TABLE 4.
Mutations at embB 306 and association with the number and combinations of drug resistance in M. tuberculosis isolates
| Number of resistances (type)a | Total no. (%) (n = 175) | No. of isolates (%) in embB 306 group |
Odds ratiob | 95% confidence interval | P value | |
|---|---|---|---|---|---|---|
| Mutant (n = 22) | Wild type (n = 153) | |||||
| Ps | 65 (37) | 1 (4) | 64 (42) | 0.06 | 0.01–0.50 | <0.001c |
| One (EMB, INH, RIF, STR, PZA) | 21 (12) | 0 (0) | 21 (14) | NAd | NA | 0.08c |
| Two (INH+RIF, INH+EMB, INH+STR, EMB+STR, STR+PZA) | 24 (14) | 0 (0) | 24 (15) | NA | NA | 0.04c |
| Three (INH+RIF+EMB, INH+EMB+STR, INH+RIF+STR, INH+STR+PZA) | 17 (10) | 7 (32) | 10 (7) | 6.7 | 2.2–20.1 | <0.001e |
| Four (INH+RIF+EMB+STR, INH+RIF+PZA+STR, INH+RIF+EMB+PZA) | 22 (12) | 7 (32) | 15 (10) | 4.3 | 1.5–12.2 | <0.01e |
| Five (INH+RIF+EMB+PZA+STR) | 26 (15) | 7 (32) | 19 (12) | 3.3 | 1.2–9.1 | <0.01e |
| ≥3 drugs | 65 (37) | 21 (95) | 44 (29) | 52 | 6.8–398.7 | <0.001c |
INHr, isoniazid resistant; RIFr, rifampin resistant; PZAr, pyrazinamide resistant; EMBr, ethambutol resistant; STRr, streptomycin resistant. Drug resistances and combinations in bold were found exclusively in isolates with embB 306 mutations.
The OR was calculated by associating the risk of having a determinate number of resistances with the presence of an embB 306 mutation. The opposite event of each variable was used like a comparison group (none, yes/no; one, yes/no; two, yes/no; three, yes/no; four, yes/no; five, yes/no; ≥3, yes/no).
By Fisher's exact test. P values of <0.05 are significant.
NA, not applicable, as cells with values of 0 do not permit the calculation of OR or confidence interval (CI).
By chi-square test. P values of <0.05 are significant.