Table 2.

Prevalence of each of the possible combinations of resistance phenotypes among 250 clinical MTB isolates

Resistance phenotype	Frequency of recovery
O	0
R	6
E	1
H	26
Z	0
Subtotal	33
OR	0
OE	0
OH	1
OZ	0
RE	1
RH	70
RZ	0
EH	0
EZ	0
HZ	0
Subtotal	72
ORE	0
ORH	9
ORZ	1
OEH	0
OEZ	0
OHZ	0
REH	32
REZ	0
RHZ	14
MHZ	1
Subtotal	57
OREH	13
OREZ	0
OEHZ	0
ORHZ	4
REHZ	28
Subtotal	45
OREHZ	43
Total	250

O, ofloxacin; R, rifampicin; E, ethambutol; H, isoniazid; Z, pyrazinamide.