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.

• MeSH
• Burkholderia cenocepacia genetika   MeSH
• chronická nemoc MeSH
• cystická fibróza komplikace   mikrobiologie   MeSH
• infekce bakteriemi rodu Burkholderia genetika   MeSH
• infekce dýchací soustavy mikrobiologie   MeSH
• lidé MeSH
• srovnávací genomová hybridizace MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The association between oxidative stress and neutrophilic inflammation in cystic fibrosis (CF) lung disease is well recognized. 8-Isoprostane is a product of non-enzymatic oxidation of arachidonic acid. The aim of the present study was to examine the relationship between lung function decline and 8-isoprostane concentrations in exhaled breath condensate (EBC) in CF patients with Burkholderia cenocepacia airway colonization. Concentrations of 8-isoprostane in EBC were measured in 24 stable CF patients with B. cenocepacia airway colonization. The median (interquartile range) age of the cohort was 23.9 (22.0; 26.6) years. All patients underwent clinical examinations and pulmonary function tests at the time of EBC collection and in 1-, 3-, and 5-year intervals. 8-Isoprostane concentrations in EBC correlated to 1- and 3-year declines of forced expiratory volume in 1 s (FEV1) with r(S) values of -0.511 (p = 0.0011) and -0.495 (p = 0.016), respectively. In multiple regression analysis, 8-isoprostane concentrations in EBC were the only independent predictor for 1-year FEV1 decline (p = 0.01). When the median value of 8-isoprostane concentration in EBC (10.0 pg/mL) was used as a cutoff, subgroups of patients with lower and higher level of oxidative stress had significantly different median (interquartile range) FEV1 declines in 1-year interval, -2.4% (-5.3; 0.8) and -7.3% (-10.3; -5.8) predicted (p = 0.009). In conclusion, 8-isoprostane concentrations in EBC correlated to short-term lung function decline in CF patients with B. cenocepacia airway colonization. This correlation reflects the role of oxidative stress in CF lung pathogenesis and contributes to prediction of prognosis in these patients.

• MeSH
• Burkholderia cenocepacia * MeSH
• časové faktory MeSH
• cystická fibróza komplikace   metabolismus   patofyziologie   MeSH
• dinoprost analogy a deriváty   metabolismus   MeSH
• dospělí MeSH
• infekce bakteriemi rodu Burkholderia komplikace   mikrobiologie   MeSH
• lidé MeSH
• mladý dospělý MeSH
• oportunní infekce * MeSH
• oxidační stres * MeSH
• respirační funkční testy MeSH
• usilovný výdechový objem MeSH
• vydechnutí MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 8-epi-prostaglandin F2alpha MeSH Prohlížeč
• dinoprost MeSH