Perceptions and behaviors of learner engagement with virtual educational platforms.

BACKGROUND: The COVID-19 pandemic has increased utilization of educational technology for surgical education. Our aim was to determine attitudes and behaviors of surgical education champions towards virtual educational platforms and learner engagement. METHODS: An electronic survey was distributed to all Association of Surgical Education members addressing i) methods of engagement in virtual learning ii) ways to improve engagement and iii) what influences engagement. Stratified analysis was used to evaluate differences in responses by age, gender, level of training and specialty. RESULTS: 154 ASE members completed the survey (13% response rate). 88% respondents accessed virtual learning events at home. Most (87%) had joined a virtual learning event and then participated in another activity. 1 in 5 who did this did so "always" or "often". Female respondents were more likely than males to join audio and then participate in another activity (62.3% v 37.7%, p = 0.04). CONCLUSIONS: Virtual platforms do not automatically translate into increased learner engagement. Careful design of educational strategies is essential to increase and maintain learner engagement when utilizing virtual surgical education.

A major subgroup of Beijing family Mycobacterium tuberculosis is associated with multidrug resistance and increased transmissibility.

This study investigated further the association between the Beijing family Mycobacterium tuberculosis circulating in rural China and anti-tuberculosis (TB) drug resistance. In total, 351 M. tuberculosis isolates were collected through a population-based epidemiological study, 223 (63·5%) of which were resistant to at least one anti-TB drug, including 53 (15·1%) multidrug-resistant (MDR) isolates. Spoligotyping found 243 isolates (69·2%) that belonged to the Beijing family. A major subgroup of the Beijing family identified by mycobacterial interspersed repetitive unit (MIRU) genotyping (223325173533), showed significantly higher frequencies of MDR (44·7% vs. 13·7%, OR 6·18, 95% CI 2·68-14·23), katG and rpoB mutations (31·6% vs. 9·3%, OR 4·27, 95% CI 1·86-9·80), and being clustered by IS6110 RFLP genotyping (60·5% vs. 21·0%, OR 6·14, 95% CI 2·82-13·37) in comparison with other Beijing family isolates. Our data suggest that MIRU genotype 223325173533 of the Beijing family is associated with MDR and increased transmissibility.

Assessing learner engagement with virtual educational events: Development of the Virtual In-Class Engagement Measure (VIEM).

BACKGROUND: The COVID-19 pandemic has necessitated virtual education, but effects on learner engagement are unknown. We developed a virtual in-class engagement measure (VIEM) to assess learner engagement in online surgical education events. METHODS: Using the STROBE, an observer collected tool to document student engagement, as a template an ASE committee workgroup developed the VIEM. The VIEM had two parts: observer assessment and learner self-assessment of engagement. Trained observers collected engagement data from two institutions using the VIEM. Surgical attendings, fellows and residents were observed during virtual learning events. Educator attitudes towards online teaching were also assessed via survey. RESULTS: 22 events with 839 learners were observed. VIEM distinguished between sessions with low and high engagement. 20% of learners pretended to participate. Half of instructors were comfortable with virtual teaching, but only 1/3 believed was as effective as in-person. 2/3 of teachers believed video learners were more engaged than audio learners. CONCLUSIONS: Virtual platforms do not automatically translate into increased engagement. Standard tools such as VIEM may help with assessment of engagement during virtual education.

Suitability of Estimated Glomerular Filtration Rate for Live Kidney Donor Selection.

INTRODUCTION: The assessment of the glomerular filtration rate (GFR) in kidney donor candidates is required for determining donor candidate acceptability. This assessment can be done using an estimated GFR (eGFR) or a measured GFR (mGFR). The primary objective of the present study was to compare, in healthy adult kidney donor candidates, GFR measured by the clearance of iothalamate to GFR estimated using the Chronic Kidney Disease Epidemiology Collaboration equation and to determine if eGFR was a suitable stand-alone assessment. A secondary objective was to explore demographic factors that affect the relationship of the eGFR and the mGFR. METHODS: A retrospective review of kidney donor candidates' records at the J. C. Walter, Jr., Transplant Center, Houston Methodist Hospital, from January 2013 to March 2016 was undertaken. GFR was measured by the plasma clearance of radioisotopic iothalamate and estimated using the Chronic Kidney Disease Epidemiology Collaboration equation. RESULTS: The median mGFR was 108 mL/min/1.73 m2. The eGFR underestimated the mGFR by 11.5%. The underestimation was greatest in subjects with an mGFR of ≥90 mL/min/1.73 m2. The eGFR overestimated the mGFR in donor candidates of black race. CONCLUSIONS: The Chronic Kidney Disease Epidemiology Collaboration eGFR can be used for screening potential kidney donors restricting the use of iothalamate (mGFR) to those donors with an eGFR below the transplant centers' acceptable GFR threshold for donation, thereby effecting cost savings and greater donor convenience. The eGFR in black donor candidates should be used with caution.

