Performance of the GenoType MTBDRsl in a programmatic setting, South Africa.

BACKGROUND: The GenoType MTBDRsl v2 is a molecular test designed for the rapid detection of resistance to second-line anti-TB drugs in Mycobacterium tuberculosis complex (MTBC).OBJECTIVE: To assess the use of MTBDRsl in a programmatic setting and to describe the resistance patterns in a high HIV-TB-endemic area in South Africa.METHODS: We performed a retrospective data analysis of all MTBDRsl results in patients with newly diagnosed rifampicin-resistant TB (RR-TB). We compared its performance on direct testing of smear-positive and smear-negative specimens. Results were examined to observe the detected resistance-conferring mutations.RESULTS: Of 1873 RR-TB/multidrug-resistant TB (MDR-TB), 37.4% were smear-negative and 62.5% were smear-positive. Among smear-negative specimens, the MTBDRsl showed an inconclusive rate of 61.2%, while the inconclusive rate from smear-positive specimens was 6.6%. The most common mutation observed in case of fluoroquinolone resistance occurred at the gyrA gene, codon 90 (A90V) (61/158, 38.6%), and the most common mutation in injectable aminoglycoside resistance occurred in the rrs region, A1401G (71/108, 65.7%).CONCLUSION: In HIV-TB-prevalent settings, routine use of the MTBDRsl is more effective when performed directly on smear-positive specimens. In view of currently used injectable-free regimens, this test requires revision.

Extensively drug-resistant tuberculosis 'hotspots' and sociodemographic associations in Durban, South Africa.

In KwaZulu-Natal, South Africa, the incidence of extensively drug-resistant tuberculosis (XDR-TB) is driven by the transmission of resistant strains. As data suggest that cases may be spatially clustered, we sought to identify 'hotspots' and describe these communities. We enrolled XDR-TB patients diagnosed from 2011 to 2014 in eThekwini. Global positioning system (GPS) coordinates for participant homes were collected and hotspots were identified based on population-adjusted XDR-TB incidence. The sociodemographic features of hotspots were characterised using census data. For a subset of participants, we mapped non-home XDR-TB congregate locations and compared these with results including only homes. Among 132 participants, 75 (57%) were female and 87 (66%) lived in urban or suburban locations. Fifteen of 197 census tracts were identified as XDR-TB hotspots with ≥95% confidence. Four spatial mapping methods identified one large hotspot in northeastern eThekwini. Hotspot communities had higher proportions of low educational attainment (12% vs. 9%) and unemployment (29.3% vs. 20.4%), and lower proportion of homes with flush toilets (36.4% vs. 68.9%). The case density shifted towards downtown Durban when congregate locations (e.g., workplaces) for 43 (33%) participants were mapped. In eThekwini, XDR-TB case homes were clustered into hotspots with more poverty indicators than non-hotspots. Prevention efforts targeting hotspot communities and congregate settings may be effective in reducing community transmission. .

Impact of gyrB and eis Mutations in Improving Detection of Second-Line-Drug Resistance among Mycobacterium tuberculosis Isolates from Georgia.

The country of Georgia has a high burden of multi- and extensively drug-resistant tuberculosis (XDR-TB). To evaluate whether mutations in gyrB and eis genes increased the sensitivity of detection of phenotypic resistance to ofloxacin and kanamycin or capreomycin compared to use of the first-generation MTBDRsl assay alone, which tests for mutations in gyrA and rrs genes, a retrospective study of stored Mycobacterium tuberculosis isolates was performed. All isolates underwent DNA sequencing of resistance-determining regions. Among 112 M. tuberculosis isolates with DNA extraction data, targeted sequencing was successfully performed for each gene as follows: for gyrA, 98% sensitivity; for gyrB, 96%; for rrs, 93%; for the eis gene and its promoter, 93%. The specificity and hence the positive predictive value of gyrA and gyrB mutations for detecting ofloxacin resistance were 100%. The addition of gyrB mutations increased the sensitivity of phenotypic ofloxacin resistance detection by 13% (75% to 88%). All rrs resistance-conferring mutations were A1401G, and this mutation had low sensitivity (40% and 18%) and high specificity (95% and 100%) in predicting phenotypic capreomycin and kanamycin resistance, respectively. The eis C-14T mutation increased the sensitivity of phenotypic kanamycin resistance detection by 9% (18% to 27%) and was found solely in kanamycin phenotypic resistance isolates. Our data showed that the inclusion of eis C-14T and gyrB mutations in addition to rrs and gyrA mutations improves the sensitivity of detection of phenotypic ofloxacin and kanamycin resistance, respectively.

