Natural disasters and nontuberculous mycobacteria: a recipe for increased disease?

Current Trends in Identification and Susceptibility Testing of Mycobacteria

While Mycobacterium species cause various infections, extrapulmonary tuberculosis (EPTB) and nontuberculous mycobacterial (NTM) infections were overlooked in the past. However, the incidence rates of these infections have increased over time. Similarly, there are limited testing modalities for diagnosing NTM and EPTB. In this review, we described the contemporary testing methods and associated challenges and benefits for NTM and EPTB.

The effect of the great Kermanshah earthquake on the tuberculosis infection trend: interrupted time series analysis

OBJECTIVES

Tuberculosis (TB) presents a substantial danger to populations experiencing crises like earthquakes. This study aims to explore the effect of the Kermanshah earthquake on the trend of TB.

METHODS

This cross-sectional study examined tuberculosis data from 2009 to 2020, using monthly diagnoses. Data was collected from the TB research office and registration system. The study employed interrupted time series (ITS) analysis to assess both the immediate and long-term impacts of the earthquake on TB cases.

RESULTS

In Sarpol-e Zahab, TB cases initially surged after the earthquake, indicating an immediate effect, but then significantly declined compared to pre-earthquake levels, reflecting an effect over time (β0 = 1.39, β1=-0.004, β2 = 0.11 and β3=-0.01, P = 0.001 and Post-intervention linear trend= -0.015, P < 0.001). In Ghasr-e Shirin, the average number of TB cases prior to the earthquake was estimated at 0.58 cases, with a significant monthly decrease of 0.005 cases leading up to the earthquake (P = 0.001). There was no significant immediate change in TB cases during the first month after the earthquake (β2 = 0.008, P = 0.680). Post-earthquake, TB cases dramatically increased (β3 = 0.008, P = 0.001). The monthly trend of TB cases rose significantly by 0.002 (P = 0.001), indicating an effect over time. In Salas-e Babajani, there was no immediate change in TB cases, but there was a significant long-term decline compared to the period before the earthquake (P = 0.001).

CONCLUSIONS

Earthquake is one of the natural crises that provide the conditions for the increase of TB. Local health policymakers must make plans in these areas to contain TB after the earthquake.

Therapeutic developments for tuberculosis and nontuberculous mycobacterial lung disease

Tuberculosis (TB) drug discovery and development has undergone nothing short of a revolution over the past 20 years. Successful public-private partnerships and sustained funding have delivered a much-improved understanding of mycobacterial disease biology and pharmacology and a healthy pipeline that can tolerate inevitable attrition. Preclinical and clinical development has evolved from decade-old concepts to adaptive designs that permit rapid evaluation of regimens that might greatly shorten treatment duration over the next decade. But the past 20 years also saw the rise of a fatal and difficult-to-cure lung disease caused by nontuberculous mycobacteria (NTM), for which the drug development pipeline is nearly empty. Here, we discuss the similarities and differences between TB and NTM lung diseases, compare the preclinical and clinical advances, and identify major knowledge gaps and areas of cross-fertilization. We argue that applying paradigms and networks that have proved successful for TB, from basic research to clinical trials, will help to populate the pipeline and accelerate curative regimen development for NTM disease.

Hawaiian Volcanic Ash, an Airborne Fomite for Nontuberculous Mycobacteria

Nontuberculous mycobacteria (NTM) are environmentally acquired opportunistic pathogens that can cause chronic lung disease. Within the U.S., Hawai'i shows the highest prevalence rates of NTM lung infections. Here, we investigated a potential role for active volcanism at the Kīlauea Volcano located on Hawai'i Island in promoting NTM growth and diversity. We recovered NTM that are known to cause lung disease from plumbing biofilms and soils collected from the Kīlauea environment. We also discovered viable Mycobacterium avium, Mycobacterium abscessus, and Mycobacterium intracellulare subsp. chimaera on volcanic ash collected during the 2018 Kīlauea eruption. Analysis of soil samples showed that NTM prevalence is positively associated with bulk content of phosphorus, sulfur, and total organic carbon. In growth assays, we showed that phosphorus utilization is essential for proliferation of Kīlauea-derived NTM, and demonstrate that NTM cultured with volcanic ash adhere to ash surfaces and remain viable. Ambient dust collected on O'ahu concurrent with the 2018 eruption contained abundant fresh volcanic glass, suggestive of inter-island ash transport. Phylogenomic analyses using whole genome sequencing revealed that Kīlauea-derived NTM are genetically similar to respiratory isolates identified on other Hawaiian Islands. Consequently, we posit that volcanic eruptions could redistribute environmental microorganisms over large scales. While additional studies are needed to confirm a direct role of ash in NTM dispersal, our results suggest that volcanic particulates harbor and can redistribute NTM and should therefore be studied as a fomite for these burgeoning, environmentally acquired respiratory infections.

