Factors associated with tuberculosis treatment initiation among bacteriologically negative individuals evaluated for tuberculosis: an individual patient data meta-analysis

Background

Globally, over one-third of pulmonary tuberculosis (TB) disease diagnoses are made based on clinical criteria after a negative diagnostic test result. Understanding factors associated with clinicians' decisions to initiate treatment for individuals with negative test results is critical for predicting the potential impact of new diagnostics.

Methods

We performed a systematic review and individual patient data meta-analysis using studies conducted between January/2010 and December/2022 (PROSPERO: CRD42022287613). We included trials or cohort studies that enrolled individuals evaluated for TB in routine settings. In these studies participants were evaluated based on clinical examination and routinely-used diagnostics, and were followed for ≥1 week after the initial test result. We used hierarchical Bayesian logistic regression to identify factors associated with treatment initiation following a negative result on an initial bacteriological test (e.g., sputum smear microscopy, Xpert MTB/RIF).

Findings

Multiple factors were positively associated with treatment initiation: male sex [adjusted Odds Ratio (aOR) 1.61 (1.31-1.95)], history of prior TB [aOR 1.36 (1.06-1.73)], reported cough [aOR 4.62 (3.42-6.27)], reported night sweats [aOR 1.50 (1.21-1.90)], and having HIV infection but not on ART [aOR 1.68 (1.23-2.32)]. Treatment initiation was substantially less likely for individuals testing negative with Xpert [aOR 0.77 (0.62-0.96)] compared to smear microscopy and declined in more recent years.

Interpretation

Multiple factors influenced decisions to initiate TB treatment despite negative test results. Clinicians were substantially less likely to treat in the absence of a positive test result when using more sensitive, PCR-based diagnostics.

Funding

National Institutes of Health.

Research in context

Evidence before this study: In countries with a high burden of tuberculosis, over one-third of notified cases for pulmonary TB are diagnosed based on clinical criteria, without bacteriological confirmation of disease ('clinical diagnosis'). For these individuals with negative bacteriological test results, there is limited evidence on the factors associated with higher or lower rates of clinical diagnosis. In the context of individual clinical trials, some analyses have reported lower rates of treatment initiation for individuals testing negative on new cartridge-based PCR tests (e.g., Xpert MTB-RIF), as compared to individuals testing negative in sputum smear microscopy.Added value of this study: This study conducted a systematic review of studies that collected data on patient characteristics and treatment initiation decisions for individuals receiving a negative bacteriological test result as part of initial evaluation for TB. Patient-level data from 13 countries across 12 studies (n=15121) were analyzed in an individual patient data meta-analysis, to describe factors associated with clinicians' decisions to treat for TB disease. We identified significant associations between multiple clinical factors and the probability that a patient would be initiated on TB treatment, including sex, history of prior TB, reported symptoms (cough and night sweats), and HIV status. Controlling for other factors, patients testing negative on PCR-based diagnostics (e.g., Xpert MTB/RIF) were less likely to be initiated on treatment than those testing negative with smear microscopy.Implications of all the available evidence: Rates of clinical diagnosis for TB differ systematically as a function of multiple clinical factors and are lower for patients who test negative with new PCR-based diagnostics compared to earlier smear-based methods. This evidence can be used to refine diagnostic algorithms and better understand the implications of introducing new diagnostic tests for TB.

Bacterial pathogens in Xpert MTB/RIF Ultra-negative sputum samples of patients with presumptive tuberculosis in a high TB burden setting: a 16S rRNA analysis