Diabetes mellitus and extrapulmonary tuberculosis: site distribution and risk of mortality.

Scarce data exist on the relationship between diabetes and extrapulmonary tuberculosis (EPTB). We evaluated whether diabetes impacts site of TB and risk of death in patients with EPTB. We evaluated a cohort of TB cases from the state of Georgia between 2009 and 2012. Patients aged ⩾16 years were classified by diabetes status according to medical records. Site of EPTB was determined by culture and/or state TB classification. Death was defined by all-cause mortality. Of 1325 eligible reported TB cases, 369 (27·8%) had any EPTB including 258 (19·5%) with only EPTB and 111 (8·4%) with pulmonary TB and EPTB. Of all TB cases, 158 had diabetes (11·9%). In multivariable analysis, the odds of any EPTB was similar in patients with and without diabetes [adjusted odds ratio 1·04, 95% confidence interval (CI) 0·70-1·56]. The risk of death was 23·8% in patients with EPTB and diabetes vs. 9·8% in those with no diabetes (P < 0·01); after adjusting for covariates the difference was not significant (aRR 1·19, 95% CI 0·54-2·63). Diabetes was common in patients with EPTB and risk of death was high. Improved understanding of the relationship between diabetes and EPTB is critical to determine the extent that diabetes affects TB diagnosis and clinical management.

Diabetes mellitus is associated with cavities, smear grade, and multidrug-resistant tuberculosis in Georgia.

SETTING: National tuberculosis (TB) treatment facility in the country of Georgia. OBJECTIVE: To determine the prevalence of diabetes mellitus (DM) and pre-DM among patients with TB using glycosylated-hemoglobin (HbA1c), and to estimate the association between DM and clinical characteristics and response to anti-tuberculosis treatment. DESIGN: A cohort study was conducted from 2011 to 2014 at the National Centre for TB and Lung Disease in Tbilisi. Patients aged ⩾ 35 years with pulmonary TB were included. HbA1c was used to define DM (⩾ 6.5%), pre-DM (⩾ 5.7-6.4%), and no DM (<5.7%). Interviews and medical chart abstraction were performed. Regression analyses estimated associations between DM and 1) baseline TB characteristics and 2) anti-tuberculosis treatment outcomes. RESULTS: A total of 318 newly diagnosed patients with TB were enrolled. The prevalence of DM and pre-DM was 11.6% and 16.4%, respectively. In multivariable analyses, patients with TB-DM had more cavitation (adjusted OR [aOR] 2.26), higher smear grade (aOR 2.37), and more multidrug-resistant TB (MDR-TB) (aOR 2.27) than patients without DM. The risk of poor anti-tuberculosis treatment outcomes was similar among patients with and those without DM (28.1% vs. 23.6%). CONCLUSION: DM and pre-DM were common among adults with newly diagnosed pulmonary TB in Tbilisi, Georgia, and DM was associated with more clinical symptoms, and MDR-TB, at presentation.

Drug resistance beyond extensively drug-resistant tuberculosis: individual patient data meta-analysis.

The broadest pattern of tuberculosis (TB) drug resistance for which a consensus definition exists is extensively drug-resistant (XDR)-TB. It is not known if additional drug resistance portends worsened patient outcomes. This study compares treatment outcomes of XDR-TB patients with and without additional resistance in order to explore the need for a new definition. Individual patient data on XDR-TB outcomes were included in a meta-analysis comparing outcomes between XDR alone and three nonmutually exclusive XDR-TB patient groups: XDR plus resistance to all the second-line injectables (sli) and capreomycin and kanamycin/amikacin (XDR+2sli) XDR plus resistance to second-line injectables and to more than one group 4 drug, i.e. ethionamide/protionamide, cycloserine/terizidone or para-aminosalicylic acid (XDR+sliG4) and XDR+sliG4 plus resistance to ethambutol and/or pyrazinamide (XDR+sliG4EZ). Of 405 XDR-TB cases, 301 were XDR alone, 68 XDR+2sli, 48 XDR+sliG4 and 42 XDR+sliG4EZ. In multivariate analysis, the odds of cure were significantly lower in XDR+2sli (adjusted OR 0.4, 95% CI 0.2-0.8) compared to XDR alone, while odds of failure and death were higher in all XDR patients with additional resistance (adjusted OR 2.6-2.8). Patients with additional resistance beyond XDR-TB showed poorer outcomes. Limitations in availability, accuracy and reproducibility of current drug susceptibility testing methods preclude the adoption of a useful definition beyond the one currently used for XDR-TB.

