Association of short-term PM2.5 exposure with airway innate immune response, microbiota and metabolism alterations in human airways

Exposure to fine particulate matter (PM2.5) has been associated with impaired airway innate immunity, leading to diverse lung disorders. However, the mechanisms of the adverse effects of PM2.5 on the airway innate immune system has not been adequately elucidated. This study aimed to investigate the association between short-term exposure to ambient PM2.5 and airway innate immune responses. A panel study of 53 undergraduate students was conducted in November 2020 and April 2021. Levels of airway innate immune biomarkers including interleukin-1β (IL-1β), IL-4, IL-6, IL-8, IL-17, interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO), and matrix metalloproteinase-9 (MMP-9) in induced sputum were measured, and airway microbiota and metabolites examined. Linear mixed-effect model was used to evaluate the effects of short-term exposure to PM2.5 on the above-listed airway immune biomarkers. The results indicated that for every 10 μg/m3 increase in PM2.5 concentration (at lag3), was associated with an increase of 21.3 % (5.4 %-37.1 %), 26.2 % (0.30 %-52.1 %), 22.4 % (0.70 %-44.2 %), 27.4 % (6.6 %-48.3 %), 18.3 % (4.6 %-31.9 %), 3.9 % (0.20 %-7.6 %) or 2.4 % (0.10 %-4.7 %) in IL-6, TNF-α, IL-17, IL-4, IFN-γ, MPO, or MMP-9 levels, respectively. Meanwhile, exposure to higher levels of ambient PM2.5 was found to significantly modulate airway microbiota and metabolite profile. Specifically, Prevotella and Fusobacterium, as well as 96 different metabolites were associated with PM2.5 levels. The metabolic pathways associated with these metabolites mainly included amino acid biosynthesis and metabolism. Notably, PM2.5 exposure-induced alterations of some airway microbiota were significantly correlated with specific airway metabolic change. Taken together, these results demonstrated that short-term exposure to PM2.5 was associated with alterations of airway immune response, microbial dysbiosis and changes of metabolites. This study provided insights into the mechanisms underlying PM2.5-induced airway innate immune responses.

Association of Pseudomonas aeruginosa incident infections with adherence to cystic fibrosis foundation care guidelines

BACKGROUND

Care guidelines for cystic fibrosis (CF) have been developed to enhance consistent care and to improve health outcomes. We determined if adherence to CF care guidelines predicted P. aeruginosa incidence rates (Pa-IR) at U.S. CF centers in 2018.

METHODS

This cross-sectional CF Foundation Patient Registry study included 82 adult and 132 pediatric centers. Adherence to 12 guidelines was defined categorically (guideline met) or as a continuous measure (proportion of patients being treated/evaluated per guideline). Association of adherence to individual guidelines with Pa-IR, accounted for center and patient characteristics relevant to Pa-IR and were modeled using random forests and weighted-least-squares (WLS) analyses.

RESULTS

The mean Pa-IR was 0.2 cases/patient-years at risk (SE 0.0074) for all centers combined. Guideline adherence was lowest for ≥4 bacterial cultures/year (54% of centers) and annual oral glucose tolerance test (OGTT) (48% of centers), and highest for annual non-tuberculous mycobacteria (NTM) sputum culture (98%). The mean number of guidelines met was 6.7 and higher for pediatric (7.3) than adult (5.6) centers, (p<0.001). The number of guidelines met correlated negatively with Pa-IR (β=-0.007, p = 0.043). Macrolide prescription and annual OGTT per guideline were associated with lower and higher Pa-IR, respectively. Centers with lower center-wide lung function, higher proportion of pwCF with low body-mass index, and location in the Southwest had higher Pa-IR.

CONCLUSION

Overall adherence to guidelines was high except for performing ≥4 bacterial cultures/year and OGTT. Higher Pa-IR was associated with center characteristics and lower guideline adherence. The lower Pa-IR with greater adherence to guidelines suggests that focusing on quality care can positively impact Pa-IR.

