Biomedical subjects

P Vandamme

Publications and source records attributed to P Vandamme.

At least 19 recordsLinked to original sources

PubMed2006

Helicobacter cynogastricus sp. nov., isolated from the canine gastric mucosa.

A Gram-negative, microaerophilic helical rod, isolated from the gastric mucosa of a dog and designated strain JKM4(T), was subjected to a polyphasic taxonomic study. The tightly coiled organism, measuring 10-18 mum long and up to 1 mum wide, was motile by means of multiple sheathed flagella located at both ends of the cell and by a periplasmic fibril running along the external side of the helix. Strain JKM4(T) grew preferably on biphasic culture plates or on very moist agar. Coccoid forms predominated in cultures older than 4 days as well as in growth obtained on dry agar plates. The strain grew at 30 and 37 degrees C, but not at 25 or 42 degrees C and exhibited urease, oxidase and catalase activities. On the basis of 16S rRNA gene sequence analysis, the novel isolate was identified as a member of the genus Helicobacter and showed > 97 % similarity to Helicobacter felis, Helicobacter bizzozeronii and Helicobacter salomonis, three species previously isolated from the canine gastric mucosa. Protein profiling of strain JKM4(T) using SDS-PAGE revealed a pattern different from those of other Helicobacter species of mammalian gastric origin and from Helicobacter canis. Additionally, the urease gene sequence of strain JKM4(T) was different from those of urease genes of H. felis, H. bizzozeronii, H. salomonis and "Candidatus Helicobacter heilmannii". It is thus proposed that strain JKM4(T) (=LMG 23188(T)) represents a novel species within this genus, Helicobacter cynogastricus sp. nov.

Animals↗

PubMed2005

Burkholderia phytofirmans sp. nov., a novel plant-associated bacterium with plant-beneficial properties.

A Gram-negative, non-sporulating, rod-shaped, motile bacterium, with a single polar flagellum, designated strain PsJN(T), was isolated from surface-sterilized onion roots. This isolate proved to be a highly effective plant-beneficial bacterium, and was able to establish rhizosphere and endophytic populations associated with various plants. Seven related strains were recovered from Dutch soils. Based on 16S rRNA gene sequence data, strain PsJN(T) and the Dutch strains were identified as representing a member of the genus Burkholderia, as they were closely related to Burkholderia fungorum (98.7 %) and Burkholderia phenazinium (98.5 %). Analysis of whole-cell protein profiles and DNA-DNA hybridization experiments confirmed that all eight strains belonged to a single species. Strain PsJN(T) had a DNA G+C content of 61.0 mol%. Only low levels of DNA-DNA hybridization to closely related species were found. Qualitative and quantitative differences in fatty acid composition between strain PsJN(T) and closely related species were identified. The predominant fatty acids in strain PsJN(T) were 16 : 0, 18 : 1omega7c and summed feature 3 (comprising 16 : 1omega7c and/or iso-15 : 0 2-OH). Isolate PsJN(T) showed high 1-aminocyclopropane-1-carboxylate deaminase activity and is therefore able to lower the ethylene level in a developing or stressed plant. Production of the quorum-sensing signal compound 3-hydroxy-C8-homoserine lactone was detected. Based on the results of this polyphasic taxonomic study, strain PsJN(T) and the seven Dutch isolates are considered to represent a single, novel species, for which the name Burkholderia phytofirmans sp. nov. is proposed. The type strain is strain PsJN(T) (=LMG 22146(T) = CCUG 49060(T)).

4-Butyrolactone↗

PubMed2005

Transmission of Burkholderia cepacia complex: evidence for new epidemic clones infecting cystic fibrosis patients in Italy.

