Monitoring of ECFS quality standards for the clinical management of adults with cystic fibrosis.

BACKGROUND: Although cystic fibrosis (CF) standards of care have been produced and regularly updated, they are not specifically targeting at the adult population. The ECFS Standards of Care Project established an international task force of experts to identify quality standards for adults with CF and assess their adherence. METHODS: This study was composed of two phases. In the first one, a task force of international experts derived from published guidelines and graded ten quality standards for adult CF care using a modified Delphi methodology. In the second phase, an international audit was conducted among adult CF centers to retrospectively validate the quality statements and monitor adherence. RESULTS: The task force identified 10 quality standards specific to the care of adults with CF, mainly based on the 2018 ECFS standards of care. 14 adult CF centers participated in the audit, which showed that most quality standards for the management of CF in adults are met across Europe. Heterogeneity in adherence to standards was found across centers according to geographical setting and centers' characteristics. CONCLUSIONS: The identification of quality standards is a valuable resource for the standardization and monitoring of care delivery across centers taking care of adults with CF.

Elexacaftor-tezacaftor-ivacaftor in patients with cystic fibrosis ineligible for clinical trials: a 24-week observational study.

Introduction: Seminal clinical trials with the triple combination of elexacaftor-tezacaftor-ivacaftor (ETI) demonstrated clinical efficacy in people with cystic fibrosis (pwCF) who carry at least one F508del mutation. However, due to exclusion criteria of these clinical trials, the effect of ETI was not studied in a substantial number of pwCF. Thus, we ran a single center trial to evaluate a clinical efficacy of ETI treatment in adult pwCF who were ineligible for enrollment in registration studies. Methods: PwCF on ETI with prior lumacaftor-ivacaftor therapy, severe airway obstruction, well-preserved lung function, or with airway infection with pathogens at risk of more rapid decline in lung function formed the study group, while all the others on ETI formed the control group. Lung function, nutritional status and sweat chloride concentration were assessed before and after initialization of ETI therapy over a 6-month period. Results: Approximately a half of the ETI-treated pwCF at the adult Prague CF center (49 of 96) were assigned to the study group. Their mean changes in body mass index ( + 1.04 kg/m2) and in sweat chloride concentration (-48.4 mmol/L) were similar to the control group ( + 1.02 kg/m2; -49.7 mmol/L), while the mean change in percent predicted forced expiratory volume in 1 s (ppFEV1; + 10.3 points) was significantly lower than in the control group ( + 15.8 points) (p = 0.0015). In the subgroup analysis, pwCF with severe airway obstruction (ppFEV1 <40) and pwCF with well-preserved lung function (ppFEV1 >90) showed a less potential for improvement in lung function during the ETI treatment than controls (median change in ppFEV1 + 4.9 points and + 9.5 points, respectively). Conclusion: PwCF not eligible for inclusion in clinical trials demonstrated improvement in lung function and nutritional status following the initiation of treatment with the ETI combination. Moderate increase in ppFEV1 was observed in those with severe airway obstruction or well-preserved lung function.

Significance of plasma fibrinogen and malondialdehyde in the post-inflammatory period in patients with cystic fibrosis.

OBJECTIVES: Evaluation of selected inflammatory parameters and serum malondialdehyde (MDA) significance in the post-inflammatory period in adult patients with cystic fibrosis. BACKGROUND: Laboratory biomarkers can be integrated into clinical practice as part of monitoring the effectiveness of treatment. METHODS: After recovery from an acute exacerbation of lung infection, selected inflammatory parameters (fibrinogen, IL-1, IL-6, SAA, hs-CRP) and serum MDA were examined in 30 adult patients with cystic fibrosis. Their correlation with FEV1, frequency and duration of subsequent hospitalizations and 6-year prognosis in terms of mortality or need for lung transplantation was evaluated. RESULTS: FEV1 negatively correlated with fibrinogen, but positively with MDA. No significant correlation with hs-CRP, IL-1, IL-6 and SAA was recorded. Plasma fibrinogen predicted the frequency and duration of subsequent hospitalizations. The 6-year prognosis was negatively associated with plasma fibrinogen whereas its association with MDA was positive. However, the prognosis of patients in the multivariate analysis was significantly associated only with FEV1. CONCLUSION: Plasma fibrinogen examined in the post-inflammatory period is a marker of lung damage in patients with cystic fibrosis and can be used to predict the prognosis. The positive correlation of serum MDA with FEV1 in the post-inflammatory period may be important to the interpretation of treatment interventions (Tab. 3, Fig. 2, Ref. 17).

