Season is associated with Pseudomonas aeruginosa acquisition in young children with cystic fibrosis

Acute exposure to realistic simulated urban atmospheres exacerbates pulmonary phenotype in cystic fibrosis-like mice

Cystic Fibrosis (CF) is a lethal genetic disorder caused by pathogenic mutations of the CFTR gene. CF patients show a high phenotypic variability of unknown origin. In this context, the present study was therefore dedicated to investigating the effects of acute exposure to air pollution on the pulmonary morbidity of a CF-like mice model. To achieve our aim, we developed a multidisciplinary approach and designed an innovative protocol using a simulation chamber reproducing multiphasic chemical processes at the laboratory. A particular attention was paid to modulate the composition of these simulated atmospheres, in terms of concentrations of gaseous and particulate pollutants. Exposure to simulated urban atmospheres induced mucus secretion and increased inflammatory biomarkers levels, oxidative stress as well as expression of lung remodeling actors in both WT and CF-like mice. The latter were more susceptible to develop such a response. Though we could not establish direct mechanistic link between biological responses and specific components, the type of immune response induced depended on the chemical composition of the atmospheres. Overall, we demonstrated that air pollution is an important determinant of CF-like lung phenotypic variability and emphasized the added value of considering air pollution with a multi-pollutant approach.

Urbanization influences the indoor transfer of airborne antibiotic resistance genes, which has a seasonally dependent pattern

Over the last few years, the cumulative use of antibiotics in healthcare institutions, as well as the rearing of livestock and poultry, has resulted in the accumulation of antibiotic resistance genes (ARGs). This presents a substantial danger to human health worldwide. The characteristics of airborne ARGs, especially those transferred from outdoors to indoors, remains largely unexplored in neighborhoods, even though a majority of human population spends most of their time there. We investigated airborne ARGs and mobile genetic element (MGE, IntI1), plant communities, and airborne microbiota transferred indoors, as well as respiratory disease (RD) prevalence using a combination of metabarcode sequencing, real-time quantitative PCR and questionnaires in 72 neighborhoods in Shanghai. We hypothesized that (i) urbanization regulates ARGs abundance, (ii) the urbanization effect on ARGs varies seasonally, and (iii) land use types are associated with ARGs abundance. Supporting these hypotheses, during the warm season, the abundance of ARGs in peri-urban areas was higher than in urban areas. The abundance of ARGs was also affected by the surrounding land use and plant communities: an increase in the proportion of gray infrastructure (e.g., residential area) around neighborhoods can lead to an increase in some ARGs (mecA, qnrA, ermB and mexD). Additionally, there were variations observed in the relationship between ARGs and bacterial genera in different seasons. Specifically, Stenotrophomonas and Campylobacter were positively correlated with vanA during warm seasons, whereas Pseudomonas, Bacteroides, Treponema and Stenotrophomonas positively correlated with tetX in the cold season. Interstingly, a noteworthy positive correlation was observed between the abundance of vanA and the occurrence of both rhinitis and rhinoconjunctivitis. Taken together, our study underlines the importance of urbanization and season in controlling the indoor transfer of airborne ARGs. Furthermore, we also highlight the augmentation of green-blue infrastructure in urban environments has the potential to mitigate an excess of ARGs.

Anti-Pseudomonas aeruginosa Vaccines and Therapies: An Assessment of Clinical Trials

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes high morbidity and mortality in cystic fibrosis (CF) and immunocompromised patients, including patients with ventilator-associated pneumonia (VAP), severely burned patients, and patients with surgical wounds. Due to the intrinsic and extrinsic antibiotic resistance mechanisms, the ability to produce several cell-associated and extracellular virulence factors, and the capacity to adapt to several environmental conditions, eradicating P. aeruginosa within infected patients is difficult. Pseudomonas aeruginosa is one of the six multi-drug-resistant pathogens (ESKAPE) considered by the World Health Organization (WHO) as an entire group for which the development of novel antibiotics is urgently needed. In the United States (US) and within the last several years, P. aeruginosa caused 27% of deaths and approximately USD 767 million annually in health-care costs. Several P. aeruginosa therapies, including new antimicrobial agents, derivatives of existing antibiotics, novel antimicrobial agents such as bacteriophages and their chelators, potential vaccines targeting specific virulence factors, and immunotherapies have been developed. Within the last 2-3 decades, the efficacy of these different treatments was tested in clinical and preclinical trials. Despite these trials, no P. aeruginosa treatment is currently approved or available. In this review, we examined several of these clinicals, specifically those designed to combat P. aeruginosa infections in CF patients, patients with P. aeruginosa VAP, and P. aeruginosa-infected burn patients.

Effect of daily chlorhexidine bathing on reducing infections caused by multidrug-resistant organisms in intensive care unit patients: A semiexperimental study with parallel controls

OBJECTIVE

To assess the effectiveness of daily bathing by chlorhexidine bathing on multidrug-resistant organisms in ICU, especially on carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), and carbapenem-resistant Enterobacteriaceae (CRE).

METHODS

Semiexperimental study which employed both precontrols and a parallel control was conducted. In the intervention period (from July 1 to December 31, 2016), strengthened infection control measures and daily bathing with 2% CHG-impregnated wipes once daily was performed in the ICU. Fifty-seven non-ICU wards with the occurrence of multidrug-resistant organisms (MDRO) infections during the same time were selected as parallel control group (only CHG bathing was not performed). The net effect of the 2% CHG daily bathing was evaluated by the difference in difference (DID) model.

RESULTS

The DID model analysis showed that CHG bathing reduced the incidence of CRAB- and CRPA-caused infections in ICU by 1.56 and 2.15 cases/1000 patient days, and bathing of every 19 patients (95CI% 13 to 41) and 39 patients (95CI% 24 to 110) were able to prevent one case of HAIs of total MDROs and CRPA, respectively. However, CHG bathing showed no effect on MRSA, VRE, and CRE (p > 0.05).

CONCLUSION

Daily bathing with 2% CHG-impregnated wipes can reduce HAIs caused by CRAB and CRPA, while it is not effective for the prevalence of infections caused by MRSA, VRE, and CRE.

Predicting risk-adjusted incidence rates of methicillin-resistant Staphylococcus Aureus and Pseudomonas Aeruginosa in cystic fibrosis programs in the United States

BACKGROUND

Healthcare-associated transmission of methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa occurs for people with cystic fibrosis (CF), but CF programs lack a process to monitor incidence rates (IRs). We assessed predictors of incident infections and created a model to determine risk-adjusted IRs for CF programs.

