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M Izhar

Publications and source records attributed to M Izhar.

22 records · Page 2Linked to original sources

An in vivo model for studying adherence of intestinal pathogens.

A new method for preparing an isolated colonic loop in a living rabbit is described. The loop with its intact neurovascular supply can be used as as a "living test tube" to study the adherence of microorganisms to intestinal mucosa. Moreover, the clear colonic mucus produced by the loop can be used to study its physiochemical nature and protecting properties in health and disease.

Adhesiveness↗

Bacterial adherence to surgical sutures. A possible factor in suture induced infection.

Surgical sutures are known to potentiate the development of wound infection. The purpose of this study was to investigate whether the capability of bacteria to adhere to various types of sutures has a significant effect on their ability to cause infections. Bacterial adherence to sutures was quantitatively measured using radiolabeled bacteria. In vitro adherence assays revealed remarkable variations in the affinity of bacteria to the various sutures: nylon bound the least bacteria while bacterial adherence to braided sutures (silk, Ti-cron, Dexon) was five to eight folds higher. The degree of infection obtained in mice in the presence of different sutures nicely correlated with their adherence properties. The different removal rate of adherent bacteria (glutaraldehyde-fixed) from various sutures by the tissue factors in mice supports the hypothesis that bacterial adherence to suture materials plays a significant role in the induction of surgical infection. Our observation points out at the need for careful suture selection in contaminated wounds. The adherence properties of sutures should be considered in any future surgical suture design.

Animals↗

Immunity induced by live attenuated Salmonella vaccines.

Studies on the degree and specificity of protection conferred by immunization with aroA salmonella live vaccines in BALB/c mice are described. Animals were immunized i.v. and challenged orally 3 months later to ensure that the vaccine had been cleared from the tissues. Vaccination with Salmonella typhimurium aroA SL3261 conferred very good protection against virulent S. typhimurium C5 (over 10,000 x LD50). The specificity of cross protection was studied using S. typhimurium, Salmonella enteritidis and Salmonella dublin for vaccination and challenge, including challenge with variants of S. typhimurium and S. enteritidis of similar virulence which differed in the main LPS (lipopolysaccharide) antigen (0-4 or 0-9). S. typhimurium SL3261 gave very good protection against S. typhimurium C5 (0-4), but no protection against S. enteritidis Se795 (0-9). However, challenge with strains differing in the main 0 antigens showed that, although protection was generally better to strains expressing the same LPS type as the vaccine, specificity of protection was determined more by the background (S. typhimurium or S. enteritidis) of the parent strain used for the challenge than by 0 factors 4 or 9, suggesting that other factors could be involved. The nature of the antigen(s) responsible for protection in this model is unclear, but it would not appear to be the main 0-specific antigen. An S. enteritidis Se795 aroA vaccine was far less effective than S. typhimurium SL3261; it conferred good protection against the homologous wild type at 2 weeks post-vaccination, but far less at three months (approx 10-200 x LD50). This was unexpected, as the persistence of the S. enteritidis vaccine in the liver and spleen was similar to that of S. typhimurium SL3261, and the S. enteritidis and S. typhimurium challenge strains were of similar virulence. An S. dublin aroA vaccine conferred similar protection against wild type S. dublin (approx 300 x LD50).

Animals↗