The faecal flora of patients with Crohn's disease was compared with that of healthy subjects. In patients with terminal ileitis, numbers of anaerobic gramnegative and coccoid rods (species of Eubacterium and Peptostreptococcus) were higher than in the controls whereas anaerobic gram-positive rods and cocci and aerobes occurred in normal numbers. The composition of the flora was neither influenced by duration of the disease nor by ileocaecal resection. In healthy subjects and patients, a chemically defined diet induced only slight changes in the flora. Thus, the flora in terminal ileitis although stable was permanently abnormal.

In patients with Crohn's colitis, abnormally low numbers of anaerobes were found in patients with severe, bloody diarrhoea while aerobic counts were normal. The flora in patients with mild colitis was similar to that in terminal ileitis. It is suggested that the abnormal flora composition might be an expression of the genetic predisposition to Crohn's disease.

Sera from patients suffering from Crohn's and other diseases and from healthy subjects were tested for agglutinins to anaerobic, gram-positive coccoid rods belonging to species of Eubacterium and Peptostreptococcus. Four strains labelled Eubacterium contortum (two strains), Eubacterium rectale and Peptostreptococcus productus were agglutinated by a higher percentage of sera from patients with Crohn's disease than from healthy subjects and from patients with liver and intestinal diseases (including ulcerative colitis), ankylosing spondylitis, granulomatous diseases, diseases of immunity and malignancies.

The agglutinins were of the IgG and IgM classes and strain-specific; the titres were low.

The results obtained with sera from patients with Crohn's disease and healthy people were subjected to discriminant analysis to estimate the probability, based on the combined results with the four strains, that a patient suffers from Crohn's disease. When sera giving an a posteriori probability ≥ 0·95 (a priori probability = 0·5) were considered positive, the test with four strains had a sensitivity of 54% and a, specificity of nearly 100%. The results with sera submitted for diagnosis showed that positive reactions in patients with a diagnosis apparently incompatible with Crohn's disease were within acceptable limits.

Anaerobic coccoid rods belonging to species of Eubacterium and Peptostreptococcus agglutinate more frequently with sera from patients with Crohn's disease than with sera from patients suffering from other diseases and from healthy subjects. Results of agglutination tests with four strains of coccoid anaerobes were used to estimate the probability that a patient suffers from Crohn's disease. The data on healthy subjects and patients with Crohn's disease were subjected to logistic discriminant analysis. With the methods and interpretation described, 52% of the patients with Crohn's disease were recognized as ‘definite’ or ‘probable’ Crohn's disease and 14% as ‘suspected’. Only 1% of the healthy subjects were classified as ‘suspected’ and none as ‘definite’ or ‘probable’ Crohn's disease.

One hundred and eighty samples of pork sausages were examined after preenrichment in buffered peptone water (P medium), for the presence of salmonellas. From each pre-enrichment four enrichments were made: (1) 0·1 ml of P medium was inoculated into 10 ml of Rappaport's medium, formula R10 (R10/43 °C), (2) 1 ml of the P medium was added to 100 ml of R10 broth (R10/100 ml/43 °C), (3) 1 ml of P medium was inoculated into 10 ml of Muller-Kauffmann tetrathionate broth (MK medium) prepared in accordance with the International Standards Organization document ISO 3565 (MK/43 °C) and (4) 10 ml of P medium were added to 100 ml of MK broth (MK/100 ml/43 °C). All the enrichments were incubated at 43 °C for 48 h. Forty-six and 47 samples were found positive with the first two enrichment methods (R10/43 °C and R10/100 ml/43 °C), while only 16 samples were found positive with the method MK/43 °C, and 27 with the method MK/100 ml/43 °C. The superiority of either one of the two R10 procedures over either one of the two MK methods is statistically highly significant (paired χ2; P < 0·001 in all four comparisons). The superiority of procedure MK/100 ml/43 °C over the method MK/43 °C is also statistically significant (P < 0·005). Both R10/43 °C and R10/100 ml/43 °C procedures had a much stronger inhibitory effect on the competing organisms (lactose- and sucrosenegative) than the two MK methods.

