Frequency of mutations in rpoB and codons 315 and 463 of katG in rifampin- and/or isoniazid-resistant Mycobacterium tuberculosis isolates from northeast Mexico.
A total of 48 isoniazid (INH)- and rifampin (RIF)-resistant Mycobacterium tuberculosis isolates, 19 INH-resistant isolates, and 9 RIF-resistant isolates were randomly selected and tested for detecting mutations at codons 315 and 463 of katG by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), and/or for detecting mutations at a 69-bp region of the rpoB gene by the INNO-LiPA Rif TB assay. Of the 67 INH-resistant isolates tested, 36 (53.7%) showed the mutation at codon 315 of katG; however, none of them showed the mutation at codon 463. The majority of the RIF-resistant samples analyzed (49 of 57, 86.0%) reacted positive with one of the four R-type probes. The R5-pattern (S531L mutation) was the most frequently observed (31 of 57, 54.4%), followed by R4a-pattern (H526Y mutation) 13 isolates (22.8%), R4b-pattern (H526D mutation) 4 isolates (7.0%), and R2-pattern (D516V mutation) 1 isolate (1.8%). Overall, there was agreement between the line probe kit and phenotypic RIF-susceptibility test for 56 (98.2%) of 57 RIF-resistant isolates tested. These results show that the mutation analysis at codon 315 of katG could be used as a screening assay prior to standard susceptibility testing, whereas mutations in the rpoB gene could be used successfully as genetic markers to rapidly detect RIF-resistant M. tuberculosis clinical isolates from northeast Mexico.
Viader-Salvadó
José María
JM
Departamento de Microbiología, Facultad de Medicina, Universidad Autónoma de Nuevo León, Monterrey, Nuevo León, Mexico. jviader@ccr.dsi.uanl.mx
Luna-Aguirre
Claudia Maribel
CM
Reyes-Ruiz
Jorge Mauricio
JM
Valdez-Leal
Ramón
R
del Bosque-Moncayo
Maria de los Angeles
Mde L
Tijerina-Menchaca
Rolando
R
Guerrero-Olazarán
Martha
M
D000995:Antitubercular Agents / Q000494:pharmacology*; D001426:Bacterial Proteins; D003062:Codon; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D007538:Isoniazid / Q000494:pharmacology*; D008800:Mexico; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D010544:Peroxidases / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D012293:Rifampin / Q000494:pharmacology*
D000995:Antitubercular Agents; D001426:Bacterial Proteins; D003062:Codon; D010544:Peroxidases; C076136:catalase HPI; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D007538:Isoniazid; D012293:Rifampin