Previous Article | Next Article 
Journal of Clinical Microbiology, February 2001, p. 544-550, Vol. 39, No. 2
Immunology Research and Development Section,
Oxoid Ltd., Basingstoke, United Kingdom
Received 13 July 2000/Returned for modification 21 September
2000/Accepted 30 October 2000
Many of the commercial slide agglutination tests for
Staphylococcus aureus incorporate antibodies against cell
surface antigens associated with methicillin resistance, including
capsular polysaccharides and an uncharacterized antigen, serotype 18. These tests are more sensitive than the first-generation agglutination
procedures that detected only bound coagulase and protein A, but they
suffer from false-positive reactions with some coagulase-negative
staphylococci. The aim of this study was to elucidate the mechanism for
false-positive agglutination by S. epidermidis in these
tests. A group of methicillin-resistant S. aureus (MRSA)
isolates, including a serotype 18 strain, that were not detectable in
the first-generation tests were found to be of capsular polysaccharide
type 8. All of these isolates were deficient in bound coagulase and/or
protein A, and they possessed a heat-stable, proteinaceous antigen that
was absent from a prototype capsule type 8 strain. Enzyme-linked
immunosorbent assay and agarose gel immunodiffusion experiments
demonstrated that this proteinaceous antigen was also present on both
methicillin-sensitive and methicillin-resistant S. epidermidis clinical isolates. S. epidermidis strains
that gave false-positive agglutination test results had a considerably higher level of this antigen than strains that gave the correct negative result. These findings reveal the importance of the careful selection of MRSA strains for raising anti-capsular type 8 antibodies for use in agglutination tests. Strains devoid of the antigen shared
with S. epidermidis should be used to eliminate potential cross-reactions with this coagulase-negative coccus.
The rapid and accurate diagnosis of
Staphylococcus aureus infection is of vital importance so
that appropriate antimicrobial therapy can be initiated. The
first-generation rapid identification tests for S. aureus
were based on the agglutination of particles coated with plasma to
detect bound coagulase (clumping factor) and protein A (8,
9).
Methicillin-resistant S. aureus (MRSA) strains may fail to
produce agglutination in these tests since they commonly have
undetectable levels of bound coagulase and protein A (10, 18, 32,
33). All of these strains possess capsular polysaccharide
(3, 10), and this may physically mask other cell surface
components (19, 31). Eight serologically distinct types of
capsular polysaccharide were demonstrated by cell agglutination in a
scheme originally described by Karakawa et al. (20).
Capsule types 5 and 8 appear to predominate among clinical isolates of
varied geographical locations (17, 30).
A separate serotyping scheme for S. aureus was established
in France some years earlier (27, 28). In the 1960s a new
serotype of MRSA emerged in French hospitals, and it was designated
serotype 18 on the basis of an uncharacterized cell surface antigen
(26). This serotype became the predominant cause of MRSA
infections in France (4, 14) and more recently in other
European countries (21).
The incorporation of antibodies against capsule types 5 and 8 or
against serotype 18 into several commercial agglutination tests has
improved the sensitivity for MRSA (6, 12, 34). Some of
these tests, however, suffer from false-positive reactions with
coagulase-negative staphylococci (7, 15, 34). Strains of
S. haemolyticus and S. hominis have been reported
to possess type 8 capsular polysaccharide (11, 12). A
strain of S. epidermidis that gave a false-positive reaction
in a commercial agglutination test, however, did not contain either
type 5 or 8 capsules (12).
This study was undertaken to elucidate the mechanism for false-positive
results by S. epidermidis in commercial agglutination tests
for S. aureus that incorporate antibodies against
methicillin resistance-associated antigens. MRSA isolates (including
the original serotype 18 strain) that were undetectable in the
first-generation agglutination tests were examined for the presence of
type 5 or 8 capsules using specific antisera. The effect of
encapsulation on the detectability of cell-bound coagulase and protein
A was determined. The immunological relationship between these MRSA strains and clinical S. epidermidis isolates was
investigated. Two groups of S. epidermidis strains were
selected for this purpose: one that gave false-positive agglutination
test results and one that gave the correct negative result.
Bacteria.
The four MRSA strains selected for this study gave
strong agglutination in three commercially available tests that use
latex sensitized with fibrinogen and antibodies against methicillin resistance-associated antigens, but they failed to agglutinate latex
coated with plasma only. One of these strains (Institute Pasteur,
64002) was the original serotype 18 strain described by Pillet et al.