Environmental Sources and Transmission of Nontuberculous Mycobacteria

The field of environmental nontuberculous mycobacteria (NTM) is benefiting from a new era of genomics that has catapulted our understanding of preferred niches, transmission, and outbreak investigations. The ability to forecast environmental features that promote or reduce environmental NTM prevalence will greatly improve with coordinated environmental sampling and by elevating the necessity for uniform disease notifications. Studies that synergize environmental biology, isolate notifications, and comparative genomics in prospective, longitudinal studies, particularly during climate changes and weather events, will be useful to solve longstanding NTM public health quandaries.

Assessment of pathogens in flood waters in coastal rural regions: Case study after Hurricane Michael and Florence

The severity of hurricanes, and thus the associated impacts, is changing over time. One of the understudied threats from damage caused by hurricanes is the potential for cross-contamination of water bodies with pathogens in coastal agricultural regions. Using microbiological data collected after hurricanes Florence and Michael, this study shows a dichotomy in the presence of pathogens in coastal North Carolina and Florida. Salmonella typhimurium was abundant in water samples collected in the regions dominated by swine farms. A drastic decrease in Enterococcus spp. in Carolinas is indicative of pathogen removal with flooding waters. Except for the abundance presence of Salmonella typhimurium, no significant changes in pathogens were observed after Hurricane Michael in the Florida panhandle. We argue that a comprehensive assessment of pathogens must be included in decision-making activities in the immediate aftermath of hurricanes to build resilience against risks of pathogenic exposure in rural agricultural and human populations in vulnerable locations.

Spatial Epidemiologic Analysis and Risk Factors for Nontuberculous Mycobacteria Infections, Missouri, USA, 2008-2019

Nontuberculous mycobacteria (NTM) infections are caused by environmental exposure. We describe spatial distribution of NTM infections and associations with sociodemographic factors and flooding in Missouri, USA. Our retrospective analysis of mycobacterial cultures reported to the Missouri Department of Health and Social Services surveillance system during January 1, 2008-December 31, 2019, detected geographic clusters of infection. Multilevel Poisson regression quantified small-area geographic variations and identified characteristics associated with risk for infection. Median county-level NTM infection rate was 66.33 (interquartile range 51-91)/100,000 persons. Risk of clustering was significantly higher in rural areas (rate ratio 2.82, 95% CI 1.90-4.19) and in counties with >5 floodings per year versus no flooding (rate ratio 1.38, 95% CI 1.26-1.52). Higher risk for NTM infection was associated with older age, rurality, and more flooding. Clinicians and public health professionals should be aware of increased risk for NTM infections, especially in similar environments.

A narrative review of nontuberculous mycobacterial pulmonary disease: microbiology, epidemiology, diagnosis, and management challenges

INTRODUCTION

Nontuberculous mycobacteria (NTM) are a diverse group of mycobacterial species that are ubiquitous in the environment. They are opportunistic pathogens that can cause a range of diseases, especially in individuals with underlying structural lung disease or compromised immune systems.

AREAS COVERED

This paper provides an in-depth analysis of NTM infections, including microbiology, environmental sources and transmission pathways, risk factors for disease, epidemiology, clinical manifestations and diagnostic approaches, guideline-based treatment recommendations, drugs under development, and management challenges.

EXPERT OPINION

Future approaches to the management of NTM pulmonary disease will require therapies that are well tolerated, can be taken for a shorter time period and perhaps less frequently, have few drug-drug interactions, and are active against the various strains of pathogens. As the numbers of infections increase, such therapies will be welcomed by clinicians and patients.

Impact of climate change on waterborne infections and intoxications

Progressive climate change holds the potential for increasing human health risks from waterborne infections and intoxications, e. g. through an increase in pathogen concentrations in water bodies, through the establishment of new pathogens or through possible changes in pathogen properties. This paper presents some examples of potential impacts of climate change in Germany. Non-cholera Vibrio occur naturally in seawater, but can proliferate significantly in shallow water at elevated temperatures. In the case of Legionella, climate change could lead to temporary or longer-term increased incidences of legionellosis due to the combination of warm and wet weather. Higher temperatures in piped cold water or lower temperatures in piped hot water may also create conditions conducive to higher Legionella concentrations. In nutrient-rich water bodies, increased concentrations of toxigenic cyanobacteria may occur as temperatures rise. Heavy rainfall following storms or prolonged periods of heat and drought can lead to increased levels of human pathogenic viruses being washed into water bodies. Rising temperatures also pose a potential threat to human health through pathogens causing mycoses and facultatively pathogenic micro-organisms: increased infection rates with non-tuberculous mycobacteria or fungi have been documented after extreme weather events.

