Michael E. Kimerling

Long-Term Molecular Analysis of Tuberculosis Strains in Alabama, a State Characterized by a Largely Indigenous, Low-Risk Population

ABSTRACT With a tuberculosis case detection rate of 5.9 per 100,000 population in 2001, Alabama ranked twelfth highest in the United States. However, cases among foreign-born and human immunodeficiency virus-infected individuals remain low in Alabama. To understand the endemic statewide disease pattern, tuberculosis strains were studied for clustering in a long-term population-based study from January 1994 to May 2000. IS6110 restriction fragment length polymorphism analysis was performed for 1,834 strains. Spoligotyping was used as a secondary typing method for the 37% of isolates displaying a restriction fragment length polymorphism pattern with <6 IS6110 copies. A total of 721 (41%) patients provided isolates that composed 114 clusters, each containing isolates from 2 to 136 patients, suggesting that recent transmission accounted for 35% of tuberculosis cases. Demographic, behavioral, and clinical characteristics of patients with clustered versus nonclustered isolates stratified by low-copy-number strains (<6 IS6110 copies) versus high-copy-number strains (≥6 IS6110 copies) were evaluated. Younger age, black race, a history of alcohol abuse, and homelessness were predictors of clustering of low-copy-number, strains and younger age, urban residency, alcohol abuse, homelessness, noninjection drug use, and a history of incarceration and/or cavitary disease were predictors of clustering of high-copy-number strains. By identifying local characteristics of tuberculosis clustering through molecular fingerprinting, control programs can distribute their limited resources to impact the transmission of tuberculosis in high-risk populations and evaluate strain distribution across geographical areas.

Childhood tuberculosis in Alabama: epidemiology of disease and indicators of program effectiveness, 1983 to 1993.

An 11-year review of childhood tuberculosis in Alabama was made in order to define indicators of program effectiveness in interrupting community transmission. Minority (nonwhite) children, 96% of whom were black, had the highest risk of disease (odds ratio, 5.5; 95% confidence interval, 3.9, 7.7). Of 171 cases, 71% (n = 122) occurred in blacks and 2% (n = 3) occurred in Asian-Pacific islanders. Age 0 to 4 years (107 of 171) compared with age 5 to 14 years (64 of 171) was an additional risk factor for the development of tuberculosis (odds ratio, 3.4; 95% confidence interval 2.5, 4.7)), whereas gender was not. Males accounted for 49% of cases (83 of 171). During the period 1983 to 1993 there was no trend of increasing or decreasing numbers among child cases (trend test P = 0.94) despite significant changes by year. The purified protein derivative test had a 9% (8 of 89) false negative rate and was significantly more likely to be negative in children younger than 1 year (4 of 12 vs. 4 of 77; P = 0.01). During the 2-year interval 1992 to 1993, 19% of cases were thought to be preventable. We believe that the PPD skin test is useful and an improved contact investigation is essential to preventing childhood tuberculosis. Miniepidemics of transmission of tuberculosis from adults to a large group of children partially explain the observed disease pattern.

Identification of a contaminating Mycobacterium tuberculosis strain with a transposition of an IS6110 insertion element resulting in an altered spoligotype.

ABSTRACT Molecular fingerprinting with the IS6110insertion sequence is useful for tracking transmission ofMycobacterium tuberculosis within a population or confirming specimen contamination in the laboratory or through instrumentation. Secondary typing with other molecular methods yields additional information as to the relatedness of strains with similar IS6110 fingerprints. Isolated, relatively rare, random events within the M. tuberculosis genome alter molecular fingerprinting patterns with any of the methods; therefore, strains which are different by two or more typing methods are usually not considered to be closely related. In this report, we describe two strains of M. tuberculosis, obtained from the same bronchoscope 2 days apart, that demonstrated unique molecular fingerprinting patterns by two different typing methods. They were closely linked through the bronchoscope by a traditional epidemiologic investigation. Genetic analysis of the two strains revealed that a single event, the transposition of an IS6110 insertion sequence in one of the strains, accounted for both the differences in the IS6110pattern and the apparent deletion of a spacer in the spoligotype. This finding shows that a single event can change the molecular fingerprint of a strain in two different molecular typing systems, and thus, molecular typing cannot be the only means used to track transmission of this organism through a population. Traditional epidemiologic techniques are a necessary complement to molecular fingerprinting so that radical changes within the fingerprint pattern can be identified.

Bloodstream Infections among HIV-Infected Outpatients, Southeast Asia

Bloodstream infections (BSIs) are a major cause of illness in HIV-infected persons. To evaluate prevalence of and risk factors for BSIs in 2,009 HIV-infected outpatients in Cambodia, Thailand, and Vietnam, we performed a single Myco/F Lytic blood culture. Fifty-eight (2.9%) had a clinically significant BSI (i.e., a blood culture positive for an organism known to be a pathogen). Mycobacterium tuberculosis accounted for 31 (54%) of all BSIs, followed by fungi (13 [22%]) and bacteria (9 [16%]). Of patients for whom data were recorded about antiretroviral therapy, 0 of 119 who had received antiretroviral therapy for ≥14 days had a BSI, compared with 3% of 1,801 patients who had not. In multivariate analysis, factors consistently associated with BSI were fever, low CD4+ T-lymphocyte count, abnormalities on chest radiograph, and signs or symptoms of abdominal illness. For HIV-infected outpatients with these risk factors, clinicians should place their highest priority on diagnosing tuberculosis.

