Antibodies have been used for the last five decades in the laboratory diagnosis of a wide range of diseases caused by viruses and in detailed investigations of virus structure. However, immunological and serological assays have always had problems of interpretation, reproducibility and standardization, resulting partly from the unavoidable heterogeneity of the antibodies in the test. When a mouse, for example, is immunized with a virus, the animal may easily recognise 10–20 different antigenic determinants. As many as five distinct antibodies can be produced by the mouse against each determinant and these will often differ from antibodies made by another mouse against the same antigenic determinant. The method of lymphocyte fusion and the subsequent generation of monoclonal antibodies (Kohler & Milstein, 1975; Kohler, 1980) overcomes these limitations.

Fourteen recirculating cooling water systems were surveyed during the summer, 1981, to see what factors might influence the prevalence of Legionella pneumophila. The effect on the organism of three anti-microbials was studied, each in two systems, by intermittent treatment at two week intervals.

L. pneumophila was isolated from six of the 14 cooling systems at the beginning of the trial but by the end was present in ten. An association was found between the presence of the organism and the concentration of dissolved solids, and chlorides and the pH. There also appeared to be associations with exclusion of light and higher water temperatures.

Repeated tests on eight untreated systems showed that two were consistently infected, three became and remained infected, one was infected on a single occasion and two were never infected with L. pneumophila. Treatment of a contaminated system, either with a 10 p.p.m mixture of a quaternary ammonium compound and tributyltinoxide or slow release chlorine briquettes (maximum recorded free chlorine level 1·2 p.p.m.), did not eliminated legionellae. Treatment of two infected towers with a chlorinated phenol (100 p.p.m.) eliminated legionellae for at least three days, but after 14 days the organism was again found.

Between January 1968 and December 1977, 635 cases of acute bacterial meningitis were admitted to hospitals in the Birmingham Area Health Authority. The epidemiology of these cases was analysed and compared with the 270 cases which were admitted to the regional infectious diseases unit at East Birmingham Hospital (E.B.H.). In children and young adults the meningococcus was the commonest causative organism while over the age of 25 pneumococcal meningitis predominated. Although Haemophilus influenzae was the second commonest infecting organism it was a rare cause of meningitis in school children and adults, only four cases presenting in these age groups in the Birmingham Area.

A detailed analysis was made of the symptoms, signs, laboratory investigations and clinical course of the 270 cases treated at E.B.H.

The mortality in the patients with pneumococcal meningitis was 30%. In the meningococcal group it was 3·5% and in the haemophilus groups 7·7%.

An analysis of the various treatment regimes employed in the 270 E.B.H. patients supports the view that a single antibiotic is sufficient for the therapy of most forms of bacterial meningitis. Intrathecal antibiotic administration is unnecessary in pyogenic meningitis caused by meningococci, pneumococci or H. influenzae.

A retrospective survey was carried out for isolations of salmonellas from humans, foods and sewer swabs from food-handling premises for the period 1976–80.

The predominant serotypes isolated from humans were S. typhimurium, S. hadar, S. virchow and S. agona.

Salmonellas were found in less than 1% of cooked pork and poultry products and were not detected in cooked beef or lamb. The isolation rates for cooked offal and cooked open pet foods were 2·1% and 19·7% respectively. Isolation rates for uncooked meats ranged from 5% for beef to 36% for poultry. Most of the uncooked meats were sausages in which the predominant serotypes were S. derby, S. typhimurium, S. heidelberg and S. panama.

An attempt was made to investigate the relationship between serotypes isolated from humans and from sausages and sewer swabs. S. typhimurium and S. bredeney were predominant in humans, sausages and sewer swabs whilst S. derby, S. panama and S. give were predominant only in sausages and sewer swabs.

An international collection of 419 isolates of Salmonella agona was phage typed, biotyped and colicine typed. Of 16 recognized phage types, 15 were represented. Three phage types (I, V and XVI) accounted for 84% of all isolates, were widely distributed and may be interconvertible. Biotyping afforded little type differentiation; thus 92·6% of the isolates belonged to biotype 1 a. A rhamnose non-fermenting variant line (of biotype 5a) became established in Zaire from 1979 to 1980. A maltose late-fermenting line of biotype 1 a, isolated in Scotland in 1974, did not thereafter become established. Two Col+ lines (producing colicine I b) accounted for 45 of 68 colicinogenic isolates. The implication of type diversification and the phylogenetic significance of these findings are discussed.

Nasal swabs were taken from 369 four-year-old children in two South Wales towns and cultured for Streptococcus pneumoniae. The organism was isolated in 34% of the specimens, similar rates being found in boys and girls in the two towns. The children were swabbed again a year later, when the prevalence of nasal pneumococci had fallen to 25%. There was no association between the presence of the organism on the two occasions. Types 6 and 23 were most often isolated. After excluding children who had received an antibiotic, the proportion carrying a pneumococcus was higher in those who had recently had a respiratory infection than in the rest, although the difference was not quite statistically significant. There was a significant negative association between the presence of Staphylococcus aureus and Strep. pneumoniae.

