We evaluated an in vitro test of cell-mediated immunity, the tuberculin gamma interferon assay, QuantiFERON-TB (QIFN), in 455 individuals from three groups: group I, 237 immigrants from high-risk countries; group II, 127 health care workers undergoing Mantoux testing; group III, 91 patients being investigated for possible active tuberculosis (79 patients) or Mycobacterium avium-Mycobacterium intracellulare complex infection (12 patients). The QIFN results were compared either to those of the Mantoux test or to microbiological and clinical diagnosis, as appropriate. In each group the correlation between the diameter of induration for the skin test and the magnitude of QIFN response was significant and of moderate strength (Spearman’s rank correlation coefficient; ρ = 0.59 to 0.61; P < 0.001). For group I, the agreement between QIFN and Mantoux results was 89% for Mantoux-negative and 64% for Mantoux-positive individuals. For group II, when ≥10-mm-diameter induration was taken as positive, the agreement was 81% for Mantoux-negative and 67% for Mantoux-positive individuals. For group III, agreement was 81% for Mantoux-negative and 86% for Mantoux-positive patients. For patients being evaluated for active tuberculosis, the performance of the Mantoux test was not statistically different from that of the QIFN assay. In patients with active tuberculosis, the assay had a sensitivity of 77%, not significantly higher for extrapulmonary than pulmonary cases (83% versus 74%). QIFN sensitivity was not significantly different for smear-negative or smear-positive cases (80% versus 71%). The QIFN assay is a potential replacement for the Mantoux test. The acceptability of these performance values and those of similar evaluations will determine the place this test will have in detecting evidence of mycobacterial infection.
It was hypothesised that the time to detect Mycobacterium tuberculosis in liquid culture of sputum from patients with pulmonary tuberculosis may be a better indicator for the duration of respiratory isolation than sputum smear status.Pre-treatment and during-treatment sputum acid-fast bacilli (AFB) smear and culture results were reviewed in 284 patients with pulmonary tuberculosis. The time to detect M. tuberculosis in liquid culture (TTD-TB) was the number of days from inoculation of the Mycobacterial Growth Indicator Tube to culture detection and visualisation of AFB.The median (interquartile range) TTD-TB for smear group 0 (no bacilli seen) was 14 (12-20) days. This value was used as the standard at which release from isolation could be permitted. In smear group 4 (.9 AFB per high-power field (hpf) in sputum specimens before treatment) patients, the TTD-TB exceeded 14 days after a median of 25 days of treatment.The current authors recommend that patients in smear groups 1 and 2 (1-9 AFB per 100 hpf and 1-9 AFB per 10 hpf in sputum specimens before treatment, respectively) receive treatment in respiratory isolation for 7 days, provided the risk of drug resistance is low. Smear group 3 (1-9 AFB per hpf) and 4 patients should receive treatment in respiratory isolation for 14 and 25 days, respectively. These criteria would have reduced the duration of respiratory isolation by 1,516 days in the 143 study participants with sputum smear-positive pulmonary tuberculosis.Provided clinical and radiographical criteria are satisfactory, use of the time to detect Mycobacterium tuberculosis in liquid culture could enable the duration of respiratory isolation to be predicted from the pre-treatment sputum smear grade. The recommendations enable isolation to end well before sputum becomes smear negative, with considerable benefits to patients and healthcare providers.
Maoris and Pacific Islanders in New Zealand have a higher asthma mortality and hospital admission rates than Europeans. To determine whether difference in asthma prevalence is the major factor underlying these differences in mortality, 2053 Auckland children aged 7-10 years (European 1084, Maori 509, Pacific Islander 460) were randomly sampled from school classes in the Auckland Urban Area, and studied by questionnaire (completed by parents) and histamine inhalation challenge to assess the provocative dose of histamine causing a 20% fall in FEV, (PD20). Maoris had the highest prevalence rates of respiratory symptoms, and Europeans had rates similar to Pacific Islanders. For "any current wheeze" for example, the prevalence in Maoris was 22-2% compared with 16 1% and 16-3% in the Europeans and Pacific Islanders. The prevalence of diagnosed asthma was similar in the three groups. When bronchial hyperresponsiveness (defined as a PD20 < 7.8 Mmol histamine) was considered, Europeans had the highest rates (20%), followed by Maoris (13%), and then Pacific Islanders (8-7%). These differences were not accounted for by differences in socioeconomic status, rates of smoking in the home, age, gender, or height. It is concluded that differences in asthma prevalence do not satisfactorily explain the mortality and admission rate differences, although the higher symptom prevalence in the Maoris could be relevant to the higher mortality rate. Maori and Pacific Island children with symptoms of asthma were less likely to be taking pwophylactic medication than European children. It is proposed that differences in management are important factors relevant to the increased mortality and morbidity from asthma in Polynesians.
Sputum and blood cultures taken before antibiotic treatment showed no growth; sputum smears for acid fast bacilli were negative, as were subsequent cultures. Erythromycin was added when four days of antibiotics resulted in no improvement. He continued to be febrile, and became increasingly hypoxaemic, with an arterial oxygen saturation of only 90% with 60% inspired oxygen (arterial oxygen tension (Pao2) 8-5 kPa; breathing air he had a Pao2 of 4.7 kPa). The radiological changes worsened.As he continued to deteriorate an open lung biopsy was performed three weeks after admission. At operation the right lung was woody with 1-5 mm firm nodules throughout. A biopsy specimen from the right middle lobe showed diffuse alveolar damage and interstitial pneumonitis, a toluidine blue stain imprint was positive for P carinii, and a Gram stain showed a moderate number of pus cells but no organisms. There was no growth from cultures for the usual bacterial pathogens, Legionella, acid fast bacilli, fungi, or cytomegalovirus. The results of an HIV antibody screen were negative and of cytomegalovirus and mycoplasma complement fixation tests only weakly positive.A clinical diagnosis of pneumocystis pneumonia was made and treatment was changed to high dose oral co-trimoxazole (four 480 mg tablets four times a day). Within 48 hours his fever had abated and his oxygen requirement had fallen so that 3 litres/min oxygen by nasal prongs maintained an arterial Pao2 of l0*1 kPa. He completed three weeks of co-trimoxazole treatment and continued to improve, and the radiological changes resolved. Two years later he remains stable on maintenence oral steroids (dexamethasone 1 mg and 0-5 mg on alternate days) with no recurrence of pneumocystis pneumonia.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.