Mucoid Pseudomonas Aeruginosa Research Articles

Curcumin-mediated photodynamic disinfection strategy with specific spectral range for mucoid Pseudomonas Aeruginosa from hospital water

BackgroundHospital water systems represent critical environments for the transmission of pathogens, including multidrug-resistant strains like mucoid Pseudomonas aeruginosa (M-PA). Conventional disinfection methods often struggle to eradicate these pathogens effectively, highlighting the need for innovative approaches. ObjectiveThis study aimed to develop an enhanced photodynamic disinfection strategy targeting M-PA from hospital water systems, using curcumin-mediated photodynamic inactivation (PDI) with specific spectral range. MethodsAn M-PA strain isolated from hospital water was subjected to photodynamic treatment using curcumin as the photosensitizer. The efficacy of different wavelengths of light and varying concentrations of curcumin, with and without Tris-EDTA adjuvants, was evaluated through bacterial enumeration, ROS level measurements, transcriptome analysis, and assessment of virulence factors and biofilm formation. In vivo experiments utilizing a DSS-induced colitis mouse model assessed the protective effects of the photodynamic treatment against M-PA infection. ResultsOur findings demonstrated that the combination of curcumin-mediated PDI with specific spectral range effectively reduced M-PA counts in water, particularly when supplemented with Tris-EDTA. Transcriptome analysis revealed significant downregulation of virulence-related genes under sublethal photodynamic conditions. Furthermore, photodynamic treatment inhibited pyocyanin production and biofilm formation in M-PA, highlighting its potential to disrupt pathogenicity mechanisms. In vivo experiments showed that PDI attenuated M-PA-induced colitis in mice, indicating its protective efficacy. ConclusionThis study presents a promising photodynamic disinfection strategy for combating M-PA from hospital water. By optimizing curcumin-mediated PDI with specific spectral range and adjuvants, our approach demonstrates substantial efficacy in reducing bacterial counts, inhibiting virulence factors, and preventing M-PA-associated colitis.

Pseudomonas aeruginosa mucinous phenotypes and algUmucABD operon mutant characteristics obtained from inpatients with bronchiectasis and their correlation with acute aggravation.

Although the mechanism is unclear, Pseudomonas aeruginosa (PA) infection directly affects the frequency of acute exacerbations in patients with bronchiectasis. The aims of this article are to analyze the genetic mutation characteristics of the algUmucABD operon in PA, isolated from hospitalized patients with bronchiectasis, and to explore independent risk factors for frequent acute exacerbations of bronchiectasis. Based on the number of acute exacerbations that occurred in the past year, these patients with bronchiectasis were divided into those with frequent acute exacerbations (Group A) and those with non-frequent acute exacerbations (Group B). We identified the distribution of mucoid phenotypes (MPs) and alginate morphotypes (AMs) in PA, and classified them into I-IV categories based on their different AMs; otherwise, the gene mutation types (GMTs) of the algUmucABD operon were tested. Subsequently, the relationship between GMT, MP, and AM and the independent risk factors for frequent acute exacerbations in patients with bronchiectasis were explored. A total of 93 patients and 75 PA strains, from January 2019 to August 2023, were included in this study. The MP and AM distributions of PA were as follows: 64 strains (85.33%) of mucoid (the AMs were 38 strains of type I, 3 strains of type II, and 23 strains of type IV) and 11 strains of non-mucoid (the AM was type III only). Mucoid PA with algU, mucA, mucB, and mucD mutations accounted for 19.61%, 74.51%, 31.37%, and 50.98%, respectively. GMT was divided into the following: mucA mutations only, mucA combined with other gene mutations, other gene mutations without mucA mutations, and without gene mutations. In 91.7% of PA with type I of AM, only mucA mutations occurred, and in both separate MP and AM, the GMT differences were statistically significant. Lastly, the number of lung lobes with bronchiectasis and the number of PA with mucA mutations only were the independent risk factors for frequent acute exacerbations. The mucA mutation was primarily responsible for the mucoid of MP and type I of AM in PA, and it was also an independent risk factor for frequent exacerbations of bronchiectasis.

The value of biofilm testing to guide antimicrobial stewardship in chronic respiratory diseases.