To analyze national prevalence, genomovar distribution, and epidemiology of the Burkholderia cepacia complex in Italy, 225 putative B. cepacia complex isolates were obtained from 225 cystic fibrosis (CF) patients attending 18 CF centers. The genomovar status of these isolates was determined by a polyphasic approach, which included whole-cell protein electrophoresis and recA restriction fragment length polymorphism (RFLP) analysis. Two approaches were used to genotype B. cepacia complex isolates: BOX-PCR fingerprinting and pulsed-field gel electrophoresis (PFGE) of genomic macrorestriction fragments. A total of 208 (92%) of 225 isolates belonged to the B. cepacia complex, with Burkholderia cenocepacia as the most prevalent species (61.1%). Clones delineated by PFGE were predominantly linked to a single center; in contrast, BOX-PCR clones were composed of isolates collected either from the same center or from different CF centers and comprised multiple PFGE clusters. Three BOX-PCR clones appeared of special interest. One clone was composed of 17 B. cenocepacia isolates belonging to recA RFLP type H. These isolates were collected from six centers and represented three PFGE clusters. The presence of insertion sequence IS 1363 in all isolates and the comparison with PHDC reference isolates identified this clone as PHDC, an epidemic clone prominent in North American CF patients. The second clone included 22 isolates from eight centers and belonged to recA RFLP type AT. The genomovar status of strains with the latter RFLP type is not known. Most of these isolates belonged to four different PFGE clusters. Finally, a third clone comprised nine B. pyrrocinia isolates belonging to recA RFLP type Se 13. They represented three PFGE clusters and were collected in three CF centers.

Bacterial Typing Techniques↗

PubMed2005

Taxonomy and pathogenesis of the Burkholderia cepacia complex.

Patients with cystic fibrosis (CF) are susceptible to chronic respiratory infection with a number of bacterial pathogens. The Burkholderia cepacia complex bacteria are problematic CF pathogens because (i) they are very resistant to antibiotics, making respiratory infection difficult to treat and eradicate; (ii) infection with these bacteria is associated with high mortality in CF; (iii) they may spread from one CF patient to another, leading to considerable problems for both patients and carers; and (iv) B. cepacia complex bacteria are difficult to identify and nine new species have now been found to constitute isolates originally identified as 'B. cepacia' based on their phenotypic properties. Here we review the changes that have occurred in the taxonomy of the B. cepacia complex and the pathogenic factors these bacteria possess. While the taxonomy of the B. cepacia complex has advanced considerably with the development of accurate methods for their identification, the pathogenic mechanisms employed by these CF pathogens are only just beginning to be explored at the molecular level. Several virulence factors have been defined for B. cenocepacia (the dominant CF pathogen within the complex); however, knowledge of the disease mechanisms employed by other B. cepacia complex species is limited. The recent determination of the complete genome sequences for several of the B. cepacia complex species should greatly enhance our ability to study these problematic CF pathogens.

Burkholderia Infections↗

PubMed2004

Streptococcus minor sp. nov., from faecal samples and tonsils of domestic animals.

Nine isolates, which were obtained from tonsils, anal swabs and faeces of dogs and from tonsils of a cat and a calf, constituted a homogeneous but unidentified taxon after screening with tRNA intergenic length polymorphism analysis and whole-cell protein fingerprinting. 16S rDNA sequence analysis classified representative strains in the genus Streptococcus. Highest sequence similarity (95.9 %) was obtained with Streptococcus ovis. Growth characteristics, biochemical features, DNA-DNA hybridization and DNA G+C contents of selected strains demonstrated that they represent a single, novel streptococcal species. The name Streptococcus minor sp. nov. is proposed for the novel species; the type strain (ON59(T)=LMG 21734(T)=CCUG 47487(T)) was isolated from a dog tonsil.

Animals↗

PubMed2004

Multiplex PCR assay for differentiation of Helicobacter felis, H. bizzozeronii, and H. salomonis.