The Effectiveness of Ultraviolet-C (UV-C) Irradiation on the Viability of Airborne Pseudomonas aeruginosa

Pseudomonas aeruginosa (Pa) is the predominant bacterial pathogen in people with cystic fibrosis (CF) and can be transmitted by airborne droplet nuclei. Little is known about the ability of ultraviolet band C (UV-C) irradiation to inactivate Pa at doses and conditions relevant to implementation in indoor clinical settings. We assessed the effectiveness of UV-C (265 nm) at up to seven doses on the decay of nebulized Pa aerosols (clonal Pa strain) under a range of experimental conditions. Experiments were done in a 400 L rotating sampling drum. A six-stage Andersen cascade impactor was used to collect aerosols inside the drum and the particle size distribution was characterized by an optical particle counter. UV-C effectiveness was characterized relative to control tests (no UV-C) of the natural decay of Pa. We performed 112 tests in total across all experimental conditions. The addition of UV-C significantly increased the inactivation of Pa compared with natural decay alone at all but one of the UV-C doses assessed. UV-C doses from 246-1968 µW s/cm² had an estimated effectiveness of approximately 50-90% for airborne Pa. The effectiveness of doses ≥984 µW s/cm² were not significantly different from each other (p-values: 0.365 to ~1), consistent with a flattening of effectiveness at higher doses. Modelling showed that delivering the highest dose associated with significant improvement in effectiveness (984 µW s/cm²) to the upper air of three clinical rooms would lead to lower room doses from 37-49% of the 8 h occupational limit. Our results suggest that UV-C can expedite the inactivation of nebulized airborne Pa under controlled conditions, at levels that can be delivered safely in occupied settings. These findings need corroboration, but UV-C may have potential applications in locations where people with CF congregate, coupled with other indoor and administrative infection control measures.

Aqueous lithium chloride solution as a non-toxic bactericidal and fungicidal disinfectant for air-conditioning systems: Efficacy and mechanism

Airborne pathogenic bacteria and fungi transmitted through air-conditioning (AC) systems have been identified as a major public health risk. Air scrubbing is a promising liquid-based air disinfection technique that captures and inactivates airborne pathogens in liquid disinfectants. However, owing to the drawbacks of irritating odor and toxicity, the commonly-used chemical disinfectants cannot be employed for AC systems. This study aimed to unveil the inactivation performance and mechanism of non-toxic and chemically stable aqueous lithium chloride (LiCl) solution-the popular liquid desiccant in the AC systems-as a user-friendly disinfectant. Four prominent airborne pathogenic bacteria and fungi were exposed to the LiCl solution under various conditions. The inactivation effects were quantified with fluorescence-staining-based confocal microscopy and verified with the pathogens' membrane integrity variations, intracellular substance leakage, and morphological changes. Results showed that LiCl solution was remarkably efficient in inactivating the pathogens within 60 min, with an efficacy of 35.2-96.2%. The solution's inactivation ability was promoted by increasing the temperatures and concentrations; however, it appeared insensitive to exposure time over 30 min. We then explored the inactivation mechanism of LiCl solution by assessing cellular protein leakages and compared the inactivation rates with those of NaCl solution. The extracellular protein increased by over 470% after being exposed to LiCl solution. The inactivation rate was also considerably higher than in NaCl solution under the same osmotic pressure (24.79 MPa). We suggest that apart from osmotic pressure, the inactivation is reinforced by Li⁺-specific properties, including its strong water attraction that deprived the solvation shells of microbial protein and caused protein denaturation. We propose that aqueous LiCl solution may act as a user-friendly disinfectant for air-scrubbing due to its attractive characteristics, including its non-toxicity, odorless nature, and chemical stability. These findings may open up a "green" way to disinfect airborne pathogens and safeguard public health.

Role of angiotensin-converting enzyme 2 in fine particulate matter-induced acute lung injury

