In this study we examined 730 faecal samples of offal (mainly liver), mince-meat and sausage meat collected from abattoirs and retail butchers' shops for campylobacters. Campylobacter jejuni or C. coli were isolated from 30·6, 10·5 and 6% of sheep, cattle and pig offal samples respectively. Specimens collected from abattoirs were, in general, more often contaminated than material obtained from retail butchers' shops. Only 1·4% of minced meats and sausage meats contained campylobacters. Most isolates (89·5%) were C. jejuni biotype 1 (Skirrow & Benjamin, 1980) of serotypes 1 and 2 (Penner & Hennessy, 1980). This study shows that animal offal is frequently contaminated with C. jejuni of biotypes and scrotypes commonly isolated from human beings with campylobacter enteritis.

A panel of 10 monoclonal antibodies was used to subgroup 326 strains of Legionella pneumophila serogroup 1. All but two strains could be classified into three major subgroups named after their representative strains Pontiac 1, Olda and Bellingham 1. Of the 50 isolates from patients, 44 representing 32 separate incidents were of the Pontiac subgroup. This subgroup was also found in 16 of 18 buildings epidomiologically associated with Legionnaires' Disease. In contrast, strains of the Olda subgroup predominated in buildings where no infections had occurred. In 9 of the 11 incidents where isolates were available from at least one patient as well as from the suspected environmental source, the monoclonal antibody reaction patterns of strains from patients were identical to those of one or more of their environmental counterparts.

Mice of strain TO, in groups of ten, were inoculated intravaginally with Mycoplasma pulmonis organisms. Seven mice became infected after inoculation of organisms with strong haemadsorptive capacity, four after inoculation of organisms with diminished adsorptive capacity following ten passes in medium, and none after inoculation of apparently non-adsorbing organisms which had been passed 50 times. There appeared to be a correlation, therefore, between the ability to infect and the cytadsorptive capacity of the organisms. There was only a minimal vaginal polymorphonuclear leucocyte (PMNL) response in the infected mice and most of them had ceased to be infected by 35–42 days. In contrast, mice treated with progesterone had enhanced infections; all those given strongly haemadsorbing organisms, and organisms passed ten times, became infected and remained so for at least 42 days. Furthermore, at least ten fold more organisms were recovered from progesterone-treated than from untreated mice, and the PMNL response was much greater. Most of the progesterone-treated mice given organisms passed 50 times did not become infected, but some did, and the organisms recovered from them were fully cytadsorptive. It is postulated that a few cytadsorbing organisms in this inoculum were induced to infect under the enhancing effect of progesterone.

The biochemical and biological properties of the flagella of Campylobacter jejuni have been investigated using two variants selected from a flagellate, motile clinical isolate (strain 81116): a flagellate, non-motile variant (SF-1) and an aflagellate variant (SF-2). Phenotypic and biochemical analysis of the strains and amino acid analysis of the isolated flagella suggest that the variants differed from the wild-type strain only in the absence of flagella and/or motility. The aflagellato variant poorly colonized the gastrointestinal tract of infant mice but the flagellate, non-motile variant colonized the mice as successfully as the wild-type strain.35S-labelled organisms were used to investigate the attachment of the variants to human epithelial cell monolayers in vitro. The flagellate, non-motile strain attached more efficiently to the cells than the wild-type strain or the aflagellate strain. Differences in attachment suggest that an adhesin is intimately associated with flagella of C jejuniand that active flagella mediate only a tenuous association with host cells. This adhesin attached most efficiently to cells of intestinal epithelial origin and was not specifically inhibited by various sugars.

A survey of Campylobacter species in the faeces or rectal contents of domestic animals was carried out using direct and enrichment culture methods. Campylobacters were isolated from 259 (31 %) of 846 faecal specimens. The highest isolation rate was found in pigs (66%); lower rates were found in cattle (24%) and sheep (22%). In pigs all the isolates were C. coli, in sheep and cattle about 75% were C. jejuni. Only five isolations of C. fetus suhsip. fetus were made, all from cattle. More pigs with diarrhoea had C. coli in their faeces than healthy pigs (77% vs 47 %), but such a clear difference in isolation rate between sick and healthy animals was not seen in cattle or sheep.

The enrichment method increased the total isolation rate of C. jejuni and C. coli by 33%, but for cattle specimens it increased it by 69% (from 6·5% to 21%). However, the enrichment method failed to detect 16% of positive specimens (mainly C. coli), so direct and enrichment methods should be used for the culture of campylobacters from animal faeces. The results show that cattle, sheep and pigs constitute a large potential source of campylobacter infection for man.