Nasal carriage of Staphylococcus aureus was studied in a cohort of infants born to the residents of two towns in South Wales. The children were followed up to the age of 5 years, nasal swabs being taken annually after a more detailed survey during the first year. The carriage-rate of S. aureus reached a minimum of 10–15% at one year and then rose steadily to 41% at five years. From the age of two years about 90% of the organisms isolated were resistant to penicillin. There was a marked tendency for children to carry the same strains from year to year, but carriage during the first year of life did not predict carriage at the age of five.

The results of typing all group A streptococci isolated in one laboratory in 5 years were reviewed to see if the collected information showed epidemiological patterns. The great majority of the 5858 streptococci typed came from patients seen in general practice: 72% from throat swabs and 11 % from skin lesions. Eight types, M types 1, 2, 3, 4, 6, 12, 22 and type 28 R accounted for 65% of strains. These eight types had different patterns: types 2 and 6 caused small circumscribed outbreaks and were uncommon between epidemics; types 3, 4 and 12 caused larger, wider epidemics, whereas types 1, 22 and 28 R had a more stable pattern. Type 4 was more commonly resistant to tetracycline than most other types, a finding which affected the apparent incidence of tetracycline resistance in group A streptococci. Streptococci from superficial sites were more likely to have serum opacity factor and to lack a detectable M-antigen than strains isolated from the throat. Routine typing of streptococci helped to detect outbreaks of infection in special groups. It is concluded that regular streptococcal typing should be continued in some places.

An immunosorbent assay using solid-phase attachment of red cells (SPARC) was used for the detection of rubella-specific IgM. The method is described and the results compared with those obtained by the IgM antibody capture radioimmunoassay (MACRIA). One hundred and ninety-nine sera were investigated for the presence of rubella-specific IgM and only one discrepant result occurred, namely a false positive obtained by MACRIA in a patient with infectious mononucleosis. Rheumatoid factor, heterophile antibody, and rubella-specific IgG did not interfere with the results obtained by the SPARC technique. Advantages of the SPARC technique include the ease and lack of expense of testing large numbers of sera, the small volume of sample required and the fact that pretreatment of serum is not necessary.

Attempts were made to isolate viruses from babies' stools that contained adenoviruses detected by electron microscopy. One hundred and fifty-nine specimens from 71 children were studied and adenoviruses of established serotypes were isolated from 81 stools. Serial stool samples containing adenovirus particles were obtained from 35 children, and prolonged shedding of recognized serotypes was common. Simultaneous and sequential infections by different serotypes were also observed. Thirty-six children shed adenoviruses that could not be isolated using cell cultures normally used to detect adenoviruses, and nine of these children also shed adenoviruses of established serotypes. Passage in Chang conjunctival cell cultures allowed characterization of fastidious adenoviruses from 14 children as members of a previously unrecognized serotype.

Two Bordetella pertussis antigen preparations, outer membrane protein (OMP) and filamentous haemagglutinin (FHA), and a standard vaccine were used to immunize rabbits, and the effects on nasopharyngeal colonization by the organism were determined. Antibodies were measured in serum and in nasal washes by ELISA before and after challenge of the rabbits with 106 bacteria of strain M2. Recoveries of B. pertussis in nasal washes were used to assess colonization, which in controls persisted for at least 65 days. Some rabbits of all the immunized groups showed enhanced clearance, but there was no correlation between the elimination of B. pertussis and serum antibodies to OMP, FHA, lipopolysaccharide, lymphocytosis-promoting factor or agglutinogen 3. In contrast, nasal IgA antibody to FHA showed significant inverse correlation with bacterial persistence. Such antibody was induced by the OMP preparation as well as by FHA, but to different extents depending on the immunization schedule and adjuvant used.

Dispersal of non-sporeforming anaerobic bacteria was studied. Skin samples were taken from the subjects, and dispersal from different parts of the body was examined.

The number of anaerobic bacteria dispersed was not correlated to their density on the surface of skin area exposed. The highest density of anaerobic bacteria on the skin was found in the face and upper trunk, but the highest yield of anaerobic bacteria dispersed came from the lower trunk.

The dominant anaerobic bacteria dispersed were Propionibacterium acnes, but Propionibacterium avidum, Propionibacterium granulosum and Gram-positive cocci were also isolated from the dispersal samples. Peptococcus magnus was the most common coccus isolated. For the less frequently isolated bacteria, the best correlation was found between the perineal flora and airborne bacteria.

A comparison was also made of bacterial dispersal by naked and dressed subjects. The dispersal of both aerobic and anaerobic bacteria was higher when the subjects were dressed in conventional operating theatre cotton clothing than when they were naked.

The increased dispersal of anaerobic bacteria when the subjects were dressed was mainly due to increased dispersal of Propionibacterium sp.

The laboratory surveillance of influenza in the UK has continued to demonstrate the regularity of influenza outbreaks each winter even in the absence of increase in the other indices which reflect the morbidity and mortality associated with influenza.

The period of five years from 1976 to 1981 has seen the appearance of a second sub-type of influenza A with the return of the historic H1N1 virus; and the continued circulation of H3N2 concurrently with H1N1 virus. Variants of both these influenza A viruses have been demonstrated as well as further changes in the strains of influenza B virus isolated during this time.

