An outbreak of tuberculosis occurred over a 3-year period in a medium-size community in British Columbia, Canada. The results of mycobacterial interspersed repetitive unit–variable-number ...tandem-repeat (MIRU-VNTR) genotyping suggested the outbreak was clonal. Traditional contact tracing did not identify a source. We used whole-genome sequencing and social-network analysis in an effort to describe the outbreak dynamics at a higher resolution.
Mycobacterium tuberculosis
is an important infectious disease even in developed countries with extensive control programs. This is the case in British Columbia, Canada, where the 2007 incidence rate of 6.4 cases per 100,000 population exceeded the national average of 4.7 cases per 100,000 population.
1
In May 2006, a case of smear-negative pleural tuberculosis was diagnosed in an adult in a medium-size community in British Columbia. A second case, manifested as disseminated tuberculosis, was reported in an infant in July 2006. Reverse contact tracing identified nine additional cases between August and October 2006, when the British Columbia Centre for Disease Control . . .
Background: The accurate diagnosis of latent tuberculosis infection (LTBI) is an important component of any tuberculosis control programme and depends largely on tuberculin skin testing. The ...appropriate interpretation of skin test results requires knowledge of the possible confounding factors such as previous BCG vaccination. Uncertainty about the effect of BCG vaccination on tuberculin skin testing and the strength with which recommendations are made to individual patients regarding treatment of LTBI have identified a need to analyse the available data on the effect of BCG on skin testing. A meta-analysis of the evidence for the effect of BCG vaccination on tuberculin skin testing in subjects without active tuberculosis was therefore performed. Methods: Medline was searched for English language articles published from 1966 to 1999 using the key words “BCG vaccine”, “tuberculin test/PPD”, and “skin testing”. Bibliographies of relevant articles were reviewed for additional studies that may have been missed in the Medline search. Articles were considered for inclusion in the meta-analysis if they had recorded tuberculin skin test results in subjects who had received BCG vaccination more than 5 years previously and had a concurrent control group. Only prospective studies were considered. The geographical location, number of participants, type of BCG vaccine used, type of tuberculin skin test performed, and the results of the tuberculin skin test were extracted. Results: The abstracts and titles of 980 articles were identified, 370 full text articles were reviewed, and 26 articles were included in the final analysis. Patients who had received BCG vaccination were more likely to have a positive skin test (5 TU PPD: relative risk (RR) 2.12 (95% confidence interval (CI)1.50 to 3.00); 2 TU RT23: 26.50 (95% CI 1.83 to 3.85). The effect of BCG vaccination on PPD skin test results was less after 15 years. Positive skin tests with indurations of >15 mm are more likely to be the result of tuberculous infection than of BCG vaccination. Conclusions: In subjects without active tuberculosis, immunisation with BCG significantly increases the likelihood of a positive tuberculin skin test. The interpretation of the skin test therefore needs to be made in the individual clinical context and with evaluation of other risk factors for infection. The size of the induration should also be considered when making recommendations for treatment of latent infection.
Aromatase inhibitors (AIs) decrease the production of oestrogen, decreasing stimulation of hormone receptor-positive breast cancer. Theoretically, AIs may be less effective in obese women, due to the ...greater quantity of aromatase in peripheral fatty tissue. We performed a systematic review to assess the effect of obesity on AI efficacy in breast cancer treatment. The review followed PRISMA guidelines. Studies included were interventional or observational studies with comparison groups, of postmenopausal women with hormone receptor-positive breast cancer on treatment with an AI, alone or in combination with other drugs, in which body mass index or another measure of obesity was recorded. Studies in all languages were included; if published as an abstract only, authors were contacted for further information. Outcome measures included overall survival, disease-free survival or time to progressive disease, survival from the start of therapy, mortality measures, local or distant recurrence of primary cancer and time to recurrence. Of 2,344 citations identified from five databases, eight studies met the criteria for inclusion; three randomised controlled trials and five retrospective cohort studies. Due to variability in study factors, it was not possible to perform a quantitative meta-analysis. However, the systematic review showed a trend towards a negative effect of obesity on AI efficacy. There is evidence of a negative effect of obesity on AI efficacy in postmenopausal hormone receptor-positive breast cancer, but the size of the effect cannot be assessed. More information is needed before clinical recommendations are made.
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Nearly one quarter of the global population has been infected with
Mycobacterium tuberculosis
, and there are more than 10 million new infections per year. In an open-label trial, 9 months of ...isoniazid was compared with 4 months of rifampin as therapy for latent tuberculosis infection.
Summary
Background Studies have shown the benign to malignant ratio of excised pigmented skin lesions is suboptimal in primary care.
Objectives To assess the impact of dermoscopy and short‐term ...sequential digital dermoscopy imaging (SDDI) on the management of suspicious pigmented skin lesions by primary care physicians.
Methods A total of 63 primary care physicians were trained in the use of dermoscopy and SDDI (interventions) and then recruited pigmented lesions requiring biopsy or referral in routine care by naked eye examination. They were then given a dermatoscope and the option of a SDDI instrument, and change of diagnosis and management was assessed.