METHODS

Using the CF Foundation Patient Registry data for all patients from 2012 to 2015, coefficients for variables that predicted IRs were estimated. Hazard functions were then used to predict IRs of MRSA and P. aeruginosa for CF programs based on their patient and program characteristics. Predicted IRs were compared with observed IRs over multiple time intervals.

RESULTS

Multiple patient and program characteristics were identified as predictors of observed IRs. Our model's predicted IRs closely aligned with observed IRs for most CF programs. Alarm values (defined as observed IR > 95% confidence interval of predicted IR) were found at 5.9%, 5.9%, 6.0% (adult, pediatric, affiliate) of programs for MRSA and 3.0%, 1.7%, 0.0% (adult, pediatric, affiliate) of programs for P. aeruginosa.

CONCLUSIONS

We found patient and program characteristics that predicted MRSA and P. aeruginosa IRs. Our model accurately predicted risk-adjusted IRs of MRSA and P. aeruginosa. CF programs could use our model to monitor their IRs and potentially improve infection prevention and control.

The Impact of Air Pollution on the Course of Cystic Fibrosis: A Review

Cystic fibrosis (CF) is a lethal and widespread autosomal recessive disorder affecting over 80,000 people worldwide. It is caused by mutations of the CFTR gene, which encodes an epithelial anion channel. CF is characterized by a great phenotypic variability which is currently not fully understood. Although CF is genetically determined, the course of the disease might also depend on multiple other factors. Air pollution, whose effects on health and contribution to respiratory diseases are well established, is one environmental factor suspected to modulate the disease severity and influence the lung phenotype of CF patients. This is of particular interest as pulmonary failure is the primary cause of death in CF. The present review discusses current knowledge on the impact of air pollution on CF pathogenesis and aims to explore the underlying cellular and biological mechanisms involved in these effects.

Meteorological Factors Influence the Presence of Fungi in the Air; A 14-Month Surveillance Study at an Adult Cystic Fibrosis Center

Background

Cystic fibrosis is an inherited disease that predisposes to progressive lung damage. Cystic fibrosis patients are particularly prone to developing pulmonary infections. Fungal species are commonly isolated in lower airway samples from patients with cystic fibrosis. Fungal spores are prevalent in the air.

Methods

We performed environmental air sampling surveillance at the Manchester Adult Cystic Fibrosis Centre, UK (MACFC) over a 14-month period to assess fungal growth inside and outside the CF center.

Results

Airborne counts of fungal spores peaked from May to October, both in outdoor and indoor samples. Collection of meteorological data allowed us to correlate fungal presence in the air with elevated temperatures and low wind speeds. Additionally, we demonstrated patient rooms containing windows had elevated fungal counts compared to rooms not directly connected to the outdoors.

Conclusions

This study suggests that airborne Aspergillus fumigatus spores were more abundant during the summer months of the survey period, which appeared to be driven by increased temperatures and lower wind speeds. Indoor counts directly correlated to outdoor A. fumigatus levels and were elevated in patient rooms that were directly connected to the outdoor environment via an openable window designed for ventilation purposes. Further studies are required to determine the clinical implications of these findings for cystic fibrosis patients who are predisposed to Aspergillus related diseases, and in particular whether there is seasonal influence on incidence of Aspergillus related conditions and if screening for such complications such be increased during summer months and precautions intensified for those with a known history of Aspergillus related disease.

Impact of Climate Change on Eye Diseases and Associated Economical Costs

Climate change generates negative impacts on human health. However, little is known about specific impacts on eye diseases, especially in arid and semi-arid areas where increases in air temperatures are expected. Therefore, the main goals of this research are: (i) to highlight the association between common eye diseases and environmental factors; and (ii) to analyze, through the available literature, the health expenditure involved in combating these diseases and the savings from mitigating the environmental factors that aggravate them. Mixed methods were used to assess the cross-variables (environmental factors, eye diseases, health costs). Considering Southern Spain as an example, our results showed that areas with similar climatic conditions could increase eye diseases due to a sustained increase in temperatures and torrential rains, among other factors. We highlight that an increase in eye diseases in Southern Spain is conditioned by the effects of climate change by up to 36.5%; the economic burden of the main eye diseases, extrapolated to the rest of the country, would represent an annual burden of 0.7% of Spain’s Gross Domestic Product. In conclusion, the increase in eye diseases has a strong economic and social impact that could be reduced with proper management of the effects of climate change. We propose a new concept: disease sink, defined as any climate change mitigation action which reduces the incidence or morbidity of disease.

Environmental risks of Pseudomonas aeruginosa-What to advise patients and parents

Pseudomonas aeruginosa (PsA) is commonly found in soil and water so is impossible to avoid completely. Parents/carers of children with cystic fibrosis (CF) are concerned about them acquiring PsA from the environment, and different families view risk differently. Our ethos is to enable children with CF to take part as much as possible in educational and fun home activities, in order to maintain their quality of life (and their family's), and not have them feel different from other children. This review presents advice for families as to what they must definitely avoid, what they must take precautions with but can allow, and what they must not avoid. It is mostly evidence-based, but where evidence is lacking it a consensus view from the Paediatric CF Unit at the Royal Brompton Hospital.

Risk Factors for Carbapenem-Resistant Pseudomonas aeruginosa, Zhejiang Province, China

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is a public health concern worldwide, but comprehensive analysis of risk factors for CRPA remains limited in China. We conducted a retrospective observational study of carbapenem resistance in 71,880 P. aeruginosa isolates collected in Zhejiang Province during 2015–2017. We analyzed risk factors for CRPA, including the type of clinical specimen; the year, season, and region in which it was collected; patient information, including age, whether they were an outpatient or inpatient, and whether inpatients were in the intensive care unit or general ward; and the level of hospital submitting isolates. We found CRPA was more prevalent among isolates from patients >60 years of age and in inpatients, especially in intensive care units. In addition, specimen types and seasons in which they were collected were associated with higher rates of CRPA. Our findings can help hospitals reduce the spread of P. aeruginosa and optimize antimicrobial drug use.

Influences of environmental exposures on individuals living with cystic fibrosis

INTRODUCTION

Natural, social, and constructed environments play a critical role in the development and exacerbation of respiratory diseases. However, less is known regarding the influence of these environmental/community risk factors on the health of individuals living with cystic fibrosis (CF), compared to other pulmonary disorders.