Environmental influences on childhood asthma: Climate change

Climate change is a key environmental factor for allergic respiratory diseases, especially in childhood. This review describes the influences of climate change on childhood asthma considering the factors acting directly, indirectly and with their amplifying interactions. Recent findings on the direct effects of temperature and weather changes, as well as the influences of climate change on air pollution, allergens, biocontaminants and their interplays, are discussed herein. The review also focusses on the impact of climate change on biodiversity loss and on migration status as a model to study environmental effects on childhood asthma onset and progression. Adaptation and mitigation strategies are urgently needed to prevent further respiratory diseases and human health damage in general, especially in younger and future generations.

Environmental risk of nontuberculous mycobacterial infection: Strategies for advancing methodology

The National Institute of Allergy and Infectious Diseases organized a symposium in June 2022, to facilitate discussion of the environmental risks for nontuberculous mycobacteria exposure and disease. The expert researchers presented recent studies and identified numerous research gaps. This report summarizes the discussion and identifies six major areas of future research related to culture-based and culture independent laboratory methods, alternate culture media and culturing conditions, frameworks for standardized laboratory methods, improved environmental sampling strategies, validation of exposure measures, and availability of high-quality spatiotemporal data.

A Comprehensive Review and Update on Epidemiology, Symptomatology and Management of Nontuberculous Mycobacteria (NTM)

Nontuberculous mycobacteria (NTM) are free-living organisms ubiquitously present in the environment. In recent times, NTM gained much importance due to the increase in incidence globally. They are potential agents in causing both pulmonary and extrapulmonary infections in both immunocompromised and immunocompetent individuals. The problem arises when the possible NTM cases are misdiagnosed as drug-resistant tuberculosis (DR-TB). Hence, it is essential to correctly identify the NTMs causing disease due to two major reasons. One is to prevent clinicians from starting anti-tuberculous drugs and the other is that treatment regimen differs for certain NTM from tuberculosis. Apart from conventional methods like smear microscopy, culture, in the current era newer diagnostic modalities like matrix-assisted laser desorption of ionization-time of flight mass spectrometry (MALDI TOF MS), line probe assay, genomic sequencing, are used in referral laboratories which allows identification and speciation of the organism. A thorough literature search was done in PubMed, Google Scholar, Cochrane Library, Embase, Scopus on nontuberculous mycobacteria. The search keywords include nontuberculous mycobacteria, atypical mycobacteria, case reports, and original articles on NTM. In this review, we have summarised the current knowledge on epidemiology, pathogenesis, clinical features, and treatment of NTM.

Pulmonary nontuberculous mycobacterial disease in Florida and association with large-scale natural disasters

Background

Little is known about the impact of the ecosystem disruption and its contribution on the non-tuberculosis mycobacteria (NTM) diseases (cases) rate in Florida (FL), a state with a high prevalence of NTM in the United States. We aimed to evaluate the epidemiological distribution of NTM in FL and identify its association with extreme weather events.

Methods

We used OneFlorida Clinical Research Consortium dataset and extracted data on NTM cases using ICD codes 9- CM 031.0 and ICD-10 A31 during 2012–2018. The number of hurricanes during the study period which affected FL were extracted data from the National Hurricane Center (NHC) and the National Oceanic and Atmospheric Administration (NOAA).

Results

Prevalence of NTM gradually increased during the study period. The rate was 2012: 14.3/100,000, 2015; 20.1/100,000 and 2018; 22.6/100,00 except in 2014 where there was an 8% decrease. The incidences were 2012; 6.5/100,00, 2015; 4.9/100,000 and in 2015; 5.4/100,000. Geographical analysis demonstrated a gradual expansion of the NTM cases in Alachua, and Marion Counties throughout the study period. Notably, the 2018 heat map showed higher prevalence of NTM in the northwestern, panhandle region of FL which had been absent in the heat maps for years 2012–2018. High number of the hurricanes was associated with the higher number of the new cases of NTM infection for years 2012, 2016–2018, while the lower number of the hurricanes was associated with the lower number of the new cases of NTM infection for years 2014–2015.

