Bergeyella (Weeksella) zoohelcum associated with respiratory disease in a cat.
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Animals↗
Biomedical subjects
L A Devriese
Publications and source records attributed to L A Devriese.
Identification and antimicrobial susceptibility of Staphylococcus chromogenes isolates from intramammary infections of dairy cows.
Staphylococcus chromogenes is a highly prevalent species in subclinical mastitis with a well-established impact on somatic cell count. Few data are available on its antimicrobial susceptibility. The objective of this study was three-fold: (1) to evaluate simple identification tests by comparing them with a genomic method; (2) to determine minimal inhibitory concentrations (MICs) of different antibiotics; (3) to search for the presence of important resistance mechanisms and resistance-determining genes.Seventy-three staphylococcal strains, all collected on different dairy farms, were tentatively identified as S. chromogenes based on their lack of hemolysis and their characteristic intermediate DNase activity. The identification of 70 strains was confirmed as S. chromogenes by tRNA intergenic spacer PCR (tRNA PCR). Three strains were identified as S. sciuri, a species that is naturally cloxacillin- and lincomycin-resistant. All 70 S. chromogenes strains were found to be normally susceptible to neomycin, gentamicin, erythromycin, enrofloxacin, and to penicillinase-stable penicillins and cephalosporins, represented in this study by cloxacillin. The latter result was confirmed by the absence of the mecA gene in each of 13 strains in which this gene was searched for. Twenty-seven (38%) strains were penicillinase producers. Three lincomycin-resistant S. chromogenes strains were found to carry the linA gene. It was concluded that S. chromogenes can be identified reliably in routine mastitis bacteriology, and that the only resistance of importance is against penicillinase-susceptible penicillins.
Animals↗
Isolation of Enterococcus cecorum from bone lesions in broiler chickens.
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Animals↗
Identification of a new biotype of Actinomyces hyovaginalis in tissues of pigs during diagnostic bacteriological examination.
Bacterial strains isolated from a large variety of necropsy samples of pigs and previously described as a phenotypical homogeneous group were shown to belong to the species Actinomyces hyovaginalis. This was unexpected because their colonial characteristics, as well as their origins, were very different from those originally reported for the vaginal strains on which the species description of A. hyovaginalis was based. Colonial morphology, as well as fermentation of cellobiose, reactions in hippurate and nitrate and production of beta-glucuronidase, allowed separation of the strains studied here from the vaginal strains. Analysis of tRNA intergenic length polymorphisms (tDNA-PCR), 16S rRNA-gene sequencing and DNA-DNA hybridizations were carried out and led to the proposal of a separate biotype within the species A. hyovaginalis. Since, the strains were isolated from different body sites, this biotype has been designated as the 'general' biotype of A. hyovaginalis, while the strains on which the original species description was based are designated as the 'vaginal' biotype.
Actinomyces↗
Composition of enterococcal and streptococcal flora from pigeon intestines.
AIMS: To identify the streptococcal and enterococcal components of the microflora from pigeon intestines to species level by tDNA-intergenic polymerase chain reaction. METHODS AND RESULTS: Gram-positive coccal strains were isolated from the intestines or faeces of 50 different pigeons, all from different lofts, on Columbia CNA blood agar. Sodium azide-sensitive enterococci were found to constitute the major coccal members of the intestinal flora of pigeons. Forty-two of 69 isolates were identified as Enterococcus columbae (84% of animals tested positive), while E. cecorum was encountered in 28% of all animals (14 isolates). Minor species (less than 10% of pigeons positive) were E. faecalis, E. faecium, E. gallinarum, E. casseliflavus, Streptococcus alactolyticus and Strep. gallolyticus. Contrary to the species description of E. columbae and E. cecorum, some of the strains were found to be motile. Certain other minor differences with the species description of E. columbae are also indicated. CONCLUSIONS: Enterococcus columbae is the major Gram-positive facultatively anaerobic component of the pigeon intestinal flora. Certain phenotypic characteristics differ from the original species description. The potentially pathogenic Strep. gallolyticus is a minor component of the microflora. Enterococcus faecium and E. faecalis are rare in pigeons. SIGNIFICANCE AND IMPACT OF THE STUDY: The enterococcal and streptococcal flora of pigeons is composed of mainly host-specific bacteria. These are not likely to act as zoonotic pathogens nor as carriers of antibiotic resistance determinants possibly spreading to humans.
