• Klíčová slova
• Burkholderia, FT-IR, cystic fibrosis, epidemiology,
• MeSH
• Burkholderia cepacia komplex * MeSH
• Burkholderia * MeSH
• cystická fibróza * komplikace   MeSH
• infekce bakteriemi rodu Burkholderia * MeSH
• lidé MeSH
• spektroskopie infračervená s Fourierovou transformací metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• dopisy MeSH

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

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.

• Klíčová slova
• Cystic Fibrosis, Cystic Fibrosis Patient, Molecular Genetic Method, Multilocus Sequence Typing, recA Group,
• MeSH
• Burkholderia cepacia komplex klasifikace   genetika   izolace a purifikace   MeSH
• cystická fibróza epidemiologie   mikrobiologie   MeSH
• infekce bakteriemi rodu Burkholderia epidemiologie   mikrobiologie   MeSH
• lidé MeSH
• molekulární epidemiologie MeSH
• multilokusová sekvenční typizace MeSH
• prevalence MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH

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.

• MeSH
• bakteriemie mikrobiologie   MeSH
• biogeneze organel * MeSH
• Burkholderia cenocepacia genetika   fyziologie   MeSH
• cystická fibróza komplikace   mikrobiologie   MeSH
• dospělí MeSH
• flagella genetika   fyziologie   MeSH
• infekce bakteriemi rodu Burkholderia mikrobiologie   MeSH
• krev mikrobiologie   MeSH
• lidé MeSH
• lokomoce MeSH
• mikročipová analýza MeSH
• prognóza MeSH
• retrospektivní studie MeSH
• sputum mikrobiologie   MeSH
• stanovení celkové genové exprese * MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH

Burkholderia cenocepacia can cause serious infections and epidemics in patients with cystic fibrosis (CF). A CF population in the Czech Republic experienced an epidemic outbreak caused by a B. cenocepacia ST-32 strain. The clonality of the isolates was evident by multilocus sequence typing; however, fingerprinting profiles obtained by pulsed-field gel electrophoresis (PFGE) showed substantial band variability. We investigated whether the PFGE pattern diversity resulted from genomic rearrangements mediated by insertion sequences (IS); in addition, we determined whether stressful growth conditions altered the transposition activity of these IS. DNA probes for IS commonly found in B. cenocepacia were designed using the B. cenocepacia J2315 genome. Southern hybridization analysis of ST-32 isolates demonstrated diversity in both the copy number and the insertion site for a homologue of ISBcen20. Movement of the ISBcen20 homologue was detected when the ST-32 isolate CZ1238 was exposed to oxidative stress (growth in the presence of H(2)O(2)). PFGE analysis of CZ1238 derivatives exposed to oxidative stress demonstrated genomic rearrangements. Interestingly, when the closely related B. cenocepacia strain J2315 was exposed to oxidative stress, no movement of ISBcen20 was detected. Since frameshift mutations are present within the transposases of all copies of this IS in J2315, our data suggest that the transposase is inactive. In summary, we have demonstrated for the first time that IS movement can be mediated by oxidative stress and can lead to genomic rearrangements in the CF pathogen B. cenocepacia. These IS movements may alter the PFGE fingerprints of isolates that are clonal by other typing methods.

• MeSH
• Burkholderia klasifikace   genetika   izolace a purifikace   MeSH
• cystická fibróza komplikace   MeSH
• DNA bakterií genetika   MeSH
• DNA fingerprinting metody   MeSH
• epidemický výskyt choroby MeSH
• genetická variace * MeSH
• genotyp MeSH
• infekce bakteriemi rodu Burkholderia epidemiologie   mikrobiologie   MeSH
• lidé MeSH
• molekulární epidemiologie metody   MeSH
• oxidační stres * MeSH
• pulzní gelová elektroforéza metody   MeSH
• rekombinace genetická * MeSH
• shluková analýza MeSH
• techniky typizace bakterií metody   MeSH
• transpozibilní elementy DNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika epidemiologie   MeSH
• Názvy látek
• DNA bakterií MeSH
• transpozibilní elementy DNA MeSH