In patients with presumptive tuberculosis (TB) in whom the diagnosis of TB was excluded, understanding the bacterial etiology of lower respiratory tract infections (LRTIs) is important for optimal patient management. A secondary analysis was performed on a cohort of 250 hospitalized patients with symptoms of TB. Bacterial DNA was extracted from sputum samples for Illumina 16S rRNA sequencing to identify bacterial species based on amplicon sequence variant level. The bacterial pathogen most likely to be responsible for the patients' LRTI could only be identified in a minority (6.0%, 13/215) of cases based on 16S rRNA amplicon sequencing: Mycoplasma pneumoniae (n = 7), Bordetella pertussis (n = 2), Acinetobacter baumanii (n = 2), and Pseudomonas aeruginosa (n = 2). Other putative pathogens were present in similar proportions of Xpert Ultra-positive and Xpert Ultra-negative sputum samples. The presence of Streptococcus (pseudo)pneumoniae appeared to increase the odds of radiological abnormalities (aOR 2.5, 95% CI 1.12-6.16) and the presence of S. (pseudo)pneumoniae (aOR 5.31, 95% CI 1.29-26.6) and Moraxella catarrhalis/nonliquefaciens (aOR 12.1, 95% CI 2.67-72.8) increased the odds of 6-month mortality, suggesting that these pathogens might have clinical relevance. M. pneumoniae, B. pertussis, and A. baumanii appeared to be the possible causes of TB-like symptoms. S. (pseudo)pneumoniae and M. catarrhalis/nonliquefaciens also appeared of clinical relevance based on 16S rRNA amplicon sequencing. Further research using tools with higher discriminatory power than 16S rRNA sequencing is required to develop optimal diagnostic and treatment strategies for this population.IMPORTANCEThe objective of this study was to identify possible bacterial lower respiratory tract infection (LRTI) pathogens in hospitalized patients who were initially suspected to have TB but later tested negative using the Xpert Ultra test. Although 16S rRNA was able to identify some less common or difficult-to-culture pathogens such as Mycoplasma pneumoniae and Bordetella pertussis, one of the main findings of the study is that, in contrast to what we had hypothesized, 16S rRNA is not a method that can be used to assist in the management of patients with presumptive TB having a negative Xpert Ultra test. Even though this could be considered a negative finding, we believe it is an important finding to report as it highlights the need for further research using different approaches.

Discordance between genotypic and phenotypic methods for the detection of rifampicin and isoniazid resistant Mycobacterium tuberculosis and the correlation with patient treatment outcomes

Background

Accurate drug susceptibility testing (DST) of Mycobacterium tuberculosis (MTB) is essential for proper patient management. We investigated discordance between genotypic (Xpert MTB/RIF and MTBDRplus) and phenotypic (MGIT 960) methods for the detection of rifampicin (RIF) and isoniazid (INH) resistant MTB and its correlation with patient treatment outcomes in Jimma, Southwest Oromia, Ethiopia.

Methods

A retrospective study was conducted on 57 stored MTB isolates with known Xpert RIF resistance status (45 RIF resistant and 12 RIF susceptible) at Jimma University Mycobacteriology Research Center from November 2, 2021, to December 28, 2022. We did MTBDRplus and phenotypic DST (using the Mycobacterial Growth Indicator Tube (MGIT) system). The Xpert and MTBDRplus results were compared using phenotypic DST as a reference standard method. The treatment outcome was determined as per national guideline. The discordance between the genotypic and phenotypic DST was calculated using GraphPad software.

Results

Among the 57 MTB isolates, six (10.5 %) had discordant results between the two DST methods. Xpert yielded five discordant results for RIF when compared with phenotypic DST (kappa coefficient (κ) = 0.76, 95 % confidence interval 0.56-0.96). The MTBDRplus compared with phenotypic DST gave three discordant results for RIF (κ = 0.86, 95 % confidence interval 0.71-1.00) and three for INH (κ = 0.86, 95 % confidence interval 0.70-1.00). Compared with Xpert, MTBDRplus yielded lower discordance with phenotypic DST for RIF. Out of six patients with discordant results, three had unfavorable outcomes while the other three were cured. Of the three patients with unfavorable outcomes, only one patient has received an inappropriate treatment regimen. There was no correlation between unfavorable outcomes and incorrect treatment regimens due to discordant results (Χ2 = 0.404; P = 0.525).

Conclusions

Discordance between genotypic and phenotypic DST for RIF or INH occurred in 10.5 % of isolates. Only one patient with discordant results has received an inappropriate treatment regimen, resulting in an unfavorable outcome. The impact of parallel use of rapid molecular assay with phenotypic DST on patient treatment outcomes requires further study.

Resistance to pyrazinamide in Mycobacterium tuberculosis complex isolates from previously treated tuberculosis cases in Southwestern Oromia, Ethiopia

Objective

Pyrazinamide (PZA) susceptibility testing is important to develop evidence-based algorithms for case management. We aimed to assess the prevalence of PZA-resistance and its impact on treatment outcomes in previously treated tuberculosis (TB) cases in southwestern Oromia, Ethiopia.

