Potential for erroneous results indicating resistance when using the Bactec MGIT 960 system for testing
Pamela Chedore1, Lina Bertucci, Joyce Wolfe
1Public Health Laboratory-Toronto, Ontario Agency for Health Protection and Promotion, 81 Resources Road, Toronto, Ontario M9P 3T1, Canada. Pam.Chedore@oahpp.ca
Abstract:
During susceptibility testing of 743 isolates of Mycobacterium tuberculosis to pyrazinamide (PZA) using the Bactec 960 system, 57 (7.7%) isolates showed PZA resistance. Repeat testing of resistant isolates with the Bactec 460 reference method confirmed 33 (4.4%) of these isolates as resistant, and 24 (3.2%) were susceptible. Erroneous results for resistance with the Bactec 960 were confirmed by testing the 24 discordant isolates for pyrazinamidase and mutations in the pncA gene.
Related Concept Videos
Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
Automated Microbial Diagnostics
Pulmonary Tuberculosis V
Latent tuberculosis infection occurs when TB bacteria are present in a person's body, but are not causing illness or symptoms. It is not contagious, and preventive treatment is crucial to avoid the progression...