Response to elexacaftor/tezacaftor/ivacaftor in intestinal organoids derived from people with cystic fibrosis.

Superior efficacy of elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) over tezacaftor/ivacaftor (TEZ/IVA) in people with cystic fibrosis (CF) and Phe508del/Phe508del genotype was shown in clinical trials. We utilized intestinal organoid approach to compare in vitro responses to these 2 CFTR modulator drug combinations and to check potential inter-individual variability in therapeutic response to the triple combination. Organoids from 17 subjects with Phe508del/Phe508del were screened with forskolin induced swelling assay. Significantly larger swelling, when exposed to ELX/TEZ/IVA as compared to TEZ/IVA, was observed in 16 of them. However, 1 sample showed no additional effect of ELX. The finding of unique CFTR variants in this sample indicates that genetic traits other than CF-causing CFTR mutation are worth exploring as they may have an impact on the definitive modulator drug response.

Biopsy of lung lesions under CT control.

OBJECTIVES: With the increasing number of detected lung nodules and the need for morphological verification, the number of CT- controlled biopsies is increasing. The aim of this study was to assess the risks and benefits of these biopsies. METHODS: This is a prospective and observational study. We evaluated 101 punctures performed on a group of 90 consecutive patients in the Department of Radiology. RESULTS: In patients with a mean age of 66 years, with mostly accidentally detected lung nodules, we observed complications 38 times. The most common were minor pneumothoraxes or insignificant bleedings. In 6 patients, the complications were more serious, 5 times the pneumothoraxes required chest drainage, once massive hemoptysis was recorded. The lesions were successfully biopsied 78 times, the target was missed 23 times. The diagnosis of lung cancer (LC) was confirmed in 60 patients, 49 LCs were verified by puncture under CT control. 42% (25/60) of patients with LC were diagnosed in TNM stages I and II. 23% (14/60) of patients with LC were treated surgically. The remaining 30 patients most often suffered from lung metastazes (13/30), in 8 of them an inflammatory lung disease was diagnosed. 69 patients underwent bronchoscopy, in only 19% (13/69) it contributed to the diagnosis. In a model "screening like" group of 49 patients with only randomly detected lung deposits, we diagnosed LC in 76% (37/49). 49% (18/37) were in TNM stage I and II, 11 were treated surgically. CONCLUSIONS: CT-controlled biopsy of lung lesions is an effective and safe diagnostic method.

Evaluation of TD test for analysis of persistence or tolerance in clinical isolates of Staphylococcus aureus.

Besides natural and acquired mechanisms of resistance, bacteria can cope with presence of antibiotics by using complex mechanisms such as persistence or tolerance. The main purpose of this study was to evaluate the suitability of newly developed Tolerance Disk Test (TDtest) (Gefen et al., 2017) to detect persistent or tolerant bacterial cells in clinical isolates of Staphylococcus aureus. The principle of the test is to resuscitate the subpopulation of persistent or tolerant bacterial cells following a disk diffusion test by glucose. Results of the TDtest were evaluated using time killing experiments for three pairs of consecutive S. aureus isolates from lower respiratory airway samples of three cystic fibrosis patients with chronic staphylococcal infections. TDtest enabled semi-quantitative detection of persistent or tolerant bacterial populations in all analyzed isolates for oxacillin, vancomycin, and ciprofloxacin to which isolates studied were susceptible. Therefore, TDtest is a promising method for rapidly determining persistence/tolerance in clinical isolates of S. aureus.

