RESUMO
This study aimed to evaluate the protective function of probiotics against Shigella sonnei pathogenicity. For this purpose, 400 zebrafish were divided into four groups with two replications: (T1): receiving Lacticaseibacillus casei for 27 days, (T2): receiving L. casei for 27 days followed by 72 hr exposure to S. sonnei, (T3): receiving basal diet for 27 days followed by 72 hr exposure to S. sonnei, and control group (C): receiving basal diet without exposure to the pathogen. According to the results, feeding with L. casei for 27 days reduced the interleukin-8 (IL-8) expression significantly (P<0.05). The results showed a decrease in IL-8 expression in the group exposed to the pathogen and fed with the probiotic compared to the group only fed with the basal diet (P<0.05). Considering the role of IL-8 as a pro-inflammatory cytokine, our results indicated that feeding with L. casei could modulate inflammatory responses.
Este estudo teve como objetivo avaliar a função protetora dos probióticos contra a patogenicidade Shigella sonnei. Para este fim, 400 zebrafish foram divididos em quatro grupos com duas réplicas: (T1): recebendo Lacticaseibacillus casei por 27 dias, (T2): recebendo L. casei por 27 dias seguido por 72 horas de exposição a S. sonnei, (T3): recebendo dieta basal por 27 dias seguido por 72 horas de exposição a S. sonnei, e grupo controle (C): recebendo dieta basal sem exposição ao patógeno. De acordo com os resultados, a alimentação com L. casei por 27 dias reduziu significativamente a expressão da interleucina-8 (IL-8) (P<0,05). Os resultados mostraram uma diminuição na expressão de IL-8 no grupo exposto ao patógeno e alimentado com o probiótico em comparação com o grupo alimentado apenas com a dieta basal (P<0,05). Considerando o papel da IL-8 como uma citocina pró-inflamatória, nossos resultados indicaram que a alimentação com L. casei poderia modular as respostas inflamatórias.
Assuntos
Animais , Shigella sonnei/patogenicidade , Peixe-Zebra , Lacticaseibacillus casei , Interleucina-8 , Ração AnimalRESUMO
Molecular characterization of virulence and antimicrobial resistance profiles were determined for Shigella species isolated from children with diarrhea in Fortaleza, Brazil. Fecal specimens were collected along with socioeconomic and clinical data from children with moderate to severe diarrhea requiring emergency care. Shigella spp. were isolated by standard microbiological techniques, and we developed 4 multiplex polymerase chain reaction assays to detect 16 virulence-related genes (VRGs). Antimicrobial susceptibility tests were performed using disk diffusion assays. S. flexneri and S. sonnei were the predominant serogroups. S. flexneri was associated with low monthly incomes; more severe disease; higher number of VRGs; and presence of pic, set, and sepA genes. The SepA gene was associated with more intense abdominal pain. S. flexneri was correlated with resistance to ampicillin and chloramphenicol, whereas S. sonnei was associated with resistance to azithromycin. Strains harboring higher numbers of VRGs were associated with resistance to more antimicrobials. We highlight the correlation between presence of S. flexneri and sepA, and increased virulence and suggest a link to socioeconomic change in northeastern Brazil. Additionally, antimicrobial resistance was associated with serogroup specificity in Shigella spp. and increased bacterial VRGs.
Assuntos
Antibacterianos/farmacologia , Disenteria Bacilar/microbiologia , Shigella flexneri/genética , Shigella flexneri/patogenicidade , Shigella sonnei/genética , Shigella sonnei/patogenicidade , Ampicilina/farmacologia , Azitromicina/farmacologia , Proteínas de Bactérias/genética , Brasil , Cloranfenicol/farmacologia , Testes de Sensibilidade a Antimicrobianos por Disco-Difusão , Farmacorresistência Bacteriana , Disenteria Bacilar/tratamento farmacológico , Humanos , Reação em Cadeia da Polimerase Multiplex/métodos , Serina Proteases/genética , Shigella flexneri/efeitos dos fármacos , Shigella flexneri/isolamento & purificação , Shigella sonnei/efeitos dos fármacos , Shigella sonnei/isolamento & purificação , Virulência/genéticaRESUMO
The mass profiles of cell-free extracts of 180 commensal and pathogenic strains of Escherichia coli were determined by MALDI-TOF mass spectrometry (MS). While some peaks were highly conserved in all E. coli, several peaks occurred only in some strains, showing heterogeneity among them. We did not detect strain-specific peaks for any of the E. coli categories tested. However, review of the fully conserved and the variable peaks suggested that MALDI-TOF MS has the potential to distinguish commensal and uropathogenic E. coli strains. Additionally, eight Shigella sonnei isolates were tested and found to be indistinguishable from E. coli by MALDI-TOF MS under the test conditions.