Transplantation for Hepatocellular Carcinoma: Is There a Tumor Size Limit?

BACKGROUND: The advent of tumor-size-based criteria (Milan and University of California, San Francisco [UCSF]) for the transplantation of hepatocellular carcinomas (HCC) has facilitated tumor patients' access to transplantation. Recent success in transplanting patients with larger tumors (beyond UCSF) necessitates an understanding of the patient, the tumor, and biological criteria that determine successful outcomes for HCC transplantation across all size criteria. METHODS: We analyzed 11,928 patients who received OLT between 2002 and 2013 from the United Network for Organ Sharing Standard Transplant Analysis and Research file. Clinical outcomes were compared by tumor size at transplant; Milan (n = 11,555), beyond Milan within UCSF (n = 291), and beyond both Milan and UCSF (n = 82). A statistical analysis was conducted to determine the factors impacting survival. RESULTS: There were no statistically significant differences in the 1-, 3-, and 5-year survival rates between the 3 patient groups (within Milan 91.1%, 74.8%, and 60.3%; beyond Milan within UCSF, 92.7%, 71.1%, and 51.6%; and beyond Milan and UCSF 95.8%, 75.9%, and 58.1%). In a multivariate analysis, factors significantly affecting survival included, AA race, AFP >3000, and hepatitis C infection, while age, diabetes and largest tumor diameter had a more modest impact. Total tumor burden and time to transplantation were not significant predictors of survival. CONCLUSIONS: These data indicate that, based on current clinical selection criteria, a small number of large tumors can be successfully treated by transplantation and points to the need to include markers of HCC biologic behavior beyond size and tumor burden to transplant criteria.

No association between the +874T/A single nucleotide polymorphism in the IFN-gamma gene and susceptibility to TB.

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.

Tuberculosis infection in drug users: interferon-gamma release assay performance.

SETTING: An inner city neighborhood in Houston, Texas, known for a high rate of drug use. OBJECTIVE: To determine the prevalence of latent tuberculosis infection (LTBI) using the QuantiFERON-TB Gold (QFT-G) test, the TSPOT.TB test and the tuberculin skin test (TST) in drug users and to evaluate the performance of the QFT-G and TSPOT.TB tests vs. the TST. DESIGN: Cross-sectional study. Bivariate and multivariate logistic regression analyses were used to determine risks associated with each test outcome. RESULTS: The prevalence of LTBI in 119 drug users studied was 28% by TST and 34% by QFT-G and T-SPOT.TB. Kappa statistics indicated fair to moderate concordance between QFT-G and TSPOT.TB vs. TST. About one-fifth of the population that tested negative with TST was positive with either QFT-G or T-SPOT.TB. On multivariate analysis, the likelihood of testing QFT-positive or T-SPOT.TB-positive increased by 8% and 6%, respectively, for every year of age; TST positivity was associated with smoking crack at home; being Caucasian or having a history of alcohol use was positively associated with a positive T-SPOT.TB test. CONCLUSION: Interferon-gamma release assays (IGRAs) are superior to the TST in drug users with a higher prevalence of LTBI. Future studies need to assess the predictive value of IGRAs on the progression from LTBI to active TB in high-risk populations.

Clinical and bacteriological characteristics associated with clustering of multidrug-resistant tuberculosis.

