Nocardial taxonomy, like that of other actinomyeete genera, has undergone all the viscissitudes of doubt associated with years of inadequate and sometimes inappropriate methodology. This is reflected by the great expansion of species names allocated to the genus over the first two thirds of this century (Buchanan, Holt & Lessel, 1966), followed by the contraction achieved in the list of approved bacterial names in 1980 (Skerman, McGowan & Sneath, 1980). Created by Trevisan in 1889 for five species, modern taxonomists would now allocate some 20 species to the genus, including only one of Trevisan's original five species (Table 1). As an actinomycetc genus Nocardia has suffered from two particular disadvantages. First in having an apparently distinctive nocardioform morphology on the basis of which organisms were referred to this genus long after crude morphology lost its importance in many other genera. Second in having an unfortunate type species, Nocardia farcinica, with no really well accredited type strain.

It is nearly 100 years since Noeard described bovine farcy, a granulomatous disease of cattle characterized by abscesses, sinus tracts and pulmonary disease (Nocard, 1888). This was the first disease due to Nocardia species described. Since that time our knowledge of the role of the nocardiae in human veterinary diseases, of the epidemiology of these diseases, and their diagnosis and treatment, has enlarged rapidly. This paper attempts to give an overview of our current understanding of these diseases.

This paper describes the relationship between different forms of nocardia infection involving the skin. The best recognized of these conditions are systemic nocardiosis and actinomycetoma due to Nocardia spp. in which the organisms are present in either filamentous or grain form respectively. Attention is drawn to evidence for the existence of a primary cutaneous form of nocardiosis which follows inoculation and in which the organisms grow in filamentous phase. It is not clear whether such cases can progress to mycetoma formation if left untreated, or whether other factors are involved. The clinical and laboratory features of these different clinical varieties of nocardia infection are discussed.

There are three commonly recognized species of Nocardia that cause disease in a large variety of animals including humans. In the United States, pulmonary or systemic nocardiosis in humans caused by N. asteroides is most frequently diagnosed. It should be noted that N. brasiliensis can cause nocardiosis also. In Central and South America mycetomas induced by N. brasiliensis appear to be more prevalent even though N. asteroides can be seen in this type of infection. Sporadic cases of both mycetoma and nocardiosis caused by N. caviae have been reported. These three species of Nocardia appear to be present in the soils of most countries; but N. asteroides is more frequently isolated in the temperate climates whereas N. brasiliensis predominates in the tropical and subtropical regions of the world. No specific geographic distribution has been noted with N. caviae. Infections involving these three species of bacteria are, therefore, worldwide in occurrence. Even though nocardial infections in both humans and animals were recognized as early as 1888, traditionally, they have been considered rare in frequency as compared to many other infectious diseases. This is a perception that probably is not accurate. During the past twenty years, greater diagnostic awareness combined with more intensive medical and veterinary surveillance have resulted in significantly increased recognition of disease caused by these aerobic actinomycetes.

Cefotaxime, a cephalosporin drug, has been shown to be active in vitro against nocardiae, a finding confirmed in this study. Pharmacokinetic studies were performed in mice to define regimens which provided peak serum levels comparable to that achieved in man with currently used doses. These regimens were shown to be effective with only short courses of therapy of rapidly progressive and highly lethal N. asteroides infection, produced by pulmonary challenge of mice. This suggests the possible utility of this drug in human nocardiosis.

The proportion of salmonella carriers among town-nesting herring gulls increased significantly from 2·1% in 1975–6 to 8·4% in 1979. The range of serotypes carried by herring gulls was similar to that causing infection in man, and it is likely that the gulls ingest these serotypes when feeding at untreated sewage outfalls on the coast. This is supported by the proportion of salmonella carriers being higher among first-year birds (9·7%) than among older birds (2·0%), as it is known that higher proportions of immature herring gulls feed on the coast. Herring gulls carrying salmonellas appeared healthy at the time of capture and at a later date it was assumed that they were not themselves infected. However, their habit of congregating in large numbers on reservoirs and rubbish tips and also at resting sites on farmland often far from feeding and roosting areas, multiplies thejpollution problem and increases the potential health hazard for both man and farm stock. Herring gulls feed at a variety of sites and fly many miles from food source to food source and from feeding areas to the roost. Thus, even within the same day, there is the possibility of the transfer of salmonellas over a much wider area than previously considered.

