Primary Drug Resistance Patterns of Mycobacterium Tuberculosis Isolates Among New Pulmonary Tuberculosis Patients in Bahir Dar, Ethiopia
No Thumbnail Available
Date
2003-04
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
The increase in drug resistant tuberculosis, and particularly multi-drug resistant tuberculosis
(MDR-TB) as well as the neglect of discovery and development of new anti-TB drugs that are
active against TB/ MDR-TB at present, increased the need for knowledge of the prevalence
and patterns of primary resistance among Mycobacterium tuberculosis isolates in the
community. A total of 76 M. tuberculosis isolates were recovered from sputa specimens of
newly diagnosed pulmonary tuberculosis (PTB) patients in Bahir Dar, Ethiopia and confirmed
by culture and standard biochemical tests on L-J media. The specimens were collected
between February and April 2001. Drug susceptibility testing was performed according to the
indirect proportion method. The prevalence and patterns of primary resistance were
determined and any association between patients' characteristics (sex and age) and primary
resistance were analyzed using chi-square test. The results of the present study showed that
primary mono-resistance was highest to streptomycin (14.5 %) followed by isoniazid (2.6 %).
All isolates were susceptible to rifampicin and ethambutol. Primary resistance to any drug
was found in 14 of new PTB patients (18.4 %); and any primary resistance to streptomycin
was 15.8 %; any isoniazid resistance was 3.9 %; any rifampicin resistance was 1.3 %, and it
was nil to ethambutol. The rate of Primary MDR-TB was 1.3 %. Single drug resistance was
higher in males (n=8, 61.5 % of mono-resistant cases) than in females (n=5, 38.5 %). Primary
resistance to a single drug was found in 4 patients in the age group 15-24 (30.8 %), 4 in the
group 25-34 (30.8 %) and 5 in the group 35-44 (38.5 %). Thus, the proportion of patients that
had primary mono-resistance was similar in all age groups and the age groups between 15-44
were totally affected by primary drug resistant strains. Primary MDR-TB (with HRS pattern)
occurred in one patient (1.3 %) belonged to the age group 25-34. Single drug resistance to
streptomycin was found in 8 males (73 %) and in 3 female patients (27 %). Isoniazid monoresistance
was found only in female patients (n = 2, 100 %). The age range of TB patients
that had primary resistant isolates of M. tuberculosis were between 15-44 years, with mean
age of 27.4 years. However, primary resistance was not associated with age and gender
(P>0.05). The drugs isoniazid, ethambutol and rifampicin remain drugs of choice to treat the
majority of drug susceptible TB cases in Bahir Dar. The results of this study underscore the
need for periodic monitoring of drug resistance and improving in TB control performance
both at local and country level.
Description
Keywords
Biology