Nontuberculous mycobacteria in Denmark, incidence and clinical importance during the last quarter-century

Nontuberculous mycobacterial infection in Wisconsin children and adolescents

Background

The epidemiology of nontuberculous mycobacteria (NTM) infections in the pediatric population is not well described. We estimated the incidence of NTM infection in Wisconsin children and adolescents, and the frequency and type of infection caused by different NTM pathogens. Associations between NTM infection and race/ethnicity and social disadvantage, respectively, were also investigated.

Methods

This retrospective cohort study evaluated reports of NTM infection in Wisconsin residents under 18 years of age submitted to a state-wide database between 2011 and 2018. Demographics of the cohort, including a social disadvantage score (Area Deprivation Index (ADI)), are described. Specimen type and NTM species are enumerated for reported isolates.

Results

There were 224 NTM isolates from 212 children and adolescents. Median age of participants was 3 years; 55 % were female. Cumulative incidence did not vary significantly between the larger racial groups or for the various ADI score groups. Compared to white participants (157), there was a significantly lower cumulative incidence of NTM infection in multiracial individuals (2). Mycobacterium avium complex (MAC) was the most frequently isolated organism (69 %). The majority of isolates (52 %) were from skin and soft tissue, which included lymph node specimens. Annual incidence did not vary significantly over the study period.

Conclusions

The epidemiology of pediatric NTM infections in this cohort is consistent with previous pediatric reports of higher rate of infection in females and predominance of skin and soft tissue infections. Disparities in disease burden across racial/ethnic and socio-economic groups were not demonstrated, but these factors should be further explored in larger pediatric studies of diverse U.S. populations.

Nontuberculous Mycobacteria in Portugal: Trends from the last decade

INTRODUCTION AND OBJECTIVES

Nontuberculous mycobacteria (NTM) are opportunistic human pathogens found in the environment. The transmission seems to be associated with inhalation of aerosol droplets, ingestion or trauma events. Recent studies indicate that NTM disease is increasing worldwide, however, the true clinical impact of NTM infections is difficult to determine due to challenges in discriminating between disease and colonization as they are ubiquitous in the environment. In addition, understanding the epidemiology of NTM is difficult and has not yet been established. In this work, we used a country NTM representative collection from the National Reference Laboratory for Tuberculosis (NRL-TB) of the National Institute of Health (INSA), to characterize the circulation trends of NTM species in Portugal and the most affected regions, contributing to a better understanding of the NTM epidemiology.

MATERIAL AND METHODS

We conducted a nationwide retrospective study where all individuals with positive NTM cultures at the NRL-TB of the INSA from 2014 to December 2020 were included. Positive cultures were identified using GenoType Mycobacterium CM/AS® (Hain Lifescience) according to manufacturer's instructions, or hsp65 DNA sequencing as previously described. Social-demographic data from patients were also analyzed and patients classified into 3 groups according only to microbiological data, "definite NTM disease", "NTM colonization" and, "possible NTM disease".

RESULTS

In the period 2014-2020, the NRL-TB performed 50397 cultures. Among these, 1118 cultures were NTM positive retrieved from 944. Most of our cases were in patients whose mean age was 64±15.9 years, and no significant differences between gender was observed, although more frequent in male patients. Overall, from the 944 cases, we were able to identified 93 "definite NTM disease" cases and 79 "possible NTM disease". Mycobacterium avium complex (MAC) (40,8%), Mycobacterium abscessus-chelonae complex (MABC) (9,6%) and Mycobacterium fortuitum (6,3%) were responsible for most of the infections. The geographical distribution of NTM cases varied significantly and was possible to observe that was independent of population density. The region were most cases occurred was Lisbon Metropolitan Area (31,9%), followed by North (25,3%) and Centre (24,4%), however North region has the highest number of "definite NTM disease" cases (n=33).

CONCLUSIONS

This is the first national wide epidemiological study on this subject, contributing to a better understanding of NTM dynamics in Portugal. MAC was the NTM species responsible for the majority of infections and, LMA the region with the highest number of cases. It was also possible to conclude that the number of NTM isolates is independent of the demography of the region.

Nontuberculous mycobacterial disease in children: A systematic review and meta-analysis

Background

The prevalence of nontuberculous mycobacterial (NTM) disease in children is increasing worldwide. The clinical manifestations of pediatric NTM patients are significantly different from those of adult patients, but the knowledge of the disease is generally poor.

Methods

English databases (PubMed, Web of Science, Embase, BIOSIS) and Chinese databases (CNKI, Wanfan, VIP) were searched on October 15th, 2022. All the articles of cross-sectional and cohort studies reporting the species composition and lesion site of the NTM disease in children using well-recognized NTM species identification methods were taken into account. Using a random effects model, we assessed the disease lesion sites and the prevalence of different NTM species in pediatric NTM disease. Sources of heterogeneity were analyzed using Cochran's Q and the I2 statistic. All analyses were performed using CMA V3.0.

Results

The prevalence rates of NTM disease in children ranged between 0.6 and 5.36/100,000 in different countries, and Europe reported the highest prevalence rate. The most common clinical lesion site was lymph node, accounting for 71.1 % (55.0 %-83.2 %), followed by lung (19.3 %, 9.8%-34.4 %）and then skin and soft tissue (16.6 %,13.5%-20.3 %). Mycobacterium avium complex (MAC) was the most isolated NTM pathogen in children, accounting for 54.9 % (39.4%-69.6 %). Inconsistent with adult patients, Mycobacterium avium accounted for a dominant proportion in MAC than Mycobacterium intracellulare.

Conclusions

The lymph node was the most affected organ in pediatric NTM disease, while Mycobacterium avium was the most isolated pathogenic species in children.

Drugs for treating infections caused by non-tubercular mycobacteria: a narrative review from the study group on mycobacteria of the Italian Society of Infectious Diseases and Tropical Medicine

BACKGROUND

Non-tuberculous mycobacteria (NTM) are generally free-living organism, widely distributed in the environment, with sporadic potential to infect. In recent years, there has been a significant increase in the global incidence of NTM-related disease, spanning across all continents and an increased mortality after the diagnosis has been reported. The decisions on whether to treat or not and which drugs to use are complex and require a multidisciplinary approach as well as patients' involvement in the decision process.

METHODS AND RESULTS

This review aims at describing the drugs used for treating NTM-associated diseases emphasizing the efficacy, tolerability, optimization strategies as well as possible drugs that might be used in case of intolerance or resistance. We also reviewed data on newer compounds highlighting the lack of randomised clinical trials for many drugs but also encouraging preliminary data for others. We also focused on non-pharmacological interventions that need to be adopted during care of individuals with NTM-associated diseases CONCLUSIONS: Despite insufficient efficacy and poor tolerability this review emphasizes the improvement in patients' care and the needs for future studies in the field of anti-NTM treatments.

Nationwide Increasing Incidence of Nontuberculous Mycobacterial Diseases Among Adults in Denmark: Eighteen Years of Follow-Up

BACKGROUND

The epidemiology of nontuberculous mycobacteria (NTM) infections is not well described. In this study, we determine the incidence and prevalence of NTM infections and focus on social risk factors. In addition, we describe people with pulmonary and extrapulmonary NTM.

RESEARCH QUESTION

What are the incidence and prevalence of NTM, and what are the characteristics of the affected patients?