(26). The other isolates (MRSA1, MRSA2, and MRSA3) were
collected between 1995 and 1999 from hospitals in France, Canada, and
Belgium, respectively. S. aureus reference strains were the
nonencapsulated strain Wood (NCIMB 11852), the capsule type 5 strain
Reynolds (Nabi, Rockville, Md.), and the capsule type 8 strain Becker
(NABI). Twelve S. epidermidis strains were obtained, 1 from
a culture collection and 11 from hospitals in France and the United
Kingdom between 1996 and 1999 (see Table 1). Six of these were
"problematic" strains that gave false-positive reactions in
commercial agglutination tests for S. aureus that incorporate antibodies against methicillin resistance-associated antigens. These isolates did not, however, agglutinate latex coated with plasma only. The other six were "nonproblematic" strains that
gave the correct negative result in these commercial tests. The
isolates were identified by conventional procedures, including API 32 STAPH (bioMerieux, Basingstoke, United Kingdom).
Oxacillin resistance.
Susceptibility to oxacillin was
determined by a standard disc diffusion procedure (23).
Resistant strains were tested for the mecA gene by PCR
(2). Control S. aureus strains for these tests
were ATCC 25923 (sensitive) and NCTC 11939 (resistant).
Coagulase tests.
Bound coagulase was determined using 18- to
24-h brain heart infusion (BHI) broth cultures. Bacteria emulsified in
distilled water were mixed with 10 µl of rabbit plasma (Difco,
Surrey, United Kingdom) on a slide. The slide was rocked, and the
strength of agglutination of the cells after 5 s was recorded.
Overnight BHI broth cultures were tested for free coagulase using a
tube test. One hundred microliters of culture was mixed with 500 µl
of rabbit plasma in a test tube and examined for clot formation after
1, 3, 6, and 24 h at 37°C. The nonencapsulated S. aureus reference strain served as the positive
control for these tests, and S. epidermidis
ATCC 12228 served as the negative control.
Protein A determinations.
Bacteria were grown at 37°C for
24 h on Columbia blood agar (Oxoid Ltd., Basingstoke, United
Kingdom) and harvested into phosphate-buffered saline (PBS; pH 7.3).
These live cell suspensions were standardized by determinations of
optical density at 550 nm. Extracts were also prepared by gently mixing
bacteria at 0.5 g (wet weight)/ml with 25 µg of lysostaphin
(Sigma, Poole, United Kingdom) per ml for 2 h at 37°C. Cell
debris was removed by centrifugation at 25,000 × g for
20 min at 4°C, and supernatants were retained. The protein A contents
of these bacterial preparations were determined by enzyme-linked
immunosorbent assay (ELISA). Since the ELISA signal was proportional to
the concentration of soluble protein A (Sigma) over a narrow range
(30 to 70 ng/ml), it was possible to measure only relative amounts of
protein A in the samples. The levels of protein A in the
bacterial preparations were compared with those of a known high-level
protein A producer, S. aureus Cowan NCTC 8530. The
negative control for this assay was S. epidermidis ATCC 12228.
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.2.544-550.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
A Shared Noncapsular Antigen Is Responsible
for False-Positive Reactions by Staphylococcus epidermidis
in Commercial Agglutination Tests for Staphylococcus
aureus
ABSTRACT
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
INTRODUCTION
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
MATERIALS AND METHODS
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
Preparation of rabbit antisera for serotyping.
Antigens for
immunization were prepared from bacteria grown overnight at 37°C on
Columbia blood agar. Cells were harvested into PBS to give 2 g
(wet weight)/ml, and they were inactivated by one of two methods. The
S. aureus reference capsule type 5 strain and S. epidermidis strain 2213 were heat killed at 80°C for 2 h.
The S. aureus nonencapsulated, capsule type 8, and serotype 18 reference strains were inactivated by incubation with 3%
formaldehyde (Sigma) at room temperature for 18 h. Bacteria were
collected by centrifugation (3,500 × g for 20 min at
4°C), washed twice, and resuspended in PBS. Antisera were prepared as
previously described (20), and they were stored in
aliquots at 
20°C prior to use.