Biofilm production is an important yet currently overlooked aspect of diagnostic microbiology that has implications for antimicrobial stewardship. In this study, we aimed to validate and identify additional applications of the BioFilm Ring Test® (BRT) for Pseudomonas aeruginosa (PA) isolates from patients with bronchiectasis (BE). Sputa were collected from BE patients who had at least one PA positive culture in the previous year. We processed the sputa to isolate both mucoid and non-mucoid PA, and determined their susceptibility pattern, mucA gene status, and presence of ciprofloxacin mutations in QRDR genes. The Biofilm production index (BPI) was obtained at 5 and 24 hours. Biofilms were imaged using Gram staining. We collected 69 PA isolates, including 33 mucoid and 36 non-mucoid. A BPI value below 14.75 at 5 hours predicted the mucoid PA phenotype with 64% sensitivity and 72% specificity. Overall, our findings suggest that the fitness-cost associated with the mucoid phenotype or ciprofloxacin resistance is shown through a time-dependent BPI profile. The BRT has the potential to reveal biofilm features with clinical implications.

Microbiology rapid on-site evaluation: a better method for Mucoid Pseudomonas Aeruginosa diagnosis in bronchiectasic patients.

The aim of this study is to find an accurate and fast method to diagnose the pathogen of bronchiectasis. Ten bronchiectasic patients diagnosed with Mucoid Pseudomonas Aeruginosa (MPA) in the past two years were analyzed. Accuracy and time were compared between microbiology rapid on-site evaluation (M-ROSE) and sputum bacterial culture. The accuracy rate of M-ROSE in the patients is 100% consistent with bacterial culture results. The average time of M-ROSE is about 4.3 min, which is over 1000 times shorter than that of sputum bacterial culture. M-ROSE may be a better method for etiological diagnosis of MPA.

Anti-pseudomonas antibodies contribute to lung disease in cystic fibrosis.

Abstract Cystic fibrosis (CF) is an inherited lethal disease caused by mutations in CFTR. Approximately 60% of patients have homozygous F508del mutation, but their lung function is quite variable. Gene modifier studies identified I MHC II alleles are associated with the age of first Pseudomonas aeruginosa (PA) infection and lung function. Thus, we assessed serological responses to PA among CF subjects with poor lung function (FEV1<70%) versus good lung function (FEV1>90%). Immunoprecipitation-proteomics using outer membrane proteins (OMPs) from PA and human serum identified OprI as a potential important B cell antigen. We found increased anti-mucoid PA antibodies in CF and higher titers against OMPs and recombinant OprI in patients with poor lung function. Mice that were immunized with either recombinant OprI or inactivated whole PA subcutaneously developed high IgG titers in serum. Immunized mice that were challenged with mucoid PA had more weight loss and more severe lung pathology compared to unimmunized controls. There was minimal weight loss in PA immunized Rag2KO mice (impaired T and B cells), suggesting a role of adaptive immunity in the pathology. We observed more sensitive responses in FABP-hCFTR mice (CFTR knockout except GI tract) that OprI-immunized group exhibited the highest anti-OprI IgG titer and the most significant weight loss after challenge. These data suggest that one mechanism by which class II MHC is a modifier gene in CF is through antigen presentation and determining the types of anti-PA antibodies are generated in CF. Anti-PA antibodies may contribute to CF lung disease that we are conducting systems serology studies to understand which antibody functions are exacerbating disease.

Cystic Fibrosis Lung Transplant Recipients Have Suppressed Airway Interferon Responses during Pseudomonas Infection

SummaryLung transplantation can be lifesaving in end-stage cystic fibrosis (CF), but long-term survival is limited by chronic lung allograft dysfunction (CLAD). Persistent upper airway Pseudomonas aeruginosa (PsA) colonization can seed the allograft. While de novo PsA infection is associated with CLAD in non-CF recipients, this association is less clear for CF recipients experiencing PsA recolonization. Here, we evaluate host and pathogen contributions to this phenomenon. In the context of PsA infection, brushings from the airways of CF recipients demonstrate type 1 interferon gene suppression. Airway epithelial cell (AEC) cultures demonstrate similar findings in the absence of pathogens or immune cells, contrasting with the pre-transplant CF AEC phenotype. Type 1 interferon promoters are relatively hypermethylated in CF AECs. CF subjects in this cohort have more mucoid PsA, while non-CF PsA subjects have decreased microbiome α diversity. Peri-transplant protocols may benefit from consideration of this host and microbiome equilibrium.