The isolation and description of Bacillus coli commune by Escherich a hundred years ago marked the start of a series of scientific investigations which have led to some of the most important discoveries in microbial pathogenicity and genetics that have been made since that time. It is not difficult to find the reasons why so much effort has been concentrated on this organism. Escherichia coli is present in the gut of all warm-blooded animals generally forming the predominant aerobic flora; it is of medical and veterinary importance being responsible for a variety of infections in the human and animal populations and it has provided a useful tool for geneticists.

Salmonella carriage in 5888 gulls sampled by cloacal lavage was found to be 7·8%. Marked geographical and seasonal differences in carriage rates were found. These differences appeared to be associated with human population density and seasonal differences in the reported incidence of human salmoncllosis. The maximum duration of salmonella excretion in 17 laboratory-maintained gulls was 4 days and the number of salmonellae excreted was never more than 170 per gram of faeces. On the basis of this study it is suggested that gulls are not important factors in the actiology of human salmonellosis.

Among 622 cultures of Salmonella montevideo, 27 biotypes belonging to two biogroups were recognized. One biogroup (10di) was predominant in all animals in Scotland but only in sheep in England and Wales. The other (biogroup 2d) was responsible for almost all human, cattle and poultry infection in England and Wales, but only 24% of human infection in Scotland.

The effect of hypochlorite concentration on Mycoplasma mycoides ssp. mycoides viability was tested under a variety of conditions. The experimental variables employed included chlorine-cell contact time, chlorine concentration, carrier system and organic loading. Initial populations of 106 c.f.u./ml were killed (no survivors in 1 ml) by hypoehlorite solution containing 25 p.p.m. available chlorine in 15 s in the absence of organic load and 50 p.p.m. available chlorine in 5 min in the presence of 1% protein. Higher concentrations of hypochlorite were required to disinfect a porous carrier system in the absence or presence of protein. The results are in contrast to previous reports that M. bovis is killed only by high hypochlorito concentrations.

Ever since Escherich (1885) first isolated the organism now known as Escherichia coli from the stools of infants, medical microbiologists have been faced with the problem of distinguishing between those strains capable of causing diarrhoea and those that are harmless gut commensals. Epidemiological investigations were greatly facilitated by the description by Kauffmann (1947) of a serotyping scheme for E. coli, and Taylor (1961) later reported that 17 0 serogroups of E. coli had been implicated as possible causes of epidemic infantile enteritis. These infantile enteropathogenic E. coli (EPEC), having been discovered by epidemiological studies using serotyping, belonged by definition to a restricted range of serogroups. More recently it was shown that other E. coli strains may produce enterotoxins, and these enterotoxigenic E. coli (ETEC) usually belong to particular serogroups which are different from those associated with EPEC. E. coli strains belonging to a third range of serogroups may cause an illness resembling shigella dysentery, and these may be regarded as entero-invasive E. coli (EIEC). E. coli strains that cause diarrhoea may therefore be considered as three groups, as follows.

When Theodor Escherich (1885a, b) first described Escherichia coli he looked on it as a saprophytic organism. Soon several investigators found that colibacteria could be isolated from intestinal infections and from many infections outside the intestine, like urinary tract infections (UTI), cholecystitis, wound infections, meningitis, septicaemia, pulmonary infections, and many more. Uhlenhuth (1897) showed that coli strains from pathological processes were more pathogenic in animal experiments than strains isolated from the normal intestine. Smith (1927), who examined strains from white scours in calves, showed that spontaneous acapsular mutants could be obtained from certain colibacteria, and that such mutants were less virulent when injected intra-peritoneally into guinea-pigs.

Aztreonam, temocillin, gentamicin and tobramycin were studied for their effect on the human faecal flora in vitro and for their usefulness for selective decontamination (SD) of the gastrointestinal tract. The sensitivities of the obligately anaerobic flora and the Gram-negative facultatively anaerobic bacteria were determined and the ratio was expressed as SD factor. Tho high SD factor of the flora from most subjects for aztreonam and tobramycin indicates that the drugs are useful for SD in contrast to temocillin and gentamicin. Binding to and subsequent release of tobramycin from faeces are presumed to facilitate the maintenance of adequate concentrations in the intestine despite the discontinuous intake.

