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[Selective media for Pasteurella pneumotropica]
K Mikazuki1, K Takahashi, K Nanba
1Aburahi Laboratories, Shionogi and Co., Ltd., Shiga, Japan.
Abstract:
Bacteria from the subcutaneous abscesses which appeared in a laboratory colony of DS mouse since October of 1977 were identified as Pasteurella pneumotropica by various biological examinations. The abscess formation was limited to multiparous female mice over 100 day-age, but virgin females were free from the disease. The MIC of various antibacterial substances showed that potassium tellurite, kanamycin and bacitracin were effective to isolate the organism selectively from various infection sites harboring many other species of bacteria. A novel NKBT medium was prepared by adding these antibacterial substances to the heart infusion agar (HIA) supplemented by 10% Fildes digested blood. A fluid culture medium, TGN broth was prepared for multiplication of the organism by adding 10% Fildes digested blood and potassium tellurite to GN broth. To isolate the organism from the pharyngo-larynx a direct application of mucus wiped off the infection site onto the culture medium was sufficient, but pre-multiplication in the TGN broth was required for isolation of the organism from gut contents before inoculation onto the NKBT medium. The pre-cultivation in the TGN broth vastly improved the recovery of the organism especially from feces. Thereby we could easily detect the latent infection of this bacterium without sacrificing animals.
Insights
Researchers identified Pasteurella pneumotropica in DS mouse abscesses. Novel culture media (NKBT and TGN broth) enable selective isolation and detection of latent infections without animal sacrifice.
Area of Science:
- Microbiology
- Veterinary Pathology
Context:
- Subcutaneous abscesses were observed in a laboratory colony of DS mice.
- Abscesses primarily affected multiparous female mice over 100 days old, while virgin females remained unaffected.
Purpose:
- To identify the causative agent of subcutaneous abscesses in DS mice.
- To develop selective culture media for Pasteurella pneumotropica isolation.
- To establish a method for detecting latent infections without sacrificing animals.
Summary:
- Biological examinations identified Pasteurella pneumotropica as the causative agent.
- Minimum inhibitory concentration (MIC) studies revealed potassium tellurite, kanamycin, and bacitracin as effective selective agents.
- A novel NKBT medium (heart infusion agar with Fildes digested blood and selective agents) and TGN broth were developed.
- Direct swabbing sufficed for pharyngeal isolation, while pre-multiplication in TGN broth significantly improved gut and fecal sample recovery.
Impact:
- The developed culture methods allow for easy detection of latent Pasteurella pneumotropica infections.
- This facilitates non-invasive monitoring of bacterial infections in laboratory mouse colonies.
- Improved diagnostic techniques contribute to better animal health management and research integrity.