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Abstract

Objective—To determine whether an inactivated culture of a microcin-producing avian Escherichia coli was capable of killing Salmonella isolates from reptiles in an in vitro test system.

Sample Population—57 Salmonella isolate from reptiles.

Procedure—A wild-type avian E coli electrotransformed with a plasmid coding for the production of microcin 24 was tested in an in vitro microassay system for its ability to kill 57 Salmonella spp isolated from reptiles. The reptile population included snakes, iguana, frilled lizards, turtles, other lizards, and unspecified reptiles.

Results—44 of the Salmonella isolates were inhibited strongly, compared with the in vitro assay controls; 12 had weak inhibition, and 1 was not inhibited by the microcin-producing E coli. Thirteen of the 57 isolates had resistance to at least 1 antibiotic, primarily streptomycin. There were 9 O serogroups identified in the 57 isolates, with serogroup H being the most prevalent (18 to 57).

Conclusion and Clinical Relevance—Antibiotics are not recommended to eliminate Salmonella organisms from reptiles because of the development of antibiotic resistance. Further studies are necessary to determine whether the use of microcin-producing bacteria will be effective in controlling Salmonella infections in companion reptiles. (Am J Vet Res 2001;62:1399–1401)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To test the hypothesis that feedlot cattle with acute interstitial pneumonia (AIP) have bacterial infection of the lung or liver and concurrent bovine respiratory syncytial virus (BRSV) infection significantly more often than pen mates without AIP.

Animals—39 feedlot cattle with signs consistent with AIP and no history of treatment with antimicrobials and 32 healthy control cattle from the same pens.

Procedure—Lung and liver specimens were obtained postmortem for bacterial or mycoplasmal culture and histologic examination; lung tissue was assessed for BRSV infection immunohistochemically.

Results—Among affected cattle, 26 had AIP confirmed histologically. Lung tissue from 11 cattle with AIP yielded microbial respiratory tract pathogens on culture; tissues from control animals yielded no microbial growth. In 4 cattle with AIP and 2 control animals, liver abscesses were detected; bacteria were isolated from abscessed tissue in 3 and 1 of those animals, respectively. Immunohistochemically, 9 cattle with AIP and no control animals were BRSV-positive. Histologically, 9 AIP-affected cattle had only acute alveolar damage with exudation, and the other 17 had acute exudation with type II pneumocyte hyperplasia. No lesions of AIP were detected in control animals. Only 4 AIP-affected cattle had bacterial infection of the lung with concurrent BRSV infection.

Conclusions and Clinical Relevance—Results indicated that microbial respiratory tract pathogens are more common in cattle with AIP than in healthy pen mates. Control of bacterial pneumonia late in the feeding period may reduce the incidence of AIP at feedlots where AIP is a problem. (Am J Vet Res 2004;65:1525–1532)

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in American Journal of Veterinary Research