Nutritional status and eating disorders: neglected risks factor for nontuberculous mycobacterial lung disease?

Host microbiome in tuberculosis: disease, treatment, and immunity perspectives

Tuberculosis (TB), an airborne pulmonary disease caused by Mycobacterium tuberculosis (M. tb), poses an unprecedented health and economic burden to most of the developing countries. Treatment of TB requires prolonged use of a cocktail of antibiotics, which often manifest several side effects, including stomach upset, nausea, and loss of appetite spurring on treatment non-compliance and the emergence of antibiotic resistant M. tb. The anti-TB treatment regimen causes imbalances in the composition of autochthonous microbiota associated with the human body, which also contributes to major side effects. The microbiota residing in the gastrointestinal tract play an important role in various physiological processes, including resistance against colonization by pathogens, boosting host immunity, and providing key metabolic functions. In TB patients, due to prolonged exposure to anti-tuberculosis drugs, the gut microbiota significantly loses its diversity and several keystone bacterial taxa. This loss may result in a significant reduction in the functional potency of the microbiota, which is a probable reason for poor treatment outcomes. In this review, we discuss the structural and functional changes of the gut microbiota during TB and its treatment. A major focus of the review is oriented to the gut microbial association with micronutrient profiles and immune cell dynamics during TB infection. Furthermore, we summarize the acquisition of anti-microbial resistance in M. tb along with the microbiome-based therapeutics to cure the infections. Understanding the relationship between these components and host susceptibility to TB disease is important to finding potential targets that may be used in TB prevention, progression, and cure.

Mycobacterium abscessus: It’s Complex

Mycobacterium abscessus (M. abscessus) is an opportunistic pathogen usually colonizing abnormal lung airways and is often seen in patients with cystic fibrosis. Currently, there is no vaccine available for M. abscessus in clinical development. The treatment of M. abscessus-related pulmonary diseases is peculiar due to intrinsic resistance to several commonly used antibiotics. The development of either prophylactic or therapeutic interventions for M. abscessus pulmonary infections is hindered by the absence of an adequate experimental animal model. In this review, we outline the critical elements related to M. abscessus virulence mechanisms, host–pathogen interactions, and treatment challenges associated with M. abscessus pulmonary infections. The challenges of effectively combating this pathogen include developing appropriate preclinical animal models of infection, developing proper diagnostics, and designing novel strategies for treating drug-resistant M. abscessus.

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.

Nontuberculous mycobacterial lung infections in patients with eating disorders: plausible mechanistic links in a case series

Nontuberculous mycobacteria (NTM) are widely distributed in the environment and are almost always acquired into the lungs by bioaerosol inhalation or aspiration of NTM-contaminated water, biofilms, and soil. NTM are increasingly recognized as causes of lung diseases in immunocompetent hosts, a not insignificant number of whom have a life-long or nearly life-long slender body habitus as well as thoracic cage abnormalities such as scoliosis and pectus excavatum. While several hypotheses have been offered to explain the purported increase in susceptibility to NTM lung disease in such individuals, the precise explanation remains unknown. We described three patients with eating disorders associated with severe malnutrition and either purging behaviors or other risks for aspiration who were diagnosed with NTM lung infections-the largest number of such patients to date in a single report. We discuss the clinical and experimental evidence that low body weight and chronic vomiting with attendant jeopardy for aspiration, as seen in patients with eating disorders, may represent risk factors for NTM lung disease. We also speculate the possibility of occult and undiagnosed eating disorders in some of the slender NTM lung disease patients with no known risk factors for the opportunistic infection other than their low body weight.

Extremely severe anorexia nervosa: Hospital course of 354 adult patients in a clinical nutrition-eating disorders-unit

BACKGROUND AND AIMS

The clinical nutrition-eating disorders-unit in Raymond Poincaré Hospital is a reference center for the management of severe malnutrition and its complications in patients with anorexia nervosa (AN). The purpose of this study is to specify socio-demographic, anamnesic and clinical characteristics of AN patients hospitalized for extreme malnutrition, to identify types and prevalence of medical complications presented during their hospitalization for refeeding and the evolution of patients nutritional status.

