During a 4-month period during the summer of 1985, campylobacters were isolated from 338 (16·3%) of 2080 patients with acute diarrhoea attending the University Hospital of Infectious Diseases in Zagreb. Of these isolates 220 (64·1%) were Campylobacter jejuni and 118 (34·9%) were C. coli. The patients were drawn from three residential zones in and around Zagreb: inner city, peripheral city and rural. Incidences of campylobacter diarrhoea ranged from 71 per 100 000 per year in inner city residents to 99 per 100 000 per year in the rural residents. Most infections were in young children; the incidence in infants ranged from 800 to 2500 per 100 000 per year in the inner city and rural zones respectively. The isolation rate from faecal specimens of infants from the rural zone was 61%. The ratio of isolation rates in males and females (all ages) was 1·1:1, but in infants it was 0·7:1 and in patients over the age of 65 years it was 0·4:1. The incidence of C. coli in the rural zone was four times that in the inner city and twice that in the peripheral zone.

This survey shows that campylobacter infection in Zagreb has distinctive epidemiological features. The transmission of infection appears to be midway between that found in industrialized and developing countries, and there is an unexplained excess of C. coli infection.

We report an outbreak of serious infections with Serratia marcescens in patients on a neurosurgery ward. The epidemiological investigations undertaken are described. Features of outbreaks of infection with serratia and control measures are discussed.

The haemagglutinating ability of 141 isolates of Aeromonas spp. for human. horse and guinea-pig erythrocytes was examined. Although the majority of isolates (136/141) agglutinated human group O erythrocytes, all the eight possible patterns of agglutination were observed. Haemagglutination of human group O erythrocytes. but not horse or guinea-pig, was associated with the ability to agglutinate yeast cells (Saccharomyces) and with aggregation in a low concentration of ammonium sulphate. Haemagglutinating ability was further characterized by reactions in the presence of mannose, galactose or fucose. All the possible patterns of inhibition with individual sugars were observed, but haemagglutination of human group O erythrocytes not inhibited by mannose, galactose or fucose was more common among isolates from patients with diarrhoea, and isolates producing a Vero cell cytotoxin than would be expected by chance. This might represent a virulence factor.

One hundred and fifty-three water samples from rural Nicaragua were examined for the presence of faecal coliforms during both wet and dry periods. A linear model as fitted by analysis of covariance with the logarithm of the faecal coliform count as the dependant variable. As expected, traditional water sources were grossly contaminated at all times whereas piped water sources were much cleaner. Hand-dug protected wells had significantly higher levels of faecal contamination than unprotected riverside wells and springs during the dry season. The possible reasons for this unexpected finding are discussed. A close association between rainfall and faecal contamination was demonstrated but the effect of rainfall depended on the type of water source. An association between water quality and the size of the community served by the source was also detected. The finding that stored water was usually more contaminated than fresh water samples is consistent with the results from other studies. Since it is unusual for water quality to be inversely correlated wth accessibility, this study site would be suitable for investigating the relative importance of water-borne versus waterwashed transmission mechanisms in childhood diarrhoea.

Antisera were prepared in rabbits against seven well-characterized strains of Treponema hyodysenteriae of known serotype, and reacted in agarose gel double immunodiffusion tests (AGDP) with lipopolysaccharide (LPS) extracted from 18 Western Australian isolates of the organism. Eight isolates were provisionally typed by this method, but sera raised against one ‘typed’ and two ‘untypable’ local isolates reacted in an unexpected fashion with LPS from other local and type strains. Serum raised against the ‘typed’ local isolate reached with LPS from other previously untyped local isolates: this indicated the presence of more than one major LPS antigen amongst certain local isolates, and was confirmed by cross-absorption of sera. Sera raised against apparently untypable local isolates reacted with LPS from certain type organisms, thus suggesting the presence of complex antigenic relationships between LPS antigens.