AREAS COVERED

Here, we review current knowledge of environmental exposures related to CF, which suggests that environmental/community risk factors do interact with the respiratory tract to affect outcomes. Studies discussed in this review were identified in PubMed between March 2019 and March 2020. Although the limited data available do not suggest that avoiding potentially detrimental exposures other than secondhand smoke could improve outcomes, additional research incorporating novel markers of environmental exposures and community characteristics obtained at localized levels is needed.

EXPERT OPINION

As we outline, some environmental exposures and community characteristics are modifiable; if not by the individual, then by policy. We recommend a variety of strategies to advance understanding of environmental influences on CF disease progression.

Respiratory viral infections in Western Australians with cystic fibrosis

BACKGROUND

Viral respiratory infections (VRI) in people living with Cystic fibrosis (CF) is less well understood than respiratory bacterial infections, particularly adults with CF and few studies have compared children with adults. This study evaluated the frequency of respiratory viruses in patients with cystic fibrosis (CF) in Western Australia (WA). We determined the VRI in CF and compared them with non-CF patients. Further, we compared CF patients that were hospitalised with those that were not.

PATIENTS/METHODS

Nucleic acid from sputum of 157 CF and 348 non-CF patients was analysed for influenzavirus A (Flu A) and B, (Flu B), respiratory syncytial virus (RSV), human metapneumovirus (hMPV), human rhinovirus (RV), and parainfluenza viruses (PIV 1-3) by RT-PCR, during the 2016 winter respiratory season.

RESULTS

No significant difference in the frequency of respiratory virus detection between CF and non-CF patients was found. RV was the most frequently detected virus in CF patients, and in hospitalised CF. RSV and hMPV were found less frequently in CF patients and RSV was not found in any hospitalised CF patient. A trend for fewer influenzavirus detections in adult CF patients was observed, however the trend was opposite for paediatric patients. RV and Flu A were the most common viruses detected in hospitalised CF patients.

CONCLUSION

There was no significant difference in VRI between CF and non-CF patients. RV and influenza A were most commonly found in hospitalised CF patients, suggesting that infection with these viruses may contribute to hospitalisation for CF respiratory exacerbations.

Treatments for preventing recurrence of infection with Pseudomonas aeruginosa in people with cystic fibrosis

BACKGROUND

Chronic infection with Pseudomonas aeruginosa (PA) in cystic fibrosis (CF) is a source of much morbidity and mortality. Eradication of early PA infection is possible, but can recur in many individuals. We sought to examine strategies to delay the time to PA recurrence in people with CF.

OBJECTIVES

To establish whether secondary prevention strategies, using antibiotics or other therapies, increase the chances of people with CF remaining free from PA infection following successful eradication therapy.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. We also searched ongoing trials registries and the reference lists of relevant articles and reviews. Date of last search: 21 August 2019.

SELECTION CRITERIA

Randomised controlled trials (and quasi-randomised trials where the risk of bias was low) comparing any treatment modality aimed at preventing recurrence of PA infection with placebo, standard therapy or any other treatment modality in people with CF who have undergone successful eradication of PA.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias. Quality of the evidence was assessed using GRADE. Conflicts were resolved by discussion and the opinion of a third review author was sought where necessary. Only a subset of participants in the included trial were eligible, therefore individual participant data were requested and obtained from the trial investigators.

MAIN RESULTS

We included one trial (n = 306) in the review; however, only 253 participants had undergone successful eradication of PA, so fulfilling the inclusion criteria for our review. Information presented relates only to the included subset of participants. The trial recruited children aged one to 12 years (mean (standard deviation (SD)) age of 5.8 (3.5) years), 129 participants (51.0%) were female and the median follow-up was 494 days. We compared cycled therapy with tobramycin inhalation solution (TIS), in which participants underwent 28 days of TIS every three months, with culture-based therapy, in which participants were only prescribed medication when a quarterly sputum sample was positive for PA. Reasons for downgrading the quality of the evidence included applicability (only included children), incomplete outcome data and a small number of participants. The time to next isolation of PA was probably shorter with cycled TIS therapy than with culture-based therapy, hazard ratio (HR) 2.04 days (95% confidence interval (CI) 1.28 to 3.26) (moderate-quality evidence). This is in contrast to the main publication of the only included trial, which examined rate of PA positivity rather than time to PA infection and included participants not eligible for inclusion in this review. At the end of the trial, there was no difference between the cycled and culture-based groups in the change from baseline in forced expiratory volume in one second (FEV₁) L, mean difference (MD) 0.0 L (95% CI -0.09 to 0.09) or in FEV₁ % predicted, MD 0.70% (95% CI -4.33 to 5.73) (both very low-quality evidence). There was no difference in the change from baseline for FVC between the groups. There was also no difference in the frequency of pulmonary exacerbations between groups, MD -0.18 (95% CI -0.51 to 0.14) (moderate-quality evidence). Similarly, there was no difference between groups in the risk of participants developing novel resistant bacteria, RR 1.00 (95% CI 0.67 to 1.5) (moderate-quality evidence). There were more severe adverse events in the cycled group, but the type of treatment probably makes little or no difference to the results, RR 0.65 (95% CI 0.39 to 1.11) (moderate-quality evidence). There was no difference between groups in the change in weight or height from baseline or in rates of adherence to tobramycin or all trial medicines. The included trial did not assess changes in quality of life, the time to chronic infection with PA or the cost-effectiveness of treatment.

AUTHORS' CONCLUSIONS

Cycled TIS therapy may be beneficial in prolonging the time to recurrence of PA after successful eradication, but further trials are required, specifically addressing this question and in both adults and children.

