Clinical relevance of pulmonary non-tuberculous mycobacterial isolates in three reference centres in Belgium: a multicentre retrospective analysis

Abstract

Background/objectivesAssessing the clinical relevance of non-tuberculous mycobacteria (NTM) isolated from respiratory samples can be challenging. The epidemiology and pathogenicity of NTM species vary geographically. We aimed to outline the clinical relevance and associated radiological patterns of NTM species isolated in Belgium.MethodsWe performed a retrospective multicentre analysis of all patients identified from the laboratory database with > 1 respiratory sample growing NTM from January 2010 through December 2017. We collected clinical, radiological and microbiological data through medical record review and assessed clinical relevance according to ATS/IDSA criteria for NTM pulmonary disease (NTM-PD).ResultsOf the 384 unique patients, 60% were male, 56% had a smoking history and 61% had pre-existing lung disease. Mycobacterium avium complex (MAC), M. gordonae and M. xenopi were the most frequently isolated species: 53, 15 and 8% respectively. 43% of patients met ATS/IDSA criteria, of whom 28% presented with fibrocavitary disease. Weight loss, fever, nodular bronchiectatic and fibrocavitary lesions on chest CT, and a positive acid-fast bacilli (AFB) stain were significantly associated with NTM-PD. The species with the highest pathogenic potential were M. abscessus (11/12), M. malmoense (6/7) and M. intracellulare (41/64).ConclusionIn our study, MAC was the most commonly isolated NTM species, but M. abscessus and M. malmoense showed the highest probability of being clinically relevant. Clinical relevance varied not only by species but also by radiological findings on chest CT and AFB staining. Clinicians should consider these elements in their treatment decision making. Prospective data including clinical outcome are needed to provide more robust evidence.

Risk factors for nontuberculous mycobacterial pulmonary disease (NTM-PD) in Croatia

“…In the unadjusted analysis COPD was not associated with NTM-PD (OR 1.14, p=0.535). This finding contrasts with the findings of a study done on the Danish population (OR 2.15, p<0.0001), but is similar to the findings from a Belgian retrospective analysis (OR 1.00) [3,20]. Even though it is known that obstructive lung diseases (OLD), such as asthma and COPD, are risk factors for NTM-PD, it is unclear whether the association between NTM-PD and OLD is due to structural and/or functional abnormalities, medications used in the treatment of OLD, combination of these factors or some other factors.…”

Genetic Diversity of Non-Tuberculous Mycobacteria among Symptomatic TB negative Patients in Kenya

“…These findings are consistent with our study that identified species belonging to MAC (31%) (M. avium subspecies (32%), M. intracellulare (27%), M. yongonese (18%), M. parascrofulaceum (5%), M. paratuberculosis (2%), and M.timonense (2%)) as the most widely isolated NTM in Kenya. Other countries with similar findings include China [39]- [41], Russia [42], America [43], [44], various countries in Europe [45] and Africa [11], [20], [46]- [48]. The high infectivity rate of MAC species could be attributed to their seemingly abundant nature and distribution in different environmental sources such as water and soil, consequently increasing its ease of spread and infection to humans [20], [49].…”

Exploring Potential COPD Immunosuppression Pathways Causing Increased Susceptibility for MAC Infections among COPD Patients

“…The incidence of MAC infections is increasing continuously worldwide. Studies conducted in Belgium [ 13 ], Germany [ 14 , 15 ], South Korea [ 16 ], Japan [ 17 ], Brazil [ 18 ], and more showed the increase in incidence of MAC causing pulmonary disease, specifically MAC in the past 15 years. Most of the studies concluded that the recovery rate and infection rates of MACs were increasing in the past decade, with the highest prevalence in the elderly and individuals with existing respiratory predispositions [ 14 ].…”