Challenges and Promises for Planning Future Clinical Research Into Bacteriophage Therapy Against Pseudomonas aeruginosa in Cystic Fibrosis. An Argumentative Review.

Although early aggressive and prolonged treatment with specific antibiotics can extend survival in patients with cystic fibrosis (CF) colonized by opportunistic Pseudomonas aeruginosa (PA), antibiotics fail to eradicate the infecting multidrug-resistant (MDR) PA strains in CF. Century-long research has suggested treating patients with bacteriophages (phages, prokaryotic viruses) naturally hosted by bacteria. Although the only phage types used in therapy, lytic phages, lyse PA aggregated in biofilm matrix by depolymerase degrading enzymes, how they can effectively, safely, and persistently do so in patients with CF is unclear. Even though advanced techniques for formulating phage cocktails, training phages and collecting phage libraries have improved efficacy in vitro, whether personalized or ready-to-use therapeutic approaches or phages and antibiotics combined are effective and safe in vivo, and can reduce PA biofilms, remains debatable. Hence, to advance clinical research on phage therapy in clinical trials, also involving mucoid and non-mucoid multidrug-resistant PA in CF, and overcome problems in Western international regulations, we need reliable and repeatable information from experiments in vitro and in vivo on phage characterization, cocktail selection, personalized approaches, and phages combined with antibiotics. These findings, challenges, and promises prompted us to undertake this argumentative review to seek up-to-date information from papers describing lytic phage activity tested in vitro on PA laboratory strains, and PA strains from chronic infections including CF. We also reviewed in vivo studies on phage activity on pulmonary and non-pulmonary animal host models infected by laboratory or CF PA strains. Our argumentative review provides essential information showing that future phage clinical research in CF should use well-characterized and selected phages isolated against CF PA, tested in vitro under dynamic conditions in cocktails or combined with antibiotics, and in vivo on non-pulmonary and pulmonary host models infected with mucoid and non-mucoid CF MDR PA. Our findings should encourage pharmaceutical industries to conduct clinical trials in vitro and in vivo testing patented genomic engineered phages from phage libraries combined with antibiotics to treat or even prevent multidrug-resistant PA in CF, thus helping international regulatory agencies to plan future clinical research on phage therapy in CF.

Clinical and microbiological impact of inhaled tobramycin treatment on cystic fibrosis patients with Pseudomonas aeruginosa

Clinical and Microbiological Impact of Inhaled Tobramycin Treatment on Cystic Fibrosis Patients with Pseudomonas aeruginosa Francesca Dickhaus 1 , Mutasim Abu Hasan 2 , Elizabeth Tremblay 3 , Kenneth Klinker 4 , Kenneth Rand 5,6 Stacy G. Beal 5 1 University of Florida College of Medicine, Gainesville, Florida, USA 2 University of Florida College of Medicine, Department of Pediatrics, Pediatric Pulmonary and Allergy Division, Gainesville, Florida, USA 3 UF Health Shands Hospital, Department of Infection Control, Gainesville, Florida, USA 4 UF Health Shands Hospital, Department of Pharmacy Practice, Gainesville, Florida, USA 5 University of Florida College of Medicine, Department of Pathology, Immunology, and Laboratory Medicine, Gainesville, Florida, USA 6 University of Florida College of Medicine, Department of Internal Medicine, Division of Infectious Diseases and Global Medicine, Gainesville, Florida, USA ABSTRACT Objective: Patients’ with cystic fibrosis respiratory systems become colonized with pathogens as early as the first year of life. Some organisms are associated with a decline in pulmonary function and shortened survival, such as a mucoid strain of Pseudomonas aeruginosa (PA). Methods: We conducted a four year retrospective chart review study examining 158 pediatric and adult cystic fibrosis patients treated at an academic, tertiary care institution to compare patients treated by different antimicrobial regimens. Results: A higher proportion of mucoid PA study patients received alternate-monthly tobramycin therapy (83.3%), compared to those with non-mucoid PA (62.5%); although a large percentage of patients who had never had a mucoid PA infection were also receiving alternate-monthly tobramycin. Patients who had a mucoid PA infection had more hospitalizations and for longer periods of time than patients who had a non-mucoid PA infection; both mucoid and non-mucoid PA patients were hospitalized more often than patients who had never had a PA infection. We additionally found patients with mucoid PA infections to have strains that were either resistant or had intermediate resistance to tobramycin. Similar trends in resistance were not seen in patients who only received intermittent treatments with tobramycin. Conclusions Our findings on increased rates of infection with both Aspergillus (in the alternate-monthly inhaled tobramycin group) and NTM (in the overall patient population) comparative to international averages were also interesting, and open the doors to future research regarding CF patients with these infections. J Microbiol Infect Dis 2017; 7(4):178-185 Keywords: Cystic fibrosis, Pseudomonas, Tobramycin

