E. coli O antisera
For use with boiled culture
O antigens are thermostable lipopolysaccharides (LPS) found in the outer membrane of E. coli. 188 different O antigens are known, designated O1 to O188.
Some O antisera cross-react with antigens from other bacteria, e.g. Shigella and Salmonella, as the O antigens from these species are partly or entirely identical. Before serotyping, it is therefore always important that the identification of E. coli is confirmed, e.g. with biochemical reactions.
The O groups do not correlate with the presence of specific virulence factors. This must be investigated separately.

Product description
O antisera are polyclonal antibodies from rabbits.
In order to minimize cross-reaction problems, the majority of SSI Diagnostica Group E. coli O antisera are supplied as monospecific antisera, i.e. free of known O cross-reactions.
SSI Diagnostica offers O pool antisera and single O antisera supplied as ready-to-use antisera.
In addition, high‑titer single O antisera (if the titer allows) are supplied in 1 mL bottles for a 1:4 dilution by the customer.
How to use
O antisera are used for agglutination of boiled cultures in microtitre plates or Widal tubes. Equal quantities of antiserum and culture are mixed, and the result is read after overnight incubation at 52 °C.
Product range
O pool antisera for complete O-typing | O single antisera, standard titer | O single antisera, high titer
SSI Diagnostica Group offers antisera for identification of all O antigens. As well as single antisera, SSI Diagnostica
Group also offers a pool system: Pool AA-XX.
Pool system AA-XX for full serotyping is constituted so that cross-reacting serotypes are found in the same pool. This minimises the probability of a positive result in two pools.
O pool antisera for complete O-typing
| Article number | Product | Reacts with antigen | No. of tests | Packing |
|---|---|---|---|---|
| 79983 | O pool AA | O1,O2,O50,O53,O74,O107,O117,O175,O187 | 35 | 3 mL vial |
| 79986 | O pool BB | O3,O14,O21,O22,O23,O38,O76,O83,O158 | 35 | 3 mL vial |
| 79987 | O pool CC | O4,O12,O16,O18ab,O18ac,O19,O25,O68,O102,O123 | 35 | 3 mL vial |
| 80006 | O pool DD | O5,O7,O65,O70,O71,O116,O138,O141 | 35 | 3 mL vial |
| 80007 | O pool EE | O6,O8,O9,O20,O57,O60,O93,O101,O188 | 35 | 3 mL vial |
| 80008 | O pool FF | O10,O11,O41,O100,O110,O148,O154,O159,O168,O179 | 35 | 3 mL vial |
| 80009 | O pool GG | O49,O51,O52,O58,O61,O160,O176,O178 | 35 | 3 mL vial |
| 80010 | O pool HH | O13,O17,O44,O62,O66,O73,O77,O106 | 35 | 3 mL vial |
| 80011 | O pool II | O15,O36,O40,O45,O54,O75,O177 | 35 | 3 mL vial |
| 80012 | O pool JJ | O30,O69,O149,O150,O151,O173,O174 | 35 | 3 mL vial |
| 80013 | O pool KK | O24,O27,O29,O35,O56,O81,O169,O186 | 35 | 3 mL vial |
| 80014 | O pool LL | O26,O55,O103,O127,O128abc,O145,O157 | 35 | 3 mL vial |
| 80015 | O pool MM | O28ab,O28ac,O42,O112ab,O112ac,O124,O136,O144 | 35 | 3 mL vial |
| 80016 | O pool NN | O32,O33,O146,O161,O162,O163,O166,O185 | 35 | 3 mL vial |
| 80017 | O pool OO | O34,O46,O85,O130,O134,O140,O167,O171 | 35 | 3 mL vial |
| 80020 | O pool PP | O37,O39,O48,O59,O88,O91,O155,O165,O184 | 35 | 3 mL vial |
| 80021 | O pool QQ | O43,O63,O64,O78,O89,O92,O129 | 35 | 3 mL vial |