STUDY DESIGN AND METHODS

This is a nationwide retrospective register-based cohort study in Denmark. Adult patients in the Danish national registers who received a diagnosis of NTM disease from 2000 to 2017 were classified as having either pulmonary or extrapulmonary NTM disease.

RESULTS

We identified 1,146 adults with an NTM diagnosis. Of these, 661 patients had pulmonary NTM, of whom 50.4% were male, whereas 485 had extrapulmonary NTM, of whom 59.6% were male. The median age (interquartile range) was 66 (18) years and 57 (32) years, respectively. The yearly incidence rate per 100,000 increased between 2000 and 2017 for both pulmonary NTM (0.4 to 1.3) and extrapulmonary NTM (0.3 to 0.6). The annual prevalence per 100,000 increased from 0.4 to 3.5 for pulmonary NTM and from 0.3 to 1.0 for extrapulmonary NTM. The incidence rate increased with age. The incidence of pulmonary NTM was highest among those who were 70 years of age or older (19.3 per 100,000). Compared with patients with pulmonary NTM, patients with extrapulmonary NTM were more likely to be employed and had a higher educational level.

INTERPRETATION

The prevalence of NTM disease in Denmark increased between 2000 and 2017. Patients with pulmonary NTM and patients with extrapulmonary NTM represent two distinct groups that differ in age, sex, education, and employment status. Increased suspicion of pulmonary NTM disease is warranted in the elderly after exclusion of more common lung infections.

Identification and Antimicrobial Susceptibilities for Patients with Non-tuberculous Mycobacteria Infection in Jeju Island: Single-Center Retrospective Study

BACKGROUND

The distribution of species and characteristics of non-tuberculous mycobacteria (NTM) differ, and surveillance data for changes in antimicrobial susceptibilities of NTM is insufficient. This study analyzed the changes in antimicrobial susceptibility trends across NTM species and assessed the appropriateness of empirical antimicrobial drugs for NTM.

MATERIALS AND METHODS

We retrospectively analyzed the clinical characteristics, including demographics, distribution of NTM species, antimicrobial drug susceptibilities, and outcomes, at a teaching hospital in Jeju Island from 2009 - 2022.

RESULTS

Overall, 342 patients were included in the analysis; 93.0% were classified into the pulmonary group (PG) and 7.0% into the extrapulmonary group (EPG). The isolation rate of Mycobacterium avium was significantly higher in PG (36.8% vs. 0%, P = 0.001), while that of Mycobacterium fortuitum was significantly higher in EPG (4.5% vs. 31.3%, P = 0.001). The antimicrobial susceptibility rate is higher against clarithromycin (89.9%) and amikacin (83.3%) and lower against rifampin (54.7%) and ethambutol (28.1%). The susceptibility rate to clarithromycin was over 80%, but those to rifampin and ethambutol showed decreasing annual trends. Of the 162 patients who received empirical antimicrobial therapy, actual antimicrobial susceptibility rates were high (90.1%) using empirical macrolide, and relatively low using ethambutol and rifampin (28.0% and 58.8%, respectively).

CONCLUSION

This is the first study of analysis of the distribution, baseline characteristics, and antimicrobial susceptibility of isolated NTM species in pulmonary and extrapulmonary patients in Jeju Island over 10 years. Policies that continuously monitor changes in susceptibility rate are required to ensure effective treatment strategies.

Extrapulmonary nontuberculous mycobacterial infections: a guide for the general physician

Non-tuberculous mycobacteria (NTM) infections predominantly present as pulmonary disease. Although relatively rare, 20-30 % originate from extrapulmonary sites resulting in a wide range of clinical syndromes. Immunocompromised individuals are particularly susceptible. Clinical manifestations include skin and soft-tissue infections, lymphadenitis, musculoskeletal infections and disseminated disease. Diagnosing extrapulmonary NTM is challenging, and management is complex, often involving multiple radiological and microbiological investigations, long courses of combination antibiotic regimens and may require adjuvant surgical interventions. We highlight both the importance of involving NTM experts at an early stage and the role of a multidisciplinary approach in the diagnosis and management of these infections.

Global Epidemiology of Nontuberculous Mycobacterial Pulmonary Disease: A Review

Nontuberculous mycobacterial (NTM) isolation and pulmonary disease (NTM-PD) have continued to increase in most regions of the world, driven mainly by Mycobacterium avium. Single-center studies also support increasing trends as well as a persistent burden of undiagnosed NTM among persons suspected of having tuberculosis (TB), in countries with moderate-to-high TB prevalence. Cumulative exposure to water and soil presents an increased risk to susceptible hosts, and trace metals in water supply are recently recognized risk factors. Establishing standard case definitions for subnational and national surveillance systems with mandatory notification of NTM-PD are needed to allow comparisons within and across countries and regions.

Nontuberculous Mycobacterial Infection in Wisconsin Adults and Its Relationship to Race and Social Disadvantage

Rationale: Population-based data on the epidemiology of nontuberculosis mycobacterial (NTM) infections are limited, particularly with respect to variation in NTM infection among racial groups and socioeconomic strata. Wisconsin is one of a handful of states where mycobacterial disease is notifiable, allowing large, population-based analyses of the epidemiology of NTM infection in this state. Objectives: To estimate the incidence of NTM infection in Wisconsin adults, describe the geographic distribution of NTM infection across the state, identify the frequency and type of infection caused by different NTM species, and investigate associations between NTM infection and demographics and socioeconomic status. Methods: We conducted a retrospective cohort study using laboratory reports of all NTM isolates from Wisconsin residents submitted to the Wisconsin Electronic Disease Surveillance System from 2011 to 2018. For the analyses of NTM frequency, multiple reports from the same individual were enumerated as separate isolates when nonidentical, collected from different sites or collected more than one year apart. Results: A total of 8,135 NTM isolates from 6,811 adults were analyzed. Mycobacterium avium complex accounted for 76.4% of respiratory isolates. The M. chelonae-abscessus group was the most common species isolated from skin and soft tissue. The annual incidence of NTM infection was stable over the study period (from 22.1 per 100,000 to 22.4 per 100,000). The cumulative incidence of NTM infection among Black (224 per 100,000) and Asian (244 per 100,000) individuals was significantly higher compared with that among their White counterparts (97 per 100,000). Total NTM infections were significantly more frequent (P < 0.001) in individuals from disadvantaged neighborhoods, and racial disparities in the incidence of NTM infection generally remained consistent when stratified by measures of neighborhood disadvantage. Conclusions: More than 90% of NTM infections were from respiratory sites, with the vast majority caused by M. avium complex. Rapidly growing mycobacteria predominated as skin and soft tissue pathogens and were important minor respiratory pathogens. We found a stable annual incidence of NTM infection in Wisconsin between 2011 and 2018. NTM infection occurred more frequently in non-White racial groups and in individuals experiencing social disadvantage, suggesting that NTM disease may be more frequent in these groups as well.

Trends from the Last Decade with Nontuberculous Mycobacteria Lung Disease (NTM-LD): Clinicians' Perspectives in Regional Center of Pulmonology in Bydgoszcz, Poland

BACKGROUND

Nontuberculous mycobacteria (NTM) are the cause of chronic lung disease called NTM lung disease (NTM-LD). There are about 180 known species of NTM. Nowadays the number of NTM-LD is increasing.