Serotyping ELISA. Formaldehyde-killed bacteria, prepared as described earlier, were diluted in PBS containing 0.1% formaldehyde (Sigma) to an optical density of 0.6 at 550 nm and added to Immulon 2 HB plates at 100 µl/well. Plates were incubated at 4°C overnight, washed twice with PBST, and blocked as described for the protein A assay. Plates were washed twice with PBST, and 100 µl of rabbit antiserum per well (see the previous section), diluted in PBST-BSA, was added. Plates were incubated for 1 h at 37°C and washed three times in PBST. One hundred microliters of protein A-peroxidase (Sigma) per well at 0.25 µg/ml in PBST-BSA was added, and plates were reincubated for 1 h at 37°C. After three washes in PBST, plates were developed using tetramethylbenzidine and the absorbance was recorded at 450 nm against that of a blank well without serum.
Inhibition ELISAs.
Autoclave extracts of Columbia agar-grown
bacteria were prepared by suspending bacteria at 0.5 g (wet
weight)/ml in PBS and autoclaving at 121°C for 60 min. The cell
suspensions were centrifuged at 25,000 × g for 20 min
at 4°C, and the supernatants were stored in aliquots at 20°C. The
ability of these extracts to inhibit the binding of antisera in the
serotyping ELISA was examined. Dilutions of extract and of antiserum
were prepared in PBST-BSA, and 70-µl aliquots of each were mixed for
10 min at room temperature. One hundred microliters of the
serum-extract mixtures per well was added in triplicate to microtiter
plates, and the assay was continued as described above. The mean
absorbance of the test wells was deducted from that of reference wells
without extract, and the difference was expressed as a percentage of
the latter. This percent inhibition of the ELISA signal was plotted
against the reciprocal of the extract dilution.
1-antichymotrypsin (Sigma) at 0.1 mg/ml.
Agarose gel immunodiffusion. Bacterial autoclave extracts were also analyzed by double immunodiffusion in 1.5% agarose (Sigma) in PBS. Extracts were diluted as appropriate in PBS. Antisera were used undiluted or concentrated in Centricon YM-10 devices (Amicon Ltd., Stonehouse, United Kingdom). Thirty-six microliters of extract and the same amount of antiserum were added to separate wells (5 mm in diameter), and gels were placed at 4°C overnight. Gels were washed in several changes of 1 M sodium chloride (1 liter in total) over 2 days and in several changes of distilled water (1 liter in total) for 4 h. Gels were immersed for 5 min in Amido Black stain (5 g of Amido Black [Sigma] per liter in 45% methanol-10% acetic acid-45% distilled water) and destained in a solution containing 45% methanol, 10% acetic acid, and 45% distilled water.
Detection of extracellular slime. Slime production was examined qualitatively using the Congo red agar method (13). Slime producers formed black, dry, and crystalline colonies, whereas non-slime producers formed pink and shiny colonies.
Slime production was measured quantitatively using a modified version of the microplate adherence assay (5). Overnight cultures were diluted 1:50 in 200 µl of BHI broth (Oxoid) supplemented with 0.25% glucose in triplicate wells of a 96-well flat-bottomed tissue culture plate (Life Technologies, Paisley, United Kingdom). After static incubation overnight at 37°C, the amount of growth in each well was measured as an optical density at 540 nm. Wells were emptied, washed three times with PBS and air dried, and adherent growth was stained with 0.1% Safranin (Sigma) for 1 h. Excess stain was removed by rinsing the wells in distilled water, wells were tapped dry, and adherent material was solubilized by incubation with 200 µl of 0.2 M sodium hydroxide for 1 h at 85°C. The absorbance for each strain was remeasured at 540 nm, and these values were corrected for the total amount of growth measured before staining. S. epidermidis strains ATCC 14990, a non-slime producer, ATCC 35983, a moderate-level slime producer, and ATCC 35984, a high-level slime producer, served as controls for both methods.| |
RESULTS |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
Bacterial characterization.
Coagulase tests on the four
MRSA isolates that failed to agglutinate plasma-sensitized latex
revealed that only one strain (MRSA2) had detectable levels of bound
coagulase. The other strains appeared to produce only free coagulase. A
highly sensitive ELISA for protein A was developed (detection limit, 20 ng/ml) in order to measure protein A in these isolates. Live bacterial
suspensions of all four MRSA strains contained considerably less
protein A than did S. aureus Wood, a well-documented
low-level protein A producer, and a reference capsule 5 strain (Fig.
