Tuberculin skin testing and QuantiFERON™-TB Gold Plus positivity among household contacts in Vietnam.

SETTING: TB infection (TBI) is diagnosed using the technique-dependent tuberculin skin test (TST) or costly, more accurate interferon-gamma release assays. The TST (⩾10 mm) threshold was indicated by previous research among household contacts in Vietnam, but routine implementation with a different tuberculin reagent showed unexpectedly low TST positivity. OBJECTIVE: TST (⩾5 mm and ⩾10 mm) results were compared to QuantiFERON™-TB Gold Plus (QFT) results in household contacts during community campaigns in 2020 and 2021. DESIGN: This was a cross-sectional multi-center implementation study. RESULTS: Among 1,330 household contacts in 2020, we found a TBI prevalence of 38.6% (QFT), similar to TST ⩾5 mm (37.4%) and higher than TST ⩾10 mm (13.1%). QFT+/TST+ was higher for TST ⩾5 mm (20.7%) than TST ⩾10 mm (9.4%). QFT was not discordant with TST ⩾5 mm (McNemar's test = 0.6, P = 0.5) but was discordant with TST ⩾10 mm (McNemar's test = 263.9, P < 0.01). Older age and Southern region increased odds for positive TST ⩾5 mm and QFT with weaker associations for TST ⩾10 mm. Agreement and discordance were similar in 2021 for 1,158 household contacts. CONCLUSION: Tuberculin reagents affect TST positivity rates. High TB burden countries should monitor reliability of TBI diagnosis, including tuberculin potency, cold chain, and TST technique to optimize eligibility for TB preventive treatment.

CONTEXTE: L'infection tuberculeuse (TBI) est diagnostiquée à l'aide du test cutané à la tuberculine (TST), qui dépend de la technique, ou de tests de libération de l'interféron-gamma, coûteux et plus précis. Des recherches antérieures ont indiqué que le TST (⩾10 mm) est généralement utilisé pour diagnostiquer la TB parmi les contacts familiaux au Vietnam ; la mise en œuvre de routine avec un réactif de tuberculine différent a montré une faible positivité inattendue du TST. OBJECTIF: Les résultats du TST (⩾5 mm et ⩾10 mm) ont été comparés aux résultats de QuantiFERON™-TB Gold Plus (QFT) chez les contacts familiaux au cours des campagnes communautaires de 2020 et 2021. MÉTHODE: Il s'agissait d'une étude transversale multicentrique de mise en œuvre. RÉSULTATS: Parmi 1 330 contacts familiaux en 2020, nous avons trouvé une prévalence de TBI de 38,6% (QFT), similaire au TST ⩾5 mm (37,4%) et plus élevée que le TST ⩾10 mm (13,1%). Le QFT+/TST+ était plus élevé pour le TST ⩾5 mm (20,7%) que pour le TST ⩾10 mm (9,4%). Le QFT n'était pas discordant avec le TST ≥5 mm (test de McNemar = 0,6 ; P = 0,5) mais était discordant avec le TST ⩾10 mm (test de McNemar = 263,9 ; P < 0,01). L'âge avancé et la région méridionale augmentaient les probabilités d'un TST positif ⩾5 mm et d'un QFT, avec des associations plus faibles pour un TST ⩾10 mm. La concordance et la discordance étaient similaires en 2021 pour 1 158 contacts familiaux. CONCLUSION: Les réactifs de tuberculine affectent les taux de positivité des TST. Les pays à forte charge de TB doivent surveiller la fiabilité du diagnostic de TBI, y compris la puissance de la tuberculine, la chaîne du froid et la technique du TST afin d'optimiser l'éligibilité au traitement préventif de la TB.

Comparison of Two Tuberculosis Infection Tests in a South American Tertiary Hospital: STANDARD F TB-Feron FIA vs. QIAreachTM QuantiFERON-TB.

INTRODUCTION: Tuberculosis (TB) is one of the most prevalent respiratory diseases in the world. In 2020 there were at least 9.9 million new infections, with 1.5 million deaths. Approximately 10% of people infected with Mycobacterium tuberculosis develop the disease during the first 2 to 5 years after infection. In South America, the diagnosis of Latent Tuberculosis Infections (LTBI) continues to be performed through the Mantoux tuberculin skin test (TST). OBJECTIVE: The objective of our study was to compare the sensitivity of a new immunofluorescence IGRA test against a widely available IGRA kit on the market. MATERIAL AND METHOD: Close contact with infectious TB patients, HIV patients, or immunocompromised for another cause were recruited. Two interferon-gamma release assay (IGRA) diagnostic kits were used and compared with TST. RESULTS: 76 patients were recruited, 93.42% were Chilean nationality, and 98.68% of the patients did not have immunosuppression. The sensitivity of the new technique was 88.89%, and the specificity was 92.50% in the study population compared to the IGRA previously used. In the subgroup older than 36 years, the sensitivity was 95.65%, and the specificity was 89.47%. CONCLUSION: IGRA techniques are a new resource in clinical laboratories to make an accurate diagnosis of LTBI in the region of the Americas. In our population, the greatest benefit of this new IGRA would be observed in people over 36 years of age, where the sensitivity of the technique was like that of the currently available test.