Thinking outside the box: Association of antimicrobial resistance with climate warming in Europe - A 30 country observational study

The association of antimicrobial resistance (AMR) with climatic factors gained higher attention since resistance increased with increasing local temperatures in the USA. We aimed to investigate whether the explanatory strength of climatic factors holds true in a region encompassing diverse healthcare systems, like Europe. In particular, we determined whether exposure to temporal climate warming is associated with an increase in AMR prevalence for clinically relevant pathogens. A 30-country cross-sectional study was conducted. The six-year prevalence of carbapenem-resistant Pseudomonas aeruginosa (CRPA), Klebsiella pneumoniae (CRKP), Multiresistant Escherichia coli (MREC), and Methicillin-resistant Staphylococcus aureus (MRSA) was determined based on > 900 k clinical isolates. Bi- and multivariate analysis were performed to identify associations with climatic variables using healthcare and socio-economic confounders. CRPA was significantly associated with the warm-season change in temperature, which, alongside corruption perception, explained 78% of total CRPA variance. Accordingly, a 0.5 °C increase of year-wise temperature change (exposition) resulted in a 1.02-fold increase (p = 0.035) in CRPA prevalence (outcome). For a given country, exposition status doubled the odds of outcome attainment compared to non-exposition (OR = 2.03, 95%-CI [1.03-3.99]). Moreover, we found significant associations of CRKP, MREC, and MRSA with the warm-season mean temperature, which had a higher contribution to MRSA variance explanation than outpatient antimicrobial drug use. We identified a novel association between AMR and climatic factors in Europe, which reveals two aspects: climatic factors significantly contribute to the explanation of AMR in different types of healthcare systems, while climate change (i.e. warming) might increase AMR transmission, in particular CRPA.

Viral respiratory tract infections in young children with cystic fibrosis: a prospective full-year seasonal study

Background

Viral respiratory tract infections are common during early childhood. How they impact cystic fibrosis lung disease history in young children is poorly known. The principal aim of our study was to determinate respiratory tract infections frequency in this cystic fibrosis young population. Secondary outcomes were nature of viral agents recovered and impact of such infections.

Methods

We conducted a prospective cohort study of 25 children affected by cystic fibrosis and aged less than 2 years. Nasal samplings were taken systematically monthly or bimonthly with additional samples taken during respiratory tract infections episodes. Ten pathogens were tested by a combination of five duplex RT-PCRs or PCRs: influenza A and B, respiratory syncytial virus (RSV), metapneumovirus (MPV), rhinovirus/enterovirus (RV/EV)), coronavirus (HKU1, NL63, 229E and OC43), parainfluenza virus (1–4), adenovirus and bocavirus (Respiratory Multi-Well System MWS r-gene®, BioMérieux, Marcy l’Étoile, France). Cycle thresholds (CTs) were reported for all positive samples and considered positive for values below 40. Quantitative variables were compared using a nonparametric statistical test (Wilcoxon signed rank for paired comparisons). Pearson’s correlation coefficient (r) was used to assess relationships between two variables. Statistical analyses were performed using SAS v9.4 (SAS Institute, Cary, NC, USA) or GraphPad Prism V6.00 (GraphPad Software, La Jolla, CA, USA). The significance level was set at 0.05.

Results

The mean age at inclusion was 9.6 ± 6.7 months. The patients had 3.4 ± 1.7 respiratory tract infections episodes per child per year. Forty-four respiratory tract infections (69%) were associated with virus: rhinovirus and enterovirus (RV/EV) were implied in 61% of them and respiratory syncytial virus (RSV) in 14%. Only one patient required hospitalization for lower respiratory tract infections. 86% of the patients were treated by antibiotics for a mean of 13.8 ± 6.2 days. RSV infections (n = 6) were usually of mild severity.

Conclusions

Respiratory tract infections in young children with cystic fibrosis were of mild severity, rarely requiring hospitalization. Unsurprisingly, RV/EV were the most frequent agents. RSV-related morbidity seems low in this population. This raises the question of the usefulness of RSV preventive medication in this young population.

The association between pneumococcal vaccination, ethnicity, and the nasopharyngeal microbiota of children in Fiji

BACKGROUND

Streptococcus pneumoniae is a significant global pathogen that colonises the nasopharynx of healthy children. Pneumococcal conjugate vaccines, which reduce nasopharyngeal colonisation of vaccine-type S. pneumoniae, may have broader effects on the nasopharyngeal microbiota; however, data are limited. In Fiji, nasopharyngeal carriage prevalence of S. pneumoniae and other colonising species differ between the two main ethnic groups. Here, we examined the association between the 7-valent pneumococcal conjugate vaccine (PCV7) and the nasopharyngeal microbiota of children in Fiji, including for each of the two main ethnic groups-indigenous Fijians (iTaukei) and Fijians of Indian descent (FID).

METHOD

The nasopharyngeal microbiota of 132 Fijian children was examined using nasopharyngeal swabs collected from 12-month-old iTaukei and FID children who were vaccinated (3 doses PCV7) or unvaccinated in infancy as part of a phase II randomised controlled trial. Microbiota composition was determined by sequencing the V4 region of the 16S rRNA gene. Species-specific carriage of S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus was determined using real-time quantitative PCR. Associations between microbiota composition and other host and environmental factors were considered in the analysis.

RESULTS

PCV7 had no overall impact on microbial diversity or composition. However, ethnic differences were observed in both diversity and composition with iTaukei children having higher relative abundance of Moraxella (p = 0.004) and Haemophilus (p = 0.004) and lower relative abundance of Staphylococcus (p = 0.026), Dolosigranulum (p = 0.004) and Corynebacterium (p = 0.003) compared with FID children. Further, when we stratified by ethnicity, associations with PCV7 could be detected: vaccinated iTaukei children had a lower relative abundance of Streptococcus and Haemophilus compared with unvaccinated iTaukei children (p = 0.022 and p = 0.043, respectively); and vaccinated FID children had a higher relative abundance of Dolosigranulum compared with unvaccinated FID children (p = 0.037). Children with symptoms of an upper respiratory tract infection (URTI) had a significantly different microbiota composition to children without symptoms. The microbiota composition of iTaukei children without URTI symptoms was most similar to the microbiota composition of FID children with URTI symptoms.

CONCLUSIONS

Associations between PCV7 and nasopharyngeal microbiota differed within each ethnic group. This study highlights the influence that ethnicity and URTIs have on nasopharyngeal microbiota.

The role of geographical location and climate on recurrent Pseudomonas infection in young children with Cystic Fibrosis

OBJECTIVES

To determine the association between residence and climate with risk of Pseudomonas aeruginosa (Pa) and other respiratory outcomes.

METHODS

We performed regular bronchoalveolar lavage and upper airway cultures in young children with CF to identify Pa infection. Children were classified for residence as regional or metropolitan. Bronchiectasis was detected on periodic chest computed tomography scans. Multilocus sequence typing determined Pa genotype. Lung function was assessed using Multiple Breath Washout.

