Puneet K. Dewan

Low Sensitivity of a Whole-Blood Interferon-γ Release Assay for Detection of Active Tuberculosis

The sensitivity of an interferon-gamma assay (Quantiferon-TB Gold; Cellestis) was evaluated for the detection of tuberculosis among 242 persons with suspected tuberculosis in San Francisco, California. Thirty-seven subjects had culture-confirmed tuberculosis. Excluding 1 indeterminate result, 23 (64%; 95% confidence interval, 48%-78%) of 36 subjects had positive results using the QuantiFERON-TB Gold assay. The 64% sensitivity suggests that the QuantiFERON-TB Gold assay should not be used alone to exclude active tuberculosis.

Improving tuberculosis control through public-private collaboration in India: literature review

Abstract Objective To review the characteristics of public-private mix projects in India and their effect on case notification and treatment outcomes for tuberculosis. Design Literature review. Data sources Review of surveillance records from Indian tuberculosis programme project, evaluation reports, and medical literature for public-private mix projects in India. Data extraction Project characteristics, tuberculosis case notification of new patients with sputum smear results positive for acid fast bacilli, and treatment outcome. Data synthesis Of 24 identified public-private mix projects, data were available from 14 (58%), involving private practitioners, corporations, and non-governmental organisations. In all reviewed projects, the public sector tuberculosis programme provided training and supervision of private providers. Among the five projects with available data on historical controls, case notification rates were higher after implementation of a public-private mix project. Among seven projects involving private practitioners, 2796 of 12 147 (23%) new patients positive for acid fast bacilli were attributed to private providers. Corporate based and non-governmental organisations served as the main source for tuberculosis programme services in seven project areas, detecting 9967 new patients positive for acid fast bacilli. In nine of 12 projects with data on treatment outcomes, private providers exceeded the programme target of 85% treatment success for new patients positive for acid fast bacilli. Conclusions Public-private mix activities were associated with increased case notification, while maintaining acceptable treatment outcomes. Collaborations between public and private providers of health care hold considerable potential to improve tuberculosis control in India.

High diabetes prevalence among tuberculosis cases in Kerala, India.

Background While diabetes mellitus (DM) is a known risk factor for tuberculosis, the prevalence among TB patients in India is unknown. Routine screening of TB patients for DM may be an opportunity for its early diagnosis and improved management and might improve TB treatment outcomes. We conducted a cross-sectional survey of TB patients registered from June–July 2011 in the state of Kerala, India, to determine the prevalence of DM. Methodology/Principal Findings A state-wide representative sample of TB patients in Kerala was interviewed and screened for DM using glycosylated hemoglobin (HbA1c); patients self-reporting a history of DM or those with HbA1c ≥6.5% were defined as diabetic. Among 552 TB patients screened, 243(44%) had DM – 128(23%) had previously known DM and 115(21%) were newly diagnosed - with higher prevalence among males and those aged >50years. The number needed to screen(NNS) to find one newly diagnosed case of DM was just four. Of 128 TB patients with previously known DM, 107(84%) had HbA1c ≥7% indicating poor glycemic control. Conclusions/Significance Nearly half of TB patients in Kerala have DM, and approximately half of these patients were newly-diagnosed during this survey. Routine screening of TB patients for DM using HbA1c yielded a large number of DM cases and offered earlier management opportunities which may improve TB and DM outcomes. However, the most cost-effective ways of DM screening need to be established by futher operational research.

Feasibility, acceptability, and cost of tuberculosis testing by whole-blood interferon-gamma assay.

