Samples of Fermi, Semple, modified Semple, Duck embryo and tissue culture rabies vaccine were inoculated by different routes and in different doses into rabbits, mice and hamsters. The vaccines induced neither detectable interferon nor immediate protection against lethal challenge with CVS rabies virus.

Under similar conditions, high but transient levels of interferon were induced in control animals of the same species with the polynucleotide complex Poly I.C. Hamsters but not mice were protected by Poly I.C.-induced interferon.

No autointerference by vaccine with challenge virus was established. Vaccineinduced protection in mice was directly related to immune response.

Arguments in favour of biotyping of Enterobacteriaceae excreted in the faeces of isolated patients, as a method of investigating the efficiency of the isolation procedures, are presented as well as a technical outline of the procedure. The study included three kidney transplantation patients, five acute myeloid leukaemia patients and four healthy persons as controls.

The results show, apart from new colonizations during isolation, a difference in the mean number of contaminations and colonizations with different Enterobacteriaceae biotypes. It is concluded from these results, that the isolation procedures were not completely effective and that the AML patients studied had a decreased colonization resistance of their digestive tract. This was less evident in the kidney transplant group.

Influenza virus may be precipitated and aggregated by polyethylene glycol into clusters comprising ten to many hundred virions per aggregate. These aggregates are sparingly soluble and may be freed of contaminating polymer by washing in the appropriate buffer at room temperature or by precipitation in 30 % (v/v) ethanol at subzero temperatures.

Immunogenic studies in guinea-pigs of the virus in different states of dispersion revealed that the aggregated virus is the superior antigen to the virus in the monomeric form or in the dissociated state following treatment with ether.

In a comparative study of 24 different rubella virus strains, all but three formed small plaques in RK 13 cell cultures; of these one was the vaccine strain HPV-77, one was isolated from a congenitally infected infant, and the third was recovered from an adult who contracted severe rubella while handling this congenital strain. Whereas the plaque size of the vaccine strain was stable after further passage in cell culture, the plaque size of the other two rapidly diminished when the virus was passed in monkey kidney cells, and one of them was also reduced by passage in RK 13 cells. Cell culture passage of the typical small plaque strains did not result in altered plaque size.

Using animal inoculation, three out of six Lebanese and three out of nine Argentinian and two out of two Pakistan separate commercial consignments of bone meal imported during 1970 were found to be infected with anthrax.

The colour-change and lead acetate tests for fermentation of d–, l–and m–tartaric acids and citric acid used in the Kristensen scheme for biotyping Salmonella typhimurium were found to be unreliable because, whatever the conditions of culture, they gave different results in replicate tests of the same strains. Many genotypically non-fermenting strains gave inconsistent reactions due to the emergence of fermenting mutant bacilli in some of their test cultures. No reliable test was found for the fermentation of citric acid.

A ‘turbidity’ test was found to give consistent and reliable results with the three tartaric acid isomers. It demonstrated fermentation by the significantly greater amount of growth obtained in a 24 hr. culture in Oxoid peptone water with added isomer than in a control culture without isomer. Lewis & Stocker's (1971) plate-inhibition test for fermentation of m–tartrate, which identifies m–tartrate-negative strains because m–tartrate inhibits their growth on citrate- or glycerol-containing minimal medium, was found to be as reliable as, and easier to read than, the turbidity test.

Use of the turbidity test for d–and l–tartrates and the plate-inhibition test for m–tartrate in biotyping 1435 strains of S. typhimurium showed that many strains had previously been mistyped by the lead acetate test and distinguished 16 new biotypes in addition to the 22 biotypes already recognized.

Host ranges of members of four groups of male-specific RNA coliphages were determined by plating on hosts carrying various derepressed plasmids. An RNA phage originally isolated on Pseudomonas aeruginosa failed to form plaques on any of the strains of Escherichia coli.

Serum proteins from Mycoplasma gallisepticum culture medium could be detected on the organisms as a result of incubation at low pH. Only certain of the serum proteins, including IgG and IgM, were found, and the adsorption appears to depress the haemagglutinating activity of the organisms. There was no obvious effect on slide agglutination (SA) sensitivity but an incidental finding was that brief acid treatment enhanced the SA sensitivity of an antigen prepared from a young culture.

The incidence and acquisition of Candida albicans and other yeasts in two wards of a skin hospital is described. Carriage rates on the skin in hospital patients is higher than is generally supposed, and cutaneous sites may act as sources of infection with these organisms.

Osmotic injury in frozen-thawed T4 phage was caused by the sudden and large fall in the electrolyte concentration of the unfrozen aqueous phase during rapid thawing of frozen samples. In accordance with the classical interpretation of osmotic shock it was found that DNA was quantitatively liberated from T4 phage inactivated by the osmotic injury of rapid thawing.

The degree of inactivation of osmotically shocked T4 phage was temperature dependent, being much increased by lowering the temperature, but was independant of the pH of the suspending medium. The T4Bo osmotic shock-resistant phago was refractory to the osmotic injury of rapid thawing.

A simple and convenient particle tracer for studies of the effectiveness of isolation units and other places in limiting the airborne transfer of bacteria is described. Particles of potassium iodide 7–8 µm. diameter are generated by spraying from solution and collected on membrane filters. The particles can be identified by development with 0·1 % acid palladium chloride solution, when dark brown spots approximately 100 µm. in diameter are produced.

This paper describes a search for Gram-negative bacteria in an operating theatre and the steps taken to reduce the level of environmental contamination.

A high rate of infection in clean wounds prompted a bacteriological survey. Potential sources of infection found, and the measures employed are described in the hope that others may be encouraged to examine familiar equipment critically and to improve hygiene even in old premises.

