Prevalence Of Nontuberculous Mycobacteria Disease Research Articles

NONTUBERCULOUS MYCOBACTERIA - CURRENT RISK IN BULGARIA

Background: Nontuberculous mycobacteria (NTM) are generally free-living and have a potential to cause opportunistic infection. More than 190 species of NTM have been identified (http://www.bacterio.net/mycobacterium.html), up to 60 species of them are pathogenic. The distribution is geographically specific for some species and others are cosmopolitan. Understanding their diversity has practical value for the treatment and management of NTM disease. Except for isolated reports, there is no accurate information about NTM spread among Bulgarian patients. Material and Methods: We retrospectively analysed the data on the NTM isolated from patients throughout the country for the period from January 2010 to December 2017. Identification to the species level was done by Line Probe Assay (LPA). Results: 586 NTM strains were identified. We calculated the rate of NTM isolation in Bulgaria and NTM disease incidence by applying microbiological criteria defined by the American Thoracic Society (ATS). As a result, the laboratory isolation rate amounted to 1/100 000 people for the period, and when applying only the ATS criteria, the prevalence of NTM disease was 0,23 per 100 000 people. In both cases, we reported that NTM disease incidence remains low as compared to tuberculosis, though with an increasing trend. The prevalence of NTM varied significantly between northern and southern Bulgaria, as well as between the capital and the rest of the country's regions. Conclusions: Slow growing NTM species predominate in Bulgaria but rapidly growing ones have isolation levels higher than the average for Europe and closer to that of Asian countries. Given the demographic situation in Bulgaria and the changing climatic factors, NTM infections need special attention.

The respiratory microbiome and nontuberculous mycobacteria: an emerging concern in human health.

Nontuberculous mycobacteria (NTM) are diverse microbial species encompassing commensals and pathogens with the ability to cause pulmonary disease in both immunocompetent and immunocompromised individuals. In contrast to Mycobacterium tuberculosis, which has seen a reduction in disease rates in developed countries, the incidence and prevalence of NTM disease is increasing. NTM are difficult to treat with standard antimicrobial regimens and may contain both virulence and antibiotic-resistance genes with potential for pathogenicity. With the advent of molecular techniques, it has been elucidated that these organisms do not reside in isolation and are rather part of a complex milieu of microorganisms within the host lung microbiome. Over the last decade, studies have highlighted the impact of the microbiome on host immunity, metabolism and cell-cell communication. This recognition of a broader community raises the possibility that the microbiome may disrupt the balance between infection and disease. Additionally, NTM disease progression and antimicrobial therapy may affect the healthy steady state of the host and function of the microbiome, contributing to further dysbiosis and clinical deterioration. There have been limited studies assessing how NTM may influence the relationship between microbiome and host. In this review, we highlight available studies about NTM and the microbiome, postulate on virulence mechanisms by which these microorganisms communicate and discuss implications for treatment.

Species identification and antimicrobial susceptibility testing of non-tuberculous mycobacteria isolated in Chongqing, Southwest China.

With the rapid rise in the prevalence of non-tuberculous mycobacteria (NTM) diseases across the world, the microbiological diagnosis of NTM isolates is becoming increasingly important for the diagnosis and treatment of NTM disease. In this study, the clinical presentation, species distribution and drug susceptibility of patients with NTM disease visiting the Chongqing Public Health Medical Centre during March 2016-April 2019 were retrospectively analysed. Among the 146 patients with NTM disease, eight NTM species (complex) were identified. The predominant NTM species in these patients were identified to be Mycobacterium abscessus complex (53, 36.3%), M. intracellulare (38, 26%) and M. fortuitum (17, 11.7%). In addition, two or more species were isolated from 7.5% of the patients. Pulmonary NTM disease (142, 97.3%) showed the highest prevalence among the patients. It was observed that 40.1% of the patients with pulmonary NTM disease had chronic pulmonary obstructive disease and bronchiectasis, while 22.5% had prior tuberculosis. Male patients showed more association with the conditions of cough and haemoptysis than the female patients. In an in vitro antimicrobial susceptibility testing, most of the species showed susceptibility to linezolid, amikacin and clarithromycin, while M. fortuitum exhibited low susceptibility to tobramycin. In conclusion, the prevalence of NTM disease, especially that of the pulmonary NTM disease, is common in Southwest China. Species identification and drug susceptibility testing are thus extremely important to ensure appropriate treatment regimens for patient care and management.

Pulmonary infection and colonization with nontuberculous mycobacteria, Taiwan, 2000-2012.

We analyzed samples from 13,652 patients who had respiratory cultures positive for mycobacteria in Taiwan during 2000–2012 and found that 56.9% were positive for nontuberculous mycobacteria (NTM). Whereas annual prevalence of tuberculosis decreased during the study period, prevalence of NTM disease and colonization increased, particularly among older patients and male patients.

Nontuberculous Mycobacterial Pulmonary Infections in Non-HIV Patients

Nontuberculous mycobacteria (NTM) are ubiquitous organisms with nearly 100 different species found in soil and water. The fatty-acid and wax-rich impermeable cell wall of the mycobacteria allow for adherence to solid substrates such as pipes and leaves, allowing the organism to persist despite treatment with common disinfectants. Mycobacteria can cause infection in both humans and animals. It is difficult to assess the incidence or prevalence of NTM disease due to multiple factors. Nontuberculous mycobacteria infection may be difficult to differentiate from colonization, and when NTM infection is diagnosed, it is not a reportable disease. Furthermore, some species such as Mycobacterium gordonae may be a contaminant. Nontuberculous mycobacteria infection is not a communicable disease, although health care-associated outbreaks have been reported, associated with a single facility or procedure. While the nontuberculous infection may affect other organs, the most common site is the lung, and the most common species is Mycobacterium avium complex, commonly referred to as MAC infection. An increasing occurrence of MAC has been reported, especially in certain populations such as middle-aged or elderly thin women, patients with chronic lung disease, human immunodeficiency virus infection, and cystic fibrosis. An association of NTM infection with gastroesophageal reflux disease has also been noted. The clinical presentation often includes chronic productive cough. Other less common symptoms include dyspnea and hemoptysis. With increased use of computed tomography and high-resolution computed tomography, patterns of MAC pulmonary infection have been described. Recently, the American Thoracic Society has outlined guidelines for the diagnosis and management of NTM infection. Treatment of NTM infection requires at least 3 effective drugs for a minimum of 12 months after sputum conversion to negative cultures. Surgical therapy may be considered for localized disease which has failed medical management. In this article, the clinical presentation, radiographic features, diagnostic evaluation, and management are discussed.