[Detection of Burkholderia cepacia complex strains in the University Hospital Olomouc]. / Záchyt kmenu Burkholderia cepacia komplex ve Fakultní nemocnici Olomouc.

BACKGROUND: The aim was to assess the epidemiology of Burkholderia cepacia complex strains isolated at the Department of Microbiology, Faculty of Medicine and Dentistry, Palacky University and University Hospital Olomouc, determine the most frequent strains and confirm or rule out potential clonal spread of the strains. MATERIAL AND METHODS: Over a period of eight months, all strains classified as Burkholderia cepacia complex were collected. Susceptibility to selected antimicrobial agents was determined and adequate molecular genetic methods were used to assess their genetic relationship. RESULTS: A total of 52 isolates were tested, with the most frequent (88.5 %) being genomovar II (Burkholderia multivorans). More than 46 % of them were genetically related; 58.3 % of them were detected in intensive care units. All isolates were highly resistant to antimicrobial agents. In four cases, deaths associated with Burkholderia multivorans infection were reported. CONCLUSION: It may be assumed that genetically related strains of Burkholderia multivorans spread from the hospital setting. As yet, the source of infection has not been determined and further investigations are needed.

Enteral feeding reduces metabolic activity of the intestinal microbiome in Crohn's disease: an observational study.

BACKGROUND/OBJECTIVES: Enteral feeding will induce remission in as many as 80-90% of compliant patients with active Crohn's disease (CD), but its method of action remains uncertain. This study was designed to examine its effects on the colonic microbiome. METHODS/SUBJECTS: Healthy volunteers and patients with CD followed a regimen confined to enteral feeds alone for 1 or 2 weeks, respectively. Chemicals excreted on breath or in faeces were characterised at the start and at the end of the feeding period by gas chromatography/mass spectrometry. RESULTS: One week of feeding in healthy volunteers caused significant changes in stool colour and deterioration in breath odour, together with increased excretion of phenol and indoles on the breath. Feeding for 2 weeks in patients with CD produced significant improvements in symptoms and a decrease in the concentration of C-reactive protein. The faecal concentrations of microbial products, including short-chain fatty acids (SCFAs), and potentially toxic substances, including 1-propanol, 1-butanol and the methyl and ethyl esters of SCFAs, showed significant falls. CONCLUSIONS: A significant change occurs in the production of microbial metabolites after enteral feeding in both healthy volunteers and patients with CD. Many of those detected in CD are toxic and may feasibly lead to the immunological attack on the gut microbiota, which is characteristic of inflammatory bowel disease. The reduction in the production of such metabolites after enteral feeding may be the reason for its effectiveness in CD.

An outbreak of Burkholderia multivorans beyond cystic fibrosis patients.

Strains of the Burkholderia cepacia complex (Bcc) are opportunistic pathogens capable of causing serious infection in cystic fibrosis patients. Recently we identified a suspected outbreak of infection with Bcc strains at the University Hospital Olomouc. Seventy-four Bcc strains were isolated from 52 patients, most of whom (N = 48) did not suffer from cystic fibrosis. Most frequently (N = 46) Burkholderia multivorans was isolated and 24 (52.2%) of these strains were clonal. Fifteen of these strains were isolated from intensive care patients, five of whom died from hospital-acquired pneumonia. B. multivorans can cause serious outbreaks of infection beyond cystic fibrosis sufferers.

Different responses to nitrate and nitrite by the model organism Escherichia coli and the human pathogen Neisseria gonorrhoeae.

The ability of Escherichia coli to use both nitrate and nitrite as terminal electron acceptors during anaerobic growth is mediated by the dual-acting two-component regulatory systems NarX-NarL and NarQ-NarP. In contrast, Neisseria gonorrhoeae responds only to nitrite: it expresses only NarQ-NarP. We have shown that although N. gonorrhoeae NarQ can phosphorylate E. coli NarL and NarP, the N. gonorrhoeae NarP is unable to regulate gene expression in E. coli. Mutagenesis experiments have revealed residues in E. coli NarQ that are essential for nitrate and nitrite sensing. Chimaeric proteins revealed domains of NarQ that are important for ligand sensing.