Detection of latent tuberculosis infection among laboratory personnel at a University Hospital in Eastern Saudi Arabia using an interferon gamma release assay

SummaryBackground/aimsA few recent reports have demonstrated an elevated prevalence of latent tuberculosis infection (LTBI) among laboratory personnel. We sought to evaluate the prevalence of LTBI among laboratory personnel using the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay and to assess the risk factors associated with positive test results.MethodsThe study population included laboratory personnel who were working in the routine diagnostic laboratories of different departments of a university hospital. Subjects were interviewed using a standardized questionnaire that assessed information related to risk factors for LTBI and underwent the QFT-GIT assay.ResultsPositive QFT-GIT tests results were detected in 19.4% (26/134) of the laboratory personnel. The following factors were significantly associated with positive QFT-GIT results: age≥30 years [odds ratio (OR): 4.741, 95% CI: 1.41–17.50, P=0.004]; duration of employment in the healthcare profession >10 years (P<0.0001); and non-Saudi nationality (OR: 21.67, 95% CI: 6.69–73.94, P<0.0001).ConclusionThese data highlight the need for effective institutional TB infection control plans. Additionally, our data reinforce the necessities of pre-employment and regular LTBI screening of laboratory personnel and the importance of offering preventive therapies to positive subjects to prevent the progression to active disease

Active Tuberculosis among Homeless Persons, Toronto, Ontario, Canada, 1998–2007

While tuberculosis (TB) in Canadian cities is increasingly affecting foreign-born persons, homeless persons remain at high risk. To assess trends in TB, we studied all homeless persons in Toronto who had a diagnosis of active TB during 1998–2007. We compared Canada-born and foreign-born homeless persons and assessed changes over time. We identified 91 homeless persons with active TB; they typically had highly contagious, advanced disease, and 19% died within 12 months of diagnosis. The proportion of homeless persons who were foreign-born increased from 24% in 1998–2002 to 39% in 2003–2007. Among foreign-born homeless persons with TB, 56% of infections were caused by strains not known to circulate among homeless persons in Toronto. Only 2% of infections were resistant to first-line TB medications. The rise in foreign-born homeless persons with TB strains likely acquired overseas suggests that the risk for drug-resistant strains entering the homeless shelter system may be escalating

Referrals for positive tuberculin tests in new health care workers and students: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>Documentation of test results for latent tuberculosis (TB) infection is important for health care workers and students before they begin work. A negative result provides a baseline for comparison with future tests. A positive result affords a potential opportunity for treatment of latent infection when appropriate. We sought to evaluate the yield of the referral process for positive baseline tuberculin tests, among persons beginning health care work or studies.</p> <p>Methods</p> <p>Retrospective cohort study. We reviewed the charts of all new health care students and workers referred to the Montreal Chest Institute in 2006 for positive baseline tuberculin skin tests (≥10 mm). Health care workers and students evaluated for reasons other than positive baseline test results were excluded.</p> <p>Results</p> <p>630 health care students and workers were evaluated. 546 (87%) were foreign-born, and 443 (70%) reported previous Bacille Calmette-Guérin (BCG) vaccination. 420 (67%) were discharged after their first evaluation without further treatment. 210 (33%) were recommended treatment for latent TB infection, of whom 165 (79%) began it; of these, 115 (70%) completed adequate treatment with isoniazid or rifampin. Treatment discontinuation or interruption occurred in a third of treated subjects, and most often reflected loss to follow-up, or abdominal discomfort. No worker or student had active TB.</p> <p>Conclusions</p> <p>Only a small proportion of health care workers and students with positive baseline tuberculin tests were eligible for, and completed treatment for latent TB infection. We discuss recommendations for improving the referral process, so as to better target workers and students who require specialist evaluation and treatment for latent TB infection. Treatment adherence also needs improvement.</p

Interventions to improve contact tracing for tuberculosis in specific groups and in wider populations: an evidence synthesis

Background The tracing and screening of people who have had contact with an active case of tuberculosis (TB) is an important element of TB control strategies. Objectives This study aimed to carry out a review of evidence regarding TB contact tracing, with a particular emphasis on research that was applicable to TB contact tracing in specific population groups in the UK. Design An evidence synthesis of literature of any study design on TB contact tracing in developed countries was carried out. Setting Any setting. Population Individuals found to have active TB disease, and people who have come into contact with them. Interventions Contact-tracing investigations. Main outcome measures Any outcome related to TB infection, contact investigations and/or the views of staff, people with TB disease, or their contacts. Data sources Searches for research published 1995 onwards were undertaken in the following databases: MEDLINE via Ovid SP, EMBASE via Ovid SP, EconLit via Ovid SP, PsycINFO via Ovid SP, Social Policy and Practice via Ovid SP, Cumulative Index to Nursing and Allied Health Literature via EBSCOhost, Science and Social Science Citation Indices via Web of Science and The Cochrane Library via Wiley Online Library. Review methods The study comprised a review of TB contact tracing in specific population groups and a review in wider populations. A narrative synthesis was completed and a logic model was developed from the literature. Results There were 112 articles in the review: 23 related to specific populations and 89 related to wider populations. The literature was of limited quality, with much general description of investigations. We identified only two (uncontrolled) studies that could be considered evaluative. Although the limitations of the evidence should be recognised, the review suggested the following: the value of a location-based approach, working with local communities and the media, partnership working, using molecular epidemiological testing, ensuring adequate systems and addressing fear of stigma. The literature on investigations for specific populations has much concordance with that reporting findings from wider population groups. The recognised limitations of conventional investigation methods may, however, be exacerbated in specific populations. Limitations The English-language inclusion criterion may have limited the breadth of countries represented. A meta-analysis was not possible owing to the nature of the literature. Relevant studies may have been missed by our searches, which used terminology relating to contact tracing rather than to active case finding or screening. Conclusions The review identified a sizeable volume of literature relating to contact investigations. However, it is currently predominantly descriptive, with little evaluative work underpinning investigations in either specific or wider populations. Our findings are, therefore, based on limited evidence. Further research is required if robust conclusions are to be made. Future work Research should further explore the development of measures that can be used to compare the effectiveness of different contact investigations, in studies using evaluative designs