METHODS

Demographic, clinical and paraclinical data of 354 severely malnourished AN patients were collected, during their first hospitalization in the unit, between November 1997 and January 2014, through medical records. The prevalence of medical complications was compared between the 2 AN subtypes (restricting and binging-purging).

RESULTS

339 patients were female and mean age was 28.7 ± 10.7 years old. Duration of AN was 9.5 ± 9 years, 173 (48.9%) patients had a restricting AN subtype. BMI at admission was 12.2 ± 1.6 kg/m², 280 (79.3%) patients had already been hospitalized for AN in other hospitals before. Psychiatric comorbidities were present in 168 (47.5%) patients. Associated somatic comorbidities concerned 70 (19.8%) patients. Outcomes during hospitalization were marked by 4.1 ± 3.9 kg weight gain on 36.9 ± 30.5 days. Enteral nutrition was provided in 304 (85.9%) patients. Main medical complications during hospitalization were: anemia (79%), neutropenia (53.9%), hypertransaminasemia (53.7%), osteoporosis (46.3%), hypokalemia (39.5%), hypophosphatemia (26%), hypoglycemia (13.8%), infectious complications (24.3%), cardiac dysfunction (7.1%), and proven gelatinous bone marrow transformation (6.5%). Hypokalemia was more frequent in binging-purging subtype. Lympho-neutropenia and hypertransaminasemia were more frequent in restricting subtype. During their hospitalization, 35 (10%) patients were referred to medical intensive care unit and 5 patients died.

CONCLUSIONS

AN patients hospitalized for severe malnutrition in a specialized clinical nutrition unit have severe and frequent medical complications. Psychiatric comorbidities are also frequent and could complicate medical care. A specialized and multidisciplinary management of these patients is therefore essential.

Mycobacterium szulgai pulmonary infection in a woman with anorexia nervosa

A 40-year-old woman with severe anorexia nervosa was found to have a bilateral pulmonary infection with rare atypical mycobacterium Mycobacterium szulgai. Of note, she had no preexisting structural lung disease or history of tuberculosis, smoking, or HIV. Current data suggest that both impaired cell-mediated immunity and altered respiratory mechanics are risk factors for mycobacterial infection in patients with anorexia nervosa.

[Treating the somatic complications of anorexia]

Anorexia can cause serious somatic complications, linked to undernutrition or associated pathological behaviours. The care pathway drawn up by a multi-discipline team is a real therapeutic challenge. Oral nutritional supplements, enteral nutrition and parenteral nutrition are three possible forms of nutritional assistance.

Comparison of the incidence between tuberculosis and nontuberculous mycobacterial disease after gastrectomy

PURPOSE

Gastrectomy is a well-known risk factor for tuberculosis (TB). However, little data are available regarding the relationship between gastrectomy and the risk of nontuberculous mycobacterial (NTM) disease. Here, we investigated the incidence of TB and NTM lung disease in gastrectomized patients.

METHOD

New cases of TB and NTM lung infection or disease were examined among patients who had undergone gastrectomy due to gastric cancer from 2003 to 2009 at a tertiary referral hospital in South Korea. Annualized incidence rates for cases were compared with those of the general population.

RESULTS

This study included a total of 2,684 patients. New mycobacterial cases were found in 41 patients. Cases of TB and NTM lung infection were 35 (85 %) and 6 (15 %) including 2 NTM lung disease cases, respectively. Annualized crude incidence rates for TB, NTM lung infection, and NTM lung disease were 327/100,000, 56/100,000, and 19/100,000, respectively. The age-standardized incidence rate of TB was significantly higher in gastrectomized patients than in the general population. However, the standardized incidences of NTM lung infection and disease were not significantly different from those of non-gastrectomized patients. Patients with NTM lung infection frequently exhibited comorbid chronic lung disease, while those with TB were more frequently found to have fibronodular lesions on preoperative chest radiography.

CONCLUSIONS

Gastrectomy does not appear to increase the risk of NTM lung disease. However, NTM lung infection or disease should be considered as a differential diagnosis of pulmonary TB in gastrectomized patients accompanying chronic lung disease.