Significance Of Nontuberculous Mycobacteria Research Articles

Survey of Mycobacterium spp. in Eurasian Badgers (Meles meles) in Central Italy.

A survey to determine the presence of Mycobacterium spp. in the Abruzzo and Molise regions was conducted by testing samples from 124 badgers found dead or road-killed during the 2013-2021 period. Head lymph nodes were collected from all carcasses, as well as mediastinal lymph nodes from 20 of them, for bacteriological and molecular tests; tissues were inoculated onto a set of solid egg-based Lowenstein-Jensen media and in a liquid culture system (BACTEC) and were analyzed by polymerase chain reactions (PCRs). Organs and lymph nodes from 31 carcasses were collected for histological tests. During post-mortem examinations, macroscopic lesions consistent with a Mycobacterium tuberculosis complex (MTBC) and with nontuberculous mycobacteria (NTM) infections were not detected. Mycobacteria were isolated from four animals (3.22%). M. avium subsp. avium was isolated by head lymph nodes from two badgers (1.61%), M. avium subsp. paratuberculosis (0.80%) from one, and Mycobacterium spp. from another (0.80%). The significance of nontuberculous mycobacteria (NTM) in wildlife hosts in the absence of clinical signs and gross pathology has yet to be assessed. The most critical aspect came from isolates belonging to the Mycobacterium avium complex infection in wildlife due to the possible interference with tuberculin skin tests in cattle.

The clinical significance of nontuberculous mycobacteria at King Abdulaziz Medical City-Western Region from 2013 to 2020

The clinical significance of nontuberculous mycobacteria at King Abdulaziz Medical City-Western Region from 2013 to 2020

Clinical course and significance of nontuberculous mycobacteria and its subtypes in cystic fibrosis

BackgroundNontuberculous mycobacteria (NTM) infections in patients with cystic fibrosis (CF) is increasing globally. However, the related epidemiology, comorbidities, and clinical impact of NTM infection remains unclear in the progress of CF lung disease and patient survival.MethodsWe performed a retrospective, case-control, cohort study (10 years), comparing NTM culture-positive CF patients (N = 28) to matched controls (N = 26). NTM positive patients were divided in to two groups of slow-growing (N = 17) and rapid- growing NTM (N = 8). Three patients were positive for both slow and rapid NTM. For independent group comparisons, a non-parametric Mann-Whitney test (Kruskal-Wallis test for more than two groups) was used to compare the continuous variables, and a Fisher’s exact test was used for the categorical variables. Paired comparisons were performed using a Wilcoxon signed-rank test.ResultsThe prevalence of NTM isolation was 8%. The age at CF diagnosis was significantly lower in the slow-growing NTM group compared to the rapidly growing NTM group (P = 0.04). The median percent predicted forced expiratory flow of 25% − 75% (FEF25–75) was significantly higher before NTM acquisition in slow-growing (P = 0.013) and rapidly growing NTM group (P = 0.028). The slow-growing NTM group received significantly more penicillin/beta lactamase (P = 0.010) and rifampin (P = 0.042) following isolation. Macrolide use was significantly higher after isolation in both the slow-growing NTM (P = 0.018) and rapidly growing NTM groups (P = 0.042).ConclusionsAn earlier CF diagnosis was associated with a higher isolation of slow-growing NTM and greater antimicrobial use after infection. NTM acquisition is associated with a worsening of FEF25–75. Thus, both the early diagnosis and treatment of an NTM infection in patients with CF may positively impact lung function.

