Spatial clusters of nontuberculous mycobacterial lung disease in the United States

Draft Genome Sequence of Mycobacterium virginiense Strain GF75, Isolated from the Mud of a Swine Farm in Japan

Mycobacterium virginiense, a newly described species of the Mycobacterium terrae complex, is a cause of tenosynovitis and osteomyelitis in the United States. Here, we report the 4,849,424-bp draft genome sequence of M. virginiense strain GF75, isolated from a mud sample taken from a Japanese swine farm.

Mycobacterium abscessus Complex Infections: A Retrospective Cohort Study

Background

Infections caused by Mycobacterium abscessus group strains are usually resistant to multiple antimicrobials and challenging to treat worldwide. We describe the risk factors, treatment, and clinical outcomes of patients in 2 large academic medical centers in the United States.

Methods

A retrospective cohort study of hospitalized adults with a positive culture for M. abscessus in Miami, Florida (January 1, 2011, to December 31, 2014). Demographics, comorbidities, the source of infection, antimicrobial susceptibilities, and clinical outcomes were analyzed. Early treatment failure was defined as death and/or infection relapse characterized either by persistent positive culture for M. abscessus within 12 weeks of treatment initiation and/or lack of radiographic improvement.

Results

One hundred eight patients were analyzed. The mean age was 50.81 ± 21.03 years, 57 (52.8%) were females, and 41 (38%) Hispanics. Eleven (10.2%) had end-stage renal disease, 34 (31.5%) were on immunosuppressive therapy, and 40% had chronic lung disease. Fifty-nine organisms (54.6%) were isolated in respiratory sources, 21 (19.4%) in blood, 10 (9.2%) skin and soft tissue, and 9 (8.3%) intra-abdominal. Antimicrobial susceptibility reports were available for 64 (59.3%) of the patients. Most of the isolates were susceptible to clarithromycin, amikacin, and tigecycline (93.8%, 93.8%, and 89.1%, respectively). None of the isolates were susceptible to trimethoprim/sulfamethoxazole, and only 1 (1.6%) was susceptible to ciprofloxacin. Thirty-six (33.3%) patients early failed treatment; of those, 17 (15.7%) died while hospitalized. On multivariate analysis, risk factors significantly associated with early treatment failure were disseminated infection (odds ratio [OR], 11.79; 95% confidence interval [CI], 1.53–81.69; P = .04), acute kidney injury (OR, 6.55; 95% CI, 2.4–31.25; P = .018), organ transplantation (OR, 2.37; 95% CI, 2.7–23.1; P = .005), immunosuppressive therapy (OR, 2.81; 95% CI, 1.6–21.4; P = .002), intravenous amikacin treatment (OR, 4.1; 95% CI, 0.9–21; P = .04), clarithromycin resistance (OR,79.5; 95% CI, 6.2–3717.1, P < .001), and presence of prosthetic device (OR, 5.43; 95% CI, 1.57–18.81; P = .008). Receiving macrolide treatment was found to be protective against early treatment failure (OR, 0.13; 95% CI, 0.002–1.8; P = .04).

Conclusions

Our cohort of 108 M. abscessus complex isolates in Miami, Florida, showed an in-hospital mortality of 15.7%. Most infections were respiratory. Clarithromycin and amikacin were the most likely agents to be susceptible in vitro. Resistance to fluoroquinolone and trimethoprim/sulfamethoxazole was highly common. Macrolide resistance, immunosuppression, and renal disease were significantly associated with early treatment failure.

Epidemiology of Nontuberculous Mycobacterial Lung Disease and Tuberculosis, Hawaii, USA

Previous studies found Hawaiians and Asian-Americans/Pacific Islanders to be independently at increased risk for nontuberculous mycobacterial pulmonary disease (NTMPD) and tuberculosis (TB). To better understand NTM infection and TB risk patterns in Hawaii, USA, we evaluated data on a cohort of patients in Hawaii for 2005–2013. Period prevalence of NTMPD was highest among Japanese, Chinese, and Vietnamese patients (>300/100,000 persons) and lowest among Native Hawaiians and Other Pacific Islanders (50/100,000). Japanese patients were twice as likely as all other racial/ethnic groups to have Mycobacterium abscessus isolated (adjusted odds ratio 2.0, 95% CI 1.2–3.2) but were not at increased risk for infection with other mycobacteria species. In contrast, incidence of TB was stable and was lowest among Japanese patients (no cases) and highest among Filipino, Korean, and Vietnamese patients (>50/100,000). Substantial differences exist in the epidemiology of NTMPD by race/ethnicity, suggesting behavioral and biologic factors that affect disease susceptibility.

Epidemiologic and Spatiotemporal Characterization of Influenza and Severe Acute Respiratory Infection in Uganda, 2010-2015

RATIONALE

Little is known about the epidemiology of severe acute respiratory infection (SARI) or influenza in sub-Saharan Africa. Characterization of influenza transmission dynamics and risk factors for severe disease and mortality is critical to inform prevention and mitigation strategies.

OBJECTIVES

To characterize the epidemiology and transmission dynamics of influenza and risk factors for influenza-associated severe respiratory infection in Uganda.

METHODS

Clinicians at 12 sentinel surveillance sites prospectively collected clinical data and upper respiratory tract samples from consecutive patients who met criteria for SARI and influenza-like illness (ILI). Samples were tested for influenza A and B viruses using real-time reverse transcription-polymerase chain reaction. Spatial and spatiotemporal cluster modeling was performed to identify loci of increased influenza transmission. Morbidity and mortality were assessed through chart review in a defined subset of patients. Univariable and multivariable analyses were used to identify risk factors for severe respiratory infection, prolonged hospitalization, and in-hospital mortality.

MEASUREMENTS AND MAIN RESULTS

From October 2010 to June 2015, 9,978 patients met case definitions for SARI and ILI and had samples tested for influenza A and B. Of the 9,978 patient samples tested, 1,113 (11.2%) were positive for influenza. Among 6,057 patients with ILI, 778 samples (12.8%) were positive, and among 3,921 patients with SARI, 335 samples (8.5%) were positive. Significant clustering of influenza cases was observed in urban and periurban areas and during rainy seasons. Among 1,405 cases of SARI with available outcome data, in-hospital mortality was 1.6%. Infection with the 2009 pandemic A/H1N1 subtype and prolonged time to presentation were independently associated with SARI among influenza cases.

CONCLUSIONS

Influenza is associated with a substantial proportion of acute respiratory infection in Uganda. As influenza vaccination programs are developed in East Africa, timing campaigns to confer protection during rainy seasons should be considered, particularly among high-risk urban populations.

