1. LABORATORY DIAGNOSIS OF Mycobacterium bovis INFECTION AND STRAIN TYPING OF ISOLATES
Eamon Costello
Central Veterinary Research Laboratory, Backweston, Celbridge, Co. Kildare 1

2. Central Veterinary Research Laboratory Mycobacteriology section
National reference laboratory for tuberculosis in animals
Diagnostics
Histopathology and culture
of tissue samples
Anamnestic antibody ELISA
Research
Tuberculin potency assays

3. Samples submitted for TB Diagnostic tests
Lymph node lesions detected at abattoir post mortem examination of non-reactor cattle: - approx. 5,000 per year
Selected ‘singleton reactor’ cattle: - approx. 600 per year
Reactors from herds where DVO is undertaking epidemiological investigation: - approx. 800 per year

4. Diagnostic methods Macroscopic examination Histopathology Culture
Rapid diagnosis
Good correlation with culture (94%)
85% of lesions diagnosed by histopathology
Culture
Solid media (Stonebrinks + LJ)
Liquid media (MGIT 960)
Blood agar

5. Accuracy of histopathological examination
100
Negative by
Histopathology
(N = 100)
12 (6%)
188 (94%)
Positive by
(N = 200)
Negative by culture
culture

6. MGIT 960 Liquid Culture System
Liquid medium
Growth of mycobacteria leads to depletion of oxygen
Oxygen sensitive fluorescent chemical indicator in the culture tube
System for simultaneous incubation and monitoring of culture tubes

7. Isolate identification procedures Growth characteristics
Growth rate and effect of temperature on growth
Colony colour and morphology
Cording

8. DNA typing methods RFLP analysis Spoligotyping VNTR
2000 isolates typed
Good differentiation of strains
Spoligotyping
PCR based method
50% of isolates SB140
VNTR
Results can be expressed in a
digital format

9. Genetic relationship between strains in different countries Based on spoligotyping
SB120 clonal complex
Continental Europe
Brazil
Cameroon
Chad
SB 140 clonal complex
Ireland
Great Britain
Australia
Canada
Argentina

10. Acknowledgements Kevin Kenny Frances Quigley Don O’Grady Orla Flynn
Tony Gogarty
Gillian Madigan
Jack McGuirk
Joanne McLernon
Damien O’Meara
Jane O’Rourke
Maureen Padden
Elvira Sovsic
Marion Teeling
Dermot Yearsley