Thuli Mthiyane

A Four-Month Gatifloxacin-Containing Regimen for Treating Tuberculosis

BACKGROUND Shortening the course of treatment for tuberculosis would be a major improvement for case management and disease control. This phase 3 trial assessed the efficacy and safety of a 4-month gatifloxacin-containing regimen for treating rifampin-sensitive pulmonary tuberculosis. METHODS We conducted a noninferiority, randomized, open-label, controlled trial involving patients 18 to 65 years of age with smear-positive, rifampin-sensitive, newly diagnosed pulmonary tuberculosis in five sub-Saharan African countries. A standard 6-month regimen that included ethambutol during the 2-month intensive phase was compared with a 4-month regimen in which gatifloxacin (400 mg per day) was substituted for ethambutol during the intensive phase and was continued, along with rifampin and isoniazid, during the continuation phase. The primary efficacy end point was an unfavorable outcome (treatment failure, recurrence, or death or study dropout during treatment) measured 24 months after the end of treatment, with a noninferiority margin of 6 percentage points, adjusted for country. RESULTS A total of 1836 patients were assigned to the 4-month regimen (experimental group) or the standard regimen (control group). Baseline characteristics were well balanced between the groups. At 24 months after the end of treatment, the adjusted difference in the risk of an unfavorable outcome (experimental group [21.0%] minus control group [17.2%]) in the modified intention-to-treat population (1356 patients) was 3.5 percentage points (95% confidence interval, -0.7 to 7.7). There was heterogeneity across countries (P=0.02 for interaction, with differences in the rate of an unfavorable outcome ranging from -5.4 percentage points in Guinea to 12.3 percentage points in Senegal) and in baseline cavitary status (P=0.04 for interaction) and body-mass index (P=0.10 for interaction). The standard regimen, as compared with the 4-month regimen, was associated with a higher dropout rate during treatment (5.0% vs. 2.7%) and more treatment failures (2.4% vs. 1.7%) but fewer recurrences (7.1% vs. 14.6%). There was no evidence of increased risks of prolongation of the QT interval or dysglycemia with the 4-month regimen. CONCLUSIONS Noninferiority of the 4-month regimen to the standard regimen with respect to the primary efficacy end point was not shown. (Funded by the Special Program for Research and Training in Tropical Diseases and others; ClinicalTrials.gov number, NCT00216385.).

Effect of standard tuberculosis treatment on plasma cytokine levels in patients with active pulmonary tuberculosis

Background Sputum Mycobacterium tuberculosis (Mtb) culture is commonly used to assess response to antibiotic treatment in individuals with pulmonary tuberculosis (TB). Such techniques are constrained by the slow growth rate of Mtb, and more sensitive methods to monitor Mtb clearance are needed. The goal of this study was to evaluate changes in plasma cytokines in patients undergoing treatment for TB as a means of identifying candidate host markers associated with microbiologic response to therapy. Methods Twenty-four plasma cytokines/chemokines were measured in 42 individuals diagnosed with active pulmonary TB, 52% were HIV co-infected. Individuals, undergoing a 26-week standard TB treatment, were followed longitudinally over 18 months and measurements were associated with HIV status and rates of sputum culture conversion. Results Plasma concentrations of interferon-inducible protein-10 (IP-10) and vascular endothelial growth factor (VEGF) were significantly reduced upon TB treatment, regardless of HIV status. By the end of treatment, IP-10 concentrations were significantly lower in HIV negative individuals when compared to HIV-positive individuals (p = 0.02). Moreover, in HIV negative patients, plasma VEGF concentrations, measured as early as 2-weeks post TB treatment initiation, positively correlated with the time of sputum conversion (p = 0.0017). No significant changes were observed in other studied immune mediators. Conclusions These data suggest that VEGF plasma concentration, measured during early TB treatment, could represent a surrogate marker to monitor sputum culture conversion in HIV uninfected individuals.

Transmission of Extensively Drug-Resistant Tuberculosis in South Africa.

