Activity of Pyrazinamide against <i>Mycobacterium tuberculosis</i> at Neutral pH in PZA-S1 Minimal Medium

• Main Author: Wanliang Shi (Author)
• Format: Book
• Published: MDPI AG, 2021-07-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Susceptibility testing of tuberculosis (TB) drugs on <i>Mycobacterium tuberculosis</i> is essential for the rapid detection of strains resistant to the drugs, providing the patient with effective treatment, and preventing the spread of drug-resistant TB strains. Pyrazinamide (PZA) is one of the first-line agents used for the treatment of TB. However, current phenotypic PZA susceptibility testing is unreliable due to its performance in acidic pH conditions. The aims of this study were to develop minimal media to determine the activity of PZA at a neutral pH at 37 °C to avoid problems caused by an acidic pH, which is currently used in PZA susceptibility tests, and to identify PZA-resistant <i>M. tuberculosis</i> in media with reproducibility and accuracy. Different minimal media were used to determine the activity of PZA using the broth microdilution method with <i>M. tuberculosis</i> H37Ra as the reference strain. The PZA-S1 minimal medium was proposed as the most suitable medium. PZA inhibited the growth of <i>M. tuberculosis</i> in PZA-S1 at a neutral pH of 6.8, which is the optimal pH for <i>M. tuberculosis</i> growth. Moreover, PZA showed activity at a neutral pH on a PZA-S1 agar plate when using the disk diffusion method. PZA-resistant <i>M. tuberculosis</i> could be identified at a neutral pH in PZA-S1 minimal medium. This study establishes valuable information regarding the testing of PZA's susceptibility in relation to <i>M. tuberculosis</i> at a neutral pH of 6.8 with reliability and accuracy in clinical settings.

Item Description

10.3390/antibiotics10080909
2079-6382