- Volume 5, Issue 1, 1972

The theory that culture products of type-12 group A β-haemolytic streptococci may enzymically render IgG autoimmunogenic was investigated with reference to the production of an autologous immune-complex disease in rabbits.

Six groups of 15 animals were used. Autologous serum that had been incubated with a culture of the test streptococcus was centrifuged and freed from bacteria by filtration and then reintroduced into the donor animals in group I. Purified autologous IgG was similarly treated with streptococcal culture and the bacteriafree material was reintroduced into the donor animals in group II. Control animals in groups III and IV were treated similarly to those in groups I and II, except that streptococci were not included in the incubation step. Animals in groups V and VI received untreated autologous serum and untreated autologous IgG respectively.

Fifty per cent, of the animals in groups I and II developed haematuria and proteinuria, and showed glomerular lesions with deposition of host IgG and β1 C on the basement-membranes; no streptococcal antigens could be detected in the kidney. Cultures of the injected preparations yielded no streptococci and results of blood culture and antistreptolysin O determinations were negative for all of the animals. The control animals in groups III-VI showed no abnormalities.

The results of this study support the hypothesis that streptococcal modification of IgG may be related to the development of immune-deposit disease.

A set of 18 bacteriophages was used to type 240 coagulase-negative staphylococci; 75·5 per cent. of the strains were lysed by one or more of the phages, 53 per cent. at RTD and a further 22·5 per cent. only at RTD X 1000. Most of the reactions at RTD could be grouped into seven main patterns. The relative frequency of occurrence in cultures from patients with lesions was somewhat different from that in cultures from nose swabs from healthy persons.

In spite of careful control of technique, variation in phage-typing patterns was observed. The amount of variation appeared to be rather similar to that encountered in phage typing of Staph. aureus .

Serial studies of the nasal flora indicate that some persons carry the same strain for a long time, but that others carry a strain only transitorily. Simultaneous carriage of two distinct strains occurs frequently.

Non-pathogenic perfect yeasts isolated from clinical material are sometimes erroneously identified as species of imperfect genera, such as Candida, because sporulation studies have not been made. Such misidentified isolates may be regarded as pathogens.

The sporulation characteristics of two haploid mating strains of Hansenula anomala and three homothallic strains of Saccharomyces cerevisiae of indifferent sporing quality were examined, by comparing clonally related isolates derived from single vegetative cells, or from ascospores. The haploid strains produced spores only after mating. The media tested were sodium acetate agar, Gorodkowa agar, and V8 agar, and two temperatures of incubation, 23°C and 30°C, were used.

All subcultures of S. cerevisiae spored within 25 days on sodium acetate agar, and sporing occurred more rapidly at 23°C; 67 per cent. spored at 5 days. Subcultures of H. anomala spored within 3 days. This medium is therefore recommended for use in diagnostic laboratories in the investigation of yeast isolates that cannot be identified readily as to genus or species.

Polyacrylamide-gel electrophoretic patterns of the proteins of type strains of atypical mycobacteria and of clinical isolates were compared. Strains identified according to morphological and biochemical characteristics showed patterns identical with those of their respective type strains.

The various type strains could be grouped according to the degree of similarity shown by their protein-gel patterns. This grouping did not always correspond to the standard classification of Runyon.

The photo- and scoto-chromogens appear to be closely related to each other, and to be closer to Myco. tuberculosis than to the other atypical mycobacteria. Within the non-photochromogenic group, Myco. avium and Myco. intracellulare appear to be sufficiently different to justify their separation into different groups. Similarly, the rapid growers seem to form two distinct groups. It is suggested that the current system of classification of Mycobacterium spp. does not accurately reflect genetic relatedness between the different types.

The in-vitro sensitivity of 32 strains of Mycobacterium ulcerans to rifampicin was found to be similar to that of Myco . tuberculosis. A 1-mth course of rifampicin in three different dosage regimens was used to treat experimental Myco. ulcerans infection of mouse foot-pads starting 2 and 5 wk after infection. Each regimen led to clinical improvement, but the disease relapsed 6–8 wk after completion of therapy. Treatment of severe lesions for 10 wk produced apparent cure. A 1-mth course of sulphadoxine plus pyrimethamine or of clofazimine proved ineffective, and combination of these with rifampicin were no more effective than rifampicin alone.

