A pulmonary tuberculosis outbreak in a long-term care facility

Determinants of latent tuberculosis infection and treatment interruption in long-term care facilities: A retrospective cohort study in Taiwan

BACKGROUND/PURPOSE

Latent tuberculosis infection (LTBI) treatment is challenging in long-term care facilities (LTCFs) residents due to the occurrence of medical complexities. However, factors associated with treatment interruption have not been extensively studied. This retrospective cohort study aimed to determine LTBI-associated factors and treatment interruption in LTCF residents and employees in Taiwan.

METHODS

From May 2017 through September 2020, the residents and employees of 20 LTCFs in Taipei, Taiwan, were screened for LTBI by using QuantiFERON-TB Gold In-Tube test. The LTBI individuals underwent directly observed preventive therapy (DOPT), including regimens of 9-month daily isoniazid (9H) and 3-month weekly isoniazid plus rifapentine (3HP). All the LTBI cases were followed up till treatment completion, death, or treatment interruption.

RESULTS

Among 2207 LTCF subjects, 16.8% had LTBI. After controlling for other covariates, residents of public facilities had a significantly higher LTBI prevalence than those of private facilities (adjusted odds ratio [AOR] = 1.43; 95% confidence interval [CI]: 1.08-1.88). Among 264 LTBI cases receiving preventive therapy, 52 (19.7%) had treatment interruption. LTBI cases receiving 3HP were less likely to have treatment interruption than those receiving 9H (AOR = 0.22; 95% CI: 0.07-0.71).

CONCLUSIONS

LTCF residents, particular those living in public facilities, had a high LTBI prevalence. 3HP with DOPT is considered the priority regimen for preventive therapy among LTBI cases in LTCFs.

A systematic review on the causes of the transmission and control measures of outbreaks in long-term care facilities: Back to basics of infection control

BACKGROUND

The unique characteristics of long-term care facilities (LTCFs) including host factors and living conditions contribute to the spread of contagious pathogens. Control measures are essential to interrupt the transmission and to manage outbreaks effectively.

AIM

The aim of this systematic review was to verify the causes and problems contributing to transmission and to identify control measures during outbreaks in LTCFs.

METHODS

Four electronic databases were searched for articles published from 2007 to 2018. Articles written in English reporting outbreaks in LTCFs were included. The quality of the studies was assessed using the risk-of-bias assessment tool for nonrandomized studies.

FINDINGS

A total of 37 studies were included in the qualitative synthesis. The most commonly reported single pathogen was influenza virus, followed by group A streptococcus (GAS). Of the studies that identified the cause, about half of them noted outbreaks transmitted via person-to-person. Suboptimal infection control practice including inadequate decontamination and poor hand hygiene was the most frequently raised issue propagating transmission. Especially, lapses in specific care procedures were linked with outbreaks of GAS and hepatitis B and C viruses. About 60% of the included studies reported affected cases among staff, but only a few studies implemented work restriction during outbreaks.

CONCLUSIONS

This review indicates that the violation of basic infection control practice could be a major role in introducing and facilitating the spread of contagious diseases in LTCFs. It shows the need to promote compliance with basic practices of infection control to prevent outbreaks in LTCFs.

An office building outbreak: the changing epidemiology of tuberculosis in Shenzhen, China

Tuberculosis (TB) is generally considered a disease that principally afflicts the low-income segments of a population. In the Nanshan District of Shenzhen, China, with the economic transformation and a new Headquarters Economy (HE) emerging, there are now more cases in office workers than in manufacturing workers. To illustrate this trend, we describe a small TB outbreak in an office building located in the centre of the rapidly growing HE district. Two active pulmonary tuberculosis cases were found in workers who shared an office, and whole genome sequencing showed that the genetic distance between the strains of the two cases was just one single nucleotide polymorphism, consistent with intra-office transmission. Investigation of 30 other workers in the same or adjacent offices with interviews, interferon-gamma release assays (IGRAs) and chest X-rays, identified one new TB case and latent tuberculosis infection (LTBI) in 40.0% (12/30) of the contacts. The offices were under-ventilated. None of the IGRA positive, asymptomatic contacts agreed to receive treatment for LTBI, presumably due to TB stigma, and over the next 2 years 69.0% (20/29) of the contacts were lost to follow-up. Treatment for LTBI and stigma of TB remain challenges here. Office workers in the HE of rapidly economic developing areas should be targeted with increased vigilance by TB control programmes.