Helicobacter felis, Helicobacter bizzozeronii, and Helicobacter salomonis are frequently found in the gastric mucous membrane of dogs and cats. These large spiral organisms are phylogenetically highly related to each other. Their fastidious nature makes it difficult to cultivate them in vitro, hampering traditional identification methods. We describe here a multiplex PCR test based on the tRNA intergenic spacers and on the urease gene, combined with capillary electrophoresis, that allows discrimination of these three species. In combination with previously described 16S ribosomal DNA-based primers specific for the nonculturable "Candidatus Helicobacter suis," our procedure was shown to be very useful in determining the species identity of "Helicobacter heilmannii"-like organisms observed in human stomachs and will facilitate research concerning their possible zoonotic importance.

Animals↗

PubMed2004

Recovery of Burkholderia cenocepacia strain PHDC from cystic fibrosis patients in Europe.

BACKGROUND: Burkholderia cenocepacia can cause life threatening respiratory tract infections in patients with cystic fibrosis (CF) and has a significant impact on survival. There is extensive evidence for patient to patient spread and nosocomial transmission of this organism, and several widespread B cenocepacia strains have been described including the transatlantic ET12 clone. A study was performed to compare B cenocepacia isolates recovered from CF patients receiving care in several European countries and strains isolated from other clinical samples and the environment, with reference isolates from the epidemic B cenocepacia strain PHDC which has so far only been recovered from CF patients and soil in the USA. METHODS: A large collection of B cenocepacia isolates, including a large number recovered from CF patients receiving care in several European countries, Canada and the USA, were genotyped by means of randomly amplified polymorphic DNA typing (RAPD) and rep-PCR using the BOX-A1R primer (BOX-PCR). RESULTS: Nineteen Burkholderia cenocepacia isolates cultured from clinical samples in Europe (18 recently recovered from CF patients in France and Italy and one recovered in 1964 from urine in the UK) showed RAPD fingerprinting patterns that were similar to patterns obtained from isolates of B cenocepacia strain PHDC. Subsequent analysis of these isolates using BOX-PCR confirmed that the European isolates and strain PHDC represent the same clone. CONCLUSION: Strain PHDC represents a second transatlantic B cenocepacia clone capable of colonising patients with CF.

Bacterial Typing Techniques↗

PubMed2004

Epidemiology of Burkholderia cepacia complex colonisation in cystic fibrosis patients.

In Belgian cystic fibrosis (CF) clinics, sputum samples are evaluated on selective MAST medium routinely every 3 months. In this study, in 1993 and 1999, isolates were further examined by recA restriction fragment length polymorphism analysis and pulsed-field gel electrophoresis of genomic DNA restricted with SpeI. In 1993, 12 patients were colonised with Burkholderia cepacia complex (Bcc): B. cenocepacia (n=6), B. multivorans (n=3), B. stabilis (n=3). Four patients were colonised with the same B. cenocepacia strain; two with the same B. stabilis strain. After 5 yrs, three B. cenocepacia- and one B. multivorans-colonised patients had died. In 1999, Bcc was isolated in 12 patients: B. multivorans (n=9), B. stabilis (n=1) and B. cenocepacia (n=2). Three patients were colonised by the same B. multivorans strain. Compared to matched controls, the 5 yr outcome was poor; four B. cepacia patients died and none of the control patients died. Lung-function evolution was poor. In conclusion, the rate of colonisation in Belgian cystic fibrosis patients is stable and low. Burkholderia cenocepacia was most prevalent in 1993; Burkholderia multivorans in 1999. The cross-infection rate is low. Three patients had transient colonisation. The impact of Burkholderia cepacia complex on morbidity in the Belgian cystic fibrosis population is high and not limited to Burkholderia cenocepacia.

Adolescent↗

PubMed2004

Arcobacter species in humans.

During an 8-year study period, Arcobacter butzleri was the fourth most common Campylobacter-like organism isolated from 67,599 stool specimens. Our observations suggest that A. butzleri displays microbiologic and clinical features similar to those of Campylobacter jejuni; however, A. butzleri is more frequently associated with a persistent, watery diarrhea.

Adolescent↗

PubMed2003

Fatal outcome of lung transplantation in cystic fibrosis patients due to small-colony variants of the Burkholderia cepacia complex.

