Invasiveness--an indicator of differentiation of virulent and non virulent isolates of Yersinia enterocolitica
Lal, M.
Indian Journal of Medical Microbiology 23(1): 69-70
2005
ISSN/ISBN: 0255-0857 PMID: 15928432 Document Number: 590659
This study assessed the effectiveness of Sereny test in demonstrating the epithelial invasiveness of 12 Y. enterocolitica isolates. Guineapigs weighing about 400 g were injected with iron dextran (50 mg) intraperitoneally (i.p.) on the first day, and desferal (50 mg) i.p. on the second day preceding bacterial inoculation of the right eye to increase their susceptibility to infection. The right eye of another group of guineapigs was inoculated with Shigella dysenteriae and served as a positive control. The uninoculated left eye of each animal served as a negative control. Animals were examined daily for 5 to 7 days for evidence of conjunctivitis. Only one isolate caused definite conjunctivitis, while 6 isolates caused mild conjunctivitis. Five isolates did not cause conjunctivitis, which might be due to the absence of a plasmid in these isolates. Sereny-positive isolates were virulent when tested in mice, and caused diarrhoea and death. It is suggested that the invasiveness of Y.enterocolitica is not dependent on plasmid. Invasiveness test may contribute to the diagnosis of invasive Y. enterocolitica as a cause of exudative diarrhoea.