Ambulatory independence is associated with higher incidence of latent tuberculosis infection in long-term care facilities in Taiwan

BACKGROUND/PURPOSE

Tuberculosis (TB) in the elderly population remains a major challenge in areas with intermediate disease burden like Taiwan. Despite the increasing burden and high risks of TB in the elderly population, particularly those living in long-term care facilities (LTCFs), diagnostic testing for latent tuberculosis infection (LTBI) has not been carefully evaluated in this group. This study aimed to investigate the prevalence and predictors of LTBI in older adults living in LTCFs.

METHODS

Older adults living in seven LTCFs in Taiwan were prospectively enrolled between January and July 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-tube was used to determine presence of LTBI. Predictors for LTBI were analyzed.

RESULTS

A total of 258 participants were enrolled, including 240 older residents (mean age, 81.6 years; male, 51.2%) and 18 employees (mean age, 64.8 years; male, 22.2%). The proportion of independent status in ambulation assessments significantly declined with aging (p < 0.001). The IGRA-positivity rate in LTCFs was 31.4% (81/258), which consisted of 73 (30.4%) residents and 8 (44.4%) employees. The IGRA results were different with respect to the ambulation status (p = 0.052). In the multivariate logistic regression analysis, the only independent predictor of LTBI among older adults in LTCFs was independent ambulation (odds ratio, 2.16; 95% confidence interval, 1.09-4.28; p = 0.027).

CONCLUSIONS

There was a high prevalence of LTBI among older adults in LTCFs in Taiwan. Independent ambulation was the only independent predictor of LTBI.

Implications of a school outbreak of multidrug-resistant tuberculosis in Northern China

In this study, we identified a multidrug-resistant tuberculosis (MDR-TB) outbreak in a high school in northern China. The aim of this work was to describe TB transmission, drug resistance and treatment outcomes for this patient cluster. In January 2017, pulmonary TB was identified in a 17-year-old boy in northern China. Subsequently, a total of 11 TB cases were identified during 6-month follow-up of attendees of the same school. Of five students with latent TB infection (LTBI) receiving isoniazid preventive therapy (IPT), two pulmonary TB cases (40.0%) emerged in March and April, for an active case rate not significantly different from that of the non-IPT group (4/16, 25.0%, P = 0.598). All TB patients were first treated with a standardised first-line treatment regimen administered by the local TB hospital, with 11 of 12 active TB patients exhibiting poor treatment outcomes. Further data demonstrated that all nine patient isolates collected during this outbreak were MDR-TB and shared a common genotypic profile. In conclusion, our data demonstrate that diagnostic delay for the index MDR-TB case of this outbreak played a primary role in transmission of MDR-TB infection within a school setting. Importantly, IPT failed to prevent progression of MDR-TB from LTBI to active TB.

B cell responses in older adults with latent tuberculosis: Considerations for vaccine development

Reactivation of latent tuberculosis (LTBI) is more common among the aging population and may contribute to increased transmission in long-term health care facilities. Difficulties in detecting LTBI due to potential blunting of the tuberculin skin test (TST), and the lowered ability of the elderly to tolerate the course of antibiotics, underscore the need for an effective vaccine. Immuno-senescence reduces the capacity of vaccines to induce sufficient levels of protective immunity against many pathogens, further increasing the susceptibility of the elderly to infectious diseases. We sought to evaluate the response of B cells to Mycobacterium tuberculosis (Mtb) in residents of long-term care facilities to determine the feasibility of using a vaccine to control infection and transmission from reactivated LTBI. Our results demonstrate that although B cell responses were higher in subjects with LTBI, Mtb antigens could stimulate B cell activation and differentiation in vitro in TST negative subjects. B cells from elderly subjects expressed high basal levels of Toll-like receptor (TLR)2 and TLR4 and responded strongly to Mtb ligands with some activation pathways dependent on TLR2. B cells derived from blood, tonsil and spleen from younger subjects responded similarly and to the same magnitude. These results suggest that B cell responses are robust in the elderly and modifications to a TB vaccine, such as TLR2 ligand-based adjuvants, may help increase immune responses to a protective level.