The aim of this study was to investigate the possible role of small-colony variant morphotypes of Burkholderia cepacia-like organisms in infectious complications in cystic fibrosis patients following lung transplantation. Respiratory tract specimens from 470 cystic fibrosis patients were screened over a 22-month period for Burkholderia cepacia-like organisms. Nineteen patients were positive for these organisms, eight of whom harboured small-colony-variant morphotypes. Three patients underwent bilateral lung transplantation during the study, two of whom harboured small-colony variants in addition to clonally identical wildtypes of Burkholderia multivorans and Burkholderia cepacia genomovar III prior to lung transplantation. Both patients developed fatal systemic infections post transplantation due to small-colony variants. In vitro testing revealed that small-colony variants exhibited increased serum resistance in comparison to wildtypes. The results of this study indicate that diagnostic efforts should be undertaken to carefully identify small-colony variants of Burkholderia cepacia complex, since they might be an indicator of poor post-transplantation outcome in patients with cystic fibrosis.

Adolescent↗

PubMed2003

Polyclonal outbreak of Burkholderia cepacia complex bacteraemia in haemodialysis patients.

We report a polyclonal outbreak of bacteraemia involving 24 patients at a haemodialysis facility in Recife (Brazil). During the outbreak period (4 June to 11 July, 2001), three Burkholderia cepacia complex strains were isolated from human blood and from various water samples collected at different sites in the haemodialysis unit and from dialysate fluids. Out of 14 patients with positive blood cultures, six were infected by Burkholderia cepacia complex bacteria: three with Burkholderia cepacia genomovar III, two with a first strain of Burkholderia vietnamiensis, and one with the Burkholderia cepacia genomovar III strain and a second B. vietnamiensis strain.

Bacteremia↗

PubMed2001

Development of a new protocol for the isolation and quantification of Arcobacter species from poultry products.

None of the presently available selective supplements for the specific isolation of Arcobacter species allows the growth of Arcobacter butzleri, A. cryaerophilus and A. skirrowii and at the same time fully suppresses the accompanying flora present in poultry and poultry products. Furthermore, little is known about the contamination levels of poultry with Arcobacter species. In this study, a new selective supplement comprising amphotericin B (10 mg/l), cefoperazone (16 mg/l), 5-fluorouracil (100 mg/l), novobiocin (32 mg/l) and trimethoprim (64 mg/l) was developed. With a new isolation procedure, including enrichment in Arcobacter broth with the selective supplement, incubated for 24 to 48 h at 28 degrees C under microaerobic conditions, arcobacters were isolated from 100% (n = 34) of neck skin of laying hens and from 90% (n = 71) of similar samples from broilers. Of the broiler breast meat samples examined (n = 52), 65% were found to be contaminated with these bacteria. In 64% of the samples, A. butzleri was the only Arcobacter species isolated. In 9% of the samples, A. cryaerophilus was the only species present, while 11% of the samples were positive for both species simultaneously. Using direct isolation on the selective agar medium developed in this study, incubated for 24 to 48 h under microaerobic conditions at 28 degrees C. 32 out of 45 broiler carcasses and 6 out of 25 broiler breast meat samples carried a bacterial load of arcobacters of 10(2) to 10(3) cfu/g. The prevalence of Arcobacter in Belgian poultry was found higher than the prevalence of thermophilic Campylobacter species in each of the poultry categories examined. The enrichment procedure and the direct plating method were validated for the isolation of A. skirrowii. For this species, growth performance was less than the other two Arcobacter species and it was not isolated nor detected by m-PCR from the naturally contaminated poultry samples examined. This new protocol provides a fast and reliable method for the isolation of Arcobacter species from poultry and can contribute to more comprehensive epidemiological investigations.

Animals↗

PubMed2001

Infection with Burkholderia cepacia complex genomovars in patients with cystic fibrosis: virulent transmissible strains of genomovar III can replace Burkholderia multivorans.