Conclusion

The current study found the prevalence rates of NTM disease in FL rose from 2012 to 2018. A higher prevalence was seen following the hurricanes.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-12115-7.

Continued Upward Trend in Non-Tuberculous Mycobacteria Isolation over 13 Years in a Tertiary Care Hospital in Korea

PURPOSE

Despite decreased prevalence of tuberculosis, the incidence of the diseases associated with nontuberculous mycobacteria (NTM) has been increasing in South Korea and around the world. The present retrospective study was conducted to determine longitudinal changes in the epidemiology and distribution of NTM over 13 years at a tertiary care hospital in Korea.

MATERIALS AND METHODS

We retrospectively analyzed data on Mycobacterium species over 13 years (January 2007 to December 2019) by utilizing the laboratory information system. Mycobacterium species were identified using biochemical tests and PCR-restriction fragment length polymorphism and Mycobacteria GenoBlot assays.

RESULTS

After excluding duplicates from the initial pool of 17996 mycobacterial isolates, 7674 strains were analyzed and 2984 (38.9%) NTM were isolated. The proportion of NTM continuously increased over the 13-year period, from 17.0% in 2007 to 57.5% in 2019. Among the NTM isolates, the most common species were Mycobacterium intracellulare (50.6%), M. avium (18.3%), M. fortuitumcomplex (4.9%), M. abscessus (4.5%), M. gordonae (3.3%), M. kansasii (1.1%), M. chelonae (1.0%), and M. massiliense (0.9%). In patients over the age of 70 years, the proportion of NTM among the isolates increased from 26.6% in 2007 to 62.0% in 2019, and that of M. intracellulare isolates among the NTM increased from 13.9% (11/79) in 2007 to 37.4% (175/468) in 2019.

CONCLUSION

The number of NTM isolates continuously increased over the study period, and the increase in the proportion of M.intracellulare in patients aged over 70 years was notable.

Nontuberculous mycobacterial pulmonary disease: an integrated approach beyond antibiotics

Nontuberculous mycobacterial (NTM) pulmonary disease (PD) is an emerging condition with heterogeneous manifestations from both the microbiological and the clinical point of view. Diagnostic and therapeutic guidelines are available but there are still unmet patients' and physicians' needs, including therapy-related adverse events, symptom control, management of comorbidities, risk of re-exposure to the pathogen and unfavourable outcomes.

In the present review, we provide currently available evidence for an integrated approach to NTM-PD beyond antibiotic therapy. This includes 1) avoiding exposure to environments where mycobacteria are present and careful evaluation of lifestyle and habits; 2) implementing a personalised pulmonary rehabilitation plan and airway clearance techniques to improve symptoms, exercise capacity, health-related quality of life (QoL) and functional capacity in daily living activities; 3) a nutritional evaluation and intervention to improve health-related QoL and to control gastrointestinal side-effects during antimicrobial therapy, particularly in those with low body mass index and history of weight loss; and 4) managing comorbidities that affect disease outcomes, including structural lung diseases, immune status evaluation and psychological support when appropriate.

An integrated approach, including risk factor prevention, management of comorbidities, nutritional evaluation and intervention and pulmonary rehabilitation, should be considered in the optimal management of nontuberculous mycobacterial pulmonary diseasehttps://bit.ly/2YEqvQg

Climate change and infectious diseases in Australia's Torres Strait Islands

OBJECTIVE

This research seeks to identify climate-sensitive infectious diseases of concern with a present and future likelihood of increased occurrence in the geographically vulnerable Torres Strait Islands, Australia. The objective is to contribute evidence to the need for adequate climate change responses.

METHODS

Case data of infectious diseases with proven, potential and speculative climate sensitivity were compiled.

RESULTS

Five climate-sensitive diseases in the Torres Strait and Cape York region were identified as of concern: tuberculosis, dengue, Ross River virus, melioidosis and nontuberculous mycobacterial infection. The region constitutes 0.52% of Queensland's population but has a disproportionately high proportion of the state's cases: 20.4% of melioidosis, 2.4% of tuberculosis and 2.1% of dengue.

CONCLUSIONS

The Indigenous Torres Strait Islander peoples intend to remain living on their traditional country long-term, yet climate change brings risks of both direct and indirect human health impacts. Implications for public health: Climate-sensitive infections pose a disproportionate burden and ongoing risk to Torres Strait Islander peoples. Addressing the causes of climate change is the responsibility of various agencies in parallel with direct action to minimise or prevent infections. All efforts should privilege Torres Strait Islander peoples' voices to self-determine response actions.