On the Reportability of Nontuberculous Mycobacterial Disease to Public Health Authorities

Nontuberculous mycobacteria (NTM) are environmental pathogens that are an increasingly common cause of pulmonary and extrapulmonary disease. Electronic laboratory-based reporting is a straightforward mechanism for identifying NTM infections and for monitoring trends in disease. Oregon was the first state to make NTM reportable, although at this time the reporting requirement is limited to extrapulmonary infection. This has assisted authorities in detecting outbreaks and healthcare-related infections. However, further consideration should be given to the reportability of pulmonary NTM disease. Pulmonary NTM disease is more common than tuberculosis in the United States and is of emerging public health concern. Although the direct public health action that would be triggered by a pulmonary NTM disease report is not clear, without surveillance, public health is missing an opportunity to better understand pulmonary NTM disease trends and reasons for its increasing recognition within our population. We believe state health authorities should conduct surveillance for pulmonary NTM, either by mandating reporting of laboratory isolates or by other mechanisms as we have done in Oregon.

Notification of Nontuberculous Mycobacteria: An Australian Perspective

In Queensland, Australia, all cases of mycobacterial infection (tuberculosis [TB] and nontuberculous mycobacteria [NTM]) are notifiable under the Queensland Public Health Act (2005). This process originally emerged to avoid NTM confounding with notification of cases of TB, but has facilitated awareness of the increasing incidence and changing epidemiology of NTM. Although initially not a public health priority, the notification process has facilitated research that has led to an appreciation of both public health and environmental health issues associated with these pathogens. When reports of NTM infections were low in frequency, reporting was managed largely by clinicians specializing in TB. However, as reports of NTM isolates surpassed those for TB, the workload associated with clinical reporting exceeded resources. The Communicable Diseases Branch transitioned to digital reporting of laboratory isolates of mycobacteria, thereby enabling weekly and quarterly reporting of data, and generation of more detailed annual reports. The reports now include species and geographic distributions by health service district, allowing identification of clusters requiring further investigation and systematic reviews of different species. With ecological and climate change, the distribution and virulence of these emerging pathogens are evolving. Evidence of transmission of highly virulent and antibiotic-resistant clones of Mycobacterium abscessus among patients with cystic fibrosis internationally heightens the need for timely reporting to public health authorities. Ongoing systematic monitoring by public health authorities will be crucial to our understanding of NTM diseases.

Pulmonary disease by non-tuberculous mycobacteria - clinical management, unmet needs and future perspectives

INTRODUCTION

The number of patients with pulmonary disease caused by non-tuberculous mycobacteria (NTM) is increasing globally. Poor resistance against infections, for example, due to pre-existing lung diseases, immune deficiency and immune-modulating treatment, predisposes the population to developing pulmonary NTM disease. The incidence of pre-existing lung diseases such as chronic obstructive pulmonary disease and bronchiectasis has also increased. NTM disease diagnosis is often delayed due to non-specific symptoms. The therapeutic arsenal is limited and adherence to treatment guidelines is often low since the treatment regimens are complex, lengthy and side effects are common. Thus, current disease management is far from satisfactory and needs to be improved. Areas covered: This review provides an overview of the current knowledge of NTM infections and includes pathogenesis, disease patterns, epidemiology, disease management, unmet needs and future perspectives. Expert commentary: NTM disease is becoming more prevalent, in part with our increased awareness and improved diagnostic methods. However, our understanding of the disease pathogenesis is limited and treatment decisions are challenging, with difficult to employ drug regimens. Optimal management requires collaboration between healthcare providers, patients and expert centers.

Mycobacterium avium Complex Disease

Despite the ubiqitous nature of Mycobacterium avium complex (MAC) organisms in the environment, relatively few of those who are infected develop disease. Thus, some degree of susceptibility due to either underlying lung disease or immunosuppression is required. The frequency of pulmonary MAC disease is increasing in many areas, and the exact reasons are unknown. Isolation of MAC from a respiratory specimen does not necessarily mean that treatment is required, as the decision to treatment requires the synthesis of clinical, radiographic, and microbiologic information as well as a weighing of the risks and benefits for the individual patient. Successful treatment requires a multipronged approach that includes antibiotics, aggressive pulmonary hygiene, and sometimes resection of the diseased lung. A combination of azithromycin, rifampin, and ethambutol administered three times weekly is recommend for nodular bronchiectatic disease, whereas the same regimen may be used for cavitary disease but administered daily and often with inclusion of a parenteral aminoglycoside. Disseminated MAC (DMAC) is almost exclusively seen in patients with late-stage AIDS and can be treated with a macrolide in combination with ethambutol, with or without rifabutin: the most important intervention in this setting is to gain HIV control with the use of potent antiretroviral therapy. Treatment outcomes for many patients with MAC disease remain suboptimal, so new drugs and treatment regimens are greatly needed. Given the high rate of reinfection after cure, one of the greatest needs is a better understanding of where infection occurs and how this can be prevented.

Household proximity to water and nontuberculous mycobacteria in children with cystic fibrosis

BACKGROUND

Nontuberculous mycobacteria (NTM) have a particular affinity for patients with cystic fibrosis (CF). Recent studies suggest a possible relationship between acquiring NTM and the level of environmental water in a given area. We sought to determine if there is an association between household proximity to water and NTM in children with CF.

MATERIALS AND METHODS

An IRB-approved retrospective chart review was completed on 150 children with CF in Florida. Inclusion criteria required regular follow-up, at least two acid-fast bacilli cultures, and a consistent home address over a 3-year period. The distance from each patient's home to the nearest body of water was measured using ArcMap®, a Geographic Information System, and the mean distance to water for NTM-positive and NTM-negative groups were compared. A stepwise backwards logistic regression was used to evaluate for predictors of NTM-positivity.

RESULTS

Of the 150 CF patients, 65 met inclusion criteria and 21 (32.3%) tested positive for NTM. Comparison of the mean distance to water for NTM-positive versus NTM-negative groups revealed a cutoff of 500 meters. On the logistic regression, CF patients who lived within 500 meters of water were 9.4 times more likely to acquire NTM (P = 0.013). Other significant predictors included a history of Aspergillus fumigatus (OR 7.9, P = 0.011) and recent history of Pseudomonas aeruginosa (OR 2.5, P = 0.007).

CONCLUSIONS

In the regions studied, children with CF who live closer to water are more likely to acquire nontuberculous mycobacteria. Future studies in other geographic areas are needed to determine if these results are generalizable. Pediatr Pulmonol. 2017;52:324-330. © 2016 Wiley Periodicals, Inc.