Fine particulate matter (PM2.5) pollution poses significant health concerns worldwide and can cause respiratory diseases. However, how it causes health problems is still poorly understood. Angiotensin-converting enzyme (ACE)2 is a terminal carboxypeptidase implicated in the functions of renin-angiotensin system (RAS) and plays a crucial role in the control of lung inflammation. To investigate whether ACE2 functions in PM2.5-induced lung inflammation, wild-type (WT) C57BL/6J mice and ACE2 knock-out (KO) mice were intratracheally instilled with PBS or PM2.5 suspension for 3 consecutive days, respectively. The concentrations of cytokines in bronchoalveolar lavage fluid (BALF) were determined by ELISA. The expression of ACE2 and ACE and activation of inflammatory signaling pathways in lung tissues were evaluated by immunofluorescence staining and Western blotting. We found that PM2.5 exposure increased ACE2 expression. Loss of ACE2 significantly elevated the levels of total proteins, total cells, and the concentrations of MCP-1, IL-1β in BALF after PM2.5 challenge. Additionally, loss of ACE2 enhanced lung pathologies, airway resistance, and inflammatory signaling activation. Collectively, loss of ACE2 exacerbates PM2.5-induced acute lung injury in mice.

Evaluation of four sampling devices for Burkholderia pseudomallei laboratory aerosol studies

Previous field and laboratory studies investigating airborne Burkholderia pseudomallei have used a variety of different aerosol samplers to detect and quantify concentrations of the bacteria in aerosols. However, the performance of aerosol samplers can vary in their ability to preserve the viability of collected microorganisms, depending on the resistance of the organisms to impaction, desiccation, or other stresses associated with the sampling process. Consequently, sampler selection is critical to maximizing the probability of detecting viable microorganisms in collected air samples in field studies and for accurate determination of aerosol concentrations in laboratory studies. To inform such decisions, the present study assessed the performance of four laboratory aerosol samplers, specifically the all-glass impinger (AGI), gelatin filter, midget impinger, and Mercer cascade impactor, for collecting aerosols containing B. pseudomallei generated from suspensions in two types of culture media. The results suggest that the relative performance of the sampling devices is dependent on the suspension medium utilized for aerosolization. Performance across the four samplers was similar for aerosols generated from suspensions supplemented with 4% glycerol. However, for aerosols generated from suspensions without glycerol, use of the filter sampler or an impactor resulted in significantly lower estimates of the viable aerosol concentration than those obtained with either the AGI or midget impinger. These results demonstrate that sampler selection has the potential to affect estimation of doses in inhalational animal models of melioidosis, as well as the likelihood of detection of viable B. pseudomallei in the environment, and will be useful to inform design of future laboratory and field studies.

Environmental Microbial Contamination during Cystic Fibrosis Group-Based Psychotherapy

Living with cystic fibrosis (CF) exposes patients to the risk of developing anxiety and depression, with therapeutic compliance reduction, hospitalization increase, and quality of life and health outcomes deterioration. As pulmonary infections represent the major cause of morbidity and mortality in patients with CF, environmental contamination due to droplet dispersion and the potential transmission from environment to such patients should be prevented. Therefore, in-person contact, including group-based psychotherapy, are strongly discouraged. Nevertheless, group sharing of disease-related experiences represents a way to recover the inner resources essential for dealing with a chronic pathology. Keeping in mind the guidelines for infection control, the aim of this study is to evaluate the risk of the dissemination of microorganisms in a restricted environment where patients with CF attend group psychotherapy sessions. Five patients, selected according to their microbiological status, attended 32 group-based psychological/psychoanalytic meetings. Before each session, they were asked to observe the infection control recommendations. Microbiological environmental monitoring (MEM) has been performed to evaluate both air and surface contamination. As reported, a strict observation of standard precautions allows one to avoid environmental contamination by pathogens of the CF respiratory tract. Although infection control guidelines discourage group-based psychological/psychoanalytic interventions, our observations report the feasibility and safety of group psychotherapy when strict precautions are taken.

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.

Multidrug-resistant Gram-negative bacterial infections in solid organ transplant recipients-Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of infections due to multidrug-resistant (MDR) Gram-negative bacilli in the pre- and post-transplant period. MDR Gram-negative bacilli, including carbapenem-resistant Enterobacteriaceae, MDR Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii, remain a threat to successful organ transplantation. Clinicians now have access to at least five novel agents with activity against some of these organisms, with others in the advanced stages of clinical development. No agent, however, provides universal and predictable activity against any of these pathogens, and very little is available to treat infections with MDR nonfermenting Gram-negative bacilli including A baumannii. Despite advances, empiric antibiotics should be tailored to local microbiology and targeted regimens should be tailored to susceptibilities. Source control remains an important part of the therapeutic armamentarium. Morbidity and mortality associated with infections due to MDR Gram-negative organisms remain unacceptably high. Heightened infection control and antimicrobial stewardship initiatives are needed to prevent these infections, curtail their transmission, and limit the evolution of MDR Gram-negative pathogens, especially in the setting of organ transplantation.

