Degree Type

Thesis

Date of Award

1-1-2005

Degree Name

Master of Science

Department

Veterinary Microbiology and Preventive Medicine

Major

Veterinary Microbiology

Abstract

The BACTEC MGIT 960 system was evaluated to determine how it compares to the BACTEC 460 radiometric system for recovery of Mycobacterium bovis from tissue samples. Five hundred and six bovine lymph node samples were collected from 21 abattoirs in the United States and three in Mexico between November 2003 and September 2004. Processed samples were inoculated into a MGIT tube, BACTEC 460 vial, Middlebrook 7H10 and Middlebrook 7H11 solid media. The MGIT tubes were inserted into the MGIT 960 instrument for incubation and testing. The BACTEC 460 vials and MGIT tubes were incubated for six weeks (or until positive). Solid media tubes were incubated up to 8 weeks. Ziehl-Neelsen slides were prepared for each type of media to check for contaminants and confirm growth of acid-fast positive rods. Samples containing acid-fast rods were confirmed as members of the M. tuberculosis complex by a nucleic acid assay. Niacin and nitrate biochemical tests were used to distinguish M. bovis from M. tuberculosis isolates. The study shows the MGIT 960 system had a higher recovery rate of M. bovis than the BACTEC 460 and solid media systems. In addition the MGIT 960 system had the lowest mean time to detection. The BACTEC 460 and MGIT 960 systems had similar contamination rates. These results indicate the MGIT 960 system is better than the BACTEC 460 system for recovering M. bovis from tissue samples.

DOI

https://doi.org/10.31274/rtd-180813-8304

Copyright Owner

Nichole Lynn Hines

Language

en

OCLC Number

62354148

File Format

application/pdf

File Size

46 pages

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