One hundred and ninety-two strains of Neisseria gonorrhoeae isolated from migrant mine-workers were tested for their susceptibility to antibiotics, auxotyped and serotyped. Of the total, 93 (48%) were acquired locally and 64 (33%) from different geographical locations. Plasmid-mediated resistance to penicillin was found in 28 (14·6%) strains and was associated predominantly with the presence of 5·0 kb penicillinase encoding plasmid (18/28, 64%). Chromosomal resistance to penicillin (MIC ≥ 1 mg/l) was detected in 14 (7·3%) strains. Resistance to tetracycline was chromosomally and not plasmid-mediated. Antibiotic resistance was encountered most commonly among strains acquired in Natal. The overall gonococcal population was sensitive to ceftriaxone, ciprofloxacin. spectinomycin and azithromycin. Nine auxotype/serovar (A/S) classes were encountered among penicillinase-producing N. gonorrhoeae (PPNG) compared to 24 A/S classes among non-PPNG strains. The most common A/S class was NR/IA-6 which accounted for 38% of PPNG and 15% of non-PPNG.

Routine surveillance of infection in England and Wales detected 394 cases of campybacter bactermia in 11 years. This represented an average incidence of 1.5 per 1000 intestinal campllobacter infections, with range of 0.3/1000 in children aged 1–4 years to 5.9/1000 in patients aged 65 years or more. Definitive identification of 257 isolates showed that 89% were Campylobacter jejuni or C. coli: other species were C. fetus (8.6%). C. lari (0.8%), C. uspaliensis (0.8%). helicobacter (Campylobacter) fennlliae (0.8%), and Helicobacter (Camphlobacter) cinaedi (0.4%). Most (71%) of the C. jejuni/C. coli bacteraemias were in pastients with acute enteritis. Of the patients with C. fetus bacteremias only 27% had diarrhoea: they were older than patients with diarrhoae: they were older than patients with C. jejuni or C. coli bacteremia (54.1 r. 45.9 years) and proportionally more of them were male (M:F retio 2.7: 1 v. 1.9:1): 41% had endovascular pathology or cellulitis. There was a higher proportion of C. jejuni serogroup O 4 (Penner) and O 18 strains among blood than faecal isolates. Which suggests that they were unsually serum resistant and/or invasive.

A total of 79 Australian isolates of beta-haemolytic Escherichia coli from cases of porcine postweaning diarrhoea (PWD), and 18 isolates of serotype O 149:K91:K88 (F4) from unweaned pigs from Australia, Indonesia and Denmark, were examined by multilocus enzyme electrophoresis. These were divided into 57 electrophoretic types (ETs), with an overall mean genetic diversity per enzyme locus of 0·466. This value closely resembled that previously recorded for the whole species. Not only was the collection diverse, but there was considerable genetic heterogeneity amongst PWD isolates of the same serogroup. Isolates from serogroups O 8 and O 138 were most varied, whilst many from serogroups O 141 and O 149 were more closely related. In contrast, the isolates from the unweaned pigs all belonged to only one ET.

A total of 12902 neonatal samples collected on absorbent paper for routine metabolic screening were tested anonymously for antibodies to toxoplasma. Seroprevalence varied from 19.5% in inner London, to 11.6% in suburban London, and 7.6% in non-metropolitan districts. Much of this variation appeared to be associated with the proportions of livebirths in each district to women born outside the UK. However, additional geographical variation remained and seroprevalence in UK-born women was estimated to be 12.7% in inner London, 7.5% in suburban London, and 5.5% in non-metropolitan areas. These estimates are considerably lower than any previously reported in antenatal sera in the UK. The wide geographical variation highlights a need for further research to determine the relative importance of different routes of transmission.

