Performance of the Roche cobas MTB Assay for the Molecular Diagnosis of Pulmonary Tuberculosis in a High HIV Burden Setting.

Increased access to and improved sensitivities of methods for diagnosing Mycobacterium tuberculosis infection and detecting rifampicin and isoniazid resistance are needed. Herein, the performance of the new cobas MTB assay for use on cobas 6800/8800 Systems (Roche) was assessed and compared with two other commercial assays: RealTime MTB (Abbott), and Xpert MTB/RIF (Cepheid). Molecular PCR-based assays were conducted on sputum specimens from individuals with presumptive and confirmed tuberculosis (n = 294) from two clinical facilities in South Africa between December 2016 and October 2017. Liquid mycobacterial culture was the reference. Test sensitivities were 94.7% (95% CI, 88%-98%), 92.6% (95% CI, 85%-97%), and 91.6% (95% CI, 84%-96%) for cobas MTB, RealTime MTB, and Xpert MTB/RIF assays, respectively. cobas MTB sensitivity was unaffected by HIV coinfection (95.7%; 95% CI, 88%-99%; n = 176) and sediment testing (94.7%; 95% CI, 88%-98%). Sensitivities were 81.8% (95% CI, 60%-95%), 72.7% (95% CI, 50%-89%), and 72.7% (95% CI, 50%-89%) among smear-negative, culture-positive individuals (n = 221) for cobas MTB, RealTime MTB, and Xpert MTB/RIF assays, respectively. cobas MTB specificity was 95.7% (95% CI, 89%-99%) and 99% (95% CI, 94%-100%) among HIV coinfected and uninfected individuals, respectively. The cobas 6800/8800 system is already implemented in South Africa for high-throughput HIV viral load testing, making it suitable for integrated HIV/tuberculosis diagnostics.

Indoor air pollution from secondhand tobacco smoke, solid fuels, and kerosene in homes with active tuberculosis disease in South Africa.

OBJECTIVES: Secondhand tobacco smoke (SHS), use of solid fuels, and kerosene may play an important role in perpetuating the tuberculosis (TB) epidemic. The purpose of this study was to explore the prevalence of household air pollution (HAP) from these sources in homes of someone with TB in a high HIV-prevalence setting. A convenience sample of homes and household members participating in an ongoing active case-finding study in Matlosana district townships surrounding Klerksdorp, South Africa were included. RESULTS: We found a high prevalence of air pollution from SHS, solid fuels, and kerosene among individuals in homes with a case of prevalent active TB disease in Klerksdorp, South Africa. Adults in 40% of homes reported a daily smoker in the home, and 70% of homes had detectable air nicotine. In homes with a history of previous TB (prior to but not including the index case) as compared to those without previous TB, both SHS (83% vs. 65%, respectively) and solid/kerosene fuel use for more than 1 h/day (27% vs. 21%, respectively) were more prevalent. Larger studies are needed to estimate the risk of TB from these types of air pollution in HIV infected individuals and settings with high HIV prevalence.

Brief Report: Late Efavirenz-Induced Ataxia and Encephalopathy: A Case Series.

BACKGROUND: WHO treatment guidelines recommend efavirenz in first-line antiretroviral therapy (ART). Efavirenz commonly causes early transient neuropsychiatric adverse events. We present 20 cases with severe encephalopathy accompanied by ataxia due to efavirenz toxicity. METHODS: Consecutive HIV-infected adults taking efavirenz-containing ART admitted to Tshepong hospital, Klerksdorp, South Africa with ataxia and encephalopathy were included in this case series. RESULTS: We identified 20 women admitted to hospital with severe ataxia. All received efavirenz-based ART for a median of 2 years. All had severe ataxia and none had nystagmus. Eleven had features of encephalopathy. Median weight was 34 kg [interquartile range (IQR): 29.7-35.3]; median CD4 count 299 cells/mm (IQR: 258-300) and most (18 of 19) were virally suppressed. Eight patients had a record of prior weights and 7 of 8 showed significant weight loss with a median weight loss of 10.8 kg (IQR: 8-11.6). All cases had plasma efavirenz assays, 19 were supratherapeutic (more than twice the upper level of therapeutic range), and 15 had concentrations above the upper limit of assay detection. Ataxia resolved after withdrawal of efavirenz at a median time of 2 months (IQR: 1.25-4) and recurred in 2 of 3 patients when rechallenged. Admissions before diagnosis were frequent with 10 cases admitted previously. Three women died. CONCLUSIONS: Efavirenz toxicity may present with severe reversible ataxia often with encephalopathy years after its initiation, likely in genetic slow metabolizers. We recommend that patients whose weight is <40 kg receive lower doses of efavirenz and that therapeutic drug monitoring be considered, and efavirenz stopped in patients presenting with ataxia. Eight patients had a record of prior subsequent weights and 7 of 8 showed significant weight loss gain; median gain of 10.8 kg (IQR: 8-11.6).

The Use of Xpert MTB/Rif for Active Case Finding among TB Contacts in North West Province, South Africa.

