Journal article
Defective bacterial clearance is responsible for the enhanced lung pathology characteristic of Mannheimia haemolytica pneumonia in bighorn sheep
Veterinary microbiology, Vol.153(3), pp.332-338
2011
Handle:
https://hdl.handle.net/2376/109439
PMID: 21742446
Abstract
The molecular and cellular basis for the enhanced lung pathology and mortality caused by
Mannheimia haemolytica in bighorn sheep (BHS,
Ovis canadenesis), in comparison to domestic sheep (DS,
Ovis aries), is not clear. Polymorphonuclear leukocytes (PMNs) of BHS are four- to eight-fold more susceptible to
M. haemolytica leukotoxin-induced cytolysis, which is likely to reduce the number of functional phagocytes in the lung. We hypothesized that enhanced lung pathology is due to defective clearance of
M. haemolytica from the lungs of BHS. To test this hypothesis,
M. haemolytica (1
×
10
7 colony forming units [cfu]) were inoculated intra-tracheally into three groups each of BHS and DS, which were euthanized and necropsied at 4, 12, and 18
h post-inoculation (hpi). Bacterial and leukocyte counts were performed on broncho-alveolar lavage fluid (BALF) collected at necropsy. BALF from BHS euthanized at 4 and 12
hpi contained a significantly higher number of
M. haemolytica than that from DS. More importantly, DS did not have any bacteria in BALF at 18
hpi, while the BHS still had significant numbers. As expected, the BHS did exhibit more extensive lung lesions at 12 and 18
hpi when compared to DS. At 18
hpi, necrotic PMNs were observed in the lesional lung tissues of BHS, but not DS. Furthermore, BALF from BHS had significantly lower titers of antibodies to Lkt and surface antigens of
M. haemolytica, than that of DS. These findings suggest that the enhanced pathology in BHS lungs is due to defective clearance of
M. haemolytica from the lungs.
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Details
- Title
- Defective bacterial clearance is responsible for the enhanced lung pathology characteristic of Mannheimia haemolytica pneumonia in bighorn sheep
- Creators
- Renuka Subramaniam - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USACaroline N Herndon - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USASudarvili Shanthalingam - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USARohana P Dassanayake - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USAJegarubee Bavananthasivam - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USAKathleen A Potter - Washington Animal Disease Diagnostic Laboratory, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USADonald P Knowles - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USAWilliam J Foreyt - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USASubramaniam Srikumaran - Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7040, USA
- Publication Details
- Veterinary microbiology, Vol.153(3), pp.332-338
- Academic Unit
- Veterinary Microbiology and Pathology, Department of
- Publisher
- Elsevier B.V
- Identifiers
- 99900547267601842
- Language
- English
- Resource Type
- Journal article