Dose response models and a quantitative microbial risk assessment framework for the Mycobacterium avium complex that account for recent developments in molecular biology, taxonomy, and epidemiology

Mycobacterium avium complex (MAC) is a group of environmentally-transmitted pathogens of great public health importance. This group is known to be harbored, amplified, and selected for more human-virulent characteristics by amoeba species in aquatic biofilms. However, a quantitative microbial risk assessment (QMRA) has not been performed due to the lack of dose response models resulting from significant heterogeneity within even a single species or subspecies of MAC, as well as the range of human susceptibilities to mycobacterial disease. The primary human-relevant species and subspecies responsible for the majority of the human disease burden and present in drinking water, biofilms, and soil are M. avium subsp. hominissuis, M. intracellulare, and M. chimaera. A critical review of the published literature identified important health endpoints, exposure routes, and susceptible populations for MAC risk assessment. In addition, data sets for quantitative dose-response functions were extracted from published in vivo animal dosing experiments. As a result, seven new exponential dose response models for human-relevant species of MAC with endpoints of lung lesions, death, disseminated infection, liver infection, and lymph node lesions are proposed. Although current physical and biochemical tests used in clinical settings do not differentiate between M. avium and M. intracellulare, differentiating between environmental species and subspecies of the MAC can aid in the assessment of health risks and control of MAC sources. A framework is proposed for incorporating the proposed dose response models into susceptible population- and exposure route-specific QMRA models.

[Nontuberculous mycobacterial pulmonary disease]

Nontuberculous mycobacteria (NTM) are a group of biologically diverse, ubiquitous and naturally multi-drug resistant bacteria with facultative pathogenicity. Recent data suggest that their clinical significance is increasing worldwide and that susceptible individuals may be at risk for infection via contaminated surfaces and aerosols. These individuals often have a predisposition for chronic respiratory diseases, e. g. bronchiectasis, chronic obstructive pulmonary disease (COPD) and cystic fibrosis and these conditions frequently share the same unspecific signs and symptoms with NTM pulmonary disease (NTM-PD). As a consequence, the diagnosis of NTM-PD, which is established based on clinical, radiological and microbiological criteria, is often delayed. Treating NTM-PD is more demanding than treating pulmonary tuberculosis as therapy is generally more tedious, toxic and expensive as well as being prone to failure. Patient and pathogen-specific factors guide the choice of an appropriate antimicrobial combination regimen, which should comply with national and international recommendations. Adverse events are common, should be anticipated and closely monitored. If infections with infrequently encountered mycobacterial species and severe or refractory disease occur, an interdisciplinary approach should be used, involving infectious disease specialists, experienced thoracic surgeons and referral to an NTM specialist center.

Environmental Nontuberculous Mycobacteria in the Hawaiian Islands

Lung disease caused by nontuberculous mycobacteria (NTM) is an emerging infectious disease of global significance. Epidemiologic studies have shown the Hawaiian Islands have the highest prevalence of NTM lung infections in the United States. However, potential environmental reservoirs and species diversity have not been characterized. In this cross-sectional study, we describe molecular and phylogenetic comparisons of NTM isolated from 172 household plumbing biofilms and soil samples from 62 non-patient households and 15 respiratory specimens. Although non-uniform geographic sampling and availability of patient information were limitations, Mycobacterium chimaera was found to be the dominant species in both environmental and respiratory specimens. In contrast to previous studies from the continental U.S., no Mycobacterium avium was identified. Mycobacterium intracellulare was found only in respiratory specimens and a soil sample. We conclude that Hawai’i’s household water sources contain a unique composition of Mycobacterium avium complex (MAC), increasing our appreciation of NTM organisms of pulmonary importance in tropical environments.

In the U.S., the Hawaiian Islands have the highest number of nontuberculous mycobacterial (NTM) lung disease cases per capita. The tropical climate, geographical isolation of the islands, and aquifer water sources may have influence such prevalence. Previous studies suggest that NTM thrive in water biofilms and soil. To broaden our understanding of potential environmental reservoirs and species composition of NTM in the Hawaiian Islands, we sampled environmental sites and examined patient isolates. Our recovery and identification of Mycobacterium chimaera and several other clinically relevant NTM species and the absence of Mycobacterium avium in both the indigenous environment and clinical specimens underscore the need for further studies to define the environmental factors that drive NTM lung disease and species composition in high prevalence locations such as the Hawaiian Islands.

The Burden of Pulmonary Nontuberculous Mycobacterial Disease in the United States

RATIONALE

State-specific case numbers and costs are critical for quantifying the burden of pulmonary nontuberculous mycobacterial disease in the United States.

OBJECTIVES

To estimate and project national and state annual cases of nontuberculous mycobacterial disease and associated direct medical costs.

METHODS

Available direct cost estimates of nontuberculous mycobacterial disease medical encounters were applied to nontuberculous mycobacterial disease prevalence estimates derived from Medicare beneficiary data (2003-2007). Prevalence was adjusted for International Classification of Diseases, 9th Revision, undercoding and the inclusion of persons younger than 65 years of age. U.S. Census Bureau data identified 2010 and 2014 population counts and 2012 primary insurance-type distribution. Medical costs were reported in constant 2014 dollars. Projected 2014 estimates were adjusted for population growth and assumed a previously published 8% annual growth rate of nontuberculous mycobacterial disease prevalence.

MEASUREMENTS AND MAIN RESULTS

In 2010, we estimated 86,244 national cases, totaling to $815 million, of which 87% were inpatient related ($709 million) and 13% were outpatient related ($106 million). Annual state estimates varied from 48 to 12,544 cases ($503,000-$111 million), with a median of 1,208 cases ($11.5 million). Oceanic coastline states and Gulf States comprised 70% of nontuberculous mycobacterial disease cases but 60% of the U.S. population. Medical encounters among individuals aged 65 years and older ($562 million) were twofold higher than those younger than 65 years of age ($253 million). Of all costs incurred, medications comprised 76% of nontuberculous mycobacterial disease expenditures. Projected 2014 estimates resulted in 181,037 national annual cases ($1.7 billion).

CONCLUSIONS

For a relatively rare disease, the financial cost of nontuberculous mycobacterial disease is substantial, particularly among older adults. Better data on disease dynamics and more recent prevalence estimates will generate more robust estimates.

Diagnosis and Treatment of Nontuberculous Mycobacterial Lung Disease

Nontuberculous mycobacteria (NTM) are ubiquitous organisms; their isolation from clinical specimens does not always indicate clinical disease. The incidence of NTM lung diseases has been increasing worldwide. Although the geographic diversity of NTM species is well known, Mycobacterium avium complex (MAC), M. abscessus complex (MABC), and M. kansasii are the most commonly encountered and important etiologic organisms. Two distinct types of NTM lung diseases have been reported, namely fibrocavitary and nodular bronchiectatic forms. For laboratory diagnosis of NTM lung diseases, both liquid and solid media cultures and species-level identification are strongly recommended to enhance growth detection and determine the clinical relevance of isolates. Treatment for NTM lung diseases consists of a multidrug regimen and a long course of therapy, lasting more than 12 months after negative sputum conversion. For MAC lung disease, several new macrolide-based regimens are now recommended. For nodular bronchiectatic forms of MAC lung diseases, an intermittent three-time-weekly regimen produces outcomes similar to those of daily therapy. Treatment of MABC lung disease is very difficult, requiring long-term use of parenteral agents in combination with new macrolides. Treatment outcomes are much better for M. massiliense lung disease than for M. abscessus lung disease. Thus, precise identification of species in MABC infection is needed for the prediction of antibiotic response. Likewise, increased efforts to improve treatment outcomes and develop new agents for NTM lung disease are needed.