Clinical significance of nontuberculous mycobacteria isolated from respiratory specimens

Objective To determine the clinical significance of nontuberculous mycobacteria (NTM) isolated from respiratory specimens. Methods Clinical data of patients with NTM strains isolated from the respiratory tract between January 2014 and February 2017 were retrospectively analyzed. Clinical significance of NTM isolated strains was evaluated based on diagnostic criteria of NTM pulmonary diseases from American Thoracic Society (ATS). Quantitative data of two groups were analyzed by independent t test. Categorical data were analyzed by Pearson χ2 test or Fisher exact test. Results Totally 352 NTM strains from 257 patients had been isolated between January 2014 and February 2017. Among 15 identified NTM species, M. intracellular (51.7%, 182/352), M. abscessus (25.6%, 90/352), and M. avium (10.8%, 38/352) were predominant. Of the 157 patients with full clinical data involved in the analysis, 58 (36.9%) patients were determined to have definite disease, and 34 patients (21.7%) were designated as probable disease candidates, and 16 (10.2%) patients were regarded as uncertain disease, and 49(31.2%) patients were diagnosed as unlikely disease. The age of 58 patients with definite disease was (63.9±12.7) years, and 48.3% (28/58) were female. M. intracellulare (55.2%, 32/58) was the main cause of pulmonary NTM disease, followed by M. abscessus (25.9%, 15/58) and M. avium (12.1%, 7/58), while other NTM species only accounted for 6.8% (4/58). Definite cases with M. intracellulare, M. abscessus, M. avium, M. kansasii, M. marseillense, and M. columbia accounted for 35.2% (32/91), 57.7% (15/26), 7/15, 2/3, 1/3 and 1/2, respectively, among patients with corresponding isolations, while patients with other species of isolation did not meet the diagnostic criteria. Patients with clinical significant isolation of NTM were older than those without clinical significance (χ2=3.603, P=0.000), and proportion of anti-acid staining positivity of patients with clinical significance was higher than that of patients without clinical significance (χ2=18.815, P=0.000). The proportion of M. abscessus in patients with clinical significance was higher than that in patients without clinical significance (χ2=6.313, P=0.012). However, there was no significant difference between the two groups in the isolation of M. Gordon (Fisher exact test, P=0.028). The proportion of M. abscessus lung disease in women was 11/15, which was higher than that of M. intracellulare lung disease (41.5%, 17/41), and the difference between the two groups was statistically significant (χ2=4.462, P=0.035). There was no significant difference of clinical symptoms and underlying diseases in NTM lung disease among different groups (all P>0.05). In these patients with definite disease, 39.7% (23/58) of them manifested the upper lobe cavitary form, 53.4% (31/58) exhibited nodular bronchiectatic form, and only 6.9% (4/58) exhibited unclassified form. The upper lobe cavitary form (43.8%, 14/32) and the nodular bronchiectatic form (53.1%, 17/32) dominated in patients with M. intracellulare lung disease. M. abscessus lung disease was dominated by the nodular bronchiectatic form (11/15) while the upper lobe cavitary form only accounts for 3/15. There was no significant difference of image characteristics between NTM lung disease and other different groups (all P>0.05). Conclusions 36.9% of the patients with NTM isolates met the ATS diagnostic criteria for NTM lung disease. Different species have different clinical significance. M. intracellulare and M. abscessus are the most predominant NTM isolated species that cause NTM lung disease. Majority of patients manifest as the upper lobe cavitary form, followed by the nodular bronchiectatic form. Key words: Respiratory; Nontuberculous mycobacteria; Clinical relevance; Clinical significance

Detection of Mycobacteria by Culture and DNA-Based Methods in Animal-Derived Food Products Purchased at Spanish Supermarkets.

Mycobacteria include obligate and opportunistic pathogens that cause significant human and animal disease. The burden of tuberculosis has been largely reduced in developed territories but remains a huge problem worldwide. The significance of nontuberculous mycobacteria is growing considerably, especially in developed regions with higher life expectancy and more therapy-related immunosuppressed individuals. Due to their robustness mycobacteria can contaminate animal products by direct transmission from infected individuals or by environmental contamination during processing. The situation at market level is poorly known. Most studies analyzing commercially available foods are limited to a small or local scale and mainly focused on a particular mycobacterial species. There is a need to investigate if animal products that have passed the established controls to be for sale at main supermarkets could represent a route of contact with any mycobacteria. Thus, our goal was to study the prevalence of mycobacteria in these foods to assess if this could represent a source of human exposure. Five stores from the main supermarket chains in Spain were selected. 138 dairy and 119 meat products were purchased. All were processed using culture and multiplex real-time PCR methods. Additional molecular methods were used to specifically identify any positive result. Mycobacterium avium subsp. hominissuis (2), M. avium subsp. avium (1), and M. fortuitum (1) were isolated from powdered infant formula and ground beef, chicken sausage, and mortadella cold cut, respectively. Mycobacterial DNA (M. avium, M. tuberculosis complex and other nontuberculous mycobacteria) was detected in 15% of dairy products and 2% of meat products. These results show that the prevalence of viable mycobacteria in foods of animal origin obtained at the supermarket was not substantial although a considerable proportion of them contained mycobacterial DNA. Contact with mycobacteria through this route could be ensured over time. Further investigation is necessary to determine the real impact of foodborne mycobacterial exposure on human health and identify critical points in the food production system to enable setting up more stringent control measures.

