The impact of HIV infection on tuberculosis transmission in a country with low tuberculosis incidence: a national retrospective study using molecular epidemiology.

Background: HIV is known to increase the likelihood of reactivation of latent tuberculosis to active TB disease; however, its impact on tuberculosis infectiousness and consequent transmission is unclear, particularly in low-incidence settings.

Methods: National surveillance data from England, Wales and Northern Ireland on tuberculosis cases in adults from 2010 to 2014, strain typed using 24-locus mycobacterial-interspersed-repetitive-units-variable-number-tandem-repeats was used retrospectively to identify clusters of tuberculosis cases, subdivided into 'first' and 'subsequent' cases. Firstly, we used zero-inflated Poisson regression models to examine the association between HIV status and the number of subsequent clustered cases (a surrogate for tuberculosis infectiousness) in a strain type cluster.

A model of tuberculosis clustering in low incidence countries reveals more transmission in the United Kingdom than the Netherlands between 2010 and 2015.

Tuberculosis (TB) remains a public health threat in low TB incidence countries, through a combination of reactivated disease and onward transmission. Using surveillance data from the United Kingdom (UK) and the Netherlands (NL), we demonstrate a simple and predictable relationship between the probability of observing a cluster and its size (the number of cases with a single genotype). We demonstrate that the full range of observed cluster sizes can be described using a modified branching process model with the individual reproduction number following a Poisson lognormal distribution.

Trends and risk factors for death and excess all-cause mortality among notified tuberculosis patients in the UK: an analysis of surveillance data.

Introduction: In the UK, several hundred patients notified with tuberculosis (TB) die every year. The aim of this article is to describe trends in deaths among notified TB patients, explore risk factors associated with death and compare all-cause mortality in TB patients with age-specific mortality rates in the general UK population.

Methods: We used 2001-2014 data from UK national TB surveillance to explore trends and risk factors for death, and population mortality data to compare age-specific death rates among notified TB patients with annual death rates in the UK general population.

Effectiveness of pre-entry active tuberculosis and post-entry latent tuberculosis screening in new entrants to the UK: a retrospective, population-based cohort study.

Background: Evaluating interventions that might lead to a reduction in tuberculosis in high-income countries with a low incidence of the disease is key to accelerate progress towards its elimination. In such countries, migrants are known to contribute a large proportion of tuberculosis cases to the burden. We assessed the effectiveness of screening for active tuberculosis before entry to the UK and for latent tuberculosis infection (LTBI) post-entry for reduction of tuberculosis in new-entrant migrants to the UK.

Fluoroquinolones and isoniazid-resistant tuberculosis: implications for the 2018 WHO guidance.

Introduction: 2018 World Health Organization (WHO) guidelines for the treatment of isoniazid (H)-resistant (Hr) tuberculosis recommend a four-drug regimen: rifampicin (R), ethambutol (E), pyrazinamide (Z) and levofloxacin (Lfx), with or without H ([H]RZE-Lfx). This is used once Hr is known, such that patients complete 6 months of Lfx (≥6[H]RZE-6Lfx). This cohort study assessed the impact of fluoroquinolones (Fq) on treatment effectiveness, accounting for Hr mutations and degree of phenotypic resistance.

Exploring the effects of BCG vaccination in patients diagnosed with tuberculosis: Observational study using the Enhanced Tuberculosis Surveillance system.

Background: Bacillus Calmette-Guérin (BCG) is one of the most widely-used vaccines worldwide. BCG primarily reduces the progression from infection to disease, however there is evidence that BCG may provide additional benefits. We aimed to investigate whether there is evidence in routinely-collected surveillance data that BCG vaccination impacts outcomes for tuberculosis (TB) cases in England.

Creating a web-based electronic tool to aid tuberculosis (TB) cluster investigation: data integration in TB surveillance activities in the United Kingdom, 2013 to 2016.

Molecular technology to identify relatedness between complex isolates, representative of possible tuberculosis (TB) transmission between individuals, continues to evolve. At the same time, tools to utilise this information for public health action to improve TB control should also be implemented. Public Health England developed the Strain Typing Module (STM) as an integral part of the web-based surveillance system used in the United Kingdom following the roll-out of prospective 24 loci mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) strain typing.

The Changing Landscape of Childhood Tuberculosis in the United Kingdom: A Retrospective Cohort (2000-2015).

Background: The epidemiology of tuberculosis (TB) is changing in the United Kingdom and globally. Childhood TB is a key indicator of recent transmission and provides a marker of wider TB control. We describe the recent epidemiology of childhood TB in the United Kingdom, how this compares to TB in adults, and document changes with time.