1A). The reference capsule 8 strain had
no detectable cell surface protein A.
|
), Wood (
),
type 5 (
), type 8 (
), MRSA1 (
), MRSA2 (
), MRSA3 (
),
serotype 18 (
), and S. epidermidis ATCC 12228 (
).
|
Serotyping of strains by ELISA. High-titer rabbit sera (giving an ELISA signal at 450 nm of >1.0 for a 1-in-3,000 serum dilution) were obtained against the S. aureus reference strains (nonencapsulated, capsule type 5, capsule type 8, and serotype 18) and against a problematic S. epidermidis strain (2213). The specificities of the latter four sera were improved by absorption with the nonencapsulated S. aureus Wood strain (data not shown).
The anti-S. aureus Wood serum appeared to contain antibodies against species-specific antigens since it bound to all of the S. aureus isolates but failed to bind to the S. epidermidis isolates (Fig. 2). The anti-capsule type 5 serum was specific for the type 5 strain, whereas the anti-capsule type 8 and anti-serotype 18 sera contained antibodies that were cross-reactive for S. aureus type 8 and serotype 18 strains (Fig. 2). The pattern of binding of sera to the other MRSA isolates was similar to the pattern for serotype 18; all of these strains possessed an antigen recognized by anti-capsular type 8 antibodies, although MRSA1 had only a low level of this antigen (Fig. 2).
|
) sera, diluted 1:2,000;
and anti-serotype 18 serum (
), diluted 1:4,000. All determinations
were done in duplicate.
Inhibition ELISAs.
In order to investigate further the
cross-reactions between strains, the ability of autoclave extracts of
the bacteria to inhibit serum binding in the serotyping ELISA was
examined. The binding of anti-type 8 serum to type 8 cells was almost
completely inhibited by extract of this type 8 strain; extracts of
serotype 18 and of the strain MRSA3 also exhibited high levels of
inhibition (Fig. 3A). In contrast,
extracts of the nonencapsulated S. aureus reference strain
and of the 12 S. epidermidis isolates gave no inhibition (Fig. 3A shows the data for a representative problematic S. epidermidis isolate, 2213, and a representative
nonproblematic S. epidermidis isolate, 2214). All of these
levels of inhibition were essentially unchanged when anti-serotype 18 serum replaced anti-type 8 serum in the ELISA and also when the binding
of anti-type 8 serum to serotype 18 was examined (data not shown).
These results confirm that the MRSA isolates possess the type 8 capsular polysaccharide but that S. epidermidis lacks this
capsule.
|
Agarose gel immunodiffusion.
Anti-type 8 serum gave a single
fused line of precipitation in an agarose gel with autoclave extracts
of S. aureus type 8 and the four MRSA strains (Fig.
4A), providing further evidence that all
of these strains possess the type 8 capsule. The serum gave no
precipitation, however, with extract of a problematic S. epidermidis strain, 2213. Anti-serotype 18 serum gave a reaction of identity with extracts of type 8 and the MRSA strains, and it
appeared to recognize an additional antigen in the MRSA extracts, giving a second line of precipitation that was not fully resolved from
the first line (Fig. 4B). Anti-serotype 18 serum recognized a single
identical antigen in extracts of the six problematic S. epidermidis isolates (Fig. 4C). This antigen gave a reaction of
identity with the serotype 18 extract but not with the type 8 preparation (Fig. 4D). Although a low level of binding of the anti-serotype 18 serum to the nonproblematic S. epidermidis
strains was demonstrated by ELISA, this serum failed to give a
precipitin line with extract of a representative nonproblematic
isolate, 2214 (Fig. 4D). This is probably due to the lower sensitivity of agarose gel immunodiffusion. Antiserum raised against a
representative problematic S. epidermidis isolate, 2213, gave a fused precipitin line with extracts of this isolate and the four
MRSA strains (Fig. 4E), confirming that these organisms share a common
antigen. This serum gave no precipitation with extract of the
nonproblematic S. epidermidis isolate, 2214, which
presumably contained a lower level of the shared antigen (Fig. 4E).
|
Detection of extracellular slime.
Since slime production has
been demonstrated for clinical isolates of S. epidermidis
(5, 22) and also more recently for S. aureus
(1) we wanted to determine whether the common antigen on
the MRSA isolates and S. epidermidis was slime associated. The colonial morphology of the 12 S. epidermidis isolates on
Congo red agar (pink and shiny) indicated that none was a slime
producer. The microtiter plate adherence assay for slime appeared to be more sensitive since it detected low levels of slime secretion in some
of these strains (Table 2). Slime
secretion was not, however, exclusive to the problematic isolates.
