- Volume 12, Issue 2, 1979

Several substances in urine were found to inhibit the radioimmunoassay of added gonococcal antigens. The supernatants of two-thirds of urine samples from male patients with either gonorrhoea or non-specific urethritis (NSU) were inhibitory. The inhibition caused by many, but not all, samples was reduced or completely abolished by the addition of soybean trypsin inhibitor (STI); STI-sensitive inhibition is thought to be due to proteolytic enzymes, probably from pus cells. Their inhibitory effect was shown to be due to their action on gonoccocal antigens and not on antibodies in the assay system. Some supernatants contained other inhibitors unaffected by STI; some of these were dialysable and others were not.

Sediments from the urine of patients with NSU or gonorrhoea were often strongly inhibitory, but treatment with STI annulled all but very slight inhibition. STI-treated sediments could, therefore, be used in an assay designed to detect gonococcal antigens.

Candida species isolated from the mouths of healthy children and of patients with denture stomatitis included strains of Candida tropicalis that formed germ tubes when incubated in serum.

Twenty-six germ-tube-forming strains of C. albicans and of C. tropicalis were subcultured weekly for 9 wk on blood agar and on Sabouraud’s agar and the ability of each subculture to form germ tubes was measured. All the strains of C. albicans formed almost as many germ tubes after nine weekly subcultures as they did when first isolated. By contrast, although all 26 strains of C. tropicalis formed germ tubes when first isolated, all had lost the ability to do so after six serial weekly subcultures.

Germ-tube formation should not be the sole criterion for the identification of oral C. albicans strains.

The motilities of Proteus long forms during swarming on agar were measured on cells transferred to liquid suspension. During concentric-ring formation on solid medium, when the edge of the swarm was advancing slowly or had stopped, the velocity of long-form motility was low. When the colony was spreading rapidly, long-form velocity was relatively high. This periodic variation in cell velocity, which determines the zones formed during swarming, cannot adequately be explained by negative chemotaxis.

The acquisition of Klebsiella aerogenes by neonates born in hospital has been studied by sero- and klebecin typing. This organism was more commonly carried in the bowel of breast-fed babies than of bottle-fed babies. Only very rarely did babies acquire strains of K. aerogenes from their mothers. K. aerogenes was widely distributed in the ward environment and on the hands of nurses and mothers. Some strains were able to spread on the ward. These results are relevant to the control of K. aerogenes infection in maternity units.

Thirty-six closed abscesses in the subcutis of cats were examined. Of 168 bacterial strains isolated, 121 (72%) were anaerobes and 47 (28%) were facultative anaerobes. Twenty-six abscesses contained mixtures of facultative anaerobes and anaerobes, six contained anaerobes only and four contained facultative anaerobes only. Bacteroides was the genus most commonly isolated (28.6% of all isolates) followed by Fusobacterium (19.0%) and Pasteurella (multocida) (1 3.1%). Peptostreptococcus anaerobius was the most commonly isolated anaerobic species (13.2% of anaerobic isolates and 9.5% of all isolates) and Past. multocida was the most commonly isolated facultative anaerobe (46.8%; 13.1% of all isolates).

Broth cultures of Escherichia coli were examined for mannose-sensitive (MS) haemagglutinin in rocked-tile tests with guinea-pig red cells at ambient temperature, and agar plate cultures were examined for mannose-resistant eluting (MRE) haemagglutinins against 14 species of red cells in tests mixed at 3-5°C in the presence of 0.5% (w/v) D-mannose. Ox, sheep, human, pig, horse, guinea-pig, and fowl red cells were required to detect the various patterns of MRE haemagglutination with the different species of cells.

Of 387 strains in 155 O serogroups, 95 formed both MS and MRE haemagglutinins (MS+/MRE+), 198 formed only MS (MS+/MRE−), 21 only MRE (MS−/MRE+), and 73 neither (MS−/MRE−). Strains of more than one of these types, and MRE+ strains with different cell specificities were found in many of the serogroups. Some strains in 144 O serogroups had MS haemagglutinin and some in 50 an MRE haemagglutinin.

The presence of MS haemagglutinin in a culture was invariably associated with the presence of type-1 fimbriae on the bacteria. All MS+ strains shared a common antigen in their type-1 fimbriae and three groups of these strains possessed also a group-specific fimbrial antigen. The presence of certain kinds of MRE haemagglutinin in over half the MRE+ strains was associated with that of type-MRE fimbriae, but fimbriae were not detected in the other MRE+ strains. The antigens of the MRE haemagglutinins in different strains were heterogeneous and differed from those of the type-1 fimbriae of MS+ strains.

Three series of strains from normal faeces, and from patients with infantile diarrhoea and urinary-tract infections each included a minority possessing neither type of haemagglutinin, but this observation did not preclude a role of the haemagglutinins in colonization or pathogenicity.

A new selective medium containing Pril, xylose, and ampicillin is suggested for the isolation of Aeromonas hydrophila from faeces.

Artificial air pouches in the connective tissue of mice were evaluated as a means of studying Neisseria gonorrhoeae infections. Animals inoculated with type-1 N. gonorrhoeae cells developed an infection characterised by infiltration of polymorphonuclear leucocytes. Viable cocci could be recovered from the air pouches for up to 10 days after infection and intracellular cocci were evident in electronmicrographs within connective-tissue fibroblasts for at least 35 days, indicating that a persistent infection had been established. The mouse air pouch should be of value in the study of gonococcal and other infections.

The rate of reversion from the L-form to the complete bacillus phase of Bacillus licheniformis var. endoparasiticus (BLE) was increased by a factor of c. × 20, by growth in the presence of 1% diaminopimelic acid in a well plate, and c. × 25 with a 1% hog gastric mucin spread on the plate surface. Saturated riboflavin solution and growth products of staphylococci in wells had a lesser effect. The revertants were subsequently stable when isolated in the absence of additive. The rate of reversion from a spheroplast to a diphtheroid phase was not significantly altered by these additives.

These findings are of practical value in studies to distinguish between the BLE sporing bacillus and postulated phases of the organism that include diphtheroid and spheroplast L-forms and debated mycoplasma-like forms.