School of Veterinary Medicine

Comparative Pathology Lab

Microbiology and Parasitology

A thorough screening of live animal submissions often includes culturing of the nasopharynx, digestive tract or other designated areas for microbiological pathogens and parasites. These cultures are taken during necropsy procedures by our highly trained staff, using sterile techniques and special isolation media.

Other types of microbiology submissions also are generated from the culture of medical implant sites, eye, ear & skin lesions, suspicious sites of irritation or even from urine & fecal samples. Screening for significant bacterial pathogens such as, Corynebacterium, Pasteurella, beta-hemolytic Staphylococcus, Streptococcus, Klebsiella species are performed on submitted samples.

Microbiology Bench

Cultured materials are forwarded to our experienced Microbiology staff for growth and isolation. Using well-established methods, cultures are examined daily for new growth, and unknown colonies are isolated for identification. Strategies for maximizing microorganism isolation have been optimized through our experience in standard veterinary microbiology practice. The Microbiology department at CPL is a comprehensive service, and can rule-out the presence of microorganisms considered to be significant pathogens. All organisms can be identified through the use of sophisticated biochemical media tests. We have access to a continuously updated online database of identification criteria, which allows us to stay current with taxonomic conventions and isolation trends. Based on our findings, we often offer consultation services to managers of lab-animal vivaria.

During necropsy, subjects are microscopically examined for ecto and endoparasites. The most common ecto and endo parasites of rodent colonies are screened through the use of microscopic pelage examinations, direct microscopic examinations, anal tape tests and fecal floatations for ova and parasites. All staff are highly trained to review for these organisms microscopically. Examples of the significant parasites we might encounter in rodents would be:

  • Aspicularis & Syphacia pinworm species
  • Myocoptes & Myobia fur mite species
  • Tritrichomonas, Spironucleus, Chilomastix, Giardia protozoan species

In addition to all these activities, CPL has the capability to monitor the cleanliness and suitability of vivarium environments, importation areas and animal transport vehicles. To wipe cleaned surfaces, we recommend the use of sterile swabs in TSB (tryptic soy broth) media or Letheen broth. Periodically, multiple swabs in TSB tubes, are submitted to cover a large area within a facility. This type of swabbing survey helps to define areas that require close monitoring or extended cleaning routines. It is an essential part of colony management, and often aids in defining husbandry best-practices. Other methods of evaluating cleanliness of equipment and cleaned surfaces, might include the use of RODAC contact media plates, or direct culture of water supply vessels.

Finally, autoclave steam sterilizer and/or vaporized hydrogen peroxide (VHP) system effectiveness are periodically performed through the use of special biological indicator ampules or discs. Please call us if you have questions regarding the use of these types of media.