Furthermore, the MRSA isolates did not produce detectable slime (Table
2), suggesting that the antigen they share with S. epidermidis is not a component of slime.
|
Further analysis of the nature of the antigen common to MRSA and S. epidermidis. Autoclave extracts of the bacteria were treated with sodium periodate to destroy noncapsular polysaccharides and examined by inhibition ELISA. Periodate-treated extract of the nonencapsulated S. aureus strain Wood inhibited the binding of anti-Wood serum to Wood cells at only half the level of inhibition exhibited by untreated extract, serving as a positive control for periodate oxidation. In contrast, periodate oxidation of extracts of S. aureus serotype 18, MRSA3, and the problematic S. epidermidis isolates 2213 and 2216 did not alter their ability to inhibit the binding of anti-serotype 18 serum to serotype 18. Following incubation with trypsin, autoclave extracts of serotype 18, MRSA3, 2213, and 2216 exhibited reduced levels of inhibition of the binding of anti-serotype 18 serum to serotype 18 cells (70, 68, 50, and 51% reductions, respectively). The ability of these extracts to inhibit the binding of anti-type 8 serum to type 8 cells was unaffected by trypsin treatment. Similarly, incubation of serotype 18 and MRSA3 extracts with proteinase K decreased their ability to inhibit the binding of anti-serotype 18 serum to serotype 18 cells by 69 and 60%, respectively, but did not alter their ability to inhibit the binding of anti-type 8 serum to type 8 cells. It appears from these results that the antigen shared between S. aureus serotype 18 and S. epidermidis is a protein.
| |
DISCUSSION |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
The detection of methicillin-resistant S. aureus by rapid agglutination procedures necessitates the incorporation into the test reagents of antibodies against resistance-associated antigens. These include capsular polysaccharide types 5 and 8 and a poorly characterized antigen, serotype 18 (6, 12, 33). Some of these tests suffer from false-positive reactions by coagulase-negative staphylococci (7, 15). This may be due to the production of type 5 and 8 capsular polysaccharides in some species, notably S. haemolyticus and S. hominis (11, 12). The frequency of isolation of coagulase-negative cocci that express these capsular types is 2% in humans (11) and 16% in livestock (29). There are no reports, however, of S. epidermidis possessing type 5 or 8 capsules, and Nelles et al. (24) observed that monoclonal antibodies raised against S. aureus capsule types 5 and 8 failed to react with clinical isolates of S. epidermidis. It follows, therefore, that some other mechanism is responsible for false-positive agglutination by S. epidermidis in tests for MRSA, and this mechanism is described here.
In the present study, four MRSA isolates that failed to agglutinate plasma-coated latex were all of capsular polysaccharide type 8 of the scheme of Karakawa et al. (20). The lack of bound coagulase on all but one of these strains may account for their inability to agglutinate this latex reagent. Furthermore, all of the isolates in common with a prototype capsule 8 strain were deficient in cell surface protein A. In contrast, a prototype capsule 5 strain had significantly higher levels of cell surface protein A. A study by Sutra et al. (31) suggested that type 8 strains produce greater amounts of capsule than type 5 strains. This may account for the more extensive masking of cell surface components such as protein A on type 8 isolates. Lysostaphin digests of capsule 5 and 8 reference strains, serotype 18, and the other MRSA isolates contained relatively higher levels of protein A than were present on intact bacteria, providing evidence for the physical masking of protein A in all of these encapsulated strains.
The MRSA isolates differed from the prototype capsule type 8 strain in that they possessed a second common antigen that was heat stable and protease sensitive. It is unclear whether this proteinaceous antigen is the same antigen that led to the designation of one of the strains, 64002, as the first serotype 18 isolate (26). This serotype 18 antigen is described as a heat-stable cell surface antigen, but the literature does not contain any further clues as to its nature.
None of the 12 S. epidermidis strains that we examined had either type 5 or 8 capsules. Eleven of these isolates, however, possessed a heat-stable protein that was immunologically identical to the proteinaceous material detected in the MRSA strains that failed to agglutinate plasma-sensitized latex. The level of this antigen in S. epidermidis isolates that give false-positive reactions in agglutination tests for MRSA was approximately three times higher than that in strains that give the correct negative result. Since the problematic S. epidermidis isolates included both methicillin-sensitive and methicillin-resistant phenotypes, the antigen that they share with certain MRSA strains may not be truly resistance associated.