OBJECTIVE

To evaluate the clinical significance of NTM isolated from specimens and assess the frequency and clinical relevance of isolation of NTM in the Regional Center of Pulmonology in Bydgoszcz, hospital of Northern Poland.

DESIGN

Clinical, radiological, and microbiological data were collected from all patients from whom NTM was isolated between 2013 and 2022. Data were reviewed retrospectively. Diagnostic criteria for NTM-LD published by the American Thoracic Society (ATS) were used to determine clinical relevance.

MATERIAL AND METHODS

The study comprised 81,985 clinical specimens submitted for mycobacterial culture in the Department of Microbiology at the Regional Center of Pulmonology in Bydgoszcz between 2013 and 2022. Clinical specimens were processed according to the standard procedure in mycobacteria laboratories in Poland. NTM strains were identified using analysis of mycolic acids by chromatography as well as GenoType NTM-DR, GenoType Mycobacterium AS, and GenoType Mycobacterium CM.

RESULTS

There were 395 patients with NTM strains between 2013 and 2022. Out of them, 149 cases met the diagnostic criteria of NTM-LD and were classified as definite cases. M. kansasii (n = 77) was the most common species in the group (51.68%), followed by M. avium complex (n = 46). Patients with NTM-LD were 22-88 years old (median age was 60 years). There were 81 men and 68 women. The most common symptoms were cough, hemoptysis, and fever. Radiological X-ray images were dominated by infiltrative lesions in the upper and middle lobe of the right lung with cavities; the changes were in the upper lobe of the left lung and on both sides of the chest. They were smokers in 61%. The most common concomitant diseases were chronic obstructive pulmonary disease (COPD), diabetes mellitus, pulmonary carcinoma, and human immunodeficiency virus (HIV) infection, and other immunodeficiencies. The most common treatment was isoniazid, ethambutol, rifampicin, and ofloxacin for 18 months with a minimum of 12 months of culture negativity.

CONCLUSIONS

NTM-LD infections are present with other pulmonary illnesses and extrapulmonary diseases and may be connected to primary immunologic deficiencies. These diseases concern patients of all ages and have various clinical manifestations. M. kansasii and MAC are the most prevalent NTM isolates among respiratory samples in Northern Poland. In addition, an increase in MAC and a decrease in M. kansasii both in cultivation and the cause of NTM-LD were reported.

Disseminated Mycobacterium genavense infection in a patient with a history of sarcoidosis

We present a case of Mycobacterium genavense infection in a man in his 60s with a history of sarcoidosis, treated for 24 years with systemic corticosteroids and later methotrexate as monotherapy. He presented with low grade fever, dyspnoea and right-sided thoracic pain and was admitted due to a treatment-refractory infection. After a prolonged period of symptoms and diagnostics, acid-fast bacilli were demonstrated in pleural fluid and PCR revealed M. genavense The patient was treated with intravenous amikacin, peroral azithromycin, rifampicin and ethambutol for a total of 18 months, with a good clinical and radiological treatment response. Infection with M. genavense is rare in HIV-negative immunocompromised hosts. Diagnosing and treating mycobacterial infections, especially for more rare species, remains a challenge as clinical evidence is sparse. Nonetheless, the disease-causing infection must be considered in symptomatic and immunocompromised patients.

Risk Factors for Nontuberculous Mycobacteria Infections in Solid Organ Transplant Recipients: A Multinational Case-Control Study

BACKGROUND

Risk factors for nontuberculous mycobacteria (NTM) infections after solid organ transplant (SOT) are not well characterized. Here we aimed to describe these factors.

METHODS

Retrospective, multinational, 1:2 matched case-control study that included SOT recipients ≥12 years old diagnosed with NTM infection from 1 January 2008 to 31 December 2018. Controls were matched on transplanted organ, NTM treatment center, and post-transplant survival greater than or equal to the time to NTM diagnosis. Logistic regression on matched pairs was used to assess associations between risk factors and NTM infections.

RESULTS

Analyses included 85 cases and 169 controls (59% male, 88% White, median age at time of SOT of 54 years [interquartile range {IQR} 40-62]). NTM infection occurred in kidney (42%), lung (35%), heart and liver (11% each), and pancreas transplant recipients (1%). Median time from transplant to infection was 21.6 months (IQR 5.3-55.2). Most underlying comorbidities were evenly distributed between groups; however, cases were older at the time of NTM diagnosis, more frequently on systemic corticosteroids and had a lower lymphocyte count (all P < .05). In the multivariable model, older age at transplant (adjusted odds ratio [aOR] 1.04; 95 confidence interval [CI], 1.01-1.07), hospital admission within 90 days (aOR, 3.14; 95% CI, 1.41-6.98), receipt of antifungals (aOR, 5.35; 95% CI, 1.7-16.91), and lymphocyte-specific antibodies (aOR, 7.73; 95% CI, 1.07-56.14), were associated with NTM infection.

CONCLUSIONS

Risk of NTM infection in SOT recipients was associated with older age at SOT, prior hospital admission, receipt of antifungals or lymphocyte-specific antibodies. NTM infection should be considered in SOT patients with these risk factors.

Global trends of pulmonary infections with nontuberculous mycobacteria: a systematic review

OBJECTIVES

To describe the global trends of pulmonary nontuberculous mycobacteria (NTM) infection and disease.

METHODS

A systematic review of studies including culture-based NTM data over time. Studies reporting on pulmonary NTM infection and/or disease were included. Information on the use of guideline-based criteria for disease were collected, in which, infection is defined as the absence of symptoms and radiological findings compatible with NTM pulmonary disease. The trends of change for incidence/prevalence were evaluated using linear regressions, and the corresponding pooled estimates were calculated.

RESULTS

Most studies reported increasing pulmonary NTM infection (82.1%) and disease (66.7%) trends. The overall annual rate of change for NTM infection and disease per 100,000 persons/year was 4.0% (95% confidence interval [CI]: 3.2-4.8) and 4.1% (95% CI: 3.2-5.0), respectively. For absolute numbers of NTM infection and disease, the overall annual change was 2.0 (95% CI: 1.6-2.3) and 0.5 (95% CI: 0.3-0.7), respectively. An increasing trend was also seen for Mycobacterium avium complex infection (n = 15/19, 78.9%) and disease (n = 10/12, 83.9%) and for Mycobacterium abscessus complex (n = 15/23, 65.2%) infection (n = 11/17, 64.7%) but less so for disease (n = 2/8, 25.0%).

CONCLUSION

Our data indicate an overall increase in NTM worldwide for both infection and disease. The explanation to this phenomenon warrants further investigation.

Clinically refined epidemiology of nontuberculous mycobacterial pulmonary disease in South Korea: overestimation when relying only on diagnostic codes

BACKGROUND

There have been reports of increases in the incidence and prevalence of nontuberculous mycobacterial pulmonary disease (NTM-PD) in several countries, but no studies have analyzed claims data using laboratory tests. This study aimed to estimate the nationwide epidemiology and medical treatments of NTM-PD according to laboratory tests run in Korea.

