Overcoming the Challenges of Pyrazinamide Susceptibility Testing in Clinical Mycobacterium tuberculosis Isolates
| Autor: | E Roycroft, Peter R. Flanagan, Thomas R. Rogers, Lorraine Montgomery, Emanuele Borroni, Simone Mok, MM Fitzgibbon |
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| Rok vydání: | 2021 |
| Předmět: |
0301 basic medicine
Lineage (genetic) Tuberculosis 030106 microbiology Antitubercular Agents Microbial Sensitivity Tests Biology Amidohydrolases Microbiology Mycobacterium tuberculosis 03 medical and health sciences symbols.namesake Drug Resistance Bacterial Genotype medicine Humans Pharmacology (medical) Pharmacology Sanger sequencing Whole genome sequencing Pyrazinamide biology.organism_classification medicine.disease 030104 developmental biology Infectious Diseases Susceptibility Mutation PncA symbols medicine.drug |
| Zdroj: | Antimicrob Agents Chemother |
| ISSN: | 1098-6596 0066-4804 |
| Popis: | Pyrazinamide (PZA) is one of the first-line agents used for the treatment of tuberculosis. However, current phenotypic PZA susceptibility testing in the Bactec MGIT 960 system is unreliable, and false resistance is well documented. Rapid identification of resistance-associated mutations can confirm the phenotypic result. This study aimed to investigate the use of genotypic methods in combination with phenotypic susceptibility testing for confirmation of PZA-resistant Mycobacterium tuberculosis isolates. Sanger sequencing and/or whole-genome sequencing were performed to detect mutations in pncA, rpsA, panD, and clpC1. Isolates were screened for heteroresistance, and PZA susceptibility testing was performed using the Bactec MGIT 960 system using a reduced inoculum to investigate false resistance. Overall, 40 phenotypically PZA-resistant isolates were identified. Of these, PZA resistance was confirmed in 22/40 (55%) isolates by detecting mutations in the pncA, rpsA, and panD genes. Of the 40 isolates, 16 (40%) were found to be susceptible using the reduced inoculum method (i.e., false resistance). No mutations were detected in two PZA-resistant isolates. False resistance was observed in isolates with MICs close to the critical concentration. In particular, East African Indian strains (lineage 1) appeared to have an elevated MIC that is close to the critical concentration. While this study illustrates the complexity and challenges associated with PZA susceptibility testing of M. tuberculosis, we conclude that a combination of genotypic and phenotypic drug susceptibility testing methods is required for accurate detection of PZA resistance. |
| Databáze: | OpenAIRE |
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