Occurrence of a Common Type Antigen in Streptococci of Groups D and N

Abstract

SUMMARY: A streptococcus reacting with both group D and group N specific antisera was found to belong to group D ; the reaction with the group N serum was shown by reciprocal absorption tests to be due to a common type antigen. Two group D strains were encountered having this antigen ; both were identified as Streptococcus faecium. The group N strain possessing this same antigen was Streptococcus Zactis. It proved to have a t least one other type antigen, also found in another strain of Strep. Zactis which was not serologically identical. Two antigenic variants were present in cultures of this organism ; one possessed all the type antigens characterizing this strain the other had only one. Attempts to cause further dissociation or reversion were not successful.Streptococci of different Lanceficld groups having common type antigens have been previously reported; Bliss (1 93'7) found a group F type to be serologically identical with a group G type, and Maxted (1949) described four strains of streptococci, one belonging to group B, two to group C and one to group G , each having the R i antigen of group A, type 28. When a streptococcus was encountered which reacted with both a group D and a group N specific antiserum in the precipitin test, using forniamide extracts, it seemed likely that one of the reactions might have been due to a common type antigen. This was found to be so, and the following account is given of a group D and a group N streptococcus having a similar type antigen. Later another group I) strain was found with this same antigen. MATERIALS AND METHODSThe streptococcus strain 748, an extract of which reacted with a group D and a group N serum, was sent to this laboratory by Prof. M. Seelemann, Institut fur Milchhygiene, Kid. It was isolated from the blood of a case of endocarditis. Prof. Seelemann was also kind enough to send samples of his group D and group N sera, and the strains group D 7 5 3

A Serological Classification of Lactobacilli

“…On the other hand, the sharing of antigenic components among different species or even genera of bacteria is not uncommon, e.g. the polysaccharide shared by pneumococcus type I1 and Leuconostoc rnesenteroides (Sugg & Hehre, 1942), the polysaccharide common to pneumococcus type VI and Haemophilus injuenzae type A (Chapman & Osborne, 1942), and a common type antigen shared between group D and group N streptococci (Sharpe, 1952 Harrison & Opal, 1944) work on oral and intestinal strains of lactobacilli, with the use of purified HC1 extracts, apparently indicated type and not group antigens. This was probably due to several causes: (i) as he used quantitative precipitin tests the group antigen, being much weaker than the type, would be diluted out more readily and the group reaction, when present, would only occur in the higher concentrations of antigen and be considered of minor importance; (ii) cultures used for preparing sera had been isolated within the previous 12 months and would have tended to stimulate the production of type rather than group antibodies; (iii) the inoculating suspensions were heated to 65' for 1 hr., and this has been found, at least in some cases, partially to destroy the group antigen.…”

Animal Strains of Group G Streptococci and their Serological Typing

“…Inter-group cross-precipitation was recorded by Bliss (1937), Maxted (1949), Sharpe (1952) and Perry & Briggs (1955). In sorfie cases these cross-reactions may be due to the nucleoprotein antigen common to all streptococci and in others, it is due to the chance possession of the same antigen by individual strains of different Lancefield serological groups.…”

Serological Typing of Strains of Streptococcus faecium and Unclassified Group D Streptococci Isolated from Canned Hams and Pig Intestines

“…Antisera prepared against types 11 and 18 gave no reaction with type 34 extract, and antiserum against type 25 gave no reaction with type 27 extract. Absorption tests, however, showed that relationships did exist ( (Sharpe, 1952) did not react at all with type 27 serum, nor absorb the homologous antibodies from it.…”