Two recombinants (R22 and R75) of the attenuated B/USSR/69 strain Brigit and the virulent B/Hong Kong/5/72 and one recombinant (R5) of Brigit and the virulent B/Hong Kong/8/73 were selected for genotypic and phenotypic characterization. All three recombinants had the growth property of the attenuated parent Brigit. Analysis of their RNA's by polyacrylamide gel electrophoresis revealed that, the strains R22 and R75 had derived all their genes from Brigit, those coding for haemagglutinin excepted. These recombinants were clinically evaluated and found to be attenuated and immunogenic. The recombinant R5 which derived, besides the gene coding for the haemagglutinin, several other genes from B/Hong Kong/8/73 was only partly attenuated since it induced influenza-like symptoms in one out of three volunteers.

It is concluded that the strain Brigit can be used as a donor of genes for the attenuation of the B/Hong Kong/5/72 virus and that recombinants of influenza type B can be identified, like influenza type A recombinants, by their RNA pattern.

Strains of Escherichia coli isolated from adult females with symptomatic urinary tract infection were found to possess the following properties significantly more frequently than faecal strains: (i) high K-antigen titre; (ii) haemolysin; (iii) type 1 pili; (iv) mannose-resistant haemagglutination; (v) fermentation of dulcitol and salicin; (vi) O serotype 2, 6 and 75; (vii) H serotype 1. E. coli isolated from urine specimens containing significant numbers of antibody-coated bacteria were richer in these seven properties than strains from urines without detectable antibody-coated bacteria.

The O and H serotypes of E. coli obtained from patients with urinary tract infection in two New Zealand cities were compared with those reported in the world literature and found to be similar.

Thirteen definite and 3 probable cases of chlamydial eye infection were diagnosed in young adults attending the Bristol Eye Hospital between June 1978 and May 1980, an incidence of about 1 case per 44000 per year in the 15 to 44-year-old community served by this hospital, and 1 per 100000 in the total population of this community. These patients presented with a sub-acute follicular conjunctivitis or kerato-conjunctivitis, which had usually been present for several weeks and had often failed to respond to topical chloramphenicol treatment before presentation. Sera obtained from 14 patients all had chlamydial antibody titres of 64 or more. Over the same period of time, an estimated 2500 patients per year from the same community attended the Venereology Department at the Bristol Royal Infirmary with genital chlamydial infections. These figures suggest that chlamydial infection of the eye complicates no more than 1 in 300 chlamydial infections of the genital tract in adults.

Of 22 strains of Salmonella gallinarum isolated from recent outbreaks of infection in poultry in Greece (15), Amman (3), Kenya (2), Lebanon (1) and Yemen (1), 20 were more resistant to furazolidone in vitro than 6 strains that had been isolated in the U.K. in the 1950s; the minimum inhibitory concentration of furazolidone was approximately 0·3 μg/ml for the sensitive strains and 1·3 or 2·5 μg/ml for the more resistant strains.

Furazolidone given continuously in the food did not control experimental infections in chickens caused by most of the strains that had been classed as more resistant by the in vitro tests. Chloramphenicol, trimethoprim and sulphadiazine or mixtures of the latter two were the best antibiotics for treating these infections, but they were less satisfactory than furazolidone for treating infections caused by the furazolidone-sensitive strains.

As a group, the furazolidone-resistant strains and furazolidone-resistant mutants of one of the sensitive strains were less virulent for chickens than the sensitive strains.

An experimental model simulating infection of the urinary tract was used to investigate factors influencing the transfer of plasmid-mediated drug resistance in the human bladder in the absence of antibiotic therapy. When a small number of cells carrying plasmid-mediated drug resistance was added to an established population of sensitive cells, it was found that varying the physical conditions of the bladder model had no significant effect on the spread of the plasmid and, under all conditions used, exponential spread of the plasmid through the originally sensitive population occurred. When the initial donor cells were killed shortly after addition to the model, exponential transfer of resistance amongst the established sensitive population still occurred. Thus, even in the absence of antibiotic therapy, only a small number of initial transfer events was required for a fully resistant population to be developed. This was true of both actively multiplying and early stationary phase cultures. An initially greater proportion of resistant cells, or the use of an antimicrobial agent to which some of the cells are resistant, would ensure that this process occurred more rapidly.

Two unidentified mycoplasmas, N3 and N11, isolated from the respiratory tract of horses, were found to cross-react with strains of M. mycoides subsp. mycoides in indirect immunofluorescence tests, growth-inhibition tests carried out by the running drop/agar-well method, and in complement-fixation and double immunodiffusion tests. Serologically, the equine mycoplasmas were not completely identical with any of the reference strains of M. mycoides with which they were compared. Their cultural characteristics, ability to digest coagulated serum and casein, and survival at 45 °C, however, suggested that they were more closely related to strains of M. mycoides subsp. mycoides, such as Y-goat, which are found in goats, than to strains of that subspecies which are pathogenic for cattle.