Perspectives on the Health Effects of Hurricanes: A Review and Challenges

Hurricanes are devastating natural disasters which dramatically modify the physical landscape and alter the socio-physical and biochemical characteristics of the environment, thus exposing the affected communities to new environmental stressors, which persist for weeks to months after the hurricane. This paper has three aims. First, it conceptualizes potential direct and indirect health effects of hurricanes and provides an overview of factors that exacerbate the health effects of hurricanes. Second, it summarizes the literature on the health impact of hurricanes. Finally, it examines the time lag between the hurricane (landfall) and the occurrence of diseases. Two major findings emerge from this paper. Hurricanes are shown to cause and exacerbate multiple diseases, and most adverse health impacts peak within six months following hurricanes. However, chronic diseases, including cardiovascular disease and mental disorders, continue to occur for years following the hurricane impact.

Symptom Burden and Medication Use Among Patients with Nontuberculous Mycobacterial Lung Disease

Purpose

Respiratory diseases caused by nontuberculous mycobacteria (NTM) have become a significant concern for patients and health care providers. We aimed to compare symptoms experienced during the 2 week period, at a single point in time, by patients with NTM lung disease (NTMLD) who were currently on any medication to treat their NTMLD versus those not on any therapies.

Methods

We analyzed responses to a "Burden of NTM Survey" developed by the COPD Foundation. The study population included 266 individuals with NTMLD. Using adjusted penalized logistic regression models, we determined associations between the self-reported symptoms and the use of any medication to treat NTMLD.

Results

Based on available data, most respondents were aged 50 and older (95.1%), of female gender (93.1%), and had been living with NTMLD for more than 5 years (55.7%). Many respondents reported symptoms that bother them very often or daily. After adjustment for age and gender, duration of living with NTMLD, and other respiratory illnesses, patients on medication had significantly larger odds of reporting difficulty in walking 500 meters without stopping, difficulty in interacting with others, fatigue or lack of energy, feelings of sadness or depression related to illness, and shortness of breath, wheezing or other difficulties.

Conclusion

In this study, patients currently on any medication to treat their NTMLD reported more symptoms associated with their NTMLD. Further investigations are needed to explore whether increased symptoms are related to differences in disease severity and/or medication effects.

Influence of climate variables on the rising incidence of nontuberculous mycobacterial (NTM) infections in Queensland, Australia 2001-2016

International reports indicate a rising incidence of nontuberculous mycobacterial (NTM) disease. Many infectious diseases have seasonal variation in incidence, and major weather events and climate change have been implicated. The aim of this study was to explore the relationship between climate variables and NTM incident cases in Queensland, Australia.

METHODS

NTM data were obtained from the Queensland notifiable conditions database for the period 2001-2016. Rainfall and temperature data were obtained from the Australian Bureau of Meteorology. Poisson regression models were used to assess notification rates (incidence cases per 100,000 population) over time and to estimate incidence rate ratios (IRR). Cross correlation coefficients were used to examine the relationship between rainfall and temperature data and NTM incidence over time in each Hospital and Health Service (HHS).

RESULTS

12,219 NTM cases were reported. The most common species was M. intracellulare (39.1%), followed by M. avium (9.8%), M abscessus (8.5%), M. fortuitum (8.3%), M. chelonae (3.3%), and M. kansasii (2.4%). The estimated incidence rate increased from 11.10 (95% CI 8.10-15.22) in 2001 to 25.88 (95%CI 21.78-30.73) per 100,000 in 2016. The estimated IRR increased for all common species, except M. kansasii. Although increased IRRs were observed for most NTM species, geospatial heterogeneity was observed. The effect of rainfall and temperature on NTM incidence differed between species and geographic regions.

CONCLUSIONS

The incidence of NTM infections increased between 2001 and 2016. Variations in temperature and rainfall may play a role in environmental exposure to some species of NTM. Spatial variation in IRR suggests that there may also be other environmental factors that influence transmission.