Pulmonary Disease Due to Nontuberculous Mycobacteria: Current State and New Insights

Since pulmonary nontuberculous mycobacteria (PNTM) lung disease was last reviewed in CHEST in 2008, new information has emerged spanning multiple domains, including epidemiology, transmission and pathogenesis, clinical presentation, diagnosis, and treatment. The overall prevalence of PNTM is increasing, and in the United States, areas of highest prevalence are clustered in distinct geographic locations with common environmental and socioeconomic factors. Although the accepted paradigm for transmission continues to be inhalation from the environment, provocative reports suggest that person-to-person transmission may occur. A panoply of host factors have been investigated in an effort to elucidate why infection from this bacteria develops in ostensibly immunocompetent patients, and there has been clarification that immunocompetent patients exhibit different histopathology from immunocompromised patients with nontuberculous mycobacteria infection. It is now evident that Mycobacterium abscessus, an increasingly prevalent cause of PNTM lung disease, can be classified into three separate subspecies with differing genetic susceptibility or resistance to macrolides. Recent publications also raise the possibility of improved control of PNTM through enhanced adherence to current treatment guidelines as well as new approaches to treatment and even prevention. These and other recent developments and insights that may inform our approach to PNTM lung disease are reviewed and discussed.

US Cystic Fibrosis Foundation and European Cystic Fibrosis Society consensus recommendations for the management of non-tuberculous mycobacteria in individuals with cystic fibrosis

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental organisms that can cause chronic pulmonary infection, particularly in individuals with pre-existing inflammatory lung disease such as cystic fibrosis (CF). Pulmonary disease caused by NTM has emerged as a major threat to the health of individuals with CF but remains difficult to diagnose and problematic to treat. In response to this challenge, the US Cystic Fibrosis Foundation (CFF) and the European Cystic Fibrosis Society (ECFS) convened an expert panel of specialists to develop consensus recommendations for the screening, investigation, diagnosis and management of NTM pulmonary disease in individuals with CF. Nineteen experts were invited to participate in the recommendation development process. Population, Intervention, Comparison, Outcome (PICO) methodology and systematic literature reviews were employed to inform draft recommendations. An anonymous voting process was used by the committee to reach consensus. All committee members were asked to rate each statement on a scale of: 0, completely disagree, to 9, completely agree; with 80% or more of scores between 7 and 9 being considered ‘good’ agreement. Additionally, the committee solicited feedback from the CF communities in the USA and Europe and considered the feedback in the development of the final recommendation statements. Three rounds of voting were conducted to achieve 80% consensus for each recommendation statement. Through this process, we have generated a series of pragmatic, evidence-based recommendations for the screening, investigation, diagnosis and treatment of NTM infection in individuals with CF as an initial step in optimising management for this challenging condition.

Epidemiology of nontuberculous mycobacteria (NTM) amongst individuals with cystic fibrosis (CF)

BACKGROUND

Infection by nontuberculous mycobacteria (NTM) in patients with cystic fibrosis (CF) is often associated with significant morbidity. Limited, conflicting results are published regarding risk factors for pulmonary NTM disease. We analysed factors potentially associated with NTM in a large population of European patients with CF.

METHODS

We investigated associations between presence of NTM and various factors for patients registered in the European Cystic Fibrosis Society Patient Registry.

RESULTS

374 (2.75%) of 13,593 patients studied had at least one positive NTM culture within the study year. Age- and FEV1-adjusted odds of NTM infection was more than 2.5 times higher (95%CI: 1.79; 3.60) in patients infected by Stenotrophomonas maltophilia than in patients not infected (p<0.0001), 2.36 times higher (95%CI: 1.80;3.08) in patients with ABPA than without (p<0.0001), 1.79 times higher (95%CI: 1.34; 2.38) in patients who use bronchodilators than in patients who don't (p<0.0001), 1.49 times higher (95%CI: 1.18; 1.89) in patients who use inhaled antibiotics than in patients who don't (p=0.001), and 1.30 times higher (95%CI: 1.02; 1.66) in patients who use rhDNase than in patients who don't (p=0.032).

CONCLUSIONS

NTM-positive cultures in individuals with CF are associated with distinct clinical variables. Improved data collection identifying risk factors for NTM infection will allow more focused screening strategies, and influence therapeutic choices and infection control measures in high-risk patients.

Infection in cystic fibrosis: impact of the environment and climate

In many countries numbers of adults with cystic fibrosis (CF) exceed that of children, with median survival predicted to surpass 50 years. Increasing longevity is, in part, due to intensive therapies including eradication of early infection and suppressive therapies and pulmonary exacerbations. Initial infections with common CF pathogens are thought to arise from the natural environment. We review the impact of climate and environment on infection in CF. Specifically, several studies indicate that higher ambient temperatures, proximity to the equator and the summer season may be linked to the increased prevalence of Pseudomonas aeruginosa in people with CF. The environment may also play an important role in the acquisition of Gram negative organisms other than P. aeruginosa. There is emerging data suggesting that climatic and environmental factors are likely to impact on the risk of infection with NTM and fungi in people which are found extensively throughout the natural environment.

Impact of industrial structure and soil exposure on the regional variations in pulmonary nontuberculous mycobacterial disease prevalence

OBJECTIVE/BACKGROUND

The prevalence of pulmonary nontuberculous mycobacterial (pNTM) disease, including Mycobacterium avium complex (MAC), varies widely according to geographic region. However, the factors that influence regional variations in pNTM disease prevalence remain unknown. This study was undertaken to examine whether environmental or occupational factors or host traits could influence regional variations in pNTM disease prevalence.

METHODS

We collected laboratory data on pulmonary tuberculosis (pTB) and pNTM from two hospitals in the West Harima area of Japan and five hospitals in Kyoto City, Japan from 2012 to 2013. We estimated microbiological pNTM disease prevalence by multiplying all pTB cases in each area with the ratio of pNTM cases and pTB cases at the survey hospitals in each area. We administered a standardized questionnaire to 52 patients and 120 patients with pulmonary MAC (pMAC) disease at Ako City Hospital and Kyoto University Hospital, respectively.