Animals↗
Differentiation and identification of Enterococcus durans, E. hirae and E. villorum.
AIMS: To compare different tests in the identification of Enterococcus durans, E. hirae and E. villorum strains. These bacteria belong to the E. faecium species group and are phylogenetically closely related, as evidenced by 16S rRNA sequence homologies of over 98.8%. METHODS AND RESULTS: Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis of whole-cell protein, tRNA interpacer polymerase chain reaction (PCR) and arbitrarily-primed (D11344-primed AP) -PCR analysis correctly identified all three species in a collection of strains from very diverse origins. In contrast, biochemical reactions only allowed the unequivocal differentiation of the three species as a group from the other enterococci. Within this group, D-xylose acidification can be used to differentiate E. villorum, but exceptions occur. Strains highly susceptible to clindamycin can be identified as E. durans, but many strains of this species cannot be differentiated from E. hirae and E. villorum due to acquired resistance. CONCLUSIONS: Despite their close relationship, E. durans, E. hirae and E. villorum can be differentiated by genomic methods and by whole-cell protein analysis. SIGNIFICANCE AND IMPACT OF THE STUDY: Only a minority of strains of these three enterococcal species can be identified reliably by the currently available and commonly applied phenotypic tests.
Animals↗
Characterization of yellow-pigmented and motile enterococci isolated from intestines of the garden snail Helix aspersa.
AIMS: Enterococci associated with garden snails (Helix aspersa) were studied in order to obtain reliable species identification and characterization. METHODS AND RESULTS: Twelve yellow-pigmented and motile enterococci, isolated from the intestines of garden snails, were phenotypically close to Enterococcus casseliflavus, but they showed certain unusual biochemical characteristics. tRNA intergenic length polymorphism analysis (tDNA-PCR) divided all strains studied into two groups, in full agreement with biochemical test results. 16S rDNA sequencing, DNA base composition analysis and DNA-DNA hybridization results showed unambiguously that the enterococci studied belonged to the species Ent. casseliflavus. The representative strains of described ecovars were deposited in the Czech Collection of Microorganisms (CCM) as Ent. casseliflavus CCM 4868, 4869, 4870 and 4871. CONCLUSIONS: Enterococcus casseliflavus associated with garden snails can be subdivided into groups. SIGNIFICANCE AND IMPACT OF THE STUDY: Enterococcus casseliflavus differs from other enterococcal species in that it is typically associated with plants, soil, water and invertebrate animals. The different groups that can be found in these widely occurring bacteria are possibly source-specific ecovars, as exemplified by the Ent. casseliflavus inhabiting the intestines of snails.
Animals↗
Prevalence of antimicrobial resistance among pigeon isolates of Streptococcus gallolyticus, Escherichia coli and Salmonella enterica serotype Typhimurium.
Thirty-three Streptococcus gallolyticus, 60 Escherichia coli and 18 Salmonella enterica serotype Typhimurium var. Copenhagen strains isolated from homing pigeons (Columba livia) were tested for susceptibility to the antimicrobials most commonly used to treat pigeons. Minimal inhibitory concentrations were determined using the agar dilution technique. Aminoglycosides (gentamicin and kanamycin), trimethoprim and flumequine were relatively inactive against the streptococci tested. Acquired tetracycline resistance amounted to 85%, and lincomycin and macrolide (erythromycin) resistance to 48 and 45%, respectively. Fluoroquinolone (enrofloxacin) resistance was found in four S. gallolyticus strains. All strains were susceptible to ampicillin. With the E. coli strains, resistance was found to all antibiotics tested. Over one-half of them were resistant to tetracycline and to broad-spectrum penicillins (ampicillin); however, none showed extended spectrum beta-lactamase activity, implying that the cephalosporins (ceftiofur) remained active. Resistance to trimethoprim, aminoglycosides and fluoroquinolone ranked next. In contrast to the S. gallolyticus and E. coli strains, the S. enterica strains were susceptible to all the antimicrobials tested.
Animals↗
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↗
Prevalence and mechanism of resistance against macrolides and lincosamides in Streptococcus suis isolates.
