Evaluation of CHROMagar Orientation for differentiation and presumptive identification of gram-negative bacilli and Enterococcus species

Merlino, John; Siarakas, Steven; Robertson, Gemma; Funnell, G R; Gottlieb, Thomas; Bradbury, Ross

doi:10.1128/jcm.34.7.1788-1793.1996

Cited by 88 publications

(79 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Faecal samples were streaked on CHROMagar orientation plates [Mast Diagnostics, UK; (Merlino et al, 1996)]. Pink coloured colonies -which were detected in roughly 50% of samples -were assumed to be E. coli (Ewers et al, 2009;Schierack et al, 2009b;Guenther et al, 2010a), and further tested on Gassner and blood agar plates for typical E. coli colony characteristics.…”

Section: Isolation Of E Coli From Faeces and Differentiation By Pfgementioning

confidence: 99%

Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons

Rödiger

Kramer

Frömmel

et al. 2015

Environmental Microbiology

View full text Add to dashboard Cite

We report the population structure and dynamics of one Escherichia coli population of wild mallard ducks in their natural environment over four winter seasons, following the characterization of 100 isolates each consecutive season. Macro-restriction analysis was used to define isolates variously as multi- or 1-year pulsed-field gel electrophoresis (PFGE) types. Isolates were characterized genotypically based on virulence-associated genes (VAGs), phylogenetic markers, and phenotypically based on haemolytic activity, antimicrobial resistance, adhesion to epithelial cells, microcin production, motility and carbohydrate metabolism. Only 12 out of 220 PFGE types were detectable over more than one winter, and classified as multi-year PFGE types. There was a dramatic change of PFGE types within two winter seasons. Nevertheless, the genetic pool (VAGs) and antimicrobial resistance pattern remained remarkably stable. The high diversity and dynamics of this E. coli population were also demonstrated by the occurrence of PFGE subtypes and differences between isolates of one PFGE type (based on VAGs, antimicrobial resistance and adhesion rates). Multi- and 1-year PFGE types differed in antimicrobial resistance, VAGs and adhesion. Other parameters were not prominent colonization factors. In conclusion, the high diversity, dynamics and stable genetic pool of an E. coli population seem to enable their successful colonization of host animal population over time.

show abstract

Section: Isolation Of E Coli From Faeces and Differentiation By Pfgementioning

confidence: 99%

Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons

Rödiger

Kramer

Frömmel

et al. 2015

Environmental Microbiology

View full text Add to dashboard Cite

show abstract

“…Serial dilutions of samples were plated on MacConkey (Oxoid, Hampshire, UK) agar plates and incubated for 18 h at 37°C. Fifty colonies per sample and animal were randomly chosen and plated on GASSNER (Sifin, Berlin, Germany), CHROM agar orientation (Chromagar, Paris, France) (Merlino et al, 1996) and agar plates supplemented with 5% sheep blood except on the first two sampling days where we only plated 20 colonies to all plates. Purple Enterobacteriaceae-like colonies on MacConkey showing typical blue or green colour on GASSNER and violet colour on CHROM agar orientation plates were predefined as E. coli.…”

Section: Isolation and Typing Of E Colimentioning

confidence: 99%

ExPEC‐typical virulence‐associated genes correlate with successful colonization by intestinal E. coli in a small piglet group

Schierack

Walk

Ewers

et al. 2008

Environmental Microbiology

View full text Add to dashboard Cite

Upon studying the transmission of Escherichia coli from a sow to five of her piglets, we observed domination of the coliform flora in piglets by a single E. coli clone, especially after weaning. This haemolytic cloneH1 did not harbour any virulence determinants typical for intestinal pathogenic E. coli isolates from swine but had a virulence gene profile very similar to extraintestinal E. coli (ExPEC), including genes coding for P fimbriae and several iron acquisition systems, besides having an affiliation to the phylogenetic B2 group. Overall, we show that the presence of higher numbers of ExPEC-typical virulence-associated genes (VAGs) in clones correlate with their successful colonization ability in piglets. We conclude that VAGs typical for ExPEC also support intestinal colonization in healthy pigs. Faeces of healthy domestic pigs can harbour high numbers of ExPEC-similar E. coli and are suggested to be a potential risk for the transmission of such bacteria to other hosts.

show abstract

“…Isolates from urine were presumptively identified using chromogenic agar [18] (CHROMagar Orientation, Paris, France). Gram-positive cocci, which appeared as dark blue colonies on chromogenic agar, were reported as 'group D streptococci' if they were susceptible to ampicillin and vancomycin.…”

Section: Identification Of Enterococci In Blood and Urinementioning

confidence: 99%

Difficulties in detection and identification of Enterococcus faecium with low-level inducible resistance to vancomycin, during a hospital outbreak

Pendle

Jelfs

Olma

et al. 2008

Clinical Microbiology and Infection

View full text Add to dashboard Cite

Between June and November 2004, a vancomycin-resistant Enterococcus faecium (VRE) strain was isolated from 13 patients in the haematology/bone marrow transplant unit. There were difficulties in identifying the organism, which had low-level, inducible vancomycin resistance, and standard screening methods did not reveal carriage in patients or their contacts. These technical failures led to spread of VRE and delays in providing appropriate management, which might otherwise have been avoided. Therefore, we reviewed our laboratory methods and compared three identification systems to determine which would best identify this VRE strain. The VITEK 2 (BioMerieux) correctly identified, as E. faecium, only two of 16 isolates, whereas API Rapid ID 32 Strep (BioMerieux) and Phoenix 100 (Becton Dickinson and Co.) correctly identified 13 of 15 and 12 of 13 isolates tested, respectively. Isolates from urine, tested by the CLSI disk diffusion method, were apparently susceptible or of intermediate susceptibility to vancomycin, upon primary testing. VITEK 2 and Phoenix 100 identified all isolates as vancomycin-resistant, although the MICs, measured by Etest, were in the susceptible range for three of 16 isolates. Reducing the vancomycin concentration in screening media substantially increased the sensitivity for detection of VRE. Isolates were characterized as genotype vanB2/3 by PCR and were indistinguishable from each other by pulsed-field gel electrophoresis. VRE with low-level inducible resistance can be missed by routine screening methods. Better identification and screening methods for detection of low-level vancomycin resistance are needed to improve surveillance and prevent transmission of VRE.

show abstract

Evaluation of CHROMagar Orientation for differentiation and presumptive identification of gram-negative bacilli and Enterococcus species

Cited by 88 publications

References 20 publications

Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons

Intestinal Escherichia coli colonization in a mallard duck population over four consecutive winter seasons

ExPEC‐typical virulence‐associated genes correlate with successful colonization by intestinal E. coli in a small piglet group

Difficulties in detection and identification of Enterococcus faecium with low-level inducible resistance to vancomycin, during a hospital outbreak

Contact Info

Product

Resources

About