- Volume 1, Issue 1, 1968

A fatal case of liver abscesses caused by Klebsiella aerogenes serotype 7 in a 5-yr-old female child is described. The occurrence of this type of infection in a previously healthy patient is unusual and factors that confused the diagnosis in the present case are discussed.

Protective immunity against intraperitoneal challenge with Trypanosoma brucei of homologous antigenic type was produced in mice by the induction of infection and its cure with a drug. It was also produced by single doses of a variety of vaccines, including killed organisms, released antigens and formalinised whole infected blood or plasma administered in the form of crude, water-in-oil or multiple emulsions by the subcutaneous or intravenous route. Vaccines of mixed antigenic types protected mice against challenge with trypanosomes corresponding to each of its components either severally or together, but cross protection between antigenic types was not demonstrated.

Cell walls from “mouse-virulent” strains of Staphylococcus aureus were found to have “aggressin” activity; the addition of isolated cell walls to a dose of staphylococci that was too low to produce any lesion on subcutaneous injection alone led to the formation of a large necro-purulent lesion. Cell walls from “mouse non-virulent” strains did not enhance lesion production in this way. A method of isolating the lesion-enhancing material from the cell walls of mouse-virulent strains is described. This material consists mainly of mucopeptide with some protein but no teichoic acid. It is resistant to heating at 100°C for 10 min., to tryptic digestion, and to treatment with periodate or formaldehyde, but is rendered soluble and subsequently destroyed by lysozyme.

The lesion-enhancing material, when injected subcutaneously into mice on a plug of cotton dust, inhibits the accumulation of oedema fluid at the site of injection. The corresponding cell-wall fraction isolated from mouse non-virulent strains not only failed to inhibit but even stimulated the exudation of oedema fluid.

Diarrhoea and oedema disease were consistently produced in weaned pigs from one breeding farm, but not in pigs from other farms, by the oral administration of Escherichia coli of serotype O141: K85ac. The disease was characterised by the proliferation of large numbers of these organisms in the small intestines a few days after inoculation. Diarrhoea occurred at this time. Signs of oedema disease became evident later when the numbers of the organisms in the small intestine were much lower. These pigs were also susceptible to clinical infection with other pathogenic serotypes of E. coli.

No difference was found between the antibody content of the sera of the susceptible pigs and of the pigs from the other breeding farms that were resistant to the experimental disease. No increase in O or K antibodies occurred in the sera of the susceptible pigs that died or recovered after inoculation with the O141: K85ac strain; anti-haemolytic and bactericidal antibodies increased considerably.

Variation of the protein content of the ration had no obvious effect on the susceptibility of the pigs to infection, but it was not possible to infect pigs given a restricted diet or fed ad libitum on barley fibre.

Four selected smooth strains of Escherichia coli were inoculated orally and intravenously into calves, aged 6–24 hr, whose blood, judged by the zinc sulphate flocculation test, did or did not contain immune globulins (IG+ or IG–), and the numbers of the bacteria in the tissues were estimated when the animals were killed after different intervals. In bactericidal tests in vitro, one of the strains, which belonged to the serotype O78: K80, most commonly found in calves suffering from generalised E. coli infections, survived and multiplied in all samples of IG– serum, but not in most samples of IG+ serum. Two strains, O20: K?: H9 and O20: K?: H–, grew in most IG– and IG+ sera, and the fourth strain, O101: K?, which had been isolated from a calf suffering from the localised intestinal form of E. coli infection characterised by severe diarrhoea, did not grow in any sample of either IG– or IG+ serum.

After oral inoculation into IG– calves, O78: K80 bacteria rapidly invaded the blood and tissues, and their ultimate concentration in the blood was often ten times greater than that in tissues rich in reticulo-endothelial cells. The calves became ill after about 15 hr and soon collapsed and died. Similar results were obtained when O78: K80 bacteria were inoculated intravenously. The blood counts of IG+ calves into which O78: K80 bacteria had been inoculated intravenously were either negative or very low, the highest concentration of the bacteria being found in tissues rich in reticulo-endothelial cells; some of these calves, into which large doses of the O78: K80 bacteria had been inoculated, developed lesions in the kidneys, central nervous system and joints which closely resembled those seen in some natural cases of generalised E. coli infection. The blood and tissues were not invaded after oral inoculation of O101: K? bacteria in IG– calves or of O78: K80 bacteria in IG+ calves; these animals remained well. The distribution of bacteria in IG+ calves into which strains O101: K?, O20: K?: H9 and O20: K?: H– had been inoculated intravenously was similar to that obtained with the 078: K80 strain.