The biological characteristics of eight mycoplasma strains isolated from the nasal cavities or lungs of pigs, and two strains obtained from pigs by other workers, were examined. All strains metabolised arginine but not glucose or urea. They produced characteristic “fried-egg” colonies, but did not grow in medium without serum. Bacterial colonies were not observed after passage of the strains in medium without antibiotics. The colonies did not cause rapid haemolysis of guinea-pig erythrocytes, nor did these cells adhere to the colonies. On the basis of metabolism-inhibition and disk growth-inhibition tests, the strains were closely related to one another. They were different from other mycoplasmas previously isolated from pigs, from various other animal mycoplasmas, and from all other known arginine-utilising mycoplasmas except the recently named M. hyosynoviae and M. suidaniae. It seems that the strains comprise a new mycoplasma species, are present in pigs in various parts of the world, and that the generic name M. hyosynoviae has priority.

After oral dosage of neonatal piglets with Escherichia coli O138:K81(B) extract, antigen was detected within superficial cells of the small intestine after 1 min. and in the spleen after 5 min. The significance of these findings for E. coli disease of young piglets is discussed.

Broth cultures of 27 strains of group-A streptococci and 39 strains of various other Lancefield groups were tested for lymphocyte-transforming activity. All the group-A strains and most of the group-C and group-G strains were strongly mitogenic. The possible significance of the mitogen in streptococcal infection is discussed.

Since 1-hydroxyphenazine was found to inhibit mitochondrial respiration, attempts were made to determine whether this material would affect whole cells. Oxygen uptake by mouse liver L “S” cells, hamster kidney cells (BHK strain C13) and guinea-pig peritoneal macrophages was inhibited by 1-hydroxyphenazine and pyocyanin. In-vivo experiments confirmed that these compounds permeated the cell membrane. Pyocyanin did not inhibit mitochondrial respiration, and the hypothesis was put forward that this compound is acted on by a demethylase to produce the inhibitory 1-hydroxyphenazine and thus cause inhibition of cell respiration.

The efficacy of vaccination against enteric colibacillosis was evaluated in conventionally reared, artificially infected early weaned piglets.

Successful infection with profuse diarrhoea was produced with haemolytic E. coli E145 administered orally to piglets derived from normal sows. Active immunisation of the piglets soon after birth with strain E145 did not protect them from diarrhoea when they were challenged with the same organism. Passive immunisation of piglets with parenterally injected immune serum from a sow vaccinated with strain E145 also failed to protect. On the other hand, no diarrhoea was induced in piglets from sows vaccinated with the challenge organism, although intermittent loose faeces were observed for a relatively short time.

Large numbers of E. coli E145 were excreted 2 days after oral challenge in the faeces of the offspring of normal sows. In contrast, this organism appeared, on the average, 4 days later in the faeces of piglets derived from the vaccinated sows; it was excreted for a shorter time and in smaller numbers.

Circulating antibodies against E. coli E145 were detected by passive cutaneous anaphylaxis before challenge only in piglets derived from vaccinated sows. High serum antibody levels against E145 were detected in all piglets after challenge, irrespective of whether they had actual diarrhoea or not.

A non-haemolytic E. coli strain Mac 111, isolated from a piglet with enteric colibacillosis, failed to induce this disease experimentally.

In adult guinea-pigs, beryllium induces either a skin sensitization or an immunological paralysis.

Skin delayed hypersensitivity results only from the contact of beryllium with the skin. Parenteral administration fails to sensitise, but may induce tolerance. These immune responses are associated with different forms of beryllium: immunogenic (bound to skin constituents) and tolerogenic (freely diffusible). The relative proportion of these fractions depends on the route of administration and on the salt of beryllium. The tolerant state is achieved either by intraperitoneal injection of a very low dose of beryllium (4·78 μg Be per kg intraperitoneally) or by intravenous injection of high toxic doses (400 μg Be per kg); this fits with the model described by Mitchison (1968) for protein antigens.