Introduction. Tuberculosis is a major cause of morbidity and mortality especially in high HIV burden settings. Active case finding is one strategy to potentially reduce TB disease burden. Xpert MTB/Rif has recently been recommended for diagnosis of TB. Methods. Pragmatic randomized trial to compare diagnosis rate and turnaround time for laboratory testing for Xpert MTB/Rif with TB microscopy and culture in household contacts of patients recently diagnosed with TB. Results. 2464 household contacts enrolled into the study from 768 active TB index cases. 1068 (44%) were unable to give sputum, but 24 of these were already on TB treatment. 863 (53%) participants sputum samples were tested with smear and culture and 2.7% (23/863; CI: 1.62-3.78) were diagnosed with active TB. Xpert MTB/Rif was used in 515 (21%) participants; active TB was diagnosed in 1.6% (8/515; CI: 0.52-2.68). Discussion and Conclusions. Additional 31 cases were diagnosed with contact tracing of household members. When Xpert MTB/Rif is compared with culture, there is no significant difference in diagnostic yield.

Incidence of TB and HIV in prospectively followed household contacts of TB index patients in South Africa.

OBJECTIVE: To report the incidence rates of TB and HIV in household contacts of index patients diagnosed with TB. DESIGN: A prospective cohort study in the Matlosana sub-district of North West Province, South Africa. METHODS: Contacts of index TB patients received TB and HIV testing after counseling at their first household visit and were then followed up a year later, in 2010. TB or HIV diagnoses that occurred during the period were determined. RESULTS: For 2,377 household contacts, the overall observed TB incidence rate was 1.3 per 100 person years (95% CI 0.9-1.9/100py) and TB incidence for individuals who were HIV-infected and HIV seronegative at baseline was 5.4/100py (95% CI 2.9-9.0/100py) and 0.7/100py (95% CI 0.3-1.4/100py), respectively. The overall HIV incidence rate was 2.2/100py (95% CI 1.3-8.4/100py). CONCLUSIONS: In the year following a household case finding visit when household contacts were tested for TB and HIV, the incidence rate of both active TB and HIV infection was found to be extremely high. Clearly, implementing proven strategies to prevent HIV acquisition and preventing TB transmission and progression to disease remains a priority in settings such as South Africa.

High prevalence of pulmonary tuberculosis but low sensitivity of symptom screening among HIV-infected pregnant women in South Africa.

Symptom screening is a recommended component of intensified case-finding (ICF) for pulmonary tuberculosis (TB) among HIV-infected individuals. Symptomatic individuals are further investigated to either exclude or diagnose pulmonary TB, thus reducing the number of individuals requiring costly laboratory investigation. Those with laboratory evaluations negative for pulmonary TB or who lack symptoms may be eligible for antiretroviral therapy (ART) and/or TB isoniazid preventive therapy (IPT). A four-part symptom screen has been recommended by the World Health Organization (WHO) for identifying TB suspects and those unlikely to have TB. A meta-analysis of studies among HIV-infected individuals calculated a sensitivity of 90.1% for the four-part symptoms screen--of any of cough, fever, night sweats, or weight loss--among patients in clinical care, making it an effective tool for identifying most patients with TB. An important population for intensified case-finding not included in that meta-analysis was HIV-infected pregnant women. We undertook a cross-sectional survey among HIV-infected pregnant women receiving prenatal care at community clinics in South Africa. We obtained a four-symptom review and sputum smear microscopy and mycobacterial culture on all participants. Among 1415 women, 226 (16%) had a positive symptom screen, and 35 (2.5%) were newly diagnosed with culture-positive TB. Twelve were on TB treatment at the time of screening, yielding 47 (3.3%) women with prevalent TB. Symptom screening among women without known TB had a sensitivity of 28% and specificity of 84%. The poor performance of symptom screening to identify women with TB suggests that other approaches may be needed for intensified case-finding to be effective for this population.

Community-based targeted case finding for tuberculosis and HIV in household contacts of patients with tuberculosis in South Africa.

RATIONALE: South Africa has a high prevalence of tuberculosis (TB) and HIV-coinfected adults in whom TB is often diagnosed late in the course of disease. OBJECTIVES: Improved case-finding approaches for TB and HIV are needed to reduce mortality and prevent transmission. METHODS: We identified newly diagnosed index TB cases in a rural district and enrolled their households in a TB-HIV contact-tracing study. A group of randomly selected control households were enrolled to determine community prevalence of undetected TB and HIV. Field teams screened participants for TB symptoms, collected sputum specimens for smear microscopy and culture, provided HIV counseling and testing, and collected blood for CD4 testing. Participants were referred to public clinics for TB treatment and antiretroviral therapy. MEASUREMENTS AND MAIN RESULTS: We evaluated 2,843 household contacts of 727 index patients with TB and 983 randomly selected control household members. The prevalence of TB in household contacts was 6,075 per 100,000 (95% confidence interval, 5,789-6,360 per 100,000), whereas the prevalence detected in randomly selected households was 407 per 100,000 (95% confidence interval, 0-912 per 100,000; prevalence difference, 5,668 per 100,000; P < 0.001). TB detected among contacts was less likely to be smear-positive than in the index patients (6% vs. 22%; P < 0.001). Most contacts with culture-confirmed TB were asymptomatic. At least one case of undiagnosed TB was found in 141 (19%) of 727 contact versus 4 (1%) of 312 control households. HIV testing was positive in 166 (11%) of 1,568 contacts tested versus 76 (14%) of 521 control participants tested (odds ratio, 1.48; P = 0.02). CONCLUSIONS: Active case finding in TB contact households should be considered to improve TB and HIV case detection in high-prevalence settings, but sensitive diagnostic tools are necessary.