TABLE 1.
Direct susceptibility testing by MGMT assay and comparison with indirect proportional method in the same clinical specimens
| M. tuberculosis straina | No. of strains with the following test result:b
|
% Agreement | |||
|---|---|---|---|---|---|
| Susceptible by both methods | Resistant by both methods | Sensitive by MG, resistant by LJ | No growth by MG, sensitive by LJ | ||
| Susceptible strains (n = 26) | 21 | 5 | 80 | ||
| MDR strains (resistant to INH and RF) | |||||
| Susceptible to all second-line drugs (n = 3) | 3 | ||||
| Resistant to SM also (n = 1) | 1 | 100 | |||
| Resistant to SM, ETB, and AM also (n = 2) | 2 | ||||
| Resistant to SM and KAN also (n = 1) | 1 | ||||
| Resistant to ETB and PAZ also (n = 1) | 1 | ||||
| XDR strains resistant to INH, RF, CIP, OF, KAN, AM, ETH, and DC (n = 2) | 2 | 100 | |||
| Strains with other resistance patterns | |||||
| Resistant to only ETB (n = 2) | 1 | 1 | 66 | ||
| Resistant to ETB and SM (n = 3) | 2 | 1 | |||
| Resistant to ETB, RF, and AM (n = 1) | 1 | ||||
a
Abbreviations: AM, ampicillin; CIP, ciprofloxacin; DC, doxycycline; ETB, ethambutol; ETH, erythromycin; INH, isonizid; KAN, kanamycin; OF, ofloxacin; PAZ, pyrazinamide; RF, rifampin; SM, streptomycin.
b
MG, malachite green microtube susceptibility assay; LJ, Löwenstein-Jensen culture medium.