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Background: Although Hispanic patients have high rates of end-stage liver disease and liver cancer, for which liver transplantation (LT) offers the best long-term outcomes, they are less likely to receive LT. Studies of end-stage renal disease patients and kidney transplant candidates have shown that targeted, culturally relevant interventions can increase the likelihood of Hispanic patients receiving kidney transplant. However, similar interventions remain largely unstudied in potential LT candidates., Methods: Referrals to a single center in Texas with a large Hispanic patient population were compared before (01/2018-12/2019) and after (7/2021-6/2023) the implementation of a targeted outreach program. Patient progress toward LT, reasons for ineligibility, and differences in insurance were examined between the two eras., Results: A greater proportion of Hispanic patients were referred for LT after the implementation of the outreach program (23.2% vs 26.2%, p = 0.004). Comparing the pre-outreach era to the post-outreach era, more Hispanic patients achieved waitlisting status (61 vs 78, respectively) and received a LT (971 vs 82, respectively). However, the proportion of Hispanic patients undergoing LT dropped from 30.2% to 20.3%. In the post-outreach era, half of the Hispanic patients were unable to get LT for financial reasons (112, 50.5%)., Conclusions: A targeted outreach program for Hispanic patients with end-stage liver disease effectively increased the total number of Hispanic LT referrals and recipients. However, many of the patients who were referred were ineligible for LT, most frequently for financial reasons. These results highlight the need for additional research into the most effective ways to ameliorate financial barriers to LT in this high-need community., Competing Interests: Declaration of competing interest None., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Postoperative respiratory failure, defined as ventilator dependency for more than 48 hours or unplanned reintubation within 30 days, is a costly complication of cardiac surgery that increases mortality and length of stay. Stratification of patients by risk upon intensive care unit admission could identify cases requiring early measures to prevent respiratory failure. This study aimed to develop and validate a risk score for postoperative respiratory failure after cardiac surgery., Methods: This retrospective analysis of 4262 patients admitted to the cardiovascular intensive care unit after major cardiac surgery between January 2013 and December 2017, used The Society of Thoracic Surgeons database and ventilator data from the respiratory therapy department. Patients were randomly and equally assigned to development and validation cohorts. Covariates used in the multivariable models were assigned weighted points proportional to their β regression coefficient values to create the risk score, which categorized patients into low, medium, and high risk of postoperative respiratory failure., Results: In both cohorts, postoperative respiratory failure risk was significantly different between risk categories. Compared with low-risk patients, moderate-risk patients had a 2 times greater risk, and high-risk patients had a 4-7 times greater risk. Body mass index, previous cardiac surgery, cardiopulmonary bypass, cardiogenic shock, pulmonary disease presence, baseline functional status, hemodynamic instability, and number of blood products used intraoperatively were significant predictors of respiratory failure., Conclusions: This risk score can stratify patients by risk for developing postoperative respiratory failure after major cardiac surgery, which may help in the development of preventive measures., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Since February 2020, over 2.5 million Texans have been diagnosed with COVID-19, and 20% are young adults at risk for SARS-CoV-2 exposure at work, academic, and social settings. This study investigated demographic and clinical risk factors for severe disease and readmission among young adults 18-29 years old, who were diagnosed at a hospital encounter in Houston, Texas, USA., Methods and Findings: A retrospective registry-based chart review was conducted investigating demographic and clinical risk factors for severe COVID-19 among patients aged 18-29 with positive SARS-CoV-2 tests within a large metropolitan healthcare system in Houston, Texas, USA. In the cohort of 1,853 young adult patients diagnosed with COVID-19 infection at a hospital encounter, including 226 pregnant women, 1,438 (78%) scored 0 on the Charlson Comorbidity Index, and 833 (45%) were obese (≥30 kg/m2). Within 30 days of their diagnostic encounter, 316 (17%) patients were diagnosed with pneumonia, 148 (8%) received other severe disease diagnoses, and 268 (14%) returned to the hospital after being discharged home. In multivariable logistic regression analyses, increasing age (adjusted odds ratio [aOR] 1.1, 95% confidence interval [CI] 1.1-1.2, p<0.001), male gender (aOR 1.8, 95% CI 1.2-2.7, p = 0.002), Hispanic ethnicity (aOR 1.9, 95% CI 1.2-3.1, p = 0.01), obesity (3.1, 95% CI 1.9-5.1, p<0.001), asthma history (aOR 2.3, 95% CI 1.3-4.0, p = 0.003), congestive heart failure (aOR 6.0, 95% CI 1.5-25.1, p = 0.01), cerebrovascular disease (aOR 4.9, 95% CI 1.7-14.7, p = 0.004), and diabetes (aOR 3.4, 95% CI 1.9-6.2, p<0.001) were predictive of severe disease diagnoses within 30 days. Non-Hispanic Black race (aOR 1.6, 95% CI 1.0-2.4, p = 0.04), obesity (aOR 1.7, 95% CI 1.0-2.9, p = 0.046), asthma history (aOR 1.7, 95% CI 1.0-2.7, p = 0.03), myocardial infarction history (aOR 6.2, 95% CI 1.7-23.3, p = 0.01), and household exposure (aOR 1.5, 95% CI 1.1-2.2, p = 0.02) were predictive of 30-day readmission., Conclusions: This investigation demonstrated the significant risk of severe disease and readmission among young adult populations, especially marginalized communities and people with comorbidities, including obesity, asthma, cardiovascular disease, and diabetes. Health authorities must emphasize COVID-19 awareness and prevention in young adults and continue investigating risk factors for severe disease, readmission and long-term sequalae., Competing Interests: The authors have declared that no competing interests exist.

Objective: A disproportionate number of tuberculosis cases and tuberculosis deaths occur among persons experiencing homelessness in the United States. Our objective was to identify risks for homelessness and death during mycobacterial treatment among persons experiencing homelessness with tuberculosis in Texas., Methods: Using data from the Centers for Disease Control and Prevention's TB Genotyping Information Management System, we evaluated data on demographic, laboratory, and clinical characteristics of persons experiencing homelessness in Texas during the year before tuberculosis diagnosis, from January 1, 2010, through December 31, 2017., Results: Of 10 130 new diagnoses of tuberculosis among persons living in Texas during the study period, 543 were reported as being homeless in the year before tuberculosis diagnosis. The odds of dying during treatment were 2.26 (95% confidence interval, 1.68-3.03) times higher among persons with tuberculosis experiencing homelessness than among persons with tuberculosis living in homes., Conclusions: Our findings indicate that persons experiencing homelessness bear an undue burden of tuberculosis mortality in Texas. The burden may be related to poorer health caused by poverty stressors, comorbidities, or lack of access to health care.

