativos com intimina vα foram significativamente mais baixas que as dos anticorpos anti-vγ e anti-cons nas amostras de colostro. Anticorpos IgG séricos reativos com todas as intiminas foram transferidos para os recém-nascidos, mas as concentrações de anti-cons foram significativamente mais altas tanto nas mães como nos recém-nascidos do que os anticorpos reativos com as regiões variáveis das intiminas. O padrão de transferência de IgG das mães para os recém-nascidos foi muito semelhante para todos os anticorpos anti-intiminas. Os valores de porcentagem de transferência foram semelhantes à transferência de IgG total. Conclusões: Anticorpos anti-intimina são transferidos das mães para os recém-nascidos pela placenta e corroboram a proteção contra infecções por Escherichia coli diarreiogênicas (DEC) conferida pelo aleitamento materno.

Action of phosphorylated mannanoligosaccharides on immune and hematological responses and fecal consistency of dogs experimentally infected with enteropathogenic Escherichia coli strains

The therapeutic action of phosphorylated mannanoligosaccharides (MOS) was investigated regarding its prebiotic activity on enteropathogenic Escherichia coli (EPEC). Diarrhea was induced in dogs by experimental infection with EPEC strains. Then MOS was supplied once a day, in water for 20 days. Immunological (IgA and IgG), hematological (lymphocytes, neutrophils and monocytes) and bacteriological variables (PCR detection of the eae gene of EPEC recovered from stool culture), as well as occurrence of diarrhea were evaluated. All strains caused diarrhea at 24, 48 and 72 h after infection. PCR results indicated that E. coli isolated from stool culture of all infected animals had the eae gene. There was no significant difference among groups as to number of blood cells in the hemogram and IgA and IgG production. MOS was effective in recovering of EPEC-infected dogs since prebiotic-treated animals recovered more rapidly from infection than untreated ones (p < 0.05). This is an important finding since diarrhea causes intense dehydration and nutrient loss. The use of prebiotics for humans and other animals with diarrhea can be an alternative for the treatment and prophylaxis of EPEC infections.

Occurrence and molecular characterization of enteropathogenic Escherichia coli serotypes isolated from children with diarrhoea in Najaf, Iraq.

Purpose: Enteropathogenic Escherichia coli (EPEC) are among the most important pathogens infecting children worldwide and are one of the main causes of diarrhoea. The study was carried out to investigate the occurrence of EPEC as a cause of infectious diarrhoea in children younger than 2 years of age and characterize their virulence genes. Materials and Methods: During the study period, a total of 656 faecal specimens from children with diarrhoea and 54 from healthy children were analyzed. E. coli isolates were serotypically identified with EPEC polyvalent and monovalent antisera. The isolated EPEC were examined for the presence of the attaching and effacing (eaeA), bundle-forming pilus (bfpA), Shiga like toxins (stx1 and stx2 ), enterohaemorrhagic E. coli enterohaemolysin (EHEC hlyA) and EPEC adherence factor (EAF) genes by the PCR assay. Results: The study has shown that 22 (3.4%) had diarrhoea due to EPEC, while no EPEC isolates were detected in asymptomatic children. The highest number of the EPEC isolated belonging to polyvalent 2. The primers encoding virulence genes were subjected to all the EPEC isolates. Only 9.1%, 27.3%, and 9.1% isolates gave positive re sults with intimin (eaeA), bfbA and (EAF) genes, respectively. None of the isolates were positive for stx 1, stx 2, and hlyA genes. Typical EPEC (eaeA +, bfpA +) was diagnosed in two isolates, while, atypical EPEC was manifested in four isolates. Conclusions: According to the results, the frequency of EPEC isolates in Najaf was lower than what has been suspected and the investigation including the use of molecular technique and serotyping, are necessary to allow precise identification and epidemiological study of these pathogens.

Anticorpos anti-intiminas α, β, e γ de Escherichia coli em soros e colostros de adultos saudáveis da Grande São Paulo / Antibodies reactive with α, β,and γ intimins of Escherichia coli in serum and colostrum samples of healthy adults living in São Paulo, Brazil

A diarréia é um importante problema de saúde pública no mundo inteiro e a Escherichía coli é um dos mais freqüentes microorganismos causadores desta doença. A Escherichia coli enteropatogênica (EPEC), um dos principais agentes etiológicos das diarréias infantis no nosso país, é genética e fenotipicamente relacionada com a E. colí enterohemorrágica (EHEC) que além de provocar diarréia é responsável por complicações como síndrome hemolítica urêmica (HUS) e colite hemorrágica (HC). Embora a EHEC seja considerada emergente pela OMS, no Brasil poucos casos de complicações como HUS e HC foram reportados. O mecanismo de patogenicidade comum entre EPEC e EHEC é conhecido como a lesão "attaching and effacing" nos microvilos do enterócito. Esta lesão é mediada por um conjunto de fatores de virulência, dentre eles a intimina. A intimina é uma proteína de membrana externa, responsável pelo íntimo contato da bactéria com o enterócito, possui uma região N-terminal que é altamente conservada e uma região C-terminal que é variável. De acordo com a região variável, existem vários subtipos de intimina, dentre eles as intiminas , α, β e γ...