BACKGROUND Drug‐resistant tuberculosis threatens recent gains in the treatment of tuberculosis and human immunodeficiency virus (HIV) infection worldwide. A widespread epidemic of extensively drug‐resistant (XDR) tuberculosis is occurring in South Africa, where cases have increased substantially since 2002. The factors driving this rapid increase have not been fully elucidated, but such knowledge is needed to guide public health interventions. METHODS We conducted a prospective study involving 404 participants in KwaZulu‐Natal Province, South Africa, with a diagnosis of XDR tuberculosis between 2011 and 2014. Interviews and medical‐record reviews were used to elicit information on the participants’ history of tuberculosis and HIV infection, hospitalizations, and social networks. Mycobacterium tuberculosis isolates underwent insertion sequence (IS)6110 restriction‐fragment–length polymorphism analysis, targeted gene sequencing, and whole‐genome sequencing. We used clinical and genotypic case definitions to calculate the proportion of cases of XDR tuberculosis that were due to inadequate treatment of multidrug‐resistant (MDR) tuberculosis (i.e., acquired resistance) versus those that were due to transmission (i.e., transmitted resistance). We used social‐network analysis to identify community and hospital locations of transmission. RESULTS Of the 404 participants, 311 (77%) had HIV infection; the median CD4+ count was 340 cells per cubic millimeter (interquartile range, 117 to 431). A total of 280 participants (69%) had never received treatment for MDR tuberculosis. Genotypic analysis in 386 participants revealed that 323 (84%) belonged to 1 of 31 clusters. Clusters ranged from 2 to 14 participants, except for 1 large cluster of 212 participants (55%) with a LAM4/KZN strain. Person‐to‐person or hospital‐based epidemiologic links were identified in 123 of 404 participants (30%). CONCLUSIONS The majority of cases of XDR tuberculosis in KwaZulu‐Natal, South Africa, an area with a high tuberculosis burden, were probably due to transmission rather than to inadequate treatment of MDR tuberculosis. These data suggest that control of the epidemic of drug‐resistant tuberculosis requires an increased focus on interrupting transmission. (Funded by the National Institute of Allergy and Infectious Diseases and others.)

Use of a WHO-recommended algorithm to reduce mortality in seriously ill patients with HIV infection and smear-negative pulmonary tuberculosis in South Africa: an observational cohort study

BACKGROUND In 2007, WHO released revised recommendations and an algorithm for the diagnosis and treatment of smear-negative pulmonary tuberculosis in seriously ill people living with HIV/AIDS. We aimed to assess the effect of the recommendations on clinical outcome in patients in South Africa. METHODS We enrolled seriously ill patients (aged ≥15 years) with HIV infection and suspected smear-negative pulmonary tuberculosis from three hospitals in KwaZulu-Natal, South Africa. Patients were consecutively enrolled into two cohorts: the first cohort was managed according to standard practice, and the second according to the WHO-recommended algorithm. The primary endpoints were rates of continued stay in hospital at 7 days after admission and survival at 8 weeks after admission. FINDINGS 338 patients were enrolled in the standard practice cohort between August, 2008, and February, 2009, and 187 were enrolled in the algorithm cohort between March, 2009, and December, 2009. 7 days after hospital admission, 27% (n=50) of patients in the algorithm cohort were still in hospital, compared with 38% (n=130) in the standard practice cohort (rate ratio 0·70, 95% CI 0·53-0·91; p=0·009). 8 weeks after admission, 83% (n=156) of patients in the algorithm cohort were alive, compared with 68% (n=230) in the standard practice cohort (1·23, 1·11-1·35; p=0·0001), with effect modified by hospital location. INTERPRETATION In seriously ill patients with HIV infection and suspected smear-negative pulmonary tuberculosis, early antituberculosis treatment according to the WHO algorithm could significantly reduce mortality in South Africa. FUNDING US Presidents Emergency Plan for AIDS Relief.

Incidence and geographic distribution of extensively drug-resistant tuberculosis in KwaZulu-Natal Province, South Africa

South Africa is experiencing a widespread drug-resistant tuberculosis epidemic, although data are limited regarding the current situation. This study finds that the extensively drug-resistant tuberculosis (XDR-TB) incidence in KwaZulu-Natal increased to 3.5 cases/100,000 (776 cases) in 2011-2012. XDR-TB cases are widely distributed geographically, with the majority of districts experiencing a rise in incidence.