Background: Lung transplantation is the gold standard for a carefully selected patient population with end-stage lung disease. This study sought to create a risk stratification model using only preoperative recipient data to predict 1-year postoperative mortality during the pretransplant assessment., Methods: Data of lung transplant recipients at Houston Methodist Hospital in Houston, Texas from January 2009 to December 2014 were extracted from the United Network for Organ Sharing (UNOS) database. Patients were randomly divided into development and validation cohorts. Cox proportional-hazards models were conducted. Variables associated with 1-year mortality after transplantation were assigned weights on the basis of the beta coefficients, and risk scores were derived. Patients were stratified into low-, medium- and high-risk categories. The model was validated using the validation data set and data from other US transplant centers in the UNOS database., Results: The study randomized 633 lung recipients from Houston Methodist Hospital into development (n = 317 patients) and validation cohorts (n = 316). The 1-year survival after transplantation was significantly different among risk groups: 95% (low risk), 84% (medium risk), and 72% (high risk) (P < .001), with a C-statistic of 0.74. Patient survival in the validation cohort was also significantly different among risk groups (85%, 77%, and 65%, respectively; P < .001). Validation of the model with the UNOS data set included 9920 patients and found 1-year survival to be 91%, 86%, and 82%, respectively (P < .001)., Conclusions: Using only recipient data collected at the time of the prelisting evaluation, this simple scoring system was found to have good discrimination power and could be a practical tool in the assessment and selection of potential lung transplant recipients., (Copyright © 2019 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Tuberculosis (TB) and diabetes mellitus (DM) comorbidity (TB-DM) is a major public health challenge worldwide. This analysis aimed to determine the risk factors and trends associated with TB-DM morbidity and mortality., Methods: Risk factors for TB-DM morbidity and mortality were identified by logistic regression using de-identified surveillance data of all TB patients from Texas, USA. reported between 01/2010-12/2016. Non-parametric testing was used for the morbidity and mortality trends., Results: From 2010 to 2016, 1400/9002 (15.6%) TB patients were diabetic with an annual prevalence increase from 12.5% to 18.7% (p = 0.005). Reported TB-DM patients had a higher mortality (10.3%) than non-DM patients (7.6%, p = 0.001) with nearly a 3-fold increase in the odds of death (overall and during treatment). Older age, being Hispanic, chronic kidney failure, pulmonary cavitation and positive TB culture or smear were associated with TB-DM. Age ≥45, US-birth, resident of long-term care facility, injecting-drug user, chronic kidney disease, TB meningitis, abnormal chest radiograph, non-conversion of culture, and HIV(+) were independently associated with a higher mortality., Conclusions: TB-DM is an increasing public health problem in Texas with significantly high mortality. Risk factors for mortality determined by multivariate modeling will provide a foundation for the development of more effective strategies for TB-DM management., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Head and neck tuberculosis (HNTB) especially cervical lymphadenopathy are the most common extrapulmonary indications of TB, but remain a diagnostic challenge. In this study, we describe and analyze the epidemiologic characteristics of HNTB on a population-level., Materials and Methods: We retrospectively assessed 547 HNTB cases reported to the Centers for Disease Control and Prevention's TB Genotyping Information Management System in Texas from 2009 to 2016 and compare and contrast differences between diagnosed exclusively HNTB and HNTB with concurrent pulmonary tuberculosis (PTB)., Results: The majority of patients with HNTB were diagnosed with cervical lymphadenopathy (96.9%), age 25-44 (47.3%) and female (52.7%). Co-infection with human immunodeficiency virus, being homeless, excessive alcohol use within the past 12 months and drug use were more frequently seen for HNTB with concurrent pulmonary involvement compared to reported patients with exclusively HNTB. The highest prevalence of Mycobacterium tuberculosis lineage in exclusively HNTB was Euro-American L4 (52.3%), followed by Indo-Oceanic L1 (21.5%) and East-Asian L2 (13.1%). One multidrug resistant TB case was identified. Seven deaths were reported during treatment., Conclusion: Our findings provide a better understanding of the epidemiology of HNTB and characteristics associated with the disease at the population-level, which is important in managing HNTB patients., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background and Objectives: HIV-infected patients are at risk for developing chronic kidney disease (CKD), defined by estimated glomerular filtration rate (eGFR) <60 ml/min/1.73m2. Our purpose was to understand the genesis of CKD in HIV patients from a large urban clinic in Houston, Texas, USA, and to characterize progression of CKD in the cohort., Design, Setting, Participants and Measurements: A retrospective cohort study (2012-2016) was conducted in all HIV-infected patients seen in a federally qualified community health center in Houston, Texas. CKD prevalence and its association with HIV viral load and CD4 count were determined. The association of the change in eGFR over time and comorbidities was assessed using linear mixed models., Results: Of 3714 HIV-infected patients analyzed, 153 (4.1%) had CKD. The prevalence of CKD in the different racial groups was 5.4% White, 4.0% African American, 2.8% Hispanic/Latino and 3.2% Asian. There was no difference in the rate of decline in kidney function in White vs. African American HIV infected patients with CKD. Compared with non-CKD patients, CKD patients were older, had lived longer with HIV infection, had lower CD4 cell counts, higher proportions of hypertension, hyperlipidemia, and cerebrovascular disease, and had significantly higher rates of eGFR deterioration represented by a median decrease of 26.5% from first to last follow-up eGFR (versus 0% change). Linear mixed modeling identified older age, male gender, White race, longer time with HIV infection, hypertension, history of kidney stones, cerebrovascular disease, autoimmune disease, increased potassium and total cholesterol levels, and being treated with combination ART as associated with a worsening eGFR over time., Conclusion: This study demonstrates a prevalence of CKD in HIV-infected patients of 4.1% and points to an important role for HIV medications and other common comorbidities in the genesis and progression of kidney disease. Importantly, CKD was not more prevalent in African Americans than in Whites, perhaps due to a low prevalence of IV drug abuse as inferred from the lower prevalence of HCV infection in this cohort., Competing Interests: We thank the Community Scholars Program Office of Graduate Medical Education at Houston Methodist Research Institute funded by Occidental Petroleum (Oxy Oil) Company for supporting the writing manuscript. There are no patents, products in development or marketed products to declare. This does not alter our adherence to all the PLOS ONE policies on sharing data and materials, as detailed online in the guide for authors.

Background: As the most severe form of tuberculosis (TB), TB meningitis (TBM) is still associated with high mortality even in developed countries. In certain areas of the United States (U.S.), more than 50% of the TBM patients die with TB or have neurological sequelae and complications despite the availability of advanced health care. This population-based analysis aimed to determine the risk factors and trends associated with TBM morbidity and mortality using state-wide surveillance data., Methods: De-identified surveillance data of all confirmed TB patients from the state of Texas between 01/2010 and 12/2017 reported to the National TB Surveillance System was analyzed. Spatial distribution of TBM cases was presented by Stata's Geographic Information Systems mapping. Univariate and multiple generalized linear modeling were used to identify risk factors associated with meningitis morbidity and mortality. Non-parametric testing was used to analyze morbidity and mortality trends., Results: Among 10,103 TB patients reported in Texas between 2010 and 2017, 192 (1.9%) had TBM. During this 8-year period, the TBM proportion fluctuated between 1.5% and 2.7% with peaks in 2011 (2.7%) and 2016 (2.1%) and an overall non-significant trend (z = -1.32, p = 0.19). TBM had a higher mortality at diagnosis (8.9%), during treatment (14.1%) and overall (22.9%) compared to non-TBM (1.9%, 5.3%, and 7.2%, respectively, p<0.001). While mortality during treatment was unchanged over time in non-TBM patients (z = 0.5, p = 0.62), it consistently increased in TBM patients after 2013 (z = 3.09, p = 0.002). TBM patients had nearly five times the risk for overall death in multivariate analysis [aRR 4.91 (95% CI 3.71, 6.51), p<0.001]. TBM patients were younger, and more likely to present with miliary TB or HIV (+). Age ≥45 years, resident of a long-term care facility, IDU, diabetes, chronic kidney disease, abnormal chest radiography, positive AFB smear or culture and HIV (+) were independently associated with higher mortality., Conclusion: TBM remains challenging in Texas with significantly high mortality. Risk factors determined by multivariate modeling will inform health professionals and lay a foundation for the development of more effective strategies for TBM prevention and management., Competing Interests: The authors have declared that no competing interests exist.

Background: Making an accurate prognosis for mortality during tuberculosis (TB) treatment in TB-diabetes (TB-DM) comorbid patients remains a challenge for health professionals, especially in low TB prevalent populations, due to the lack of a standardized prognostic model., Methods: Using de-identified data from TB-DM patients from Texas, who received TB treatment had a treatment outcome of completed treatment or died before completion, reported to the National TB Surveillance System from January 2010-December 2016, we developed and internally validated a mortality scoring system, based on the regression coefficients., Results: Of 1227 included TB-DM patients, 112 (9.1%) died during treatment. The score used nine characteristics routinely collected by most TB programs. Patients were divided into three groups based on their score: low-risk (< 12 points), medium-risk (12-21 points) and high-risk (≥22 points). The model had good performance (with an area under the receiver operating characteristic (ROC) curve of 0.83 in development and 0.82 in validation), and good calibration. A practical mobile calculator app was also created ( https://oaa.app.link/Isqia5rN6K )., Conclusion: Using demographic and clinical characteristics which are available from most TB programs at the patient's initial visits, our simple scoring system had good performance and may be a practical clinical tool for TB health professionals in identifying TB-DM comorbid patients with a high mortality risk.