High-Level PM2.5/PM10 Exposure Is Associated With Alterations in the Human Pharyngeal Microbiota Composition

Previous studies showed that high concentration of particulate matter (PM) 2.5 and PM10 carried a large number of bacterial and archaeal species, including pathogens and opportunistic pathogens. In this study, pharyngeal swabs from 83 subjects working in an open air farmer’s market were sampled before and after exposure to smog with PM2.5 and PM10 levels up to 200 and 300 μg/m³, respectively. Their microbiota were investigated using high-throughput sequencing targeting the V3–V4 regions of the 16S rRNA gene. The genus level phylotypes was increased from 649 to 767 in the post-smog pharyngeal microbiota, of which 142 were new and detected only in the post-smog microbiota. The 142 new genera were traced to sources such as soil, marine, feces, sewage sludge, freshwater, hot springs, and saline lakes. The abundance of the genera Streptococcus, Haemophilus, Moraxella, and Staphylococcus increased in the post-smog pharyngeal microbiota. All six alpha diversity indices and principal component analysis showed that the taxonomic composition of the post-smog pharyngeal microbiota was significantly different to that of the pre-smog pharyngeal microbiota. Redundancy analysis showed that the influences of PM2.5/PM10 exposure and smoking on the taxonomic composition of the pharyngeal microbiota were statistically significant (p < 0.001). Two days of exposure to high concentrations of PM2.5/PM10 changed the pharyngeal microbiota profiles, which may lead to an increase in respiratory diseases. Wearing masks could reduce the effect of high-level PM2.5/PM10 exposure on the pharyngeal microbiota.

Epidemiology, Biology, and Impact of Clonal Pseudomonas aeruginosa Infections in Cystic Fibrosis

Chronic lower airway infection with Pseudomonas aeruginosa is a major contributor to morbidity and mortality in individuals suffering from the genetic disease cystic fibrosis (CF). Whereas it was long presumed that each patient independently acquired unique strains of P. aeruginosa present in their living environment, multiple studies have since demonstrated that shared strains of P. aeruginosa exist among individuals with CF. Many of these shared strains, often referred to as clonal or epidemic strains, can be transmitted from one CF individual to another, potentially reaching epidemic status. Numerous epidemic P. aeruginosa strains have been described from different parts of the world and are often associated with an antibiotic-resistant phenotype. Importantly, infection with these strains often portends a worse prognosis than for infection with nonclonal strains, including an increased pulmonary exacerbation rate, exaggerated lung function decline, and progression to end-stage lung disease. This review describes the global epidemiology of clonal P. aeruginosa strains in CF and summarizes the current literature regarding the underlying biology and clinical impact of globally important CF clones. Mechanisms associated with patient-to-patient transmission are discussed, and best-evidence practices to prevent infections are highlighted. Preventing new infections with epidemic P. aeruginosa strains is of paramount importance in mitigating CF disease progression.