RESULTS

The estimated prevalence of microbiological pNTM disease in the West Harima area (85.4/100,000 population-years) was significantly higher than that observed in Kyoto City (23.6/100,000 population-years; p<.001). According to multiple logistic regression analysis, in Ako City Hospital, primary (activities directly related to natural resources) and secondary industries (construction, mining, and manufacturing primary industry produce; odds ratio [OR]=4.79; 95% confidence interval [CI]=1.49-14.0; p=.007) and soil exposure (OR=13.6; 95% CI=4.94-45.26; p<.001) were associated with pMAC disease.

CONCLUSION

Environmental factors, both industrial structures associated with occupational dust and environmental soil exposure, could influence the regional variations in pNTM disease prevalence.

Nontuberculous Mycobacterial Infections in Cystic Fibrosis

Nontuberculous mycobacteria (NTM) are important emerging cystic fibrosis (CF) pathogens, with estimates of prevalence ranging from 6% to 13%. Diagnosis of NTM disease in patients with CF is challenging, as the infection may remain indolent in some, without evidence of clinical consequence, whereas other patients suffer significant morbidity and mortality. Treatment requires prolonged periods of multiple drugs and varies depending on NTM species, resistance pattern, and extent of disease. The development of a disease-specific approach to the diagnosis and treatment of NTM infection in CF patients is a research priority, as a lifelong strategy is needed for this high-risk population.

Pulmonary Nontuberculous Mycobacterial Infection. A Multisystem, Multigenic Disease

RATIONALE

The clinical features of patients infected with pulmonary nontuberculous mycobacteria (PNTM) are well described, but the genetic components of infection susceptibility are not.

OBJECTIVES

To examine genetic variants in patients with PNTM, their unaffected family members, and a control group.

METHODS

Whole-exome sequencing was done on 69 white patients with PNTM and 18 of their white unaffected family members. We performed a candidate gene analysis using immune, cystic fibrosis transmembrance conductance regulator (CFTR), cilia, and connective tissue gene sets. The numbers of patients, family members, and control subjects with variants in each category were compared, as was the average number of variants per person.

MEASUREMENTS AND MAIN RESULTS

A significantly higher number of patients with PNTM than the other subjects had low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue categories (35, 26, 90, and 90%, respectively). Patients with PNTM also had significantly more cilia and connective tissue variants per person than did control subjects (2.47 and 2.55 compared with 1.38 and 1.40, respectively; P = 1.4 × 10(-6) and P = 2.7 × 10(-8), respectively). Patients with PNTM had an average of 5.26 variants across all categories (1.98 in control subjects; P = 2.8 × 10(-17)), and they were more likely than control subjects to have variants in multiple categories. We observed similar results for family members without PNTM infection, with the exception of the immune category.

CONCLUSIONS

Patients with PNTM have more low-frequency, protein-affecting variants in immune, CFTR, cilia, and connective tissue genes than their unaffected family members and control subjects. We propose that PNTM infection is a multigenic disease in which combinations of variants across gene categories, plus environmental exposures, increase susceptibility to the infection.

Hospital costs in the US for pulmonary mycobacterial diseases

BACKGROUND

Pulmonary mycobacterial diseases describe both tuberculosis (TB) and nontuberculous mycobacteria (NTM). Few data are available measuring the cost burden of mycobacterial diseases at the national level. The purpose of this study is to evaluate the cost burden and measure emerging trends in hospitalization of pulmonary TB and NTM cases in the United States from 2001 through 2012.

METHODS

This study is a retrospective, community-based cost analysis of hospitalized patients with a principal diagnosis of pulmonary mycobacterial diseases from 2001 through 2012. Data for pulmonary TB and NTM were retrieved from the Healthcare Cost and Utilization Project (HCUP), US Department of Health and Human Services. The statistical significance of observed trends of NTM and TB national hospital costs was calculated using Poisson log-linear regression.

RESULTS

20,049 hospital discharges were reported for pulmonary NTM and 69,257 for pulmonary TB in the US from 2001 through 2012. The total associated cost of these discharges was $903,767,292 for pulmonary NTM and $2,078,113,317 for pulmonary TB. During the study period, the national hospital costs of pulmonary NTM increased at a statistically significant rate in the US over each year (P = 0.001). However, no such increase was found for national hospital costs of pulmonary TB.

CONCLUSIONS

The national hospital cost of NTM management is increasing. These results emphasize the importance of continued research in pulmonary NTM in order to improve current guidelines in prevention and treatment strategies.

Environmental risks for nontuberculous mycobacteria. Individual exposures and climatic factors in the cystic fibrosis population

RATIONALE

Persons with cystic fibrosis are at high risk of pulmonary nontuberculous mycobacterial infection, with a national prevalence estimated at 13%. The risk of nontuberculous mycobacteria associated with specific environmental exposures, and the correlation with climatic conditions in this population has not been described.

OBJECTIVES

To describe the association of pulmonary nontuberculous mycobacteria with individual exposures to water and soil aerosols, and the population associations of these infections with climatic factors.

METHODS

We conducted a nested case-control study within a cohort study of pulmonary nontuberculous mycobacteria prevalence at 21 geographically diverse national cystic fibrosis centers. Incident nontuberculous mycobacterial infection cases (at least one prior negative culture followed by one positive culture) were age- and sex-matched to culture-negative controls. Exposures to water and soil were assessed by administering a standardized questionnaire. Cohort prevalence at each of the 21 centers was correlated with climatic conditions in the same area through linear regression modeling.

MEASUREMENTS AND MAIN RESULTS

Overall, 48 cases and 85 control subjects were enrolled. Indoor swimming was associated with incident infection (adjusted odds ratio, 5.9, 95% confidence interval, 1.3-26.1), although only nine cases (19%) and five control subjects (6%) reported indoor swimming in the 4 months prior to infection. Exposure to showering and municipal water supply was common among both cases and control subjects: 77% of cases and 76% of control subjects reported showering at least daily. In linear regression, average annual atmospheric water vapor content was significantly predictive of center prevalence (P = 0.0019), with R(2) = 0.40.

CONCLUSIONS

Atmospheric conditions explain more of the variation in disease prevalence than individual behaviors. The risk of specific exposures may vary by geographic region due to differences in conditions favoring mycobacterial growth and survival. However, because exposure to these organisms is ubiquitous and behaviors are similar among persons with and without pulmonary nontuberculous mycobacteria, genetic susceptibility beyond cystic fibrosis is likely to be important for disease development. Common individual risk factors in high-risk populations remain to be identified.

Epidemiology and clinical features of pulmonary nontuberculous mycobacteriosis in Nagasaki, Japan

BACKGROUND AND OBJECTIVES

Recent reports indicate that the incidence of nontuberculous mycobacterial-lung disease (NTM-LD) is increasing. This study aimed to investigate the epidemiology and clinical features of NTM-LD patients in Nagasaki prefecture, Japan to identify the negative prognostic factors for NTM-LD in Japan.