The serotyping system for T. hyodysenteriae which was proposed by Baum &Joens (1979) uses unabsorbed antisera and is made unworkable by these observations. Instead we propose placing organisms which share common LPS antigens into serogroups A to E, members of which are defined by their reactivity with unabsorbed sera raised against a type organism for the group. We suggest strains B78, WAI, B169, Al and WA6 respectively as being the most suitable type organisms for the five serogroups identified so far. Isolates possessing additional unique LPS antigens can be regarded as serotypes within the serogroup. However the serotype of an isolate can only be established if antiserum is prepared against it, and this serum continues to react homologously after cross-absorption with bacteria from other serotypes within the serogroup.

Sinks in a new long-stay hospital (LSH) were cultured weekly during 4 consecutive months to evaluate the microbial profile before and after occupancy of the hospital. From the elderly patients admitted to the patient care rooms oral and rectal specimens were collected to examine the contribution of the patients' flora to the sink contamination. Isolates were typed biochemically, serologically and by susceptibility pattern. Before occupancy Gram-negative bacilli were not isolated. Once the elderly patients, who were highly colonized on admission, occupied their rooms identical strains gradually contaminated the sinks. Escherichia coli, Klebsiella, Pseudomonas and Acinetobacter species were the major correlating strains. The mean concentration of the correlating isolates was higher in throat and intestines compared to the mean concentration of the non- correlating strains. These strains seem to have a greater chance to be shed and then transferred via the hands of personnel to sinks. This resport shows that the major route of environmental contamination is from patient carriers to sinks, and not the reverse way.

During 1986 and 1987, faecal samples from patients with haemorrhagie colitis (HC) or haemolytic-uraemic syndrome (HUS) were examined for evidence of infection by verotoxin-producing Escherichia coli (VTEC). During the 2-year period VTEC infections were found in 31 (78%) of 40 patients initially presenting with HC, and in 5 (63%) of 8 patients initially presenting with HUS, VTEC were found in only 2 (0·9%) of 229 age and sex matched control patients with acute non-bloody diarrhoea. All but one VTEC belonged to E. coli serogroup O 157. During 1987 this serogroup was isolated from 2 (1%) of 207 samples of faeces taken from cattle arriving at a Sheffield abattoir, indicating a possible source of these infections for man. We are unaware of previous reports of isolation of this organism from cattle in England.

Erythromycin resistance amongst group A streptococci (GAS) in Great Britain is a relatively rare occurrence and outbreaks have been sporadically reported. Over an 8-month period in 1986 ten associated cases occurred in the town of Bridgwater in Somerset. Isolates were group A, type M4 and resistant to erythromycin (MIC 8 mg/l) but sensitive to lincomycin and clindamycin. Erythromycin resistance was transferable from all isolates to a group A recipient strain. No plasmid DNA could be detected in the original isolates or transconjugants.

Necrobacillosis is caused by Fusobacterium necrophorum (FN), but other organisms are often present in the lesions. Their possible role was studied in experiments made with a virulent FN strain which, by itself, produced fatal necrobacillosis in mice provided that large doses ( > 106 organisms, subcutaneously) were given. Mice were inoculated subcutaneously with FN suspended in sub-lethal doses (0·1 ml) of undiluted or diluted broth cultures of other bacteria. Undiluted culture of a strain of Escherichia coli reduced the infective dose of FX to < 10 organisms: in the necrobacillosis lesions that developed, fusobacteria greatly outnumbered E. coli. A heat-killed preparation or sterile filtrate of E. coli culture had little if any effect on FN. Citrobacter freundii and comparativelv small numbers of Corynebacterium (Actinomyces) pyogenes produced effects similar to that of E. coli. An α-haemolvtic streptococcus. Pseudomonas aeruginosa. Bacteroides fragilis and Fusobacterium nudeatum also enhanced the infectivity of FN. though less strikingly than E. coli. FN increased the persistence in vivo of the α-haemolytic streptococcus and B. fragilis, and enabled the latter to multiply profusely.

