Pulmonary infections due to nontuberculous mycobacteria (NTM) are increasingly recognized worldwide. Although over 150 different species of NTM have been described, pulmonary infections are most commonly due to Mycobacterium avium complex (MAC), Mycobacterium kansasii, and Mycobacterium abscessus. The identification of these organisms in pulmonary specimens does not always equate with active infection; supportive radiographic and clinical findings are needed to establish the diagnosis. It is difficult to eradicate NTM infections. A prolonged course of therapy with a combination of drugs is required. Unfortunately, recurrent infection with new strains of mycobacteria or a relapse of infection caused by the original organism is not uncommon. Surgical resection is appropriate in selected cases of localized disease or in cases in which the infecting organism is resistant to medical therapy. Additionally, surgery may be required for infections complicated by hemoptysis or abscess formation. This review will summarize the practical aspects of the diagnosis and management of NTM thoracic infections, with emphasis on the indications for surgery and the results of surgical intervention. The management of NTM disease in patients with human immunodeficiency virus (HIV) infections is beyond the scope of this article and, unless otherwise noted, comments apply to hosts without HIV infection

/pdf/nontuberculous-mycobacterial-pulmonary-infections-4nqntofrty.pdf

Nontuberculous mycobacterial pulmonary infections

Numerous studies have revealed a continuous increase in the worldwide incidence and prevalence of nontuberculous mycobacteria (NTM) diseases, especially pulmonary Mycobacterium avium complex (MAC) diseases. Although it is not clear why NTM diseases have been increasing, one possibility is an increase of mycobacterial infection sources in the environment. Thus, in this review, we focused on the infection sources of pathogenic NTM, especially MAC. The environmental niches for MAC include water, soil, and dust. The formation of aerosols containing NTM arising from shower water, soil, and pool water implies that these niches can be infection sources. Furthermore, genotyping has shown that clinical isolates are identical to environmental ones from household tap water, bathrooms, potting soil, and garden soil. Therefore, to prevent and treat MAC diseases it is essential to identify the infection sources for these organisms, because patients with these diseases often suffer from reinfections and recurrent infections with them. In the environmental sources, MAC and other NTM organisms can form biofilms, survive within amoebae, and exist in a free-living state. Mycobacterial communities are also likely to occur in these infection sources in households. Water distribution systems are a transmission route from natural water reservoirs to household tap water. Other infection sources include areas with frequent human contact, such as soil and bathrooms, indicating that individuals may carry NTM organisms that concomitantly attach to their household belongings. To explore the mechanisms associated with the global spread of infection and MAC transmission routes, an epidemiological population-wide genotyping survey would be very useful. A good example of the power of genotyping comes from M. avium subsp. hominissuis, where close genetic relatedness was found between isolates of it from European patients and pigs in Japan and Europe, implying global transmission of this bacterium. It is anticipated that whole genome sequencing technologies will improve NTM surveys so that the mechanisms for the global spread of MAC disease will become clearer in the near future. Better understanding of the niches exploited by MAC and its ecology is essential for preventing MAC infections and developing new methods for its effective treatment and elimination.

/pdf/infection-sources-of-a-common-non-tuberculous-mycobacterial-3qsl7n8he8.pdf

Infection Sources of a Common Non-tuberculous Mycobacterial Pathogen, Mycobacterium avium Complex.

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.

/pdf/global-environmental-nontuberculous-mycobacteria-and-their-17bwmr8i0g.pdf

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

Nontuberculous mycobacteria (NTM) are emerging human pathogens, causing a wide range of clinical diseases affecting individuals who are immunocompromised and who have underlying health conditions. NTM are ubiquitous in the environment, with certain species causing opportunistic infection in humans, including Mycobacterium avium and Mycobacterium abscessus. The incidence and prevalence of NTM infections are rising globally, especially in developed countries with declining incidence rates of M. tuberculosis infection. Mycobacterium avium, a slow-growing mycobacterium, is associated with Mycobacterium avium complex (MAC) infections that can cause chronic pulmonary disease, disseminated disease, as well as lymphadenitis. M. abscessus infections are considered one of the most antibiotic-resistant mycobacteria and are associated with pulmonary disease, especially cystic fibrosis, as well as contaminated traumatic skin wounds, postsurgical soft tissue infections, and healthcare-associated infections (HAI). Clinical manifestations of diseases depend on the interaction of the host’s immune response and the specific mycobacterial species. This review will give a general overview of the general characteristics, vulnerable populations most at risk, pathogenesis, treatment, and prevention for infections caused by Mycobacterium avium, in the context of MAC, and M. abscessus.

