Incidence of tuberculous and non-tuberculous mycobacteria, differentiated by multiplex PCR, in clinical specimens of a large general hospital

Epidemiology of infection by pulmonary non-tuberculous mycobacteria in French Guiana 2008–2018

Introduction

Unlike diseases caused by Mycobacterium tuberculosis, M. leprae and M. ulcerans, the epidemiology of pulmonary non-tuberculous mycobacteria (PNTM) has not received due attention in French Guiana. The main objective of the current study was to define the incidence of these PNTM infections: NTM pulmonary diseases (NTM-PD) and casual PNTM isolation (responsible of latent infection or simple colonization). The secondary objectives were to determine species diversity and geographic distribution of these atypical mycobacteria.

Methods

A retrospective observational study (2008–2018) of French Guiana patients with at least one PNTM positive respiratory sample in culture was conducted. Patients were then classified into two groups: casual PNTM isolation or pulmonary disease (NTM-PD), according to clinical, radiological and microbiological criteria defined by the American Thoracic Society / Infectious Disease Society of America (ATS / IDSA) in 2007.

Results

178 patients were included, out of which 147 had casual PNTM isolation and 31 had NTM-PD. Estimated annual incidence rate of respiratory isolates was 6.17 / 100,000 inhabitants per year while that of NTM-PD was 1.07 / 100,000 inhabitants per year. Among the 178 patients, M. avium complex (MAC) was the most frequently isolated pathogen (38%), followed by M. fortuitum then M. abscessus (19% and 6% of cases respectively), the latter two mycobacteria being mainly found in the coastal center region. Concerning NTM-PD, two species were mainly involved: MAC (81%) and M. abscessus (16%).

Discussion/Conclusion

This is the first study on the epidemiology of PNTM infections in French Guiana. PNTM’s incidence looks similar to other contries and metropolitan France and NTM-PD is mostly due to MAC and M.abscessus. Although French Guiana is the French territory with the highest tuberculosis incidence, NTM should not be overlooked.

Species Distribution and Isolation Frequency of Nontuberculous Mycobacteria, Uruguay

Nontuberculous mycobacteria (NTM) increasingly are recognized as opportunistic pathogens of humans. NTM species distribution is well documented in Europe and North America, but data from other regions are scarce. We assessed NTM isolation frequency and species distribution in Uruguay during 2006–2018.

Nontuberculous mycobacterial infections in a Brazilian pediatric population: a seven-year survey

The aim of this study was to describe the frequency of nontuberculous mycobacteria (NTM) isolation and their related outcomes among pediatric patients of a Brazilian university hospital from 2012 to 2019. NTM were identified in different clinical samples by microbiological culture and molecular-based methods. NTM were isolated from 14 patients, out of whom four (27%) were infected and were treated accordingly. Two were infected with Mycobacterium avium complex (MAC), two with M. abscessus complex (MABSC) and one with M. intracellulare. Two patients had cystic fibrosis-related lung disease and improved after successful NTM eradication. One patient was HIV-positive and died. One patient had severe combined immunodeficiency (SCID)-related pneumonia and is currently being followed-up. We conclude that NTM frequency in our center was low among pediatric patients. Whether this is inherent to Brazilian patients, due to the broad coverage of the Bacille Calmette-Guérin (BCG) vaccine in Brazil, or a result of underdiagnosis remains to be elucidated.

HIV-negative pulmonary disease caused by nontuberculous mycobacteria in Southern Brazil: clinical and microbiological characterization

Background

Nontuberculous mycobacteria (NTM) have been identified with increasing frequency in the clinical practice. The aim of this study was to characterize NTM isolates in respiratory specimens from patients with pulmonary disease and to correlate this with clinical/radiological findings, decision to start treatment and outcomes.

Methods

A cross-sectional descriptive study was performed and included all patients who had at least one NTM isolated in respiratory specimens between 2011 and 2014. NTM culture was performed in liquid medium followed by immunochromatographic identification (anti-MPT64). Species identification was based on nucleic acid amplification followed by restriction analysis of a 441 bp fragment of the hsp65 gene (hsp65 PRA) and patients' records were reviewed.