Methods

A Phenotypic Drug Susceptibility Testing (DST) of PZA with BACTEC MGIT 960 was conducted at the Mycobacteriology Research Center of Jimma University (MRC-JU) from June to November 2021 on sixty-six Mycobacterium tuberculosis complex (MTBC) isolates from previously treated TB cases. SPSS software package version 21 was used. The differences in the proportion of PZA resistance between the groups were compared using the chi squared test. Logistic regression was used to identify the association between PZA resistance and treatment outcomes.

Results

Among 66 MTBC isolates (49 rifampicin-resistant and 17 rifampicin-sensitive) included in this study, 31.8 % were resistant to PZA. The proportion of PZA resistance was almost three times higher in previously treated TB cases with rifampicin resistance than in rifampicin-sensitive patients (38.8 % vs. 11.8 %, p = 0.039). An unfavorable treatment outcome was documented for 23 % (15/65) of the participants. Patients with PZA resistance were almost four times more likely to have an unfavorable treatment outcome than patients with PZA sensitive (aOR 4.2, 95 % CI: 1.13-15.3).

Conclusions

The prevalence of PZA resistance was high compared to the pooled PZA resistance estimated worldwide. The majority of TB cases with PZA resistance had an unfavorable treatment outcome. PZA susceptibility testing should be included in the multidrug-resistant TB diagnostic algorithm to improve management of these patients.

Combination of Xpert® MTB/RIF and DetermineTM TB-LAM Ag improves the diagnosis of extrapulmonary tuberculosis at Jimma University Medical Center, Oromia, Ethiopia

BACKGROUND

Ethiopia is one of the high burden countries for extrapulmonary tuberculosis (EPTB); however, the prompt diagnosis of EPTB remains challenging. This study is aimed to evaluate the diagnostic performance of Xpert MTB/RIF and DetermineTM TB-LAM Ag (TB-LAM) for the prompt diagnosis of EPTB in Ethiopia.

METHODS

A total of 147 presumptive EPTB patients, including 23 HIV- positive participants were enrolled. Extra-pulmonary samples were collected from all presumptive EPTB cases and tested for Mycobacterium tuberculosis complex (MTBC) using fluorescent microscopy, Xpert MTB/RIF, and culture. Additionally, urine samples were also collected from 126 participants and were tested by DetermineTM TB-LAM Ag (Alere Inc, Waltham, USA). The Sensitivity and specificity of Xpert and TB- LAM tests were calculated by comparing with a composite reference standard (CRS), which comprises smear microscopy, culture and response to empirical anti-TB treatment.

RESULTS

Of 147 patients, 23 (15.6%) were confirmed EPTB cases (culture-positive), 14 (9.5%) were probable EPTB (clinically, radiologically or cytologically positive and received anti-TB treatment with good response), and 110 (74.8%) were classified as "non- TB" cases. Compared to the composite reference standard (CRS), the overall sensitivity and specificity of Xpert MTB/RIF were 43.2% and 100%, respectively with the highest sensitivity for Lymph node aspirate (85.7%) and lower sensitivity for pleural fluid (14.3%) and 100% specificity for all specimen types. The sensitivity and specificity of TB-LAM were 33.3% and 94.4% respectively with the highest sensitivity for HIV co-infected participants (83.3%). The sensitivity of the combination of Xpert MTB/RIF and TB-LAM tests regardless of HIV status was 61.1% whereas the sensitivity was improved to 83.3% for HIV-positive cases.

CONCLUSION

TB-LAM alone has low sensitivity for EPTB diagnosis; however, the combination of TB-LAM and Xpert MTB/RIF improves the diagnosis of EPTB particularly for countries with high EPTB and HIV cases.

Immunogenicity and Efficacy Evaluation of Vero Cell-Adapted Infectious Bursal Disease Virus LC-75 Vaccine Strain

Introduction

Infectious bursal disease virus (IBDV) is an avian viral pathogen that causes infectious bursal disease (IBD) of chickens. The disease has been endemic in Ethiopia since 2002, and vaccination has been practiced as the major means of disease prevention and control. An IBD vaccine is produced in Ethiopia using primary chicken embryo fibroblast (CEF) cell, which is time-consuming, laborious, and uneconomical. The present study was carried out to develop cell-based IBDV LC-75 vaccine using Vero cells and to evaluate the safety, immunogenicity and protection level.

