Evaluation of a fourth-generation latex agglutination test for the identification of Staphylococcus aureus

A latex agglutination kit (AUREUS TEST™) for the rapid identification of Staphylococcus aureus was evaluated in this study. The reagent consists of polystyrene latex particles sensitized with rabbit anti-protein A immunoglobulin G and fibrinogen. Due to the respective binding of bacterial protein A with immunoglobulin G and coagulase with fibrinogen, an agglutination reaction occurs within 1 min when the latex is mixed with a suspension of S. aureus. Of 157 S. aureus isolates (138 from foods) and 110 non-S. aureus isolates (58 species belonging to 19 genera), the sensitivity and specificity of the latex test were 100 and 94.4–100%, respectively. The results were comparable to the conventional coagulase test. Therefore, it is proposed that suspicious colonies of S. aureus on Baird-Parker agar medium be subcultured to tryptic soy agar for overnight incubation. Cultures grown on tryptic soy agar are used for latex agglutination test. The latex agglutination test can be finished within minutes and could be used as an alternative rapid procedure of the coagulase test, which needs several hours or even overnight incubation for completion. In addition, all S. aureus isolates grown on Baird-Parker agar also could be correctly identified by the latex reagent.

Download Full-text

Evaluation of the Methicillin-Resistant Staphylococcus aureus (MRSA)-Screen Latex Agglutination Test for Detection of MRSA of Animal Origin

Journal of Clinical Microbiology ◽

10.1128/jcm.42.6.2780-2782.2004 ◽

2004 ◽

Vol 42 (6) ◽

pp. 2780-2782 ◽

Cited By ~ 23

Author(s):

J. H. Lee ◽

J.-M. Jeong ◽

Y.-H. Park ◽

S.-S. Choi ◽

Y.-H. Kim ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Methicillin Resistant Staphylococcus Aureus ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Animal Origin ◽

Methicillin Resistant

Download Full-text

Efficacy of a Latex Agglutination Test for Rapid Identification of Staphylococcus aureus: Collaborative Study

Journal of AOAC International ◽

10.1093/jaoac/79.3.661 ◽

1996 ◽

Vol 79 (3) ◽

pp. 661-670 ◽

Cited By ~ 3

Author(s):

Tsung C Chang ◽

Su H Huang ◽

H Y Chao ◽

B L Chen ◽

C Chen ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Sensitivity And Specificity ◽

Collaborative Study ◽

False Negative ◽

Pairwise Comparison ◽

Latex Agglutination ◽

Agglutination Test ◽

Latex Agglutination Test ◽

Official Method ◽

Latex Test

Abstract Fifteen laboratories completed a collaborative study comparing the efficacy of a latex agglutination kit (Aureus Test) with that of AOAC Official Method 987.09 (coagulase test for identification of Staphylococcus aureus). Each laboratory analyzed 240 strains of bacteria, including 160 isolates of S. aureus and 80 isolates of other bacteria. Upon receipt of cultures, collaborators subcultured each isolate on both tryptic soy agar (TSA) and Baird-Parker agar medium (BPA) to determine whether the growth medium has any effect on either method. For cultures grown on TSA, the latex test had sensitivity and specificity rates of 99.2 and 97.1 %, respectively, whereas the coagulase test had respective rates of 98.4 and 92.5%. For cultures able to grow on BPA, the latex test had sensitivity and specificity rates of 99.2 and 96.6%, respectively, while the coagulase test had respective rates of 98.3 and 91.3%. By using the McNemar pairwise comparison test of the 2 methods, the falsepositive and false-negative rates of the latex test were significantly lower (p < 0.01) than those of the coagulase test for strains grown either on TSA or BPA. The latex agglutination test for identification of S. aureus isolated from foods has been adopted by AOAC INTERNATIONAL.

Download Full-text