This paper presents evidence for the involvement of herring gulls (Larus argentatus) as vectors in the recent outbreaks of Salmonella montevideo in sheep and cattle in Scotland and suggests that the transfer can take place over considerable distances. The breeding area in Scotland of herring gulls which overwinter in N.E. England is remarkably similar to the geographical distribution of the outbreaks. This pattern, together with the feeding behaviour of herring gulls on farmland, the presence of S. montevideo in herring gulls just before their departure from the wintering area and the timing of the return just before the peak of outbreaks are all circumstantial evidence implicating this gull in the outbreaks. The rapid return of these gulls to their breeding areas means that S. montevideo can be transported long distances in one day and raises the possibility that the original source of S. montevideo could have been in N. E. England rather than in Scotland.

Two enrichment broths (Preston and Roman & Doyle's) and four solid media (Preston, Skirrow's, Butzler's and Blaser's) were compared to determine their relative efficiencies in recovering campylobacters from 389 freshly voided seagull faeces, 276 of which were found to contain campylobacters by one or more of the procedures used.

A combination of enrichment in Preston medium followed by plating on to Preston agar gave the highest number of isolates (263). Enrichment in fluid media was shown to be an important part of the technique, as only 85 (30·8 %) of the 276 isolations were made as a result of direct plating.

Very little difference was seen between the two forms of enrichment (P > 0·5) but of the four selective media, Butzler's was significantly less efficient than any of the other three (P < 0·01), because it failed to grow more than a few strains of Campylobacter coli and the NARTC group, which together made up nearly two-thirds of the total number of Campylobacter spp. isolated.

The development of Rappaport's enrichment medium and elevated temperature incubation as methods of salmonella isolation is traced. The recent recording of a merger of the two techniques by means of Rappaport–Vassiliadis medium is noted (RV medium).

In Cardiff, we have found an earlier modification of Rappaport's enrichment (R25) by Vassiliadis to be efficient in salmonella recovery from environment samples. The current study compares the two media using sewage polluted natural water as test material. Under the conditions of experiment, R25 was more successful in salmonella isolation than RV, although the latter medium inhibited competitive organisms better.

R25 is a convenient enrichment broth for routine use. In combination with pre-enrichment it allows the use of a loop for subculture rather than a pipette. This increases safe manipulation. It also produces a high proportion of positive isolations at the 24 h subculture time in contrast to other enrichment broths. For these reasons it forms an integral part of salmonella isolation methodology in our laboratory.

In two surveys of three commercial abattoirs a minimal apparatus method for making bacterial counts, the ‘loop-tile’ method, detected the same trends in bacterial numbers on beef carcasses as the ISO reference method applied to the same samples. Both methods showed the carcasses from one abattoir, that with an export licence, to carry consistently higher numbers of bacteria, and one of the four sites sampled on each carcass to be consistently dirtier than the other three.

The growth of an enterotoxin A producing strain of Staphylococcus aureus in corned beef was investigated. In the inoculated 6 lb. canned product the bacteria spread throughout the meat and attained high numbers. The rate of spread of the organisms was related to the temperature and length of storage of the cans and the numbers of bacteria inoculated. Cans which had been stored for more than four months showed high counts of the bacteria throughout the meat. It was noted that with the long term contaminated product counts of S. aureus on some selective media may give falsely low results.

Numbers of S. aureus on meat inoculated by handling after removal from the can were initially extremely variable. More uniform distribution and higher counts were attained only if the meat was exposed for some hours at ambient temperature or above. The significance of the results to the investigation of outbreaks of food poisoning suspected of being associated with canned corned beef is discussed.

The incidence of Staphylococcus aureus on turkeys sampled at various stages of processing and further-processing was determined on four occasions at each of three different processing plants. For freshly-slaughtered birds, counts from neck skin varied from plant to plant over the range < 102 to > 105/g but in all cases the corresponding counts obtained from carcasses sampled after chilling rarely exceeded 103/g and the same was true for samples of mechanically recovered meat (MRM), the final raw product examined.

Despite the limited susceptibility of isolates from the different factories to typing by means of either standard human or poultry bacteriophages (55–94% untypable), evidence was obtained with the aid of biotyping for the presence of both human and animal-derived strains. However, some biotypes isolated from MRM were not detected at earlier stages of processing.

At one processing plant, an ‘indigenous’ type of S. aureus was clearly demonstrated. It occurred in high numbers in the defeathering machines (up to 105/swab), was found on carcasses at all subsequent stages of processing over the survey period and was shown to survive routine cleaning and disinfection procedures. Isolates of this type produced unusually large amounts of extracellular ‘slime’ in artificial culture.