Methods

Identity of the vaccine seed was confirmed with gene-specific primers using reverse transcription polymerase chain reaction (RT-PCR). Confluent monolayer of Vero cells was infected with vaccine virus and serial passage continued till passage 10. A characteristic virus-induced cytopathic effect (CPE) was observed starting from passage 2 on the third day post-infection. The infectious titer of adapted virus showed a linear increment along the passage level. The virus-induced specific antibody was determined using indirect ELISA after vaccination of chicks through ocular route.

Results

The antibody titer measured from Vero cells vaccinated chicks revealed similar level with the currently available CEF cell-based vaccine, hence no significant difference. Chicks vaccinated with Vero cell adapted virus showed complete protection against very virulent IBDV, while unvaccinated group had 60% morbidity and 25% mortality.

Conclusion

It is concluded that the IBDV vaccine strain well adapted on Vero cells and found to be immunogenic induces antibody development and successfully protects chicks against challenge with the circulating field IBDV isolate. Hence, it is recommended to produce IBD vaccine using Vero cell culture at the industrial scale to conquer the limitations caused by using CEF cells and thus to vaccinate chicks population to protect against the circulating IBDV infection.

Assessment of Ethical Compliance of Handling and Usage of the Human Body in Anatomical Facilities of Ethiopian Medical Schools

Background

Human anatomy has historically been a cornerstone in medical education and is special in that it uses human remains kept in various anatomical facilities like a morgue, gross anatomy laboratory, or museums for instruction and research. While serving knowledge advancement facilitating clinical practice and research, human cadaver handling, and usage at all levels, such as cadaver sourcing, transportation, storage, preservation, dissection, and final disposal deserves in return the utmost respect. In Ethiopia, even though there is not enough information on when, where, and by whom the first cadaver dissection was conducted, dissection is being conducted in many of its medical schools. Despite ethical necessity surrounding human body usage in every anatomical setting, there is still ethical and legal uncertainty due to several challenging barriers which is severe in developing nations including Ethiopia. The aim of this study is, therefore, to assess ethical practices of handling and usage of the human body to promote, in the near future, formulation and implementation of acceptable, respectful, and ethical guidelines for the anatomy dissection laboratories and related settings in Ethiopia.

Methods

A multicentered cross-sectional study was used at selected anatomy facilities of eight Ethiopian medical schools. The collected data through structured questionnaires and checklists were cleaned, preset and entered in to SPSS version 20 for analysis. Internal consistency and reliability were measured by using Cronbach’s alpha.

Results

The study result showed vivid human body ethical breaches that ranged from lack of power by anatomy unit to oversee the process during sourcing, transportation, embalming, caring, and dissection of cadavers in the anatomy laboratories to student’s mistreatment of cadavers.

Conclusion

In addition to lack of compliance due to lack of standard ethical guidelines or policies regarding human body usage, the compliance-based professional development is also nonexistent. The ethical way of body sourcing is through body donation; however, in Ethiopia, anatomy teaching exclusively depends on unclaimed bodies. Using a body for dissection that is solely sourced unethically may generate a negative emotional sense of life for anatomy instructors, technical assistants, morticians, and medical students. We inspire better provision of moral and ethical exercise with the good practice concerning the human body through recognizing the humanity and uniqueness of the deceased person. The results of this study serve as a serious condemnation of practices in Ethiopian anatomy facilities and we urge the Anatomical Society of Ethiopia to play its part in changing the present practices related to ethical and legal uncertainty of the human body usage.

Diagnostic implications and inpatient mortality related to tuberculosis at Jimma Medical Center, southwest Ethiopia

BACKGROUND

Tuberculosis (TB) is one of the major public health problems in Ethiopia. Determining discharge outcome of TB cases helps to understand the effectiveness of TB diagnosis effort to improve case management. The objective of this study was to assess discharge outcomes and factors associated with death among patients on TB treatment admitted in a referral hospital in southwest Ethiopia.

METHODS

A retrospective study was conducted in Jimma Medical Center by reviewing medical records of TB patients (age ≥15 years) admitted to medical wards from January 2015 to December 2017. Demographic and related data was collected using data collection format. The clinical evaluation outcome of an individual patient at discharge was recorded. Descriptive statistics were used to summarize participant characteristics. Multivariate logistic regression analyses were used to evaluate the risk factors for TB mortality.

