The Specificity of Agglutination Reactions of Pseudomonas Aeruginosa With O Antisera

Abstract

THE identification of heat-stable somatic antigens is the most widely used method for the serological typing of Pseudomonas aeruginosa. A number of serotyping schemes have been proposed (Habs, 1957;Verder and Evans, 1961 ;Meitert, 1964;Lanyi, 1966-67;Homma et al., 1970) and several numbering systems have been employed for the 0 serotypes or serogroups of P. aeruginosa;we accept the proposal (P. V. Liu, personal communication, 1976) that the numbering system of Habs (1957) should be used for the first 12 serogroups and that higher numbers should be used for additional groups described subsequently by other workers (see also Bergan, 1975).Most of the 0 serogroups of P. aeruginosa are antigenically distinct, and strains can be allocated to them by agglutination tests with rabbit antisera, usually without need to remove cross-reacting antibodies by absorption. However, a minority of strains that are stable in saline suspension are agglutinated by several antisera prepared against apparently unrelated 0 serogroups. These "polyagglutinable" (PA) strains were reported as "non-groupable" by Lanyi (1 966-67) and Homma et al. t 1970). Duncan et al.(1 976) absorbed their typing sera with strain SMC-247 which showed a wide pattern of crossagglutination ; they found that other PA strains gave monospecific reactions with the absorbed sera. We have compared this method with a number of other techniques for the elimination of cross-reactions in the 0 serotyping of PA strains. MATERIALS AND METHODSOrganisms. One representative strain (the type strain) of each of the following serotypes of P. aeruginosa was used for serum production: Habs' types 1-12 (Habs, 1957); the subtypes of types 2 and 5, namely " types " 2b and 5d (Veron, 1961); type 13, the " type I1 " of Sandvik (1960); type 15, the " group 12 " of LBnyi (1966-67); type 16 (strain Psll [Lanyi, 1966-671, related to the " 2-5 complex "); type 17, the " type X " of Meitert (1964). P. acriiginosa strain SMC-247 was a gift from Dr Norma Duncan, Department of Microbiology, University of Ontario, Toronto, Canada. A further 1850 strains of P. aeruginosa were received from various sources for typing in our laboratory.Staphylococcus aureus strain NCTC8530, which is rich in protein A, was used in co-agglutination tests.Media and solutions. Nutrient Broth No. 2 (Oxoid) was used throughout for liquid culture and 1 % (w/v) of agar was added to make nutrient agar. Saline was 0.85 % (w/v) aqueous NaCl, and phenol saline was saline with phenol added to a final concentration of 0.5 % (w/v).Phosphate-buffered saline (PBS ; 0 . 0 0 2~) was prepared by dissolving tablets of PBS reagent

Polyagglutinating and non-typable strains of Pseudomonas aeruginosa in cystic fibrosis

“…However, as anti-7/1 serum did not agglutinate other type strains, this suggests that PA antigen was not exposed on the surface of these strains. The fact that the vaccine strain 7/1 was agglutinated by several 0-typing sera is consistent with the finding of Pitt and Erdman (1978) who showed that some 0-sera contained antibodies to both PA and 0 antigens. It may be, therefore, that although PA antigen is immunogenic in some serotype strains the PA reactions are obtained only with strains lacking 0-type-specific components in their LPS.…”

“…The methods described by Pitt and Erdman (1978) were used for the preparation of 0-antisera, for agglutination tests and for the absorption of antibody from serum.…”

Preparation of agglutinating antisera specific for the flagellar antigens of Pseudomonas aeruginosa

“…Methods for the testing of sera by tray agglutination and absorption of agglutinin were described by Pitt and Erdman (1978). Slide agglutination tests were performed in the standard way.…”

A comparison of flagellar typing and phage typing as means of subdividing the O groups of Pseudomonas aeruginosa

“…0 antisera. The 0-vaccine strains representing the 17 types of the proposed International Antigenic Typing Scheme (IATS) were those described by Pitt and Erdman (1978). In addition, strains 0-6a, 0-6c and 0-6d (see Pitt, 1979) were used for the production of sera for the subdivision of group 0-6.…”

“…0-typing sera were raised in rabbits by the method of Pitt and Erdman (1978) against the strains listed above.…”