Trends in, and factors associated with, HIV infection amongst tuberculosis patients in the era of anti-retroviral therapy: a retrospective study in England, Wales and Northern Ireland.

Background: HIV increases the progression of latent tuberculosis (TB) infection to active disease and contributed to increased TB in the UK until 2004. We describe temporal trends in HIV infection amongst patients with TB and identify factors associated with HIV infection.

Methods: We used national surveillance data of all TB cases reported in England, Wales and Northern Ireland from 2000 to 2014 and determined HIV status through record linkage to national HIV surveillance.

Understanding Tuberculosis Transmission in the United Kingdom: Findings From 6 Years of Mycobacterial Interspersed Repetitive Unit-Variable Number Tandem Repeats Strain Typing, 2010-2015.

Genotyping provides the opportunity to better understand tuberculosis (TB) transmission. We utilized strain typing data to assess trends in the proportion of clustering and identify the characteristics of individuals and clusters associated with recent United Kingdom (UK) transmission. In this retrospective cohort analysis, we included all culture-confirmed strain-typed TB notifications from the UK between 2010 and 2015 to estimate the proportion of patients that clustered over time.

The use of whole-genome sequencing in cluster investigation of a multidrug-resistant tuberculosis outbreak.

We used whole-genome sequencing (WGS) to delineate transmission networks and investigate the benefits of WGS during cluster investigation.We included clustered cases of multidrug-resistant (MDR) tuberculosis (TB)/extensively drug-resistant (XDR) TB linked by mycobacterial interspersed repetitive unit variable tandem repeat (MIRU-VNTR) strain typing or epidemiological information in the national cluster B1006, notified between 2007 and 2013 in the UK. We excluded from further investigation cases whose isolates differed by greater than 12 single nucleotide polymorphisms (SNPs).

Reduction in tuberculosis incidence in the UK from 2011 to 2015: a population-based study.

Background: Following nearly two decades of increasing tuberculosis in the UK, TB incidence decreased by 32% from 2011 to 2015. Explaining this reduction is crucial to informing ongoing TB control efforts.

Methods: We stratified TB cases notified in the UK and TB cases averted in the UK through pre-entry screening (PES) between 2011 and 2015 by country of birth and time since arrival.

Acquired Resistance to Antituberculosis Drugs in England, Wales, and Northern Ireland, 2000-2015.

Among tuberculosis (TB) patients, acquired resistance to anti-TB drugs represents a failure in the treatment pathway. To improve diagnosis and care for patients with drug-resistant TB, we examined the epidemiology and risk factors associated with acquired drug resistance during 2000-2015 among TB patients in England, Wales, and Northern Ireland. We found acquired resistance in 0.

Injecting drug use predicts active tuberculosis in a national cohort of people living with HIV.

Objectives: Tuberculosis (TB) is common in people living with HIV, leading to worse clinical outcomes including increased mortality. We investigated risk factors for developing TB following HIV diagnosis.

Design: Adults aged at least 15 years first presenting to health services for HIV care in England, Wales or Northern Ireland from 2000 to 2014 were identified from national HIV surveillance data and linked to TB surveillance data.

Recent household transmission of tuberculosis in England, 2010-2012: retrospective national cohort study combining epidemiological and molecular strain typing data.

Background: We estimate the proportion of tuberculosis (TB) in England due to recent household transmission, identify factors associated with being a household transmitter, and investigate the impact that identification of a case has on time to treatment of subsequent cases.

Methods: TB cases notified between 2010 and 2012 in England in the same household as another case were identified; 24 locus MIRU-VNTR strain typing (ST) was used to identify household cases with likely recent transmission. Treatment delay in index and subsequent cases was compared.

Twenty years and counting: epidemiology of an outbreak of isoniazid-resistant tuberculosis in England and Wales, 1995 to 2014.

An outbreak of isoniazid-resistant tuberculosis first identified in London has now been ongoing for 20 years, making it the largest drug-resistant outbreak of tuberculosis documented to date worldwide. We identified culture-confirmed cases with indistinguishable molecular strain types and extracted demographic, clinical, microbiological and social risk factor data from surveillance systems. We summarised changes over time and used kernel-density estimation and k-function analysis to assess geographic clustering.

Epidemiology of Mycobacterium bovis Disease in Humans in England, Wales, and Northern Ireland, 2002-2014.