The nature and role of autoimmunity in cystic fibrosis lung immunopathology

Abstract Cystic Fibrosis (CF) arises due to the altered activity of the CF transmembrane regulator (CFTR) protein. While the lung disease in CF is associated with chronic infection by Pseudomonas aeruginosa (PA), identical CFTR mutations exhibit considerable clinical variability. To elucidate this, we evaluated the autoantibody response to bactericidal permeability-increasing protein (BPI) and anti-citrullinated proteins (ACPA) in CF patients (n=38) and compared it with the autoantibody profile in sera from Rheumatoid Arthritis (RA) patients (n=50), given the association of airway inflammation with ACPA induction in RA. The presence of ACPA was restricted to RA patients; no antibodies to BPI were seen. In contrast, 42% of CF patients had anti-BPI IgG, but no ACPA. Contrary to ACPA, the autoantibodies to BPI did not bind to post-translationally modified epitopes but mapped to the protein C-terminus (CT-BPI). Patients with high levels of anti-BPI IgG exhibited worse lung function (lower FEV1), the presence of anti-Cif antibodies (CFTR inhibitory factor), and the absence of the homozygous F508del CFTR mutation. Neutrophil incubation with PA led to the cleavage of BPI into a ~32kDa fragment corresponding to CT-BPI, in an elastase dependent process. In addition, anti-BPI IgG levels were higher in patients harboring the more pathogenic (mucoid) PA strain infection. These findings prompt the model that autoantibody responses reflect greater impairment of PA clearance, which is the hallmark of this chronic inflammatory disorder. Alternatively, given that no clear association between bacterial colonization and CF disease severity exists, the model that autoantibodies independently exacerbate CF lung pathology merits consideration.

321 Changes in lung function and airway microbiology following ivacaftor therapy in an adult G551D homozygote

Objectives Ivacaftor has increased lung function and decreased pulmonary exacerbations and intravenous antibiotic use in patients with CF carrying the G551D mutation. This case study describes the effects of ivacaftor on airway microbiology and lung function in a G551D homozygote with chronic Pseudomonas aeruginosa (PA) infection. Methods All sputum culture reports prior to ivacaftor therapy were reviewed. Following ivacaftor initiation sputum samples were sent for standard culture at each clinic visit. 16S gene rRNA pyrosequencing was performed on paired sputum samples collected immediately prior to and after 6 months of ivacaftor therapy. FEV 1 was measured at baseline and at each follow up visit. Sweat chloride was assessed pre-treatment and at 6 months. Results Mucoid PA infection was acquired in 1983. The pre-ivacaftor baseline sputum sample and all preceding 26 samples taken over 8 years were culture positive for PA. 7 consecutive samples collected over 16 months following ivacaftor were culture negative for PA. A later sample was culture positive for the original infecting strain of PA (using variable number tandem repeat profiling). 16S gene rRNA pyrosequencing showed a drop in relative abundance of PA from 98.2% to 4.8% and an increase in microbial diversity over the 6 month sample period. FEV 1 improved from 68% predicted (baseline) to 90% predicted (20 months post ivacaftor). Sweat chloride reduced from 105 mmol/L (baseline) to 52 mmol/L (6months). Conclusion Bacterial diversity and relative abundance of typical CF pathogens may be significantly altered by modulation of both CFTR alleles. Sputum culture clearance of mucoid PA on should be interpreted with caution.