Infection Prevention and Control in Pediatric Ambulatory Settings

Since the American Academy of Pediatrics published its statement titled "Infection Prevention and Control in Pediatric Ambulatory Settings" in 2007, there have been significant changes that prompted this updated statement. Infection prevention and control is an integral part of pediatric practice in ambulatory medical settings as well as in hospitals. Infection prevention and control practices should begin at the time the ambulatory visit is scheduled. All health care personnel should be educated regarding the routes of transmission and techniques used to prevent the transmission of infectious agents. Policies for infection prevention and control should be written, readily available, updated every 2 years, and enforced. Many of the recommendations for infection control and prevention from the Centers for Disease Control and Prevention for hospitalized patients are also applicable in the ambulatory setting. These recommendations include requirements for pediatricians to take precautions to identify and protect employees likely to be exposed to blood or other potentially infectious materials while on the job. In addition to emphasizing the key principles of infection prevention and control in this policy, we update those that are relevant to the ambulatory care patient. These guidelines emphasize the role of hand hygiene and the implementation of diagnosis- and syndrome-specific isolation precautions, with the exemption of the use of gloves for routine diaper changes and wiping a well child's nose or tears for most patient encounters. Additional topics include respiratory hygiene and cough etiquette strategies for patients with a respiratory tract infection, including those relevant for special populations like patients with cystic fibrosis or those in short-term residential facilities; separation of infected, contagious children from uninfected children when feasible; safe handling and disposal of needles and other sharp medical devices; appropriate use of personal protective equipment, such as gloves, gowns, masks, and eye protection; and appropriate use of sterilization, disinfection, and antisepsis. Lastly, in this policy, we emphasize the importance of public health interventions, including vaccination for patients and health care personnel, and outline the responsibilities of the health care provider related to prompt public health notification for specific reportable diseases and communication with colleagues who may be providing subsequent care of an infected patient to optimize the use of isolation precautions and limit the spread of contagions.

Management of multidrug resistant Gram-negative bacilli infections in solid organ transplant recipients: SET/GESITRA-SEIMC/REIPI recommendations

Solid organ transplant (SOT) recipients are especially at risk of developing infections by multidrug resistant (MDR) Gram-negative bacilli (GNB), as they are frequently exposed to antibiotics and the healthcare setting, and are regulary subject to invasive procedures. Nevertheless, no recommendations concerning prevention and treatment are available. A panel of experts revised the available evidence; this document summarizes their recommendations: (1) it is important to characterize the isolate's phenotypic and genotypic resistance profile; (2) overall, donor colonization should not constitute a contraindication to transplantation, although active infected kidney and lung grafts should be avoided; (3) recipient colonization is associated with an increased risk of infection, but is not a contraindication to transplantation; (4) different surgical prophylaxis regimens are not recommended for patients colonized with carbapenem-resistant GNB; (5) timely detection of carriers, contact isolation precautions, hand hygiene compliance and antibiotic control policies are important preventive measures; (6) there is not sufficient data to recommend intestinal decolonization; (7) colonized lung transplant recipients could benefit from prophylactic inhaled antibiotics, specially for Pseudomonas aeruginosa; (8) colonized SOT recipients should receive an empirical treatment which includes active antibiotics, and directed therapy should be adjusted according to susceptibility study results and the severity of the infection.

Divergent taxonomic and functional responses of microbial communities to field simulation of aeolian soil erosion and deposition

Aeolian soil erosion and deposition have worldwide impacts on agriculture, air quality and public health. However, ecosystem responses to soil erosion and deposition remain largely unclear in regard to microorganisms, which are the crucial drivers of biogeochemical cycles. Using integrated metagenomics technologies, we analysed microbial communities subjected to simulated soil erosion and deposition in a semiarid grassland of Inner Mongolia, China. As expected, soil total organic carbon and plant coverage were decreased by soil erosion, and soil dissolved organic carbon (DOC) was increased by soil deposition, demonstrating that field simulation was reliable. Soil microbial communities were altered (p < .039) by both soil erosion and deposition, with dramatic increase in Cyanobacteria related to increased stability in soil aggregates. amyA genes encoding α-amylases were specifically increased (p = .01) by soil deposition and positively correlated (p = .02) to DOC, which likely explained changes in DOC. Surprisingly, most of microbial functional genes associated with carbon, nitrogen, phosphorus and potassium cycling were decreased or unaltered by both erosion and deposition, probably arising from acceleration of organic matter mineralization. These divergent responses support the necessity to include microbial components in evaluating ecological consequences. Furthermore, Mantel tests showed strong, significant correlations between soil nutrients and functional structure but not taxonomic structure, demonstrating close relevance of microbial function traits to nutrient cycling.

Long-term clinical outcomes of 'Prairie Epidemic Strain' Pseudomonas aeruginosa infection in adults with cystic fibrosis

RATIONALE

Epidemic Pseudomonas aeruginosa (PA) plays an important role in cystic fibrosis (CF) lung disease. A novel strain, the 'Prairie Epidemic Strain' (PES), has been identified in up to 30% of patients in Prairie-based Canadian CF centres.