Nontuberculous mycobacteria among pulmonary tuberculosis patients: a retrospective Belgian multicenter study

Objectives: Currently, there are no European data about the frequency and clinical significance of nontuberculous mycobacteria (NTM) grown from respiratory samples during the treatment of tuberculosis (TB). We determined the frequency and clinical significance of NTM isolated before or during pulmonary tuberculosis treatment in Belgian laboratories.Methods: We conducted a nationwide retrospective multicenter cohort study on the co-isolation of TB and NTM in Belgium. Starting from laboratory data between 2006 and 2013, possible TB–NTM co-isolations were searched for.Results: A total of 2569 unique culture-positive pulmonary tuberculosis cases were included in the study. Only 35 (1.4%) of these TB cases had an NTM co-isolated, and two of these 35 fulfilled the ATS criteria for NTM lung disease.Conclusion: A very low prevalence of 1.4% NTM co-isolations was found in Belgian patients with culture-proven pulmonary TB.

141 A retrospective review of non-tuberculous mycobacteria in paediatric cystic fibrosis patients at a regional centre

Non-tuberculous mycobacteria (NTM) are increasingly isolated from CF patients. We carried out a retrospective review of respiratory specimens from paediatric patients at a regional CF centre to assess the possible significance of NTM. Samples from 158 patients were reviewed. 7 patients (4%) were identified as having NTM isolated from at least one clinical specimen (4 male, 3 female, age range when NTM first isolated 7−12 yrs). The sample type of first isolation was a bronchoalveolar lavage (BAL) in 2 cases, sputum in 3 cases and cough swab in 2 cases. The NTM isolated were M avium complex (MAC) (n = 3), M. chelonae (n = 3) and M abscessus (n = 1). Initial NTM positive samples were isolated from 1 patient in 2007, 3 patients in 2008, 2 in 2009 and 1 in 2010. None of the initial positive samples (BALs or sputums) were smear positive, although one patient with an initial smear negative, culture positive sputum was smear positive on a follow-up BAL. All isolates were initially sensitive in vitro to azithromycin and clarithromycin. Only one patient was treated for NTM infection. MAC was isolated from a BAL following deterioration in respiratory symptoms; Burkholderia vietnamiensis was also isolated and he received dual treatment with ciprofloxacin and azithromycin and was showing an improvement in respiratory function at 3 months. All patients had other potential pathogens isolated with NTM, including Aspergillus sp. (n = 4). Three patients received steroids for treatment of ABPA prior to isolation of NTM. Identifying whether NTM represents colonisation or infection is difficult and may be complicated by other organisms; trial of therapy with assessment of response may be indicated.

Nontuberculous mycobacteria isolated during the treatment of pulmonary tuberculosis