SETTING: The impact of the genetic characteristics of Mycobacterium tuberculosis on the clustering of multidrug-resistant tuberculosis (MDR-TB) has not been analyzed together with clinical and demographic characteristics. OBJECTIVE: To determine factors associated with genotypic clustering of MDR-TB in a community-based study. DESIGN: We measured the proportion of clustered cases among MDR-TB patients and determined the impact of clinical and demographic characteristics and that of three M. tuberculosis genetic characteristics: lineage, drug resistance-associated mutations, and rpoA and rpoC compensatory mutations. RESULTS: Of 174 patients from California and Texas included in the study, the number infected by East-Asian, Euro-American, Indo-Oceanic and East-African-Indian M. tuberculosis lineages were respectively 70 (40.2%), 69 (39.7%), 33 (19.0%) and 2 (1.1%). The most common mutations associated with isoniazid and rifampin resistance were respectively katG S315T and rpoB S531L. Potential compensatory mutations in rpoA and rpoC were found in 35 isolates (20.1%). Hispanic ethnicity (OR 26.50, 95%CI 3.73-386.80), infection with an East-Asian M. tuberculosis lineage (OR 30.00, 95%CI 4.20-462.40) and rpoB mutation S531L (OR 4.03, 95%CI 1.05-23.10) were independent factors associated with genotypic clustering. CONCLUSION: Among the bacterial factors studied, East-Asian lineage and rpoB S531L mutation were independently associated with genotypic clustering, suggesting that bacterial factors have an impact on the ability of M. tuberculosis to cause secondary cases.

Characteristics and costs of multidrug-resistant tuberculosis in-patient care in the United States, 2005-2007.

OBJECTIVE: A population-based study of 135 multidrug-resistant tuberculosis (MDR-TB) patients reported to the Centers for Disease Control and Prevention (CDC) during 2005-2007 found 73% were hospitalized. We analyzed factors associated with hospitalization. METHODS: We assessed statistically significant multivariable associations with US in-patient TB diagnosis, frequency of hospitalization, length of hospital stay, and in-patient direct costs to the health care system. RESULTS: Of 98 hospitalized patients, 83 (85%) were foreign-born. Blacks, diabetics, or smokers were more likely, and patients with disseminated disease less likely, to receive their TB diagnosis while hospitalized. Patients aged ⩾65 years, those with the acquired immune-deficiency syndrome (AIDS), or with private insurance, were hospitalized more frequently. Excluding deaths, length of stay was greater for patients aged ⩾65 years, those with extensively drug-resistant TB (XDR-TB), those residing in Texas, those with AIDS, those who were unemployed, or those who had TB resistant to all first-line medications vs. others. Average hospitalization cost per XDR-TB patient (US$285 000) was 3.5 times that per MDR-TB patient (US$81 000), in 2010 dollars. Hospitalization episode costs for MDR-TB rank third highest and those for XDR-TB highest among the principal diagnoses. CONCLUSIONS: Hospitalization was common and remains a critical care component for patients who were older, had comorbidities, or required complex management due to XDR-TB. MDR-TB in-patient costs are among the highest for any disease.

Yield of chest radiograph in tuberculosis screening for HIV-infected persons at a district-level HIV clinic.

SETTING: An Hoa Clinic, a district-level human immunodeficiency virus (HIV) clinic in Ho Chi Minh City, Viet Nam. OBJECTIVE: To assess the performance of chest radiograph (CXR) in screening for pulmonary tuberculosis (PTB) among HIV-infected individuals and identify misdiagnosed opportunities. DESIGN: This cross-sectional study was conducted in 397 HIV-infected patients consecutively enrolled at the An Hoa Clinic in Ho Chi Minh City, Viet Nam, from August 2009 to June 2010. The performance of CXR in TB screening was assessed based on its sensitivity, specificity, positive likelihood ratio and negative likelihood ratio. RESULTS: Symptom screening alone missed 50% of PTB cases. The combination of CXR and symptom screening yielded an additional 28.6% (8/28) in PTB screening as compared with symptom screening alone, and should be applied routinely, especially in high TB prevalent settings. CONCLUSION: CXR is a good predictor for PTB even in HIV-infected individuals. The combination of CXR and screening for common TB symptoms considerably improved the sensitivity of detecting active PTB in people living with HIV. If available, routine sputum culture and the World Health Organization-endorsed Xpert(®) MTB/RIF assay should be implemented to achieve a more accurate diagnosis.