Assuntos
Sistema Livre de Células , Escherichia coli/química , Shigella sonnei/classificação , Escherichia coli/classificação , Escherichia coli/patogenicidade , Humanos , Shigella sonnei/química , Shigella sonnei/patogenicidade , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
BACKGROUND: We evaluated a dipstick test for rapid detection of Shigella sonnei on bacterial colonies, directly on stools and from rectal swabs because in actual field situations, most pathologic specimens for diagnosis correspond to stool samples or rectal swabs. METHODOLOGY/PRINCIPAL FINDINGS: The test is based on the detection of S. sonnei lipopolysaccharide (LPS) O-side chains using phase I-specific monoclonal antibodies coupled to gold particles, and displayed on a one-step immunochromatographic dipstick. A concentration as low as 5 ng/ml of LPS was detected in distilled water and in reconstituted stools in 6 minutes. This is the optimal time for lecture to avoid errors of interpretation. In distilled water and in reconstituted stools, an unequivocal positive reaction was obtained with 4 x 10(6) CFU/ml of S. sonnei. The specificity was 100% when tested with a battery of Shigella and different unrelated strains. When tested on 342 rectal swabs in Chile, specificity (281/295) was 95.3% (95% CI: 92.9% - 97.7%) and sensitivity (47/47) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 95.5 % of cases (328/342) in comparative studies. Positive and negative predictive values were 77% (95% CI: 65% - 86.5%) and 100% respectively. When tested on 219 stools in Chile, Vietnam, India and France, specificity (190/198) was 96% (95% CI 92%-98%) and sensitivity (21/21) was 100%. Stool cultures and the immunochromatographic test showed concordant results in 96.3 % of cases (211/219) in comparative studies. Positive and negative predictive values were 72.4% (95% CI 56.1%-88.6%) and 100 %, respectively. CONCLUSION: This one-step dipstick test performed well for diagnosis of S. sonnei both on stools and on rectal swabs. These data confirm a preliminary study done in Chile.
Assuntos
Diarreia/diagnóstico , Fezes/microbiologia , Reto/microbiologia , Shigella sonnei/patogenicidade , Diarreia/microbiologia , Humanos , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Shigella sonnei/isolamento & purificaçãoRESUMO
Shigella is a common agent of diarrhoea, a worldwide major health problem. The bacterium produces bacteriocins; however, the role of these substances as a virulence factor is completely unknown. With the aim to search for colicin production by Shigella sonnei, to evaluate the influence of culture conditions on bacteriocin expression, and to characterize the substance partially, 16 S. sonnei strains isolated from children with diarrhoea were tested for antagonism against members of the intestinal microbiota or agents of diarrhoea. Nine strains exhibited isoantagonism and heteroantagonism against S. flexneri and diarrhoeagenic Escherichia coli. Autoantagonism and antagonism against the intestinal microbiota were not detected. Culture medium and incubation conditions influenced antagonism expression. Antagonism resulting from bacteriophages, low pH, fatty acids, hydrogen peroxide, and chloroform was excluded. The activity of the intracellular fraction obtained with 75% ammonium sulphate was preserved at pH 1.0-11.0, and was found to be reduced by organic solvents and affected by high temperatures and proteases. The antagonistic spectrum and the in vitro conditions for better antagonism expression suggest that the role of colicin in S. sonnei virulence, if any, would be expressed prior to infection, and may regulate population density of enteropathogens by helping in organism transmission.
Assuntos
Bacteriocinas/biossíntese , Diarreia/microbiologia , Fezes/microbiologia , Shigella sonnei/patogenicidade , Doença Aguda , Criança , HumanosRESUMO
BACKGROUND: Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays. RESULTS: Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins. CONCLUSIONS: Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.
Assuntos
Aderência Bacteriana/efeitos dos fármacos , Proteínas do Leite/farmacologia , Shigella dysenteriae/patogenicidade , Shigella flexneri/patogenicidade , Shigella sonnei/patogenicidade , Anticorpos Antibacterianos/farmacologia , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Criança , Células HeLa , Humanos , Imunoglobulina A Secretora/imunologia , Lactoferrina/metabolismo , Ácido Periódico/farmacologia , Shigella dysenteriae/efeitos dos fármacos , Shigella dysenteriae/isolamento & purificação , Shigella flexneri/efeitos dos fármacos , Shigella flexneri/isolamento & purificação , Shigella sonnei/efeitos dos fármacos , Shigella sonnei/isolamento & purificaçãoRESUMO
Comenta-se nesta breve revisao a participacao e o significado de Shigella em processos de infeccao alimentar. Sao tambem abordados as caracteristicas do microrganismo, seus fatores de virulencia e determinancia genetica.Aspectos epidemiologicos da infeccao, bem como, condicoes de crescimento e metodos de deteccao em alimentos, sao tambem abordados
Assuntos
Humanos , Disenteria Bacilar/diagnóstico , Disenteria Bacilar/epidemiologia , Disenteria Bacilar/patologia , Disenteria Bacilar/prevenção & controle , Manipulação de Alimentos/métodos , Shigella boydii/crescimento & desenvolvimento , Shigella boydii/patogenicidade , Shigella dysenteriae/crescimento & desenvolvimento , Shigella dysenteriae/patogenicidade , Shigella flexneri/crescimento & desenvolvimento , Shigella flexneri/patogenicidade , Shigella sonnei/crescimento & desenvolvimento , Shigella sonnei/patogenicidade , Virulência , Contaminação de Alimentos/prevenção & controle , Higiene dos Alimentos , Indústria de Processamento de Alimentos/métodos , Indústria de Processamento de Alimentos , Infecções Bacterianas/transmissão , Intestinos/patologiaRESUMO
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
Se presenta un caso de diarrea por triple etiología (Shigella Campylobacter-criptosporidium) en una niña de 3 meses y medio de edad, quién ingresó al Hospital Nacional de Niños en mayo de 1984
Assuntos
Lactente , Humanos , Feminino , Diarreia Infantil/etiologia , Campylobacter fetus/patogenicidade , Cryptosporidium/patogenicidade , Shigella sonnei/patogenicidadeRESUMO
In a study of the findings on bacteriological investigation of infantile diarrhoea in British Guiana during a period of 14 months in 1858-1959, the agents were as follows: Shigella sonnei 38 percent, Shigella flexneri types 16 percent, Salmonella coeln 16 percent, Escherichia coli types 24 percent of 76 positive results. Death from diarrhoea represent some 22 percent of all deaths in infants aged one year and under (Summary)