A case of epidemic keratoconjunctivitis complicated by Alcaligenes xylosoxidans infection.
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PURPOSE: To report a case of epidemic keratoconjunctivitis complicated by Alcaligenes xylosoxidans. METHODS: A 37-year-old man suffered epidemic keratoconjunctivitis in both eyes. Eleven days later, he developed a corneal ulcer in his left eye. Bacterial staining, culture, and antibiotics sensitivity test were performed from a corneal scrape. RESULTS: The cultures revealed a growth of Alcaligenes xylosoxidans, and the patient was treated with ceftazidime and levofloxacin, based on the sensitivity test results. After 21 days of treatment, the infection was resolved with mild scaring and final vision in the left eye of 20/20. CONCLUSIONS: Alcaligenes xylosoxidans should be considered a rare but potential pathogen able to produce comeal ulcer complication in epidemic keratoconjunctivitis. (+info)
Chronic infection with Achromobacter xylosoxidans in cystic fibrosis patients; a retrospective case control study.
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BACKGROUND: In cystic fibrosis (CF), chronic infection of the airways with Achromobacter xylosoxidans have become more frequent. The pathogenic role of this is yet unclear. METHODS: A retrospective case-control study of all patients chronically infected with A. xylosoxidans for at least 3 years. 15 patients (6 males) with chronic A. xylosoxidans infection were matched by age, FEV(1) and body mass index z-score to 15 controls (7 males) at the time of establishment of chronic infection. Clinical parameters of the groups were compared from the time of establishment of chronic infection until spring 2006, giving a follow-up time of 3-11 years. Chest X-rays taken 3 years prior to establishment of chronic infection and after 3 years of chronic infection were compared using a modified Brasfield score. Finally, strains from individual patients were analysed using PFGE to investigate possible cross-infection. RESULTS: The median slope of decline of FEV(1) in the case group changed from +3.1% to -0.5% predicted/year (p<0.002). In the control group, median slope of decline in FEV(1) changed from +1.5% to -0.4% predicted/year (n.s.). Median slope of decline in FVC in the case group changed from +3.5% to -0.5% predicted/year (p<0.002). In the control group, median slope of decline in FVC changed from +1.7% to +0.4% predicted/year (n.s.). No significant difference in the slopes of decline of FEV(1) or FVC was found between the case group and the control group at either time. Change in BMI z-score was calculated for each group before and during chronic infection. No difference was found between the groups at any time or within a group. Specific antibodies against A. xylosoxidans were measured in patients with chronic infection. Patients with rapidly increasing antibody levels showed significantly faster deterioration in FEV(1) (p<0.05) and FVC (p<0.02). Chest X-ray scores increased in 6 of 10 chronically infected patients and in 3 of 10 controls (n.s.). Eight patients harboured a common A. xylosoxidans strain, indicating either cross-infection or a common source. CONCLUSION: A. xylosoxidans may lead to a decline in lung function in a subgroup of chronically infected CF patients characterised by a rapid increase in specific precipitating antibodies. Cross-infection may possibly occur. (+info)
Achromobacter xylosoxidans in cystic fibrosis: prevalence and clinical relevance.
