Comparison of rapid methods for detection of heat-labile (LT) and heat-stable (ST) enterotoxin in Escherichia coli.

Oxoid VET-RPLA, ST-EIA and Pharmacia Phadebact ETEC-LT enterotoxin tests were compared to find a simple but reliable method for detecting enterotoxigenic Escherichia coli (ETEC) in Hungary. In the Oxoid tests, all six reference LT- or ST-producing strains, except one ST-producer, gave positive results. Of 11 reference porcine enterotoxigenic strains, all four LT-producers gave positive reactions for LT but three of 10 ST-producers gave negative reactions for ST. Thirteen of 50 strains from culture collections of H. Steinrück (Germany) were LT+ and nine of 33 were ST+. When 31 isolates were tested simultaneously with the Oxoid and the Pharmacia LT tests, 12 strains were LT+ by the Oxoid LT test but by the Phadebact LT test only seven of these strains were LT+ and, of the remainder, three gave uncertain results and two gave negative results. Of 69 porcine strains, seven were LT+ and three ST+. Of 901 human strains isolated in Hungary, 10 were LT+ and one of 24 tested was ST+. In two cases, ETEC strains were isolated from contacts of travellers returning from Mongolia and Bangladesh. Results of comparative studies with reference strains corresponded well to those of the classical toxin detection tests. The Oxoid test was rapid, sensitive, specific and easy to perform and is recommended for use in screening ETEC isolates.

Yersinia enterocolitica infection of animals and human contacts.

Infective animal sources and persons in contact with animals were investigated for Yersinia enteroclotica. The 68 isolates from 3115 animals belonged to four serogroups. The most frequent was serogroup O3 (62 strains) found mainly in pigs (41 strains). The same serogroup was isolated from dogs (9 strains), cats (6 strains) and from other animals (6 strains). A total of 556 animals living in the Budapest Zoo were examined. Y. enterocolitica was isolated from the faecal specimens of one chimpanzee and one gibbon. Using the Widal-type agglutination, out of sera of 877 persons in contact with animals, 4.56% were positive with antigens O3 and O9, compared to 0.33% in healthy controls. The study indicates that beside the occasional role of other animal species, pigs should be regarded as the main source of human enteric yersinosis.