 |
| About Bioline | All Journals | Testimonials | Membership | News |
|
||||||
|
||||||
Indian Journal of Medical Microbiology, Vol. 23, No. 1, January-March, 2005, pp. 69-70 Correspondence Invasiveness - An indicator of differentiation of virulent and non virulent isolates of Yersinia enterocolitica Lal M Department of Microbiology, Christian Medical College, Ludhiana - 141 008, Punjab Code Number: mb05020 Dear Editor, Yersinia enterocolitica, an emerging pathogen has been implicated as causative agent for a number of clinical manifestations predominantly diarrhoea. Invasiveness into epithelial cells is an important pathogenic mechanism of enteric bacteria, including strains of Shigella, Salmonella, Escherichia coli and Yersinia.[1] Clinically, the invasive bacteria are capable of producing dysentery like disease or exudative diarrhoea. Pathogenic Y.enterocolitica strains are characterized by their ability to adhere to and invade epithelial cells.[2] Demonstration of epithelial invasiveness of Enterobacteriacea can be done by Sereny test.[3] To assess the relative importance of Sereny test twelve isolates of Y.enterocolitica were tested by Sereny test to determine the virulence of these micro organisms. Guinea pigs weighing about 400g were injected 50mg of iron dextran intraperitoneally on first day and 50mg of desferal intraperitoneally on the second day preceding bacterial inoculation to increase susceptibility of the animals to infection. A volume of 25 µL containing 109 organisms were put into right conjunctival sac of a group of three guinea pigs for each isolate. Control animals were given culture of Shigella dysteriae as positive control, while the uninoculated left eye of each animal used in the test served as negative control. Animals were examined daily for 5 to 7 days for the evidence of conjunctivitis. One isolate produced definite, three mild and three minimum conjunctivitis while five isolates did not produce any conjunctivitis. Either absence or mild keratoconjunctivitis might be due to absence of plasmid in the isolates tested in this study. Sereny positive isolates were found to be virulent when tested in mice for diarrhoea and death. The observation is supported by Schiemann and Devenish[4] who suggested that invasiveness of Y.enterocolitica for HeLa cells was not dependent on plasmid. As for Y.enterocolitica, invasiveness test may contribute to the diagnosis of invasive Y.enterocolitica as a cause of exudative diarrhoea. REFERENCES
Copyright 2005 - Indian Journal of Medical Microbiology |
| |||||||||
