Essum AB

[+] GBS infections in infants [1]

The GBS Serotyping Test

The GBS Serotyping Test may be used for serotype classification of colonizing and invasive strains for epidemiological purposes. The kit recognizes the 9 serotypes (polysaccharide antigens): Ia, Ib, II, III, IV, V, VI, VII and VIII.

The test is based on the principle of co-agglutination. IgG binding particles are coated with rabbit antibodies specific to the polysaccharide type antigens of GBS. When this suspension is mixed with GBS from a culture plate agglutination occurs with the suspension containing the corresponding antibody.

The standard kit contains six dropper bottles for each serotype (Ia, Ib, II, III, IV, and V) each containing 1,5 ml of suspension. Reagents for the less frequently occurring serotypes (VI, VII, VIII) can be purchased separately. A dropper bottle with a control antigen (serotype III) is also provided. The kit’s expiry time is 2 years and all reagents should be stored at +6ºC.

Assay procedure

The reagent bottles should be agitated before use to resuspend contents.

• Place 40µl (1 drop) of reagent from each bottle in the agglutination site on the test plate.
• Use a conventional 10µl loop to pick some fresh colonies from the plate where the bacteria have been isolated, and transfer adjacent to the test plate.
• Place the loop in the drop and return this small volume to mix with bacterial material. Then mix and spread with the rest of the reagent with in the agglutination site.
• Using a fresh loop, repeat the procedure above for each serotype and agglutination site on the test plate.
• Agitate the test plate gently for 1 minute. Read the agglutination pattern while agitating.

Step 1, 2, 3
If the tested GBS strain belongs to one of the 9 polysaccharide serotypes, a visible agglutination should appear after 1 minute (often earlier). Infrequently, some GBS-strains may give a non-specific, weak agglutination with more than one reagent. The result of the test may then be more clear-cut if a dense suspension of washed GBS, harvested from an over night culture, is used. If all tests are consistently negative it is possible to use the positive control to check the procedure. If the test still is negative the polysaccharide capsule of the investigated isolate may be too scarce, absent, or belong to a serotype other than Ia-VIII.

[Download PDF]

We have distributors in Ireland, Spain, Kuwait, Australia and Taiwan. Please contact us and we will direct you to them. It is possible to order the GBS Serotyping Test direct from Essum if there is no distributor in you country. You can make you order by email, telefax or on our website. If you have any questions do not hesitate to contact us.

Articles Involving Our GBS-Kit

Berg S, Kasvi S, Trollfors B, Pilichowska-Paszkiet J, Fattom A, Tessin I, Lagergard T. Serotypes and clinical manifestations of group B streptococcal infections in western Sweden. Clin Microbiol Infect. 2000 Jan;6(1):9-13.

E. Persson, S. Berg, B. Trollfors, P. Larsson, E. Ek, E. Backhaus, B. E. B. Claesson, L. Jonsson, G. Rådberg, T. Ripa and S. Johansson. Serotypes and clinical manifestations of invasive group B streptococcal infections in western Sweden 1998-2001. Clin Microbiol Infect. 2004 Sep;10(9):791

[1] Baker C J., Edwards M S. Group B streptococcal infections. In: Remington J, Klein JO, (eds). lnfectious Diseases of the Fetus and Newborn lnfant. 5:th ed. pp. 1091-1156. W B Saunders, Philadelphia 2001. ISBN 0-7216-7976-5.

[-] GBS infections in infants [1]

GBS is a major cause of life-threatening neonatal infection. The early onset disease is caused by vertical transmission of bacteria from mother to infant during labor with the predominanat route of infection through the respiratory tract of the infant. 10-30% of pregnant women are colonized with GBS in the vagina. The natural reservoir of GBS is the gastrointestinal tract, and this is probably the source of vaginal colonization. Today there are nine known serotypes of GBS; Ia, Ib and II-VIII.