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BACKGROUND: Achromobacter xylosoxidans is increasingly cultured in sputum from cystic fibrosis (CF) patients; nevertheless, there are few published data on the clinical impact of this infection or chronic colonisation. METHODS: Relying on DNA fingerprinting techniques we studied the prevalence of A. xylosoxidans in our CF population. In a retrospective case control study the clinical status of patients with at least 3 sputum cultures positive for A. xylosoxidans over at least 9 months, at the moment of the first positive culture and during the period of colonisation were compared to age (+/-1 year), gender and to Pseudomonas aeruginosa colonisation controlled CF patients who had never A. xylosoxidans positive sputum cultures. RESULTS: The prevalence of patients with at least one positive A. xylosoxidans culture was 17.9%. 5.3% of the patients fulfilled the criteria of our definition of colonisation. Colonised patients had a median age of 20 years (range 11-27 years) and a mean colonisation period of 1.5 (+/-0.9) years. At the moment of the first positive culture we found significantly lower Bhalla scores on HRCT scans of the lungs (11+/-3 versus 16+/-3, p<0.002), lower Brasfield chest X-ray scores (14+/-3 versus 18+/-3, p<0.019), lower FVC values (70%+/-22 versus 94%+/-12, p<0.017) and lower FEV(1) values (55%+/-32 versus 78%+/-23, p=0.123), although the latter did not reach significance. There was no significant difference in body mass index (BMI) (18.7+/-3 kg/m2 versus 19.6+/-3 kg/m2, p=0.8). Over the study period A. xylosoxidans-colonised patients did have more need for intravenous antibiotic treatment courses (19 versus 5, p<0.001); nevertheless, there was no significant difference in lung function decline over the study period (FVC: -6.25+/-12.34% versus -5.62+/-8.30%, p 0.77, FEV1: -5.62+/-8.30% versus -1.87+/-11.58%, p<0.47). CONCLUSIONS: The prevalence of A. xylosoxidans infection or colonisation is probably underestimated. Colonised patients are mostly older, with more pronounced lung damage and lower lung function values. Although there was more need for intravenous antibiotic treatment courses, no faster decline in lung function was observed in A. xylosoxidans positive patients. (+info)
Fluorescence in situ hybridization for rapid identification of Achromobacter xylosoxidans and Alcaligenes faecalis recovered from cystic fibrosis patients.
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Achromobacter xylosoxidans is frequently isolated from the respiratory secretions of cystic fibrosis (CF) patients, but identification with biochemical tests is unreliable. We describe fluorescence in situ hybridization assays for the rapid identification of Achromobacter xylosoxidans and Alcaligenes faecalis. Both assays showed high sensitivities and high specificities with a collection of 155 nonfermenters from CF patients. (+info)
The preparation of a lipidic endotoxin affects its biological activities.
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Bacterial membrane constituents, such as Ornithine-containing lipid (OL) and the lipid A portion of lipopolysaccharide, trigger various immune responses through recognition by Toll-like receptor (TLR) 4. Usually, these lipids are dissolved in a small amount of aqueous or organic solvent before being added to the culture medium for examination of their biological activities. Macrophages stimulated with OL or lipid A sonically dissolved in saline released both interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). In contrast, macrophages stimulated with OL or lipid A sonically dissolved in ethanol or dimethyl sulfoxide (DMSO) secreted much TNF-alpha, but very little IL-1beta. These results, taken together, indicate that how an endotoxin is prepared affects its biological activities. In addition, electromicroscopic analysis revealed that sonication of air-dried OL or lipid A in DMSO produced larger particles than those produced in saline, suggesting that the process of preparing lipidic TLR4-ligands affects their physical state including particle size, and that the physical state might be an important determinant of biological activity. (+info)
Molecular characterization of lysine 6-dehydrogenase from Achromobacter denitrificans.
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An inducible lysine 6-dehydrogenase (Lys 6-DH), which catalyzes the oxidative deamination of the 6-amino group of L-lysine in the presence of NAD(+), was purified to homogeneity from Achromobacter denitrificans, yielding a homodimeric protein of 80 kDa. The enzyme was specific for the substrate L-lysine and NAD(+) served as a cofactor. The dimeric enzyme associated into a hexamer in the presence of 10 mM L-lysine. The K(m) values for L-lysine and NAD(+) were 5.0 and 0.09 mM, respectively. The lys 6-dh gene was cloned and overexpressed in E. coli. The open reading frame was 1,107 nucleotides long and encoded a peptide containing 368 amino acids with 39,355 Da. The recombinant enzyme was purified to homogeneity and characterized. Enzyme activities and kinetic properties of the recombinant enzyme were almost the same as those of the endogenous enzyme obtained from A. denitrificans. Crystals of the enzyme were obtained using the hanging drop method. (+info)