Pulmonary non-tuberculous mycobacterial infections: current state and future management

Currently, there is a trend of increasing incidence in pulmonary non-tuberculous mycobacterial infections (PNTM) together with a decrease in tuberculosis (TB) incidence, particularly in developed countries. The prevalence of PNTM in underdeveloped and developing countries remains unclear as there is still a lack of detection methods that could clearly diagnose PNTM applicable in these low-resource settings. Since non-tuberculous mycobacteria (NTM) are environmental pathogens, the vicinity favouring host-pathogen interactions is known as important predisposing factor for PNTM. The ongoing changes in world population, as well as socio-political and economic factors, are linked to the rise in the incidence of PNTM. Development is an important factor for the improvement of population well-being, but it has also been linked, in general, to detrimental environmental consequences, including the rise of emergent (usually neglected) infectious diseases, such as PNTM. The rise of neglected PNTM infections requires the expansion of the current efforts on the development of diagnostics, therapies and vaccines for mycobacterial diseases, which at present, are mainly focused on TB. This review discuss the current situation of PNTM and its predisposing factors, as well as the efforts and challenges for their control.

Prevalence of non-tuberculous mycobacteria in HIV-infected patients admitted to hospital with pneumonia

<sec id="st1"> <title>BACKGROUND</title> People living with the human immunodeficiency virus (PLWH) may be particularly vulnerable to the consequences of non-tuberculous mycobacteria (NTM) given their defective T cell-mediated immunity and high rates of structural lung disease. </sec> <sec id="st2"> <title>OBJECTIVE</title> To determine the prevalence of NTM in PLWH hospitalized with pneumonia and to assess the potential predictors of NTM isolation. </sec> <sec id="st3"> <title>METHODS</title> Secondary data analysis of a prospective cohort study (2007-2011) of early bronchoscopy in PLWH presenting with suspected pneumonia was undertaken. Subjects with any species of NTM, henceforth described as 'NTM of undetermined significance' (NTM-US), isolated from sputum or bronchoalveolar lavage fluid (BALF), were included in the analysis. Potential predictors were chosen a priori. </sec> <sec id="st4"> <title>RESULTS</title> Among 196 HIV-infected subjects hospitalized with pneumonia, 96 had respiratory samples positive for NTM-US, with 91% of all NTM-US isolated from sputum compared with BALF. The overall prevalence of NTM-US was 49% (96/196). More NTM subjects were smokers (P = 0.08), with a history of chronic obstructive pulmonary disease (P = 0.08). Among those with pathogenic NTM, 39% (34/88) would have met American Thoracic Society microbiologic criteria for NTM pulmonary disease (17% of total cohort). </sec> <sec id="st5"> <title>CONCLUSIONS</title> Respiratory cultures, predominantly sputum samples, were positive for NTM-US in 45% of HIV-infected subjects admitted to hospital for pneumonia. Further research is needed to characterize the prevalence of NTM in PLWH and help establish specific diagnostic criteria in this population. </sec>.

The influence of climate change on waterborne disease and Legionella: a review

Climate change is predicted to have a major impact on people's lives with the recent extreme weather events and varying abnormal temperature profiles across the world raising concerns. The impacts of global warming are already being observed, from rising sea levels and melting snow and ice to changing weather patterns. Scientists state unequivocally that these trends cannot be explained by natural variability in climate alone. Human activities, especially the burning of fossil fuels, have warmed the earth by dramatically increasing concentrations of heat-trapping gases in the atmosphere; as these concentrations increase, the more the earth will warm. Climate change and related extreme weather events are being exacerbated sooner than has previously been considered and are already adversely affecting ecosystems and human health by increasing the burden and type of disease at a local level. Changes to the marine environment and freshwater supplies already affect significant parts of the world's population and warmer temperatures, especially in more temperate regions, may see an increased spread and transmission of diseases usually associated with warmer climes including, for example, cholera and malaria; these impacts are likely to become more severe in a greater number of countries. This review discusses the impacts of climate change including changes in infectious disease transmission, patterns of waterborne diseases and the likely consequences of climate change due to warmer water, drought, higher rainfall, rising sea levels and flooding.

Increasing Non-tuberculous Mycobacteria Infections in Veterans With COPD and Association With Increased Risk of Mortality

Background: There are limited data on the epidemiology of Non-tuberculous mycobacteria (NTM) infections among patients with COPD, particularly in the veteran population. This study examined the prevalence, incidence, and mortality of pulmonary NTM infections among veterans with COPD population in the United States.

Methods: We analyzed nationwide data from Veterans Affairs Hospitals from 2001 to 2015. First, we determined the incidence and prevalence rates and geographic distribution of NTM infections among veterans with COPD and then we evaluated the association between NTM infections with mortality among veterans with COPD. Pulmonary NTM and COPD diagnosis were defined based on charting claims for each condition on ≥2 occasions and ≥30 days apart. COPD diagnoses had to precede diagnosis of NTM. Cox Proportional-Hazards Regression was performed to determine the dependency of survival time of COPD patients with NTM.