RESULTS

Of infants diagnosed with CF between 2006 and 2017, 129 were included in the study. Seven patients moved between metropolitan and regional Victoria and were excluded from analysis. Of the remaining 122 subjects, seventy-four (61%) children resided in metropolitan areas and over half (54%) were male. There were 83 Pa episodes in the 122 children who lived consistently in a geographical location. The incidence rate was 0.15 episodes per person-years. We found weak evidence of a 15% increase in the rate of Pa episodes with increasing average annual maximum temperature (95%CI (0.98, 1.36); p = .086), while the rate of Pa acquision decreased with average annual 3 pm humidity (IRR = 0.96; 95%CI(0.92, 1.0008); p = .054). The rate of Pa episodes was 2.1 times higher in regional participants (95%CI (1.4, 3.1); p = .001) and risk of second episode was more than five times greater (HR 5.7; 95%CI 1.9, 17); p = .002). No difference between regions in lung clearance index and presence of bronchiectasis was detected.

CONCLUSION

Regional residence is associated with risk of acquiring recurrent infection with Pseudomonas aeruginosa in young children with CF.

Seasonal fluctuation of lung function in cystic fibrosis: A national register-based study in two northern European populations

Background

Many risk factors for lung disease in cystic fibrosis (CF) display a seasonal pattern yet it is unclear whether this is reflected in seasonal fluctuations in lung function.

Methods

We conducted a longitudinal study using CF registries in Denmark and the UK. 471 individuals with a median of 104 FEV₁ measurements per person and 7586 individuals with a median of nine FEV₁ measures per person were included from Denmark and the UK respectively. We estimated the effect of seasonality on percent predicted FEV₁ trajectories using mixed effects models whilst adjusting for clinically important covariates.

Results

We found no significant cyclical seasonal variation in lung function in either country. The maximum variation in percent predicted FEV₁ around the yearly average was estimated to be 0.1 percentage points (95%CI 0 to 0.21) and 0.14 percentage points (95%CI 0 to 0.29) in Denmark and the UK, respectively. When considering possible step-like changes between the four seasons, we found that lung function was higher in spring compared to winter in the UK (0.34 percentage points, 95%CI 0.1 to 0.59) though the difference was not of clinical significance.

Conclusion

In both the UK and Denmark there may be small seasonal changes in lung function but this effect is not of clinical importance.

•

It is not well understood how the four seasons affect lung function in CF.

•

We performed a longitudinal analysis in the UK and Danish CF populations.

•

Forty years of data were included in a comprehensive mixed effects models.

•

The seasonal variation was small and not clinically important.

Fatigue in Chronic Respiratory Diseases: Theoretical Framework and Implications For Real-Life Performance and Rehabilitation

Fatigue is a primary disabling symptom in chronic respiratory diseases (CRD) with major clinical implications. However, fatigue is not yet sufficiently explored and is still poorly understood in CRD, making this symptom underdiagnosed and undertreated in these populations. Fatigue is a dynamic phenomenon, particularly in such evolving diseases punctuated by acute events which can, alone or in combination, modulate the degree of fatigue experienced by the patients. This review supports a comprehensive inter-disciplinary approach of CRD-related fatigue and emphasizes the need to consider both its performance and perceived components. Most studies in CRD evaluated perceived fatigue as a trait characteristic using multidimensional scales, providing precious information about its prevalence and clinical impact. However, these scales are not adapted to understand the complex dynamics of fatigue in real-life settings and should be augmented with ecological assessment of fatigue. The state level of fatigue must also be considered during physical tasks as severe fatigue can emerge rapidly during exercise. CRD patients exhibit alterations in both peripheral and central nervous systems and these abnormalities can be exacerbated during exercise. Laboratory tests are necessary to provide mechanistic insights into how and why fatigue develops during exercise in CRD. A better knowledge of the neurophysiological mechanisms underlying perceived and performance fatigability and their influence on real-life performance will enable the development of new individualized countermeasures. This review aims first to shed light on the terminology of fatigue and then critically considers the contemporary models of fatigue and their relevance in the particular context of CRD. This article then briefly reports the prevalence and clinical consequences of fatigue in CRD and discusses the strengths and weaknesses of various fatigue scales. This review also provides several arguments to select the ideal test of performance fatigability in CRD and to translate the mechanistic laboratory findings into the clinical practice and real-world performance. Finally, this article discusses the dose-response relationship to training and the feasibility and validity of using the fatigue produced during exercise training sessions in CRD to optimize exercise training efficiency. Methodological concerns, examples of applications in selected diseases and avenues for future research are also provided.

Nasal microbiota clusters associate with inflammatory response, viral load, and symptom severity in experimental rhinovirus challenge

The role of nasal and fecal microbiota in viral respiratory infections has not been established. We collected nasal swabs and washes, and fecal samples in a clinical study assessing the effect of probiotic Bifidobacterium animalis subsp. lactis Bl-04 on experimental rhinovirus infection. The nasal and fecal microbiota were characterized by 16S rRNA gene sequencing. The resulting data were compared with nasal inflammatory marker concentrations, viral load, and clinical symptoms. By using unsupervised clustering, the nasal microbiota divided into six clusters. The clusters predominant of Staphylococcus, Corynebacterium/Alloiococcus, Moraxella, and Pseudomonadaceae/Mixed had characteristic inflammatory marker and viral load profiles in nasal washes. The nasal microbiota clusters of subjects before the infection associated with the severity of clinical cold symptoms during rhinovirus infection. Rhinovirus infection and probiotic intervention did not significantly alter the composition of nasal or fecal microbiota. Our results suggest that nasal microbiota may influence the virus load, host innate immune response, and clinical symptoms during rhinovirus infection, however, further studies are needed.

Air pollution exposure is associated with MRSA acquisition in young U.S. children with cystic fibrosis

Background

The role of air pollution in increasing susceptibility to respiratory tract infections in the cystic fibrosis (CF) population has not been well described. We recently demonstrated that chronic PM_2.5 exposure is associated with an increased risk of initial Pseudomonas aeruginosa acquisition in young children with CF. The purpose of this study was to determine whether PM_2.5 exposure is a risk factor for acquisition of other respiratory pathogens in young children with CF.

Methods

We conducted a retrospective study of initial acquisition of methicillin susceptible and methicillin resistant Staphylococcus aureus (MSSA and MRSA), Stenotrophomonas maltophilia and Achromobacter xylosoxidans in U.S. children <6 years of age with CF using the CF Foundation Patient Registry, 2003–2009. Multivariable Weibull regression with interval-censored outcomes was used to evaluate the association of PM_2.5 concentration in the year prior to birth and risk of acquisition of each organism.