RESULTS

Among 465 patients included in the review, 225 (48.4%) were pulmonary (PTB) and 240 (51.6%) extra-pulmonary TB (EPTB) cases. Overall, 190 (40.9%) had bacteriologically confirmed for TB. HIV status was documented for 340 (73.1%) of them; 93 (27.4%) were found to be positive. The prevalence of HIV infection among EPTB and PTB cases was 50/275 (18.2%) and 43/190 (22.8%), respectively. A quarter of the patient, 114 (24.5%), died in the hospital while the rest were discharged with clinical improvement. Compared to smear positive PTB, the risk of death was two times higher in patients with smear negative PTB cases (aOR 2.3, 95% CI: 1.3-4.2). TB patients with coronary obstructive pulmonary disease (COPD) (aOR 4.6, 95% CI: 1.3-16.7), diabetes mellitus (aOR 5.7, 95% CI: 1.5-23.7), heart disease (aOR 3.8, 95% CI: 1.4-10.4) had about four-fold increased risk of death. HIV-positive patients had a higher risk of mortality (aOR 2.9, 95% CI: 1.7-5.0) than HIV-negative patients. The risk of death was not affected by the type of TB diagnosed, as 27.6% of EPTB and 31.9% PTB were died (p = 0.457).

CONCLUSION

TB was associated with high inpatient mortality at Jimma Medical Center. Mortality was found to be higher among unconfirmed cases, those with COPD, diabetes mellitus, heart disease and HIV infection. Thus, any effort to curtail mortality in such high TB burden setting should focus on improving TB diagnosis and addressing major comorbid medical conditions.

The role of chest radiography in the diagnosis of bacteriologically confirmed pulmonary tuberculosis in hospitalised Xpert MTB/RIF-negative patients

The role of chest radiography to diagnose active tuberculosis in symptomatic patients who have a negative Xpert MTB/RIF (Xpert) test result is unclear. This study aimed to assess the performance of chest radiography and the value of chest radiography findings for a prediction tool to identify cases of active pulmonary tuberculosis among symptomatic, Xpert-negative hospitalised patients.

Xpert-negative patients hospitalised between January and July 2019 at Jimma University Medical Center in Ethiopia were assessed by mycobacterial culture and chest radiography. Chest radiography was interpreted by a clinician for clinical decision making and by a radiologist for research purposes. Using bacteriological confirmation as the reference standard, the performance of chest radiography to diagnose active tuberculosis was assessed by the area under the receiver operating characteristic curve (AUC); predictors of active tuberculosis were identified using bivariate and multivariate logistic regression analyses.

Of 247 Xpert-negative patients, 38% and 40% were classified as suggestive of tuberculosis by clinician and radiologist, respectively. Of the 39 (15.8%) bacteriologically confirmed cases, 69% and 79% were classified as having chest radiography findings suggestive of tuberculosis by clinician or radiologist, respectively. While there was a strong association between bacteriologically confirmed tuberculosis and chest radiography classified by clinician as suggestive of tuberculosis (adjusted OR 2.7, 95% CI 1.2–6.6), chest radiography with signs typical of tuberculosis (adjusted OR 5.3, 95% CI 2.1–14.4) or compatible with tuberculosis (adjusted OR 5.1, 95% CI 1.3–20.0), the positive predictive value of the chest radiography was low (27% and 34% for classification by clinician and radiologist, respectively). The addition of chest radiography findings by clinician or radiologist to clinical characteristics did not improve the performance of the prediction tool, with similar risk classification distribution, AUCs and negative and positive prediction values.

Despite the strong association between chest radiography findings and active tuberculosis among hospitalised Xpert negative individuals, chest radiography findings did not improve the performance of a risk prediction tool based solely on clinical symptoms. Countries with a high tuberculosis/HIV burden should urgently replace Xpert by the more sensitive Xpert Ultra assay to improve the diagnosis of active tuberculosis.

In hospitalised people with symptoms of TB and a negative Xpert assay, knowledge of chest radiography findings does not improve the ability of clinicians to predict the presence of active TB beyond what is possible based solely on clinical characteristicshttps://bit.ly/30s72mX

Role of empiric treatment in hospitalized patients with Xpert MTB/RIF-negative presumptive pulmonary tuberculosis: A prospective cohort study

OBJECTIVES

The ability of clinical algorithms to identify tuberculosis disease and the impact of empiric treatment on survival in people with a negative Xpert MTB/RIF (Xpert) result remains poorly documented.