METHODS

Using claims data from the Health Insurance Review and Assessment Service, we analyzed patients with nontuberculous mycobacterium (ICD-10: A31) who were diagnosed from Jan 2007 to Jun 2019. The incidence and prevalence of NTM-PD and whether related laboratory tests were performed were analyzed. Diagnostic code-based NTM-PD patients were defined as patients who had NTM as a diagnosis on at least 2 occasions within 180 days. Clinically refined NTM-PD patients were defined as those excluding hospital-diagnosed patients with acid-fast bacilli (AFB) culture rates less than 5%. Laboratory tests included AFB smears, AFB culture, NTM identification, and drug susceptibility tests (DSTs).

RESULTS

A total of 60,071 diagnostic code-based NTM-PD patients were evaluated. Clinically refined NTM-PD included 45,321 patients, excluding 14,750 (24.6%) patients diagnosed in hospitals with low AFB culture rates. The annual incidence per 100,000 population increased from 2.9 cases in 2008 to 12.3 cases in 2018. The annual prevalence per 100,000 population increased from 5.3 cases in 2008 to 41.7 cases in 2018. After removing outliers according to the AFB culture rate, a significant decrease in incidence was observed in women younger than 50 years. Among patients with clinically refined NTM-PD, the test rates for AFB culture, NTM identification, and DST were 84.3%, 59.1%, and 40.4%, respectively. From the outpatient clinic, 17,977 (39.7%) patients were prescribed drugs related to NTM treatment, with a median number of prescriptions of 7 (interquartile range (IQR) 3-11) and a median duration from the diagnosis to end of treatment of 330 (IQR 118-578) days.

CONCLUSIONS

Although the incidence and prevalence of NTM-PD are on the rise, the recent surge in women 50 years of age is overestimated in patients not adequately tested. In claim-based studies, there may be limitations in estimating the epidemiological data with only the diagnostic codes.

Cavitating pulmonary lung lesions with more than one microbiological aetiology

Non-tuberculous mycobacteria (NTM) are one of the predominant microbes observed in immunocompromised patients with structural lung disease. Especially in immunocompromised patients, the treating physician needs to be aware of concurrent lung infections with opportunistic pathogens. In this case report we present a man in his 60s with severe chronic obstructive pulmonary disease (COPD) and bullous emphysema, who was diagnosed with Mycobacterium europaeum but with persistent clinical deterioration despite relevant treatment for NTM. A subsequent bronchoalveolar lavage (BAL) revealed elevated Aspergillus galactomannan antigen which, when seen in relation to imaging-findings of cavitating opacities with aggravating surrounding consolidation, raised suspicion of concurrent subacute invasive aspergillosis. Antifungal treatment was initiated but due to intolerable side effects was discontinued after only a few weeks. This case highlights the importance of concurrent testing for pulmonary aspergillosis in NTM patients and vice versa before treatment initiation and if the disease and symptoms are progressing despite relevant treatment.

Clinical characteristics and the diagnostic role of molecular tests in musculoskeletal infections caused by nontuberculous Mycobacterium: a single-center experience

PURPOSE

We retrospectively investigated NTM musculoskeletal infections to understand the clinical characteristics as well as the diagnostic performance of molecular tests as a useful supplementary test.

METHODS

A retrospective cohort study was conducted from January 2016 to December 2019. Intraoperative specimens for culture and pathological analysis were obtained during surgery under sterile conditions. AdvanSure TB/NTM real-time PCR (LG Life Sciences, Seoul, Korea) and PCR-reverse blot hybridization assay (REBA, REBA Myco-ID; YD Diagnostics, Yongin, Republic of Korea) was performed directly from tissue specimens for the rapid and accurate identification of 20 mycobacterial species.

RESULTS

A series of 24 patients was identified during the study period. Agricultural/aquatic exposure were predisposing factors in 9 patients, trauma in 4 patients, but no predisposing host factor was identified for 11 patients. Twenty-two patients presented with tenosynovitis and two with arthritis with substantial delays between initial presentation of symptoms and microbiologic diagnosis, with a median of 147 days (range 5-396 days). Pathologic tissue examination of musculoskeletal NTM infections was positive for chronic granulomatous inflammation in 18 cases. Fifteen were positive in the culture study, and nine were positive only in the molecular study using tissue specimens. All 6 M. ulcerans/M. marinum isolates were identified only by PCR.

CONCLUSIONS

This study is an important reminder that NTM infections should be a part of the differential diagnosis in patients with chronic musculoskeletal infections refractory to regular treatment. Although molecular test cannot replace the conventional smear and culture methods, it can be used as a useful supplementary test especially in diagnosing M. marinum infection.

Mortality association of nontuberculous mycobacterial infection requiring treatment in Taiwan: a population-based study

Background:

Infection due to nontuberculous mycobacteria (NTM) is an emerging issue worldwide, and we aimed to address the epidemiology and mortality association of NTM infection requiring treatment in Taiwan.

Methods:

We used the 2003–2018 data of 2 million representative individuals in Taiwan’s National Health Insurance Research Database. We identified patients with newly diagnosed NTM infection and received treatment as NTM cases. Age- and sex-matched (1:40) as well as propensity score-matched (PSM) (1:2) non-NTM individuals were selected as non-NTM controls. We used a Cox proportional hazard model to determine hazard ratios (HRs) with 95% confidence intervals (CIs).

Results:

We identified 558 patients with NTM infection requiring treatment. The mean age was 62.5 ± 15.4 years, and 57.5% of them were male. The incidence increased from 0.54 per 100,000 person-year in 2003 to 3.35 per 100,000 person-year in 2018. The overall mortality was 35.2%, with a mean follow-up duration of 4.1 ± 3.6 years. We found that NTM infection was independently associated with a greater risk of mortality (HR: 1.71; 95% CI: 1.47–1.98) compared with age- and sex-matched controls, and the association remained consistent (HR: 1.44; 95% CI: 1.19–1.75) compared with propensity-matched controls. We also found that old age, male, high Charlson comorbidity index, and the use of steroids or anti-neoplastic agents/immunosuppressants were associated with mortality risk.

Conclusion:

In conclusion, we found a steady increase in patients with NTM infection requiring treatment in Taiwan and further demonstrated that NTM infection was associated with greater risk of mortality using two comparable non-NTM control subjects.

Nontuberculous mycobacterial lung disease caused by Mycobacterium avium complex - disease burden, unmet needs, and advances in treatment developments

INTRODUCTION

Nontuberculous mycobacterial (NTM) lung disease (LD) is the most common clinical manifestation of NTM infection and is a growing health concern. Up to 85% of NTM-LD cases are caused by Mycobacterium avium complex (MAC). Increased awareness of NTM-LD caused by MAC is needed as patients with this disease experience substantial burden and unmet treatment needs.

AREAS COVERED

This review provides clinicians and regulatory and healthcare decision makers an overview of the clinical, economic, and humanistic burden of NTM-LD and the unmet treatment needs faced by patients and clinicians. The review focuses on NTM-LD caused by MAC. A summary of the 2020 NTM guidelines specifically for MAC-LD and an overview of novel treatment options, including amikacin liposome inhalation suspension (ALIS) as the first approved therapy for refractory MAC-LD, and investigational drugs in testing phase are provided.

EXPERT OPINION

Key advancements in NTM-LD management include recent updates to clinical practice guidelines, approval of ALIS for the treatment of refractory MAC-LD, and ongoing clinical trials of investigational treatments. Yet opportunities still exist to improve patient outcomes, including development of better screening tools, such as reliable and responsive biomarkers to help identify high-risk patients, and addressing unmet treatment needs.