Results

During follow-up 63%, 17%, 24%, and 5% of children acquired MSSA, MRSA, S. maltophilia, and A. xylosoxidans, respectively. A 10 μg/m³ increase in PM_2.5 exposure was associated with a 68% increased risk of MRSA acquisition (Hazard Ratio: 1.68; 95% Confidence Interval: 1.24, 2.27). PM_2.5 was not associated with acquisition of other respiratory pathogens.

Conclusions

Fine particulate matter is an independent risk factor for initial MRSA acquisition in young children with CF. These results support the increasing evidence that air pollution contributes to pulmonary morbidities in the CF community.

Antibiotic resistance and population structure of cystic fibrosis Pseudomonas aeruginosa isolates from a Spanish multi-centre study

The first Spanish multi-centre study on the microbiology of cystic fibrosis (CF) was conducted from 2013 to 2014. The study involved 24 CF units from 17 hospitals, and recruited 341 patients. The aim of this study was to characterise Pseudomonas aeruginosa isolates, 79 of which were recovered from 75 (22%) patients. The study determined the population structure, antibiotic susceptibility profile and genetic background of the strains. Fifty-five percent of the isolates were multi-drug-resistant, and 16% were extensively-drug-resistant. Defective mutS and mutL genes were observed in mutator isolates (15.2%). Considerable genetic diversity was observed by pulsed-field gel electrophoresis (70 patterns) and multi-locus sequence typing (72 sequence types). International epidemic clones were not detected. Fifty-one new and 14 previously described array tube (AT) genotypes were detected by AT technology. This study found a genetically unrelated and highly diverse CF P. aeruginosa population in Spain, not represented by the epidemic clones widely distributed across Europe, with multiple combinations of virulence factors and high antimicrobial resistance rates (except for colistin).

Seasonality of acquisition of respiratory bacterial pathogens in young children with cystic fibrosis

Background

Seasonal variations are often observed for respiratory tract infections; however, limited information is available regarding seasonal patterns of acquisition of common cystic fibrosis (CF)-related respiratory pathogens. We previously reported differential seasonal acquisition of Pseudomonas aeruginosa in young children with CF and no such variation for methicillin-susceptible Staphylococcus aureus acquisition. The purpose of this study was to describe and compare the seasonal incidence of acquisition of other respiratory bacterial pathogens in young children with CF.

Methods

We conducted a retrospective study to describe and compare the seasonal incidence of methicillin-resistant Staphylococcus aureus (MRSA), Stenotrophomonas maltophilia, Achromobacter xylosoxidans, and Haemophilus influenzae acquisition in young CF patients residing in the U.S. using the Cystic Fibrosis Foundation National Patient Registry, 2003-2009. Log-linear overdispersed Poisson regression was used to evaluate seasonal acquisition of each of these pathogens.

Results

A total of 4552 children met inclusion criteria. During follow-up 910 (20%), 1161 (26%), 228 (5%), and 2148 (47%) children acquired MRSA, S. maltophilia, A. xylosoxidans and H. influenzae, respectively. Compared to winter season, MRSA was less frequently acquired in spring (Incidence Rate Ratio [IRR]: 0.79; 95% Confidence Interval [CI]: 0.65, 0.96) and summer (IRR: 0.69; 95% CI: 0.57, 0.84) seasons. Similarly, a lower rate of A. xylosoxidans acquisition was observed in spring (IRR: 0.59; 95% CI: 0.39, 0.89). For H. influenzae, summer (IRR: 0.88; 95% CI: 0.78, 0.99) and autumn (IRR: 0.78; 95% CI: 0.69, 0.88) seasons were associated with lower acquisition rates compared to winter. No seasonal variation was observed for S. maltophilia acquisition.

Conclusion

Acquisition of CF-related respiratory pathogens displays seasonal variation in young children with CF, with the highest rate of acquisition for most pathogens occurring in the winter. Investigation of factors underlying these observed associations may contribute to our understanding of the aetiology of these infections and guide future infection control strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2511-9) contains supplementary material, which is available to authorized users.

Seasonal changes of lower respiratory tract infections in lung transplant recipients during the first post-transplant year: The Hungarian experience

BACKGROUND

After lung transplantation (LuTX) a high level of immunosuppression is needed to prevent rejection of the graft. Together with earlier colonization by pathogens, immunosuppression makes recipients more susceptible to infections, especially during the first postoperative year. As seasonality of lower respiratory tract infections (LRTI) is well-known in chronic lung diseases, we assessed seasonal changes of pathogen spectrum and number of infections in the first postoperative year in LuTX recipients.

METHODS

LRTI were analyzed in 28 Hungarian adult LuTX patients. Incidence and spectrum of microorganism causing LRTI were evaluated according to post-transplant time and seasonal temperature and humidity changes.

RESULTS

A total of 69 cases of LRTI were registered (average: 1.9 cases/patient; range: 0-14). Gram-negative=59, gram-positive=26, and fungal=31 pathogens were detected, with polymicrobial samples in 46% of all cases. Increased number of LRTI was observed in the cold season (1.68±1.54 vs 0.79±0.92 case/month/patient, P<.01) and significant negative correlations were identified between the incidence of polymicrobial and bacterial infections and temperature (r² =0.1535, P<.05, r² =0.3144, P<.01, respectively). In addition, positive correlation was observed between polymicrobial infections and humidity (r² =0.1403, P<.05). Higher incidence of LRTI was also noted in the cold season, when accounting for the differences in immunosuppression.

CONCLUSION

Seasons influenced the incidence of LRTI in the first postoperative year in LuTX recipients. More intensive vigilance for possible gram-negative and polymicrobial infections is needed in these patients in cold and wet seasons in the continental climate zone, regardless of underlying disease.

An overview of international literature from cystic fibrosis registries. Part 5: Update 2012-2015 on lung disease

Patient registry data is a tool for defining the clinical course and risk factors in patients with less common diseases like Cystic Fibrosis. Forty-one registry-based reports on lung disease in Cystic Fibrosis were published between 2011 and 2015. The aim of this review is to describe and discuss the results of these reports, focusing on the risk factors for lung disease progression, specific microbiologic pathogens (e.g., non-tuberculous mycobacteria), disease complications, comparisons between registries of different countries, the impact of socio-economic status, and evaluation of benefits and costs of therapies. Techniques for improved clinical trial design were also studied. Pediatr Pulmonol. 2016;51:1251-1263. © 2016 Wiley Periodicals, Inc.

