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In vitro characterization of field isolants of Pasteurella multocida from Georgia turkeys
Abstract:
Field isolants of Pasteurella multocida from fowl cholera outbreaks in Georgia turkeys were characterized by three sets of criteria: differential biochemical reactions, in vitro drug sensitivity, and serology. Of the 30 isolants studied, 28 exhibited identical biochemical patterns. These were similar to previously described patterns for turkey isolants of P. multocida. The two exceptions were isolants recovered from the same farm at different times. They differed only in ability to ferment arabinose. The isolants were generally sensitive to broad-spectrum antibiotics in vitro. The majority were also sensitive to the sulfonamides tested. Variation was sufficient, however, to warrant recommending in vitro sensitivity testing as a guide to selection of the proper therapeutic regimen in individual cases. Of the 30 isolants tested, 57% were of Heddleston's serotype 3, 3% were of his type 4, and 40% precipitated with antisera against both types 3 and 4. The large proportion of cross-reactors is unique to Georgia isolants. The biochemical patterns, drug sensitivities, and serological types had no apparent relationship to each other.
Insights
Characterizing Pasteurella multocida from Georgia turkey outbreaks revealed consistent biochemical patterns but varied drug sensitivities and unique serotypes. In vitro sensitivity testing is recommended for effective fowl cholera treatment.
Area of Science:
- Veterinary Microbiology
- Avian Pathology
- Bacterial Pathogenesis
Background:
- Fowl cholera, caused by Pasteurella multocida, is a significant disease in turkeys.
- Understanding field isolates' characteristics is crucial for disease management and treatment strategies.
Purpose of the Study:
- To characterize Pasteurella multocida isolates from Georgia turkey outbreaks.
- To evaluate biochemical profiles, in vitro antibiotic sensitivity, and serological types of these isolates.
Main Methods:
- Isolates were analyzed using differential biochemical reactions.
- In vitro drug sensitivity testing was performed against various antibiotics and sulfonamides.
- Serological typing was conducted using Heddleston's antisera (types 3 and 4).
Main Results:
- Twenty-eight of thirty isolates showed identical biochemical patterns, consistent with previous turkey isolates.
- Most isolates were sensitive to broad-spectrum antibiotics and tested sulfonamides in vitro.
- A significant proportion (40%) of isolates cross-reacted with antisera for serotypes 3 and 4, a unique finding for Georgia isolates.
Conclusions:
- Biochemical profiles, drug sensitivities, and serotypes of P. multocida isolates from Georgia turkey farms showed limited correlation.
- In vitro antibiotic sensitivity testing is recommended to guide therapeutic regimens for fowl cholera in turkeys.
- The high prevalence of cross-reacting serotypes in Georgia warrants further investigation.