| dc.description.abstract | A variety of potential enteropathogenic micro-organisms could be
incriminated in 97,4% of acute cases of sporadic infantile gastroenteritis. Although multiple infections occured frequently,
enterotoxigenic Enterobacteriaceae (46,2%), rotavirus (43,6%),
enteropathogenic Escherichia coli serotipes (38,5%), Staphyl ococcus
aureus (15,4%), Salmonella species (5,1 %), Shigella species (5, 1%),
Candida albicans (2,6%), Candida krusei (2,6%), Pseudomonas
aeruginosa (2,6%), Bacillus cereus (2,6%) and hemolytic E.coli
were implicated as causitive agents. Unassociated enterotoxigenic
Enterobacteriaceae were more frequently isolated than others.
Choleragen-like labile toxins (LT), stable toxin (ST) or a
combination of both (ST+ LT) were shown to be produced by various
members of Enterobacteriaceae . The various toxins could be
demons t rated in 5 E. coli (LT), 4 E. coli (ST), 2 E. coli (ST+ LT),
5 Klebsiella pneumoniae (LT), 2 Enterobacter cloacae (LT),
Enterobacter aerogenes (LT) and 1 Proteus vulgaris (LT). Labile
toxins from the various gene ra induce mutually variable but high
level accumulation of intracellular cyclic adenosine 3' ,5'-monophosphate
(cAMP) of Chinese hams ter ovary Kl (CHO-Kl) cells . Induction of
cAMP is neutralised to high titre by antiserum to choleragen.
Pretreatment of the various labile toxins with GM1 ganglioside
or blocking of receptors on CHO-Kl cells by the B sub-unit of
choleragen similarly prevent the accumulation of cAMP. This
relationship with choleragen suggests a similar mechanisms of
diarrhoea induction.
The plasmid (Ent) mediated nature of enterotoxin syn thesis was
demonstrated for ST and- ST+ LT producing E. coli strains. These
determinants were transfered to non-enteropathogenic E. coli Kl2
strains by conjugation . Similarly co-transfer of Ent (ST+ LT) and
resistance determinants coding for sulphafurazole, ampicillin,
carbenicill in and tetracycline from enteropathogenic E. col i serotipe, 0128:K67:H27, to non-enteropathogenic E. coli K12 were
accomplished. These findings imply diagnostic and therapeutic
complications in the diagnosis and treatment of gastroenteritis.
Some toxin producers such as E. coli (ST), K. pneumoniae (LT),
Enterobacter (LT) species and P. vulgaris (LT) do not behave as
typical faecal coliforms as judged by tests used for water quality
control. This, as well as the isolation in significant quantities
of enterotoxigenic E. coli (LT) and K. pneumoniae (LT) from water
and sewage, may indicate a pos s ible source of enterotoxigenic infections. These findings call for a review of the status of
indicator organisms and of health standards for water for human
consumption. | en_US |
