Mutant prevention concentration of isoniazid, rifampicin and rifabutin against Mycobacterium tuberculosis.
BACKGROUND
Mutant prevention concentration (MPC) is a new parameter that may be of aid in determining the risk of resistant mutants being selected.


METHODS
The MPCs of 224 Mycobacterium tuberculosis clinical isolates were estimated by plating more than 10(10) cells on drug-containing agar and determining the concentration that allowed no colony growth. Antibiotics used were isoniazid, rifampicin and rifabutin.


RESULTS
The MPC90 of clinical isolates in our setting is 2.4, 2.2 and 0.4 mg/l for isoniazid, rifampicin and rifabutin, respectively.


CONCLUSIONS
Isoniazid and rifampicin are two drugs that present a low risk of selection of resistant mutants when used in monotherapy. However, determination of the MPC of each strain can provide data to minimize this risk and thus enable treatment to be optimized.
Rodríguez
J C
JC
Sección Microbiología, Hospital General Universitario de Elche, Universidad Miguel Hernández, Elche, Spain. micro_elx@gva.es
Cebrián
L
L
Ruiz
M
M
López
M
M
Royo
G
G
D000995:Antitubercular Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D024881:Drug Resistance, Bacterial / Q000235:genetics; D007538:Isoniazid / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D017828:Rifabutin / Q000494:pharmacology*; D012293:Rifampin / Q000494:pharmacology*
D000995:Antitubercular Agents; D017828:Rifabutin; D007538:Isoniazid; D012293:Rifampin