Objective: To develop and validate a simple prognostic scoring system to predict the mortality risk during treatment in tuberculosis patients., Methods: Using data from the CDC's Tuberculosis Genotyping Information Management System of TB patients in Texas reported from 01/2010 to 12/2016, age ≥ 15 years and having an outcome as "completed" or "died", we developed and validated a prognostic mortality scoring system-based logistic regression beta-coefficients., Results: The developmental and validation cohorts consisted of 3378 and 3377 patients, respectively. The score used 9 demographic and clinical characteristics, which are usually available at the patient's initial visits to a healthcare facility. Prognostic scores were categorized into three groups that predicted mortality: low-risk (<15 points), medium-risk (15-18 points), and high-risk (>18 points). The model had excellent discrimination and calibration with an area under the receiver operating characteristic curve of 0.82 and 0.80, and a non-significant Hosmer-Lemeshow test P = 0.514 and P = 0.613 in the developmental and validation cohorts, respectively., Conclusion: Our validated TB prognostic scoring system, which used demographic and clinical characteristics available at the patient's initial visits, can be a practical tool for health care providers to identify TB patients with high mortality risk so that appropriate treatment, medical supports and follow-up resources could be appropriately allocated., (Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Interferon-γ release assays (IGRAs) are the preferred diagnostic test for tuberculosis (TB) infection in at-risk populations in developed countries. However, IGRAs have high false-negative rates in patients with TB disease. Population-based studies assessing the factors associated with negative IGRA results in TB patients have not been performed. Using statewide TB surveillance data of culture-confirmed TB patients in Texas, USA, during 2013-2015, we describe the patient characteristics and treatment outcomes associated with false-negative IGRA results. Among 2,854 TB patients, 1,527 (53.5%) had an IGRA result; 97.4% (1,487/1,527) of those had a positive (87.7%) or negative (12.3%) result. Older age, HIV co-infection, non-Hispanic white race/ethnicity, and being tested with T-SPOT.TB were associated with negative IGRA results. TB patients with negative IGRA results had a higher mortality, potentially due to delayed treatment. Healthcare providers should consider these risk factors when making decisions for patients with suspected TB and negative IGRA results and potentially provide treatment.

Background: Tracking the dissemination of specific Mycobacterium tuberculosis (Mtb) strains using genotyped Mtb isolates from tuberculosis patients is a routine public health practice in the United States. The present study proposes a standardized cluster investigation method to identify epidemiologic-linked patients in Mtb genotype clusters. The study also attempts to determine the proportion of epidemiologic-linked patients the proposed method would identify beyond the outcome of the conventional contact investigation., Methods: The study population included Mtb culture positive patients from Georgia, Maryland, Massachusetts and Houston, Texas. Mtb isolates were genotyped by CDC's National TB Genotyping Service (NTGS) from January 2006 to October 2010. Mtb cluster investigations (CLIs) were conducted for patients whose isolates matched exactly by spoligotyping and 12-locus MIRU-VNTR. CLIs were carried out in four sequential steps: (1) Public Health Worker (PHW) Interview, (2) Contact Investigation (CI) Evaluation, (3) Public Health Records Review, and (4) CLI TB Patient Interviews. Comparison between patients whose links were identified through the study's CLI interviews (Step 4) and patients whose links were identified earlier in CLI (Steps 1-3) was conducted using logistic regression., Results: Forty-four clusters were randomly selected from the four study sites (401 patients in total). Epidemiologic links were identified for 189/401 (47 %) study patients in a total of 201 linked patient-pairs. The numbers of linked patients identified in each CLI steps were: Step 1 - 105/401 (26.2 %), Step 2 - 15/388 (3.9 %), Step 3 - 41/281 (14.6 %), and Step 4 - 28/119 (30 %). Among the 189 linked patients, 28 (14.8 %) were not identified in previous CI. No epidemiologic links were identified in 13/44 (30 %) clusters., Conclusions: We validated a standardized and practical method to systematically identify epidemiologic links among patients in Mtb genotype clusters, which can be integrated into the TB control and prevention programs in public health settings. The CLI interview identified additional epidemiologic links that were not identified in previous CI. One-third of the clusters showed no epidemiologic links despite being extensively investigated, suggesting that some improvement in the interviewing methods is still needed.

The isolation of Mycobacterium tuberculosis from blood culture specimens has been associated with human immunodeficiency virus (HIV) co-infection with variable impact on tuberculosis (TB) mortality reported. The overwhelming majority of M. tuberculosis bacteraemia cases were described in developing countries. We present a nested case-control analysis of clinical, sociodemographic and behavioural risk factors in patients with positive M. tuberculosis blood cultures compared with patients with negative blood cultures from a 9-year population-based active TB surveillance study conducted in Houston, Texas. There were 42 patients with M. tuberculosis bacteraemia, 47 blood culture negative patients and 3573 patients for whom no mycobacterial blood culture was requested. HIV infection was more common in patients for whom a mycobacterial blood culture was requested (79.8% versus 15.1% p <0.001). Of the patients with M. tuberculosis bacteraemia, six were HIV negative or had no documentation of HIV status, including five with immunosuppressive conditions other than HIV. Patients with M. tuberculosis bacteraemia were more likely than patients with negative blood cultures to be deceased at diagnosis or to die while on TB therapy (50.0% versus 17.0%, p <0.01), to report men-who-have-sex-with-men behaviour (31.7% versus 13.0%, p 0.03), to have renal failure (28.6% versus 6.4%, p 0.01), and to have HIV RNA levels higher than 500 000 copies/mL (61.9% versus 17.2%, p ≤0.01). Requests for mycobacterial culture of blood specimens were more common in HIV-infected individuals, and the presence of M. tuberculosis bacteraemia was associated with a significant increase in mortality., (© 2013 The Authors Clinical Microbiology and Infection © 2013 European Society of Clinical Microbiology and Infectious Diseases.)

Tuberculosis genotypic clustering is used as a proxy for recent transmission. The association between clustering and recent transmission becomes problematic when the genotyping method lacks specificity in defining a cluster, as well as for clusters with extensive jurisdictional histories and/or common genotypes. We investigated the four largest spoligotype/12 loci MIRU-VNTR-defined clusters in Harris County, Texas from 2006-2012 to determine their historical contribution to tuberculosis morbidity, estimate the contributions from recent and remote transmission, and determine the impact of secondary genotyping on cluster definition. The clusters contained 189, 64, 51 and 38 cases. Each cluster was linked to cluster(s) previously identified by Houston Tuberculosis Initiative; 3 since 1995 and the fourth in 2002. Among cases for which timing of Mycobacterium tuberculosis transmission relative to tuberculosis disease could be ascertained, nearly equal proportions were associated with recent and remote transmission. The extent to which genotyping with an additional 12 MIRU-VNTR loci modified the cluster definition varied from little or no impact for the two smaller clusters to moderate impact for the larger clusters. Tuberculosis control measures to reduce morbidity associated with large clusters must involve strategies to identify and treat individuals who recently acquired infection, as well as persons infected for years., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Tuberculosis (TB) surveillance among the homeless is not supported by the political will necessary for TB elimination. We merged the first stakeholder-accepted enumeration of homeless persons with existing surveillance data to assess TB risk among the homeless in Houston, Texas. The average incidence per 100,000 was 411 among homeless and 9.5 among housed persons. The homeless were more likely than the housed to be US-born, clustered, and in a larger-sized cluster. Multivariate analysis revealed that TB rates among the homeless were driven not by comorbidities but by social determinants. Homeless patients were hospitalized more days than the housed and required more follow-up time. Reporting of TB rates for populations with known health disparities could help reframe TB prevention and better target limited funds.