Respiratory infection rates differ between geographically distant paediatric cystic fibrosis cohorts

Respiratory infections are a major cause of pulmonary decline in children with cystic fibrosis (CF). We compared the prevalence of infection in early life at geographically distant CF treatment centres participating in the same surveillance programme in Australia.

Lower airway microbiology, inflammation and structural lung disease at annual review were evaluated for 260 children 0–8 years old with CF at 1032 visits to CF treatment centres in Melbourne or Perth.

Melbourne patients were more likely to be culture-positive for common respiratory pathogens at all age groups (odds ratio (OR) 1.85, 95% CI 1.33–2.58). Subjects <2 years old in Melbourne were also more likely to have neutrophil elastase present (OR 3.11, 95% CI 1.62–5.95). Bronchiectasis (OR 2.02, 95% CI 1.21–3.38) and air trapping (OR 2.53, 95% CI 1.42–4.51) in subjects 2–5 years old was more common in Melbourne subjects. The severity of structural lung disease was also worse in Melbourne patients >5 years old. Patients at both centres had a similar rate of hospitalisations and prescribed antibiotics.

No procedural differences were identified that could explain the disparity between pathogen prevalence. Geographical differences in early acquisition of infection may contribute to variability in outcomes between CF centres.

Infection rates different between two Australian paediatric cystic fibrosis patient cohortshttp://ow.ly/PAmG302IYL4

Particulate Respirators Functionalized with Silver Nanoparticles Showed Excellent Real-Time Antimicrobial Effects against Pathogens

Particulate respirators designed to filtrate fine particulate matters usually do not possess antimicrobial functions. The current study aimed to functionalize particulate respirators with silver nanoparticles (nanosilver or AgNPs), which have excellent antimicrobial activities, utilizing a straightforward and effective method. We first enhanced the nanosilver-coating ability of nonwoven fabrics from a particulate respirator through surface modification by sodium oleate. The surfactant treatment significantly improved the fabrics' water wet preference where the static water contact angles reduced from 122° to 56°. Both macroscopic agar-plate tests and microscopic scanning electron microscope (SEM) characterization revealed that nanosilver functionalized fabrics could effectively inhibit the growth of two model bacterial strains (i.e., Staphylococcus aureus and Pseudomonas aeruginosa). The coating of silver nanoparticles would not affect the main function of particulate respirators (i.e., filtration of fine air-borne particles). Nanosilver coated particulate respirators with excellent antimicrobial activities can provide real-time protection to people in regions with severe air pollution against air-borne pathogens.

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.

Country to country variation: what can be learnt from national cystic fibrosis registries

PURPOSE OF REVIEW

This review will address the evolving science involving international comparisons of populations of persons living with cystic fibrosis. Understanding the current clinical outcomes in cystic fibrosis is critical prior to assessing such comparisons. Countries that differ in clinical approaches provide natural experiments to assess those approaches.

RECENT FINDINGS

Recent studies have highlighted that the population of persons with cystic fibrosis is changing; estimates predict a continued growth of cystic fibrosis populations with substantial increases in persons with cystic fibrosis who are adults. Additional work highlighted differences in subpopulations (i.e. children); US cystic fibrosis children appear to have better lung function, but similar nutritional status, compared to UK cystic fibrosis children. These differences were associated with differences in intensity of care, with a higher proportion of US children receiving more cystic fibrosis-specific therapies. Additional research raises important questions regarding potential sampling bias in different patient registries and differing rates of unconfirmed cases of cystic fibrosis. These and other limitations are highlighted.

SUMMARY

Differences in both demographics and clinical outcomes in cystic fibrosis between nations can be informative, but, like many types of observational research, are at risk of unrecognized bias. Despite this limitation, these comparisons can lead to substantive improvements in care in cystic fibrosis.

Fine particulate matter exposure and initial Pseudomonas aeruginosa acquisition in cystic fibrosis

RATIONALE

Increasing evidence suggests that exposure to ambient air pollution contributes to the severity of cystic fibrosis (CF) respiratory disease in school-age children and adults; however, the effects of air pollution on young children with CF are poorly understood.

OBJECTIVES

To investigate the association of exposure to fine particulate matter less than 2.5 μm in aerodynamic diameter (PM2.5) and initial Pseudomonas aeruginosa acquisition in young children with CF.

METHODS

Retrospective analysis of initial Pseudomonas acquisition in children 6 years of age or younger, using Cystic Fibrosis Foundation National Patient Registry data from 2003 to 2009. PM2.5 exposure was estimated by inverse distance weighting methods based on air pollution monitors within 30 miles of place of residence, for the year before the patient's birth. Multivariable Weibull regression with interval-censored outcomes was done to evaluate the association of time to initial Pseudomonas acquisition and PM2.5 concentrations.

MEASUREMENTS AND MAIN RESULTS

A total of 3,575 children met inclusion criteria and 48% (n=1,711) acquired Pseudomonas at a median age of 15 months (25th-75th percentiles, 9-25 mo). An increase in PM2.5 exposure of 10 μg/m3 was associated with a 24% increased risk of Pseudomonas acquisition (95% confidence interval, 1-51%) during follow-up. Results were generally consistent across exposure metrics.

CONCLUSIONS

These results suggest that increased PM2.5 exposure is associated with earlier Pseudomonas acquisition in young children with CF and may play an important, previously unrecognized, role in the etiology of initial Pseudomonas infection.

Association of meteorological and geographical factors and risk of initial Pseudomonas aeruginosa acquisition in young children with cystic fibrosis

Initial infection with the sentinel respiratory pathogen in children with cystic fibrosis (CF), Pseudomonas aeruginosa (Pa), is generally with environmental strains of this ubiquitous organism. The purpose of this study was to evaluate the associations between meteorological and geographical factors and risk of initial Pa acquisition in young children with CF. Using the U.S. Cystic Fibrosis Foundation Patient Registry from 2003 to 2009, 3463 patients met inclusion criteria, of which 48% (n = 1659) acquired Pa during follow-up. From multivariable Weibull regression, increased risk of Pa acquisition was associated with increasing temperature [hazard ratio (HR) per 1 °C: 1·13; 95% confidence interval (CI) 1·08-1·13], dew point (HR per 1 °C: 1·10, 95% CI 1·07-1·13), rainfall (HR per cm: 1·10, 95% CI 1·07-1·12), latitude (HR per 1 °C northing: 1·15, 95% CI 1·11-1·20), longitude (HR per 1 °C easting: 1·01, 95% CI 1·01-1·02) and elevation (HR per 100 m: 1·05, 95% CI 1·03-1·07). These results suggest that environmental factors may play a previously unrecognized role in the aetiology of initial Pa acquisition.