Eighty-seven Streptococcus suis isolates recovered in 1999-2000 from diseased pigs, all from different farms, were screened for resistance against macrolide and lincosamide antibiotics by the disk diffusion and agar dilution test and a PCR assay, amplifying the ermB gene and the mefA/E gene. Seventy-one percent of the isolates showed constitutive resistance to macrolide and lincosamide antibiotics (MLS(B)-phenotype). All these isolates were positive for the ermB gene in the PCR, but negative for the mefA/E gene. For all strains minimum inhibitory concentrations (MIC) against five other antimicrobial agents were determined. All strains were susceptible to penicillin. Ninety-nine percent of the isolates were susceptible to enrofloxacin and tiamulin. Eighty-five percent of the strains were resistant to doxycycline. A 540bp fragment of the ermB genes of eight S. suis strains was sequenced and compared with ermB genes of five S. pneumoniae and five S. pyogenes strains of human origin. A 100% homology was found between these fragments in seven S. suis, one S. pneumoniae and three of the S. pyogenes isolates. This study demonstrates that resistance against macrolides, lincosamides and streptogramin B is widespread in S. suis and mediated by ribosome methylation, encoded by the ermB gene.
Animals↗
Historical aspects of botulinum toxin.
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Botulinum Toxins↗
Evaluation of ribotyping for characterization and identification of Enterococcus haemoperoxidus and Enterococcus moraviensis strains.
Seven Enterococcus moraviensis and 16 Enterococcus haemoperoxidus as well as nine reference cultures of other enterococcal species obtained from the Czech Collection of Microorganisms were characterized using ribotyping with EcoRI and HindIII in the present work. The ribopatterns obtained by both restriction enzymes clearly distinguished all E. moraviensis and E. haemoperoxidus strains from the other enterococci (E. faecalis, E. faecium, E. avium, E. raffinosus, E. pseudoavium, E. malodoratus) and they differentiated both species from each other as well. Although all strains were isolated from different sampling sites, many strains shared the same band patterns. E. moraviensis formed four ribogroups using EcoRI and two ribogroups using HindIII restriction enzyme. E. haemoperoxidus gave six different patterns with EcoRI and five using the HindIII restriction enzyme.
DNA, Bacterial↗
Sequence analysis of a RAPD band differentiating high and low virulence Staphylococcus aureus strains from rabbits.
RAPD typing revealed the presence of a nucleotide band in typical high virulence rabbit Staphylococcus aureus strains which was absent in low virulence strains and in an atypical high virulence strain. The nucleotide sequence of this band was determined. Primers within this sequence were developed and PCR products of eight typical high virulence, one atypical high virulence and nine low virulence rabbit S. aureus strains were sequenced. All low virulence strains and the atypical high virulence strain revealed a constant difference with the typical high virulence strains for nucleotide 377 of the 1055bp sequence. The eight typical high virulence strains possessed a guanine base on this site, while the other strains tested showed an adenine base. These findings support the hypothesis on the clonal origin of typical high virulence rabbit S. aureus strains. After comparison with databases, two open reading frames (ORF) were identified within the sequence, which appeared to encode two structural ribosomal proteins. The single nucleotide mutation does not affect the amino acid sequence of the protein it encodes for.
Animals↗
Secreted antigens as virulence-associated markers in Staphylococcus aureus strains from rabbits.
Western blot analysis was performed from the culture supernatant of 59 rabbit Staphylococcus aureus strains, classified as high and low virulence strains according to their epidemiological behaviour in commercial rabbitries, bio-, phage- and RAPD-type. Fourteen extracellular antigen bands (A-N) were recognised using sera of rabbits immunised with washed, viable high virulence S. aureus bacteria. Eleven of these bands were found in high virulence as well as in low virulence strains. The band A, approximately 78 kDa, was not seen in any of the 27 high virulence strains, except for one strain which was also typical in other aspects, was detected in all, but one of the low virulence strains. The M and N bands with molecular masses of approximately 29 and 27 kDa, respectively, were recognised in all high virulence strains except for the atypical strain, but in none of the low virulence strains. This indicates that the latter two antigens may be virulence-associated markers for S. aureus strains from rabbits.
Animal Diseases↗
Lactobacillus agilis is an important component of the pigeon crop flora.