Background: The epidemiology of pediatric tuberculosis (TB) from 1995 to 2000 in Harris County, TX, has been previously reported. This study was conducted to evaluate the continued trends of Mycobacterium tuberculosis clustering and the role of genotyping in pediatric TB., Methods: Data came from the Houston Tuberculosis Initiative, a prospective population-based active surveillance and molecular epidemiology project. The study population consisted of TB patients ≤18 years of age diagnosed in Harris County, TX, from 2000 to 2004. Available Mycobacterium tuberculosis isolates were characterized by insertion sequence 6110 restriction fragment length polymorphism and spoligotyping., Results: One hundred three pediatric TB cases were enrolled in the Houston Tuberculosis Initiative study from 2000 to 2004. Sixty-one (59%) patients had potential source cases. Mycobacterium tuberculosis isolates were available and genotyped for 36 pediatric cases; 27 (75%) were clustered into 22 different genotypes. Of the 20 genotyped patients with a potential source case, 16 (80%) were clustered. Genotypes matched the potential source case in 12 cases. Eleven of the 16 (69%) genotyped patients without a potential source case were clustered., Conclusions: Compared with pediatric cases between 1995 and 2000, there was a significant increase in the number of patients with unknown potential source cases that were clustered within the Houston Tuberculosis Initiative database. Because genotypic clustering is associated with recent transmission, there appears to be a failure in the identification of potential source cases through contact tracing. Reduced funding of public health departments forces more limited TB control activities and therefore could pose a threat to TB control.

To reach the tuberculosis (TB) elimination goals established by the Institute of Medicine (IOM) and the Centers for Disease Control and Prevention (CDC), measures must be taken to speed the currently stagnant TB elimination rate and curtail a future peak in TB incidence. Increases in TB incidence have historically coincided with immigration, poverty, and joblessness; all situations that are currently occurring worldwide. Effective TB elimination strategies will require the geographical elucidation of areas within the U.S. that have endemic TB, and systematic surveillance of the locations and location-based risk factors associated with TB transmission. Surveillance data was used to assess the spatial distribution of cases, the yearly TB incidence by census tract, and the statistical significance of case clustering. The analysis revealed that there are neighborhoods within Houston/Harris County that had a heavy TB burden. The maximum yearly incidence varied from 245/100,000-754/100,000 and was not exclusively dependent of the number of cases reported. Geographically weighted regression identified risk factors associated with the spatial distribution of cases such as: poverty, age, Black race, and foreign birth. Public transportation was also associated with the spatial distribution of cases and census tracts identified as high incidence were found to be irregularly clustered within communities of varied SES., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Previous geospatial analysis of the well-defined Houston Tuberculosis Initiative (HTI) database identified an association between the use of city-bus transportation (inclusive of time onboard) and Tuberculosis (TB) incidence in Houston/Harris County census tracts (paper submitted). This paper is an extension of those findings. Contact investigations on school buses have reported a high rate of positive tuberculin skin tests in the persons traveling with the index case and have shown an association with bus ride duration. In Houston, city bus routes are veins connecting even the most diverse of populations within the metropolitan area. Among HTI participants, TB patients who reported weekly bus use were more likely to have demographic and social risk factors associated with poverty, immune suppression and health disparities. An equal proportion of bus riders and non-bus riders were cultured for Mycobacterium tuberculosis (MTB), yet 75% of bus riders were clustered with a mean cluster size of 50.14, indicating recent transmission, compared to 56% of non-bus riders (OR = 2.4, p < 0.001) with a mean cluster size of 28.9 (p < 0.01). Individual bus routes, including one route servicing the local hospitals, were found to be risk factors for endemic MTB clustered strains and the routes themselves geographically connect the census tracts previously identified as having endemic TB., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: Intracranial tuberculomas are rare manifestations of tuberculosis (TB). An extensive literature review revealed that no study of consecutive adults with intracranial tuberculoma has been conducted in the USA., Methods: This retrospective study consisted of 12 adults consecutively identified with intracranial tuberculomas from 1995 to 2009 in Houston, Texas. Of the 12 cases, 8 had a histopathological diagnosis, while 4 had a probable diagnosis based on the following criteria: (1) Mycobacterium tuberculosis identified from a source outside the brain, (2) radiographic confirmation of an intracranial mass, (3) received chemotherapy with 2 or more anti-tuberculosis medications, and (4) clinical response at 1-y follow-up., Results: Common clinical manifestations were altered mental status, fever, and night sweats. Four patients (25%) had a human immunodeficiency virus (HIV) infection. Nine patients (75%) had concomitant M. tuberculosis at at least 1 extracranial site, including 5 patients with pulmonary TB. The median duration of therapy was 11 months. Patients had a 1-y mortality rate of 16.7% and an overall morbidity rate of 20%., Conclusions: Intracranial tuberculomas in Houston, Texas, are rare. Hospital discharge predicted survival at 1 y, despite severe clinical presentations and invasive diagnostic procedures. However, tuberculoma cases are associated with higher mortality rates than non-central nervous system TB cases.

Neurocysticercosis, one of the most common parasitic infections of the human nervous system, has emerged as an important infection in the United States. Neurocysticercosis causes significant morbidity associated with acute seizures, chronic epilepsy, and hydrocephalus.We retrospectively identified patients with definitive or probable neurocysticercosis seen at Ben Taub General Hospital, the largest public teaching hospital in Houston, Texas, from September 1997 through December 2005. We collected demographic, clinical, therapeutic, and outcome variables. Neurocysticercosis was classified according to the location of cysts in imaging studies. We compared cases with parenchymal and extraparenchymal disease.We included 111 patients (48 had definitive and 63 probable neurocysticercosis). The mean age was 28.6 years (standard deviation, 13.6 yr), and the male to female ratio was 2:1. Most patients (93%) were Hispanic immigrants. Sixty (54%) patients had parenchymal disease, 22 (20%) intraventricular, 13 (12%) subarachnoid disease, and 13 (12%) had calcifications only. Additionally, 2 patients had hydrocephalus only, and 1 had ocular cysticercosis. Thirteen (40%) of 32 patients with parenchymal disease and 3 (30%) of 10 patients with calcifications had relapsed seizures at follow-up. Extraparenchymal disease was associated with longer duration of hospitalization compared with parenchymal disease. No deaths were identified in our series during a median follow-up of 1 year.Neurocysticercosis has emerged as an important parasitic infection in developed countries as a result of increased migration. With current management, mortality is limited, but there continues to be significant morbidity. Further studies of the epidemiology and pathophysiology of the infection are urgently needed to develop better preventive and therapeutic strategies.

Interferon-gamma release assays (IGRAs) need be evaluated for effectiveness as screening tests for tuberculosis (TB) infection in drug users. These tests have demonstrated improved sensitivity and specificity, but have not been studied in drug users. These one step blood tests are intended to replace the tuberculin skin test (TST), which is difficult to use and requires 48 hour follow-up, so they are expected to be particularly suitable for risk groups, like drug users, in whom follow-up is problematic. Drug users have traditionally been identified as being at increased risk for acquiring TB disease. The results of our pilot study using the TST and simpler and more sensitive interferon-gamma release assays showed that about 45% of current drug users in Houston tested have at least one test positive for latent tuberculosis infection (LTBI). These preliminary data suggest that there is an important reservoir of LTBI in drug using populations, and the risk of progression to active TB disease with other infections is great. However, LTBI in drug using populations has not been studied in depth and deserves further investigation. We need to evaluate the validity of IGRAs for detection of latent TB infection, the factors associated with LTBI, the incidence and risk for developing active TB disease in drug users and the effectiveness of early treatment of LTBI. We believe that using better tuberculosis screening tools will allow us to more accurately measure the prevalence of latent TB infection and incidence of active TB disease in drug using populations and develop more effective TB prevention and treatment interventions in the community.