The choice, design, use and care of cleaning and sterilizing equipment were open to criticism. In particular, a currently popular floor-scrubbing machine provided a breeding ground for Pseudomonas aeruginosa and was distributing it in the theatre environment.

Values are deduced for the efficiency of isolation against airborne particulates, e.g. micro-organisms, of a variety of ventilation systems. The calculated values show reasonable correspondence with the limited experimental data available. Much better control and indication of the air flow is necessary if high degrees of isolation are required.

The complement-fixation test, as commonly used in the diagnosis of viral infections, was studied for its possible application to the diagnosis of whooping cough and the detection of antibody following pertussis vaccination. The results were compared with those obtained in parallel immunofluorescence tests. CFTs were performed on sera from 41 patients with whooping cough (Bordetella pertussis isolated), 125 vaccinated persons, and 618 controls; parallel tests by IP were made on sera from 24 cases of whooping cough, 36 vaccinated persons and 37 controls. Results of both tests correlated closely and showed that titres of diagnostic significance were seldom found in control sera. They also showed that, in patients suffering from whooping cough, antibody in a single specimen or a rise in antibody between paired sera was almost always demonstrated. Titres in general were lower in infants less than 6 months of age. IgG antibodies were involved in both tests. Although the number of sera tested was small both tests appear to be reliable as means of demonstrating the presence of antibody formed during the course of infection and after vaccination.

Peptides of rabbit globin produced by tryptic digestion, were found to be highly protective against inactivation of freeze-thawed T4 phage. In concentrations of about 10−3 M the peptides protected the phage against inactivation by both concentrated NaBr in the unfrozen aqueous phase and the eutectic phase change.

Fractionation of the poptides by G25 Sephadex showed that peptide concentration rather than peptide size was the more important factor in determining the degree of protection of the phage by electrolyte effects. In contrast, protection against eutectic injury was strongly dependent on peptide size.

Possible mechanisms of action of the protective peptides are discussed.

Four hundred and sixty-seven serum specimens from the female students at a residential college were examined for the presence of circulating antibody to human wart virus using the technique of counter-current immunoelectroosmophoresis. A significantly higher incidence of antibodies was found in students with a past history of plantar warts than in any other group. Antibody took several months to develop and was detectable in 20–30 % of the students up to 9 years after infection. From a few cases of multiple infection, it was shown that reinfection could occur in spite of the presence of circulating antibodies probably of the IgG class. The sensitivity of the test was compared with two recognized techniques for detection of wart virus antibodies, namely gel diffusion and passive haemagglutination.

The indirect immunofluorescent technique has been used to study the specific immunoglobulin responses in twelve adult cases of acute uncomplicated rubella. IgG, IgA and IgM antibodies increased virtually simultaneously. IgG antibody persisted throughout the period of study but showed a slight tendency to fall in titre after 7 months. IgM antibody was detected in nine cases. In these patients it was present in high titre 5–15 days after the rash but was not detected after 20 days. IgA antibody was detected in all cases. It was present in high titre 5–20 days after the rash but was no longer detectable after 29 days except in one patient who had a very low titre at 78 days. The presence of specific IgA and IgM indicates recent rubella in uncomplicated cases, and if the immunofluorescent method is used both types of antibody should be sought.

Airborne-particle transfer has been studied in a burns unit using potassium iodide particles. The observed rates of transfer were in good agreement with the values predicted by a theoretical model.

An estimate of the average transfer between rooms under conditions of normal activity and with correctly functioning ventilation showed that the isolation system was highly efficient, the proportion transferred being probably less than 1 in 105. However, the ventilation often did not function as designed and under these conditions the efficiency was reduced by a maximum of a factor of ten. These rates of transfer do not seem great enough to account for the high rate of cross-infection found in this unit.

The membrane methods described in Report 71 on the bacteriological examination of water supplies (Report, 1969) for the enumeration of coliform organisms and Escherichia coli in waters, together with a glutamate membrane method, were compared with the glutamate multiple tube method recommended in Report 71 and an incubation procedure similar to that used for membranes with the first 4 hr. at 30°C., and with MacConkey broth in multiple tubes. Although there were some differences between individual laboratories, the combined results from all participating laboratories showed that standard and extended membrane methods gave significantly higher results than the glutamate tube method for coliform organisms in both chlorinated and unchlorinated waters, but significantly lower results for Esch. coli with chlorinated waters and equivocal results with unchlorinated waters. Extended membranes gave higher results than glutamate tubes in larger proportions of samples than did standard membranes. Although transport membranes did not do so well as standard membrane methods, the results were usually in agreement with glutamate tubes except for Esch. coli in chlorinated waters. The glutamate membranes were unsatisfactory. Preliminary incubation of glutamate at 30° C. made little difference to the results.

Extraction of membranes of Mycoplasma hominis with n–butanol showed that antigenicity was associated with thenon-lipid residue, which probably consisted mainly of protein, and not with the lipid itself.

Since many membrane proteins are hydrophobic, membranes were rendered soluble in various ways. Extraction with urea or phenol was the most successful, yielding extracts which were both antigenic and serologically reactive. The urea extract could not be fractionated by polyacrylamide disk electrophoresis or by column chromatography. However, serologically active components identified by gel diffusion were separated from detergent-lysed membranes by polyacrylamide disk electrophoresis. The activities of antisera against these fractions suggested that indirect-haemagglutinating or metabolic-inhibiting antibodies can be directed against several different membrane antigens. However, the antigens identified by gel diffusion probably do not represent all the components participating in indirect haemagglutination.

Treatment of membrane suspensions with heat, alkali, periodate and various enzymes showed that the four components identified by gel diffusion could be distinguished by their differing stabilities and properties. On the basis of their lability and susceptibility to proteolytic enzymes, two were identified as proteins.