Intradermal comparative cervical tuberculin test in the diagnosis of caprine tuberculosis.

Tuberculosis remains one of the most important infectious diseases with well-known zoonotic nature that affect humans, wildlife, and domestic animals, including goats. Nonetheless, no intradermal tuberculin test has been standardized for caprine diagnosis of tuberculosis. The present study investigated the intradermal comparative cervical tuberculin test (ICCTT) in the diagnosis of tuberculosis among 60 goats from farms with history of tuberculosis. The cutoff applied to goats was based on a study where goats had been experimentally infected with Mycobacterium bovis and Mycobacterium avium. Clinical examination, bacteriological culture, and histopathological staining were assessed to the diagnosis. Isolates compatible with mycobacteria were subjected for molecular diagnosis based on gyrB-restriction fragment length polymorphism (RFLP) analysis and PCR restriction-enzyme analysis (PRA) of hsp65 gene by BstEII and HaeIII, namely PRA-hsp65 assay. From all goats, 60% (n = 36/60), 3.3% (n = 2/60), and 36.7% (n = 22/60) showed positive, inconclusive, and negative reactions, respectively. Out of 36 goats with ICCTT positive, 75% (n = 27/36) had isolation of mycobacteria and were detected M. bovis by gyrB-RFLP. Molecular diagnosis and histopathological findings compatible with tuberculosis showed 86.1% (n = 31/36) concordance with the ICCTT. When compared ICCTT with M. bovis isolation, gyrB-RFLP, and histopathology, the better arithmetic means of sensitivity and specificity were 2.5 mm for ICCTT compared with M. bovis isolation and gyrB-RFLP, and 4.55 mm when compared with histopathology. Both receiver operating characteristic (ROC) curves presented statistical significance (P < 0.001). The identification of other mycobacteria, e.g., M. kansasii, M. flavescens, M. avium, M. florentinum, M. lentiflavum, M. simiae, and Corynebacterium pseudotuberculosis, not influenced positive results in ICCTT. The concordance between bacteriological, histopathological, and molecular identification with ICCTT findings indicate that the tuberculin test may be used as a valuable tool for diagnosis of caprine tuberculosis and reinforce the importance of association of methods to diagnostic of the disease from animal origin.

Clinical outcome and diagnostic methods of atypical mycobacteriosis due to Mycobacterium avium ssp. hominissuis in a group of captive lowland tapirs (Tapirus terrestris).

Tapirs seem particularly susceptible to mycobacterial infections, especially to tuberculosis caused by M. tuberculosis or M. bovis. In this case series, we report an infection with the non-tuberculous mycobacteria (NTM) species M. avium ssp. hominissuis (MAH) in a group of four (2.2) captive lowland tapirs (Tapirus terrestris). Two female tapirs showed mild respiratory signs such as coughing and mucous sputum production for several years, one juvenile male tapir had to be euthanized due to severe dyspnoea, and the adult male only showed mild respiratory signs in 2010. Post-mortem histopathology of the euthanized animal revealed a chronic bronchopneumonia, and MAH was detected via culture. Subsequently, the three remaining tapirs were tested further: serologically, the tapirs had high antibody titres against M. avium, but they showed no reaction in the comparative skin test (TST). At several time points, the animals were tested for the presence of mycobacteria in different sample matrices including sputum samples, pooled faecal samples as well as swabs from the tapir enclosure to identify potential environmental niches of the pathogen. Moreover, animals were directly sampled using nasal swabs, endoscopic broncho-alveolar (BAL) and gastric lavages. MAH was detected by culture in the sputum samples, in the BAL of the breeding pair, as well as in the swimming pool water and walls, and in swabs taken from the tapir's sleeping beds. We conclude that the TST is not a useful diagnostic tool to detect MAC infections in tapirs, whereas antibody ELISA and culture from BAL appear more sensitive.

