A low risk of nosocomial transmission of subclinical tuberculosis to neonates in a postpartum care center under COVID-19 control measures

We report the results of investigating and managing a tuberculosis (TB) exposure in apostpartum care center. Among the contacts exposed to a nursing assistant with subclinical TB,5 of 44 neonates (11.4%) had positive tuberculin skin tests (TSTs) at 3 months of age, and all theTST-positive neonates received the Bacille Calmette-Guérin vaccination. Seven of 28 healthcareworkers (25.0%) and 1 of 3 household contacts (33.3%) were positive in the initial or repeatedinterferon-gamma release assay. None of the contacts developed TB disease during the studyperiod. Annual TB examinations of healthcare personnel at a postpartum care center under theTuberculosis Prevention Act in South Korea enabled the early detection of subclinical TB, whichreduced the risk of transmission to neonates under strict coronavirus disease 2019 preventionmeasures.

Transmission of multidrug-resistant tuberculosis in Beijing, China: An epidemiological and genomic analysis

Background

Understanding multidrug-resistant tuberculosis (MDR-TB) transmission patterns is crucial for controlling the disease. We aimed to identify high-risk populations and geographic settings of MDR-TB transmission.

Methods

We conducted a population-based retrospective study of MDR-TB patients in Beijing from 2018 to 2020, and assessed MDR-TB recent transmission using whole-genome sequencing of isolates. Geospatial analysis was conducted with kernel density estimation. We combined TransPhylo software with epidemiological investigation data to construct transmission networks. Logistic regression analysis was utilized to identify risk factors for recent transmission.

Results

We included 241 MDR-TB patients, of which 146 (60.58%) were available for genomic analysis. Drug resistance prediction showed that resistance to fluoroquinolones (FQs) was as high as 39.74% among new cases. 36 (24.66%) of the 146 MDR strains were grouped into 12 genome clusters, suggesting recent transmission of MDR strains. 44.82% (13/29) of the clustered patients lived in the same residential community, adjacent residential community or the same street as other cases. The inferred transmission chain found a total of 6 transmission events in 3 clusters; of these, 4 transmission events occurred in residential areas and nearby public places. Logistic regression analysis revealed that being aged 25-34 years-old was a risk factor for recent transmission.

Conclusions

The recent transmission of MDR-TB in Beijing is severe, and residential areas are common sites of transmission; high levels of FQs drug resistance suggest that FQs should be used with caution unless resistance can be ruled out by laboratory testing.

The impact of Mycobacterium tuberculosis complex in the environment on one health approach

Tuberculosis caused by the Mycobacterium tuberculosis complex (MTBC) has become one of the leading causes of death in humans and animals. Current research suggests that the transmission of MTBC in the environment indirectly transmit to humans and animals with subsequent impact on their wellbeing. Therefore, it is of great significance to take One Health approach for understanding the role of MTBC in not only the interfaces of humans and animals, but also environment, including soil, water, pasture, air, and dust, etc., in response to the MTBC infection. In this review, we present the evidence of MTBC transmission from environment, as well as detection and control strategies in this interface, seeking to provide academic leads for the global goal of End Tuberculosis Strategy under multidisciplinary and multisectoral collaborations.

Association of N6-methyladenosine readers' genes variation and expression level with pulmonary tuberculosis

N6-Methyladenosine (m6A) is associated with many biological processes and the development of multiple diseases. The aim of this study was to analyze the association of m6A readers' genes variation, as well as their expression levels, with pulmonary tuberculosis (PTB). A total of 11 single-nucleotide polymorphisms (SNPs) in m6A readers' genes (i.e., YTHDF1 rs6122103, rs6011668, YTHDF2 rs602345, rs3738067, YTHDF3 rs7464, rs12549833, YTHDC1 rs3813832, rs17592288, rs2293596, and YTHDC2 rs6594732, and rs2416282) were genotyped by SNPscan™ technique in 457 patients with PTB and 466 normal controls. The m6A readers' genes expression levels in peripheral blood mononuclear cells (PBMCs) from 78 patients with PTB and 86 normal controls were detected by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). There was no significant association between all SNPs in YTHDF1, YTHDF2, YTHDF3, YTHDC1, and YTHDC2 genes and PTB susceptibility. The increased frequencies of YTHDF2 rs3738067 GG genotype and YTHDC1 rs3813832 CC genotype, C allele, were, respectively, found in PTB patients with hypoproteinemia and fever. YTHDC2 rs6594732 variant was significantly associated with drug-induced liver damage and sputum smear-positive, and the rs2416282 variant was significantly associated with fever in patients with PTB. Compared with controls, the YTHDF1, YTHDF2, YTHDF3, YTHDC1, and YTHDC2 mRNA levels were significantly decreased in PTB. Moreover, YTHDF1 level was negatively associated with erythrocyte sedimentation rate (ESR), and YTHDF3 and YTHDC1 levels were negatively related to alanine aminotransferase (ALT) in patients with PTB. Our results demonstrated that YTHDF1, YTHDF2, YTHDF3, YTHDC1, and YTHDC2 genes SNPs did not contribute to PTB susceptibility, while their decreased levels in patients with PTB suggested that these m6A readers might play significant roles in PTB.