A strain of Staph. aureus isolated from an infected wound showed firmly linked resistance to penicillin and kanamycin. Variants sensitive to both these antibiotics were produced spontaneously and at a high frequency during storage for a few days at ambient temperature.

Both sensitive and resistant variants produced a highly coloured diffusible pigment.

Electrofocusing resolved six distinct haemolytic components in crude ammonium sulphate-precipitated staphylococcal a-toxin. Four of these had the properties of staphylococcal a-toxin as judged by several criteria and were designated aA (pI = 8·55±0·12); aB (pI = 9·15±0·07); aC (pI = 7·36±0·03); aD (pI = 6·28±0·11); 85·95 per cent. of the recovered activity was found as the aA component. Reversible interconversion of aA and aB was demonstrated and these forms showed similar patterns in disk-gel electrophoresis; each showed a main band having a molecular weight of 36,000 and a second band having a molecular weight of 170,000. In the presence of 6M urea aA yielded a single haemolytic component having a pI of 8·50, and electrophoresis of aA and aB in urea revealed a single main band.

Of the total amount of staphylococcal a-toxin produced in batch cultures, 1 per cent. or less appeared to be cell-associated, indicating rapid release of the toxin into the environment. The level of cell-associated haemolysin reached its maximum at the onset of the stationary phase of growth and decreased thereafter. Cell-associated haemolysin was isolated by the combined use of gel filtration and iso-electric focusing and was characterised by several criteria. Purified material closely resembled the extracellular form of staphylococcal a-toxin.

The authors gratefully acknowledge the photographic assistance of Mr Ian McKee. This work was supported in part by grants from The Royal Society and the Scottish Home and Health Department.

An outbreak of lameness with sudden onset and high morbidity in a flock of 12-wk-old turkeys is reported. The lameness was associated with osteomyelitis caused by Yersinia pseudotuberculosis serotype IA. The condition was reproduced experimentally.

Antigenic studies on variants of Trypanosoma brucei isolated from infected rabbits at different intervals were carried out by agglutination and by opsonic adherence tests with corresponding antisera isolated from the same rabbits. Organisms isolated from infected rabbits 2 and 5 wk after infection were relatively inagglutinable by sera collected at the same time and 3 wk later from the rabbit from which the trypanosomes were derived.

Experiments on adherence of trypanosomes to macrophages in the presence of antibodies indicated the lack of opsonic adherence particularly in the presence of a prozone. These results suggest possible antigenic loss in the presence of antibodies.

The titres of antibodies against three viruses, measles, mumps and herpes simplex, were determined in the cerebrospinal fluid (CSF) and in the serum of 68 patients with various forms of meningitis and encephalitis, as well as in 41 control patients without neurological diseases.

No antibody was detected in CSF from control patients, but 48 per cent. of CSF from patients with neurological involvement had detectable antibody.

The ratio of CSF/serum antibody was highest in subacute sclerosing panencephalitis and bacterial meningitis.

Cytoplasmic inclusions produced in cells infected with RS virus appeared to contain RNA, which was stained by the methyl green-pyronin technique. The staining reaction was largely or totally prevented by pre-treatment with RNase. Hydrolysis with hot trichloro-acetic acid invariably removed all the pyronin-stainable material. These facts suggest that although the majority of the RNA present is probably single-stranded there is a small amount of a double-stranded form present. The inclusion material was also shown to exhibit green fluorescence after staining with acridine orange. Neither standard enzyme digestion procedures nor hot TCA extraction abolished the affinity of the inclusion material for acridine orange although variable results were obtained with higher concentrations (0·02 per cent.) of pepsin. The green fluorescence is probably due to dye-binding by protein. The inclusion material did not stain by the Feulgen, periodic acid-Schiff and oil red O techniques.

A Gram-negative bacillus, provisionally identified as a moraxella, was isolated from an eye infection. The properties of this organism are given and compared with those of similar catalase-negative, oxidase-positive Gram-negative bacilli.

A subculture of this organism has been lodged with the National Collection of Type Cultures, Colindale, London.