To our knowledge this study is the first in which a proteinaceous antigen has been implicated in cross-reactions with antibodies against MRSA-associated antigens. A fibrinogen-binding protein that is related to the bound coagulase (clumping factor) of S. aureus has been reported for several clinical isolates of S. epidermidis (25). Whereas the fibrinogen binding of bound coagulase causes clumping of S. aureus cells, the fibrinogen binding of the S. epidermidis protein does not result in cell clumping. Furthermore, since the problematic S. epidermidis isolates in our study failed to agglutinate latex coated only with plasma, this eliminates the involvement of a fibrinogen-binding protein in the false-positive agglutination results. Hilden et al. (16) described a 230-kDa carbohydrate-containing surface protein of S. aureus that is associated with a negative result in commercial tests designed to detect fibrinogen-binding proteins and/or protein A. This protein does not appear to be the antigen that we have detected in both MRSA and S. epidermidis since it is absent from coagulase-negative cocci (16).
Our findings have revealed the importance of the careful selection of strains for raising anti-capsular type 8 antibodies for use in agglutination tests. Strains devoid of the antigen shared with S. epidermidis should be used in order to eliminate potential cross-reactions with this coagulase-negative coccus.
| |
ACKNOWLEDGMENTS |
|---|
We are grateful to P. A. Lambert (Microbiology and Molecular Biology Research Group, Aston University, Birmingham, United Kingdom) for supplying the control strains for slime determination. We thank N. Woodford (PHLS Central Public Health Laboratory, London, United Kingdom) for mecA testing of the bacteria by PCR.
| |
FOOTNOTES |
|---|
* Corresponding author. Mailing address: Immunology Research and Development Section, Oxoid Ltd., Wade Rd., Basingstoke RG24 8PW, United Kingdom. Phone: 44 (0) 01256 694366. Fax: 44 (0) 01256 463388. E-mail: janet.blake{at}oxoid.com.
| |
REFERENCES |
|---|
|
Top
Abstract
Introduction
Materials and Methods
Results
Discussion
References
|
|---|
| 1. |
Ammendolia, M. G.,
R. Di Rosa,
L. Montanaro,
C. R. Arciola, and L. Baldassarri.
1999.
Slime production and expression of the slime-associated antigen by staphylococcal clinical isolates.
J. Clin. Microbiol.
37:3235-3238 |
| 2. |
Bignardi, G. E.,
N. Woodford,
A. Chapman,
A. P. Johnson, and D. C. E. Speller.
1996.
Detection of the mec-A gene and phenotypic detection of resistance in Staphylococcus aureus isolates with borderline or low-level methicillin resistance.
J. Antimicrob. Chemother.
37:53-63 |
| 3. |
Branger, C.,
P. Goullet,
A. Boutonnier, and J. M. Fournier.
1990.
Correlation between esterase electrophoretic types and capsular polysaccharide types 5 and 8 among methicillin-susceptible and methicillin-resistant strains of Staphylococcus aureus.
J. Clin. Microbiol.
28:150-151 |
| 4. | Chabbert, Y. A., and J. Pillet. 1967. Correlation between methicillin resistance and serotype in Staphylococcus. Nature 213:1137[Medline]. |
| 5. |
Christensen, G. D.,
W. A. Simpson,
J. J. Younger,
L. M. Baddour,
F. F. Barrett,
D. M. Melton, and E. H. Beachey.
1985.
Adherence of coagulase-negative staphylococci to plastic tissue culture plates: a quantitative model for the adherence of staphylococci to medical devices.
J. Clin. Microbiol.
22:996-1006 |
| 6. | Croize, J., P. Gialanella, D. Monnet, J. Okada, A. Orsi, A. Voss, and S. Merlin. 1993. Improved identification of Staphylococcus aureus using a new agglutination test. Results of an international study. APMIS 101:487-491[Medline]. |
| 7. | Cuny, C., B. Pasemann, and W. Witte. 1999. The ability of the Dry Spot Staphytect Plus test, in comparison with other tests, to identify Staphylococcus species, in particular S. aureus. Clin. Microbiol. Infect. 5:114-116[Medline]. |
| 8. |
Essers, L., and K. Radebold.
1980.
Rapid and reliable identification of Staphylococcus aureus by a latex agglutination test.
J. Clin. Microbiol.
12:641-643 |
| 9. | Flandrois, J. P., and G. Carret. 1981. Study of the staphylococcal affinity to fibrinogen by passive hemagglutination: a tool for the Staphylococcus aureus identification. Zentbl. Bakteriol. Hyg. Abt. 1 Orig. A 251:171-176. |
| 10. |
Fournier, J. M.,
A. Boutonnier, and A. Bouvet.
1989.