Two of the three processing plants yielded isolates which were enterotoxigenic. Of 55 strains from Plant 1, 60% produced enterotoxin C and all were of the ‘indigenous’ type. In the case of Plant 2, only two type D-and one type F-producing strain were found.

Resistance of faecal Escherichia coli to ampicillin, tetracycline, sulphamethoxazole and gentamicin was studied in patients admitted to seven different departments in two hospitals. The resistance to ampicillin, tetracycline and sulphamethoxazole in the seven patient groups was 27–57%, 26–56% and 35–63%, respectively. Resistance to gentamicin was found in only one department. An E. coli flora predominantly resistant to ampicillin, tetracycline or sulphamethoxazole (> 50% of the E. coli strains in a faecal sample resistant) was found in 10–38%, 4–30% and 21–35% of the samples. A cross-sectional study focusing on the influence of the use of antimicrobial agents on the occurrence of resistant strains revealed a positive correlation between the annual turnover of broad-spectrum penicillins in various departments and the occurrence of predominantly ampicillin-resistant E. coli strains in these departments.

Faecal carriage of bacterial enteropathogens (enteropathogenic Escherichia coli (EPEC), shigellae and salmonellae) was studied in 265 individuals: 65 infants 3–6 months of age (50 bottle-fed and 15 breast-fed), 100 school-age children 8–10 years of age and 100 adults 21–50 years of age. All were apparently healthy, did not have gastrointestinal symptoms, had not received antibiotics in the proceding fortnight and were not malnourished. Enteropathogens were isolated from the faeces of 24 individuals (9–1%). Cultures were positive for enteropathogens in 20% of the infants (both breast- and bottle-fed), 8% of school-age children and 3% of the adults. EPEC was the most frequent isolate. Twelve different serotypes were detected. The highest recoveries were E. coli026: K60 and 044·K74. Shigella was detected only in school-age children (2%) and salmonella only in adults (1%). Campylobacter jejuni and Yersinia enterocolitica were studied only in the school-age children: there was one isolate of each of them. Most enteropathogens isolated were susceptible to the majority of the antibiotics tested. Only four E. coli strains, isolated from bottle-fed infants, could be considered multi-resistant. Two of the strains were E. coli 044: K74 and 020a020c: K61. The remainder were E. coli 0111: K58 and were capable of transferring some of their antibiotic resistance traits to a recipient strain.

Operating theatres are ventilated for a number of reasons, one of them being to keep numbers of airborne bacteria low at the operation wound. No matter how air is brought into the room, bacteria are removed by dilution rather than by air currents, because of turbulence caused by heat liberated by people and equipment and by movement in the room (Lidwell & Williams, 1960). With ventilation rates up to 20 air changes/hour, the dilution may differ at different sites in the room depending on the design of its ventilation system.

A method of quantifying the remanent antibacterial effect of a 2% triclosan preparation in detergent following three consecutive applications on the forearm of 20 volunteers over 2 h, is described with reference to its efficacy against a gentamicin-and multiply-resistant scrotype of Klebsiella aerogenes. The relevance of the residual activity of triclosan and other skin antiseptics in surgical and hygienic hand disinfection are discussed.

Appropriate skin care of newborns is performed partly to prevent infection but also for aesthetic and cleansing purposes. Skin care should involve cleansing with a non-toxic, non-abrasive neutral material. This study compared the relative risks and benefits of washing versus bathing with regard to bacterial colonization rate, clinical infection rate, body temperature and crying. The results confirm our clinical impression that bathing and washing routines do not differ with regard to signs of infection or other clinical complications. However, the washing routine does increase the babies heat loss and make them less comfortable.

In autumn 1978 an epidemic of respiratory disease resembling allergic alveolitis occurred in a small Finnish community. The disease was caused by repeated exposures to tap water aerosol. The raw water of the community and the sand filters of the purification system were heavily contaminated with mesophilic actinomycetes. Fourteen different strains of actinomycetes were isolated. Exposed persons with and without symptoms as well as unexposed control persons were tested for antibodies against five of these actinomycetes and against Enterobacter agglomerans. Both the exposed and the control persons had antibodies to actinomycetes but the exposed persons had antibodies against more actinomycete strains than the control persons. Precipitating antibodies against E. agglomerans were also found in control persons as well as in patients. There was a significant difference between the patients and the exposed healthy persons in bacterial agglutination tests with flagellar antigen of one E. agglomerans strain. However, the role of mesophilic actinomycetes and E. agglomerans in the aetiology of the disease could not be firmly established.