METHODS

The medical records of patients newly diagnosed with NTM-LD in eleven hospitals in Nagasaki prefecture between January 2001 and February 2010 were reviewed. Data regarding the annual population of each region and the incidence of all forms of tuberculosis were collected to assess geographic variations in NTM-LD incidence, isolates, and radiological features.

RESULTS

A total 975 patients were diagnosed with NTM-LD. The incidence increased over the study period and reached 11.0 and 10.1 per 100,000 population in 2008 and 2009, respectively. M. intracellulare was the most common pathogen in the southern region, and M. avium most common in other regions. The most common radiographic pattern was the nodular-bronchiectatic pattern. Age >60 years, body mass index <18.5 kg/m2, underlying lung disease, and cavitary pattern were the negative prognostic factors at the 1-year follow-up.

CONCLUSIONS

The incidence of NTM-LD has been increasing in Nagasaki prefecture. The isolates and radiographic features of patients vary markedly by region.

Natural disasters and nontuberculous mycobacteria: a recipe for increased disease?

Infectious diseases acquired by survivors of large-scale natural disasters complicate the recovery process. During events such as tsunamis, hurricanes, earthquakes, and tornados and well into the recovery period, victims often are exposed to water-soil mixtures that have relocated with indigenous microbes. Because nontuberculous mycobacteria (NTM) are ubiquitous in water and soil, there is potential for increased exposure to these organisms during natural disasters. In this hypothesis-driven commentary, we discuss the rise in NTM lung disease and natural disasters and examine the geographic overlap of NTM infections and disaster frequencies in the United States. Moreover, we show an increased number of positive NTM cultures from Louisiana residents in the years following three of the relatively recent epic hurricanes and posit that such natural disasters may help to drive the increased number of NTM infections. Finally, we advocate for increased environmental studies and surveillance of NTM infections before and after natural disasters.

Mycobacterium avium complex (MAC) presenting as the first infection in a child with cystic fibrosis

Nontuberculous mycobacteria (NTM) have been increasingly recognized in recent years as contributors to clinically significant lung infection in cystic fibrosis (CF) patients. Reports of prevalence vary from 6 to 22% around the world. Prevalence estimates in childhood CF is challenging since sputum producers are rare, bronchoalveolar lavage is an invasive procedure and may not be feasible, and mounting evidence deeming throat cultures to be unsuccessful in detecting NTM. We report a case of an overall healthy 13 year old young adolescent female with CF, who presented with Mycobacterium avium complex (MAC) as her first documented lung infection, and while only presenting with minor cough proved to have severe purulent bronchial infection. Contrary to common paradigms, NTM can be the first infection in a non-previously infected airway, and, this first infection can be of a serious nature unlike the more subtle anticipated pattern. The causes of the high and probably increasing overall incidence of NTM and specifically in CF elude explanation and mandate further study. Continuing efforts should be invested into the study of all aspects of this ominous infection. Pediatr Pulmonol. 2015; 50:E5-E7. © 2014 Wiley Periodicals, Inc.

Environmental sources of nontuberculous mycobacteria

Nontuberculous mycobacteria (NTM) include over 150 species. The source for human infection is the environment. NTM are normal inhabitants of soil and drinking water. NTM grow and persist in many buildings. They are not contaminants of drinking water, but members of the natural drinking water microbial population. Infection occurs because humans share the same habitats. Because the ecology, antibiotic susceptibility, and virulence of individual species differs, identifying NTM isolates to species is important. Treatment requires multiple antibiotics. NTM patients are innately sensitive to NTM infection, resulting in reinfection. Knowledge of the sources of NTM can reduce exposure to environmental NTM.

Epidemiology of human pulmonary infection with nontuberculous mycobacteria: a review

Population-based data have documented a worldwide increase in the prevalence of human nontuberculous mycobacterial (NTM) infections since 2000. Mycobacterium avium complex is predominant in North America and East Asia, whereas in regions within Europe, M kansasii, M xenopi, and M malmoense are more common. Host factors important to the current epidemiology of NTM pulmonary disease include thoracic skeletal abnormalities, rheumatoid arthritis, and use of immunomodulatory drugs. Clustering of disease within families suggests a heritable genetic predisposition to disease susceptibility. Warm, humid environments with high atmospheric vapor pressure contribute to population risk.

Nontuberculous mycobacteria among patients with cystic fibrosis in the United States: screening practices and environmental risk

RATIONALE

Persons with cystic fibrosis (CF) are at greater risk of nontuberculous mycobacterial (NTM) infections than the general population. However, among patients with CF, geographic variation in prevalence is poorly understood.

OBJECTIVES

To describe the prevalence and screening practices of NTM among U.S. patients with CF.

METHODS

CF Patient Registry data from 2010-2011 were obtained to estimate the prevalence of NTM among patients with CF 12 years of age or older by state. Climatic data were also obtained and predictors of NTM infection analyzed using regression analysis. Geographic clustering and mycobacterial culture rates by state were also assessed.

MEASUREMENTS AND MAIN RESULTS

Among patients with CF 12 years of age or older, 58% had mycobacterial cultures; 14% were positive for NTM. Most states (n = 31) had a prevalence of 10-20%; seven states predominantly in the West and Southeast had a prevalence of 20% or greater, including Alaska, which cultured patients more frequently than any other state. Nearly 60% of positive cultures were for Mycobacterium avium complex, although this ranged by state, from 29% in Louisiana to 100% for Nebraska/Delaware. Significant (P < 0.002) spatial clustering of NTM was detected, centering in Wisconsin, Arizona, Florida, and Maryland. Higher saturated vapor pressure increased risk for NTM (odds ratio = 1.06; 95% confidence interval = 1.02-1.10). The proportion of patients cultured for mycobacteria varied greatly by state of residence (median = 46%; range = 9-73%).

CONCLUSIONS

NTM prevalence varies significantly among patients with CF by geographic area, and is largely influenced by environmental factors. However, NTM culture practices vary greatly, with some high-prevalence states screening less than 25% annually. Routine screening for all patients with CF is needed for timely detection.

Managing pulmonary nontuberculous mycobacterial infection. time for a patient-centered approach

The incidence of nontuberculous mycobacteria is increasing worldwide. However, the evidence base for clinical management comprises mostly expert opinion, case series, and few randomized clinical trials. Most currently recommended treatment regimens entail prolonged use of multiple antimicrobial agents associated with multiple self-limited and persistent potential adverse effects, including irreversible impairments of hearing, vision, and kidney function. Yet, little is known about how treatment impacts an individual patient's overall health status. Current treatment guidelines, although of undoubted value, are constrained by these limitations. Here we call for new studies that reassess recommendations for medical management of pulmonary nontuberculous mycobacteria infections, in particular Mycobacterium avium-intracellulare complex and Mycobacterium abscessus complex. We propose pragmatic, person-centered outcome measures that might be used in clinical assessments and new research studies, including patient-reported experience measures and patient-reported outcome measures. This will enable patients and their health-care providers to make clinical management decisions that derive from a realistic view of what they can hope to achieve from treatment.