Two strains of Legionella pneumophila (LP) serogroup I, of differing virulence, were examined in terms of numbers of viable organisms in tissues, pyrexia and mortality following aerosol infection. The Corby strain was the more virulent, with Pyrexia and deaths of guinea-pigs 3 to 6 days after infection. This strain multiplied very rapidly in the lungs to reach a peak of 5 × 1011 viable organisms/lung. Organisms were present in the blood, liver, spleen and kidney. The Philadelphia-1 strain (NCTC 11192) was unable to replicate in the lung and was cleared between 14 and 21 days after infection. Pyrexia was not observed. No guinea-pigs died and viable LP was not found in any organ other than the lung.

Lung lavages on aerosol infected animals were performed and the virulent Corby strain was found to be mainly intracellular. The avirulent Philadelphia-1 strain was found predominantly in the extracellular location. There were approximately 10 times the number of viable virulent LP in the lung macrophage fraction than in the lung PMNL fraction. In comparison, there were approximately equal numbers of the viable avirulent strain in the macrophages and the PMNL. Experimental evidence suggests that the macrophage preferentially supports the growth of the virulent Corby strain compared with the PMNL. The avirulent strain on the other hand appears to be destroyed by both the macrophages and the PMNL.

It has been known for a considerable time that Escherichia coli, although a normal inhabitant of the intestinal tract, can also be associated with a variety of pathological conditions in man, farm animals and poultry.

When Escherich (1885) isolated from the faeces of a newborn baby an organism which is now accepted as E. coli, he considered it to be a harmless saprophyte. Laruelle (1889) was the first to suggest the possible pathogenicity of this organism, while Jensen (1893) showed that it was the cause of white scour in calves. The development of reliable serological methods facilitated the differentiation of strains and numerous workers have demonstrated an association between certain serological types of E. coli and various disease conditions in animals. Enteric diseases in young animals are an important cause of mortality and economic loss to the farming community.

Pour thousand two hundred and forty six samples of retail processed food were examined for the presence of Escherichia coli. Overall 12% of samples contained this organism, cakes and confectionery being more frequently contaminated (28%) than meat and meat based products (9%). Contamination was more frequent in the summer months than in the colder weather and 27% of the contaminated foods contained > 103E. coli/g. E. coli from meat and meat based products were more commonly resistant to one or more antibiotics (14%) than were confectionery strains (1%). The significance of these findings in relation to the E. coli population of the human bowel is discussed.

A series of 925 clinical isolates of klebsiella was examined by serological and biochemical typing. To perform serological typing (capsular swelling) 77 capsular antisera were prepared, tested against the type strains and grouped in 13 pools. With this serotyping method 80% of the cultures were typable and 63 distinct types could be recognized.

All strains were typable biochemically by means of the numerical coding system of the API-20E system supplemented by digits derived from 15 additional conventional biochemical tests. With the API-20E system 24 different biotypes could be distinguished whereas the combination of API-20E and the 15 additional tests produced 93 biotypes. Maximum discrimination of strains was achieved by the combination of serological and biochemical typing (256 bioserotypes). The reproducibility, typability and discriminating power of the biotyping system was not inferior to serotyping. For epidemiological purposes biotyping can replace serotyping of Klebsiella species, especially in laboratories less well equipped.

It is possible to differentiate isolates of Escherichia coli using a number of techniques including the determination of the serotype, biotype and phage type and the profiles for resistance to antibacterial agents and toxic chemicals, intracellular enzymes, outer membrane proteins and plasmids and the production of enterotoxin and colicines. These methods have been used principally for the study of pathogenic E. coli and plasmid-mediated drug resistance. However they can also be used successfully for ecological purposes and the application of several of these techniques for the study of the ecology of E. coli in healthy young animals including man is described.

The numbers and serotypes of Clostridium perfringens present in the faeces of three groups of hospital patients and young healthy laboratory workers were examined in studies lasting between 10 and 13 weeks.

In one hospital some long-stay geriatric patients carried relatively high numbers of C. perfringens (> 107/g) most of the time and it was not unusual in any one week for the majority of these patients to carry the same serotype(s). However, the numbers of C. perfringens in the faeces of young long-stay patients in the same hospital were in the range of 103–104/g and carriage of common serotypes was not observed. These results were similar to the findings with the young laboratory workers.

This investigation indicates that two of the laboratory criteria often used in the investigation of C. perfringens food poisoning, i.e. faecal counts of ≥ 105C. perfringens/g and patients carrying the same serological type need to be interpreted with caution with suspected outbreaks involving some groups of geriatric long-stay hospital patients.