[Non-CF bronchiectasis of adults: short review for clinical practice Position paper of Board of disease with bronchial obstruction Czech Pulmonological and Phthiseological Society Czech Medical Association of J. E. Purkyne]. / Non-CF bronchiektázie dospelých: strucný prehled pro praxi Dokument Sekce chorob s bronchiální obstrukcí Ceské pneumologické a ftizeologické spolecnosti Ceské lékarské spolecnosti J. E. Purkyne.

Bronchiectasis is a clinically important, but poorly understood, pulmonary condition characterized by dilated and thick-walled bronchi. Bronchiectasis remains a significant cause of morbidity and mortality around the world. Targeted effort to early high-resolution computed tomography diagnosis and detailed confirmation of causation are in the spotlight of respiratory physicians in the developed countries. The risk population consists of subjects with persistent and/or productive cough, where another clear diagnosis has not been performed. Specific treatment tailored on underlying diseases and non-specific airway clearance techniques are able to improve symptoms, and reduce lung impairment. Evidence-based treatment algorithms for anti-inflammatory, and antibiotic treatment of stable non-CF BE will have to await large-scale, long-term controlled studies. Surgery should be reserved for individuals with highly symptomatic, localized bronchiectasis who have failed medical management. Unfortunately, there have been few well designed longitudinal or cross-sectional studies in the field of bronchiectasis. To give truly meaningful and generalizable results, a longitudinal observational study of bronchiectasis would require to enrol several thousand patients, more than any one center can enrol. The European Bronchiectasis Registry will create an open, pan-European registry of patients with non-CF bronchiectasis. The authors emphatically recommend that all respiratory specialist managed non-CF BE subjects should be actively involved in the European Bronchiectasis Registry.Key words: bronchiectasis - diagnosis - registry - treatment.

[Cystic fibrosis in adults]. / Cystická fibróza dospelých.

Cystic fibrosis (CF) is an inherited disease caused by mutations in the transmembrane conductance regulator (CFTR) gene. The disease leads to dysfunction of the exocrine glands with high concentration of chloride in the sweat and formation of abnormally viscous mucus in the respiratory, digestive and reproductive tract. Chronic sinopulmonary disease, exocrine pancreatic insufficiency, liver disease, intestinal obstruction, impaired nutritional status, salt loss syndrome and male infertility dominates in the clinical presentation. The examination of sweat chloride concentration and mutations in the CFTR gene is used in CF diagnostics for detection of CFTR protein dysfunction. The treatment comprises especially respiratory physiotherapy with mucolytics inhalations, aggressive antibiotic therapy and high-calorie diet together with adequate pancreatic enzymes substitution. The prevention of airway infection with resistant bacterial pathogens, particularly Pseudomonas aeruginosa, is a fundamental measure. Significant recent progress include the use of newborn screening of CF and drugs targeted to individual CFTR gene mutations in the clinical practise. The prognosis of patients has improved due to using of modern therapeutic methods in CF treatment centres. Children born at present time have survival probability 40-50 years.Key words: adults - cystic fibrosis - diagnostics - therapy.

What matters in chronic Burkholderia cenocepacia infection in cystic fibrosis: Insights from comparative genomics.

Burkholderia cenocepacia causes severe pulmonary infections in cystic fibrosis (CF) patients. Since the bacterium is virtually untreatable by antibiotics, chronic infections persist for years and might develop into fatal septic pneumonia (cepacia syndrome, CS). To devise new strategies to combat chronic B. cenocepacia infections, it is essential to obtain comprehensive knowledge about their pathogenesis. We conducted a comparative genomic analysis of 32 Czech isolates of epidemic clone B. cenocepacia ST32 isolated from various stages of chronic infection in 8 CF patients. High numbers of large-scale deletions were found to occur during chronic infection, affecting preferentially genomic islands and nonessential replicons. Recombination between insertion sequences (IS) was inferred as the mechanism behind deletion formation; the most numerous IS group was specific for the ST32 clone and has undergone transposition burst since its divergence. Genes functionally related to transition metal metabolism were identified as hotspots for deletions and IS insertions. This functional category was also represented among genes where nonsynonymous point mutations and indels occurred parallelly among patients. Another category exhibiting parallel mutations was oxidative stress protection; mutations in catalase KatG resulted in impaired detoxification of hydrogen peroxide. Deep sequencing revealed substantial polymorphism in genes of both categories within the sputum B. cenocepacia ST32 populations, indicating extensive adaptive evolution. Neither oxidative stress response nor transition metal metabolism genes were previously reported to undergo parallel evolution during chronic CF infection. Mutations in katG and copper metabolism genes were overrepresented in patients where chronic infection developed into CS. Among professional phagocytes, macrophages use both hydrogen peroxide and copper for their bactericidal activity; our results thus tentatively point to macrophages as suspects in pathogenesis towards the fatal CS.