Tuberculosis (TB) rates in the United States are disproportionately high for certain ethnic minorities. Using univariate and multivariate analyses, we compared data for 1,318 US-born blacks with 565 US-born non-Hispanic whites who participated in the Houston TB Initiative (1995-2004). All available Mycobacterium tuberculosis isolates underwent susceptibility and genotype testing (insertion sequence 6110 restriction fragment length polymorphism, spoligotyping, and genetic grouping). TB in blacks was associated with younger age, inner city residence, HIV seropositivity, and drug resistance. TB cases clustered in 82% and 77% of blacks and whites, respectively (p = 0.46). Three clusters had >100 patients each, including 1 cluster with a predominance of blacks. Size of TB clusters was unexpectedly large, underscoring the ongoing transmission of TB in Houston, particularly among blacks.

Screening for latent tuberculosis infection (LTBI) with the Mantoux tuberculin skin test (TST) has many limitations including false-positive results due to Mycobacterium bovis bacillus Calmette-Guérin (BCG) vaccination. Three hundred ninety adult inmates with normal screening chest radiographs in a county jail were evaluated for LTBI using TST and an ESAT-6/CFP-10 peptide-based enzyme-linked immunospot assay (T-SPOT.TB). LTBI prevalence rates were 19.0% and 8.5% by T-SPOT.TB and TST, respectively. Overall agreement between test results was 82.8% (kappa = 0.29). Positive T-SPOT.TB results were significantly associated with increased age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01 to 1.06) and intravenous drug use history (OR, 2.92; 95% CI, 1.36 to 6.27). Positive TST results were significantly associated with increased age (OR, 1.06; 95% CI, 1.02 to 1.09) and foreign birth (OR, 6.61; 95% CI, 1.98 to 22.01). Discordant covariates between the assay results included increased age (OR, 0.96; 95% CI, 0.94 to 0.99) and intravenous drug use history (OR, 0.41; 95% CI, 0.19 to 0.88). T-SPOT.TB reactivity is unaffected by prior BCG vaccination. T-SPOT.TB may be more sensitive than TST in diagnosing LTBI among a moderate risk population of inmates, particularly those with intravenous drug use history. Longitudinal studies are needed to assess the positive predictive value of T-SPOT.TB in identifying those most likely to convert to active disease in general populations as well as in high-risk subpopulations.

Background: Because of the obesity epidemic, surgeons are operating on morbidly obese patients in increasing numbers. The aim of this study was to evaluate the impact of morbid obesity on the outcome of laparoscopic splenectomy., Methods: The study group consisted of 120 consecutive patients who underwent laparoscopic splenectomy for benign and malignant disease from March 1996 to May 2005. These patients were retrospectively divided into three groups. Group 1 had a body mass index (BMI) < 30. Group 2 patients had a BMI > or = 30 and < 40 and were considered obese. Group 3 had a BMI > or = 40 and were considered morbidly obese. Data including surgical approach (laparoscopic vs. hand-assisted), operative time, conversion rate, estimated blood loss, splenic weight, length of stay, time to tolerate a diet, pathologic diagnosis, complications, and mortality were recorded., Results: Complete data were available for evaluation of 112 patients of whom 73 (65%) had a BMI < 30, 32 (29%) had a BMI > or = 30 and < 40, and 7 (6%) had a BMI > or = 40. The most frequent indication for splenectomy in all three groups was idiopathic thrombocytopenic purpura (ITP). The operative times were significantly higher in patients with a BMI > 40. Conversion rates were also higher in this group, although this did not reach statistical significance. Patients with a BMI > 30 experienced similar complication rates when compared with patients with a BMI < 30. Only when patients had a BMI > 40 did they experience more complications., Conclusions: Laparoscopic splenectomy was performed safely in obese patients (BMI > 30) with similar results to those of nonobese patients. Only in morbidly obese patients (BMI > 40) do outcomes and complications appear to be affected. Obesity should not be a contraindication to laparoscopic splenectomy.

A single nucleotide polymorphism (SNP), +874T/A, in the first intron of the interferon-gamma (IFN-gamma) gene, has presented associations with human susceptibility to tuberculosis (TB) in some ethnic populations, but not in others. In this population-based case-control study with adult TB patients from Houston, Texas, we found no significant differences of + 874T/A genotypic frequencies between cases and ethnically-matched controls or between advanced forms of TB disease (extra-pulmonary involvement or presence of cavitary disease) and pulmonary TB. Given possible sample size limitations, our results suggest that the IFN-gamma +874T/A mutation has no association with TB susceptibility or TB disease severity.

Objectives: To analyse the traditional and molecular epidemiology of drug-resistant tuberculosis (DRTB) in Houston and Harris County, Texas in the setting of decreasing disease incidence., Methods: Case-control study of 193 patients with DRTB and 1977 patients with drug-susceptible TB (DSTB) identified from a population-based surveillance, 1995-2001., Results: In a multivariate logistic regression, the following risk factors were found to be predictors of having DRTB (P< or =0.05): human immunodeficiency virus (HIV) seropositivity, Hispanic ethnicity, Asian ethnicity, history of past TB; whereas being foreign born, having a history of past TB, and younger age were predictors of MDRTB. There were 15 patients who acquired drug resistance while on therapy, and they were significantly more likely than controls to be HIV-seropositive, be of Asian ethnicity, have smear-positive pulmonary disease and present with pleural effusion on chest radiograph. No difference in 6-month mortality between DRTB and DSTB cases was found. During the study period, the incidence of DRTB remained constant., Conclusions: In Houston, there is a steady, low-level, incidence of DRTB which disproportionately affects specific subpopulations, with no evidence of increased mortality at 6 months.

Introduction: Laparoscopic colon resection (LCR) is a safe and effective treatment of benign and malignant colonic lesions. There is little question that a steep learning curve exists for surgeons to become skilled and proficient at LCR. Because of this steep learning curve, debate exists regarding the appropriate hospital setting for LCR. We hypothesize that outcomes of LCR performed early in the learning curve at a regional medical center (New Hanover Regional Medical Center; NHRMC) and a university medical center (Baylor College of Medicine; BCM) would not be significantly different., Methods: The first 50 consecutive LCRs performed at each institution between August 2001 and December 2003 were reviewed. Age, mean body mass index (BMI), gender, history of previous abdominal surgery (PAS), operative approach [laparoscopic (LAP) versus hand/laparoscopic assisted (HAL)], conversions (Conv), operative time (OR time), pathology (benign vs. malignant), lymph nodes (LN) harvested in malignant cases, length of stay (LOS), morbidity and mortality were obtained. Continuous data were expressed as mean +/- SD. Data were analyzed by chi, Fisher exact test, or t test., Results: NHRMC patients were on average older females with a higher incidence of PAS. A LAP approach was more frequently performed at BCM (86%), whereas HAL was used more frequently at NHRMC (24%). Conversions to open were similar at both institutions (12%). Benign disease accounted for the majority of operations at both institutions. In cases of malignancy, more LN were harvested at BCM. OR time and LOS were shorter at NHRMC. Complication rates were similar between institutions. There were no anastomotic leaks or deaths., Conclusions: LCR can be performed safely and with acceptable outcomes early in the learning curve at regional medical centers and university medical centers. Outcomes depend more on surgeons possessing advanced laparoscopic skills and adhering to accepted oncologic surgical principles in cases of malignancy, than on the size or location of the healthcare institution.

Screening for latent tuberculosis infection (LTBI) with Mantoux tuberculin skin test (TST) has many limitations, including false-positive results due to exposure to Mycobacterium other than tuberculosis (TB) and BCG vaccination. A total of 474 adult inmates in a county jail were screened for LTBI using TST and a new ESAT-6/CFP-10 peptide-based whole-blood gamma interferon (IFN-gamma) assay. LTBI prevalence was 9.0 and 5.4% as determined by TST and IFN-gamma assay, respectively. Overall, agreement between test results was 90% (kappa = 0.25). Positive TST results were significantly associated with increased age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01 to 1.08), African-American ethnicity (OR, 4.97; 95% CI, 1.58 to 15.68), foreign birth (OR, 20.20; 95% CI, 4.21 to 97.02) and prior incarceration (OR, 6.19; 95% CI, 1.48 to 25.95). Positive IFN-gamma assay results were significantly associated with African-American ethnicity (OR, 5.58; 95% CI, 1.16 to 26.74). Factors associated with statistically significant discordance between TST and IFN-gamma assay results were African-American ethnicity (OR, 0.29; 95% CI, 0.11 to 0.77), foreign birth (OR, 0.23; 95% CI, 0.07-0.80), and prior incarceration (OR, 0.06; 95% CI, 0.01-0.50). Among subjects born in the United States, African-American ethnicity was the only variable significantly associated with positive test results for both TST (OR, 4.26; 95% CI, 1.38 to 13.16) and IFN-gamma assay (OR, 5.74; 95% CI, 1.19 to 27.75) and remained associated with statistically significant discordance between TST and IFN-gamma assay results. The reactivity of the new IFN-gamma assay is unaffected by prior BCG vaccination or serial TSTs but may be diminished in African-Americans. Future longitudinal studies are needed to assess the sensitivity and specificity of this new assay in detecting LTBI.