The epidemiology of nontuberculous mycobacterial pulmonary disease in the Netherlands

Background

Nontuberculous mycobacteria (NTM) are emerging opportunistic pathogens of humans. Because NTM pulmonary disease (PD) is not a notifiable disease in Europe, the epidemiology of NTM-PD is not well known. However, the prevalence of NTM-PD is thought to be increasing, particularly in countries where tuberculosis rates have decreased. Here we aim to determine the prevalence of NTM-PD in the Netherlands.

Methods

Annual prevalence estimates of NTM-PD in the Netherlands (2012-2019) were derived from four separate databases, including two drug dispensing databases, an ICD-10 code database and a hospitalisation database. Databases covered a fraction of the Dutch population and were extrapolated. In addition, annual NTM-PD prevalence was also estimated by means of a pulmonologist survey.

Results

The estimated annual prevalence of NTM-PD using databases is between 2.3 and 5.9 patients per 100 000 inhabitants. Prevalence estimates derived from the drug dispensing databases, the hospitalisation database and the claims database were 2.3, 5.9, 3.5 and 4.5 per 100 000 inhabitants, respectively. The annual prevalence estimated in the pulmonologist survey was between 6.2 and 9.9 per 100 000 inhabitants. The annual prevalence remained stable over the included period.

Conclusion

The estimated annual prevalence of NTM-PD using databases was between 2.3 and 5.9 patients per 100 000 inhabitants. Due to the possible presence of tuberculosis patients and low coverage in one dispensing database, we believe an annual prevalence of between 2.3 and 4.5 patients per 100 000 inhabitants is more probable, which still renders NTM-PD a serious health threat. This estimate is lower than the estimate from the pulmonologist survey, indicating physicians likely overestimate prevalence.

Diagnostic Accuracy of Health Care Administrative Diagnosis Codes to Identify Nontuberculous Mycobacteria Disease: A Systematic Review

Background

Health care administrative database research frequently uses standard medical codes to identify diagnoses or procedures. The aim of this review was to establish the diagnostic accuracy of codes used in administrative data research to identify nontuberculous mycobacterial (NTM) disease, including lung disease (NTMLD).

Methods

We searched Ovid Medline, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov from inception to April 2019. We included studies assessing the diagnostic accuracy of International Classification of Diseases, 9th edition, Clinical Modification (ICD-9-CM) diagnosis codes to identify NTM disease and NTMLD. Studies were independently assessed by 2 researchers, and the Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess bias and quality.

Results

We identified 5549 unique citations. Of the 96 full-text articles reviewed, 7 eligible studies of moderate quality (3730 participants) were included in our review. The diagnostic accuracy of ICD-9-CM diagnosis codes to identify NTM disease varied widely across studies, with positive predictive values ranging from 38.2% to 100% and sensitivity ranging from 21% to 93%. For NTMLD, 4 studies reported diagnostic accuracy, with positive predictive values ranging from 57% to 64.6% and sensitivity ranging from 21% to 26.9%.

Conclusions

Diagnostic accuracy measures of codes used in health care administrative data to identify patients with NTM varied across studies. Overall the positive predictive value of ICD-9-CM diagnosis codes alone is good, but the sensitivity is low; this method is likely to underestimate case numbers, reflecting the current limitations of coding systems to capture NTM diagnoses.

Nucleic acid amplification techniques for rapid diagnosis of nontuberculous mycobacteria: A protocol of systematic review and meta-analysis

BACKGROUND

Nontuberculous mycobacteria (NTM) infection is similar to Mycobacterium tuberculosis (MTB) infection. Early clinical identification and differentiation of NTM and MTB infections continues to be a major challenge. Nucleic acid amplification tests (NAATs) have the ability to efficiently and rapidly detect pathogens and are widely used in mycobacterial infections. The objective of this study is to estimate the diagnostic accuracy of NAATs for NTM.

METHODS

We will search candidate studies that assessing the accuracy of NAATs for diagnosis of NTM through PubMed, Embase and the Cochrane Library until May 2021. Studies with full text that meet the inclusion criteria will be included. Following a revised tool for Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2), two researchers will independently evaluate the study quality. The STATA software (version 15.0) will be used to carry out meta-analyses. When heterogeneity is observed, subgroup analyses and meta-regression analyses will be used to explore sources of heterogeneity. Sensitivity analyses will be used to check the robustness of analyses.

CONCLUSION

We hope that this study will provide meaningful evidence for the early and rapid diagnosis of NAATs for NTM, which will help to guide the treatment of NTM and improve the prognosis of patients.

An update on prevalence of slow-growing mycobacteria and rapid-growing mycobacteria retrieved from hospital water sources in Iran - a systematic review

Introduction

This study aimed to assess the prevalence of slow growing mycobacteria (SGM) and rapid-growing mycobacteria (RGM) retrieved from hospital water sources in Iran from 2016 to 2020.

Methods

The review was conducted to get eligible published studies from 1^st January 2016 to 25^th March 2020 based on PRISMA protocol. A combination of related words from the Medical Subject Heading Terms (MeSH), with (AND, OR) were used to search for published studies reporting the prevalence of nontuberculous mycobacteria (NTM) in Scopus, MEDLINE, Web of Sciences, Google Scholar, and Iranian databases. Then data from the studies were extracted and reported.

Results

Our study showed that different water sources of hospitals were contaminated with NTMs. The prevalence of RGM isolates in hospital water samples varied between 42.2%-67.5%, and the prevalence of SGM varied between 32.5%-57.7%, respectively. M. lentiflavum (84.7%), M. avium complex(2.8%-56.4%)and M. gordonae (2.8%-56.2%) were the most prevalent NTM species amongst SGM, whereas M. fortuitum (2.9%-44.2%), M. chelonae (8%-36.8%), M. mucogenicum (8%-25.6%) were the most leading NTM isolates among RGM.

Conclusions

A high prevalence of NTM was reported from hospital environments particularly hospital water sources which can colonize medical devices, solutions, and water used for patients and cause nosocomial infection. Therefore, the hospitals should check the microbiological quality of the water used.

Drug Resistance in Nontuberculous Mycobacteria: Mechanisms and Models

The genus Mycobacteria comprises a multitude of species known to cause serious disease in humans, including Mycobacterium tuberculosis and M. leprae, the responsible agents for tuberculosis and leprosy, respectively. In addition, there is a worldwide spike in the number of infections caused by a mixed group of species such as the M. avium, M. abscessus and M. ulcerans complexes, collectively called nontuberculous mycobacteria (NTMs). The situation is forecasted to worsen because, like tuberculosis, NTMs either naturally possess or are developing high resistance against conventional antibiotics. It is, therefore, important to implement and develop models that allow us to effectively examine the fundamental questions of NTM virulence, as well as to apply them for the discovery of new and improved therapies. This literature review will focus on the known molecular mechanisms behind drug resistance in NTM and the current models that may be used to test new effective antimicrobial therapies.