OBJECTIVE

To determine the incidence, prevalence and long-term clinical impact of PES infection.

METHODS

A cohort of adults with CF was followed from 1980 to 2014 where bacteria isolated from clinical encounters were prospectively collected. Strain typing was performed using pulse-field gel electrophoresis and multilocus sequence typing. Patients were divided into one of four cohorts: no PA, transient PA, chronic PA with unique strains and chronic PES. Proportional Cox hazard and linear mixed models were used to assess for CF-associated respiratory death or transplantation, and rates of %FEV₁ and body mass index (BMI) decline.

RESULTS

274 patients (51.7% male) were analysed: 44--no PA, 29--transient PA, 137--unique PA, 64--PES. A total of 92 patients (33.6%) died or underwent lung transplantation (2423.0 patient-years). PES infection was associated with greater risk of respiratory death or lung transplant compared with the no PA group (aHR, 3.94 (95% CI 1.18 to 13.1); p=0.03) and unique PA group (aHR, 1.75 (95% CI 1.05 to 2.92) p=0.03). Rate of lung function decline (%FEV₁ predicted) was greatest in the PES group (1.73%/year (95% CI 1.63% to 1.82%); p<0.001). BMI improved over time but at an attenuated rate in the PES group (p=0.001).

CONCLUSIONS

Infection with PES was associated with increased patient morbidity through three decades and manifested in an increased risk of respiratory death and/or lung transplantation.

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 Prevention and Control Guideline for Cystic Fibrosis: 2013 Update

The 2013 Infection Prevention and Control (IP&C) Guideline for Cystic Fibrosis (CF) was commissioned by the CF Foundation as an update of the 2003 Infection Control Guideline for CF. During the past decade, new knowledge and new challenges provided the following rationale to develop updated IP&C strategies for this unique population:

1.The need to integrate relevant recommendations from evidence-based guidelines published since 2003 into IP&C practices for CF. These included guidelines from the Centers for Disease Control and Prevention (CDC)/Healthcare Infection Control Practices Advisory Committee (HICPAC), the World Health Organization (WHO), and key professional societies, including the Infectious Diseases Society of America (IDSA) and the Society for Healthcare Epidemiology of America (SHEA). During the past decade, new evidence has led to a renewed emphasis on source containment of potential pathogens and the role played by the contaminated healthcare environment in the transmission of infectious agents. Furthermore, an increased understanding of the importance of the application of implementation science, monitoring adherence, and feedback principles has been shown to increase the effectiveness of IP&C guideline recommendations.

2.Experience with emerging pathogens in the non-CF population has expanded our understanding of droplet transmission of respiratory pathogens and can inform IP&C strategies for CF. These pathogens include severe acute respiratory syndrome coronavirus and the 2009 influenza A H1N1. Lessons learned about preventing transmission of methicillin-resistantStaphylococcus aureus(MRSA) and multidrug-resistant gram-negative pathogens in non-CF patient populations also can inform IP&C strategies for CF.

Assessment of the Microbial Constituents of the Home Environment of Individuals with Cystic Fibrosis (CF) and Their Association with Lower Airways Infections

INTRODUCTION

Cystic fibrosis (CF) airways are colonized by a polymicrobial community of organisms, termed the CF microbiota. We sought to define the microbial constituents of the home environment of individuals with CF and determine if it may serve as a latent reservoir for infection.

METHODS

Six patients with newly identified CF pathogens were included. An investigator collected repeat sputum and multiple environmental samples from their homes. Bacteria were cultured under both aerobic and anaerobic conditions. Morphologically distinct colonies were selected, purified and identified to the genus and species level through 16S rRNA gene sequencing. When concordant organisms were identified in sputum and environment, pulsed-field gel electrophoresis (PFGE) was performed to determine relatedness. Culture-independent bacterial profiling of each sample was carried out by Illumina sequencing of the V3 region of the 16s RNA gene.