Immunonutrition in patients with cyctic fibrosis leads to drop of serum amyloid A and increase of oxidative stress.

The aim of the present study is to evaluate of the impact of immunonutrition on parameters of oxidative stress and inflammation in patients with cystic fibrosis and malnutrition. In the 30 patients with cystic fibrosis and long-term enteral nutrition support for malnutrition the effect of standard and immunonutrion sipping on oxidative stress and inflammatory activity parameters was compared. Malonyldialdehyde (MDA) as parameter of oxidative stress and serum amyloid A (SAA), interleukin 1 and 6, hsCRP, IgM, IgA, IgG as parameters of inflammatory activity were examined. Immunonutrition decreased SAA to 17.6 mg/L comparing to 25.6 mg/L when standard nutrition was given (p = 0.014). MDA was 0.66 µM on standard and 0.96 µM on immunonutrition support (p<0.01). The significant negative correlation was recorded between MDA and SAA, hs-CRP, interleukin 6, IgA and IgG. In conclusion, the application of immunonutrition in patients with cystic fibrosis and malnutrition is associated with drop of SAA but with the rise of MDA.

Burkholderia cepacia complex in cystic fibrosis in the post-epidemic period: multilocus sequence typing-based approach.

Cystic fibrosis (CF) patients in the Czech Republic suffered in the late 1990s from an epidemic with ST32 strain of Burkholderia cepacia complex (Bcc). Cohort segregation of Bcc and of ST32 positive patients was introduced in 1999 and 2002, respectively. We performed a study to evaluate the molecular epidemiology of Bcc infection after implementation of these infection control measures. Patients attending the Prague CF adult Centre from 2000 to 2015 were included in the present study. Demographic data and microbial statuses were collected from patient records. All Bcc isolates were analyzed using multilocus sequence typing (MLST). The prevalences of epidemic strain ST32 and of other Bcc strains were calculated. Ninety out of 227 CF patients were infected with Bcc during the study period. The prevalence of ST32 cases significantly decreased from 46.5% in 2000-2001 to 10.4% in 2014-2015 (P < 0.001) due to occurrence of only one new case in 2003, as well as to the death of 72% of ST32-infected patients. Conversely, there was a significant increase in prevalence of other Bcc strains, which rose from 0 to 14.9% (P = 0.015) and of transient infections. A micro-epidemic of infection with ST630 strain was observed in 2014 in lung transplant patients hospitalized in intensive care unit. The prevalence of epidemic strain ST32 decreased, whereas that of non-clonal strains of Bcc increased. Routine use of MLST allowed early detection of new and potentially epidemic strains.

Cost-of-illness analysis and regression modeling in cystic fibrosis: a retrospective prevalence-based study.

BACKGROUND: Economic data pertaining to cystic fibrosis (CF), is limited in Europe generally, and completely lacking in Central and Eastern Europe. We performed an analysis of all direct costs associated with CF relative to key disease features and laboratory examinations. METHODS: A retrospective prevalence-based cost-of-illness (COI) study was performed in a representative cohort of 242 CF patients in the Czech Republic, which represents about 65 % of all Czech CF patients. Medical records and invoices to health insurance companies for reference year 2010 were analyzed. RESULTS: The mean total health care costs were €14,486 per patient, with the majority of the costs going towards medicinal products and devices (€10,321). Medical procedures (€2676) and inpatient care (€1829) represented a much smaller percentage of costs. A generalized linear model showed that the strongest cost drivers, for all cost categories, were associated with patient age and lung disease severity (assessed using the FEV1 spirometric parameter), when compounded by chronic Pseudomonas aeruginosa airway infections. Specifically, maximum total costs are around the age 16 years; a FEV1 increase of 1 % point represented a cost decrease of: 0.9 % (medicinal products), 1.7 % (total costs), 2.8 % (procedures) and 7.0 % (inpatient care). CONCLUSIONS: COI analysis and regression modeling using the most recent data available can provide a better understanding of the overall economic CF burden. A comparison of our results with other methodologically similar studies demonstrates that although overall costs may differ, FEV1 can nonetheless be utilized as a generally transferrable indicator of the relative economic impact of CF.

