BACKGROUND
Drug-resistant TB (DR-TB) remains a major public health threat. In 2022, Uzbekistan reported 2,117 cases of DR-TB, with 69% tested for fluoroquinolone resistance. Limited information is available on the prevalence of resistance to bedaquiline, linezolid, and fluoroquinolone, which are key components of the all-oral treatment regimen for rifampicin-resistant TB in Uzbekistan.
METHODS
A retrospective study was conducted using extensive programmatic data from 2019 to 2023 in Uzbekistan. We assessed second-line drug-resistant TB (SLDR-TB) rates using phenotypic drug susceptibility testing (pDST). Demographic and clinical characteristics associated with SLDR-TB were analysed using multivariable logistic regression models based on the Allen-Cady approach.
RESULTS
In total, 2,405 patients with TB who had undergone pDST were included (median age 40 years, 47% female). The overall SLDR-TB resistance rate was 24% (95% CI 22-26). Prevalence of resistance to bedaquiline, linezolid, moxifloxacin, levofloxacin, and amikacin were respectively 3.1%, 0.8%, 15%, 13%, and 12%. Risk factors for SLDR-TB were resistance to rifampicin and/or isoniazid, exposure to clofazimine, retreatment status, contact with drug-susceptible TB case or DR-TB case, and diabetes.
CONCLUSIONS
The high prevalence of SLDR-TB is of major concern, emphasising the need for baseline pDST in RR-TB treatment. Identified risk factors can aid early detection of at-risk individuals and inform clinical practice.
In this retrospective study, we evaluated the diagnostic accuracy of molecular tests (MT) for the detection of DR‐TB, compared to the gold standard liquid‐based Drug Susceptibility Testing (DST) in Karakalpakstan.
METHODS
A total of 6,670 specimens received in the Republican TB No 1 Hospital Laboratory of Karakalpakstan between January and July 2017 from new and retreatment patients were analyzed. Samples were tested using Xpert MTB/RIF and line probe assays (LPA) for the detection of mutations associated with resistance. The sensitivity and specificity of MTs were calculated relative to results based on DST.
RESULTS
The accuracy of MT for detection of rifampicin resistance was high, with sensitivity and specificity over 98%. However, we observed reduced sensitivity of LPA for detection of resistance; 86% for isoniazid (95%CI 82‐90%), 86% for fluoroquinolones (95%CI 68‐96%), 70% for capreomycin (95%CI 46‐88%) and 23% for kanamycin (95%CI 13‐35%).
CONCLUSIONS
We show that MTs are a useful tool for rapid and safe diagnosis of DR‐TB, however, clinicians should be aware of their limitations. Although detection of rifampicin resistance was highly accurate, our data suggests that resistance mutations circulating in the Republic of Karakalpakstan for other drugs were not detected by the methods used here. This merits further investigation.
There is a need for access to clean potable water worldwide. However, almost every source of surface water in Guatemala is contaminated. This study assesses the potential exposure to water contaminants in proximity to Medecins Sans Frontieres's (MSF) chronic kidney disease clinic population in La Gomera, Guatemala during wet and dry seasons. Five municipal wells and four artisanal wells (servicing approximately 18.9% of La Gomera) were selected for their proximity to MSF La Gomera clinic to determine the presence of coliforms, physicochemical parameters, heavy metals, and pesticide residues. Water samples were collected over 3 consecutive days during La Gomera's wet season and again during the dry season. Wet season 2022: Total coliforms and Escherichia coli exceeded the acceptable limits for several artisanal wells but were not detected in municipal wells. Mercury and arsenic were detected in all wells during at least one sampling period. Dry season 2023: Total coliforms exceeded the acceptable limits for all wells and E. coli was detected in all four artisanal wells. Lead and arsenic were detected in all wells. Our results suggest that water from artisanal wells does not meet COGUANOR or WHO microbiological criteria for human consumption.
Afghanistan is affected by one of the world's longest protracted armed conflicts, frequent natural disasters, disease outbreaks and large population movements and it suffers from a high burden of tuberculosis (TB), including rifampicin-resistant TB (RR-TB). The study shows Médecins Sans Frontières' experiences with care for patients with RR-TB in Kandahar Province. We describe the uptake of RR-TB treatment, how World Health Organisation criteria for the choice between the short and an individualized regimen were implemented, and treatment outcomes.
METHODS
This is a retrospective cohort analysis of routinely collected data from RR-TB patients enrolled in care from 2016 until 2019. Descriptive analysis was performed to present characteristics of patients and treatment outcomes. Multivariable Cox analysis was performed to identify risk factors for having an unfavourable treatment outcome.
RESULTS
Out of 146 enrolled RR-TB patients, 112 (76.7%) started treatment: 41 (36.6%) and 71 (63.4%) with the short and individualized treatment regimen, respectively. Of 82 with results for fluoroquinolone susceptibility, 39 (47.6%) had fluoroquinolone-resistant TB. Seven patients with initially fluoroquinolone-resistant TB and three pregnant women started the short regimen and 18 patients eligible for the short regimen started the injectable-free individualized regimen. Overall, six-month smear and culture conversion were 98.7% and 97.1%, respectively; treatment success was 70.1%. Known initial fluoroquinolone resistance (aHR 3.77, 95%CI:1.53-9.27) but not choice of regimen predicted having an unfavourable outcome.
CONCLUSION
Even though criteria for the choice of treatment regimen were not applied strictly, we have achieved acceptable outcomes in this cohort. To expand RR-TB care, treatment regimens should fit provision at primary health care level and take patient preferences into account.
IMPORTANCE
The importance of this report is that it provides further support for WHO’s recent recommendation that fresh stool is an acceptable sample for GeneXpert TB testing in children, especially small children who often cannot produce an adequate sputum sample. Diagnosing TB in this age group is difficult, and many cases are missed, leading to unacceptable rates of TB illness and death. In our large cohort of children from Dushanbe, Tajikistan, the GeneXpert stool test was positive in 69% of proven cases of TB, and there were very few false-positive tests. We also showed that this diagnostic strategy was feasible to implement in a low-middle-income country with an inefficient health care delivery system. We hope that many more programs will adopt this form of diagnosing TB in children.