Assessing the utility of Xpert® MTB/RIF as a screening tool for patients admitted to medical wards in South Africa

Many hospital inpatients in South Africa have undiagnosed active and drug-resistant tuberculosis (TB). Early detection of TB is essential to inform immediate infection control actions to minimize transmission risk. We assessed the utility of Xpert® MTB/RIF (GeneXpert) as a screening tool for medical admissions at a large public hospital in South Africa. Consecutive adult patients admitted to medical wards between March-June 2013 were enrolled; sputum specimens were collected and tested by GeneXpert, smear microscopy, and culture. Chest X-rays (CXRs) were conducted as standard care for all patients admitted. We evaluated the proportion of patients identified with TB disease through each diagnostic method. Among enrolled patients whose medical charts were available for review post-discharge, 61 (27%) were diagnosed with TB; 34 (56% of diagnosed TB cases) were GeneXpert positive. When patients in whom TB was identified by other means were excluded, GeneXpert yielded only four additional TB cases. However, GeneXpert identified rifampicin-resistant TB in one patient, who was initially diagnosed based on CXR. The utility of GeneXpert for TB screening was limited in an institution where CXR is conducted routinely and which serves a population in which TB and TB/HIV co-infection are highly prevalent, but it allowed for rapid detection of rifampicin resistance.

Spatial distribution of extensively drug-resistant tuberculosis (XDR TB) patients in KwaZulu-Natal, South Africa.

Background KwaZulu-Natal province, South Africa, has among the highest burden of XDR TB worldwide with the majority of cases occurring due to transmission. Poor access to health facilities can be a barrier to timely diagnosis and treatment of TB, which can contribute to ongoing transmission. We sought to determine the geographic distribution of XDR TB patients and proximity to health facilities in KwaZulu-Natal. Methods We recruited adults and children with XDR TB diagnosed in KwaZulu-Natal. We calculated distance and time from participants’ home to the closest hospital or clinic, as well as to the actual facility that diagnosed XDR TB, using tools within ArcGIS Network analyst. Speed of travel was assigned to road classes based on Department of Transport regulations. Results were compared to guidelines for the provision of social facilities in South Africa: 5km to a clinic and 30km to a hospital. Results During 2011–2014, 1027 new XDR TB cases were diagnosed throughout all 11 districts of KwaZulu-Natal, of whom 404 (39%) were enrolled and had geospatial data collected. Participants would have had to travel a mean distance of 2.9 km (CI 95%: 1.8–4.1) to the nearest clinic and 17.6 km (CI 95%: 11.4–23.8) to the nearest hospital. Actual distances that participants travelled to the health facility that diagnosed XDR TB ranged from <10 km (n = 143, 36%) to >50 km (n = 109, 27%), with a mean of 69 km. The majority (77%) of participants travelled farther than the recommended distance to a clinic (5 km) and 39% travelled farther than the recommended distance to a hospital (30 km). Nearly half (46%) of participants were diagnosed at a health facility in eThekwini district, of whom, 36% resided outside the Durban metropolitan area. Conclusions XDR TB cases are widely distributed throughout KwaZulu-Natal province with a denser focus in eThekwini district. Patients travelled long distances to the health facility where they were diagnosed with XDR TB, suggesting a potential role for migration or transportation in the XDR TB epidemic.

Assessing Local Risk of Rifampicin-Resistant Tuberculosis in KwaZulu-Natal, South Africa Using Lot Quality Assurance Sampling

Background KwaZulu-Natal (KZN) has the highest burden of notified multidrug-resistant tuberculosis (MDR TB) and extensively drug-resistant (XDR) TB cases in South Africa. A better understanding of spatial heterogeneity in the risk of drug-resistance may help to prioritize local responses. Methods Between July 2012 and June 2013, we conducted a two-way Lot Quality Assurance Sampling (LQAS) study to classify the burden of rifampicin (RIF)-resistant TB among incident TB cases notified within the catchment areas of seven laboratories in two northern and one southern district of KZN. Decision rules for classification of areas as having either a high- or low-risk of RIF resistant TB (based on proportion of RIF resistance among all TB cases) were based on consultation with local policy makers. Results We classified five areas as high-risk and two as low-risk. High-risk areas were identified in both Southern and Northern districts, with the greatest proportion of RIF resistance observed in the northernmost area, the Manguzi community situated on the Mozambique border. Conclusion Our study revealed heterogeneity in the risk of RIF resistant disease among incident TB cases in KZN. This study demonstrates the potential for LQAS to detect geographic heterogeneity in areas where access to drug susceptibility testing is limited.