BackgroundThe whole-blood interferon-gamma release assay (IGRA) is recommended in some settings as an alternative to the tuberculin skin test (TST). Outcomes from field implementation of the IGRA for routine tuberculosis (TB) testing have not been reported. We evaluated feasibility, acceptability, and costs after 1.5 years of IGRA use in San Francisco under routine program conditions.MethodsPatients seen at six community clinics serving homeless, immigrant, or injection-drug user (IDU) populations were routinely offered IGRA (Quantiferon-TB). Per guidelines, we excluded patients who were <17 years old, HIV-infected, immunocompromised, or pregnant. We reviewed medical records for IGRA results and completion of medical evaluation for TB, and at two clinics reviewed TB screening logs for instances of IGRA refusal or phlebotomy failure.ResultsBetween November 1, 2003 and February 28, 2005, 4143 persons were evaluated by IGRA. 225(5%) specimens were not tested, and 89 (2%) were IGRA-indeterminate. Positive or negative IGRA results were available for 3829 (92%). Of 819 patients with positive IGRA results, 524 (64%) completed diagnostic evaluation within 30 days of their IGRA test date. Among 503 patients eligible for IGRA testing at two clinics, phlebotomy was refused by 33 (7%) and failed in 40 (8%). Including phlebotomy, laboratory, and personnel costs, IGRA use cost

Inhalational Anthrax Outbreak among Postal Workers, Washington, D.C., 2001

33.67 per patient tested.ConclusionIGRA implementation in a routine TB control program setting was feasible and acceptable among homeless, IDU, and immigrant patients in San Francisco, with results more frequently available than the historically described performance of TST. Laboratory-based diagnosis and surveillance for M. tuberculosis infection is now possible.

Risk factors for treatment default among re-treatment tuberculosis patients in India, 2006.

In October 2001, four cases of inhalational anthrax occurred in workers in a Washington, D.C., mail facility that processed envelopes containing Bacillus anthracis spores. We reviewed the envelopes’ paths and obtained exposure histories and nasal swab cultures from postal workers. Environmental sampling was performed. A sample of employees was assessed for antibody concentrations to B. anthracis protective antigen. Case-patients worked on nonoverlapping shifts throughout the facility. Environmental sampling showed diffuse contamination of the facility, suggesting multiple aerosolization events. Potential workplace exposures were similar for the case-patients and the sample of workers. All nasal swab cultures and serum antibody tests were negative. Available tools could not identify subgroups of employees at higher risk for exposure or disease. Prophylaxis was necessary for all employees. To protect postal workers against bioterrorism, measures to reduce the risk of occupational exposure are necessary.

A tuberculosis outbreak in a private-home family child care center in San Francisco, 2002 to 2004.

Setting Under Indias Revised National Tuberculosis Control Programme (RNTCP), >15% of previously-treated patients in the reported 2006 patient cohort defaulted from anti-tuberculosis treatment. Objective To assess the timing, characteristics, and risk factors for default amongst re-treatment TB patients. Methodology For this case-control study, in 90 randomly-selected programme units treatment records were abstracted from all 2006 defaulters from the RNTCP re-treatment regimen (cases), with one consecutively-selected non-defaulter per case. Patients who interrupted anti-tuberculosis treatment for >2 months were classified as defaulters. Results 1,141 defaulters and 1,189 non-defaulters were included. The median duration of treatment prior to default was 81 days (25%–75% interquartile range 44–117 days) and documented retrieval efforts after treatment interruption were inadequate. Defaulters were more likely to have been male (adjusted odds ratio [aOR] 1.4, 95% confidence interval [CI] 1.2–1.7), have previously defaulted anti-tuberculosis treatment (aOR 1.3 95%CI 1.1–1.6], have previous treatment from non-RNTCP providers (AOR 1.3, 95%CI 1.0–1.6], or have public health facility-based treatment observation (aOR 1.3, 95%CI 1.1–1.6). Conclusions Amongst the large number of re-treatment patients in India, default occurs early and often. Improved pre-treatment counseling and community-based treatment provision may reduce default rates. Efforts to retrieve treatment interrupters prior to default require strengthening.

High Rates of Ofloxacin Resistance in Mycobacterium tuberculosis among Both New and Previously Treated Patients in Tamil Nadu, South India