METHODS

Hospitalized Xpert-negative patients (125 initiated on empiric tuberculosis treatment based on a clinical algorithm and 125 in whom tuberculosis treatment was not started) were enrolled. Sputum samples were evaluated for Mycobacterium tuberculosis by culture. All study participants were followed up for 6 months.

RESULTS

Xpert-negative inpatients in whom empiric tuberculosis treatment was initiated were more likely to have microbiological confirmed tuberculosis compared to those in whom empiric tuberculosis treatment was not started (24.8% vs 6.4%, p=0.0001). Six-month risk of death was 5.2%, but the risk was twice as high in people with bacteriological confirmation of TB (10.3% vs 4.3%, p=0.12). Cardinal symptoms of TB were associated with bacteriological confirmation and a decision to start empiric treatment. The positive predictive value of the clinical algorithm was 24.8% and empiric treatment did not affect 6-month risk of death (5.6% vs 4.8%, p=0.78).

CONCLUSIONS

Clinical algorithm identifies the majority of confirmed tuberculosis cases among Xpert-negative inpatients. Empiric treatment did not impact survival and resulted in substantial overtreatment. The more sensitive Xpert Ultra assay should be used to eliminate the need for empiric tuberculosis treatment.

Treatment outcomes and associated factors in tuberculosis patients at Jimma University Medical Center: A 5-year retrospective study

Background

Monitoring the outcome of tuberculosis (TB) treatment and investigating factors associated with unsuccessful outcome are essential, as unsuccessful treatment fuels resistance to antibiotics. This study aimed to investigate the treatment outcome and associated factors with an unsuccessful outcome at Jimma University Medical Center (JUMC), Southwest Ethiopia.

Methods

A 5-year retrospective analytical study, including all types of TB cases who sought care at JUMC between September 1, 2012, and August 31, 2017, was conducted. Treatment outcomes and TB types were categorized according to the National TB Control guideline. Bivariate analysis was used to analyze the association between treatment outcome and potential variables.

Results

Overall data from 1249 patients' records were included in the study. The proportion of male patients was higher (815, 65.3%) than that of females. The mean age (± standard deviation, range) of the cases was 26 (±11. 6, 1-71) years. Of the total, 292 (23.3%) were smear-positive pulmonary TB (PTB), 489 (39.2%) smear-negative PTB, and 468 (37.5%) extra-PTB (EPTB) cases. Available treatment outcomes indicate that 253 (20.2%) were cured, 850 (68.0%) completed therapy, 58 (4.8%) died, 83 (6.6%) defaulted, and 5 (0.4%) failed the therapy. About 76 (5.6%) cases were transferred out and 44 (3.2%) cases were lost to follow-up. In total, 146 (11.7%) patients had an unsuccessful outcome. Unsuccessful treatment outcome was associated with smear-negative PTB (odds ratio [OR] =2.0, 95% confidence intervals [CI] =1.1, 3.7), EPTB (OR = 2.1, 95% CI = 1.2, 3.4), and unknown human immunodeficiency virus (HIV) status (OR = 7.9, 95% CI = 2.5, 25.0).

Conclusion

The treatment success rate of overall TB patients is lower than end TB Strategy target of ≥90% success rate. Smear-negative PTB, EPTB cases, and those with unknown HIV status tend to have unsuccessful outcome.

Drug resistance-conferring mutations in Mycobacterium tuberculosis from pulmonary tuberculosis patients in Southwest Ethiopia

OBJECTIVE/BACKGROUND

The nature and frequency of mutations in rifampicin (RIF) and isoniazid (INH) resistant Mycobacterium tuberculosis isolates vary considerably according to geographic locations. However, information regarding specific mutational patterns in Ethiopia remains limited.

METHODS

A cross-sectional prospective study was carried out among confirmed pulmonary tuberculosis cases in Southwest Ethiopia. Mutations associated with RIF and INH resistances were studied using GenoType MTBDRplus line probe assay in 112 M. tuberculosis isolates. Culture (MGIT960) and identification tests were performed at the Mycobacteriology Research Center of Jimma University, Jimma, Ethiopia.