RESULTS

New respiratory pathogens prompting investigation included: Mycobacterium abscessus(2), Stenotrophomonas maltophilia(3), Pseudomonas aeruginosa(3), Pseudomonas fluorescens(1), Nocardia spp.(1), and Achromobacter xylosoxidans(1). A median 25 organisms/patient were cultured from sputum. A median 125 organisms/home were cultured from environmental sites. Several organisms commonly found in the CF lung microbiome were identified within the home environments of these patients. Concordant species included members of the following genera: Brevibacterium(1), Microbacterium(1), Staphylococcus(3), Stenotrophomonas(2), Streptococcus(2), Sphingomonas(1), and Pseudomonas(4). PFGE confirmed related strains (one episode each of Sphinogomonas and P. aeruginosa) from the environment and airways were identified in two patients. Culture-independent assessment confirmed that many organisms were not identified using culture-dependent techniques.

CONCLUSIONS

Members of the CF microbiota can be found as constituents of the home environment in individuals with CF. While the majority of isolates from the home environment were not genetically related to those isolated from the lower airways of individuals with CF suggesting alternate sources of infection were more common, a few genetically related isolates were indeed identified. As such, the home environment may rarely serve as either the source of infection or a persistent reservoir for re-infection after clearance.

Development and Validation of a PCR Assay To Detect the Prairie Epidemic Strain of Pseudomonas aeruginosa from Patients with Cystic Fibrosis

The monitoring of epidemic Pseudomonas aeruginosa is important for cystic fibrosis (CF) infection control. The prairie epidemic strain (PES) is common in western Canadian CF clinics. Using whole-genome sequencing, we identified a novel genomic island and developed a PCR assay for PES. Against a collection of 186 P. aeruginosa isolates, the assay had 98% sensitivity and 100% specificity.

Infection control knowledge, beliefs and behaviours amongst cystic fibrosis patients with epidemic Pseudomonas aeruginosa

Background

Epidemic P. aeruginosa (ePA) infections are common in cystic fibrosis (CF) and have been associated with accelerated clinical decline. Factors associated with ePA are unclear, and evidence based infection control interventions are lacking.

Methods

We prospectively collect all bacterial pathogens from adult CF patients. We performed PA strain typing on retrospectively collected enrolment samples and recent isolates to identify patients infected with ePA. All patients attending our clinic were approached to complete a survey on infection control knowledge, beliefs and exposures. We analyzed responses of those with ePA relative to the entire cohort without ePA as well as those infected with unique strains of P. aeruginosa to assess for risk factors for ePA and differences in infection control knowledge, beliefs or behaviours.

Results

Of 144 participants, 30 patients had ePA (two Liverpool epidemic strain, 28 Prairie epidemic strain), 83 % of which had established infection prior to transition to the adult clinic. Risk of concomitant infecting pathogens was no different between groups although, Staphylococcus aureus and non-tuberculous mycobacteria were less common in those with ePA. Patients with ePA were more likely to have attended CF-camp and have a history of CF fundraising. Patients with ePA did not differ with respect to beliefs regarding pathogens or transmission risk, except they believed indirect contact posed little risk. Furthermore, patients with ePA were more likely to continue to associate with others with CF despite extensive counselling. Use of peer-peer online networking was minimal in both groups.

Conclusion

Infections with ePA are closely linked to past exposures, now routinely discouraged. As socialization is the greatest risk factor for ePA, infection control strategies for ePA must focus on discouraging face-to-face interactions amongst CF patients. As peer support remains a desire amongst patients, investment in technologies and strategies that enable indirect communication and support are required.

Twenty-five-year outbreak of Pseudomonas aeruginosa infecting individuals with cystic fibrosis: identification of the prairie epidemic strain

Transmissible strains of Pseudomonas aeruginosa have been described for cystic fibrosis (CF) and may be associated with a worse prognosis. Using a comprehensive strain biobank spanning 3 decades, we sought to determine the prevalence and stability of chronic P. aeruginosa infection in an adult population. P. aeruginosa isolates from sputum samples collected at initial enrollment in our adult clinic and at the most recent clinic visit were examined by a combination of pulsed-field gel electrophoresis and multilocus sequence typing and compared against a collection of established transmissible and local non-CF bronchiectasis (nCFB) isolates. A total of 372 isolates from 107 patients, spanning 674 patient-years, including 66 patients with matched isolates from initial and final encounters, were screened. A novel clone with increased antibacterial resistance, termed the prairie epidemic strain (PES), was found in 29% (31/107 patients) of chronically infected patients referred from multiple prairie-based CF centers. This isolate was not found in those diagnosed with CF as adults or in a control population with nCFB. While 90% (60/66 patients) of patients had stable infection over a mean of 10.8 years, five patients experienced strain displacement of unique isolates, with PES occurring within 2 years of transitioning to adult care. PES has been present in our cohort since at least 1987, is unique to CF, generally establishes chronic infection during childhood, and has been found in patients at the time of transition of patients from multiple prairie-based CF clinics, suggesting broad endemicity. Studies are under way to evaluate the clinical implications of PES infection.