Early onset GBS infection occurs within 7 days after birth and accounts for a majority of cases. The symptoms often appear within 24 hours, usually with initial signs of respiratory distress with a rapid deterioration and septicemia.

Late onset GBS disease occurs 7 days to 3 months after birth, with serotype III as the predominant agent. The source of this disease is less well understood but contact transmission may occur from parents or care giving staff. Late onset GBS infection is often complicated by meningitis.

The GBS Serotyping Test

The GBS Serotyping Test may be used for serotype classification of colonizing and invasive strains for epidemiological purposes. The kit recognizes the 9 serotypes (polysaccharide antigens): Ia, Ib, II, III, IV, V, VI, VII and VIII.

The test is based on the principle of co-agglutination. IgG binding particles are coated with rabbit antibodies specific to the polysaccharide type antigens of GBS. When this suspension is mixed with GBS from a culture plate agglutination occurs with the suspension containing the corresponding antibody.

The standard kit contains six dropper bottles for each serotype (Ia, Ib, II, III, IV, and V) each containing 1,5 ml of suspension. Reagents for the less frequently occurring serotypes (VI, VII, VIII) can be purchased separately. A dropper bottle with a control antigen (serotype III) is also provided. The kit’s expiry time is 2 years and all reagents should be stored at +6ºC.

Assay procedure

The reagent bottles should be agitated before use to resuspend contents.

• Place 40µl (1 drop) of reagent from each bottle in the agglutination site on the test plate.
• Use a conventional 10µl loop to pick some fresh colonies from the plate where the bacteria have been isolated, and transfer adjacent to the test plate.
• Place the loop in the drop and return this small volume to mix with bacterial material. Then mix and spread with the rest of the reagent with in the agglutination site.
• Using a fresh loop, repeat the procedure above for each serotype and agglutination site on the test plate.
• Agitate the test plate gently for 1 minute. Read the agglutination pattern while agitating.

Step 1, 2, 3
If the tested GBS strain belongs to one of the 9 polysaccharide serotypes, a visible agglutination should appear after 1 minute (often earlier). Infrequently, some GBS-strains may give a non-specific, weak agglutination with more than one reagent. The result of the test may then be more clear-cut if a dense suspension of washed GBS, harvested from an over night culture, is used. If all tests are consistently negative it is possible to use the positive control to check the procedure. If the test still is negative the polysaccharide capsule of the investigated isolate may be too scarce, absent, or belong to a serotype other than Ia-VIII.

[Download PDF]

We have distributors in Ireland, Spain, Kuwait, Australia and Taiwan. Please contact us and we will direct you to them. It is possible to order the GBS Serotyping Test direct from Essum if there is no distributor in you country. You can make you order by email, telefax or on our website. If you have any questions do not hesitate to contact us.

Articles Involving Our GBS-Kit

Berg S, Kasvi S, Trollfors B, Pilichowska-Paszkiet J, Fattom A, Tessin I, Lagergard T. Serotypes and clinical manifestations of group B streptococcal infections in western Sweden. Clin Microbiol Infect. 2000 Jan;6(1):9-13.

E. Persson, S. Berg, B. Trollfors, P. Larsson, E. Ek, E. Backhaus, B. E. B. Claesson, L. Jonsson, G. Rådberg, T. Ripa and S. Johansson. Serotypes and clinical manifestations of invasive group B streptococcal infections in western Sweden 1998-2001. Clin Microbiol Infect. 2004 Sep;10(9):791

[1] Baker C J., Edwards M S. Group B streptococcal infections. In: Remington J, Klein JO, (eds). lnfectious Diseases of the Fetus and Newborn lnfant. 5:th ed. pp. 1091-1156. W B Saunders, Philadelphia 2001. ISBN 0-7216-7976-5.

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Group B Streptococcus [GBS] Serotyping Test

The Essum GBS test is intended for the serotyping of clinical isolates of GBS from culture plates where the organism has been isolated.