Rapid identification of tissue micro-organisms in skin biopsy specimens from domestic animals using polyclonal BCG antibody.

This research evaluates the use of polyclonal anti-Mycobacterium bovis (BCG) for the quick identification of micro-organisms in animal skin biopsy specimens, finding it to be a suitable screening technique for most common bacterial and fungal organisms.

Research Context

• The study explores the use of a specific immunostain for identifying bacterial and fungal micro-organisms rapidly in skin biopsy specimens derived from domestic animals, specifically the dog, cat, horse, ox, and llama.
• The immunostain in focus is known as polyclonal anti-Mycobacterium bovis (BCG).
• This immunostain was evaluated against confirmed archival cases infected with an extensive range of micro-organisms, including Mycobacteria, Nocardia, Actinobacillus, Actinomyces, Streptococcus/Staphylococcus, Dermatophilus, spirochetes, Blastomyces, Coccidioides, Cryptococcus, Histoplasma, dermatophytes, Malassezia, Sporothrix, Leishmania, Pythium, phaeohyphomycetes and Prototheca.

Research Findings

• The study found that the anti-BCG immunostain efficiently labelled bacteria and fungi in the specimen, with high sensitivity and minimal background staining.
• However, the anti-BCG immunostain did not show any reaction with spirochetes and protozoa, specifically Leishmania.
• No difference in immunostain reactions was noted across the different species of animals used in the study.

Research Implications

• The findings suggest that the polyclonal anti-BCG immunostain could serve as a suitable screening tool for the rapid identification of the most common bacterial and fungal organisms present in paraffin-embedded specimens used for biopsy.
• The study also found that mycobacterial and nocardial organisms, in particular, were identified more readily with the anti-BCG immunostain as opposed to histochemical stains, indicating that the anti-BCG immunostain could be more useful in detecting these specific organisms.
• Despite its utility for most organisms, the anti-BCG immunostain may not be suitable for the identification of spirochetes and protozoan organisms, which would require a different identification method considering it didn’t solicit a reaction in this research.

Conclusions

• The study reaffirms the efficacy of using polyclonal anti-BCG as an efficient immunostain for rapid detection of bacteria and fungi in skin biopsy specimens from various veterinary species.
• Further studies may be needed to develop suitable screening tools for organisms such as spirochetes and protozoa that were not detectable with this immunostain.