The rate of disappearance of bacteria of strain O78: K80 from IG+ blood in vivo was compared with its rate of disappearance from the same blood in vitro. The bacteria were removed much too rapidly in vivo for the removal to be due wholly or mainly to the bactericidal action of the blood. Similar results were obtained with the O101: K? strain and IG– blood. The O20: K?: H9 and the O20: K?: H– strains disappeared rapidly from the blood of IG+ calves in vivo, yet multiplied in the blood of the same calves in vitro. The O78: K80 strain multiplied in IG– blood both in vivo and in vitro, the rate of multiplication being faster in vitro.

It is concluded that the reticulo-endothelial system constitutes the principal defence mechanism against E. coli bacteriaemia, and that in calves whose blood contains immune globulins as a result of their having been fed with colostrum this protection is of a comprehensive nature.

Thirty-four patients with bronchiectasis were studied for periods of up to 5 yr in an attempt to determine the part played by capsulated strains of Haemophilus influenzae in this disease and the consequent likelihood that type-specific immunisation against such strains would be beneficial. Capsulated haemophili were isolated from sputum from only 5 of the 34 patients and fourfold or greater rises of capsular antibody were observed in only 10 of 33 of the patients who were subjected to repeated serological examinations. These findings indicate that infection of the patients' respiratory tracts with capsulated strains was not unduly common during the period of the study. The patients as a group did not differ significantly in their serum titres of haemophilus capsular antibody from control groups of subjects without lower respiratory tract disease, and therefore had almost certainly not had a greater than usual experience of capsulated haemophili. These findings are in sharp contrast to the existing evidence about the role of the species H. influenzae in chronic bronchial disease, and appear to indicate that capsulated haemophilus strains differ from non-capsulated strains in playing no part in bronchiectasis.

Sendai virus replicates well in the lungs of mice, where it produces extensive damage to the mucous membrane, but no obvious clinical illness. Rapid elimination of virus from the lungs commences after the 5th day of the infection and is associated with a mononuclear response, interferon production and antibody formation. The relative significance of these factors in terminating the infection is discussed.

An atypical case of perinatal infection with Listeria monocytogenes is described, in which the main pathological feature was a congenital bronchopneumonia.

The membranes were intact until just before delivery, and death occurred within 2 hr of birth, but well-established changes were present in the lungs, placenta and mediastinal lymph-nodes, which showed a “monocytoid” reaction. The organism was isolated from both mother and baby and was found to belong to serotype 4b.

DNA-RNA hybridisation was attempted between strains of biotypes A and T of Pasteurella haemolytica. The results indicated that there was a low degree of genetic relationship between the representatives of the two types and suggested that the differences between the types were equivalent to those between different species in other bacterial genera. A high degree of nucleic acid homology was observed between two strains in biotype A.

Rhinoviruses were isolated in 14 of 87 respiratory episodes that occurred in 24 of 44 patients with chronic bronchitis studied for periods up to 2½ yr. Thirteen of these infections were associated with exacerbations of bronchitis. The virus in seven rhinovirus-positive sputum specimens was assayed, and detailed studies of the neutralising antibody responses of the bronchitics to their rhinovirus infections were made. The results suggest that rhinoviruses multiply in the lower respiratory tract and probably stimulate a greater antibody response than that found in non-bronchitic adults. There was no evidence that the rhinoviruses found in the bronchitics were different from those circulating in the normal population. Three of the rhinoviruses belonged to known serotypes and ten of the remaining 11 belonged to eight other types. Representative strains of these eight types have been characterised and submitted as possibly new rhinovirus serotypes.