Strains of Escherichia coli were isolated from laparotomy specimens from Chinese patients with recurrent pyogenic cholangitis in Hong Kong. A large variety of serotypes were found. Several sites were sampled in each patient. While only one serotype was normally isolated from one site, different sites often yielded different serotypes in the same patient. Generally the ‘O’ types found did not correspond to those found in the faeces of the Hong Kong Chinese population.

Measles virus-specific antibodies in sera from patients with HBsAg-negative chronic active hepatitis and raised antibody titres against measles virus, have been examined by crossed immunoelectrophoresis. The immunoprecipitates were further analysed by SDS-polyacrylamide gel electrophoresis. Five measles virus-specific precipitation lines were demonstrated using measles virus-infected cells solubilized with Triton X-100. The three major precipitation lines were analysed by SDS-PAGE and contained the virus polypeptides: nucleoprotein, NP (MW ∼ 60000); haemoagglutinin, H (MW ∼ 80000) and fusion protein F1 (MW ∼ 40000). Considerably higher amounts of antibodies against these three virus polypeptides were demonstrated in the patient sera than in sera from healthy controls. By SDS-PAGE analysis of radiolabelled immune complexes adsorbed to Sepharose-protein A, antibodies against five measles virus polypeptides: NP, H, F1, P protein (MW ∼ 70000) and matrix protein, M (MW ∼ 37000) were demonstrated in the patient sera.

It is now established that milk can be a vehicle for the spread of enteritis due to Campylobacter jejuni. By determing the lethal effect of heat on six isolates it has been shown that C. jejuni is unlikely to survive pasteurization.

During the past year five patients from countries in the Middle East admitted to a burns unit were found to harbour a strain of Staphylococcus aureus with unusual multi-resistance to antibiotics. The admission of the first patient was followed by an outbreak of infection with this strain involving ten patients in the unit. In addition five staff members were found to be nasal carriers of the strain. As a result of this incident, the following four patients admitted to the unit were isolated on admission and the spread of their strains was thus prevented. It is recommended that patients on admission to burns units, or similar departments with patients very susceptible to infection, are isolated until their bacterial floras have been examined.

A total of 2973 Escherichia coli, isolated from six different groups of animals, were examined for their ability to ferment adonitol, dulcitol, raffinose, rhamnose and sorbose in solid media. Twenty-nine fermentation patterns were recorded although 2443 (82%) of the E. coli belonged to seven of the 32 possible biotypes. Ninety-six O-serotypes were identified within the 2973 E. coli. The number of O-serotypes represented in the 15 most common biotypes ranged from three to 15. Sero types O8 and O9 were found most commonly in the different groups of animals and several biotypes amongst these two O-serotypes were identified in two or more groups of the animals. The ability of the E. coli to metabolize aesculin, ornithine, salicin and sucrose was also assessed. These tests proved less reproducible and were not included in the primary biotyping scheme although their use allowed the enumeration of additional biotypes. The application of biotyping to the study of the ecology of drug-resistant strains of E. coli in five situations is briefly presented.

Salmonella typhimurium phage type DT 193 survived in small numbers, in stored static slurry derived from veal calves, for the 7-week period of observation. The viable coliform count fell by 1½ logs during the first 2 weeks of storage, thereafter there were only relatively small fluctuations in the coliform population. In all 735 of 752 Escherichia coli isolates examined from eight samples of slurry were resistant to 3–6 antibacterial drugs. There was no dramatic change in the overall level of drug resistance amongst the E. coli with time. Chloramphenicol resistance was recorded in 400 (55%) of the E. coli. It was always associated with multiple resistance, with 96% of the strains being resistant to 5 or 6 drugs, although the proportion of isolates of each of the ten most prevalent O-serotypes resistant to chloramphenicol was variable and ranged between none and 97·5%. The use of biotyping together with O-serotyping indicated that the E. coli population was extremely complex, although certain components of the population remained relatively stable within the dominant flora with time since several of the more common O-serotype/biotype combinations were isolated from more than half of the eight slurry samples examined.

The virulence of faecal and urinary Escherichia coli strains was studied in relation to serotype, haemolysin production and haemagglutination pattern. By means of an experimental mouse model E. coli strains can be divided into avirulent (I), mouse nephropathogenic (II), and generally virulent (III) strains. Virulent group II and group III strains were more often haemolytic and haemagglutinating than avirulent group I strains. Presence of K antigen could not be associated with virulence. Discriminant analysis for qualitative variables revealed that no combination of the investigated properties contributed more to a strain's virulence level than did one single property. It is concluded that other virulence factors, apart from haemolysin production in group II strains and haemagglutinins in group III strains, must be involved in the determination of a strain's virulence level.

All O2, O6 and O18ac strains tested were virulent, and by far the most O75 strains were avirulent, whereas other O groups were more variable with regard to virulence. Pyelonephritis strains were more often mannose-resistant haemagglutinating than faecal and other urinary isolates, indicating that mannoseresistant adhesins may be important in the pathogenesis of pyelonephritis.