Objective: To investigate the transmission dynamics of pediatric tuberculosis (TB) by analyzing the clinical characteristics with the molecular profiles of Mycobacterium tuberculosis isolates during a 5-year period., Methods: A retrospective review of a prospective population-based active surveillance and molecular epidemiology project was conducted in private and public pediatric clinics within Houston and Harris County, Texas. The study population consisted of patients who had pediatric TB diagnosed from October 1, 1995, through September 30, 2000. Cases and potential source cases (PSC) were interviewed using a standardized questionnaire. Available Mycobacterium tuberculosis isolates from cases and PSCs were characterized and compared by IS6110 restriction fragment length polymorphism, spoligotyping, and genetic group assignment. Clinical characteristics were described, and molecular characterizations were compared. Data were analyzed by using EpiInfo 6.02b and SAS 8.2., Results: A total of 220 (92%) of 238 pediatric TB cases were included. Epidemiologic and clinical findings were consistent with previous studies. Molecular profiles from 3 cases did not match the profile of PSC. Four previously unknown PSCs were identified using molecular techniques. Fifty-one (71.8%) of 71 isolates matched at least 1 other Houston Tuberculosis Initiative TB database isolate and were grouped into 33 molecular clusters. Cases were more likely to be clustered when the patients were younger than 5 years, identified a source case, or were US born., Conclusions: Traditional contact tracing may not always be accurate, and molecular characterization can lead to identification of previously unrecognized source cases. Recent transmission plays a significant role in the transmission of TB to children as evident by the high degree of clustering found in our study population.

We identified 114 patients with neurocysticercosis admitted to Ben Taub General Hospital in Houston, Texas between January 1994 and June 1997. Most of these patients were born in Mexico (78%) or Central America (16%), but 6% were born in the United States. Review of neurology clinic records identified 54 patients diagnosed with neurocysticercosis, representing 2% of all neurology clinic patients and 16% of all Hispanics diagnosed with seizures. Forty-one patients were interviewed and all reported significant risk factors for infection, including ingestion of undercooked pork, pig husbandry, immigration from and frequent travel to villages in disease-endemic areas, or personal/family history of taeniasis. Among Mexican immigrants, most were born in rural areas in Central (31%) or north central Mexico (38%). Significantly fewer of the patients were from the border states (15%). The median period from immigration to diagnosis was 58 months, but it was 28 months for the 13 patients who had not left the United States after immigration. Although neurocysticercosis is being diagnosed with increasing frequency in the United States, acquisition of infection is still strongly associated with pig husbandry in rural Latin America, with little evidence of local transmission. Even among urban immigrants to the United States and United States-born cases, there is close ongoing contact with disease-endemic villages.

Relatively little is known about the human genetics of susceptibility to common diseases caused by bacterial pathogens. Tuberculosis, caused by Mycobacterium tuberculosis, is a major cause of morbidity and mortality worldwide. So far, genetic studies of tuberculosis susceptibility have largely been focused on adult patients despite the fact that tuberculosis is highly prevalent among children. To study the host genetic component of pediatric tuberculosis susceptibility, we enrolled 184 ethnically diverse families from the Greater Houston area with at least one child affected by pediatric tuberculosis disease. Using a family-based control design, we found allelic variants of the natural resistance-associated macrophage protein gene 1 (NRAMP1) (alias SLC11A1) significantly associated with tuberculosis disease in this pediatric patient population [P = 0.01; odds ratio = 1.75 (95% confidence interval, 1.10-2.77)]. The association of NRAMP1 with pediatric tuberculosis disease was significantly heterogeneous (P = 0.01) between simplex [P <0.0008; odds ratio = 3.13 (1.54-6.25)] and multiplex families (P = 1), suggesting an interplay between mechanisms of genetic control and exposure intensities. In striking contrast to previous studies in the adult population, we observed that the common alleles of NRAMP1 polymorphisms were risk factors for pediatric tuberculosis disease. To explain the different direction of allelic association between adult and pediatric disease, we hypothesize that NRAMP1 influences the speed of progression from infection to tuberculosis disease.

Study Objectives: To investigate the relationship between the number of negative acid-fast bacilli (AFB) smear results and infectivity of pulmonary tuberculosis (TB)., Design: Retrospective analysis., Methods and Subjects: We examined 122 index cases in Harris County, TX, reported in 1998 and 1999. All cases had only negative AFB smear results during the infectious period and were categorized in two groups: group A consisted of cases with only one or two sputum specimens collected and processed, and group B consisted of cases with at least three sputum specimens or at least one bronchoscopic specimen. Tuberculin skin test (TST) results of contacts were ascertained from the results of contact investigations performed by the City of Houston Department of Health and Human Services, Tuberculosis Control Division. Univariate and multivariate analyses were done to explore index case and contact attributes associated with tuberculosis (TB) transmission using positive TST results of contacts as a measure of recent transmission., Results: We found male gender and younger age of index cases along with Hispanic ethnicity of contacts to be independently associated with positive TST results, while younger contacts were less likely to be TST positive. Smear category of the index case (group A vs group B) was not independently associated with transmission. We also found that the first two sputum specimens in cases where three or more were performed yielded 90% of all positive culture results for Mycobacterium tuberculosis (MTB)., Conclusions: We conclude that two sputum specimens negative for AFB stain are adequate for both assessing infectivity and for isolating MTB from patients with pulmonary TB.

Background: There is little systematic information regarding the immune reconstitution inflammatory syndrome (IRIS)., Objective: To determine the incidence, risk factors, and long-term outcome of IRIS in HIV-infected patients receiving highly active antiretroviral therapy (HAART) who were coinfected with one of three common opportunistic pathogens., Design: A retrospective cohort identified through a city-wide prospective surveillance program., Methods: A retrospective chart review was performed for 180 HIV-infected patients who received HAART and were coinfected with Mycobacterium tuberculosis, Mycobacterium avium complex, or Cryptococcus neoformans between 1997 and 2000. Medical records were reviewed for baseline demographics, receipt and type of HAART, response to antiretroviral therapy, development of IRIS, and long-term outcome., Results: In this cohort, 31.7% of patients who received HAART developed IRIS. Patients with IRIS were more likely to have initiated HAART nearer to the time of diagnosis of their opportunistic infection (P < 0.001), to have been antiretroviral naive at time of diagnosis of their opportunistic infection (P < 0.001), and to have a more rapid initial fall in HIV-1 RNA level in response to HAART (P < 0.001)., Conclusions: IRIS is common among HIV-infected persons coinfected with M. tuberculosis, M. avium complex, or C. neoformans. Antiretroviral drug-naive patients who start HAART in close proximity to the diagnosis of an opportunistic infection and have a rapid decline in HIV-1 RNA level should be monitored for development of this disorder.