Despite control efforts, Mycobacterium bovis incidence among cattle remains high in parts of England, Wales, and Northern Ireland, attracting political and public health interest in potential spread from animals to humans. To determine incidence among humans and to identify associated factors, we conducted a retrospective cohort analysis of human M. bovis cases in England, Wales, and Northern Ireland during 2002-2014.

Insidious Risk of Severe Mycobacterium chimaera Infection in Cardiac Surgery Patients.

Background: An urgent UK investigation was launched to assess risk of invasive Mycobacterium chimaera infection in cardiothoracic surgery and a possible association with cardiopulmonary bypass heater-cooler units following alerts in Switzerland and The Netherlands.

Methods: Parallel investigations were pursued: (1) identification of cardiopulmonary bypass-associated M. chimaera infection through national laboratory and hospital admissions data linkage; (2) cohort study to assess patient risk; (3) microbiological and aerobiological investigations of heater-coolers in situ and under controlled laboratory conditions; and (4) whole-genome sequencing of clinical and environmental isolates.

Tuberculosis in migrants moving from high-incidence to low-incidence countries: a population-based cohort study of 519 955 migrants screened before entry to England, Wales, and Northern Ireland.

Background: Tuberculosis elimination in countries with a low incidence of the disease necessitates multiple interventions, including innovations in migrant screening. We examined a cohort of migrants screened for tuberculosis before entry to England, Wales, and Northern Ireland and tracked the development of disease in this group after arrival.

Methods: As part of a pilot pre-entry screening programme for tuberculosis in 15 countries with a high incidence of the disease, the International Organization for Migration screened all applicants for UK visas aged 11 years or older who intended to stay for more than 6 months.

Recent TB transmission, clustering and predictors of large clusters in London, 2010-2012: results from first 3 years of universal MIRU-VNTR strain typing.

Background: The incidence of TB has doubled in the last 20 years in London. A better understanding of risk groups for recent transmission is required to effectively target interventions. We investigated the molecular epidemiological characteristics of TB cases to estimate the proportion of cases due to recent transmission, and identify predictors for belonging to a cluster.

Pulmonary Mycobacterium avium-intracellulare is the main driver of the rise in non-tuberculous mycobacteria incidence in England, Wales and Northern Ireland, 2007-2012.

Background: The incidence of non-tuberculous mycobacteria (NTM) isolation from humans is increasing worldwide. In England, Wales and Northern Ireland (EW&NI) the reported rate of NTM more than doubled between 1996 and 2006. Although NTM infection has traditionally been associated with immunosuppressed individuals or those with severe underlying lung damage, pulmonary NTM infection and disease may occur in people with no overt immune deficiency.

Towards better guidance on caseload thresholds to promote positive tuberculosis treatment outcomes: a cohort study.

Background: In low-incidence countries, clinical experience of tuberculosis is becoming more limited, with potential consequences for patient outcomes. In 2007, the Department of Health released a guidance 'toolkit' recommending that tuberculosis patients in England should not be solely managed by clinicians who see fewer than 10 cases per year. This caseload threshold was established to try to improve treatment outcomes and reduce transmission, but was not evidence based.

TB in healthcare workers in the UK: a cohort analysis 2009-2013.

Objectives: To describe the burden of TB in healthcare workers (HCWs) in the UK and determine whether HCWs are at increased risk of TB due to occupational exposure.

Methods: Retrospective cohort analysis of national UK TB surveillance and genotyping data between 2009 and 2013. The rate of TB in HCWs compared with non-HCWs to calculate incidence rate ratios stratified by country of birth.

Assessment of Mycobacterium tuberculosis transmission in Oxfordshire, UK, 2007-12, with whole pathogen genome sequences: an observational study.

Background: Patients born outside the UK have contributed to a 20% rise in the UK's tuberculosis incidence since 2000, but their effect on domestic transmission is not known. Here we use whole-genome sequencing to investigate the epidemiology of tuberculosis transmission in an unselected population over 6 years.

Methods: We identified all residents with Oxfordshire postcodes with a Mycobacterium tuberculosis culture or a clinical diagnosis of tuberculosis between Jan 1, 2007, and Dec 31, 2012, using local databases and checking against the national Enhanced Tuberculosis Surveillance database.

Factors affecting immunogenicity of BCG in infants, a study in Malawi, The Gambia and the UK.

Background: BCG immunogenicity in infants differs between populations and these differences have been attributed to various factors. In this study, the influence of geographical location, season of birth, timing of vaccination, micronutrient status (zinc) and inflammatory status (C-reactive protein, CRP) were assessed.

Methods: Immunogenicity was assessed by cytokine signature in culture supernatants from diluted whole blood samples stimulated with M.