Enterotoxigenic and necrotizing Escherichia coli in human diarrhoea in Spain

Blanco, Jorge; González, Enrique A.; Espinosa, Patricia; Blanco, Miguel; Garabal, J.I.; Alonso, M. P.

doi:10.1007/bf00146375

Cited by 18 publications

(14 citation statements)

References 29 publications

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“…Diarrhoeal diseases due to the virulent strains have been extensively reported and account for a substantial degree of morbidity and mortality in different age groups (El-Sheikh and El-Assouli, 2001;Galane and Le Roux, 2001). Virulent strains of E. coli include enteropathogenic E. coli (EPEC), enteroinvasive E. coli (EIEC), enterohaemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), and enterotoxigenic E. coli (ETEC) (Giron et al, 1991;Falbo et al, 1992;Blanco et al, 1992;Chan et al, 1994;Levine, 1987). The clinico-epidemiological patterns of the virulent strains vary, and association with travellers' diarrhoea, extra-intestinal infections, acute, chronic or persistent diarrhoea are known (Falbo et al, 1992;Chan et al, 1994).…”

Section: Introductionmentioning

confidence: 99%

Gene encoding virulence markers among <i>Escherichia coli</i> isolates from diarrhoeic stool samples and river sources in rural Venda communities of South Africa

Obi¹,

Green²,

Bessong³

et al. 2004

WSA

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River water sources and diarrhoeic stools of residents in the Venda Region, Limpopo Province of South Africa were analysed for the prevalence of Escherichia coli (E. coli) and the presence of virulence genes among the isolates. A control group of 100 nondiarrhoeic stool samples was included. Escherichia coli was isolated and identified by standard cultural and biochemical methods. Pathogenicity of environmental and human isolates was determined by amplification of genes associated with virulence of E. coli, using specific primers.Of a total of 228 water and river sediment samples screened, E. coli was recovered from 200 (87.7%), and 135 (67.5%) of these had one or more genes associated with pathogenicity. The highest frequency of isolation of pathogenic strains was found in Ritavi River water and sediment (80.6%), followed by Lotanyanda River (76.9%), and the least (45.8%) in Nzhelele River 2. Escherichia coli was recovered from all of the 252 diarrhoeic stools tested (100%), and 119 (47.28%) of these had one or more genes associated with pathogenicity. The frequency of isolation of potential pathogenic E. coli from humans was highly significant (t = 6.3; pd•0.01) in comparison to water isolates. Cytotoxic necrotizing Factor 1 (cnf1) and cytotoxic necrotising Factor 2 (cnf2) coding for necrotoxigenic E. coli (NEC); bundle-forming pilus (bfpA) and enteropathogenic attachment and effacement (eaeA) coding for enteropathogenic E. coli (EPEC), occurred in 35% and 34% respectively of river isolates. Heat-stable (ST) and heat-labile (LT) toxin genes coding for enterotoxigenic (ETEC) and Shiga-like toxin 1 (Stx1) and Shiga-like toxin 2 (Stx2) coding for Shiga-like toxin-producing E. coli (STEC) were not encountered in the river isolates. Isolates from stool samples had 21.8% and 12.6% of EPEC and NEC strains respectively; while enterotoxigenic (ETEC), Shiga-like toxin-producing (STEC) and enteroaggregative E. coli (EAEC) had a prevalence of 5%, 5.8% and 5.8% respectively. One human isolate possessed stx2 and eaeA indicating E. coli O157: H7. No genes associated with pathogenicity were observed in human non-diarrhoeic stool isolates. Results have revealed a possibility of a recycling of pathogenic E. coli strains, particularly the EPEC and NEC strains, between the water sources and the local population.

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Section: Introductionmentioning

confidence: 99%

Gene encoding virulence markers among <i>Escherichia coli</i> isolates from diarrhoeic stool samples and river sources in rural Venda communities of South Africa

Obi¹,

Green²,

Bessong³

et al. 2004

WSA

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“…NTEC were associated with human extraintesti-nal infections [8][9][10][11][12][13], and isolated from calves with diarrhoea or septicaemia [14][15][16][17]. It has also been suggested that NTEC might be opportunistic pathogens causing diarrhoeal diseases in humans [18][19][20]. However, we have recently found that NTEC strains can be isolated from the faeces of a representative percentage of healthy children and calves; consequently, the association of NTEC strains with human and animal diarrhoea must be carefully investigated (Doctoral thesis of M. Blanco: Entcrotoxigenic, necrotizing and verotoxigenic E.coli of human and bovine origin.…”