Infection with Burkholderia cepacia complex in patients with cystic fibrosis (CF) results in highly variable clinical outcomes. The purpose of this study was to determine if there are genomovar-specific disparities in transmission and disease severity. B. cepacia complex was recovered from 62 patients with CF on > or =1 occasions (genomovar III, 46 patients; genomovar II [B. multivorans], 19 patients; genomovar IV [B. stabilis], 1 patient; genomovar V [B. vietnamiensis], 1 patient; and an unclassified B. cepacia complex strain, 1 patient). Patient-to-patient spread was observed with B. cepacia genomovar III, but not with B. multivorans. Genomovar III strains replaced B. multivorans in 6 patients. Genomovar III strains were also associated with a poor clinical course and high mortality. Infection control practices should be designed with knowledge about B. cepacia complex genomovar status; patients infected with transmissible genomovar III strains should not be cohorted with patients infected with B. multivorans and other B. cepacia genomovars.

Adolescent↗

PubMed2001

Lactobacillus alimentarius: a specific spoilage organism in marinated herring.

Spoilage characterised by bulging of lids and gas formation affected various product lots of different marinated herring types. Microbiological analyses resulted in growth on MRS and Rogosa SL agar. Altogether, 206 randomly selected colonies from two unspoiled and ten spoiled samples were characterised using phenotypical key tests and a 16 + 23S rRNA gene-based RFLP identification database. L. alimentarius was found to be the specific spoilage organism in all samples. All isolates obtained from the different product types were of the same clonal type. The slight rise in pH value together with marked gas production suggested a rare lactic acid bacteria spoilage type called 'protein swell'. L. alimentarius has not been previously associated with herring spoilage.

Animals↗

PubMed2001

Burkholderia cepacia complex: distribution of genomovars among isolates from the maize rhizosphere in Italy.

Burkholderia cepacia is a 'complex' in which seven genomic species or genomovars have so far been identified. It appears that all seven B. cepacia genomovars are capable of causing infections in vulnerable persons; in particular, the importance of Burkholderia multivorans (genomovar II) and B. cepacia genomovar III among cystic fibrosis isolates, especially epidemic ones, has been emphasized. In order to acquire a better comprehension of the genomovar composition of environmental populations of B. cepacia, 120 strains were isolated from the rhizosphere of maize plants cultivated in fields located in northern, central and southern Italy. The identification of the different genomovars was accomplished by a combination of molecular polymerase chain reaction (PCR)-based techniques, such as restriction fragment length polymorphism (RFLP) analysis of 16S rDNA (ARDRA), genomovar-specific PCR tests and RFLP analyses based on polymorphisms in the recA gene whole-cell protein electrophoresis. ARDRA analysis allowed us to distinguish between all B. cepacia genomovars except B. cepacia genomovar I, B. cepacia genomovar III and Burkholderia ambifaria (genomovar VII). The latter genomovars were differentiated by means of recA PCR tests and RFLP analyses. Among the rhizospheric isolates of B. cepacia, we found only B. cepacia genomovar I, B. cepacia genomovar III, Burkholderia vietnamiensis (genomovar V) and B. ambifaria. B. cepacia genomovars I and III and B. ambifaria were recovered from all three fields, whereas B. vietnamiensis was detected only in the population isolated from the field located in central Italy. Among strains isolated from northern and southern Italy, the most abundant genomovars were B. ambifaria and B. cepacia genomovar III respectively; in contrast, the population isolated in central Italy showed an even distribution of strains among genomovars. These results indicate that it is not possible to differentiate clinical and environmental strains, or pathogenic and non-pathogenic strains, of the B. cepacia complex simply on the basis of genomovar status, and that the environment may serve as a reservoir for B. cepacia genomovar III infections in vulnerable humans.

Bacterial Typing Techniques↗

PubMed2001

Synthesis of multiple N-acylhomoserine lactones is wide-spread among the members of the Burkholderia cepacia complex.