| 80022 | O pool RR | O79,O80,O90,O95,O133,O135,O142,O153,O156 | 35 | 3 mL vial |
| 80023 | O pool SS | O82,O87,O96,O105,O120,O137,O170,O183 | 35 | 3 mL vial |
| 80024 | O pool TT | O84,O118,O121,O126,O143,O164,O172 | 35 | 3 mL vial |
| 80025 | O pool UU | O86,O111,O114,O119,O125abc | 35 | 3 mL vial |
| 80026 | O pool WW | O97,O98,O99,O104,O132,O139,O147 | 35 | 3 mL vial |
| 80915 | O pool XX | O108,O109,O113,O115,O131,O152,O180,O181,O182 | 35 | 3 mL vial |
O single antisera, standard titer
| Article number | Product | Incl. in pool | No. of tests | Packing |
|---|---|---|---|---|
| 84997 | O1 | AA | 12 | 1 mL vial |
| 84998 | O2 | AA | 12 | 1 mL vial |
| 84999 | O3 | BB | 12 | 1 mL vial |
| 85000 | O4 | CC | 12 | 1 mL vial |
| 85001 | O5 | DD | 12 | 1 mL vial |
| 85002 | O6 | EE | 12 | 1 mL vial |
| 85003 | O7 | DD | 12 | 1 mL vial |
| 45747 | O8 | EE | 35 | 3 mL vial |
| 45748 | O9 | EE | 35 | 3 mL vial |
| 85006 | O10 | FF | 12 | 1 mL vial |
| 85007 | O11 | FF | 12 | 1 mL vial |
| 85008 | O12 | CC | 12 | 1 mL vial |
| 85009 | O13 | HH | 12 | 1 mL vial |
| 85010 | O14 | BB | 12 | 1 mL vial |
| 85011 | O15 | II | 12 | 1 mL vial |
| 85012 | O16 | CC | 12 | 1 mL vial |
| 85013 | O17 | HH | 12 | 1 mL vial |
| 85014 | O18ab | CC | 12 | 1 mL vial |
| 85015 | O18ac | CC | 12 | 1 mL vial |
| 85016 | O19 | CC | 12 | 1 mL vial |
| 85017 | O20 | EE | 12 | 1 mL vial |
| 85018 | O21 | BB | 12 | 1 mL vial |
| 85019 | O22 | BB | 12 | 1 mL vial |
| 85020 | O23 | BB | 12 | 1 mL vial |
| 85021 | O24 | KK | 12 | 1 mL vial |
| 85022 | O25 | CC | 12 | 1 mL vial |
| 45766 | O26 | LL | 35 | 3 mL vial |
| 85024 | O27 | KK | 12 | 1 mL vial |
| 85025 | O28ab | MM | 12 | 1 mL vial |
| 85026 | O28ac | MM | 12 | 1 mL vial |
| 85027 | O29 | KK | 12 | 1 mL vial |
| 85028 | O30 | JJ | 12 | 1 mL vial |
| 85029 | O32 | NN | 12 | 1 mL vial |
| 85030 | O33 | NN | 12 | 1 mL vial |
| 85031 | O34 | OO | 12 | 1 mL vial |
| 85032 | O35 | KK | 12 | 1 mL vial |
| 85033 | O36 | II | 12 | 1 mL vial |
| 85034 | O37 | PP | 12 | 1 mL vial |
| 85035 | O38 | BB | 12 | 1 mL vial |
| 85036 | O39 | PP | 12 | 1 mL vial |
| 85037 | O40 | II | 12 | 1 mL vial |
| 85038 | O41 | FF | 12 | 1 mL vial |
| 85039 | O42 | MM | 12 | 1 mL vial |
| 85040 | O43 | 12 | 1 mL vial | |
| 85041 | O44 | HH | 12 | 1 mL vial |
| 45785 | O45 | II | 35 | 3 mL vial |
| 85043 | O46 | OO | 12 | 1 mL vial |
| 85044 | O48 | PP | 12 | 1 mL vial |
| 85045 | O49 | GG | 12 | 1 mL vial |
| 85046 | O50 | AA | 12 | 1 mL vial |
| 85047 | O51 | GG | 12 | 1 mL vial |
| 85048 | O52 | GG | 12 | 1 mL vial |
| 85049 | O53 | AA | 12 | 1 mL vial |
| 85050 | O54 | II | 12 | 1 mL vial |
| 85051 | O55 | LL | 12 | 1 mL vial |
| 85052 | O56 | KK | 12 | 1 mL vial |
| 85053 | O57 | EE | 12 | 1 mL vial |
| 85054 | O58 | GG | 12 | 1 mL vial |
| 85055 | O59 | PP | 12 | 1 mL vial |
| 85056 | O60 | EE | 12 | 1 mL vial |
| 85057 | O61 | GG | 12 | 1 mL vial |
| 85058 | O62 | HH | 12 | 1 mL vial |
| 85059 | O63 | 12 | 1 mL vial | |
| 85060 | O64 | 12 | 1 mL vial | |
| 85061 | O65 | DD | 12 | 1 mL vial |
| 85062 | O66 | HH | 12 | 1 mL vial |
| 85063 | O68 | CC | 12 | 1 mL vial |
| 85064 | O69 | JJ | 12 | 1 mL vial |