The significance of nontuberculous mycobacteria (NTM) isolated from a patient during therapy for pulmonary tuberculosis (TB) is uncertain. We investigated the frequency and clinical significance of NTM isolated from patients receiving anti-TB treatment. We conducted a retrospective cohort study of all patients with culture-confirmed pulmonary TB, and identified patients with respiratory cultures positive for NTM during therapy for pulmonary TB. From January 2003 to December 2005, 958 patients were diagnosed with culture-confirmed pulmonary TB. NTM were isolated from 113 specimens in 68 (7.1%) patients during anti-TB treatment. The most frequently isolated NTM species were Mycobacterium abscessus (n=35, 31%), Mycobacterium fortuitum (n=17, 15%), Mycobacterium avium complex (n=9, 8%), and Mycobacterium gordonae (n=9, 8%). Forty-eight (71%) patients had only one positive culture, while 20 (29%) had two or more positive cultures for NTM. Only two (3%) patients who had two or more positive culture after anti-TB treatment showed the same NTM species, which were M. abscessus. The isolation of NTM in patients with pulmonary TB is not uncommon during anti-TB treatment. However, this is likely the result of colonization, a transient infection, or specimen contamination. The co-existence of pulmonary TB and NTM lung disease may be rare but should be considered in patients with relatively virulent NTM species such as M. abscessus.

Distribution and Clinical Significance of Nontuberculous Mycobacteria Identified by High Performance Liquid Chromatography in Clinical Specimens

Background: Infections caused by nontuberculous mycobacteria (NTM) are significantly increasing over the last decade. Due to the uncertainty in the clinical significance of these organisms, their effective diagnosis and treatment has been challenging. The purpose of this study was to investigate the distribution and clinical significance of NTM in clinical specimens. Methods: Acid-fast culture positive 3,107 clinical specimens were identified by mycolic acid analysis using high performance liquid chromatography (HPLC.) The HPLC patterns of 384 NTM strains were compared with those of standard mycobacterium species. Clinical significance of NTM was investigated by a retrospective study including acid-fast stain and culture, medical history, symptoms and signs, radiological and other laboratory findings, pathologic findings, response to treatment, and follow-up study, and was confirmed according to the guideline of American Thoracic Society. Results: Among the 3,107 Mycobacterium-positive specimens, 384 (12.4%) were found to be positive for NTM. Of these, 367 (95.6%) were successfully identified by HPLC as 19 different species, each of which comprising 0.3% to 15.9% of the total NTM, Studies on the pathogenic role of NTM showed that 0∼79.6% of each species or 0∼100% of isolates from each specimen could be considered clinically significant. Conclusion: HPLC method is highly discriminative for the identification of NTM in clinical specimens. When NTM is isolated from clinical specimens in the Ulsan area, the findings from this study could serve as a database on which to determine its clinical significance depending on species type and also specimen type. (Korean J Clin Microbiol 2008;11:34-42)

Nontuberculous Mycobacteria in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are widely distributed in our modern environment. Therefore, it is not surprising that these organisms are commonly present in sputum from cystic fibrosis (CF) patients. In the setting of CF lung disease, the significance of NTM in respiratory secretions is a major diagnostic challenge. The usual signs, symptoms, and radiographic features of NTM disease are also characteristic of CF lung disease; thus it is difficult to determine whether the NTM are a saprophytic contaminant or an active pathogen. Although many CF patients appear to tolerate the presence of the NTM without clear evidence of disease, some suffer accelerated progression of lung disease that cannot be solely attributed to CF and appear to benefit from antimycobacterial treatment. Standard CF care should be reemphasized in patients with NTM infection, especially aggressive bronchial hygiene. Specific guidelines for antimycobacterial therapy in CF patients have not been determined, and potential complications of treatment are significant. Hence, patients offered antimycobacterial treatment must be selected carefully. An initial approach to treatment of CF patients is based on guidelines developed for the general population.

Nontuberculous mycobacteria.

The nontuberculous mycobacteria (NTM), especially Mycobacterium avium complex, are being recognized with increasing frequency as clinical pathogens, not only as a cause of disseminated disease in patients with AIDS but also as a cause of chronic lung disease in patients without AIDS. These infections have traditionally been difficult and frustrating to treat; however, the introduction of new agents, such as clarithromycin, azithromycin, and rifabutin, has significantly improved outcome for patients with some NTM infections. The new therapeutic regimens can be associated with severe toxicities and drug interactions that dictate the need for careful monitoring of patients undergoing treatment for M. avium complex disease. Clinicians will be called on with increasing frequency to determine the significance of NTM isolated from their patients. This determination will require knowledge about the pathogenicity and the appropriate therapy of a variety of NTM species.