Results

From 14,394 cultures in 4 years, 590 (4.10%) grew NTM and 305 (51.7%) isolates were characterized till species level, representing 290 patients including those with and without human immunodeficiency virus (HIV) infection. Two hundred and eleven non-HIV patients had NTM isolated from respiratory specimens, 49 (23.2%) had criteria for active disease based on the American Thoracic Society (ATS) 2007. The majority was men above 51 years old and M. intracellulare was detected in 59.2% (29/49), followed by M. avium 14.3% (7/49), and M. abscessus 12.2% (6/49).

Conclusions

Old age, nodular and nodular/bronchiectasis radiographic pattern, previous tuberculosis (TB) treatment and M. intracellulare were more frequent among NTM-disease patients compared to those only colonized. Positive culture and maintenance of clinical symptoms (poor outcome) was a rule when M. abscessus caused NTM-disease. Positive acid-fast smear in respiratory specimen is a strong predictor of disease.

Non-tuberculous mycobacteria: baseline data from three sites in Papua New Guinea, 2010-2012

OBJECTIVE

To determine the proportion of non-tuberculous mycobacteria (NTM) in samples of pulmonary tuberculosis (TB) cases from Papua New Guinea who were diagnosed using acid-fast microscopy.

METHODS

As part of a case detection study for TB, conducted in three provincial hospitals in Papua New Guinea, sputum samples of suspected tuberculous cases aged 15 years or older were collected from November 2010 to July 2012. Mycobacterial species isolated from sputum and grown in culture were examined to distinguish between NTM and the Mycobacterium tuberculosis complex (MTBC).

RESULTS

NTM were detected in 4% (9/225) of sputum samples grown in culture. Five (2.2%) of them were identified as NTM only and four (1.8%) were identified as mixed cultures containing both MTBC and NTM. Four different NTM species were identified; M. fortuitum, M. intracellulare, M. terrae and M. avium.

DISCUSSION

This is the first report from Papua New Guinea identifying NTM in three different locations. As NTM cannot be distinguished from M. tuberculosis through smear microscopy, the presence of NTM can lead to a false-positive diagnosis of tuberculosis. The prevalence of NTM should be determined and a diagnostic algorithm developed to confirm acid-fast bacilli in a smear as M. tuberculosis.

The looming tide of nontuberculous mycobacterial infections in Portugal and Brazil

Nontuberculous mycobacteria (NTM) are widely disseminated in the environment and an emerging cause of infectious diseases worldwide. Their remarkable natural resistance to disinfectants and antibiotics and an ability to survive under low-nutrient conditions allows NTM to colonize and persist in man-made environments such as household and hospital water distribution systems. This overlap between human and NTM environments afforded new opportunities for human exposure, and for expression of their often neglected and underestimated pathogenic potential. Some risk factors predisposing to NTM disease have been identified and are mainly associated with immune fragilities of the human host. However, infections in apparently immunocompetent persons are also increasingly reported. The purpose of this review is to bring attention to this emerging health problem in Portugal and Brazil and to emphasize the urgent need for increased surveillance and more comprehensive epidemiological data in both countries, where such information is scarce and seriously thwarts the adoption of proper preventive strategies and therapeutic options.

Mycobacterium sherrisii Lung Infection in a Brazilian Patient with Silicosis and a History of Pulmonary Tuberculosis

Nontuberculous mycobacteria (NTM) diseases became relevant with the emergence and spread of HIV and are also related to lung infection in non-HIV individuals with structural lung diseases. Mycobacterium sherrisii is a NTM first characterized in 2004. Only a few cases have been reported. The aim of this case report is to describe the first detailed case of infection with M. sherrisii in a patient with silicosis and history of pulmonary tuberculosis. A 50-year-old HIV-negative white male, previous smoker, with silicosis and a history of treated pulmonary tuberculosis developed a worsening of cough and expectoration pattern, and two sputum samples were positive for acid-fast bacilli. Presumptive treatment for pulmonary tuberculosis was initiated with rifampin, isoniazid, pyrazinamide, and ethambutol, but, at month 5 of treatment, despite correct medication intake and slight improvement of symptoms, sputum bacilloscopy remained positive. Sputum cultures were positive Mycobacterium sherrisii. Treatment regimen was altered to streptomycin (for 2 months), ethambutol, clarithromycin, rifabutin, and trimethoprim-sulfamethoxazole. M. sherrisii should be considered a possible etiological agent of lung infections in patients with pneumoconiosis and history of tuberculosis.