Inhalable microorganisms in Beijing's PM2.5 and PM10 pollutants during a severe smog event

Particulate matter (PM) air pollution poses a formidable public health threat to the city of Beijing. Among the various hazards of PM pollutants, microorganisms in PM2.5 and PM10 are thought to be responsible for various allergies and for the spread of respiratory diseases. While the physical and chemical properties of PM pollutants have been extensively studied, much less is known about the inhalable microorganisms. Most existing data on airborne microbial communities using 16S or 18S rRNA gene sequencing to categorize bacteria or fungi into the family or genus levels do not provide information on their allergenic and pathogenic potentials. Here we employed metagenomic methods to analyze the microbial composition of Beijing's PM pollutants during a severe January smog event. We show that with sufficient sequencing depth, airborne microbes including bacteria, archaea, fungi, and dsDNA viruses can be identified at the species level. Our results suggested that the majority of the inhalable microorganisms were soil-associated and nonpathogenic to human. Nevertheless, the sequences of several respiratory microbial allergens and pathogens were identified and their relative abundance appeared to have increased with increased concentrations of PM pollution. Our findings may serve as an important reference for environmental scientists, health workers, and city planners.

Caenorhabditis elegans: a model to monitor bacterial air quality

BACKGROUND

Low environmental air quality is a significant cause of mortality and morbidity and this question is now emerging as a main concern of governmental authorities. Airborne pollution results from the combination of chemicals, fine particles, and micro-organisms quantitatively or qualitatively dangerous for health or for the environment. Increasing regulations and limitations for outdoor air quality have been decreed in regards to chemicals and particles contrary to micro-organisms. Indeed, pertinent and reliable tests to evaluate this biohazard are scarce. In this work, our purpose was to evaluate the Caenorhaditis elegans killing test, a model considered as an equivalent to the mouse acute toxicity test in pharmaceutical industry, in order to monitor air bacterial quality.

FINDINGS

The present study investigates the bacterial population in dust clouds generated during crop ship loading in harbor installations (Rouen harbor, Normandy, France). With a biocollector, airborne bacteria were impacted onto the surface of agar medium. After incubation, a replicate of the colonies on a fresh agar medium was done using a velvet. All the replicated colonies were pooled creating the "Total Air Sample". Meanwhile, all the colonies on the original plate were isolated. Among which, five representative bacterial strains were chosen. The virulence of these representatives was compared to that of the "Total Air Sample" using the Caenorhaditis elegans killing test. The survival kinetic of nematodes fed with the "Total Air Sample" is consistent with the kinetics obtained using the five different representatives strains.

CONCLUSIONS

Bacterial air quality can now be monitored in a one shot test using the Caenorhaditis elegans killing test.

Managing cystic fibrosis: strategies that increase life expectancy and improve quality of life

The survival of patients with cystic fibrosis (CF) continues to improve. The discovery and cloning of the CFTR gene more than 21 years ago led to the identification of the structure and function of the CFTR chloride channel. New therapies based on the understanding of the function of CFTR are currently under development. The better clinical status and improved survival of patients with CF is not only a result of understanding of the molecular mechanisms of CF but also a result of the development of therapeutic strategies that are based on insights into the natural course of the disease. Current CF treatments that target respiratory infections, inflammation, mucociliary clearance, and nutritional status are associated with improved pulmonary function and reduced exacerbations. Patients benefit from treatment at a specialized CF center by a multidisciplinary dedicated team with emphasis being placed on frequent visits, periodic testing, and monitoring adherence to therapy. The purpose of this review is to survey recent developments in CF care that are responsible for the improved survival and quality of life of patients with CF.