https://www.mdpi.com/2077-0383/9/8/2541/pdf

General Overview of Nontuberculous Mycobacteria Opportunistic Pathogens: Mycobacterium avium and Mycobacterium abscessus.

Pulmonary infections with nontuberculous mycobacteria (NTM) are recognized as a problem in immunodeficient individuals and are increasingly common in older people with no known immune defects. NTM are found in soil and water, but factors influencing transmission from the environment to humans are mostly unknown. Studies of the epidemiology of NTM disease have matched some clinical isolates of NTM with isolates from the patient's local environment. Definitive matching requires strain level differentiation based on molecular analyses, including partial sequencing, PCR-restriction fragment length polymorphism (RFLP) analysis, random amplified polymorphic DNA (RAPD) PCR, repetitive element (rep-) PCR and pulsed field gel electrophoresis (PFGE) of large restriction fragments. These approaches have identified hospital and residential showers and faucets, hot-tubs and garden soil as sources of transmissible pathogenic NTM. However, gaps exist in the literature, with many clinical isolates remaining unidentified within environments that have been tested, and few studies investigating NTM transmission in developing countries. To understand the environmental reservoirs and transmission routes of pathogenic NTM, different environments, countries and climates must be investigated.

Review: Environmental mycobacteria as a cause of human infection

Adrian Muwonge1, Ashemeire Patience4, Clovice Kankya2, Demelash Biffa5, Eystein Skjerve1 and James Oloya3 1Department of Food Safety and Infection Biology, Norwegian School of Veterinary Science 2Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, Makerere University 3Department of Epidemiology and Biostatistics/ Population Health, college of Public health, 132 Coverdell centre, University of Georgia Athens, 4Faculty of Community Psychology, Makerere University, 5Schools of Veterinary Medicine, Hawassa University, 1Norway 2,4Uganda 3USA 5Ethiopia

/pdf/non-tuberculous-mycobacteria-in-uganda-a-problem-or-not-1h9mffpcq4.pdf

Non-Tuberculous Mycobacteria in Uganda: A Problem or Not?

Two types of lechwe antelopes exclusively exist in their natural ecosystems in Zambia; the Black lechwe (Kobus leche smithemani) and the Kafue lechwe (Kobus leche kafuensis). Despite inhabiting similar ecosystems, tuberculosis has been reported in Kafue lechwe without its documentation in Black lechwe antelopes. However, the past few decades have seen a drastic decline in both lechwe populations. Whereas studies have postulated that infectious diseases such as tuberculosis are having a negative impact on the Kafue lechwe population, no information is available on Black lechwe antelopes. Thus this study was conducted to investigate tuberculosis in Black lechwe antelopes of the Bangweulu swamps in comparison with the Kafue lechwe antelopes of Lochinvar. A total of 44 lechwe antelopes (Black (n = 30): Kafue (n = 14) were sampled from Bangweulu and Lochinvar respectively. A positive case was defined with findings of gross lesions with Ziehl Nielsen and culture confirmation. Out of the 14 animals examined in Lochinvar, 21.4% [95% CI: 15.4, 44.4%] had necropsy lesions consistent with tuberculosis. The corresponding samples from 30 Black lechwe of Bangweulu yielded negative results on all the three tests. Current findings from this study intimate the possible absence of tuberculosis in Black lechwe antelopes whilst confirming the presence of tuberculosis in Kafue lechwe of the Kafue basin. The absence of tuberculosis in the Black lechwe suggests that the observed population decline may not be caused by tuberculosis. However, without detailed molecular epidemiological studies it is not possible to determine the association of M. bovis infection in sympatric animal populations. The possible role of transmission of tuberculosis between wildlife and cattle is discussed herein. Findings

/pdf/failure-to-detect-tuberculosis-in-black-lechwe-antelopes-3862j28qvf.pdf

Failure to detect tuberculosis in Black lechwe antelopes (Kobus leche smithemani) in Zambia.