Cryptosporidiosis in Houston, Texas. A report of 95 cases.

Cryptosporidiosis is an important cause of diarrhea. We identified 95 patients with cryptosporidiosis over a 6-year period in our county hospital system, including 9 children and 86 adults infected with the human immunodeficiency virus (HIV). Risk factors included male-to-male sexual practices and Hispanic race. Diarrhea, weight loss, and gastrointestinal complaints were the most common symptoms at presentation. Among the HIV-infected adults, 20 (23%) developed biliary tract disease. Biliary involvement was associated with low CD4 counts. Treatment with paromomycin and antimotility agents was effective in reducing diarrheal symptoms in 54 of 70 (77%) patients with the acquired immunodeficiency syndrome (AIDS), although there was a high rate of relapse. Paromomycin did not prevent the development of biliary disease. Biliary disease responded to cholecystectomy or sphincterotomy with stent placement. Though often a cause of morbidity, cryptosporidiosis was only rarely the cause of death, even among patients with HIV. Cryptosporidiosis continues to be an important medical problem even in developed-countries. Current methods of prevention and treatment are suboptimal.

Bacteremic and nonbacteremic pneumococcal pneumonia. A prospective study.

We prospectively identified cases of pneumococcal pneumonia and used stringent criteria to stratify them into bacteremic and nonbacteremic cases. Although patients were distributed among racial groups in proportion to all patients seen at this medical center, the proportion of African-Americans with bacteremic disease was significantly increased. All patients had at least 1 underlying condition predisposing to pneumococcal infection, and most had several. Although the mean number of predisposing factors was greater among bacteremic patients than nonbacteremic patients, only alcohol ingestion was significantly more common. Nearly one-third of patients had substantial anemia (hemoglobin < or = 10 g/dL) on admission, which may have predisposed to infection. In the case of other laboratory abnormalities, such as albumin, creatinine, and bilirubin, it was difficult to determine which abnormality might have predisposed to pneumococcal infection and which might have resulted from it. The radiologic appearance was varied. Airspace consolidation and air bronchogram on chest X-ray were highly associated with bacteremic disease, as was the presence of pleural effusion. Although the Pneumonia Patient Outcomes Research Team (PORT) risk score was a predictor of mortality, it did not help to predict the presence of bacteremia in an individual case. Most patients who died in the first week in hospital were bacteremic, and a high PORT risk score with bacteremia reliably predicted a high likelihood of a fatal outcome. Eleven patients had extrapulmonary disease with meningitis, empyema, and septic arthritis predominating; all of these patients were bacteremic. The antibiotic susceptibility of our strains correlated well with those that have been reported in the United States during the years of this study. The use of numerous antibiotics of different classes in many patients, especially those who were the most ill, precluded analysis of outcome based on antibiotic therapy. Only 17 patients had been vaccinated. Since nearly all patients had conditions for which pneumococcal vaccine is recommended and more than one-third had been hospitalized in the preceding 6 months, the low rate of vaccination can be regarded as a missed opportunity to administer a potentially beneficial vaccine.

Treatment of isoniazid-resistant tuberculosis in southeastern Texas.

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 role of frozen section, gender, age, and tumor size in the differentiation of follicular adenoma from carcinoma: a meta-analysis.

BACKGROUND: The purpose of this study was to reanalyze modern trials and use meta-analysis to determine how well frozen section gender, age, and tumor size could differentiate follicular adenoma from follicular carcinoma. METHOD: Inclusion criteria were studies where patients had a permanent pathologic diagnosis of follicular adenoma or follicular carcinoma and underwent frozen section or had clinical features recorded. Data were pooled, and the random effects model of meta-analysis was used. A probability value of less than.05 was considered significant. RESULTS: Nineteen studies were included (n = 3486 patients). Frozen section was evaluated in 11 studies (n = 2204 patients). Frozen section had an 87% sensitivity, a 48% specificity, a 92% and 35% positive and negative predictive value, respectively, an 82% accuracy, an odds ratio of 0.181, a 95% confidence interval (CI) of 0.07 to 0.49, and a probability value of.001. Clinical features were evaluated in 10 studies (n = 1954 patients). Of the patients with follicular carcinoma, 27.5% were male compared with patients with follicular adenoma, of whom 17.7% were male (P <.01; odds ratio, 2.17; CI 1.3-3.6; P =.003). Of the patients with follicular carcinoma, 52.2% were older than 50 years (52.2%) compared with patients with follicular adenoma, of whom 28.5% were older than 50 years (P <.001). Of patients with follicular carcinoma, 36.8% had tumors larger than 3 to 5 cm compared with patients with follicular adenoma, of whom 14.7% had tumors larger than 3 to 5 cm (P <.001; odds ratio, 3.99; CI 1.5-10.8; P =.006). CONCLUSIONS: Meta-analysis suggests that frozen section is not a specific test and cannot be used to confidently rule out follicular carcinoma. Male gender and large tumor size are significantly associated with carcinoma.