Staphylococcus aureus strains which are not identified by rapid agglutination methods are of capsular serotype 5.
J. Clin. Microbiol.
27:1372-1374 |
| 11. | Fournier, J. M., A. Bouvet, and A. Boutonnier. February 1990. Process for the preparation of capsular polysaccharides of staphylococci, the polysaccharides obtained, uses of these polysaccharides and strains for carrying out of the process. U.S. patent 4,902,616. |
| 12. |
Fournier, J. M.,
A. Bouvet,
D. Mathieu,
F. Nato,
A. Boutonnier,
R. Gerbal,
P. Brunengo,
C. Saulnier,
N. Sagot,
B. Slizewicz, and J.-C. Mazie.
1993.
New latex reagent using monoclonal antibodies to capsular polysaccharide for reliable identification of both oxacillin-susceptible and oxacillin-resistant Staphylococcus aureus.
J. Clin. Microbiol.
31:1342-1344 |
| 13. |
Freeman, D. J.,
F. R. Falkiner, and C. T. Keane.
1989.
New method for detecting slime production by coagulase negative staphylococci.
J. Clin. Pathol.
42:872-874 |
| 14. | Goullet, P., and H. S. Hieng. 1981. Increase in gentamicin- and tobramycin-resistant Staphylococcus aureus isolates from hospital patients. Nouv. Presse Med. 10:2645-2652[Medline]. |
| 15. | Gupta, H., N. McKinnon, L. Louie, M. Louie, and A. E. Simor. 1998. Comparison of six rapid agglutination tests for the identification of Staphylococcus aureus, including methicillin-resistant strains. Diagn. Microbiol. Infect. Dis. 31:333-336[CrossRef][Medline]. |
| 16. | Hilden, P., K. Savolainen, J. Tyynela, M. Vuento, and P. Kuusela. 1996. Purification and characterisation of a plasmin-sensitive surface protein of Staphylococcus aureus. Eur. J. Biochem. 236:904-910[Medline]. |
| 17. |
Hochkeppel, H. K.,
D. G. Braun,
W. Vischer,
A. Imm,
S. Sutter,
U. Staeubli,
R. Guggenheim,
E. L. Kaplan,
A. Boutonnier, and J. M. Fournier.
1987.
Serotyping and electron microscopy studies of Staphylococcus aureus clinical isolates with monoclonal antibodies to capsular polysaccharide types 5 and 8.
J. Clin. Microbiol.
25:526-530 |
| 18. |
Hsueh, P.-R.,
L.-J. Teng,
P.-C. Yang,
H.-J. Pan,
Y.-C. Chen,
L.-H. Wang,
S.-W. Ho, and K.-T. Luh.
1999.
Dissemination of two methicillin-resistant Staphylococcus aureus clones exhibiting negative Staphylase reactions in intensive care units.
J. Clin. Microbiol.
37:504-509 |
| 19. |
Johne, B.,
J. Jarp, and L. R. Haaheim.
1989.
Staphylococcus aureus exopolysaccharide in vivo demonstrated by immunomagnetic separation and electron microscopy.
J. Clin. Microbiol.
27:1631-1635 |
| 20. |
Karakawa, W. W.,
J. M. Fournier,
W. F. Vann,
R. Arbeit,
R. S. Schneerson, and J. B. Robbins.
1985.
Method for the serological typing of the capsular polysaccharides of Staphylococcus aureus.
J. Clin. Microbiol.
22:445-447 |
| 21. |
Monzon-Moreno, C.,
S. Aubert,
A. Morvan, and N. El Solh.
1991.
Usefulness of three probes in typing isolates of methicillin-resistant Staphylococcus aureus (MRSA).
J. Med. Microbiol.
35:80-88 |
| 22. | Mulder, J. G., and J. E. Degener. 1998. Slime-producing properties of coagulase-negative staphylococci isolated from blood cultures. Clin. Microbiol. Infect. 4:689-694[Medline]. |
| 23. | National Committee for Clinical Laboratory Standards. 1997. Approved standard M2-A6. National Committee for Clinical Laboratory Standards, Wayne, Pa. |
| 24. |
Nelles, M. J.,
C. A. Niswander,
W. W. Karakawa,
W. F. Vann, and R. D. Arbeit.
1985.
Reactivity of type specific monoclonal antibodies with Staphylococcus aureus clinical isolates and purified capsular polysaccharide.
Infect. Immun.