Chickens which had been inoculated orally with a nalidixic acid-resistant strain of Salmonella typhimurium were reared on a diet containing different concentrations of avoparcin in an attempt to explain the variation in response to commercial levels of this antibiotic oberved by different workers. In one experiment small increases in faecal excretion of the inoculated salmonella occurred at 2·5 and 5·0 mg kg−1, with greater increases between 7·5 and 20 mg kg−1 In a second experiment there was a significant increase in excretion at 7'5 mg kg−1 and in a third experiment in which generally higher excretion rates were detected in all groups, significant increases were observed at 10 and 12·5 mg kg−1 only. In addition avoparcin significantly increased the faecal excretion of S. cholerae-suis, S. dublin and S. arizonae, serotypes not usually associated with poultry-derived food-poisoning in the United Kingdom. It did not increase faecal excretion of S. pullorum. Avoparcin at 10 mg kg−1 appeared to have little effect on the normal intestinal flora of S. typhimurium infected chickens despite the fact that when tested in vitro individual organisms were susceptible to this drug concentration. At 100 mg kg 1 viable counts of intestinal enterococci and Gramnegative anaerobic bacteria were considerably reduced while those of S. typhimurium and Escherichia coli increased. Antibiotic activity due to avoparcin was detectable in the alimentary tract and there was some increase in concentration of the antibiotic in the more distal regions.

A total of 1012 milk filters collected from 498 dairy farms in south-western Ontario during three study periods (December 1985–March 1986) were tested for the presence of verocytotoxin-producing Escherichia coli (VTEC). VTEC were detected and isolated using a Vero cell assay. Supernatants from 20 of the milk filter cultures had verocytotoxic activity and 7 VTEC strains were isolated from these positive samples. The prevalence of VTEC in the samples in each of the three study periods were 0·44, 0·65 and 0·99% respectively. All seven VTEC strains isolated were sensitive to commonly used antimicrobial agents. The serotypes of these strains were O 26.H11, O43.H2, O 153.H25, O ?. H8, O ?. H19, O ?.non-motile, and Orough. H19. Two of these serotypes (O 153. H25 and O 26.H11) have previously been associated with disease in humans.

Five pigs were treated orally with norfloxacin for 5 consecutive days in two well-separated periods. This was done to determine the lowest dose required to free the pigs of Enterobacteriaceae. In the first period of the study, the animals were treated with 400 mg per day while in the second treatment 800 mg norfloxacin was given. Daily faecal culturing indicated that the faeces became free of Enterobacteriaceae in 3–5 days when treated with 400 mg/day, while all animals were found negative on culturing after 3 days of treatment with 800 mg/day. Investigation of the concentration of norfloxacin in the faeces revealed that a substantial fraction of the dose was either absorbed or inactivated by faecal substances. An in vitro study in faeces confirmed that a substantial part, some 75% of the dose, may have been inactivated by intestinal contents. This finding helps to explain the much lower concentration of 120 mg norfloxacin per kg of faeces in the pig in comparison with the almost tenfold higher concentration reported to develop in man during treatment with an identical dose.

Differentiation of Salmonella enteritidis by plasmid profile typing has been compared to differentiation by phage typing. Examination of the type strains of the 27 S. enteritidis phage types showed that only 11 profile patterns could be identified. Moreover, two profile patterns were found in 15 of the type strains, including those of the two most common phage types in Britain, types 4 and 8. On this basis, plasmid profile typing is not as sensitive as phage typing for the primary subdivision of S. enteritidis.

When differentiation of 534 strains of the 27 phage types was attempted using plasmid profiles, variation in pattern suitable for epidemiologieal subdivision was found in 13 phage types and there were 9 profile patterns in strains of phage type 4. Plasmid profile typing can, therefore, be regarded as an effective adjunct to phage typing for the subdivision of S. enteritidis

Mice, birds (chicks, quail) and fish (rudd, goldfish) killed shortly after receiving 1300–2000 spores of Clostridium botulinum per os were incubated, usually at 23 °C for 7 days. A 10% (w/v) homogenate of each rotting carcass was then prepared, sterilized by membrane filtration, and assayed for toxin.

In mouse carcasses a type C strain of C. botulinum usually produced > 2 × 105 mouse intraperitoneal LD/g; in fish carcasses it usually produced less - often much less - than 2 × 104 LD/g. Avian carcasses appeared to be intermediate between those of mice and fish in their ability to support toxigenesis. A type E strain of C. botulinum, unlike type C. produced toxin equally well in fish and mouse carrion, usually at a concentration of between 2 × 104 and 2 × 105 LD/g.