Geographic variations in cystic fibrosis: An analysis of the U.S. CF Foundation Registry

BACKGROUND

Emerging evidence suggests that the prevalence of pathogens common in cystic fibrosis (CF) may be unevenly distributed across the United States (U.S.). However, very little is known regarding the U.S. distribution of other CF modifiers such as medication usage and patient demographics. Therefore, we sought to determine if regional differences exist in the distribution of demographic variables and patient disease characteristics in the U.S. that may play a role in differential CF outcomes.

METHODS

Data were analyzed from the 30,896 subjects in the U.S. CF Foundation Patient Registry during the years 2007-2012, via geographical grouping of states based upon the Nationwide Inpatient Sample classification.

RESULTS

Significant differences in racial distribution were seen, including half of the total U.S. African-American CF population residing in the South. Both African-Americans and Hispanics had increased Medicaid usage (52.2%, 41.8%, respectively). Culture-reported pathogens were markedly different across the U.S., with the highest percentage of patients with Methicillin-resistant Staphylococcus aureus (41.9%), Pseudomonas aeruginosa (71.2%), and non-tuberculous mycobacterium (10.0%) in the South. The South region also had the lowest mean body mass index and forced expiratory volume in one second. Chronic medication usage such as inhaled tobramycin or macrolides followed P. aeruginosa distribution, while inhaled dornase alfa was most used in the West (84.7%). Co-morbid conditions varied, with the highest percentage of depressed subjects in the Midwest (18.3%). Mean regional mortality rates were not statistically different among regions, although highest in each age grouping of the South.

CONCLUSIONS

The U.S. has significant regional variations in CF demographics, insurance, pathogens, medication usage, and co-morbidities, without an overall impact on regional mortality. Regional variations in care practices should be studied further based on the findings.

Children and young adults with CF in the USA have better lung function compared with the UK

BACKGROUND

People with cystic fibrosis (CF) are managed differently in the USA and UK providing an opportunity to learn from differences in practice patterns.

OBJECTIVES

To compare cross-sectional demographics, practice patterns and clinical outcomes between US and UK CF patients.

METHODS

This was a cross-sectional study using 2010 data from patients in the US Cystic Fibrosis Foundation and the UK Cystic Fibrosis patient registries. The a priori outcome measures of interest were lung function and nutritional status. Descriptive statistics and two sample comparisons were performed. Stratification and multivariable linear regression were used to adjust for confounding.

RESULTS

The study cohort included 13 777 children and 11 058 adults from the USA and 3968 children and 3965 adults from the UK. In children, mean body mass index centiles were similar. Lung function (FEV1 and FVC% predicted) was significantly higher in US patients ages 6-25 years of age. In a regression model adjusted for only age, FEV1% predicted was on average 3.31% of predicted (95% CI 2.65 to 3.96) higher in the USA compared with the UK. When adjusted for age, age at diagnosis, gender, pancreatic insufficiency and genotype, FEV1% predicted was on average 3.03% of predicted (95% CI 2.37 to 3.69) higher in the USA compared with the UK These differences persisted despite adjustment for possible confounders. Hypertonic saline and dornase alfa were much more commonly prescribed in US children.

CONCLUSIONS

Children and young adults with CF have better lung function in the USA compared with the UK despite similar nutritional status.

Differential geographical risk of initial Pseudomonas aeruginosa acquisition in young US children with cystic fibrosis

Pseudomonas aeruginosa is the sentinel respiratory pathogen in cystic fibrosis patients. We conducted a retrospective study to examine whether state of residence affected risk of P. aeruginosa acquisition among US children under 6 years of age with cystic fibrosis by using data from the Cystic Fibrosis Foundation National Patient Registry, 2003-2009. The outcome was time to first isolation of P. aeruginosa from a respiratory culture. We used a Bayesian hierarchical Weibull regression model with interval-censored outcomes. Spatial random effects, included at the state level and modeled using an intrinsic conditional autoregressive prior, allowed estimation of the residual spatial correlation. The regression portion of the model was adjusted for demographic and disease characteristics potentially affecting P. aeruginosa acquisition. A total of 3,608 children met the inclusion criteria and were followed for an average of 2.1 (standard deviation, 1.6) years. P. aeruginosa was cultured in 1,714 (48%) subjects. There was a moderately elevated spatial residual relative risk. An estimated 95% credible interval for the residual hazard ratio under 1 of the fitted models was 0.64-1.57; the strongest positive association was observed in the Southern states. The fact that risk for P. aeruginosa acquisition displayed spatial dependence suggests that regional factors, such as climate, may play an important role in P. aeruginosa acquisition.

The microbiome in pediatric cystic fibrosis patients: the role of shared environment suggests a window of intervention

BACKGROUND

Cystic fibrosis (CF) is caused by mutations in the CFTR gene that predispose the airway to infection. Chronic infection by pathogens such as Pseudomonas aeruginosa leads to inflammation that gradually degrades lung function, resulting in morbidity and early mortality. In a previous study of CF monozygotic twins, we demonstrate that genetic modifiers significantly affect the establishment of persistent P. aeruginosa colonization in CF. Recognizing that bacteria other than P. aeruginosa contribute to the CF microbiome and associated pathology, we used deep sequencing of sputum from pediatric monozygotic twins and nontwin siblings with CF to characterize pediatric bacterial communities and the role that genetics plays in their evolution.

FINDINGS

We found that the microbial communities in sputum from pediatric patients living together were much more alike than those from pediatric individuals living apart, regardless of whether samples were taken from monozygous twins or from nontwin CF siblings living together, which we used as a proxy for dizygous twins. In contrast, adult communities were comparatively monolithic and much less diverse than the microbiome of pediatric patients.

CONCLUSION

Taken together, these data and other recent studies suggest that as patients age, the CF microbiome becomes less diverse, more refractory to treatment and dominated by mucoid P. aeruginosa, as well as being associated with accelerated pulmonary decline. Our studies show that the microbiome of pediatric patients is susceptible to environmental influences, suggesting that interventions to preserve the community structure found in young CF patients might be possible, perhaps slowing disease progression.