University of Khartoum

Physiological Attributes of Cold-Shocked Escherichia Coli Salmonella sp.p, Staphylococcus Aureus and Pasteurella Multocida Type B

Physiological Attributes of Cold-Shocked Escherichia Coli Salmonella sp.p, Staphylococcus Aureus and Pasteurella Multocida Type B

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Title: Physiological Attributes of Cold-Shocked Escherichia Coli Salmonella sp.p, Staphylococcus Aureus and Pasteurella Multocida Type B
Author: Mubarak Mohmmed Ibrahim, Nagla
Abstract: Injured bacteria may be difficult to detect because they fail to grow on selective media normaly used for their isolation. However, under suitable conditions injured bacteria can repair cellular damage and recover all their normal properties including virulence. This study was conducted to observe some properties of selected cold- shocked bacteria and that included viable count of growth on selective and non- selective media before and after shock, release of ultra violet absorbing materials at 280 n.m and pathogenecity. The bacteria studied included Escherichia coli, Salmonella sp.p, Staphylococcus aureus andPasteurella multocida type B.The first three organisms were supplied by the department of microbiology- faculty of veterinary medicine - University ofKhartoum. The fourth organism was supplied by the biological products department - central veterinary research laboratories center, Soba.The selective media used were MacConkey , s agar for E.coli and Salmonella sp.p, Baird- Parker medium for Staph.aureus and Pasteurellamedium for Pasteurella multocida type B. The temperature used for shocking was –20˚C (deep freezer) for 24 hours. Five rabbits of local breeds were used to study the pathogenecity of injured Pasteurella multocida type B. The sensitivity of the organisms to freezing was variable; Staph.aureus was the most sensitive with 72.9% dead cells, 11% injured cells and 16.1% of uninjuredcells followed by Salmonella spp, which showed 61% dead cells,18.5% injured cells and 20.5% uninjured cells and then E.coli which showed 55.4% dead cells ,14.8%injured cells and 29.8% uninjured cells. Pasteurella multocida type B, it showed great sensitivity to freezing as it showed no colonies on the selective media but showed uncountable colonies on non-selective media. Four rabbits injected with injured cells of Pasteurella multocida type B, died in 24 hours, whereas the fifth rabbit which was injected with dead cells(did not grow on the non- selective medium) did not die even after five days. The reading of the release of u.v absorbing materials by spectrophotometer at 280 n.m revealed high concentration of this materials released by Pasteurella multocida type B andless concentrations released by the three other organisms
URI: http://khartoumspace.uofk.edu/handle/123456789/9333
Date: 2015-04-23


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