Continued Smoking in Lung Transplant Patients: A Cross Sectional Survey.

INTRODUCTION: Smoking is associated with a higher incidence of post-lung transplantation complications and mortality. Prior to inclusion on the lung transplant waiting list in the Czech Republic, patients are supposed to be tobacco free for at least 6 months. Our aim was to determine the prevalence of smoking, validated by urinary cotinine, among patients post lung transplantation and prior to inclusion on the transplant waiting list. METHODS: Between 2009 and 2012, we conducted a cross-sectional survey of urinary cotinine to assess tobacco exposure in 203 patients in the Lung Transplant Program in the Czech Republic. We measured urinary cotinine in 163 patients prior to inclusion on the transplantation waiting list, and 53 patients post bilateral lung transplantation. RESULTS: 15.1% (95% CI 0.078 to 0.269) of all lung transplant recipients had urinary cotinine levels corresponding to active smoking; and a further 3.8% (95% CI 0.007 to 0.116) had borderline results. Compared to patients with other diagnoses, patients with COPD were 35 times more likely to resume smoking post- transplantation (95% CI 1.92 to 637.37, p-value 0.016). All patients who tested positive for urinary cotinine levels were offered smoking cessation support. Only one Tx patient sought treatment for tobacco dependence, but was unsuccessful. CONCLUSION: Smoking resumption may be an underrecognized risk for lung transplantation recipients, particularly among patients with chronic obstructive pulmonary disease. More rigorous screening, as well as support and treatment to stop smoking among these patients are needed.

[Diagnostics of cystic fibrosis in adults]. / Diagnostika cystické fibrózy u dospelých.

INTRODUCTION: There is an increasing number of cystic fibrosis (CF) patients with the diagnosis established in adulthood worldwide. AIM: To give an overview of our experience with the diagnostics of CF in adulthood in the Czech Republic. METHODS: CF patients with the diagnosis determined at the age 18 years during 2000-2014 period were selected from the Czech Registry of CF (www.cfregistr.cz). Demographic and clinical data were reported from medi-cal records at the time of diagnosis and as of 31st December 2014. Only those with two CF causing mutation or with one CF causing mutation together with sweat chloride concentration > 60 mmol/l were included in the study. The clinical presentation was compared with a control group consisting of homozygous F508del patients with the diagnosis established in childhood. RESULTS: 23 patients (16 men and 7 women) with the diagnosis determined at a mean age of 32.9 ± 8.5 years were included in the study. Presenting symptoms included bronchiectasis and/or haemoptysis in 12 cases, obstructive azoospermia in 7 cases and recurrent pancreatitis in 4 cases. When compared with the control group, the patients had higher age (38.6 ± 8.3 vs. 28.3 ± 4.7 years; p < 0.001), a lower concentration of sweat chloride (62 ± 23 vs. 90 ± 12 mmol/l; p < 0.001), less frequent airway infections with Pseudomonas aeruginosa and/or Burkholderia cepacia complex (4 vs. 12; p = 0.029), bronchiectasis (14 vs. 23; p = 0.001), exocrine pancreatic insufficiency (1 vs. 23; p < 0.001) and therapy with insulin (1 vs. 9; p = 0.01); on the contrary, pancreatitis was more frequent (6 vs. 0; p = 0.022). CONCLUSION: Diagnosis of CF in adults should be considered in those with corresponding symptoms in respiratory, digestive and reproductive tract. Clinical presentation differs from classical CF in many parameters. KEY WORDS: adults - cystic fibrosis - diagnostics.

