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Published on: July 22, 2011
Serotyping of Mannheimia (Pasteurella) haemolytica isolates from the upper Midwest United States
G M Al-Ghamdi1, T R Ames, J C Baker
1Department of Clinical and Population Sciences, University of Minnesota, St. Paul 55108, USA.
Abstract:
Mannheimia (Pasteurella) haemolytica biotype A serotype1 (A1) is the primary bacterial agent responsible for the clinical signs and pathophysiologic events in bovine pneumonic pasteurellosis. The goal of this study was to determine the prevalence of other serotypes of M. haemolytica biotype A organisms obtained from the upper Midwest diagnostic laboratories. A total of 147 M. haemolytica isolates were collected from Minnesota, South Dakota, and Michigan. Isolates were tested against M. haemolytica antisera obtained from the National Animal Disease Center, Ames, Iowa. Results indicated that M. haemolytica serotype 1 represented approximately 60%, serotype 6 represented 26%, and serotype 2 represented 7% of the total examined isolates. In addition, 7% of the isolates were serotype 9, 11, or untypable. This finding suggests that M. haemolytica serotypes other than serotype 1 can be isolated from the lung lesions of diseased cattle and seem to be capable of causing the pathologic changes observed in the lung with pneumonic pasteurellosis.
Insights
Mannheimia haemolytica serotype 1 is a common cause of bovine pneumonic pasteurellosis. However, other serotypes, such as serotype 6 and 2, are also prevalent and can cause lung lesions in cattle.
Area of Science:
- Veterinary Microbiology
- Bovine Respiratory Diseases
Background:
- Mannheimia haemolytica biotype A serotype 1 (A1) is recognized as the primary bacterial pathogen in bovine pneumonic pasteurellosis.
- Understanding the prevalence of other M. haemolytica serotypes is crucial for accurate diagnosis and disease management.
Purpose of the Study:
- To investigate the prevalence of different serotypes of Mannheimia haemolytica biotype A in cattle from the upper Midwest.
- To identify non-serotype 1 M. haemolytica isolates associated with bovine pneumonic pasteurellosis.
Main Methods:
- Collected 147 M. haemolytica isolates from diagnostic laboratories in Minnesota, South Dakota, and Michigan.
- Serotyped isolates using antisera from the National Animal Disease Center.
- Analyzed serotype distribution among the isolates.
Main Results:
- Mannheimia haemolytica serotype 1 accounted for approximately 60% of isolates.
- Serotype 6 represented 26%, and serotype 2 represented 7% of the isolates.
- Serotypes 9, 11, or untypable isolates comprised the remaining 7%.
Conclusions:
- Mannheimia haemolytica serotypes beyond serotype 1 are frequently isolated from diseased cattle lungs.
- These non-serotype 1 serotypes are implicated in causing pathologic changes consistent with pneumonic pasteurellosis.
- The study highlights the importance of considering diverse M. haemolytica serotypes in bovine respiratory disease outbreaks.