The impact of the COVID-19 pandemic and associated suppression measures on the burden of tuberculosis in India

Background

Tuberculosis (TB) is a major cause of death globally. India carries the highest share of the global TB burden. The COVID-19 pandemic has severely impacted diagnosis of TB in India, yet there is limited data on how TB case reporting has changed since the pandemic began and which factors determine differences in case notification.

Methods

We utilized publicly available data on TB case reporting through the Indian Central TB Division from January 2017 through April of 2021 (prior to the first COVID-19 related lockdown). Using a Poisson model, we estimated seasonal and yearly patterns in TB case notification in India from January 2017 through February 2020 and extended this estimate as the counterfactual expected TB cases notified from March 2020 through April 2021. We characterized the differences in case notification observed and those expected in the absence of the pandemic by State and Territory. We then performed a linear regression to examine the relationship between the logit ratio of reported TB to counterfactual cases and mask use, mobility, daily hospitalizations/100,000 population, and public/total TB case reporting.

Results

We found 1,320,203 expected cases of TB (95% uncertainty interval (UI) 1,309,612 to 1,330,693) were not reported during the period from March 2020 through April 2021. This represents a 63.3% difference (95% UI 62.8 to 63.8) in reporting. We found that mobility data and average hospital admissions per month per population were correlated with differences in TB case notification, compared to the counterfactual in the absence of the pandemic (p > 0.001).

Conclusion

There was a large difference between reported TB cases in India and those expected in the absence of the pandemic. This information can help inform the Indian TB program as they consider interventions to accelerate case finding and notification once the pandemic related TB service disruptions improve. Mobility data and hospital admissions are surrogate measures that correlate with a greater difference in reported/expected TB cases and may correlate with a disruption in TB diagnostic services. However, further research is needed to clarify this association and identify other key contributors to gaps in TB case notifications in India.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07078-y.

Prevention of Mycobacterium tuberculosis Transmission in Health Care Settings

Patients with tuberculosis (TB) pose a risk to other patients and health care workers, and outbreaks in health care settings occur when appropriate infection control measures are not used. This article discusses strategies to prevent transmission of Mycobacterium tuberculosis within health care settings. All health care facilities should have an operational TB infection control plan that emphasizes the use of a hierarchy of controls (administrative, environmental, and personal respiratory protection). Resources available to clinicians who work in the prevention and investigation of nosocomial transmission of M tuberculosis also are discussed.

Expiratory aerosol particle escape from surgical masks due to imperfect sealing

Wearing surgical masks or other similar face coverings can reduce the emission of expiratory particles produced via breathing, talking, coughing, or sneezing. Although it is well established that some fraction of the expiratory airflow leaks around the edges of the mask, it is unclear how these leakage airflows affect the overall efficiency with which masks block emission of expiratory aerosol particles. Here, we show experimentally that the aerosol particle concentrations in the leakage airflows around a surgical mask are reduced compared to no mask wearing, with the magnitude of reduction dependent on the direction of escape (out the top, the sides, or the bottom). Because the actual leakage flowrate in each direction is difficult to measure, we use a Monte Carlo approach to estimate flow-corrected particle emission rates for particles having diameters in the range 0.5-20 μm. in all orientations. From these, we derive a flow-weighted overall number-based particle removal efficiency for the mask. The overall mask efficiency, accounting both for air that passes through the mask and for leakage flows, is reduced compared to the through-mask filtration efficiency, from 93 to 70% for talking, but from only 94-90% for coughing. These results demonstrate that leakage flows due to imperfect sealing do decrease mask efficiencies for reducing emission of expiratory particles, but even with such leakage surgical masks provide substantial control.

Context matters: Examining the factors impacting the implementation of tuberculosis infection prevention and control guidelines in health settings in seven high tuberculosis burden countries

BACKGROUND

Healthcare workers (HCWs) in high tuberculosis (TB) burden countries are at increased risk of TB infection due to increased exposures to TB patients and inadequate implementation of TB infection prevention and control (TB IPC) measures in health settings. While various guidelines on TB IPC exist, there is little understanding of the content of these guidelines, whether they are relevant to the context and are being appropriately implemented in low-and middle-income high TB burden countries. This study aimed to critically examine the implementation of TB IPC guidelines, along with factors impacting TB IPC implementation in health settings in seven high TB burden countries.

METHODS

The WHO 2009 and national level TB IPC guidelines and the published literature from seven TB high burden countries were reviewed and relevant information extracted. Eleven key-stakeholders from the case study countries were interviewed to elucidate further facilitators and barriers impacting TB IPC guidelines implementation.

RESULTS

Our study identified that all the study countries adopted the WHO 2009 guidelines with no or minimal modifications for the local context. Therefore, the subsequent translation of the TB IPC recommendations into practice has been limited and impaired in some settings. Poor infrastructure, inadequate space for isolation, lack of TB IPC training, limited supply of personal protective equipment, the discomfort of using N95 respirators, and a high number of TB patients were some of the factors impacting the implementation of TB IPC guidelines.

CONCLUSION

The implementation of TB IPC guidelines in all seven countries was limited. It was affected by the diverse context where each of the countries and each of the facilities had a different health infrastructure and TB disease burdens. The findings warrant re-assessment of the current context prevailing in these high TB burden countries and subsequent revisions of national guidelines based to account for local context and evidence.