1474Genotypic Characterization of pncA Gene in Patients with Multidrug-resistant Tuberculosis from South Africa

Rationale: Pyrazinamide (PZA) is an essential component of empiric firstand second-line tuberculosis (TB) treatment regimens. However, PZA drug susceptibility testing (DST) is difficult to perform and not routinely available. Genetic mutations in the pncA gene of Mycobacterium tuberculosis (Mtb) commonly confer PZA resistance, but limited data on the prevalence and diversity of these mutations are available from clinical populations of TB patients. We sequenced pncA to estimate PZA resistance among MDR and XDR TB patients in KwaZulu-Natal province, South Africa. Methods: We prospectively enrolled 206 MDR TB and 377 XDR TB patients from September 2011 to September 2014. Sputum collected from each participant underwent mycobacterial culture and DST for isoniazid (H), rifampin (R), streptomycin (S), kanamycin (Km) and ofloxocin (Ofx). We extracted DNA from pure Mtb isolates and performed targeted sequencing of the pncA gene, characterizing the proportion, frequency and structure of polymorphisms. Results: To date, targeted sequencing has been completed for 314 isolates from 80 MDR TB (16 resistant to HR 20 different mutations were seen among MDR TB subjects, of which, only 7 were seen in more than one participant. Among XDR TB participants, one mutation (insertion of cytosine after the 456 locus) was present in 166 (71%), consistent with the clonality of XDR TB patients in KwaZulu-Natal. Conclusion: Nearly 70% of MDR TB and nearly all XDR TB participants had pncA mutations, and likely PZA resistance, in our cohort. A wide diversity of mutations was seen. Most mutations were singlets, suggesting acquisition of mutations de novo, perhaps due to empiric use. One specific mutation was common among XDR TB participants, but it occurred in conjunction with a specific RFLP genotype associated with clonal expansion. Given the difficulty in determining PZA susceptibility, characterizing pncA mutations may provide important data for developing rapid genotypic PZA susceptibility assays. BACKGROUND • South Africa has one of the highest incidence rates of multidrug-resistant tuberculosis (MDR TB) and extensively drug-resistant tuberculosis (XDR TB) with high rates of HIV co-infection. • Pyrazinamide (PZA) is used empirically in drug-resistant TB treatment regimens. • Precise acidic conditions are required in vitro to conduct PZA drug susceptibility testing (DST). However, acidic environments inhibit the growth of Mycobacterium tuberculosis (Mtb) bacilli. • Therefore, conventional PZA DST is difficult to perform in vitro and not widely available. • Gene sequencing is an effective method to identify mutations associated with resistance for some firstand second-line anti-TB drugs. • Genetic mutations in the pncA gene of Mtb typically confer resistance to PZA. However data on the frequency and diversity of pncA mutations is limited. • Thus, the actual prevalence of PZA resistance in patients with TB and drug-resistant TB is unknown. Funding: NIH/NIAID R01AI087465 [PI Neel Gandhi] and NIH/NIAID R01AI089349 [PI Neel Gandhi] Contact: Salim Allana, MD, MPH; salim.allana@emory.edu SETTING • Study site: KwaZulu-Natal province, South Africa, which has a population of 10.2 million. • TB incidence rate is nearly 1,100 per 100,000 population, and more than 80% of TB cases are HIV co-infected. • In 2012, MDR TB incidence was 45 cases/100,000 population and XDR TB incidence was 3.1 cases/100,000 population. • The HIV prevalence among adults (15-49 years of age) is 16.8%. • MDR TB patients receive standardized second-line treatment which includes PZA, ethambutol, kanamycin, moxifloxacin, terizidone, and ethionamide. • XDR TB patients receive a similar regimen, except that capreomycin, moxifloxacin and PAS replace kanamycin. • DST testing to evaluate PZA susceptibility is not routinely performed in this setting. OBJECTIVE Among MDR and XDR TB subjects in KwaZulu-Natal province, South Africa: • To characterize the frequency and diversity of polymorphisms in the pncA gene. • To estimate the prevalence of pyrazinamide resistance.