Determinants of sustained virological suppression in indigent, HIV-infected patients: is single protease inhibitor-based antiretroviral therapy truly highly active?

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.

Extrathoracic tuberculosis lymphadenitis in adult HIV seronegative patients: a population-based analysis in Houston, Texas, USA.

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.

Recurrent tuberculosis in Houston, Texas: a population-based study.

OBJECTIVE: To determine the predictors of recurrence of tuberculosis (TB), the drug resistance pattern of Mycobacterium tuberculosis strains recovered from recurrent TB patients, and the frequency of re-infection with a new M. tuberculosis strain among patients with recurrent disease. DESIGN: A population-based, retrospective case-control study using the Houston Tuberculosis Initiative database. RESULTS: We found that, among 100 patients with recurrent TB who completed adequate therapy for a first episode of TB, not receiving directly observed therapy, pulmonary disease, HIV/AIDS diagnosis, not having a family physician, being unemployed and using public transportation were predictors of recurrent disease. There was a significant increase in drug-resistant M. tuberculosis strains in the second episode of disease compared to the first episode (21.3% vs. 8.2%, P = 0.04). Exogenous re-infection with a new strain of M. tuberculosis was found to cause 24-31% of recurrent TB. CONCLUSION: Recurrent TB in Houston is associated with a significant increase in drug-resistant M. tuberculosis strains. Re-infection with a new M. tuberculosis strain causes a significant proportion of recurrent TB in an area of low TB incidence. Patients with HIV/AIDS constitute a population at increased risk of disease recurrence.

Extra-pulmonary manifestations in a large metropolitan area with a low incidence of tuberculosis.

BACKGROUND: The increases in extra-pulmonary tuberculosis (EPTB) have been largely due to human immunodeficiency virus co-infection. The rates of EPTB have remained constant despite the decline in pulmonary tuberculosis (PTB) cases. OBJECTIVE: To evaluate covariates associated with EPTB. METHODS: A 4-year cohort of EPTB patients was compared with PTB cases. Enrollees were assessed for TB risk, medical records were reviewed, and Mycobacterium tuberculosis isolates were fingerprinted. RESULTS: We identified 538 EPTB cases (28.6%) in a total of 1878 enrollees. The most common sites of infection were lymph nodes (43%) and pleura (23%). EPTB cases included 320 (59%) males, 382 (71%) patients were culture-positive, and 332 (86.9%) patient isolates were fingerprinted. Fewer EPTB than PTB patients belonged to clustered M. tuberculosis strains (58% vs. 65%; P = 0.02). A multivariate model identified an increased risk for EPTB among African Americans (OR = 1.9, P = 0.01), HIV-seropositive (OR = 3.1, P < 0.01), liver cirrhosis (OR = 2.3, P = 0.02), and age <18 years (OR = 2.0, P = 0.04). Patients with concomitant pulmonary and extra-pulmonary infections were more likely to die within 6 months of TB diagnosis (OR = 2.3, P < 0.01). CONCLUSIONS: African American ethnicity is an independent risk factor for EPTB. Mortality at 6 months is partly due to the dissemination of M. tuberculosis and the severity of the underlying co-morbidity.

The contribution of ethnicity to Mycobacterium tuberculosis strain clustering.

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.

5' dinucleotide repeat polymorphism of NRAMP1 and susceptibility to tuberculosis among Caucasian patients in Houston, Texas.

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.