Integrated, home-based treatment for MDR-TB and HIV in rural South Africa: an alternate model of care.

SETTING: Treatment outcomes for multidrug-resistant tuberculosis (MDR-TB) in South Africa have suffered as centralized, in-patient treatment programs struggle to cope with rising prevalence and human immunodeficiency virus (HIV) co-infection rates. A new treatment model is needed to expand treatment capacity and improve MDR-TB and HIV outcomes. OBJECTIVE: To describe the design and preliminary results of an integrated, home-based MDR-TB-HIV treatment program created in rural KwaZulu-Natal. METHOD: In 2008, a decentralized center was established to provide out-patient MDR-TB and HIV treatment. Nurses, community health workers and family supporters have been trained to administer injections, provide adherence support and monitor adverse reactions in patients' homes. Physicians assess clinical response, adherence and the severity of adverse reactions to MDR-TB and HIV treatment at monthly follow-up visits. Treatment outcomes are assessed by monthly cultures and CD4 and viral load every 6 months. RESULTS: Of 80 patients initiating MDR-TB treatment from February 2008 to April 2010, 66 were HIV-co-infected. Retention has been high (only 5% defaults, 93% of visits attended), and preliminary outcomes have been favorable (77% cured/still on treatment, 82% undetectable viral load). Few patients have required escalation of care (9%), had severe adverse events (8%) or died (6%). CONCLUSION: Integrated, home-based treatment for MDR-TB and HIV is a promising treatment model to expand capacity and achieve improved outcomes in rural, resource-poor and high HIV prevalent settings.

Risk factors for mortality among MDR- and XDR-TB patients in a high HIV prevalence setting.

SETTING: Recent studies suggest that the prevalence of drug-resistant tuberculosis (TB) in sub-Saharan Africa may be rising. This is of concern, as human immunodeficiency virus (HIV) co-infection in multidrug-resistant (MDR) and extensively drug-resistant (XDR) TB has been associated with exceedingly high mortality rates. OBJECTIVE: To identify risk factors associated with mortality in MDR- and XDR-TB patients co-infected with HIV in South Africa. DESIGN: Case-control study of patients who died of all causes within 2 years of diagnosis with MDR- or XDR-TB. RESULTS: Among 123 MDR-TB patients, 78 (63%) died following diagnosis. CD4 count ≤ 50 (HR 4.64, P = 0.01) and 51-200 cells/mm(3) (HR 4.17, P = 0.008) were the strongest independent risk factors for mortality. Among 139 XDR-TB patients, 111 (80%) died. CD4 count ≤ 50 cells/mm(3) (HR 4.46, P = 0.01) and resistance to all six drugs tested (HR 2.54, P = 0.04) were the principal risk factors. Use of antiretroviral therapy (ART) was protective (HR 0.34, P = 0.009). CONCLUSIONS: Mortality due to MDR- and XDR-TB was associated with greater degree of immunosuppression and drug resistance. Efforts to reduce mortality must focus on preventing the amplification of resistance by strengthening TB treatment programs, as well as reducing the pool of immunosuppressed HIV-infected patients through aggressive HIV testing and ART initiation.

Household contact investigation of multidrug-resistant and extensively drug-resistant tuberculosis in a high HIV prevalence setting.