Short laboratory feeding tests were carried out with the anticoagulants warfarin, difenacoum, and brodifacoum on a number of European rodent species: Clethrionomys glareolus, Microtus agrestis, M. arvalis, Apodemus flavicollis, A. sylvaticus, Mus musculus, Rattus rattus and R. norvegicus. It was found that the toxicity to all species was highest with brodifacoum and lowest with warfarin, and that only 0·005% brodifacoum would give a complete mortality in most species after one day's feeding. The potential of this compound for the control of microtine field rodents is suggested.

A general practice population of around 6700 was kept under clinical and laboratory surveillance from 1962 to 1975. Illnesses totalled 18703 in three morbidity classes: sore throat (Throats) 4451, acute febrile respiratory diseases (FRD) 4934, acute non-febrile respiratory diseases (Non-FRD) 9318. Specimens were examined for beta-haemolytic streptococci (BHS) from 37·1% of these illnesses: from Throats 33·3%, from FRD 67·8%, from Non-FRD 22·6%, and 515 specimens were collected from a miscellaneous (‘Other’) class consisting of healthy persons and ailments that could not have had a streptococcal component.

Strains of BHS were isolated from 7448 specimens as follows: group A (Streptococcus pyogenes) 353, group C 36, group G 15, other groups 274.

Group A strains were isolated from specimens at the following rates: Throats 16·7 %, FRD 2·4%, Non-FRD 0·9 %, Other 1·4 %. The last two classes reflect the carrier rate in the general community, which must be deducted to obtain the streptococcal morbidity in the other classes. Carriers thus accounted for 6% of the strains isolated from the Throats class and for 42 % of those from FRD illnesses.

No consistent seasonal trend of prevalence was detected. Long-term fluctuations in prevalence over several years affected all groups and most group A serotypes.

Serotyping was performed on 304 strains from 1963 to 1975. The commonest types found were T-types 4 and 12 and M-type 12.

Immunity against re-infection by identical strains appeared to be fairly strong and also against heterotypic strains that shared a T-antigen, but little protection was conferred against re-infection by group A strains with no shared M- or T-antigen. R-28 antigen is considered here as a marker epidemiologically equivalent to an M-antigen.

Epidemicity, as measured by a simple estimate of aggregation, appeared to be low and there were differences between and within serotypes.

The infecting organism appeared to linger in the pharynx, sometimes for several months, after a streptococcal illness.

Radial haemolysis (RH) was used to test sera for immunity to rubella from 1317 patients attending a general practice. One hundred and forty-one (10·7%) were treated as susceptible and offered an attenuated virus vaccine (RA 27/3). Pre-immunization sera from 43% of these patients were reactive at low levels in RH (< 15 international units rubella antibody per ml).

Pre- (S1) and post- (S2) immunization sera from 66 vaccinees were studied in detail. Antibody was detected by RH, haemagglutination inhibition (HI) and enzyme-linked immunosorbent assay (ELISA), and the specific IgM response was measured by a solid-phase M-antibody capture radioimmunoassay (MACRIA). The vaccine-induced IgM response was only detected if the S1 serum was non-reactive by all tests for rubella antibody. It was weaker than that seen following wild virus infection. It could be detected reliably for six weeks, and in most cases for nine weeks, after immunization. In contrast, patients with S1 specimens reactive by RH, HI or ELISA never showed an IgM response in the S2 specimen despite ‘significant’ antibody rises often being present.

It was considered that an IgM response to RA 27/3 was the best indicator of pre-immunization susceptibility to rubella. The failure of many vaccinees to make an IgM response implied that a significant proportion were already immune. It is suggested that the threshold for a report of immunity to rubella could be lowered from 15 i.u. antibody per ml and so fewer women immunized without vaccine being withheld from those who need it.

An outbreak of influenza caused by the A(H1N1) subtype in military recruits in February 1978 afforded an opportunity to study the association of ABO blood groups with influenza morbidity and serological response. Fifty-eight per cent of 336 recruits became clinically ill. There was no differential distribution of clinical influenza by blood group. However, seroconversion to a titre of ≥ 20 was significantly and appreciably higher in groups A and B than O and AB. Also, among those with serologically confirmed clinical influenza, the occurrence was significantly higher in groups A and B than groups O and AB.