| 85065 | O70 | DD | 12 | 1 mL vial |
| 85066 | O71 | DD | 12 | 1 mL vial |
| 85067 | O73 | HH | 12 | 1 mL vial |
| 85068 | O74 | AA | 12 | 1 mL vial |
| 85069 | O75 | II | 12 | 1 mL vial |
| 85070 | O76 | BB | 12 | 1 mL vial |
| 85071 | O77 | HH | 12 | 1 mL vial |
| 85072 | O78 | 12 | 1 mL vial | |
| 85073 | O79 | RR | 12 | 1 mL vial |
| 85074 | O80 | RR | 12 | 1 mL vial |
| 85075 | O81 | KK | 12 | 1 mL vial |
| 85076 | O82 | SS | 12 | 1 mL vial |
| 85077 | O83 | BB | 12 | 1 mL vial |
| 85078 | O84 | TT | 12 | 1 mL vial |
| 85079 | O85 | OO | 12 | 1 mL vial |
| 85080 | O86 | UU | 12 | 1 mL vial |
| 85082 | O87 | SS | 12 | 1 mL vial |
| 45825 | O88 | PP | 35 | 3 mL vial |
| 85084 | O89 | 12 | 1 mL vial | |
| 85085 | O90 | RR | 12 | 1 mL vial |
| 85086 | O91 | PP | 12 | 1 mL vial |
| 85087 | O92 | 12 | 1 mL vial | |
| 85088 | O93 | EE | 12 | 1 mL vial |
| 85089 | O95 | RR | 12 | 1 mL vial |
| 85090 | O96 | SS | 12 | 1 mL vial |
| 85091 | O97 | WW | 12 | 1 mL vial |
| 85092 | O98 | WW | 12 | 1 mL vial |
| 85093 | O99 | WW | 12 | 1 mL vial |
| 85094 | O100 | FF | 12 | 1 mL vial |
| 85095 | O101 | EE | 12 | 1 mL vial |
| 85096 | O102 | CC | 12 | 1 mL vial |
| 45839 | O103 | LL | 35 | 3 mL vial |
| 45840 | O104 | WW | 35 | 3 mL vial |
| 85100 | O105 | SS | 12 | 1 mL vial |
| 85102 | O106 | HH | 12 | 1 mL vial |
| 85103 | O107 | AA | 12 | 1 mL vial |
| 85104 | O108 | XX | 12 | 1 mL vial |
| 85105 | O109 | XX | 12 | 1 mL vial |
| 85106 | O110 | FF | 12 | 1 mL vial |
| 45847 | O111 | UU | 35 | 3 mL vial |
| 85108 | O112ab | MM | 12 | 1 mL vial |
| 85109 | O112ac | MM | 12 | 1 mL vial |
| 85110 | O113 | XX | 12 | 1 mL vial |
| 85111 | O114 | UU | 12 | 1 mL vial |
| 85112 | O115 | XX | 12 | 1 mL vial |
| 85113 | O116 | DD | 12 | 1 mL vial |
| 85114 | O117 | AA | 12 | 1 mL vial |
| 85115 | O118 | TT | 12 | 1 mL vial |
| 85116 | O119 | UU | 12 | 1 mL vial |
| 85117 | O120 | SS | 12 | 1 mL vial |
| 45858 | O121 | TT | 35 | 3 mL vial |
| 85119 | O123 | CC | 12 | 1 mL vial |
| 85120 | O124 | MM | 12 | 1 mL vial |
| 85121 | O125abc | UU | 12 | 1 mL vial |
| 85122 | O126 | TT | 12 | 1 mL vial |
| 85123 | O127 | LL | 12 | 1 mL vial |
| 85124 | O128abc | LL | 12 | 1 mL vial |
| 85125 | O129 | 12 | 1 mL vial | |
| 85126 | O130 | OO | 12 | 1 mL vial |
| 85127 | O131 | XX | 12 | 1 mL vial |
| 85128 | O132 | WW | 12 | 1 mL vial |
| 85129 | O133 | RR | 12 | 1 mL vial |
| 85130 | O134 | OO | 12 | 1 mL vial |
| 85131 | O135 | RR | 12 | 1 mL vial |
| 85132 | O136 | MM | 12 | 1 mL vial |
| 85133 | O137 | SS | 12 | 1 mL vial |
| 85134 | O138 | DD | 12 | 1 mL vial |
| 45878 | O139 | WW | 35 | 3 mL vial |
| 85136 | O140 | OO | 12 | 1 mL vial |
| 45880 | O141abc | DD | 35 | 3 mL vial |
| 85138 | O142 | RR | 12 | 1 mL vial |
| 85139 | O143 | TT | 12 | 1 mL vial |
| 85140 | O144 | MM | 12 | 1 mL vial |
| 45884 | O145 | LL | 35 | 3 mL vial |
| 85142 | O146 | NN | 12 | 1 mL vial |
| 85143 | O147 | WW | 12 | 1 mL vial |
| 85144 | O148 | FF | 12 | 1 mL vial |
| 45888 | O149 | JJ | 35 | 3 mL vial |
| 85146 | O150 | JJ | 12 | 1 mL vial |
| 85147 | O151 | JJ | 12 | 1 mL vial |
| 85148 | O152 | XX | 12 | 1 mL vial |
| 85149 | O153 | RR | 12 | 1 mL vial |
| 85150 | O154 | FF | 12 | 1 mL vial |