Results: The incidence and prevalence rates of NTM rose over the study period, with a sharp rise in incidence after 2012. The areas with the highest NTM period prevalence were Puerto Rico (370), followed by Florida (351) and District of Columbia (309) in 100,000 COPD population. Mortality registered for those patients with COPD Patients and NTM infection was 1.43 times higher compared to those that were uninfected.

Conclusions: NTM rates have been increasing in veterans with COPD since 2012. NTM infection is associated with increased risk of mortality. This highlights the importance of identifying preventable risk factors associated with NTM infections in subjects with COPD.

Global Environmental Nontuberculous Mycobacteria and Their Contemporaneous Man-Made and Natural Niches

Seminal microbiological work of environmental nontuberculous mycobacteria (NTM) includes the discovery that NTM inhabit water distribution systems and soil, and that the species of NTM found are geographically diverse. It is likely that patients acquire their infections from repeated exposures to their environments, based on the well-accepted paradigm that water and soil bioaerosols - enriched for NTM - can be inhaled into the lungs. Support comes from reports demonstrating NTM isolated from the lungs of patients are genetically identical to NTM found in their environment. Well documented sources of NTM include peat-rich soils, natural waters, drinking water, hot water heaters, refrigerator taps, catheters, and environmental amoeba. However, NTM have also been recovered in biofilms from ice machines, heated nebulizers, and heater-cooler units, as well as seat dust from theaters, vacuum cleaners, and cobwebs. New studies on the horizon aim to significantly expand the current knowledge of environmental NTM niches in order to improve our current understanding of the specific ecological factors driving the emergence of NTM lung disease. Specifically, the Hawaiian Island environment is currently being studied as a model to identify other point sources of exposure as it is the U.S. state with the highest number of NTM lung disease cases. Because of its geographic isolation and unique ecosystem, the Hawaiian environment is being probed for correlative factors that may promote environmental NTM colonization.

The many lives of nontuberculous mycobacteria

Nontuberculous mycobacteria (NTM) include species that colonize human epithelia, as well as species that are ubiquitous in soil and aquatic environments. NTM that primarily inhabit soil and aquatic environments include the Mycobacterium avium complex (MAC, M. avium and Mycobacterium intracellulare) and the Mycobacterium abscessus complex (MABSC, M. abscessus subspecies abscessus, massiliense, and bolletii), and can be free-living, biofilm-associated, or amoeba-associated. Although NTM are rarely pathogenic in immunocompetent individuals, those who are immunocompromised - due to either an inherited or acquired immunodeficiency - are highly susceptible to NTM infection (NTMI). Several characteristics such as biofilm formation and the ability of select NTM species to form distinct colony morphotypes all may play a role in pathogenesis not observed in the related, well-characterized pathogen Mycobacterium tuberculosis The recognition of different morphotypes of NTM has been established and characterized since the 1950s, but the mechanisms that underlie colony phenotype change and subsequent differences in pathogenicity are just beginning to be explored. Advances in genomic analysis have led to progress in identifying genes important to the pathogenesis and persistence of MAC disease as well as illuminating genetic aspects of different colony morphotypes. Here we review recent literature regarding NTM ecology and transmission, as well as the factors which regulate colony morphotype and pathogenicity.

Mycobacterium abscessus Displays Fitness for Fomite Transmission

Mycobacterium abscessus is a rapidly growing nontuberculous mycobacterium (NTM) increasingly reported in soft tissue infections and chronic lung diseases, including cystic fibrosis. The environmental source of M. abscessus has not been definitively identified, but NTM have been detected in soil and water. To determine the potential of soil-derived M. abscessus as an infectious source, we explored the association, growth, and survival of M. abscessus with defined mineral particulates, including kaolin, halloysite, and silicone dioxide, and house dust as possible M. abscessus fomites. M. abscessus physically associated with particulates, and the growth of M. abscessus was enhanced in the presence of both kaolin and house dust. M. abscessus survived desiccation for 2 weeks but was not viable after 3 weeks. The rate of decline of M. abscessus viability during desiccation was reduced in the presence of house dust. The evidence for enhanced growth and survival of M. abscessus during alternating growth and drying periods suggests that dissemination could occur when in wet or dry environments. These studies are important to understand environmental survival and acquisition of NTM.IMPORTANCE The environmental source of pulmonary Mycobacterium abscessus infections is not known. Fomites are nonliving carriers of infectious agents and may contribute to acquisition of M. abscessus This study provides evidence that M. abscessus growth is enhanced in the presence of particulates, using kaolin, an abundant natural clay mineral, and house dust as experimental fomites. Moreover, M. abscessus survived desiccation for up to 2 weeks in the presence of house dust, kaolin, and several chemically defined mineral particulates; mycobacterial viability during extended periods of dessication was enhanced by the presence of house dust. The growth characteristics of M. abscessus with particulates suggest that a fomite mechanism of transmission may contribute to M. abscessus acquisition, which may lead to strategies to better control infections by M. abscessus and related organisms.