Profiles of Extrapulmonary Nontuberculous Mycobacteria Infections and Predictors for Species: A Multicenter Retrospective Study

Extrapulmonary nontuberculous mycobacteria (NTM) infections contribute to morbidity and mortality worldwide. However, studies about extrapulmonary NTM infections have been limited. Therefore, we aim to describe the diversity of extrapulmonary NTM infections and identify predictors for species. Information regarding diversity of NTM isolates, antimicrobial susceptibility testing, treatment regimens, and outcomes were collected from four tertiary care centers in South Korea. Comparisons were made between patients with rapidly growing mycobacteria (RGM) and slowly growing mycobacteria (SGM) infections. A total of 117 patients (46 males vs. 71 females) were included. Skin and soft tissue infections (SSTIs) predominated (34.2%), followed by bone and joint infections (28.2%). In SSTIs, RGM species were predominantly identified (26/28, 92.9%), whereas SGM species were mainly identified in bone and joint infections (18/26, 69.2%), and the difference of isolated sites was verified by a post hoc test (p < 0.001). Multivariable regression analysis revealed that male sex (vs. female sex; OR 5.30, CI 1.35–24.26, p = 0.020) and bone and joint infections (vs. SSTIs; OR 18.10, CI 3.28–157.07, p = 0.002) were predictors of SGM infections, whereas the opposite was observed for RGM infections. Bone and joint infections and male sex were predictors for SGM infections, whereas SSTIs and female sex were predictors for RGM infections.

Mycobacterial Testing Trends, United States, 2009-20151

We studied 31 US healthcare facilities to characterize trends in mycobacterial testing. During 2009-2015, testing for acid-fast bacilli increased 3.2% annually, and prevalence of pathogenic nontuberculous mycobacteria increased 4.5% annually. These increases were highest for subpopulations at high risk of infection, including older women, Asians, and patients with concurrent conditions.

Strong increase of true and false positive mycobacterial cultures sent to the National Reference Centre in Belgium, 2007 to 2016

Introduction

In 2007, a new federal legislation in Belgium prohibited non-biosafety level 3 laboratories to process culture tubes suspected of containing mycobacteria.

Aim

To present mycobacterial surveillance/diagnosis data from the Belgian National Reference Centre for mycobacteria (NRC) from 2007 to 2016.

Methods

This retrospective observational study investigated the numbers of analyses at the NRC and false positive cultures (interpreted as containing mycobacteria at referring clinical laboratories, but with no mycobacterial DNA detected by PCR in the NRC). We reviewed mycobacterial species identified and assessed trends over time of proportions of nontuberculous mycobacteria (NTM) vs Mycobacterium tuberculosis complex (MTBc), and false positive cultures vs NTM.

Results

From 2007 to 2016, analyses requests to the NRC doubled from 12.6 to 25.3 per 100,000 inhabitants. A small but significant increase occurred in NTM vs MTBc proportions, from 57.9% (587/1,014) to 60.3% (867/1,437) (p < 0.001). Although NTM infection notification is not mandatory in Belgium, we annually received up to 8.6 NTM per 100,000 inhabitants. M. avium predominated (ca 20% of NTM cultures), but M. intracellulare culture numbers rose significantly, from 13.0% (74/587) of NTM cultures in 2007 to 21.0% (178/867) in 2016 (RR: 1.05; 95% CI: 1.03–1.07). The number of false positive cultures also increased, reaching 43.3% (1,097/2,534) of all samples in 2016.

Conclusion

We recommend inclusion of NTM in sentinel programmes. The large increase of false positive cultures is hypothesised to result from processing issues prior to arrival at the NRC, highlighting the importance of sample decontamination/transport and equipment calibration in peripheral laboratories.

The Use of Amikacin Liposome Inhalation Suspension (Arikayce) in the Treatment of Refractory Nontuberculous Mycobacterial Lung Disease in Adults

Nontuberculous mycobacteria (NTM) can cause and perpetuate chronic inflammation and lung infection. Despite having the diagnostic criteria, as defined by the American Thoracic Society (ATS) and Infectious Diseases Society of America (IDSA), clinicians find it challenging to diagnose and treat NTM-induced lung disease. Inhaled antibiotics are suitable for patients with lung infection caused by Pseudomonas aeruginosa and other organisms, but until recently, their utility in NTM-induced infection was not established. The most common NTM pathogens identified are the slow-growing Mycobacterium avium complex (MAC) and the rapid-growing M. abscessus complex (MABSC), both of which include several subspecies. Other less commonly isolated species include M. kansasii, M. simiae, and M. fortuitum. NTM strains are frequently more resistant than what is found in bacterial sputum cultures. Until recently, there was no approved inhaled antibiotic therapy for patients who were culture positive for pulmonary NTM infection. Of late, inhaled amikacin has been under investigation for the treatment of NTM-induced pulmonary infection. The FDA approved Arikayce (amikacin liposome inhalation suspension or ALIS) based on results from the ongoing Phase 3 CONVERT trial. In this study, the use of Arikayce met its primary endpoint of sputum culture conversion by the sixth month of treatment. The addition of Arikayce to guideline-based therapy led to negative sputum cultures for NTM by month 6 in 29% of patients compared to 8.9% of patients treated with guideline-based therapy alone. The effectiveness of Arikayce holds promise. However, due to limited data on Arikayce's safety, it is currently useful only for a specific population, particularly patients with refractory NTM-induced lung disease. Future trials must verify the target group and endorse the clinical benefits of Arikayce.

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

Background/objectives

Assessing 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.

Methods

We 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).

Results

Of 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).

Conclusion

In 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.

Mycobacterium arosiense, an unexpected cause of osteomyelitis in a patient with sarcoidosis: a case report

BACKGROUND

Nontuberculous mycobacteria belonging to the Mycobacterium avium complex are recognized as opportunistic pathogens to humans. Mycobacterium arosiense is one of the novel members of the Mycobacterium avium complex. The organism has only rarely been reported in human clinical cases and may be routinely misidentified.

CASE PRESENTATION

An adult male with a history of a discus prolapse and sarcoidosis presented with high fever and a strong back pain with projection to the extremities. A Magnetic Resonance Imaging scan of columna revealed a tumor suspect process at thoracic vertebrae 11/12 with changes at the second lumbar vertebra, which was partly removed by laminectomy. Biopsy smears revealed acid-fast bacilli and turned out to be Mycobacterium tuberculosis complex PCR negative. The routine line probe assay INNO-LiPa v2 (INNOGENETICS NV, Gent), which differentiates 16 mycobacterial species indicated the presence of a not readily identifiable NTM species. Whereas, the GenoType Mycobacterium CM v2.0 (HAIN Lifescience GmbH) that routinely differentiates 14 clinically relevant mycobacteria revealed a Mycobacterium intracellulare species. However, additional diagnostic sequencing of the 16S rRNA gene confirmed the presence of a Mycobacterium arosiense species.

CONCLUSIONS

This is the second unusual case of osteomyelitis with clinical significance ever to be reported, caused by Mycobacterium arosiense and complicated by an underlying sarcoidosis. Mycobacterium arosiense has rarely been reported clinically and the first description of the species was identified as the cause of osteomyelitis in a child with a hereditary partial interferon gamma deficiency. Symptoms attributed to sarcoidosis waned on Mycobacterium arosiense treatment and it is inconclusive whether the patient ever suffered from sarcoidosis. Mycobacterium arosiense was misidentified by the GenoType as Mycobacterium intracellulare and implicates that the diagnosis requires supplemental sequencing of the 16S rRNA gene.