Section: Introductionmentioning

confidence: 99%

Serogroups of Escherichia coli strains producing cytotoxic necrotizing factors CNF1 and CNF2

Blanco

Alonso

et al. 1992

FEMS Microbiology Letters

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The serogroups of 396 necrotizing Escherichia coli of human and bovine origin isolated in Spain between 1979 and 1991 have been determined. The 270 cytotoxic necrotizing factor strains belonged to 22 different O serogroups; however, 84% (226 of 270) were of one of seven serogroups (O2, O4, O6, O14, O22, O75 and O83). Although necrotizing E. coli producing cytotoxic necrotizing factor 2 belonged to 28 different serogroups, only six of them (O1, O3, O15, O55, O88 and O123) accounted for 60% (76 of 126) of cytotoxic necrotizing factor 2 strains. Furthermore, only 3% (4 of 126) of cytotoxic necrotizing factor 2 strains belonged to serogroups most common among strains producing cytotoxic necrotizing factor 1. The majority of necrotizing E. coli producing cytotoxic necrotizing factor 1 were obtained from human extraintestinal infections, whereas cytotoxic necrotizing factor 2 strains were isolated from stools of healthy and diarrhoeic calves.

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“…Alpha-hemolytic E. coli strains have been associated with human enteric disease, especially among young children (8,(10)(11)(12)(20)(21)(22), and the related enterohemolysin of E. coli O157 (35) appears to be involved in enteric disease. There has, however, been no large prospective case-controlled epidemio-logic study of the association of alpha-hemolysin with human diarrhea.…”

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confidence: 99%

“…Similar to alpha-hemolysin, the role of CNF1 in diarrhea remains unclear. CNF1-producing strains have been isolated from diarrheal stools and have been associated with several outbreaks in humans (8,10) and animals (13,33,44). Unfortunately, no large, prospective, case-controlled studies have been performed, and the best evidence for the pathogenicity of CNF1-toxigenic isolates is the marked virulence in piglet challenge experiments (45), outlined above.…”

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confidence: 99%

Characterization of the Roles of Hemolysin and Other Toxins in Enteropathy Caused by Alpha-Hemolytic Escherichia coli Linked to Human Diarrhea

et al. 1998

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Escherichia coli strains producing alpha-hemolysin have been associated with diarrhea in several studies, but it has not been clearly demonstrated that these strains are enteropathogens or that alpha-hemolysin is an enteric virulence factor. Such strains are generally regarded as avirulent commensals. We examined a collection of diarrhea-associated hemolytic E. coli (DHEC) strains for virulence factors. No strain produced classic enterotoxins, but they all produced an alpha-hemolysin that was indistinguishable from that of uropathogenic E. coli strains. DHEC strains also produced other toxins including cytotoxic necrotizing factor 1 (CNF1) and novel toxins, including a cell-detaching cytotoxin and a toxin that causes HeLa cell elongation. DHEC strains were enteropathogenic in the RITARD (reversible intestinal tie adult rabbit diarrhea) model of diarrhea, causing characteristic enteropathies, including inflammation, necrosis, and colonic cell hyperplasia in both small and large intestines. Alpha-hemolysin appeared to be a major virulence factor in this model since it conferred virulence to nonpathogenic E. colistrains. Other virulence factors also appear to be contributing to virulence. These findings support the epidemiologic link to diarrhea and suggest that further research into the role of DHEC and alpha-hemolysin in enteric disease is warranted.

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Enterotoxigenic and necrotizing Escherichia coli in human diarrhoea in Spain

Cited by 18 publications

References 29 publications

Gene encoding virulence markers among <i>Escherichia coli</i> isolates from diarrhoeic stool samples and river sources in rural Venda communities of South Africa

Gene encoding virulence markers among <i>Escherichia coli</i> isolates from diarrhoeic stool samples and river sources in rural Venda communities of South Africa

Serogroups of Escherichia coli strains producing cytotoxic necrotizing factors CNF1 and CNF2

Characterization of the Roles of Hemolysin and Other Toxins in Enteropathy Caused by Alpha-Hemolytic Escherichia coli Linked to Human Diarrhea

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