The growth of different strains of Bordetella pertussis on a variety of media frequently leads to the loss of the surface antigens known as Andersen’s factors 1, 2 and 3. When such suspensions were used as vaccines they were found to be as protective to mice challenged with Bord. pertussis strain 18/323 by the intracerebral route as the parent strains grown in the conventional way and possessing these antigens. Conversely, vaccines prepared from strains of Bord. bronchiseptica and Bord. parapertussis showed poor protection against Bord. pertussis, although they shared type-7 antigen with it.

When antisera were prepared in rabbits by means of suspensions rich in type 1, 2 and 3 antigens and compared with sera prepared against suspensions lacking these factors no clear correlation was found in the protective effect. Some sera rich in agglutinins and others virtually devoid of them proved equally protective in the passive immunity test in mice.

It is therefore suggested that Andersen’s agglutinogens 1, 2, 3 and 7 play no part in the protective effect of vaccines. Some other antigen or antigens must be associated with the protection of mice and presumably also of children.

Skeletal muscle from normal cows and from cows affected with clinical Johne's disease was analysed for nitrogen, protein, hydroxyproline, myoglobin, RNA, DNA, acid soluble ribonucleotides and ATP contents. Creatine phosphokinase (CPK) activity was also assayed in aqueous muscle extracts.

In wasted muscle from cows with Johne's disease the marked reduction in mean muscle-cell size seen histologically was apparently responsible for the increase in DNA content from 0·34 mg per g to 0·87 mg per g fresh muscle. This was confirmed by an associated reduction in non-collagen protein from about 155 mg per g to 125 mg per g and an increase in the proportion of connective tissue (about 35 per cent. measured by its hydroxyproline content).

The mean apparent cellular concentrations of the various muscle constituents expressed in amounts per μg DNA fell to between 30 and 63 per cent. of the corresponding normal values and the mean cell size had decreased from 2·96 to 1·16 mg fresh weight per μg DNA.

ATP content was statistically correlated with muscle CPK activity for both healthy and wasted muscle samples; the reduced cellular concentration of ATP in wasted muscle was therefore probably related to its decreased CPK activity.

Muscular atrophy in Johne's disease may, therefore, be partly associated with a failure of protein synthesis due to a limited availability of ATP via the CPK reaction. Possible precipitating factors are also discussed.

Liver tissue was obtained from 5 cases of clinical Johne’s disease by biopsy and analysed for total nitrogen, protein nitrogen, “collagen”, lipid, nucleic acids, acid-soluble ribonucleotides and ATP. Comparisons were made with liver tissue from healthy cows. The only significant changes in chemical composition were a small rise in liver lipid content and a marked increase in tissue hydroxyproline, indicating increased connective tissue and suggesting early fibrosis.

The in-vitro rate of protein synthesis was assayed in 2 clinical cases and 3 controls by means of the rate of incorporation of [U-14C] leucine into the proteins of liver slices. A higher than normal rate of synthesis was observed in the liver tissue from the cows with clinical Johne’s disease but, at the same time, tissue concentrations of three enzymes (glucose-6-phosphatase, hexose monophosphate dehydrogenase and lactate dehydrogenase) were lowered.

Basophilic cytoplasmic inclusions, often accompanied by nuclear changes, develop regularly in primary monkey kidney cell cultures infected with influenza-B viruses. The inclusions stain positively for RNA, and electron microscopy shows them to contain large aggregates of ribosome-like particles. Inclusions form late in the infection, and it has not been possible to correlate them with the synthesis of virus-specific antigens. The capacity of influenza-B virus to give rise to inclusions is specifically neutralised by virus antibody. The inclusions seem to be a useful character for the distinction of influenza-B strains from other haemadsorbing viruses.

A survey was made of all Trichomonas or Candida (Monilia) infections diagnosed by laboratory methods during 1 yr. Trichomonas infections were diagnosed with over 90 per cent. accuracy by wet-smear microscopy, and similar success rates were achieved by cytological examination and cultural techniques. Candida infections, however, were detected in only 52 per cent. of positive cases by direct microscopy and in only 30 per cent. by examination of cytological smears, whereas 93 per cent. of the cases were proven by culture. It is suggested that wet smears of vaginal exudate should be examined microscopically from all women with excess vaginal discharge or with symptoms of vaginal infection; if wet-smear microscopy is negative, the vaginal fluid should be cultured, even if another lesion is believed to be responsible for the discharge.