Seventy strains of the Burkholderia cepacia complex, which currently comprises six genomic species, were tested for their ability to produce N-acylhomoserine lactone (AHL) signal molecules. Using thin layer chromatography in conjunction with a range of AHL biosensors, we show that most strains primarily produce two AHLs, namely N-octanoylhomoserine lactone (C8-HSL) and N-hexanoylhomoserine lactone (C6-HSL). Furthermore, some strains belonging to B. vietnamiensis (genomovar V) produce additional long chain AHL molecules with acyl chains ranging from C10 to C14. For B. vietnamiensis R-921 the structure of the most abundant long chain AHL was confirmed as N-decanoylhomoserine lactone (C10-HSL) by liquid chromatography-mass spectrometry (LC-MS) in combination with total chemical synthesis. Interestingly, a number of strains, most notably all representatives of B. multivorans (genomovar II), did not produce AHLs at least under the growth conditions used in this study. All strains were also screened for the production of extracellular lipase, chitinase, protease, and siderophores. However, no correlation between the AHL production and the synthesis of these exoproducts was apparent. Southern blot analysis showed that all the B. cepacia complex strains investigated, including the AHL-negative strains, possess genes homologous to the C8-HSL synthase cepI and to cepR, which encodes the cognate receptor protein. The nucleotide sequence of the cepI and cepR genes from one representative strain from each of the six genomovars was determined. Furthermore, the cepI genes from the different genomovars were expressed in Escherichia coli and it is demonstrated that all genes encode functional proteins that direct the synthesis of C8-HSL and C6-HSL. Given that cepI from the B. multivorans strain encodes a functional AHL synthase, yet detectable levels of AHLs were not produced by the wild-type, this suggests that additional regulatory functions may be present in members of this genomovar that negatively affect expression of cepI.

4-Butyrolactone↗

PubMed2001

Antimicrobial susceptibilities of Campylobacter strains isolated from food animals in Belgium.

Campylobacter spp. are a frequent cause of diarrhoea in man, originating mostly from poultry. It has been suggested that the veterinary use of antibiotics is largely responsible for resistance in human isolates, particularly to quinolones. During a 6 month period from June to December 1998, 677 Campylobacter isolates were obtained from healthy poultry and pigs. Samples were taken at Belgian slaughterhouses. Species identification was performed by biochemical tests, multiplex PCR and SDS-PAGE of whole-cell proteins. The in vitro susceptibility to six antimicrobial drugs was determined by the agar dilution method. Campylobacter jejuni was found more often in poultry than Campylobacter coli (79% C. jejuni versus 21% C. coli). In pigs the situation was reversed (6 versus 94%). Erythromycin resistance was significantly higher (P < 0.05) in C. coli, particularly in C. coli isolated from pigs (67.2%). Alarmingly high rates of resistance to ciprofloxacin were also noted, particularly for C. coli from broilers (62.1%). The latter indicates that resistance of Campylobacter in humans could derive from animals.

Animals↗

PubMed2001

Genotypic and chemotaxonomic evidence for the reclassification of Pseudomonas woodsii (Smith 1911) Stevens 1925 as Burkholderia andropogonis (Smith 1911) Gillis et al. 1995.

It was reported before that [Pseudomonas] woodsii and Burkholderia andropogonis are phenotypically indistinguishable and probably represent the same taxon, for which the name B. andropogonis has been proposed. In the present study, it was found that [P.] woodsii and B. andropogonis strains were indistinguishable by whole-cell protein electrophoresis and have a highly similar cellular fatty acid composition. A high DNA-DNA binding value of 95% was found between the type strains of both species. In addition, the 16S rDNA sequence of [P.] woodsii strain LMG 2362T was very similar to that of B. andropogonis LMG 2129T (99.0%). The chemotaxonomic and genotypic data confirm that [P.] woodsii and B. andropogonis represent the same species, for which it is proposed to retain the name B. andropogonis.

Bacterial Proteins↗