Highlight on advances in nontuberculous mycobacterial disease in North America

Nontuberculous mycobacteria (NTM) are ubiquitous in the environment and exist as an important cause of pulmonary infections in humans. Pulmonary involvement is the most common disease manifestation of NTM and the incidence of NTM is growing in North America. Susceptibility to NTM infection is incompletely understood; therefore preventative tools are not well defined. Treatment of pulmonary nontuberculous mycobacterial (NTM) infection is difficult and entails multiple antibiotics and an extended treatment course. Also, there is a considerable variation in treatment management that should be considered before initiating treatment. We highlight the new findings in the epidemiology diagnosis and treatment of mycobacterial infections. We debate new advances regarding NTM infection in cystic fibrosis patients and solid organ transplant recipients. Finally, we introduce a new epidemiologic model for NTM disease based on virulence-exposure-host factors.

Frequency and clinical significance of respiratory isolates of non-tuberculous mycobacteria in Riyadh, Saudi Arabia

BACKGROUND AND AIMS

The prevalence of pulmonary non-tuberculous mycobacteria (NTM) disease is increasing worldwide. The aim of this study was to assess the frequency and clinical significance of NTM isolated from respiratory specimens at King Abdul-Aziz Medical City-Riyadh, Saudi Arabia.

METHODS

The medical records of all patients who had at least one respiratory specimen that was positive for growth of NTM between 2006 and 2012 were retrospectively reviewed. The clinical significance of the isolates was determined using the diagnostic criteria for NTM disease published by the American Thoracic Society (ATS).

RESULT

A total of 380 respiratory specimens with positive culture for NTM from 142 patients were identified. Forty patients (28%) had definite pulmonary NTM disease with a mean (± standard deviation) age of 54 ± 16 years, 58% were male and 50% had had underlying chronic lung disease. Mycobacterium avium complex (MAC) (n = 19, 48%) and Mycobacterium abscessus (n = 10, 25%) were the most commonly encountered NTM. The clinical manifestations of NTM lung disease are non-specific, with symptoms indistinguishable from pulmonary tuberculosis (TB). The most common radiological features of NTM lung disease were nodular bronchiectasis (45%) and fibrocavitary lesions (40%).

CONCLUSIONS

Twenty-eight percent of the patients with NTM isolates met the ATS diagnostic criteria for NTM lung disease. MAC and M. abscessus were the most encountered NTM isolated species that caused NTM lung disease in our population, which is a rate similar to many previous studies.

Non-tuberculous mycobacterial infections at San Francisco General Hospital

BACKGROUND AND AIMS

The epidemiology of non-tuberculous mycobacteria (NTM) infection is not well defined. We evaluated the trends in incidence of NTM infections at San Francisco General Hospital (SFGH), a large metropolitan county hospital.

METHODS

We performed a retrospective review of microbiologic and clinical records of all patients with a positive NTM culture reported from 1993 to 2001. NTM infection was defined by the isolation of >1 NTM from any clinical specimen. Patients were stratified by human immunodeficiency virus (HIV) status. Univariate and multivariate logistic regression were used to identify factors that were independently associated with NTM infection. Trends over time were assessed using Poisson test for trend.

RESULTS

During the study period, 25 736 samples from 7395 patients were cultured for mycobacteria. Of these samples, 2853 (11.1%) from 1345 patients (18.2%) were culture positive for NTM. Patient characteristics associated with infection included younger age (P < 0.001), male gender (P < 0.001), White ethnicity compared with Asian and Hispanic (P < 0.001 and P = 0.01, respectively), and HIV positivity (P < 0.001). Overall, NTM infection at SFGH decreased significantly from 319 cases in 1993 to 59 in 2001 (P < 0.001). Mycobacterium avium was predominant in both HIV-positive and HIV-negative populations (74.5% and 44.6% of isolates, respectively), and Mycobacterium kansasii was the second most common NTM species isolated. The proportion of other NTM species isolated in these groups differed.

CONCLUSION

In contrast to other published studies, time-series analyses show that NTM isolation rates decreased during the study period at SFGH, where NTM was most strongly associated with HIV infection.

A spatial epidemiological analysis of nontuberculous mycobacterial infections in Queensland, Australia

BACKGROUND

The epidemiology of infections with nontuberculous mycobacteria (NTM) has been changing and the incidence has been increasing in some settings. The main route of transmission to humans is considered to be from the environment. We aimed to describe spatial clusters of cases of NTM infections and to identify associated climatic, environmental and socio-economic variables.

METHODS

NTM data were obtained from the Queensland Mycobacterial Reference Laboratory for the period 2001-2011. A Bayesian spatial conditional autoregressive model was constructed at the postcode level, with covariates including soil variables, maximum, mean and minimum rainfall and temperature, income (proportion of population earning < $32,000 and < $52,000) and land use category.

RESULTS

Significant clusters of NTM infection were identified in the central Queensland region overlying the Surat sub-division of the Great Artesian Basin, as well as in the lower North Queensland Local Government Area known as the Whitsunday region. Our models estimated an expected increase of 21% per percentage increase of population earning < $52,000 (95% CI 9-34%) and an expected decrease of 13% for every metre increase of average topsoil depth for risk of Mycobacterium intracellulare infection (95% CI -3 - -22%). There was an estimated increase of 79% per mg/m3 increase of soil bulk density (95% CI 26-156%) and 19% decrease for every percentage increase in population earning < $32,000 for risk of M. kansasii infection (95% CI -3 - -49%).

CONCLUSIONS

There were distinct spatial clusters of M. kansasii, M. intracellulare and M. abscessus infections in Queensland, and a number of socio-ecological, economic and environmental factors were found to be associated with NTM infection risk.

Reducing human exposure to Mycobacterium avium

In light of the increasing prevalence of Mycobacterium avium pulmonary disease and the challenges of treating patients with M. avium infection, consideration of measures to reduce exposure is warranted. Because M. avium inhabits water and soil, humans are surrounded by that opportunistic pathogen. Because infection has been linked to the presence of M. avium in household plumbing, increasing hot water temperature, reducing aerosol (mist) exposures in bathrooms and showers, and installing filters that prevent the passage of mycobacteria will likely reduce M. avium exposure. Granular activated carbon (charcoal) filters support the growth of M. avium and should be avoided. When gardening, avoid the inhalation of soil dusts by using a mask or wetting the soil because peat-rich potting soils have high numbers of mycobacteria.