Objective: Mycobacterium simiae is found primarily in the southwestern United States, Israel, and Cuba, with tap water as its suspected reservoir. Our institution saw an increase in M. simiae isolates in 2001. An investigation into possible contaminated water sources was undertaken., Design: Environmental cultures were performed from water taps in the microbiology laboratory, patient rooms, points in the flow of water to the hospital, and patients' homes. Patient and environmental M. simiae were compared by PFGE., Setting: Military treatment facility in San Antonio, Texas., Patients: All patients with cultures positive for M. simiae between January 2001 and April 2002. Medical records were reviewed., Results: M. simiae was recovered from water samples from the hospital, patients' home showers, and a well supplying the hospital. A single PFGE clone was predominant among water isolates (9 of 10) and available patient isolates (14 of 19). There was an association between exposure to hospital water and pulmonary samples positive for the clonal M. simiae strain (P = .0018). Only 3 of 22 culture-positive patients met criteria for M. simiae pulmonary disease. Of them, two had indistinguishable M. simiae strains from tap water to which they were routinely exposed., Conclusions: This represents an outbreak of M. simiae colonization with one nosocomial infection. It is only the second time that M. simiae has been recovered from hospital tap water and its first presentation in municipal water. This study raises issues about the need and feasibility of eliminating or avoiding exposure to M. simiae from tap water.

Background: Effective virological suppression with HAART is dependent on strict adherence to therapy. Compliance with therapy is influenced by clinical and psychosocial factors., Method: We performed a retrospective study investigating determinants of effective virological suppression, defined as <400 RNA at 11-13 months of HAART, in an urban indigent population. The study included 366 new patients presenting for care to the Thomas Street Clinic, Houston, Texas, between April and December 1998. Median age, CD4 count, and viral load (VL) of the study population were 37.5 years, 189 cells/mm(3), and 53,000, respectively. Thirty-nine percent had AIDS, 20% had cocaine-positive drug screens, and 64% were antiretroviral naïve. Two hundred and sixty-seven patients were started on HAART. Thirty-four percent showed virological suppression., Results: In multivariate analysis, adherence to HAART, care by experienced primary provider, baseline VL <100,000 copies/mL, age >35 years, and no active substance use were associated with virological suppression. Rates of virological suppression with HAART are unacceptably low in this urban indigent population., Conclusion: Low rates of virological suppression are primarily due to lack of adherence rather than late utilization of care among ethnic minorities. Single protease-inhibitor-based antiretroviral therapy does not appear to be highly active in this patient population.

Molecular profiling of Mycobacterium tuberculosis isolates has improved recognition of tuberculosis case clusters, but the determinants of cluster size are unknown. We hypothesized that longer duration of symptoms prior to initiation of tuberculosis therapy would be associated with increased cluster size. All patients with tuberculosis in Harris County, Texas, identified between 10/1/95 and 12/31/97 through a prospective population-based project were interviewed, had their medical records reviewed, and had M. tuberculosis isolates molecularly characterized. There were 506 symptomatic, evaluable patients in 74 clusters, ranging in size from 2 patients (32 clusters) to 61 patients (1 cluster). The median duration of symptoms was 46 days (range, 1-471 days). There was no association between the log-transformed duration of symptoms and cluster size in univariate or multivariate analysis. In multivariate analysis, age and HIV coinfection were inversely related to cluster size, but only weakly. The size of molecularly defined clusters of tuberculosis was not related to the duration of symptoms of most patients who belonged to clusters.

Objective: To evaluate the covariates associated with extrathoracic tuberculosis lymphadenitis (ETBL) among adult HIV-seronegative patients., Methods: Enrollees were interviewed for TB risk assessment, their medical records were reviewed, and their Mycobacterium tuberculosis isolates underwent molecular characterization. Between 1 October 1995 and 30 September 1999, HIV-negative patients with ETBL were compared with other HIV-negative TB patients., Results: We identified 73 ETBL cases (5%) out of a total of 1371 adult HIV-negative enrollees. Significant variables predicting ETBL in the univariate analysis included age < 45 years, female sex, Asian ethnicity, foreign birth, BCG vaccination, and infection with a M. tuberculosis isolate identified in major genetic group 1. Further analysis by birth country revealed increased ETBL risk for persons from countries other than the Americas and with a TB incidence > 25 per 100 000 per year. The multivariate model demonstrated increased risk for ETBL for patients of female sex (OR = 2.6, P < 0.01) and birth in Africa or South-east Asia (OR = 4.8; P = 0.03 and OR = 33.6; P = 0.01, respectively)., Conclusions: In adult HIV-negative patients, ETBL occurs more frequently in females and in immigrants from countries other than the Americas; persons from India, South-east Asia and the Eastern Mediterranean exhibited the highest risk among these regions.

Interleukin (IL)-8 is involved in the pathogenesis of human tuberculosis (TB). However, the contribution of polymorphisms of the IL-8 gene and its receptor genes CXCR-1 and CXCR-2 to human TB susceptibility remains untested. In a case-control study, white subjects with TB disease were more likely to be homozygous for the IL-8 -251A allele, compared with control subjects (odds ratio [OR], 3.41; 95% confidence interval [CI], 1.52-7.64). African Americans with TB also showed an increased odds of being homozygous for this allele (OR, 3.46; 95% CI, 1.48-8.08). To exclude population artifacts in the case-control study, a separate analysis that used a transmission-disequilibrium test with 76 informative families confirmed that the IL-8 -251A allele was preferentially transmitted to TB-infected children (P=.02). CXCR-1 and CXCR-2 did not demonstrate significant associations with TB susceptibility. These data suggest that IL-8 is important in the genetic control of human TB susceptibility.

Ethnic minority, female, and drug-using patients may be less likely to receive highly active antiretroviral therapy (HAART), despite its proven benefits. We reviewed the medical records of a consecutive population of 354 patients entering care in 1998 at the Thomas Street Clinic, an academically affiliated, public, HIV-specialty clinic in Houston, to determine the factors associated with not receiving HAART as recorded in pharmacy records. Ninety-two patients (26.0%) did not receive HAART during at least 6 months of follow-up. Patients who did not receive HAART were more likely to be women and to have missed more than two physician appointments and were less likely to have a CD4 count <200 cells/microL or a viral load > or = 10 copies/mL. In multivariate logistic analysis, missed appointments (OR = 5.85, p<.0001), female sex (OR = 2.53, =.001), and CD4 count > or = 200 cells/microL (OR = 2.50, p=.001) were independent predictors of not receiving HAART. More than half the patients who never received HAART never returned to the clinic after their first appointment. Among patients new to care, women and those with poor appointment adherence were less likely to receive HAART. Efforts to improve clinic retention and further study of the barriers to HAART use in women are needed.

Various species of nontuberculous mycobacteria are known to cause nosocomial pseudo-outbreaks, but there have been no detailed reports of nosocomial Mycobacterium simiae pseudo-outbreaks. From April 1997 through February 2001, we recovered 65 M. simiae isolates from 62 patients at a community teaching hospital in Houston, Texas. The organism was grown in various water samples obtained in the hospital building and in professional building 1 but not in professional building 2, which has a separate water supply system. Thirty-one environmental and human outbreak-related M. simiae isolates had indistinguishable or closely related patterns on pulsed-field gel electrophoresis and were considered clonal. M. simiae can be a cause of nosocomial pseudo-outbreaks. The reservoir for this pseudo-outbreak was identified as a contaminated hospital water supply.

Setting: Houston Tuberculosis Initiative (HTI) and Baylor College of Medicine, Houston, Texas., Objective: To further explore the association between the polymorphisms of NRAMP1 and human susceptibility/resistance to tuberculosis (TB), specifically to determine whether the reported association shown for blacks and Asians holds true for Caucasian populations., Design: In a case-control study, 135 adult Caucasian TB patients and 108 adult Caucasian HIV-seronegative non-TB controls were analyzed for the association between the polymorphisms in NRAMP1 gene and clinical TB., Results: Heterozygote at 5'(GT)n, a dinucleotide repeat polymorphism in the promoter of NRAMP1, was observed at significantly higher frequencies among HIV-negative patients with pulmonary TB (41.6%; OR 2.02; 95%CI 1.11-3.64), extra-pulmonary TB (66.7%; OR 4.80; 95%CI 1.34-17.15), and HIV-seropositive TB patients (50%; OR 3.77; 95%CI 1.33-10.66) in comparison with the controls (27.8%). Homozygotes (GT)(10,10) were over-represented among HIV-positive TB patients (18.2%; OR 6.86; 95%CI 1.55-30.21) compared to the controls (5.5%)., Conclusion: These findings suggest that the 5'(GT)n polymorphism of NRAMP1 modifies TB susceptibility in this Caucasian population, and could possibly be related to the site of infection among HIV-negative individuals and HIV-coinfected TB.

