Patterns of Drug Resistance Among Tuberculosis Patients in West and Northwestern Iran

The Epidemiology of first and second-line drug-resistance Mycobacterium tuberculosis complex common species: Evidence from selected TB treatment initiating centers in Ethiopia

Background

Drug-resistance in Mycobacterium tuberculosis complex remains a major health burden in human history and still is a major leading cause of death in developing countries including Ethiopia. Early detection of all forms of drug-resistant Tuberculosis(TB) is a key factor to reduce and contain the spread of these resistant strains.

Methods

A health facility-based cross-sectional study was employed, based on demographic, clinical, and laboratory data collected from 204 patients with bacteriological confirmed TB. Sputum samples were analyzed using conventional TB culture and identification test followed by molecular species identification, and then phenotypic drug susceptibility tests. Data were entered using an excel spreadsheet and exported to SPSS version 20 for analysis. Descriptive analysis; frequencies, and proportions were computed.

Results

Among the 204 sputum samples inoculated in culture media, Mycobacterium species were recovered from 165 specimens, with 160 Mycobacterium tuberculosis complex and five Non- Tuberculosis Mycobacterium(NTM) species. All Mycobacterium tuberculosis complex was found to be M. tuberculosis. Of the five NTM species, 2 M.fortuitum, 2 M.intracellulare, and 1 M.gordonae were identified. Among 160 species of M. tuberculosis isolates, 110(68.8%) were resistant to any of the anti-TB drugs. The resistance pattern was; INH (109, 68.1%), RIF (99, 61.9%), STM (73,45.6%), and EMB (32,20.0%). Mono-resistance was found for INH (7,4.3%) and STM (1,0.6%). Ninety-nine (61.9%) isolates become MDR, while resistance to any of the second-line anti-TB drugs was detected in 9 (5.6%) strains, with 8(5%) Pre-XDR and one (0.6%) XDR cases.

Conclusion

Our findings highlight high frequencies of drug resistance to first and second-line anti-TB drugs.Determining the drug-resistance pattern of MTB is important for programmatic management of drug-resistant TB in Ethiopia. The circulating Pre-XDR and XDR case identified in the current study is alarming to the tuberculosis control program in the country.

Prevalence of tuberculosis, multidrug resistant tuberculosis and associated risk factors among smear negative presumptive pulmonary tuberculosis patients in Addis Ababa, Ethiopia

Background

The diagnoses of active smear negative PTB, remains difficult. As a result, treatment is often carried out empirically relaying on clinical criteria. The distribution and magnitude of smear negative PTB, smear negative MDR-TB and associated factors in the same day diagnosis strategy are not clearly known in the study area. Therefore, this study aimed to determine the prevalence of TB, MDR-TB and associated risk factors among presumptive smear negative pulmonary tuberculosis patients in Addis Ababa, Ethiopia.

Methods

Analytic cross sectional study design was used. A total of 418 smear negative presumptive pulmonary TB patients were enrolled from selected health facilities since August 01, 2017 to January 5, 2018. Sputum samples were examined by Ziehl Neelsen microscopy, Xpert MTB/RIF assay and Culture. Drug susceptibility testing was performed by line probe assay and BACTEC MGIT 960 system. These laboratory tests were performed in Ethiopian Public Health Institute, National TB Reference Laboratory. Data was analyzed by SPSS Ver.20.

Results

From the total of 418 enrolled patients, 27 (6.5%) were Xpert MTB/ RIF and 26 (6.4%) were culture confirmed smear negative PTB patients. The positivity rate among male and female was 10.2 and 3.5% (p = 0.005) respectively. From 26 culture positive isolates 3 (11.54%) were MDR TB; from MDR-TB confirmed isolates 2/23 (8.7%) were among new and 1/3 (33.3%) was among retreatment smear negative presumptive pulmonary TB patients. All Rifampicin resistant smear negative pulmonary TB isolates by Xpert MTB/ RIF assay were found to be MDR TB and 7/26 (26.9%) isolates were INH mono resistant. History of migration found to be a potential factor for developing smear negative pulmonary TB.

Conclusion

In this study a significant proportion of smear negative pulmonary TB was diagnosed. Furthermore, a high smear negative multi drug resistant (MDR) TB and other mono drug resistant TB prevalence was confirmed. Due to the limitations of smear microscopy which is used as a primary diagnostic tool, these TB strains are missed to be diagnosed and transmission continues in the community.

Association between tobacco smoking and drug-resistant tuberculosis

Background

Tobacco smoking is a risk factor for tuberculosis but little is known about the relationship between tobacco smoking and drug-resistant tuberculosis (DR-TB). We undertook a systematic review and meta-analysis to quantitatively assess the association between DR-TB and tobacco smoking.

Methods

We searched for relevant studies in the Ovid MEDLINE, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, WANFANG, and WEIPU data-bases from inception to September 1, 2017. Results were expressed as odds ratios (ORs) with accompanying 95% CIs, and subgroup analyses were performed by study design, smoking type, DR-TB type, and multivariate analysis.

Results

Thirty-three studies related to tobacco smoking and DR-TB were included. We found substantial evidence that tobacco smoking is associated with an increased risk of DR-TB (OR 1.57, 95% CI 1.33–1.86). Associations were also found in subgroup analyses: for multidrug-resistant tuberculosis (OR 1.49, 95% CI 1.19–1.86) and for any DR-TB (OR 1.70, 95% CI 1.3–2.23); the pooled OR was 1.45 (95% CI 1.11–1.90) for current smoking, 2.25 (95% CI 1.46–3.47) for past smoking, and 1.56 (95% CI 1.22–1.98) for smoking history; and similar ORs were also observed in study design and multivariate analysis subgroup analysis.

Conclusion

This study demonstrated that tobacco smoking is an independent risk factor for DR-TB.