- Volume 1, Issue 2, 1968

The technical details of four tests recommended for the diagnosis of acute and chronic brucellosis are described. They are the standard agglutination, mercaptoethanol, anti-human globulin and complement fixation tests. These tests may be used to differentiate between IgM and IgG antibodies, the relative amounts of which give an indication of the current stage of the disease. A diagnosis of brucellosis can be made with certainty only if IgG is present. However, it must be remembered that the presence of IgG antibody may not necessarily signify active infection, but may be due to constant exposure to brucellae, as with veterinary surgeons.

Six strains of Ps. stutzeri, recently isolated from pathological material obtained from human sources in this country, as well as two strains from the National Collection of Type Cultures, were compared with five strains of Ps. pseudomallei.

The two species could readily be differentiated by means of the aerobic nitrate reduction test : Ps. stutzeri reduces nitrate rapidly and completely with the production of gas, whereas Ps. pseudomallei reduces nitrate only to nitrite. Ps. stutzeri has a single polar flagellum, Ps. pseudomallei has several polar flagella. Ps. pseudomallei has heat-stable alkaline phosphatases and gives positive results in the tests for gelatin liquefaction, arginine desimidase, intracellular accumulation of poly-β-hydroxybutyrate, casein hydrolysis, KCN tolerance and opalescence on LV agar. Ps. stutzeri strains were negative in all these respects.

At present it is not possible to say for certain whether Ps. stutzeri found in pathological material represents a secondary invader in a debilitated host or should be regarded as a contaminant.

Simultaneous oral challenge of calves with S. dublin, S. typhimurium and S. choleraesuis produced a severe disease essentially similar to that produced by giving one of the serotypes alone. In general, organisms of the three serotypes were similarly distributed throughout the contents of the alimentary tract and the tissues. This applied even when the challenge dose of each of the three serotypes was reduced to 104.

The distribution of organisms was different in rabbits, mice and fowls simultaneously challenged with these three serotypes.

A case of cutaneous human infection with a species of the achloric algal genus Prototheca is described. The infection occurred in a woman who had diabetes mellitus and widespread metastatic carcinoma from the breast, and whose therapy included corticosteroids, cytotoxic drugs, antibacterial agents and antibiotics. The organism was cultured from the lesions and identified in them with the light and electron microscopes on two separate occasions. It was non-pathogenic on inoculation in guinea-pigs, mice, rats and rabbits. The case is viewed in the light of the concept of microbial opportunism, and it is postulated that the alga requires a distinct, but as yet undefined, alteration in the host resistance before it is able to act as a pathogen.

Twenty-two samples of serum obtained from patients suffering from infectious or serum hepatitis, 12 samples from blood donors known to have caused hepatitis in recipients and one sample of serum that had caused hepatitis in human volunteers were examined for their capacity to induce interfering substances, and thus, indirectly, for the presence of infectious virus.

No virus-inhibitory activity was detected with any of the sera examined.

A tracheostomy following aortic valve homograft replacement was infected with organisms of a Candida species. The infection spread to one of many thrombo-embolic lesions in the lung and became fungaemic with production of widespread microscopic foci. Infection of the homograft valve was minimal and secondary to the fungaemia.

We should like to thank Mr L. L. Bromley, who looked after the patient, Dr R. R. Davies for help with the identification of the fungus, Professor R. E. O. Williams for helpful suggestions and Mr A. Beasley for the staining and photographing of the specimens.

The one hundred and seventeenth meeting of the Society was held in the University of Bristol on Thursday, Friday and Saturday, 11th, 12th and 13th July 1968.