In sub-Saharan African arid pastoral regions, the socio-behavioral indigenous knowledge mystical systems associated with actions and response by communities to mycobacterial infections in the pastoral ecosystems of Uganda remains largely unknown in Uganda and across the African continent. These drivers are important as they often magnify the problems linked to co-infection with HIV/AIDS. This study sought to determine the socio-behavioral, indigenous knowledge mystical systems and other factors associated with mycobacterial infections and their management among the pastoralist communities. Socio-demographic, environmental, and household-level behavioral and attitudinal variables data was collected through a cross sectional questionnaire-based study administered to a total of 301 pastoralists from Mubende and Nakasongola pastoral districts of Uganda. In addition, key informant interviews and focus group discussions were conducted. Consumption of raw and half cooked animals’ products, drinking untreated water, and smoking as well as sharing of cigarette sticks and drinking straws, coughing and spitting, and excessive alcoholism were the socio-behaviors perceived to expose the pastoralist communities to mycobacterial infections. Stigmatization was related to chronic illness and faith-based perceptions facilitated mycobacterial infection transmission. Involvement in the risky production actions and social livelihood ventures such as charcoal production are perceived as being responsible for mycobacterial

The role of social behavior in mycobacterial infection management: a case study of pastoral communities of uganda

Background: The importance of non-tuberculous mycobacteria (NTM) infections in humans and animals in subSaharan Africa at the human-environment-livestock-wildlife interface has recently received increased attention. NTM are environmental opportunistic pathogens of humans and animals. Recent studies in pastoral ecosystems of Uganda detected NTM in humans with cervical lymphadenitis and cattle with lesions compatible with bovine tuberculosis. However, little is known about the source of these mycobacteria in Uganda. The aim of this study was to isolate and identify NTM in the environment of pastoral communities in Uganda, as well as assess the potential risk factors and the public health significance of NTM in these ecosystems. Method: A total of 310 samples (soil, water and faecal from cattle and pigs) were examined for mycobacteria. Isolates were identified by the INNO-Lipa test and by 16S rDNA sequencing. Additionally, a questionnaire survey involving 231 pastoralists was conducted during sample collection. Data were analysed using descriptive statistics followed by a multivariable logistic regression analysis. Results: Forty-eight isolates of NTM were detected; 25.3% of soil samples, 11.8% of water and 9.1% from animal faecal samples contained mycobacteria. Soils around water sources were the most contaminated with NTM (29.8%). Of these samples, M. fortuitum-peregrinum complex, M. avium complex, M. gordonae, and M. nonchromogenicum were the most frequently detected mycobacteria. Drinking untreated compared to treated water (OR = 33), use of valley dam versus stream water for drinking and other domestic use (OR = 20), sharing of water sources with wild primates compared to antelopes (OR = 4.6), sharing of water sources with domestic animals (OR = 5.3), and close contact with cattle or other domestic animals (OR = 13.8) were the most plausible risk factors for humans to come in contact with NTM in the environment. Conclusions: The study detected a wide range of potentially pathogenic NTM from the environment around the pastoral communities in Uganda. Drinking untreated water and living in close contact with cattle or other domestic animals may be risk factors associated with the possibility of humans and animals acquiring NTM infections from these ecosystems.

Isolation of non-tuberculous mycobacteria from pastoral ecosystems of Uganda

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Non-Tuberculous Mycobacteria in Uganda: A Problem or Not?

Failure to detect tuberculosis in Black lechwe antelopes (Kobus leche smithemani) in Zambia.

The role of social behavior in mycobacterial infection management: a case study of pastoral communities of uganda

Isolation of non-tuberculous mycobacteria from pastoral ecosystems of Uganda