RESULTS

Mutations conferring resistance to INH, RIF, and multidrug resistance were detected in 36.6% (41/112), 30.4% (34/112), and 27.7% (31/112) of M. tuberculosis isolates respectively. Among 34 RIF-resistant isolates, 82.4% (28/34) had rpoB gene mutations at S531L, 2.9% (1/34) at H526D, and 14.7% (5/34) had mutations only at wild type probes. Of 41 INH-resistant strains, 87.8% (36/41) had mutations in the katG gene at Ser315Thr1 and 9.8% (4/41) had mutations in the inhA gene at C15T. Mutations in inhA promoter region were strongly associated with INH monoresistance.

CONCLUSION

A high rate of drug resistance was commonly observed among failure cases. The most frequent gene mutations associated with the resistance to INH and RIF were observed in the codon 315 of the katG gene and codon 531 of the rpoB gene, respectively. Further studies on mutations in different geographic regions using DNA sequencing techniques are warranted to improve the kit by including more specific mutation probes in the kit.

Drug resistance patterns of Mycobacterium tuberculosis complex and associated factors among retreatment cases around Jimma, Southwest Ethiopia

Background

Information on the pattern of drug resistant tuberculosis (TB) among re-treatment cases is crucial to develop appropriate control strategies. Therefore, we conducted this study to assess the drug resistance pattern of M. tuberculosis complex (MTBC) isolates and associated factors among re-treatment cases in Jimma area, Southwest Ethiopia.

Methods

Health facility-based cross-sectional study was conducted between March 2012 and April 2013 in Jimma area, Southwest Ethiopia. We included 79 re-treatment cases selected conveniently. Socio demographic and clinical data were collected using structured questionnaire. Sputum sample processing, mycobacterial culture, isolation and drug susceptibility testing (DST) were done at Mycobacteriology Research Centre (MRC) of Jimma University. All data were registered and entered in to SPSS version 20. Crude odds ratio (COR) and adjusted odds ratios (AOR) were calculated. P-values less than 0.05 were considered statistically significant.

Results

Seventy-nine re-treatment cases included in the study; 48 (60.8 %) were males. Forty- seven (59.5 %) study participants were from rural area with the mean age of 31.67 ± 10.02 SD. DST results were available for 70 MTBC isolates. Majority (58.6 % (41/70)) isolates were resistant to at least one of the four first line drugs. The prevalence of multidrug-resistant TB (MDR-TB) was 31.4 % (22/70). Place of residence (AOR = 3.44 (95 % CI: 1.12, 10.60), duration of illness (AOR = 3.00 (95 % CI: 1.17, 10.69) and frequency of prior TB therapy (AOR = 2.99, (95 % CI: 1.01, 8.86) were significant factors for any drug resistance. Moreover, history of treatment failure was found to be associated with MDR-TB (AOR = 3.43 (95 % CI: 1.14, 10.28).

Conclusion

The overall prevalence of MDR-TB among re-treatment cases around Jimma was high. The rate of MDR-TB was higher in patients with the history of anti-TB treatment failure. Timely identification and referral of patients with the history of treatment failure for culture and DST need to be strengthened.

Echinococcosis/hydatidosis: its prevalence, economic and public health significance in Tigray region, North Ethiopia

A cross sectional study was carried out to assess the prevalence, economic and public health significance of echinococcosis/hydatidosis in Tigray Regional State, north Ethiopia. Out of 18 stray dogs euthanized and examined, three of them were found harboring the adult parasite Echinococcus granulosus in their small intestine. From 5,194 cattle examined at slaughter houses, 1146 (22.1%) of them were found harboring hydatid cyst. The majority of the infected cattle had hydatid cyst in both liver and lungs. The hydatid cyst infection in the lung, liver, kidney, heart and spleen were found to be 13%, 8.1%, 0.5%, 0.4%, and 0.1%, respectively. The estimated total annual loss from bovine hydatidosis due to offal condemnation (lungs and liver) and carcass weight loss was 25,608 Ethiopian (Eth.) Birr. The present human hydatidosis survey conducted in all six zonal hospitals of Tigray Regional State disclosed one active clinical case in Mekelle hospital during the study period. While, the retrospective data analyses of the six zonal hospitals indicated that eight cases of human hydatidosis were diagnosed since 2000. Thus echinococcosis/hydatidosis is considerably prevalent disease in cattle and it is a serious public health concern in Tigray region.