Ivacaftor in cystic fibrosis adults: Czech experience with six years of follow-up.

AIMS: Ivacaftor is a revolutionary treatment option for cystic fibrosis (CF) patients with G551D and other gating mutations. The aim of this study was to evaluate the clinical status of patients on ivacaftor who were followed for up to 6 years together with an evaluation of ivacaftor therapy in one patient with an initial FEV1 less than 40% of predicted value. METHODS: Data on development of clinical status and sinopulmonary-related therapies were obtained from patient health records during ivacaftor treatment lasting for up to six years and were compared with an equivalent period before ivacaftor administration. RESULTS: Five CF adults with a median age 28.6 years (range 21.4-35.6 years) with median FEV1 45% pred. (range 16-85% pred.) were included in the study. Four subjects were also participants in the STRIVE and PERSIST studies. Altogether, twenty-four patient-years of ivacaftor treatment were analyzed. The median FEV1 decline per year decreased from -4.5 to -0.9% pred. (P = 0.043). Reduction in number of days on antibiotic treatment and hospital stays was 21% (P < 0.001) and 75% (P = 0.003), respectively. Improvement and stabilization of lung function was observed for up to six years of treatment. In a patient with severe airway obstruction, an increase in the FEV1 value (30.4% from baseline) was documented during the first twelve months of treatment. CONCLUSION: Ivacaftor therapy resulted in improved and stabilized lung function in up to six years of treatment with a reduction in number of days on antibiotic treatment and hospital stays. Its efficiency was also displayed in a patient with severe airway obstruction.

Human Epididymis Protein 4: A Novel Serum Inflammatory Biomarker in Cystic Fibrosis.

BACKGROUND: Increased expression of the human epididymis protein 4 (HE4) was previously described in lung biopsy samples from patients with cystic fibrosis (CF). It remains unknown, however, whether serum HE4 concentrations are elevated in CF. METHODS: Seventy-seven children with CF from six Hungarian CF centers and 57 adult patients with CF from a Czech center were enrolled. In addition, 94 individuals with non-CF lung diseases and 117 normal control subjects with no pulmonary disorders were analyzed. Serum HE4 levels were measured by using an immunoassay, and their expression was further investigated via the quantification of HE4 messenger RNA by using quantitative reverse transcription polymerase chain reaction in CF vs non-CF respiratory epithelium biopsy specimens. The expression of the potential regulator miR-140-5p was analyzed by using an UPL-based quantitative reverse transcription polymerase chain reaction assay. HE4 was measured in the supernatants from unpolarized and polarized cystic fibrosis bronchial epithelial cells expressing wild-type or F508del-CFTR. RESULTS: Median serum HE4 levels were significantly elevated in children with CF (99.5 [73.1-128.9] pmol/L) compared with control subjects (36.3 [31.1-43.4] pmol/L; P < .0001). This observation was replicated in adults with CF (115.7 [77.8-148.7] pmol/L; P < .0001). In contrast, abnormal but lower HE4 concentrations were found in cases of severe bronchitis, asthma, pneumonia, and bronchiectasis. In patients with CF, the concentrations of HE4 were positively correlated with overall disease severity and C-reactive protein concentrations, whereas a significant inverse relationship was found between HE4 and the spirometric FEV1 value. Relative HE4 mRNA levels were significantly upregulated (P = .011) with a decreased miR-140-5p expression (P = .020) in the CF vs non-CF airway biopsy specimens. Twofold higher HE4 concentrations were recorded in the supernatant of polarized F508del-CF transmembrane conductance regulator/bronchial epithelial cells compared with wild-type cells. CONCLUSIONS: HE4 serum levels positively correlate with the overall severity of CF and the degree of pulmonary dysfunction. HE4 may thus be used as a novel inflammatory biomarker and possibly also as a measure of treatment efficacy in CF lung disease.

Lung cancer, pulmonary emphysema and pleural effusion: An autopsy study.