The Goldilocks model of immune symbiosis with Mycobacteria and Candida colonizers

Mycobacteria and Candida species include significant human pathogens that can cause localized or disseminated infections. Although these organisms may appear to have little in common, several shared pathways of immune recognition and response are important for both control and infection-related pathology. In this article, we compare and contrast the innate and adaptive components of the immune system that pertain to these infections in humans and animal models. We also explore a relatively new concept in the mycobacterial field: biological commensalism. Similar to the well-established model of Candida infection, Mycobacteria species colonize their human hosts in equilibrium with the immune response. Perturbations in the immune response permit the progression to pathologic disease at the expense of the host. Understanding the immune factors required to maintain commensalism may aid with the development of diagnostic and treatment strategies for both categories of pathogens.

Nontuberculous mycobacterial infection of the musculoskeletal system in immunocompetent hosts

BACKGROUND

Nontuberculous mycobacteria (NTM) were considered saprophytic organisms for many years but now are recognized as human pathogens. Although humans are routinely exposed to NTM, the rate of clinical infection is low. Such infections usually occur in the elderly and in patients who are immunocompromised. However, there has been an increasing incidence in recent years of infections in immunocompetent hosts. NTM infections in immunocompetent individuals are secondary to direct inoculation either contamination from surgical procedures or penetrating injuries rather than hematogenous dissemination. Clinically and on histopathology, musculoskeletal infections caused by NTM resemble those caused by Mycobacterium tuberculosis but are mostly resistant to routine antituberculosis medicines.

MATERIALS AND METHODS

Six cases of NTM infection in immunocompetent hosts presenting to the department from 2004 to 2015 were included in study. Of which two cases (one patella and one humerus) of infection were following an open wound due to trauma while two cases (one hip and one shoulder) of infection were by inoculation following an intraarticular injection for arthrogram of the joint, one case was infection following arthroscopy of knee joint and one case (calcaneum) was infection following local injection for the treatment of plantar fasciitis. All patients underwent inaging and tissue diagnosis with samples being sent for culture, staining, and histopathology.

RESULTS

Clinical suspicion of NTM inoculation led to the correct diagnosis (four cases with culture positive and two cases with histopathological diagnosis). There treatment protocol for extrapulmonary NTM infection was radical surgical debridement and medical management based on drug sensitivity testing in culture positive cases. At a mean follow up of 3 years (range1-9 years) all patients had total remission and excellent results.

CONCLUSIONS

Whenever a case of chronic granulomatous infection is encountered that does not respond to standard anti-tuberculous treatment, with a history of open trauma, surgical intervention, or injection as shown in this study, a possible NTM infection should be considered and managed appropriately.

Treatment of Non-Tuberculous Mycobacterial Lung Disease

Treatment of non-tuberculous mycobacterial lung disease (NTM-LD) is challenging for several reasons including the relative resistance of NTM to currently available drugs and the difficulty in tolerating prolonged treatment with multiple drugs. Yet-to-be-done, large, multicenter, prospective randomized studies to establish the best regimens will also be arduous because multiple NTM species are known to cause human lung disease, differences in virulence and response to treatment between different species and strains within a species will make randomization more difficult, the need to distinguish relapse from a new infection, and the difficulty in adhering to the prescribed treatment due to intolerance, toxicity, and/or drug-drug interactions, often necessitating modification of therapeutic regimens. Furthermore, the out-of-state resident status of many patients seen at the relatively few centers that care for large number of NTM-LD patients pose logistical issues in monitoring response to treatment. Thus, current treatment regimens for NTM-LD is largely based on small case series, retrospective analyses, and guidelines based on expert opinions. It has been nearly 10 years since the publication of a consensus guideline for the treatment of NTM-LD. This review is a summary of the available evidence on the treatment of the major NTM-LD until more definitive studies and guidelines become available.