49:14-18 |
| 25. |
Nilsson, M.,
L. Frykberg,
J.-I. Flock,
L. Pei,
M. Lindberg, and B. Guss.
1998.
A fibrinogen-binding protein of Staphylococcus epidermidis.
Infect. Immun.
66:2666-2673 |
| 26. | Pillet, J., B. Orta, F. Corrieras, and M. Perrier. 1966. Characterisation of three new staphylococcal antigens. Differentiation of predominant and secondary agglutinating systems. Ann. Inst. Pasteur (Paris) 110:422-435. |
| 27. | Pillet, J., B. Orta, M. Foucaud, and M. Perrier. 1961. Serological studies on 559 strains of pathogenic staphylococci isolated in France. Ann. Inst. Pasteur (Paris) 100:713-724[Medline]. |
| 28. | Pillet, J., B. Orta, M. Perrier, and F. Corrieras. 1964. A propos of the reference strains used as type-strains I, II and III in serological studies on staphylococci. Ann. Inst. Pasteur (Paris) 106:267-278[Medline]. |
| 29. |
Poutrel, B.,
C. Mendolia,
L. Sutra, and J. M. Fournier.
1990.
Reactivity of coagulase-negative staphylococci isolated from cow and goat milk with monoclonal antibodies to Staphylococcus aureus capsular types 5 and 8.
J. Clin. Microbiol.
28:358-360 |
| 30. |
Sompolinsky, D.,
Z. Samra,
W. W. Karakawa,
W. F. Vann,
R. Schneerson, and Z. Malik.
1985.
Encapsulation and capsular types in isolates of Staphylococcus aureus from different sources and relationship to phage types.
J. Clin. Microbiol.
22:828-834 |
| 31. |
Sutra, L.,
C. Mendolia,
P. Rainard, and B. Poutrel.
1990.
Encapsulation of Staphylococcus aureus isolates from mastitic milk: relationship between capsular polysaccharide types 5 and 8 and colony morphology in serum-soft agar, clumping factor, teichoic acid, and protein A.
J. Clin. Microbiol.
28:447-451 |
| 32. |
Wanger, A. R.,
S. L. Morris,
C. Ericsson,
K. V. Singh, and M. T. Larocco.
1992.
Latex agglutination-negative methicillin resistant Staphylococcus aureus recovered from neonates: epidemiological features and comparison of typing methods.
J. Clin. Microbiol.
30:2583-2588 |
| 33. |
Wichelhaus, T. A.,
S. Kern,
V. Schafer, and V. Brade.
1999.
Rapid detection of epidemic strains of methicillin resistant Staphylococcus aureus.
J. Clin. Microbiol.
37:690-693 |
| 34. | Wichelhaus, T. A., S. Kern, V. Schafer, V. Brade, and K.-P. Hunfeld. 1999. Evaluation of modern agglutination tests for identification of methicillin-susceptible and methicillin-resistant Staphylococcus aureus. Eur. J. Clin. Microbiol. Infect. Dis. 18:756-758[CrossRef][Medline]. |
Journal of Clinical Microbiology, February 2001, p. 544-550, Vol. 39, No. 2
0095-1137/01/$04.00+0 DOI: 10.1128/JCM.39.2.544-550.2001
Copyright © 2001, American Society for Microbiology. All rights reserved.
This article has been cited by other articles:
-
Luczak-Kadlubowska, A., Krzyszton-Russjan, J., Hryniewicz, W.
(2006). Characteristics of Staphylococcus aureus Strains Isolated in Poland in 1996 to 2004 That Were Deficient in Species-Specific Proteins. J. Clin. Microbiol.
44: 4018-4024
[Abstract] [Full Text] -
Brown, D. F. J., Edwards, D. I., Hawkey, P. M., Morrison, D., Ridgway, G. L., Towner, K. J., Wren, M. W. D., on behalf of the Joint Working Party of the Britis,
(2005). Guidelines for the laboratory diagnosis and susceptibility testing of methicillin-resistant Staphylococcus aureus (MRSA). J Antimicrob Chemother
56: 1000-1018
[Abstract] [Full Text] -
Fonsale, N., Bes, M., Verdier, I., Carricajo, A., Ploton, C., Aubert, G., Etienne, J., Vandenesch, F., Freydiere, A. M.
(2004). Specific Identification of Staphylococcus aureus by Staphychrom II, a Rapid Chromogenic Staphylocoagulase Test. J. Clin. Microbiol.
42: 1962-1964
[Abstract] [Full Text]
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»