Results Following the use of the interventions on 374 lesions a total of 163 lesions (43·6%) were excised or referred, representing a reduction of 56·4%. Of the 323 lesions confirmed to be benign, 118 (36·5%) were excised or referred, leading to a reduction of 63·5% (P < 0·0005) in those requiring excision or referral. The baseline naked eye examination benign to melanoma ratio was 9·5 : 1 which decreased to 3·5 : 1 after the diagnostic interventions (P < 0·0005). Of the 42 malignant lesions included in the study (34 melanoma, six pigmented basal cell carcinoma and two Bowen disease) only one in situ melanoma was incorrectly managed (patient to return if changes occur) resulting in the correct management of 97·6% and 97·1% of malignant pigmented lesions and melanoma, respectively.
Conclusions In a primary care setting the combination of dermoscopy and short‐term SDDI reduces the excision or referral of benign pigmented lesions by more than half while nearly doubling the sensitivity for the diagnosis of melanoma.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Background: While smear positive patients with tuberculosis (TB) are considered more infectious than smear negative patients, the latter can also transmit TB. Methods: In a molecular epidemiology ...study of 791 patients in the Greater Vancouver regional district, the number of episodes of TB transmission from two groups of smear negative clustered patients by RFLP (assumed to be involved in recent transmission) was estimated after assessing for potential bias. Group 1 (n = 79) included patients with pulmonary TB or pulmonary + extrapulmonary disease (PTB or PTB+EPTB); group 2 (n = 129) included all patients in group 1 + extrapulmonary cases alone. Results: In the total sample the mean (SD) age was 51 (21) years, 54.3% were male, and 17.0% of patients were clustered. Compared with smear negative patients, smear positive patients were more likely to be in a cluster (OR = 2.0, 95% CI 1.1 to 3.6) and to have had a history of ethanol abuse (OR = 2.7, 95% CI 1.0 to 6.7), diabetes mellitus (OR = 2.8, 95% CI 1.1 to 7.0), injection drug use (OR = 3.1, 95% CI 1.1 to 8.3), and to have had a previous hospital admission (OR = 8.5, 95% CI 5.1 to 14.0). The proportion of episodes of transmission from smear negative clustered patients ranged from 17.3% to 22.2% in group 1 and from 25% to 41% in group 2. Conclusion: In Greater Vancouver, smear negative cases appear responsible for at least one sixth of culture positive episodes of TB transmission.
AbstractThe experimental in-plane force-displacement response of unreinforced masonry (URM) walls with flanges (return walls) subjected to pseudo-static cyclic lateral loading is presented. Each wall ...failed in a diagonal tension mode followed by bed-joint sliding. The effect of wall flanges was an increase in the displacement capacity of the in-plane loaded wall, in comparison with an in-plane loaded wall without flanges. The measured shear strengths of the walls were compared with an analytical model for determining the limiting diagonal tension strength of the walls, with a high level of correlation. The initial stiffness of the shear walls before the effective yield was compared with the initial stiffness as determined using conventional principles of mechanics for homogeneous materials, and it was found that with some approximations the initial stiffness could be satisfactorily determined. Because the bed-joint sliding failure mechanism exhibited by the walls is a deformation-controlled action, there is further displacement capacity beyond the effective yield displacement, and it was found that the walls could sustain in-plane lateral forces to a drift of at least 0.7%. Recommendations are provided for a general force-displacement relationship, which is consistent with the experimental data and can be used for modeling URM walls and improving acceptance criteria, such as those specified in ASCE/SEI 41-06.
A national internet‐based survey of New Zealand (NZ) primary care physicians (n = 192) used the survey instrument developed by the International Cancer Benchmarking Partnership (ICBP). Practitioners ...were recruited by a range of methods assisted by NZ general practice networks and contacts. Compared to 11 other ICBP jurisdictions, direct access to diagnostic tests was more limited and took more time than in most other areas; the average wait for a test to be done and reported was 3.0 weeks for X‐rays and 8.0 for ultrasound, compared to ICBP averages of 1.6 and 4.7 weeks respectively. Forty‐five per cent of respondents could get specialist advice within 48 hr. Sixty‐six per cent were aware of NZ guidelines for cancer in primary care, and of those 44% consulted them sometimes or often. Access to tests was greater, and time required much less, in the private than the public care system. NZ respondents each answered two of five clinical vignettes, with results similar to other ICBP areas. The survey also included general practice trainees (N = 42); their results were similar to the main group. The results suggest that improvements in prompt access to diagnostic tests and referrals for suspected cancer need to be given priority in NZ.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
BACKGROUND: Many risk factors for the development of tuberculosis (TB) have been reported but have not been simultaneously assessed.OBJECTIVE: To determine the risk of developing TB associated with ...each risk factor, after adjusting for all others.METHODS: We performed a population-based,
retrospective cohort study of the contacts of TB cases recorded in British Columbia, Canada. Known risk factors for the development of TB were assessed over a 12-year period; Cox regression was used to estimate the hazard ratios (HRs) of TB, adjusting for the other factors.RESULTS: Among
33 146 TB contacts, 228 developed TB during the study period (TB rate 668 per 100 000 population, 95%CI 604-783). The main risk factors for TB development were malnutrition (HR 37.5), no treatment of latent TB infection (HR 25) or <6 months of treatment (HR 5.38), age
0-10 years (HR 7.87), being a household contact (HR 8.47) and having a tuberculin skin test induration of ≥5 mm (HR ≥4.99). Bacille Calmette-Guérin vaccination significantly reduced the risk of TB development (HR 0.32, 95%CI 0.20-0.50).CONCLUSIONS: Among contacts
of TB cases, we have identified the few factors that carry a very high risk for developing TB. These factors identify populations at highest risk and permit more effective TB control.
PDF
