F. E. Ashton

The structure of the capsular polysaccharide obtained from a new serogroup (L) of Neisseria meningitidis.

A newly isolated serogroup of Neisseria meningitidis (serogroup L), obtained from contacts of a patient with meningococcal meningitis, elaborates a structurally unique, capsular polysaccharide. The polysaccharide contains only 2-acetamido-2-deoxy-D-glucosyl and phosphate constituents in the molar ratio of 3:1, and is composed of the following repeating unit.

The panmictic nature of Neisseria meningitidis serogroup B during a period of endemic disease in Canada

Three hundred and one (301) strains of Neisseria meningitidis serogroup B, isolated from patients with meningococcal disease during the years 1994-1996, were subjected to multilocus enzyme electrophoresis, serotyping, and serosubtyping. Based on the analyses of 14 enzyme loci, 177 electrophoretic types (ETs) were identified. Of these, 136 were represented by single isolates and 41 were represented by multiple isolates (range 2-31). The mean genetic diversity for isolates was 0.444 and for ETs was 0.440. The index of association (I(A)) between loci was 0.530 +/- 0.08 for isolates and 0.256 +/- 0.10 for ETs. Cluster analysis revealed the presence of 39 lineages each represented by a single ET or clusters of ETs. The most common serotypes were 4, 15, and 14 and accounted for 84 (28.0%), 53 (17.6%), and 32 (10.6%) of the isolates, respectively, and were dispersed amongst 46 ETs (1-122), 35 ETs (3-165), and 26 ETs (18-76), respectively. The 109 (36.6%) nontypable (NT) isolates were amongst 74 ETs (6-177). The mean genetic diversity for serotypes 4, 15, and 14 and NT isolates was 0.368, 0.371, 0.343, and 0.442, respectively, and for ETs was 0.363, 0.354, 0.397, and 0.440, respectively. Combinations of serotypes and serosubtypes (number of isolates) that occurred most frequently were 4:P1.14 (17), 14:P1.16 (16), NT:P1.16 (16), 15:P1.16 (13), and NT:P1.13 (13). The majority of group B disease in Canada during 1994-1996 was caused by meningococci of considerable genetic diversity, and reflects a situation of endemic disease. However, the results also indicate that organisms belonging to the ET-5 complex, which has been responsible for outbreaks of group B disease globally for several decades, have been introduced into the country.

A mouse intracerebral infection with Neisseria gonorrhoeae.

An intracerebral challenge of HPB black mice with Neisseria gonorrhoeae is described. In this mode, the mice died from 1 to 6 days after challenge, and T1 organisms were obtained up to the fifth day from brain, liver, kidney, and spleen. Experimental gonococcal vaccines gave good protection against the challenge.

SEROTYPE AND SEROSUBTYPE DISTRIBUTION OF STRAINS OF NEISSERIA MENINGITIDIS ISOLATED IN SOUTH AUSTRALIA AND THE NORTHERN TERRITORY OF AUSTRALIA: 1971-1989

&NA; Strains of meningococci isolated from patients in South Australia (SA) and the Northern Territory (NT) with either bacteremia or meningitis (or both) were serotyped and serosubtyped using monoclonal antibodies in a whole cell ELISA technique. From SA, 144 isolates were examined for the period 1971 through 1989 and from the NT, 38 isolates from 1975 through 1977 and 1983 through 1989 were examined. During the periods of study the principal serogroups were group B in South Australia and group A in the Northern Territory. About 60% of the SA strains were typable and subtypable: the predominant types were 4, 2a, 15 and 14, in that order; the predominant subtypes were P1.2, P1.1 and P1.10, in that order. Of the strains from the NT about 80% were typable, the predominant type was type 4 and all 19 group A strains were identified as type 4, subtype P1.10.

Homocytotropic antibodies (IgE) to Neisseria gonorrhoeae in the rat and a cross-reactivity of heterologous gonococcal strains.

Outbred Wistar rats were immunised with a single intraperitoneal injection of a mixture of 30 mg of A1(OH)3 and 100microng of gonococcal zeolite antigen (ZA). Ten days after immunisation, ZA prepared from T1 and T4 colonies of Neisseria gonorrhoeae strain GC6 (GC6-T1 ZA and GC6-T4 ZA) were able to elicit a reaginic (IgE) response which declined to low levels by 35 days. There was a significant amount of histamine release from the mast cells of actively-sensitised rats on challenge with a specific gonococcal antigen. The antisera heated at a temperature of 56 degrees C for four hours failed to elicit a passive cutaneous anaphylaxis (PCA) reaction, indicating a lack of IgGa antibody. In addition antisera to GC6-T1 ZA gave a positive PCA reaction with GC6-T4 ZA and ZA prepared from T1 colonies of six heterologous gonococcal strains suggesting that these strains of N. gonorrhoeae share common antigenic determinants.

The goat mammary gland as a model infection site for Neisseria gonorrhoeae.

Live and formalin-killed gonococci were instilled into the mammary glands of lactating and nonlactating goats. In lactating goats viable gonococci elicited a limited inflammatory process whereas in non-lactating goats, severe inflammation and swelling appeared and peaked on the 3rd day after instillation and persisted for about 10 days. No viable gonococci were recovered after the first day, but fluorescent antibody staining showed gonococci in the exudate from non-lactating goats up to 7 days after instillation.