OBJECTIVES: To determine the exact incidence of lung cancer, pulmonary emphysema and pleural effusion we decided to carry out an autopsy study. METHODS: In this autopsy study carried out over two years, we compared the results of autopsy findings with the clinical data in accompanying records of the deceased. RESULTS: Among the 708 deceased subjects, there were 398 males and 310 females with a median age of 71 years. At autopsy, 55 cases of lung carcinoma (BCA) were found, of which 24 have not been identified during life (44%). Among the deceased with BCA, emphysema was also observed at autopsy in 40% of the cases. Pulmonary emphysema was described macroscopically in 28% of the full set of 708 deceased, whereas the accompanying records of the deceased described this condition in only 12% of the cases. Microscopic changes compatible with emphysema were identified in 54% of the examined lungs. Pleural effusions were described in the accompanying records of 13% of the deceased, while the autopsies showed this condition in 33% of the deceased. BCA was accompanied by effusion in 25% of the cases. CONCLUSIONS: The obtained results show that the studied conditions are present in more cases than are reported by clinicians. The study confirms the commonly accepted association between lung cancer and emphysema.

Characterization of Staphylococcus aureus Strains Isolated from Czech Cystic Fibrosis Patients: High Rate of Ribosomal Mutation Conferring Resistance to MLS(B) Antibiotics as a Result of Long-Term and Low-Dose Azithromycin Treatment.

Staphylococcus aureus is one of the most frequent pathogens infecting the respiratory tract of patients with cystic fibrosis (CF). This study was the first to examine S. aureus isolates from CF patients in the Czech Republic. Among 100 S. aureus isolates from 92 of 107 observed patients, we found a high prevalence of resistance to macrolide-lincosamide-streptogramin B (MLS(B)) antibiotics (56%). More than half of the resistant strains (29 of 56) carried a mutation in the MLS(B) target site. The emergence of MLS(B) resistance and mutations conferring resistance to MLS(B) antibiotics was associated with azithromycin treatment (p=0.000000184 and p=0.000681, respectively). Methicillin resistance was only detected in 3% of isolates and the rate of resistance to other antibiotics did not exceed 12%. The prevalence of small-colony variant (SCV) strains was relatively low (9%) and eight of nine isolates with the SCV phenotype were thymidine dependent. The study population of S. aureus was heterogeneous in structure and both the most prevalent community-associated and hospital-acquired clonal lineages were represented. Of the virulence genes, enterotoxin genes seg (n=52), sei (n=49), and sec (n=16) were the most frequently detected among the isolates. The PVL genes (lukS-PV and lukF-PV) have not been revealed in any of the isolates.

Gene expression profiling of Burkholderia cenocepacia at the time of cepacia syndrome: loss of motility as a marker of poor prognosis?

Cepacia syndrome (CS) is a fatal septic condition that develops in approximately 20% of cystic fibrosis (CF) patients chronically infected with the Burkholderia cepacia complex (Bcc). The most common causative agent is Burkholderia cenocepacia, a clinically dominant Bcc species that contains the globally distributed epidemic strain sequence type 32 (ST32). Using microarrays, we compared the transcriptomes of ST32 isolates from the bloodstream at the time of CS with their sputum counterparts recovered 1 to 2 months prior to the development of CS. Global gene expression profiles of blood isolates revealed greater activities of the virulence genes involved in the type III secretion system, the bacterial exopolysaccharide cepacian, and quorum sensing, while reduced expression was demonstrated for flagellar genes. Furthermore, a nonmotile phenotype (as evaluated by a swimming motility assay) was identified in blood isolates from 6 out of 8 patients with CS; this phenotype was traceable to 24 months prior to the onset of CS. Loss of motility was not observed in any of the 89 ST32 isolates recovered over the course of chronic infection from 17 patients without CS. In conclusion, the gene expression of Bcc bacteria disseminated during CS has been elucidated for the first time. This study demonstrated marked differences at the transcriptome level between isogenic ST32 isolates that are attributable to the stage and site of infection. The finding of a nonmotile B. cenocepacia isolate may serve as a warning sign for the development of CS in the near future.