Changing epidemiology of nontuberculous mycobacterial lung disease over the last two decades in a region of the Basque country

Recent studies suggest an increasing prevalence of nontuberculous mycobacteria (NTM) lung disease. The aim of the present study was to describe incidence rates of NTM lung disease and trends therein in our area over a 20-year period. This was a retrospective study of all cases of NTM lung disease between 1997 and 2016 that met the 2007 American Thoracic Society criteria. We analysed the annual incidence rates, species of mycobacteria isolated, trends over time and annual mortality in 327 patients. Mycobacterium kansasii was the most common mycobacterium isolated (84%), followed by Mycobacterium avium complex (MAC) (13%). We compared two periods: 1997-2006 (257 cases, 79%) and 2007-2016 (70 cases, 21%). The incidence rates tended to decrease across these years, with a peak of incidence in 2000 with 10.6 cases per 100 000. There was a clearly decreasing trend in M. kansasii infection, not only in the first period (incident rate ratio (IRR) 0.915, 95% CI 0.88-0.90; p<0.0001) but also in the second (IRR 0.869, 95% CI 0.780-1.014; p=0.080), reaching 1.8 per 100 000 in 2016. In contrast, MAC infection tended to increase across the two periods (IRR 1.251, 95% CI 1.081-1.447; p=0.003). In our region, the incidence of NTM lung disease has notably decreased in recent years. M. kansasii had high incidence rates in the first decade but clearly decreased in the second decade.

Increase in Childhood Nontuberculous Mycobacterial Infections After Bacille Calmette-Guérin Coverage Drop: A Nationwide, Population-Based Retrospective Study, Finland, 1995-2016

Background

Epidemiological data on childhood nontuberculous mycobacterial (NTM) disease is scarce and the protective effect of bacille Calmette-Guérin (BCG) vaccination remains debated. In 2006, the BCG policy in Finland changed from universal to selective. We aimed to study the effect of the BCG coverage decrease on the incidence of childhood NTM infections in Finland.

Methods

We conducted a nationwide, population-based, retrospective study of NTM notifications recorded to the National Infectious Diseases Register between 1995 and 2016 and identified native-born children aged 0-4 years infected with NTM. Poisson log-linear model was used to estimate the change in the incidence rate of cohorts born during universal or selective BCG policy between 1995 and 2015.

Results

We identified 97 native-born children aged <5 years infected with NTM (median age, 27 months; female-to-male ratio, 2:1). The most common species was Mycobacterium avium (n = 69 [71%]). The estimated incidence rates of NTM in universal-BCG and selective-BCG cohorts were 0.2 and 3.9 per 100000 person-years, respectively. The incidence rate ratio of selective-BCG cohorts compared to universal-BCG cohorts was 19.03 (95% confidence interval, 8.82-41.07; P < .001).

Conclusions

After infant BCG coverage in Finland decreased, childhood NTM infections increased drastically. As there is no other apparent cause for the increase, this indicates that BCG offers protection against childhood NTM disease. This observation adds to the understanding of childhood NTM epidemiology and might explain why the disease is emerging in some countries.

Socio-Economic and Environmental Factors Related to Spatial Differences in Human Non-Tuberculous Mycobacterial Diseases in the Czech Republic

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental bacteria that can induce pulmonary and non-pulmonary diseases in susceptible persons. It is reported that the prevalence of NTM diseases is increasing in developed countries, but this differs by regions and countries. NTM species distribution and the rate of diseases caused by NTM vary widely in the historical territories of Moravia and Silesia (Czech Republic). This epidemiologic study of NTM diseases covers the period 2012–2018, reviews isolates obtained from patients with clinical disease and investigates correlations with related socio-economic and environmental factors. Individual NTM patients were included only once during the studied period and results were presented as incidence rate per year. The most frequently isolated NTM meeting the microbiological and clinical criteria in the study were the Mycobacterium avium-intracellulare complex, followed by Mycobacterium kansasii and Mycobacteriumxenopi. A previously described endemic incidence of M.kansasii in the Karviná district and M.xenopi in the Ostrava district was also observed in this study. The incidence of NTM patients in the whole studied territory was 1.10/100,000 inhabitants (1.33/100,000 in men and 0.88/100,000 in women). The annual incidence of lymphadenitis in children (≤5 years of age) was 2.35/100,000 of the population of children during the 7 year period but increased in the year 2018 to 5.95/100,000. The rate of human tuberculosis in the studied area was 1.97/100,000 inhabitants. The incidence of NTM pulmonary diseases correlated with a lower socio-economic status (r = 0.63) and a higher concentration of benzo[a]pyrene pollution in the air (r = 0.64).

Hypercalcaemia secondary to disseminated Mycobacterium abscessus and Mycobacterium fortuitum

The incidence and prevalence of nontuberculous mycobacteria (NTM) infection is on the rise with many cases still going unreported. Given the vague and nonspecific clinical features of NTM infections, it is often missed or mistaken for Mycobacterium tuberculosis. The presumption that NTM infections are benign and do not contribute to morbidity no longer holds true. NTM infections need to be considered in patients with disseminated multisystem disease and in those not responding to standard M. tuberculosis treatment. As NTM infection is associated with granuloma formation, it can result in hypercalcaemia. Interestingly, there is evidence that there may be other mechanisms in play contributing to hypercalcaemia besides the increased calcitriol levels.

Diagnosis and treatment of patients with pulmonary nontuberculous mycobacterial diseases in Arkhangelsk, Russia

BACKGROUND

Nontuberculous mycobacteria (NTM) are acid-fast bacilli (AFB) that can cause disease in human. Patients with NTM pulmonary disease can be falsely diagnosed with pulmonary tuberculosis (TB) due detection of AFB in sputum and similar clinical and chest X-ray picture. Laboratory detection of NTM is complicated and does not always mean presence of the disease, but can be attributed to colonization or sample contamination. Molecular tests, such as Genotype Mycobacterium CM/AS, allow quick and reliable detection of NTM.

OBJECTIVE

To assess the NTM identification rate, to estimate the incidence of pulmonary NTM disease and to report the treatment outcomes among patients with NTM disease.

DESIGN

Retrospective cohort design.

RESULTS

NTM were detected among 92 (0.98 per 100,000 population) presumptive pulmonary TB patients in Arkhangelsk region in 2010-2017 among who 39 (0.42 per 100,000 population) patients were diagnosed with NTM disease. The most prevalent species found in our study were M. avium (33%) and M.intracellulare (11%). 69% of patients with NTM disease completed their treatment, 15% died, 13% were lost to follow up and 3% failed treatment.

CONCLUSION

A system of diagnostics and treatment for NTM disease was set up in the Arkhangelsk region in Russia. Average NTM identification rate and incidence of pulmonary NTM disease were 0.98 per 100,000 and 0.42 per 100,000 population accordingly and were lower than reported in other studies. Treatment success rate in our study was 69% encouraging further improvements in diagnostics and treatment of patients with NTM.