The incremental cost-effectiveness of engaging private practitioners to refer tuberculosis suspects to DOTS services in Jogjakarta, Indonesia.

We aimed to evaluate the incremental cost-effectiveness of engaging private practitioners (PPs) to refer tuberculosis (TB) suspects to public health centers in Jogjakarta, Indonesia. Effectiveness was assessed for TB suspects notified between May 2004 and April 2005. Private practitioners referred 1,064 TB suspects, of which 57.5% failed to reach a health center. The smear-positive rate among patients reaching a health center was 61.8%. Two hundred eighty (280) out of a total of 1,306 (21.4%) new smear-positive cases were enrolled through the PPs strategy. The incremental cost-effectiveness ratio per smear-positive case successfully treated for the PPs strategy was US

Preventable Childhood Tuberculosis in Alabama: Implications and Opportunity

351.66 (95% CI 322.84-601.33). On the basis of an acceptability curve using the National TB control programs willingness-to-pay threshold (US

Voluntary counselling and testing uptake and HIV prevalence among tuberculosis patients in Jogjakarta, Indonesia

448.61), we estimate the probability that the PPs strategy is cost-effective at 66.8%. The strategy of engaging PPs was incrementally cost-effective, although under specific conditions, most importantly a well-functioning public directly observed treatment, short-course (DOTS) program.

Molecular Typing of Mycobacterium tuberculosis Strains with a Common Two-Band IS6110 Pattern

Childhood tuberculosis (TB) cases indicate recent community transmission and thus reflect the effectiveness of TB control efforts, particularly the contact investigation. Objective.u2003To evaluate all preventable childhood TB cases and implications in the context of TB morbidity trends. Design.u2003Statewide morbidity trends are presented from 1983 to 1997. Since 1992, each child TB case is classified as either preventable or not preventable, based on a standard definition. Main Outcome Measures.u2003Case characteristics (preventable and not preventable), TB disease rates over time, and reasons for preventable case classification. Setting.u2003Alabama TB control program, from January 1, 1983 through December 31, 1997. Results.u2003For the period 1983–1997, nonwhite children had a higher disease rate (rate ratio: 5.7; 95% confidence interval: 4.3,7.6) than white children. Since 1990, the overall child rate has increased significantly despite a decline in the adult rate. Among 120 child cases diagnosed from 1992 to 1997, 25 (21%) were classified as preventable. The causes were contact investigation interview failure (12/25 = 48%), delay to evaluation (16%), source case noncompliance with previously prescribed preventive therapy (16%), and source case diagnosed out of state (16%) with no initial investigation performed in Alabama. All preventable cases identified were black children; the proportion of preventable cases did not vary by age group or sex. During 1996, the case rate for nonwhite children exceeded that of adult whites. Conclusions.u2003Childhood TB in Alabama for nonwhites is rising despite a national downward trend. TB is clearly a disproportionate disease burden for the states African American population, and the median case age is falling. Additional research and improved training in contact investigation are required to assess this situation and effectively intervene.

Predictive model to identify positive tuberculosis skin test results during contact investigations

We aimed to establish HIV prevalence and uptake of unlinked anonymous testing and voluntary counselling and testing (VCT) among tuberculosis (TB) patients in Jogjakarta, Indonesia. We introduced unlinked anonymous HIV testing for TB patients attending directly observed treatment, short-course services between April and December 2006. Patients were additionally offered VCT services. Of 1269 TB patients who were offered unlinked anonymous testing, 989 (77.9%; 95% CI 75.6-80.1%) accepted. HIV prevalence was 1.9% (95% CI 1.6-2.2%). HIV infections were less frequently diagnosed among TB patients who attended a public health centre [odds ratio (OR) 0.15; 95% CI 0.03-0.70] rather than public hospital. They were more frequent in TB patients with a university education background (OR 5.16; 95% CI 1.01-26.63) or a history of HIV testing (OR 57.87; 95% CI 9.42-355.62). Of the 989 patients who accepted unlinked anonymous testing, only 133 (13.4%; 95% CI 11.5-15.7%) expressed interest in VCT. Of these, 52 (39.1%; 95% CI 31.2-47.6%) attended VCT, but interest was higher among students and those offered VCT by public health centres. The HIV prevalence in Jogjakarta is higher than expected and needs to be monitored cautiously. Unlinked anonymous HIV testing is well accepted and can be implemented with modest additional efforts.

A Decision Tree for Tuberculosis Contact Investigation

We conducted a population-based molecular typing of all Mycobacterium tuberculosis isolates obtained in Alabama since 1994. Of 2,452 isolates, 1,013 (41%) had fewer than 6 bands of IS6110; 348 (14%) had a single two-band pattern (JH2). With conventional epidemiologic methods, we identified three groups of related patients with JH2 isolates. Spoligotyping and pattern of variable number of tandem repeats identified 10 molecular groups; two found by conventional methods were subdivided.