BACKGROUND. Child care facilities are well known as sites of infectious disease transmission, and California child care facility licensure requirements include annual tuberculosis (TB) screening for on-site adults. In April 2004, we detected an adult with TB living in a private-home family child care center (child care center A). METHODS. We reviewed patient medical records and conducted a contact investigation. The investigation included all persons at the child care center, the workplace and leisure contacts of the adult patient with TB, and the household contacts of secondary case patients. Contact names were obtained through patient interviews. A positive tuberculin skin test result was defined as induration of ≥5 mm. DNA fingerprints of Mycobacterium tuberculosis isolates were analyzed. Outbreak cases were those that had matching DNA fingerprint patterns or were linked epidemiologically, if DNA fingerprint results were not available. RESULTS. Between August 2002 and July 2004, we detected 11 outbreak cases, including 9 (82%) among children (<18 years of age). All 11 outbreak patients lived or were cared for at child care center A. The 9 pediatric TB patients were young (<7 years of age), United States-born children of foreign-born parents, and 4 (44%) had positive cultures for M tuberculosis. Including isolates recovered from the 2 adult patients, all 6 M tuberculosis isolates shared identical, 7-band, DNA fingerprint patterns. The contact investigation identified 3 (33%) of the 9 pediatric cases; 2 (22%) presented with illness and 4 (44%) were detected by primary care providers during routine TB screening. Excluding case subjects, 36 (54%) of 67 named contacts had latent TB infection. CONCLUSIONS. Provider adherence to locally adapted pediatric TB screening recommendations proved critical to outbreak control. TB screening compliance by the child care center and more aggressive source-case investigation by the TB program might have prevented or abated this large pediatric TB outbreak.

Evaluation of TB Case Finding through Systematic Contact Investigation, Chhattisgarh, India

Periodic drug resistance surveillance provides useful information on trends of drug resistance and effectiveness of tuberculosis (TB) control measures. The present study determines the prevalence of drug resistance among new sputum smear positive (NSP) and previously treated (PT) pulmonary TB patients, diagnosed at public sector designated microscopy centers (DMCs) in the state of Tamil Nadu, India. In this single-stage cluster-sampling prevalence survey, 70 of 700 DMCs were randomly selected using a probability-proportional to size method. A cluster size of 24 for NSP and a varying size of 0 to 99 for PT cases were fixed for each selected DMC. Culture and drug susceptibility testing was done on Lowenstein-Jensen medium using the economic variant of proportion sensitivity test for isoniazid (INH), rifampicin (RMP), ofloxacin (OFX) and kanamycin (KAN). Human Immunodeficiency Virus (HIV) status was collected from patient records. From June 2011 to August 2012, 1524 NSP and 901 PT patients were enrolled. Any RMP resistance and any INH resistance were observed in 2.6% and 15.1%, and in 10.4% and 30% respectively in NSP and PT cases. Among PT patients, multi drug resistant TB (MDR-TB) was highest in the treatment failure (35%) group, followed by relapse (13%) and treatment after default (10%) groups. Extensively drug resistant TB (XDRTB) was seen in 4.3% of MDR-TB cases. Any OFX resistance was seen in 10.4% of NSP, 13.9% of PT and 29% of PT MDR-TB patients. The HIV status of the patient had no impact on drug resistance levels. RMP resistance was present in 2.6% of new and 15.1% of previously treated patients in Tamil Nadu. Rates of OFX resistance were high among NSP and PT patients, especially among those with MDR-TB, a matter of concern for development of new treatment regimens for TB.

Airborne infection control in India: Baseline assessment of health facilities

Rationale. Contact investigation is an established tool for early case detection of tuberculosis (TB). In India, contact investigation is not often conducted, despite national policy, and the yield of contact investigation is not well described. Objective. To determine the yield of evaluating household contacts of sputum smear-positive TB cases in Rajnandgaon district, Chhattisgarh, India. Methods. Among 14 public health care facilities with sputum smear microscopy services, home visits were conducted to identify household contacts of all registered sputum smear-positive TB cases. We used a standardized protocol to screen for clinical symptoms suggestive of active TB with additional referral for chest radiograph and sputa collection. Results. From December 2010 to May 2011, 1,556 household contacts of 312 sputum smear-positive TB cases were identified, of which 148 (9.5%) were symptomatic. Among these, 109 (73.6%) were evaluated by sputum examination resulting in 11 cases (10.1%) of sputum smear-positive TB and 4 cases (3.6%) of smear-negative TB. Household visits contributed additional 63% TB cases compared to passive case detection alone. Conclusion. A standard procedure for conducting household contact investigation identified additional TB cases in the community and offered an opportunity to initiate isoniazid chemoprophylaxis among children.