DETERMINATION OF SHIGELLA DYSENTERIAE 1ANDESCHERICHIA COLI O157:H7 ISOLATES TO PRODUCE SHIGATOXIN BY USING ELISA AND POLYMERASE CHAIN REACTION

	DETERMINATION OF SHIGELLA DYSENTERIAE 1ANDESCHERICHIA COLI O157:H7 ISOLATES TO PRODUCE SHIGATOXIN BY USING ELISA AND POLYMERASE CHAIN REACTION
Iraqi Journal of Biotechnology
Article 1, Volume 8, Issue 1, 2009, Pages 334-341
Abstract
One hundred fifty six stool specimens were collected from children under the age of six infected with diarrhea and attended the Children Protection Hospital in Baghdad during the months of Summer in the year 2005 for investigation and isolation of Shigelladysenteriae 1 and Escherichia coli O157:H7 bacteria. The bacterial isolates were identified depending on the morphological characteristics of the colonies, critical biochemical tests, api 20E strips beside latex agglutination test for each of S.dysenteriae1 and E.coli O157:H7. It was found that only one (0.6%) isolate belonged to S.dysenteriae1 and four (2.6%) belonged to E.coli O157:H7 from 156 stool specimens. Production of Stx was tested using ELISA technique. The test was done on 12 isolates (9 belonged to E.coli, 1 to S.dysenteriae1 and 2 belonged to S.sonnei). It was found that only 3 out of 12 isolates (25%) were producers for Stx; 2 out of 12 isolates (16.7%) belonged to E.coli O157:H7 and 1 (8.3%) to S.dysenteriae1, while the rest isolates (75%) were negative for Stx. Detection of stx gene in S.dysnerteriae1 and stx1, stx2 in E.coli O157:H7 isolates were done by polymerase chain reaction (PCR) technique by using promegaPCR Core System II. stx2 gene was detected only in two isolates of E.coli O157:H7 and non of them carried stx1 gene. stx gene was detected in S.dysenteriae1 isolate which used for its detection the same primer used for stx1 detection.
Keywords
Shigella dysenteriae; coli O; ELISA; PCR; Shigatoxins

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