Ribosomal maturation factor (RimP) is essential for survival of nontuberculous mycobacteria Mycobacterium fortuitum under in vitro acidic stress conditions

Mycobacterium fortuitum is an important human pathogenic NTM, which resists stress conditions inside macrophages by exploitation of specific genes. TnphoA-based transposon mutagenesis was employed to identify membrane genes responsible for survival of M. fortuitum under such stress conditions. A library of about 450 mutants was constructed after electroporation of vector pRT291 into wild-type M. fortuitum. On the basis of blue color development and alkaline phosphatase assay, 20 mutants were shortlisted to screen for growth and survival under acidic stress at pH 6.5, 5.5, 4.5, and 3.5. Mutant MT727 showed reduced growth and survival under acidic stress. The acid susceptible mutant MT727 was subjected to other in vitro stress conditions prevalent inside macrophages including oxidative, nutrient starvation and nitrosative stress. However, the mutant showed no appreciable difference in growth behavior under oxidative, nutrient starvation and nitrosative stress conditions in comparison to the wild type. Genomic and bioinformatics analysis of MT727 led to identification of putative ribosomal maturation factor RimP of M. fortuitum to be affected by mutagenesis, showing closest homology to M. abscessus RimP. In silico functional interaction of RimP protein using STRING database showed its interaction with proteins of ribosomal assembly and maturation. Results indicate role of rimP gene in survival of M. fortuitum under acidic stress conditions which may be further explored for use as a potential drug target against M. fortuitum and other mycobacterial infections.

The complexities and challenges of preventing and treating nontuberculous mycobacterial diseases

Seemingly innocuous nontuberculous mycobacteria (NTM) species, classified by their slow or rapid growth rates, can cause a wide range of illnesses, from skin ulceration to severe pulmonary and disseminated disease. Despite their worldwide prevalence and significant disease burden, NTM do not garner the same financial or research focus as Mycobacterium tuberculosis. In this review, we outline the most abundant of over 170 NTM species and inadequacies of diagnostics and treatments and weigh the advantages and disadvantages of currently available in vivo animal models of NTM. In order to effectively combat this group of mycobacteria, more research focused on appropriate animal models of infection, screening of chemotherapeutic compounds, and development of anti-NTM vaccines and diagnostics is urgently needed.

Mycobacterium avium: an overview

Mycobacterium avium is an environmental microorganism found in soil and water sources worldwide. It is the most prevalent species of nontuberculous mycobacteria that causes infectious diseases, especially in immunocompromised individuals. This review discusses and highlights key topics about M. avium, such as epidemiology, pathogenicity, glycopeptidolipids, laboratory identification, genotyping, antimicrobial therapy and antimicrobial resistance. Additionally, the main comorbidities associated with M. avium infection are discussed.

Treatment of Extrapulmonary Nontuberculous Mycobacterial Diseases

Nontuberculous mycobacteria (NTM) diseases mainly manifest as pulmonary illnesses, but 20 -30% of NTM isolates originate from extrapulmonary diseases. These diseases cause a variety of clinical syndromes, including skin and soft-tissue infections, musculoskeletal infections, lymphadenitis, and disseminated disease. In skin and soft-tissue infections, musculoskeletal infections, prolonged treatment with combinations of antibiotics is effective in the treatment of NTM diseases, with surgery as an important complementary tool. The recommended duration of therapy for skin and soft-tissue infection is usually 2 – 4 months for mild disease and 6 months for severe disease, while treatment of musculoskeletal NTM disease usually requires at least 6 - 12 months. Management options of NTM lymphadenitis include surgical intervention, medical therapy, or observation. Treatment of disseminated NTM disease generally requires 6 to 12 months after immune restoration. However, despite a considerable increase in knowledge about NTM diseases, determining optimal treatment approaches remains a complex and challenging task.

Nontuberculous mycobacterial disease managed within UK primary care, 2006-2016

Previous UK studies investigating nontuberculous mycobacteria have been limited to reporting isolation from culture, not burden of disease. We assessed the burden of nontuberculous mycobacterial disease (NTMD) in UK primary care from 2006 to 2016. Using electronic healthcare records, we identified patients with NTMD using a strict definition including patients with guideline-directed treatment/monitoring. We described treatment regimens and incidence/prevalence in the general population and in patients with underlying chronic respiratory diseases. Incidence of primary care-managed NTMD in the general population decreased (2006 to 2016 rates per 100,000 person-years, 3.85 to 1.28). Average annual prevalence of NTMD in the general population was 6.38 per 100,000. Around 85% were taking antimycobacterial therapy; 53.2% were taking a guideline-recommended regimen. Incidence of NTMD in patients with respiratory disease decreased (2006 to 2016 rates per 100,000 person-years, 12.5 to 7.40). Average annual prevalence of NTMD in patients with respiratory disease was 27.7 per 100,000. This is the first UK study using nationally representative data to investigate the burden of NTMD managed within primary care. Incidence and prevalence of managed NTMD within primary care is gradually declining. Increasing complexity in the management of NTMD may be driving a shift in care to secondary settings.

Mycobacterium marinum infections in Denmark from 2004 to 2017: A retrospective study of incidence, patient characteristics, treatment regimens and outcome

Mycobacterium marinum (M. marinum) is a slowly growing nontuberculous mycobacterium. The incidence of M. marinum infections in Denmark is unknown. We conducted a retrospective nationwide study including all culture confirmed cases of M. marinum from 2004 to 2017 in Denmark. All available medical records were reviewed. Demographics, clinical characteristics, and treatment regiments were analyzed. Fifty-five patients were identified, 40 (72.7%) were men with a median age of 50 years. Aquatic exposure was reported by 48 (90.6%) of the patients. Site of infection was upper extremities in 49 (92.5%) patients and 49 (92.5%) had superficial infection. The median time from symptom presentation to diagnosis was 194 days. All patients received antibiotics. Median time of treatment duration among all patients was 112 days. Treatment outcome was classified as improved in 40 (75%), improved with sequela in 4 (7.6%) patients and only 3 patients (3.8%) were classified as failed. Infection with M. marinum is rare and there is a long delay from symptom manifestation to diagnosis. The infection is predominantly related to aquatic exposure. M. marinum should be a differential diagnose in patients with slow-developing cutaneous elements and relevant exposure. Treatment outcomes are overall good and severe sequela are rare.

Clinical characteristics of non-tuberculous mycobacterial pulmonary infections in Bamako, Mali

The global spread of non-tuberculous mycobacteria (NTM) may be due to HIV/AIDS and other environmental factors. The symptoms of NTM and tuberculosis (TB) disease are indistinguishable, but their treatments are different. Lack of research on the epidemiology of NTM infections has led to underestimation of its prevalence within TB endemic countries. This study was designed to determine the prevalence and clinical characteristics of pulmonary NTM in Bamako. A cross-sectional study which include 439 suspected cases of pulmonary TB. From 2006 to 2013 a total of 332 (76%) were confirmed to have sputum culture positive for mycobacteria. The prevalence of NTM infection was 9.3% of our study population and 12.3% of culture positive patients. The seroprevalence of HIV in NTM group was 17.1%. Patients who weighed <55 kg and had TB symptoms other than cough were also significantly more likely to have disease due to NTM as compared to those with TB disease who were significantly more likely to have cough and weigh more than 55 kg (OR 0.05 (CI 0.02–0.13) and OR 0.32 (CI 0.11–0.93) respectively). NTM disease burden in Bamako was substantial and diagnostic algorithms for pulmonary disease in TB endemic countries should consider the impact of NTM.