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T L Pitt

Publications and source records attributed to T L Pitt.

115 records · Page 7Linked to original sources
PubMed1978

The specificity of agglutination reactions of Pseudomonas aeruginosa with O antisera.

Polyagglutinable (PA) strains of Pseudomonas aeruginosa are agglutinated by more than one of the antisera prepared against antigenically unrelated O serogroups. They form c. 4% of strains--other than isolates from cystic-fibrosis units--submitted to us for typing. We were able to allocate 80% of PA strains to a single O serogroup by agglutination with typing sera that had been absorbed with the polyagglutinable strain SMC-247, or by co-agglutination tests with protein A-containing staphylococci coated with immunoglobulin from unabsorbed sera. Similar results were obtained by precipitation tests with crude bacterial extracts and unabsorbed sera, but these tests were less sensitive and less specific. Evidence is presented that PA antigen is a heat-stable cell constituent distinct from the O antigen. In rabbit antisera, anti-PA antibody is exclusively of the IgM class, but O antibody of both IgM and IgG classes is present.

Agglutination Tests↗
PubMed1977

A comparison of typing methods for Serratia marcescens.

A simple method for the bacteriocine typing of Serratia marcescens without the use of induction was sought. The results of a mutual inhibition experiment with 89 unrelated cultures indicated that a bacteriocine-susceptibility method would give more discrimination between strains than would a bacteriocine-production method. A cross-streaking technique for bacteriocine-susceptibility typing without previous induction was developed, and its performance was compared with that of another susceptibility-typing method in which cell-free lysates of the producer strains were obtained by induction with mitomycin C.Replicate typing of the same collection of cultures by both methods indicated that small variations in pattern were common and that larger variations occurred occasionally. Differences in pattern of less than two strong reactions in the mitomycin-C induction method, and of less than three strong reactions in the cross-streaking method, should therefore not be taken as evidence that strains can be distinguished.Sets of cultures of Ser. marcescens, 178 in total, from a number of supposed incidents of infection in hospitals, were used to evaluate the two bacteriocine-typing methods; all of the cultures were also O serogrouped. Comparison of the typing patterns of members of the same O serogroup from clear-cut incidents of infection confirmed that results of acceptable reliability could be obtained by either bacteriocine-typing method by the application of the appropriate ;difference' rule. When so interpreted, the cross-streaking method appeared to be slightly the more discriminatory.The greatest discrimination between strains was obtained by the use of a ;hierarchical' typing system in which the strains were first O serogrouped, and the cross-streaking method of bacteriocine typing was then used to make subdivisions within O serogroups.

Bacteriocins↗
PubMed1975

An immunological study of the pili of Pseudomonas aeruginosa.

An attempt was made to correlate serological relationships determined by the pili, the flagella and the O-somatic antigens of Pseudomonas aeruginosa, and to make a preliminary assessment of use of the pilus antigen as an epidemiological marker. A method is described for the preparation of antiserum specific for the "normal' PSA pili of P. aeruginosa. A high titre of pilus antibodies was obtained by immunizing rabbits with mutants whose pili had lost their ability to retract into the cell. The "normal' form of the organism, with retractile pili, was poorly agglutinated by high-titre anti-pilus serum, but suspensions of it that had been treated with osmium tetroxide showed greatly increased agglutinability. Antibody labelling for electron microscopy was used to determine the serological relations of pili and of flagella for P. aeruginosa strains belonging to different serological groups as defined by O-somatic antigens. The distribution of pilar and flagellar antigens among strains was not correlated with the O-somatic serotype. A strain of P. aeruginosa carrying a drug-resistance plasmid had fewer "normal' PSA pili than the background strain.

Agglutination Tests↗
PubMed1975

The antibody response to the flagella of Pseudomonas aeruginosa.

Mutants lacking flagella or fimbriae (pili) or both were used for the preparation and absorption of rabbit antisera against the flagella of Pseudomonas aeruginosa. The results of agglutination, immobilisation and complement-fixation tests indicate that the antisera obtained are specific for flagella. The incorporation of nitrate into semi-solid agar for motility and immobilisation tests was found useful for the selection of activity motile cells and for the demonstration of specific antibody to flagella.

Agar↗