Faraday Base represents a small isolated community producing its own domestic water by desalination of sea water. During the Antarctic winter of 1986 (April to October), regular bacteriological examination of the water supply and surrounding sea took place. Samples were collected and examined every 2 weeks by the methods described in the Department of Health and Social Security Report No. 71, on the Bacteriological Examination of Drinking Water Supplies (DHSS, 1982), for membrane filtration and colony counting. The results of these examinations are presented in this paper. The results obtained suggest that water of good bacteriological quality was produced by the desalination plant, but some samples from the distribution system contained coliforms or presumptive Escherichia coli in small numbers. The possible reasons for this low-level contamination are discussed. No cases of gastroenteritis occurred on the base during this time.

The spread of two strains of Staphylococcus aureus with high level resistance to mupirocin is described. The resistance proved to be easily transferred to other S. aureus strains by filter mating experiments and on the skin of mice. No plasmid band corresponding to the resistance could be demonstrated by agarose gel electrophoresis or by caesium chloride gradient centrifugation but cleavage of ‘chromosomal’ DNA from resistant recipients showed bright bands of DNA absent from sensitive controls.

Among the 81 cultures of Salmonella typhimurium of phage type 141 examined, 72 had been isolated from Sheffield incidents in 1984–5 and 9 were Scottish isolates from 1986–7. All of these cultures from diverse sources belonged to primary biotype 31; 79 were of full biotype 31beg and 2 anaerogenic cultures were of full biotype 31begj. This is the first known occasion on which an epidemic strain of S. typhimurium of phage type/biotype 141/31beg has been implicated in outbreaks of human or animal infection in the UK. Because previous epidemic strains of S. typhimurium of phage type 141 in the UK belonged to biotypes 1f and 9f which are phylogenetically unrelated to biotype 31beg, the likely origin of this most recent epidemic S. typhimurium strain of phage type/biotype 141/31beg is discussed.

A mathematical model has been developed which allows estimation of the epidemiological and economic effects of different tetanus vaccination strategies. The model was used to simulate the epidemiology of tetanus in italy from 1955 to 1982, and then applied to a district of Tuscany by utilizing data obtained from a seroepidemiological survey carried out in the same area. For this district we simulated vaccination programmes designed to reach, within 1 or 10 years, coverages of 60 or 90% of the population aged over 10 years who had not been exposed to the neonatal vaccination programme. The most effective strategy, from both the epidemiological and economic point of view, seems to be 90% coverage reached in 1 year's time. Benefits would be increased by improving the reliability of vaccinal anamnesis.

The degree of protection conferred by vaccinated dams on infant mice against colonization by Campylobacter jejuni depended on the bacterial strain, preparation, and route of administration of the vaccine. In some instances of homologous protection, serum bactericidal titres correlated well with protection. However, boiled C. jejuni vaccine, which was non-protective, also elicited a strong bactericidal antibody response. Conversely, bactericidal activity could not be demonstrated against strains capable of cross-protection. There was a good correlation between high campylobacter-specific IgG response and bactericidal activity.

Six hundred and thirteen fresh diarrhoeal faeces were inoculated on Skirrow blood agar (SK), on Preston blood free agar (PBF), and in Campy-thioglycolate broth (CT). After 24 h of storage at 4 °C, specimens were again inoculated on SK and PBF, and in Campylobacter enrichment broth (CEB). CT tubes were placed overnight at 4 °C. Plates and CEB tubes were incubated at 43 °C in microaerophilic conditions. A total of 68 specimens was positive for campylobacter on direct plating. Sixty-four of them were also recovered after subculturing from CT, and only 51 from CEB. Delayed inoculation of plates after storage of samples at 4 °C yielded 57 isolates. The storage of faeces at 4 °C for 24 h significantly reduces the number of campylobacter isolates. When samples are not plated immediately we recommend inoculating a CT tube maintained at 4 °C overnight as a holding medium.