Objective: Descriptive study of molecular epidemiologic patterns of tuberculosis cases among ethnic minorities in Houston, Texas., Design: Population-based, prospective, active surveillance, and molecular epidemiology study., Patients: Tuberculosis cases reported to the City of Houston Tuberculosis Control Office between October 1995 and September 1998., Results: During the study period, 1,139 culture-positive patients were enrolled for whom isolates of their culture specimen were available. Of these, 910 were part of an ethnic minority. Molecular characterization identified 689 of 1,139 isolates to be clonally related. Factors significantly associated with tuberculosis strain clustering in a multivariable logistic regression analysis were: birth in the United States, a history of homelessness, infection with the human immunodeficiency virus (HIV), pulmonary disease, infection with a tuberculosis strain from principal genetic group 1 or 3, living in a residence with five or more persons present, and use of public transportation more than once weekly. Asian ethnicity and increasing age were associated with decreased odds of clustering., Conclusions: Ethnicity was not a significant covariate for strain clustering after adjustments for factors related to socio-economic status.

Background: Isoniazid-resistant tuberculosis (INHr-TB) can be treated successfully with several treatment regimens. However, the optimal regimen and duration are unclear., Study Objective: To analyze the efficacy of treatment regimens used for INHr-TB in the southeastern Texas region., Design: Retrospective cohort study., Setting: Health-care facilities reporting tuberculosis (TB) patients in the Houston and Tyler areas., Subjects: All patients reported to have INHr-TB from 1991 to 1998. Exclusion criteria included poor compliance, additional first-line drug-resistance (except aminoglycosides), and death before completion of 1 month of treatment., Measurements and Results: Main treatment outcomes were treatment failure, relapse, and TB-related death. Fifty-three of 83 patients were included in the study; aminoglycoside resistance coexisted in 37.5% of isolates. Seven types of treatment regimens were identified. Eighteen patients (34%) received rifampin, pyrazinamide, and ethambutol thrice weekly for 9 months. Four patients (7.5%) had a total effective treatment duration of < 9 months. Thirty patients (56.6%) and 16 patients (30.2%) received thrice-daily and daily treatment regimens, respectively. Forty-nine patients achieved sputum conversion. Treatment failure and death occurred in one patient (1.9%). Three patients (5.7%) experienced relapses. There was a significant difference in total effective treatment time between patients with and without relapses (8.3 +/- 1.1 months vs 11.1 +/- 2.1 months; p < 0.02). Twice-weekly treatment regimens were associated with relapse (p = 0.05)., Conclusions: Several treatment regimens were prescribed for INHr-TB in southeastern Texas. INHr-TB treatment durations were > 7 months, and treatment regimen efficacy was adequate. Twice-weekly treatment was associated with relapse, whereas thrice-weekly and daily treatments performed similarly. A prospective study with different treatment durations is needed to determine the optimal treatment regimen for patients with INHr-TB.

The proportion of foreign-born tuberculosis patients in the United States is increasing. To analyze the epidemiology of tuberculosis in foreign-born people, culture-positive patients with tuberculosis in Houston, Texas, were interviewed from October 1995 through September 1998, and their isolates were molecularly characterized. Of the 1131 patients included in the study, 795 (70.3%) were US born and 336 (29.7%) were foreign born. The decrease in tuberculosis case rate among US-born people was 3.5 times that of foreign-born people. Significantly more US-born than foreign-born patients belonged to strain clusters (71.3% vs. 29.5%; P<.001). Risk factors associated with strain clustering were as follows: black ethnicity, low income, and homelessness in US-born patients and homelessness in foreign-born patients. Isolates from foreign-born patients were more likely to be resistant to >/=1 drug (15.4% vs. 8.4%; P=.001) and to be multidrug resistant (2.4% vs. 0.7%; P=.027) than isolates from US-born patients. These observations warrant increased emphasis on this distinct subpopulation of tuberculosis patients.

Population-based analysis of Mycobacterium tuberculosis transmission in Houston, Tex., over 5 years identified 377 patients infected with an isolate containing one to four copies of IS6110. The isolates were analyzed by spoligotyping and assigned to one of three major genetic groups based on nucleotide polymorphisms in codons katG 463 and gyrA 95. Prospectively obtained patient interviews were reviewed to assess epidemiologic links between apparently clustered patients. A total of 13 groups of isolates with the same IS6110 profile were identified, representing 326 of the 377 patients (86.5%; range 2 to 113 patients). In contrast, 28 groups of isolates containing 334 patients (88.6%) had the same spoligotype (range, 2 to 143 patients). Combination of IS6110 profile and spoligotype data identified 31 clusters with 300 patients (79.6%; range, 2 to 82 patients). All 377 isolates belonged to major genetic group 1 (77 patients) or genetic group 2 (300 patients); no major genetic group 3 isolates were identified. Among the 228 patients interviewed, 33 patients (14.5%) were directly linked to another patient in the same cluster. Possible epidemiologic links were also found among 11 patients. Moreover, many clusters consisted of individuals with the same ethnicity. In conclusion, we confirmed that IS6110 profiling and spoligotyping together provide enhanced molecular discrimination of M. tuberculosis isolates with low copy numbers of IS6110. Identification of epidemiologic links among some of the patients verified that the combination of these two methods reliably indexes tuberculosis transmission.

Mycobacterium tuberculosis isolates (n = 1,429) from 1,283 patients collected as part of an ongoing population-based tuberculosis epidemiology study in Houston, Texas, were analyzed by spoligotyping and IS6110 profiling. The isolates were also assigned to one of three major genetic groups on the basis of nucleotide polymorphisms located at codons 463 and 95 in the genes (katG and gyrA) encoding catalase-peroxidase and the A subunit of DNA gyrase, respectively. A total of 225 spoligotypes were identified in the 1,429 isolates. There were 54 spoligotypes identified among 713 isolates (n = 623 patients) assigned to 73 IS6110 clusters. In addition, among 716 isolates (n = 660 patients) with unique IS6110 profiles, 200 spoligotypes were identified. No changes were observed either in the IS6110 profile or in the spoligotype for the 281 isolates collected sequentially from 133 patients. Five instances in which isolates with slightly different spoligotypes had the same IS6110 profile were identified, suggesting that in rare cases isolates with different spoligotypes can be clonally related. Spoligotypes correlated extremely well with major genetic group designations. Only three very similar spoligotypes were shared by isolates from genetic groups 2 and 3, and none was shared by group 1 and group 2 organisms or by group 1 and group 3 organisms. All organisms belonging to genetic groups 2 and 3 failed to hybridize with spacer probes 33 to 36. Taken together, the results support the existence of three distinct genetic groups of M. tuberculosis organisms and provide new information about the relationship between IS6110 profiles, spoligotypes, and major genetic groups of M. tuberculosis.

Limited data suggest that measures to reduce tuberculosis transmission should be based on locations rather than on personal contacts. Molecular epidemiologic methods (analysis of IS6110 patterns, spoligotypes, variable numbers of tandem DNA repeats, and automated DNA sequence data) identified a cohort of 48 persons who were infected with progeny of the same Mycobacterium tuberculosis strain. Epidemiologic investigation documented that a large proportion of the patients were gay white human immunodeficiency virus-positive men. Most practiced barhopping, an activity that involved patronizing many bars in the same neighborhood each night. Few subjects were directly linked to more than 1 or 2 other persons by conventional investigation methods, which shows that the transmission dynamics were unusually complex compared with most previously described episodes of strain spread. The data support the concept that identification of locations where pathogen dissemination likely occurs may provide additional strategies for targeted tuberculosis control.