Sampling of sera from 202 Sudanese and 124 Swedish children 1–14 years of age was conducted at the end of the 1980s presenting an opportunity to compare the seroprevalence of anti-Neisseria meningitidis (MC) serogroup A antibodies in an area immediately before outbreak of an epidemic (Sudan 1988) with a low endemic area (Sweden). An ELISA antibody assay was developed for detection of antibodies against capsular polysaccharide of MC serogroup A and Haemophilus influenzae type b (Hib). Serum antibody against MC serogroup A was found significantly more frequently in Sudanese than in Swedish children. This indicates that factors other than herd immunity, as measured by serum antibodies against MC serogroup A polysaccharide, are important for avoidance of an MC serogroup A epidemic. The seroprevalence of Hib antibodies was, in contrast, significantly higher in Swedish than in Sudanese children, especially for 5–9-year-old children. A possible explanation may be the different systems of day-care of children in the two countries.

An outbreak of non-bacterial food poisoning presumed due to small round, structured viruses (SRSV) occurred at a national conference.

A detailed postal survey of all conference attenders was carried out to ascertain the cause of the outbreak and 355 questionnaires were returned.

Univariate analysis showed that mussels in the seafood cocktail were the likely vehicle of infection. A dose–response relationship between the amount of seafood cocktail consumed and the risk of illness was demonstrated. Dose–response has not previously been documented in a food-borne outbreak due to small round structured virus.

Detailed quantitative food histories can be useful in eliciting dose-response relationships and may be crucial in establishing the vehicle of infection when investigating food poisoning following consumption of a set-menu meal. Their use should be considered in other outbreak situations.

Sanitation is an important problem in relation to the control of pests in urban environments. This investigation analysed the potential risk related to the presence of cockroaches and their capacity for disseminating bacteria in six different types of buildings: hospital nursing area and out-patient area, swimmingpool pool-side and toilet area, low-income flats and food-handling places. Fifty-six species of bacteria were identified from 157 samples. 14 of these have previously been reported as potentially pathogenic for man and vertebrates. Similarities were found between samples collected in (a) the hospital out-patient area and foodhandling establishments and (b) the hospital nursing area and flats. Pool-sides possessed a poorer bacterial flora. There was a greater bacterial specific diversity in food-handling establishments, flats and swimming-bath toilet area. Enterobacter cloacae, Klebsiella pneumoniae and Klebsiella oxytoca were dominant species in flats and the hospital nursing area. Therefore, cockroaches can play a role in disseminating bacteria, which they can carry passively on their cuticle.

Between November 1990 and February 1991 101 gull faecal samples, collected in central Scotland, and 50 cloacal lavages, from gulls captured at two refuse tips near Durham, England were examined for the presence of Cryptosporidium sp. oocysts. Five of 101 (c 5%) of faecal samples and 11 of 50 (22%) of cloacal lavages contained oocysts, of which 64% and 83%, respectively were considered viable when examined with propidium iodide and 4′-6-diamidino-2-phenylindole. Since there is insufficient evidence to ascribe these oocysts to a recognized species they are therefore referred to as Cryptosporidium sp. oocysts. There were significant differences in the occurrence of oocysts between gulls captured at the different refuse tips (P < 0.01), but no significant difference between the distribution of oocysts in two species of gull, Larus argentatus (Herring Gull) and L. ridibundus (Black-head Gull). The differences may be explained by different food sources and feeding habits. The contribution of gulls to environmental contamination with Cryptosporidium sp. oocysts is probably generally small, but may be more significant when large numbers roost on surface waters.

This survey reports the results of investigations performed by the Laboratory of Enteric Pathogens (LEP), to identify evidence of human infection with Vero cytotoxin-producing Escherichia coli (VTEC) in the UK during the period 1989–91. Bacterial isolates, faecal specimens and serum samples were received from patients suffering from diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome. Using serotyping, Vero cytotoxin gene probing and an ELISA for serum antibodies to E. coli 0 157, evidence of infection was detected in 232, 428 and 615 individuals in 1989. 1990 and 1991 respectively. Of these individuals, 15% were reported as having HUS. Vero cytotoxin-producing E. coli O 157 was the most frequently encountered serogroup. with isolations from a total of 1092 individuals over the 3-year period. The incidence of VTEC infection increased from 0·41/ 100000 in 1989 to 1· 07/100000 in 1991. The area with the highest rate of infection in each year was Scotland, increasing from 1–37/100000 in 1989 to 3·97/ 100000 in 1991.