AIMS: To examine the presence of lactic acid bacteria (LAB: enterococci, streptococci and lactobacilli) in the pigeon crop. METHODS AND RESULTS: The crops of 10 pigeons were sampled and inoculated on agar plates for isolation of streptococci, enterococci and lactobacilli. The isolates were identified using tDNA-PCR. Lactobacillus agilis, a species described in 1981 from municipal sewage, was the dominant component in eight of these pigeon crop sacs. A Lactobacillus species related to L. fermentum and L. mucosae but probably not belonging to one of these species was isolated from five birds. Three pigeons carried Enterococcus cecorum. Minor species found were E. columbae, E. faecalis, E. hirae, L. johnsonii, L. salivarius, and Streptococcus gallolyticus. A description is given of the phenotypic characteristics of the L. agilis pigeon strains. CONCLUSIONS, SIGNIFICANCE AND IMPACT OF THE STUDY: L. agilis is found to be the main component of the LAB flora in the pigeon crop.
Animals↗
The gram-positive tonsillar and nasal flora of piglets before and after weaning.
AIMS: To investigate gram-positive nasal and tonsillar microbial flora of piglets before and after weaning. METHODS AND RESULTS: The nasal and tonsillar gram-positive bacterial flora of 20 non-weaned piglets (2 weeks of age) and 20 weaned piglets (6 weeks of age), obtained from four different piggeries, was quantified by culture and identified by tDNA-PCR. The most widely occurring species from nasal conchae before as well as after weaning in the different piglets investigated were Streptococcus suis and Rothia nasimurium. After weaning a wide variety of Lactobacillus species appeared but in low numbers. In the tonsils, Strep. suis, Strep. dysgalactiae, S. hyicus, S. aureus, Arcanobacterium pyogenes and Actinomyces hyovaginalis were the species isolated from the largest number of pigs before and after weaning. S. aureus and most lactobacilli became more prevalent after weaning. Bacteria not known to be associated with pigs found in the present study included R. nasimurium, Strep. gallolyticus, Pediococcus pentosaceus and some Lactobacillus species. CONCLUSIONS: Over 30 different gram-positive bacterial species may occur in nasal conchae and tonsils of unweaned piglets at 2 weeks of age and of 6-week-old weaned piglets. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated that weaning is associated with changes in prevalence of only a small minority of the highly diversified bacterial flora of the nares and tonsils of pigs.
Animals↗
Enterococcus villorum sp. nov., an enteroadherent bacterium associated with diarrhoea in piglets.
The taxonomic positions of five enteroadherent bacterial pig isolates, showing phenotypic characteristics most similar to those of Enterococcus durans and Enterococcus hirae, were investigated in a polyphasic study that included 16S rDNA sequence analysis, DNA-DNA hybridizations, DNA base-ratio determinations, whole-cell protein fingerprinting, D11344-primed PCR typing and an extensive examination of phenotypic properties. The results demonstrated that the organisms represent a new species in the Enterococcus faecium species group, for which the name Enterococcus villorum sp. nov. is proposed. The type strain is LMG 12287T (= CCM 4887T).
Animals↗
Enterococcus haemoperoxidus sp. nov. and Enterococcus moraviensis sp. nov., isolated from water.
A polyphasic taxonomic approach was used to study atypical enterococci isolated from surface waters. All strains were characterized by physiological and biochemical tests as well as by genotyping. The results of biochemical tests and tRNA intergenic length polymorphism analysis (tDNA-PCR) divided all studied strains uniformly into two groups. Because these groups were clearly separated from all enterococcal species described to date, 16S rDNA sequence analysis, DNA base composition analysis and DNA-DNA hybridization of representative strains were done to elucidate the taxonomic position of the analysed groups. On the basis of the results obtained, the names Enterococcus haemoperoxidus (type strain CCM 4851T = LMG 19487T) and Enterococcus moraviensis (type strain CCM 4856T = LMG 19486T) are proposed for the two hitherto undescribed species. The type strains and reference cultures have been deposited in the Czech Collection of Microorganisms (CCM), Masaryk University, Brno, Czech Republic, and in the BCCM/LMG Culture Collection, Ghent University, Belgium.
Base Composition↗