Chronic Infection by Mucoid Pseudomonas aeruginosa Associated with Dysregulation in T-Cell Immunity to Outer Membrane Porin F.

Pseudomonas aeruginosa (PA) is an environmental pathogen that commonly infects individuals with cystic fibrosis (CF) and non-CF bronchiectasis, impacting morbidity and mortality. To understand the pathobiology of interactions between the bacterium and host adaptive immunity and to inform rational vaccine design, it is important to understand the adaptive immune correlates of disease. To characterize T-cell immunity to the PA antigen outer membrane porin F (OprF) by analyzing immunodominant epitopes in relation to infection status. Patients with non-CF bronchiectasis were stratified by frequency of PA isolation. T-cell IFN-γ immunity to OprF and its immunodominant epitopes was characterized. Patterns of human leukocyte antigen (HLA) restriction of immunodominant epitopes were defined using HLA class II transgenic mice. Immunity was characterized with respect to cytokine and chemokine secretion, antibody response, and T-cell activation transcripts. Patients were stratified according to whether PA was never, sometimes (<50%), or frequently (≥50%) isolated from sputum. Patients with frequent PA sputum-positive isolates were more likely to be infected by mucoid PA, and they showed a narrow T-cell epitope response and a relative reduction in Th1 polarizing transcription factors but enhanced immunity with respect to antibody production, innate cytokines, and chemokines. We have defined the immunodominant, HLA-restricted T-cell epitopes of OprF. Our observation that chronic infection is associated with a response of narrowed specificity, despite strong innate and antibody immunity, may help to explain susceptibility in these individuals and pave the way for better vaccine design to achieve protective immunity.

In vitro and in vivo antibacterial activity of environmental bacteriophages against Pseudomonas aeruginosa strains from cystic fibrosis patients.

The goal of the study was to determine the relationship between in vitro/in vivo efficacy of environmental Pseudomonas phages and certain phenotypical properties of Pseudomonas aeruginosa (PA) strains. We studied the diversity between particular isolates and determined phage sensitivity in vitro and in vivo in the Galleria mellonella insect model. Twenty-eight lytic bacteriophages specific for PA were tested against 121 CF PA isolates including 29 mucoid PA strains. Most strains from cystic fibrosis (CF) patients were lysed by at least three phages (93.6 %), but completely insensitive strains were also present (6.4 %). Two phages PA5oct and KT28 exhibited high rates of lytic potency on 55–68 % of PA strains (72–86 % of mucoid isolates). We further explored phage activity against six PA strains (CF and non-CF) in vitro, comparing clonal differences in phage susceptibility with bacterial properties such as the ability to form biofilms, mucosity, twitching motility, and biochemical profiles. We observed the relationship between variation in phage susceptibility and Fourier transform infrared spectroscopy (FTIR) analysis in the spectra window of carbohydrates. The protective efficacy of two selected phages against PA PAO1 and 0038 infection was confirmed in vivo in G. mellonella larvae. Generally, the wax moth model results confirmed the data from in vitro assays, but in massive infection of CF isolates, the application of lytic phages probably led to the release of toxic compound causing an increase in larvae mortality. We assumed that apart of in vitro phage activity testing, a simple and convenient wax moth larvae model should be applied for the evaluation of in vivo effectiveness of particular phage preparations.

Increased rate of lung function decline in Australian adolescents with cystic fibrosis