Update in tuberculosis and nontuberculous mycobacterial disease 2012

In 2012, new publications in the Journal described both the predictive value of the new IFN-γ release assays for diagnosis of latent tuberculosis (TB), but also provided evidence that these new tests cannot be interpreted simply as positive or negative, as initially hoped. Surgical masks can reduce transmission of TB infection, but other measures such as state-wide implementation of targeted testing and treatment of latent TB or active case finding require substantial and sustained effort to successfully reduce TB morbidity and mortality. A quasiexperimental study revealed that a package of social interventions could substantially reduce risk of TB disease in heavily exposed (and infected) children in the preantibiotic era. A study in a high-TB burden setting suggested that a new rapid drug-susceptibility test for TB may be more practical for implementation than traditional culture-based phenotypic tests. And two studies of TB vaccines revealed that currently used bacillus Calmette-Guérin strains vary in their ability to affect correlates of immunogenicity, whereas a new candidate vaccine, MVA85A, was safe and immunogenic in adults. Studies of nontuberculous mycobacteria (NTM) described a rapid rise in the prevalence and spatial clustering of NTM in the United States over the past decade. Although risk factors for pulmonary NTM such as advanced age and low BMI are known, the mechanisms underlying infection and disease remain mysterious. Four studies of therapy of NTM disease highlighted the pressing need for well-designed international randomized controlled trials to improve our management of NTM disease.

Bedfellows: mycobacteria and rheumatoid arthritis in the era of biologic therapy

In modern times a relationship between tuberculosis (TB) and rheumatoid arthritis (RA) has been firmly recognized, and is primarily attributable to the immunosuppressive therapies used to treat RA. Whereas TB can complicate the successful management of RA, nontuberculous mycobacteria have now perhaps become as important as (if not more so than) TB in the setting of RA, and can represent an even greater challenge to the rheumatologist wishing to use immunosuppressive therapies. This article reviews our most recent understanding of the epidemiological and clinical aspects of mycobacterial disease as it relates to RA, and the existing and emerging immunosuppressive therapies used to treat this disease.

Pulmonary disease caused by nontuberculous mycobacteria

The propensity of various nontuberculous mycobacteria to cause lung disease varies widely and is conditioned by host factors; infection is believed to occur from environmental sources. Nontuberculous mycobacteria pulmonary disease (PNTM) is increasing worldwide and Mycobacterium avium complex is the most common cause. PNTM usually occurs in one of three prototypical forms: hypersensitivity pneumonitis, cavitary tuberculosis-like disease or nodular bronchiectasis. PNTM has been linked in some patients to genetic variants of the cystic fibrosis transmembrane conductance regulator gene and a distinct patient phenotype. Interactions between PNTM and other comorbidities are also increasingly appreciated. Guidelines for diagnosis, emphasizing chest imaging and microbiology, have been published; speciation using molecular techniques is critical for accuracy and for treatment decisions. Clinical trials are lacking to inform treatment for many species and experience with M. avium complex and several others species serves as a guide instead. Use of multiple drugs for a period of at least 12 months following sputum conversion is the norm for most species. In vitro drug susceptibility results for many drugs may not correlate with clinical outcomes and such testing should be done on a selective basis.

Burden and trends of hospitalisations associated with pulmonary non-tuberculous mycobacterial infections in Germany, 2005-2011

BACKGROUND

Representative population-based data on the epidemiology of pulmonary non-tuberculous mycobacterial (PNTM) infections in Europe are limited. However, these data are needed in order to optimise patient care and to facilitate the allocation of healthcare resources. The aim of the present study was to investigate the current burden and the trends of PNTM infection-associated hospitalisations in Germany.

METHODS

International Classification of Diseases, 10th revision (ICD-10) discharge diagnosis codes were extracted from the official nationwide diagnosis-related groups (DRG) hospital statistics in order to identify PNTM infection-associated hospitalisations (ICD-10 code A31.0) between 2005 and 2011. Poisson log-linear regression analysis was used to assess the significance of trends.

RESULTS

Overall, 5,959 records with PNTM infection as any hospital discharge diagnosis were extracted from more than 125 million hospitalisations. The average annual age-adjusted rate was 0.91 hospitalisations per 100,000 population. Hospitalisation rates increased during the study period for both males and females, with the highest rate of 3.0 hospitalisations per 100,000 population among elderly men, but the most pronounced average increase of 6.4%/year among females, particularly those of young and middle age, and hospitalisations associated with cystic fibrosis. Overall, chronic obstructive pulmonary disease (COPD) was the most frequent PNTM infection-associated condition in 28.9% of hospitalisations and also showed a significant average annual increase of 4.8%.

CONCLUSIONS

The prevalence of PNTM infection-associated hospitalisations is steadily increasing in Germany. COPD is currently the most important associated condition. Our population-based study provides evidence of a changing epidemiology of PNTM infections and highlights emerging clinical implications.

Plumbing of hospital premises is a reservoir for opportunistically pathogenic microorganisms: a review

Several bacterial species that are natural inhabitants of potable water distribution system biofilms are opportunistic pathogens important to sensitive patients in healthcare facilities. Waterborne healthcare-associated infections (HAI) may occur during the many uses of potable water in the healthcare environment. Prevention of infection is made more challenging by lack of data on infection rate and gaps in understanding of the ecology, virulence, and infectious dose of these opportunistic pathogens. Some healthcare facilities have been successful in reducing infections by following current water safety guidelines. This review describes several infections, and remediation steps that have been implemented to reduce waterborne HAIs.

Spatial clusters of nontuberculous mycobacterial lung disease in the United States

RATIONALE

Prevalence of pulmonary nontuberculous mycobacterial (PNTM) disease varies by geographic region, yet the factors driving these differences remain largely unknown.

OBJECTIVES

To identify spatial clusters of PNTM disease at the county level and to describe environmental and sociodemographic factors predictive of disease.

METHODS

PNTM cases identified from a nationally representative sample of Medicare Part B beneficiaries from 1997 to 2007 were geocoded by county and state of residence. County-level PNTM case counts and Medicare population data were then uploaded into SaTScan to identify significant spatial clusters and low-risk areas of disease. High-risk and low-risk counties were then compared to identify significant sociodemographic and environmental differences.

MEASUREMENTS AND MAIN RESULTS

We identified seven significant (P < 0.05) clusters of PNTM cases. These high-risk areas encompassed 55 counties in 8 states, including parts of California, Florida, Hawaii, Louisiana, New York, Oklahoma, Pennsylvania, and Wisconsin. Five low-risk areas were also identified, which encompassed 746 counties in 23 states, mostly in the Midwest. Counties in high-risk areas were significantly larger, had greater population densities, and higher education and income levels than low-risk counties. High-risk counties also had higher mean daily potential evapotranspiration levels and percentages covered by surface water, and were more likely to have greater copper and sodium levels in the soil, although lower manganese levels.

CONCLUSIONS

Specific environmental factors related to soil and water exposure appear to increase the risk of PNTM infection. Still, given that environmental sources of NTM are ubiquitous and PNTM disease is rare, both host susceptibility and environmental factors must be considered in explaining disease development.