Only a small proportion of animals tested were found to be excreting Fusobacterium necrophorum biovar A, the causative organism of necrobacillosis, in the faeces (3 of 69 wallabies, 1 of 66 deer, 2 of 81 cattle). The two positive cattle belonged to a single group of calves on a farm with a history of necrobacillosis and the litter underfoot also readily yielded biovar A organisms. All attempts to demonstrate biovar A in litter on other farms and in soil from an area populated by wallabies and deer failed. Ruminal contents from young beef cattle proved a fertile source of F. necrophorum biovar A, 15 of 18 animals giving a positive result. It is suggested that disturbance of the gastrointestinal microflora leads to intestinal multiplication and faecal excretion of the organism, which may then give rise to necrobacillosis of the body surface.

Investigations of respiratory illnesses and infections in Tecumseh. Michigan. USA, were carried out in two phases, together covering 11 years. During the second phase, there were 5363 person-years of observation. Respiratory illness rates in both males and females peaked in the 1–2 year age group and fell thereafter. Adult females had more frequent illnesses than adult males; illnesses were less common in working women than in women not working outside the home. Isolation of viruses fell with increasing age; rhinoviruses were the most common isolate. Influenza infection rates, determined serologically, suggested relative sparing of young children from infection with type A (H1N1) and type B. Infection rates were highest in adult age groups for type A (H3N2). The isolation and serological infection rates were used to estimate the extent to which laboratory procedures underestimated the proportion of respiratory illnesses caused by each infectious agent; data from other studies were also used in this estimation. Severity of respiratory illnesses was assessed by the proportion of such illnesses that resulted in consultation of a physician. Rhinoviruses produced the greatest number of consultations. Overall, physician consultations were associated with 25.4% of respiratory illnesses.

Between June 1990 and July 1991, broiler chickens from 49 flocks from 23 farms were examined for the carriage of Campylobacter jejuni at slaughter. Thirty-seven flocks (76%) were campylobacter-positive. Prevalence of campylobacter-colon-ization was not associated with any of a variety of factors such as water source and broiler house floor structure. There was also no apparent seasonal variation in carriage. Investigations on one farm indicated that dipping boots in disinfectant before workers entered broiler houses either delayed or prevented colonization with C. jejuni.

Oral pretreatment of mice with either a mixture of kanamycin and erythromycin or metronidazole to modify the gut microflora greatly enhanced the faecal excretion of Fusobacterium necrophorum biovar A given by mouth. This lends support to the suggestion that disturbance of the gastrointestinal microflora in animals such as cattle, which often carry the organism in the rumen, may lead to intestinal multiplication and faecal excretion, thereby providing a source of infection that may lead to necrobacillosis of the body surface.

Analysis of cloacal samples collected from 12321 wild ducks in Alberta, Canada, from 1976 to 1990 showed influenza A infections to be seasonal, with prevalences increasing as the population became increasingly more dense. Viruses with 3 haemagglutinin (H3, H4, and H6) and 3 neuraminidase subtypes (N2, N6, and N8) were found consistently to infect both adult and juvenile ducks each year, indicating that wild ducks may be a reservoir for these viruses. In contrast, viruses with 7 haemagglutinin (H2, H5, H7, H8, H9, H11, and H12) and 3 neuraminidase subtypes (N1, N3, and N4) were not found for prolonged periods during the study; when they were found, they primarily infected juveniles at moderate levels. Whilst wild ducks appear to perpetuate some influenza A viruses, they apparently do not act as a reservoir for all such viruses.

The occurrence and nature of bacteriologically confirmed tuberculosis due to Mycobacterium tuberculosis in South-East England in the period 1984–91 is reported and compared with the results of a study for 1977–83. Registered new cases reached a low of 1028 in 1988 but increased to 1252 in 1991. This appeared to be due to a halt in the previous decline in new cases of European patients, a small increase in the number of Indian subcontinent (ISC) patients and an increase in patients from Africa. A total of 122 patients, mostly of European ethnic origin, were known to be HIV positive. As in the 1977–83 study, disease in the ISC group affected younger patients than in the European group, tubercle bacilli were more frequently isolated from a non-pulmonary site in the ISC group (45%) than in the European group (19%) and there was a higher incidence of the South Indian variant of M. tuberculosis in the former group (17%) than in the latter (9%). The overall incidence of drug resistance has not altered significantly since the 1977–83 study but 46 strains resistant to 3 or more drugs were isolated from 4099 ISC patients, compared with 3 of 4594 strains from European patients. Six of the 122 isolates from HIV positive patients were drug-resistant but none was multi-drug resistant.

