system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, OBJECTIVE, METHODS, RESULTS. Meshes: Amidohydrolases, Antitubercular Agents, China, DNA Mutational Analysis, DNA, Bacterial, Drug Resistance, Multiple, Bacterial, Extensively Drug-Resistant Tuberculosis, Fluoroquinolones, Gene Frequency, Genotype, Humans, Microbial Sensitivity Tests, Mutation, Mycobacterium tuberculosis, Paris, Phenotype, Pyrazinamide, Rifampin, Tuberculosis, Multidrug-Resistant.
user
Does pyrazinamide resistance in Mycobacterium tuberculosis arise after rifampicin and fluoroquinolone resistance? Context: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (TB) constitute a major public health concern. To determine the timing of pncA mutations that confer pyrazinamide (PZA) resistance in relation to mutations conferring resistance to isoniazid (INH) and rifampicin (RMP). Isolates from two major urban centres--Paris (101 strains) and Shanghai (171 strains)--were investigated for the association of pncA mutations with resistance to drugs other than PZA. The proportion of pncA mutations found in INH-monoresistant strains was not increased.
assistant
pncA mutations associated with PZA resistance were found almost exclusively in MDR-TB strains, underlining the importance of determining PZA resistance when treating MDR- or XDR-TB. Final Decision: yes