Though baseline lung function as measured by spirometry in children with cystic fibrosis (CF) has improved, the annual rate of decline has not changed significantly during the critical period of adolescence. The aim of this study was to describe factors associated with longitudinal decline in lung function in a contemporary cohort of children with CF. Best annual lung function data from children attending the CF service of the Royal Children's Hospital Melbourne were reviewed to determine rate of decline in FEV(1) up until time of transfer to an adult center. Mixed models were used to determine the influence of age, sex, genotype, newborn screening, respiratory hospitalization, CF related diabetes mellitus (CFRD), pancreatic insufficiency, Pseudomonas aeruginosa (PsA) infection, and body mass index (BMI) on lung function decline. Longitudinal lung function data (range 5-20 years) were obtained for 98 patients with CF (55 male). Overall, the annual rate of decline in FEV(1) % predicted for the entire cohort was 1.4% per annum though the greatest rate of FEV1 decline was seen during adolescence (2.6%). Increasing age, homozygous ΔF508 genotype, CFRD, mucoid PsA infection, pancreatic insufficiency and respiratory hospitalizations were all significant predictors of FEV1 decline. FEV(1) declines at its sharpest rate during adolescence even in the presence of newborn screening. Genotype, increasing age, CFRD, PsA infection, pancreatic insufficiency and a greater number of respiratory hospitalizations are all associated with an increased rate of lung function decline in Australian children and adolescents with cystic fibrosis.

Screening for F508del as a first step in the molecular diagnosis of cystic fibrosis

OBJECTIVE: To determine the relevance of screening for the F508del mutation of the cystic fibrosis transmembrane conductance regulator gene as a first step in the genetic diagnosis of cystic fibrosis (CF) by associating the genotype with various clinical variables. METHODS: We evaluated 180 CF patients regarding the F508del mutation. The clinical data were obtained from the medical records of the patients and from interviews with their parents or legal guardians. RESULTS: Of the 180 patients studied, 65 (36.1%) did not carry the F508del mutation (group 0 [G0]), 67 (37.2%) were F508del heterozygous (G1), and 48 (26.7%) were F508del homozygous (G2). All three groups showed associations with the clinical variables. Homozygosis was associated with younger patients, younger age at CF diagnosis, and younger age at the first isolation of Pseudomonas aeruginosa (PA), as well as with higher prevalence of pancreatic insufficiency (PI) and non-mucoid PA (NMPA) colonization. In comparison with G1+G2 patients, G0 patients were older; first experienced clinical symptoms, digestive disease, and pulmonary disease at an older age; were older at CF diagnosis and at first PA isolation; and had a lower prevalence of PI and meconium ileus, as well as of colonization by NMPA, mucoid PA, and Burkholderia cepacia. In G1 patients, values were intermediate for age at CF diagnosis; age at first PA isolation, first pulmonary symptoms, and first clinical manifestations; MPA colonization; and OR for PI. CONCLUSIONS: The identification of F508del in 63.9% of the patients studied showed that this can be a useful tool as a first step in the genetic diagnosis of CF. The F508del genotype was associated with clinical severity of the disease, especially with the variables related to CF onset.

The production of stable defined cultures of mucoid Pseudomonas aeruginosa in continuous culture [proceedings

The production of stable defined cultures of mucoid Pseudomonas aeruginosa in continuous culture [proceedings

Rhinovirus infection liberates planktonic bacteria from biofilm and increases chemokine responses in cystic fibrosis airway epithelial cells

BackgroundIntermittent viral exacerbations in patients with cystic fibrosis (CF) with chronic Pseudomonas aeruginosa (PA) infection are associated with increased bacterial load. A few clinical studies suggest that rhinoviruses (RV) are...

Can mucoid Pseudomonas aeruginosa be eradicated in children with cystic fibrosis?

Pseudomonas aeruginosa (PsA) is the most common pathogen to cause chronic lung infection in children with cystic fibrosis (CF), and is associated with an increase in both morbidity and mortality. Whilst the non-mucoid strain can be eradicated, it is believed that mucoid PsA is difficult, if not impossible, to eradicate. We hypothesized that with modern and aggressive antibiotic regimes, mucoid PsA can be eradicated in children with CF. We investigated this hypothesis through a retrospective review of respiratory tract cultures of children with CF at The Royal Brompton Hospital, London. Children aged under 16 with a confirmed diagnosis of CF and mucoid PsA on respiratory tract culture during a defined 9-year period were eligible for inclusion. Respiratory tract culture results were followed up for each patient to establish whether children remained infected with mucoid PsA and specifically to identify clearance of infection. Factors which may have been associated with persistence or clearance were also sought. One hundred sixteen children had the minimum dataset, and of these patients 67 (58%) cleared mucoid PsA for more than 1 year. Of the 67 patients who cleared mucoid PsA for more than 1 year, 38 (57%) patients remained clear of mucoid PsA at the last available culture (median 30, range 2-106 clear cultures, and median 55, 12-103 months clear). We conclude that isolation of mucoid PsA does not necessarily equate to lifelong infection. We suggest that trials of eradication of mucoid PsA at first isolation are required.