| 85151 | O155 | PP | 12 | 1 mL vial |
| 85152 | O156 | RR | 12 | 1 mL vial |
| 45896 | O157 | LL | 35 | 3 mL vial |
| 85154 | O158 | BB | 12 | 1 mL vial |
| 85155 | O159 | FF | 12 | 1 mL vial |
| 85156 | O160 | GG | 12 | 1 mL vial |
| 85157 | O161 | NN | 12 | 1 mL vial |
| 85158 | O162 | NN | 12 | 1 mL vial |
| 85159 | O163 | NN | 12 | 1 mL vial |
| 85160 | O164 | TT | 12 | 1 mL vial |
| 85161 | O165 | PP | 12 | 1 mL vial |
| 85162 | O166 | NN | 12 | 1 mL vial |
| 85163 | O167 | OO | 12 | 1 mL vial |
| 85164 | O168 | FF | 12 | 1 mL vial |
| 85165 | O169 | KK | 12 | 1 mL vial |
| 85166 | O170 | SS | 12 | 1 mL vial |
| 85167 | O171 | OO | 12 | 1 mL vial |
| 85168 | O172 | TT | 12 | 1 mL vial |
| 85169 | O173 | JJ | 12 | 1 mL vial |
| 85170 | O174 | JJ | 35 | 1 mL vial |
| 85171 | O175 | AA | 12 | 1 mL vial |
| 85172 | O176 | GG | 12 | 1 mL vial |
| 85173 | O177 | II | 12 | 1 mL vial |
| 85174 | O178 | GG | 12 | 1 mL vial |
| 85175 | O179 | FF | 12 | 1 mL vial |
| 85176 | O180 | XX | 12 | 1 mL vial |
| 85177 | O181 | XX | 12 | 1 mL vial |
| 85178 | O182 | XX | 12 | 1 mL vial |
| 85179 | O183 | SS | 12 | 1 mL vial |
| 85180 | O184 | PP | 12 | 1 mL vial |
| 85181 | O185 | NN | 12 | 1 mL vial |
| 85182 | O186 | KK | 12 | 1 mL vial |
| 84996 | O187 | AA | 12 | 1 mL vial |
| 96274 | O188 | EE | 12 | 1 mL vial |
O single antisera, high titer
The high titer antisera listed in the table below are available off-the-shelf. The other antisera available with standard titer can be produced as high titer on request. Please reach out for further information.
| Article number | Product | Incl. in pool | No. of tests | Packing |
|---|---|---|---|---|
| 81356 | E. coli O1 serum high titer | AA | 40 | 1 mL vial |
| 81359 | E. coli O2 serum high titer | AA | 40 | 1 mL vial |
| 81362 | E. coli O4 serum high titer | CC | 40 | 1 mL vial |
| 81357 | E. coli O6 serum high titer | EE | 40 | 1 mL vial |
| 81361 | E. coli O15 serum high titer | II | 40 | 1 mL vial |
| 81379 | E. coli O16 serum high titer | CC | 40 | 1 mL vial |
| 81365 | E. coli O18ac serum high titer | CC | 40 | 1 mL vial |
| 81369 | E. coli O25 serum high titer | CC | 40 | 1 mL vial |
| 81478 | E. coli O75 serum high titer | KK | 40 | 1 mL vial |
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Discover other E. coli antisera
FAQ:
High titer products should be diluted following the instructions provided on their packaging. The correct dilution rate differs for each product, as it depends on the specific antiserum produced. If you dilute high titer products beyond the recommended amounts, SSI Diagnostica Group cannot ensure that the antiserum will detect all E. coli wild type strains.
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.
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
These bacteria can have a heat-stable capsule; boiling isn’t enough. Autoclave 2 hours at 121 °C to remove the capsule before O serotyping.
Whole bacteria have multiple surface antigens. O antisera are for serotyping on boiled culture as capsules/surface proteins need to be removed by boiling to make the O antigens accessible. O agglutination can take hours to appear—so slide agglutination is inappropriate for O antisera.