Incidence of Latent Tuberculosis Infection in a study of household contacts treated in a General Hospital of the City of Buenos Aires

Introduction: The study of household contacts of patients with tuberculosis (TB) is an essential strategy for the early diagnosis of latent tuberculosis infection (LTBI) and for the establishment of the corresponding treatment for the purpose of reducing TB prevalence in the population. Objective: To know the incidence of LTBI in household contacts and the degree of compliance with control studies and chemoprophylaxis (ChP). Materials and Methods: We carried out a retrospective analysis of > 15-year-old household contacts of patients with TB treated in the Hospital General de Agudos Parmenio Piñero between January 2016 and February 2018. Chest x-ray and tuberculin skin test (PPD, Purified Protein Derivative) were requested, considering ≥ 10 mm as a positive cut-off point. The tuberculin skin test was repeated after 3 months in subjects with negative results. ≥ 5 mm was also considered as PPD+ when analyzing the data. The cases in which patients followed > 80% of the indicated regime were considered as compliant with ChP: 3 months of isoniazid in primary ChP and 6 months in secondary ChP. Results: 4 (1.2%) of the 344 admitted contacts were diagnosed with TB through chest x-rays with pathological images. These 4 contacts with TB were excluded from the study. Within the remaining 340 subjects, with a mean age of 35 ± 16 years, there were 154 (45%) males, 180 (52%) Argentinians and 144 (43%) Bolivians. Of the 193 (57%) subjects who complied with the performance of the basal PPD test, 38 (20%) showed PPD ≥ 10 mm and 89 (46%) ≥ 5 mm. Women were more compliant than men with PPD testing: 122 out of 186 (55%) vs. 71 out of 154 (45%); p = 0.005. There was no significant difference as regards age and nationality. Only 33 (21%) patients complied with the performance of the second PPD test, without any conversions for the 10 mm cut-off point, and with 3 conversions considering ≥ 5 mm as PPD+. Primary ChP was indicated to 55 patients, and secondary ChP to 38 patients. The compliance rate was 75% and 39%, respectively, without a significant association with age, gender or nationality. No adverse event associated with isoniazid was reported. Conclusion: We found 20% LTBI within the population under study considering ≥ 10 mm as PPD+; 46% was found with ≥ 5 mm PPD. There was a low level of compliance with the performance of the PPD test (though it was higher in women) and of secondary ChP.

La prueba tuberculínica y el trabajo invisible de enfermería / The tuberculin test and the invisible nursing work

Introducción: La Tuberculosis es la segunda causa mundial de mortalidad, después del SIDA, causada por un agente infeccioso. Objetivos: teorizar la administración y lectura de la reacción Tuberculiníca como práctica enfermera, liberándola de concepciones positivistas y patriarcales que obturan el desarrollo del conocimiento enfermero. Métodos: revisión bibliográfica en las bases de datos especializadas (CUIDEN, REDALYC y LILACS) y análisis Meta teórico. Conclusiones: analizando críticamente la prueba Tuberculiníca se puede recuperar la práctica enfermera como fuente de teoría para incrementar el conocimiento enfermero, redundando en beneficio de los pacientes y el sistema de salud(AU)

Introduction: tuberculosis is worldwide the second cause of mortality caused by an infectious agent, after AIDS. Objectives: to theorize about the administration and reading of the tuberculin reactions as a nursing practice, freeing it from positivist and patriarchal conceptions that obdurate the development of the nursing knowledge. Methods: bibliographic review in the specialized databases (CUIDEN, REDALYC y LILACS) and meta-theoretical analysis. Conclusions: critically analyzing the tuberculin test, the nursing practice can be recovered as a source of theory to increase nursing knowledge, resulting in the benefit of patients and the health system(AU)

Screening and treatment of latent tuberculosis infection among HIV-infected patients in resource-rich settings.

Current international guidelines recommend screening and treatment of latent tuberculosis (TB) infection in HIV-infected patients in all settings. The main factors affecting the risk of TB in HIV-infected patients include the level of immunosuppression, coverage of antiretroviral therapy and local TB burden. In resource-rich settings where antiretroviral therapy is more accessible and HIV-infected patients are expected to be diagnosed at an earlier stage, local TB burden remains a key factor on their risk of TB. This article reviewed the epidemiology of latent TB infection among the adult HIV-infected patients, and the use and benefit of screening and treatment of latent TB infection in resource-rich settings in the past decade. While such practice should be continued in countries with medium or high TB burden, targeted screening and treatment only for HIV-infected patients with additional risk factors for TB might be a more practical option in resource-rich countries with low TB burden.

Management of Infants and Children who are Contacts of Contagious Tuberculous Patients.

Contact investigation and management form the key for tuberculosis (TB) control in countries with a low tuberculosis incidence. Oman, with a low TB incidence, has implemented contact investigation and management as one important strategy to control TB. However there is a lack of clear guidelines for the investigation and treatment of contacts, especially with regard to children who are contacts of TB cases. The failure to manage children in contact with infectious TB cases indicates a missed opportunity to prevent TB disease in a population which is prone to progress rapidly to severe and complicated illness. This article attempts to provide a concise and practical approach for managing infants and children who are in contact with TB patients. Essential steps in a variety of possible scenarios are briefly discussed.