Segregation of children with CF diagnosed via newborn screening and acquisition of Pseudomonas aeruginosa

Background Data from the Wisconsin newborn screening (NBS) study show that neonatally diagnosed infants are at risk of early Pseudomonas aeruginosa ( PsA) acquisition. We have had NBS since 1981 and in 2003, introduced PsA-free ‘segregation’ from older patients for children ≤ 5. This study investigated the effect of simple ‘segregation' on acquisition of respiratory pathogens. Methods Sputum culture results ( n = 2814) and details of antibiotic use before (1999–2002) and after (2004–2007) ‘segregation’ were collected. Results Each year each child provided an average of 4.6 samples for culture. There was a significant decrease ( p ≤ 0.001 Chi 2) in the acquisition of mucoid (from 5.9% of children to 1.0%) but not non-mucoid PsA (22.3% and 22.7%, respectively) after ‘segregation’. There was no significant change in other respiratory pathogens. Conclusions Young children with CF diagnosed via NBS can be protected from the acquisition of mucoid PsA by ‘segregation’ and the acquisition of non-mucoid PsA is likely to be from environmental sources outside the hospital.

Association between MucoidPseudomonasInfection and Bronchiectasis in Children with Cystic Fibrosis

To correlate the severity of bronchiectasis in children with cystic fibrosis with clinical and microbiologic variables in order to clarify risk factors for the development of irreversible lung disease. After institutional review board approval and parental informed consents were obtained, a HIPAA-compliant longitudinal epidemiologic evaluation was performed in patients with cystic fibrosis who were enrolled in the Wisconsin trial of newborn screening from 1985 to 2009. Thin-section chest computed tomography (CT) was used in a prospective cross-sectional design to study patients ranging in age from 6.6 to 17.6 years (mean, 11.5 years). Thin-section CT scores were determined objectively on coded images by multiple raters in a standardized fashion. Microbiologic data were obtained by means of culture of respiratory secretions by using methods for differentiation of Pseudomonas aeruginosa (PA) as either nonmucoid or mucoid. Eighty-three percent of patients (68 of 82) showed bronchiectasis of varying severity. Of 12 potential risk factors, only respiratory infection with mucoid PA correlated significantly with bronchiectasis (P = .041). The severity of bronchiectasis in children with cystic fibrosis is significantly related to respiratory infection with mucoid PA; attempts to prevent bronchiectasis should include reducing exposure to and early eradication of PA.

Mucoid Pseudomonas aeruginosa, TNF-alpha, and IL-1beta, but not IL-6, induce human beta-defensin-2 in respiratory epithelia.

Cultured lung epithelial cells release antibacterial activity upon contact with Pseudomonas aeruginosa (PA), which is impaired in cystic fibrosis (CF). In order to identify the factors responsible for killing PA by a biochemical approach, we purified antimicrobial activity from supernatants of the A549 lung epithelial cell line, previously stimulated with PA bacteria, by subsequent high performance liquid chromatography. NH(2)-terminal sequencing of a major bactericidal compound revealed it to be identical with human beta-defensin-2 (hBD-2). A mucoid phenotype of PA, but not two nonmucoid PA strains, high concentrations (> 10 microg/ml) of PA lipopolysaccharide, tumor necrosis factor alpha, and interleukin (IL)-1beta, but not IL-6, dose-dependently induced hBD-2 messenger RNA in cultured normal bronchial, tracheal, as well as normal and CF-derived nasal epithelial cells. Genomic analysis of hBD-2 revealed a promoter region containing several putative transcription factor binding sites, including nuclear factor (NF) kappaB, activator protein (AP)-1, AP-2, and NF-IL-6, known to be involved in the regulation of inflammatory responses. Thus, hBD-2 represents a major inducible antimicrobial factor released by airway epithelial cells either on contact with mucoid PA or by endogenously produced primary cytokines. Therefore, it might be important in lung infections caused by mucoid PA, including those seen in patients with CF.