E. coli OK O antisera for live culture
OK O antisera are suitable for screening for surface antigens on live cultures, and are particularly suited to test for known EPEC and/or STEC (Shiga toxin-producing E.coli, also known as VTEC: Verocytotoxin-producing E.coli) serotypes.
A positive agglutination test is not indicative of the presence of relevant virulence genes. Positive isolates should therefore be investigated further for virulence factors.
Product description
OK O antisera are polyclonal antisera from rabbits. Serum contains antibodies against several surface antigens . For this reason OK O antisera are intended only for screening and must always be confirmed with O serotyping. OK O antisera are supplied in dropper bottles of 3 mL ready-to-use antiserum, sufficient for at least 150 reactions.
How to use
Place a small drop (approximately 20 μL) of antisera on a glass slide. Transfer culture from two to three colonies to the drop of antiserum and mix well. A positive result will be visible to the unaided eye as agglutination within 10 seconds. Positive slide results need to be confirmed with O antisera for boiled culture.
Product range
OK O pool antisera
| Article number | Product | React with antigen | Number of tests | Packing |
|---|---|---|---|---|
| 44292 | Pool 1 | EPEC/VTEC/ STEC O26, O103, O111, O145, O157 | 150 | 3 mL vial |
| 44293 | Pool 2 | EPEC O55, O119, O125ac, O127, O128ab | 150 | 3 mL vial |
| 77713 | Pool 3 | EPEC O86, O114, O121, O126, O142 | 150 | 3 mL vial |
OK O single antisera
| Article number | Product | Incl. in pool | Number of tests | Packing | |
|---|---|---|---|---|---|
| 44295 | O26 | 1 | 150 | 3 mL vial | |
| 53085 | O45 | 150 | 3 mL vial | ||
| 44296 | O55 | 2 | 150 | 3 mL vial | |
| 44297 | O86 | 3 | 150 | 3 mL vial | |
| 44298 | O103 | 1 | 150 | 3 mL vial | |
| 44299 | O111 | 1 | 150 | 3 mL vial | |
| 44300 | O114 | 3 | 150 | 3 mL vial | |
| 44301 | O119 | 2 | 150 | 3 mL vial | |
| 44302 | O121 | 3 | 150 | 3 mL vial | |
| 44303 | O125ac | 2 | 150 | 3 mL vial | |
| 44304 | O126 | 3 | 150 | 3 mL vial | |
| 44305 | O127 | 2 | 150 | 3 mL vial | |
| 44306 | O128ab | 2 | 150 | 3 mL vial | |
| R* | 72682 | O138 | * | * | |
| R* | 72686 | O139 | * | * | |
| 44307 | O142 | 3 | 150 | 3 mL vial | |
| 44308 | O145 | 1 | 150 | 3 mL vial | |
| R* | 72687 | O149 | * | * | |
| 44309 | O157 | 1 | 150 | 3 mL vial | |
| R* | 44310 | O158 | * | * |
*Please note that the products marked with an R are restricted, indicating the potential need for a forecast, minimum order or extra fee). Please contact us via the contact form if you have an inquiry for one of these products.
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FAQ:
Restricted products (indicated by the R mark in the product tables) have the potential need for a forecast, minimum order, or extra fee. Please contact us via the contact form if you have an inquiry about one of these products.
The strain is likely rough. This can be tested by agglutinating with saline as a negative control. If the negative control is positive, the strain is rough. Rough strains cannot be serotyped. However, a rough strain can be converted to a non-rough strain as follows: Suspend a small amount of colony from a nonselective agar plate in saline (not broth), boil for ≥1 hour, and use the boiled suspension for O serotyping. If unsuccessful, flood a fresh nonselective plate with ethanol, dry it, inoculate the rough colony, then repeat the boil and serotype procedure.
OK O antisera are for screening of whole bacteria. Whole bacteria have multiple surface antigens, increasing the possibility of non-specific reactions. When boiling the bacteria, these surface antigens denature, leaving only the O antigen.
Read positives within the first 10 seconds; after ~20 seconds, sliding can cause nonspecific reactions. Using too much colony mass may show lumps that are not true agglutinations.
E. coli OK O antisera are for live bacteria screening (quick result ~10 seconds) from a non-selective agar plate. O antisera on boiled culture are for full serotyping. The OK O antisera results need to be confirmed with O antisera for a definitive serotyping. .