SETTING: Multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis (TB) are now a nationwide epidemic in South Africa. Epidemiological data suggest nosocomial transmission as the primary route of spread; however, transmission among household contacts has not yet been investigated. OBJECTIVE: To determine the incidence rates of MDR- and XDR-TB among household contacts of MDR- and XDR-TB index cases diagnosed between January 2005 and September 2008 in a high human immunodeficiency virus prevalence setting. DESIGN: Prospective, observational study evaluating adult household contacts for active TB by culture and drug susceptibility testing at index case diagnosis and again 1 year later. Outcomes were incidence and time to diagnosis of MDR- and XDR-TB. RESULTS: A total of 1766 contacts of 221 MDR-TB and 287 XDR-TB index cases were screened. Of 793 contacts of MDR-TB index cases, 14 (1.8%) were diagnosed with MDR-TB (incidence 1765/100 000); 19 (2.0%) of 973 XDR-TB contacts had XDR-TB (incidence 1952/100 000). Median time to diagnosis of household cases was 70 days (interquartile range 57-89). CONCLUSION: Incidence rates of MDR- and XDR-TB among household contacts were extremely high, with most secondary cases occurring shortly after the diagnosis of the index case. Active case finding of drug-resistant TB is a high-yield public health activity and must be a priority, as early diagnosis may stem further disease spread and improve survival.

Extensively drug-resistant tuberculosis in children with human immunodeficiency virus in rural South Africa.

SETTING: Extensively drug-resistant tuberculosis (XDR-TB) has been documented worldwide, but reports of XDR-TB in children are extremely limited. OBJECTIVE: To report the characteristics of pediatric XDR-TB patients in rural South Africa. DESIGN: We retrospectively reviewed children with sputum culture-confirmed XDR-TB from Tugela Ferry, South Africa, from January 2006 to December 2007. Demographic, clinical and microbiologic data were abstracted from medical records. RESULTS: Four children aged 6-8 years with XDR-TB were reviewed. Two had previous histories of TB. All were human immunodeficiency virus (HIV) infected orphans; three received highly active antiretroviral therapy (HAART) before XDR-TB diagnosis. All had clinical and radiographic improvement and sputum culture conversion while on standardized XDR-TB treatment and HAART. Two tolerated concomitant XDR-TB and HIV treatment well. Two experienced neuropsychiatric side effects related to cycloserine. All have survived >24 months and all were cured. Prior to XDR-TB diagnosis, the children had resided in the hospital's pediatric ward for a median of 8 months (range 5-17), including a 3-month overlapping period. CONCLUSIONS: XDR-TB is a microbiologic diagnosis that, even with HIV co-infection, can be successfully identified. Concurrent XDR-TB and HIV therapy is feasible and effective in children, although more research is needed into potential overlapping toxicities. Nosocomial transmission is suggested, calling for infection control policies in pediatric wards.

High treatment failure and default rates for patients with multidrug-resistant tuberculosis in KwaZulu-Natal, South Africa, 2000-2003.

SETTING: Multidrug-resistant tuberculosis (MDR-TB) has emerged as a significant public health threat in South Africa. OBJECTIVE: To describe treatment outcomes and determine risk factors associated with unfavorable outcomes among MDR-TB patients admitted to the provincial TB referral hospital in KwaZulu-Natal Province, South Africa. DESIGN: Retrospective observational study of MDR-TB patients admitted from 2000 to 2003. RESULTS: Of 1209 MDR-TB patients with documented treatment outcomes, 491 (41%) were cured, 35 (3%) completed treatment, 208 (17%) failed treatment, 223 (18%) died and 252 (21%) defaulted. Of the total number of patients with known human immunodeficiency virus (HIV) status, 52% were HIV-infected. Treatment failure, death and default each differed in their risk factors. Greater baseline resistance (aOR 2.3-3.0), prior TB (aOR 1.7), and diagnosis in 2001, 2002 or 2003 (aOR 1.9-2.3) were independent risk factors for treatment failure. HIV co-infection was a risk factor for death (aOR 5.6), and both HIV (aOR 2.0) and male sex (aOR 1.9) were risk factors for treatment default. CONCLUSION: MDR-TB treatment outcomes in KwaZulu-Natal were substantially worse than those published from other MDR-TB cohorts. Interventions such as concurrent antiretroviral therapy and decentralized MDR-TB treatment should be considered to improve MDR-TB outcomes in this high HIV prevalence setting.

Capillary tube immunological assay for staphylococcal enterotoxins.

A simple assay is reported in which 1 mug of staphylococcal enterotoxins A, B, and D per ml was detected in less than 1 hr. Interfacial reaction of antisera and enterotoxin solutions in a 1-ml internal diameter capillary tube allowed rapid detection of sera type.