The slight rise in registered bacteriologically proven cases of tuberculosis, the presence of multi-drug resistant strains, the occurrence of HIV-related tuberculosis and reports of the emergence of multi-drug-resistant HIV-related tuberculosis in other countries strongly indicate the need for continued careful surveillance.

A retrospective analysis of levels of antibody to hepatitis B surface antigen in 1419 health care workers was carried out to compare the efficacy of intramuscular and intradermal administration of plasma derived and recombinant hepatitis B vaccines. No significant difference was detected between the response to intradermal and intramuscular plasma derived vaccine. However of those who received intramuscular recombinant vaccine 81.6%, 13.8% and 4.7% were good (> 100 miu/ml). low (10–99 miu/ml) and non-responders (< 10 miu/ml) respectively. compared with 51.1%, 29.8% and 19.2% of the intradermal group (P > 0.0001). Low dose intradermal administration of recombinant vaccine did not produce satisfactory levels of antibody to hepatitis B surface antigen.

It has been suggested that individuals might be more readily colonized with bacteria that cause meningitis through enhanced binding of the bacteria to virusinfected epithelial cells. As respiratory syncytial virus (RSV) affects infants and children in the age group also susceptible to bacterial meningitis, we tested the hypothesis that infection of HEp-2 cells by RSV might enhance binding of Neisseria meningitidis or Haemophilus influenzae type b (Hib). Attachment of fluorescein-labelled bacteria to HEp-2 cells was measured by flow cytometry, and RSV-infected cells bound significantly more meningococci (P < 0·001) and Hib (P < 0·01) than uninfected cells. Although the isolates expressed different antigenic characteristics (3 meningococci and 5 Hib), all showed a similar pattern of binding. The results are discussed with reference to the methods used for detection of bacterial binding and to interactions that might explain the increased binding to RSV-infected cells.

The presence of pneumococcal capsular antigen (PCA) in the oropharynx was sought in subjects without respiratory tract infection. Saliva specimens from 239 subjects were analysed by counter-current immunoelectrophoresis using ‘Omni-serum’. 15.5% gave positive reactions but only 24% of positive samples were typable and therefore due to pneumococcal or pneumococcal-like antigens. Given that oropharyngeal production of antigens occurs we investigated whether PCA in expectorated sputum arose from oropharyngeal contamination. Sixteen patients with pneumococcal pneumonia, and with sputum positive for PCA, were investigated in detail. On the basis of serotyping and concentration the PCA in sputum was thought to arise from the lower respiratory tract in all cases. This was confirmed by a simple, novel approach involving the comparison of concentrations in concomitant samples of saliva and sputum. Thus while oropharyngeal production of antigens poses a potential diagnostic problem the latter approach can be used to exclude contamination.

The epidemic cycle of Chlamydia pneumoniae infection was examined in two areas in eastern Finland over a period of 15 years, 1972–87. The C. pneumoniae IgG antibody prevalence was determined with 5-year intervals in a random sample of the population aged 25–59 years. The total number of sera studied using immunofluorescence was 2387. In 1972 the antibody prevalence was 57% and it increased to 66% in 1977. Over the next 5 years the prevalence decreased to 44% in 1982, but by 1987 it had again increased to 59%. The temporal variation in prevalence was statistically significant (P < 0·001) and similar for both genders. Throughout the observation period the overall prevalence Mas 7–11% higher in men than in women (P < 0·01). The antibody prevalence increased with age, being the highest among the oldest study subjects of both genders. The periods of high and low prevalence alternated in an epidemic cycle (P < 0·001) of about 10 years