The bacteriological investigation of an outbreak of Legionnaires' disease in Glasgow Royal Infirmary affecting 16 patients is described. Most of the patients had been treated in high-dependency areas on two floors of the hospital supplied by the same two air-conditioned ventilation systems. The source of infection was traced to contamination of a cooling tower from which a plume of spray discharged into the intake vents of the two ventilation systems. Rubber grommets within the cooling tower probably provided a nidus of infection there. The control and management of the outbreak are discussed: a policy of frankness about the course and progress of the investigations was adopted and helped to allay anxiety on the part of both staff and media.

The plasmid pSLT is a cryptic plasmid of 60 megadaltons (Md) present in Salmonella typhimurium LT2. We present evidence that it has a characteristic fingerprint when digested with the restriction enzymes PstI and SmaI. Among a representative collection of S. typhimurium isolates it was present in 67% of strains and was widely distributed amongst different phage types (DT) with the exception of DT10 and U285. Furthermore, its prevalence among veterinary isolates was significantly higher than among human isolates. It was not found among any of the 96 strains representative of other salmonella serotypes currently prevalent and thus appears to be serotype-specific.

The history and epidemiology of bovine tuberculosis in cattle herds in East Sussex are described. Since 1960, following the compulsory eradication scheme for tuberculosis, the incidence of herd infection has been low. The epidemiological features of herd infection have been sporadic incidents, with only small numbers of cattle becoming infected in the majority of incidents. There was no evidence of endemic Mycobacterium bovis infection in the cattle population in East Sussex in recent years, but a low risk of infection for cattle on the South Downs, from badgers, was apparent.

Following the disclosure of Mycobacterium bovis infection in badgers in East Sussex in 1976, badgers have been examined from and around farms on which cattle have become infected, but with no other attributable source of infection. These farms are confined to the downland of the south-west of the county and M. bovis has been confirmed in badger populations utilising their land. The available evidence indicates that M. bovis infection in badgers is also confined to this area. A detailed study in one area on the South Downs suggested that M. bovis is endemic in the badger population and therefore presents a continued risk for cattle occupying the area.

The distribution of plasmids was studied in a representative collection of salmonella strains which comprised 98 Salmonella typhimurium and 96 other serotypes. Plasmids were detected in 72% of strains (mean 1·3 plasmids/strain) and individual strains harboured between 0 and 7 plasmids. They were more common among S. typhimurium than other serotypes (incidence 92 and 53%; mean 1·9 and 0·8 plasmids/strain respectively). Although a higher proportion of S. typhimurium (33%) were antibiotic-resistant compared to other serotypes (14%) the evidence presented indicated that R-plasmids were not responsible for the difference observed in the number and distribution of plasmids in these strains. These results were discussed in comparison with similar studies of Escherichia coli and other enteric genera.

A survey was undertaken of the occurrence, serotype, antimicrobial sensitivity and plasmid content of members of the tribe Proteeae in the environment of two calf-rearing units in the county of Avon in South West England. Examples of the following species were found: Proteus mirabilis, Prot. vulgaris, Prot. vulgaris Biogroup 2, Morganella morganii, Providencia stuartii, Prov. alcalifaciens and Prov. rettgeri. A wide range of sero types was found, many having been previously reported from nosocomial isolates. A total of 15% of isolates carried plasmids; six pairs of isolates were identified which had identical sero typesbut different patterns of plasmid carriage. The antimicrobial sensitivity of the isolates was generally similar to isolates of Proteeae from humans. Although no truly aminoglycosideresistantisolates were found, some isolates of Prov. stuartii and Prov. rettgeri had MIC's higher than the other isolates to gentamicin and netilmicin, suggesting the presence of lowlevels of the enzyme AAC 2′. The study demonstrates that there is a considerable diversityof species and types of Proteeae associated with calves and their environment. It seems likely that a potential cause of colonization of the human gut by Proteeae is the consumption of meat.

Restriction enzyme fingerprints were generated from purified plasmid DNA from 324 clinical isolates that belonged to 7 enterobacterial genera and 88 single plasmids in Escherichia coli K12 according to the following strategy.

Purified plasmid DNA was digested with PstI. The number of fragments detected in a 0·8 agarose gel was used to determine which 2 of 6 restriction enzymes including Pstl was most likely to provide a fingerprint comprising sufficient fragments to ensure specificity but sufficiently few to allow easy visual assessment and minimize coincidental matching. When PstI produced > 20 fragments, Eco RI and HindIII were used; when PstI generated < 6 fragments Bsp 1286 and AvaII were used and SmaI was employed when between 6 and 20 fragments were obtained from PstI digests. Using a minimum of 12 fragments from a combination of 2 enzymes as the criterion for characterizing a strain/plasmid, satisfactory 2-enzyme fingerprints were obtained from 87% of the strains and plasmids studied using PstI and no more than two additional enzymes per strain. Of the remaining 54 strains, 51 harboured only small plasmids (< 10 kb) and 3 produced satisfactory fingerprints when digested with a fourth enzyme.

Following epidemiological and ecological studies of a defined badger population in an area of East Sussex, removal of all badgers by cage trapping was attempted. Trapping was incomplete due to the activities of protesters. Forty-seven badgers were caught from the eight social groups. All badgers were examined clinically and samples of faeces, urine and tracheal aspirate were taken, together with swabs from any bite wounds, for bacteriological examinations. Forty-five animals were skin tested using whole killed cells of Mycobacterium bovis strain AN5, bovine PPD Weybridge and new human tuberculin. Skin test results were recorded after 24 and 72 h. All badgers were killed and subjected to a post-mortem and bacteriological examination.

M. bovis was detected in 10 (21·3%) badgers at post-mortem and in 2 badgers from clinical samples. Four social groups were infected. Positive skin test results were recorded at 72 h with bovine PPD (2 μg and 20 μg/ml), strain AN 5 (1 mg/ml) and human tuberculin (2 μg/ml), but not with human tuberculin at 20 μg/ml. Histological sections of the skin test reactions showed the cellular types typical of delayed-type hypersensitivity. The skin test reactions observed were neither sensitive nor specific enough to be of practical value.

In Salmonella typhimurium phage type 204c isolated in Britain, gentamicin resistance is specified by plasmids of the I1 compatibility group which also confer resistance to apramycin. These plasmids have been subdivided into three types within the I1 group on the basis of their antibiotic resistance specificity, their ability to produce colicin Ib and their restriction enzyme digest fragmentation patterns. All three have been identified in strains from cattle, but as yet only two types have been found in strains from humans.

It is suggested that the use of apramyein in animal husbandry is responsible for the appearance of gentamicin resistance in multiresistant strains of phage type 204 c, a phage type already epidemic in bovine animals and with an increasing incidence in humans.

Plasmid profiles have been established for 68 isolates of Staphylococcus aureus from 13 episodes of epidemic spread in hospital wards between 1958 and 1962. Despite the original lack of care in preservation of strains the profiles give, in general, the same epidemiological patterns as were established originally on the basis of phage type, antibiotic sensitivity, ward and date of isolation.

The carriage of Staphylococcus aureus was studied in a group of 28 men living in a totally isolated environment for a year. Initially, nasal, axillary and perineal swabs were taken at weekly intervals, but from week 24 throat swabs were taken from known nasal carriers. Several attempts were made during the study to eradicate S. aureus. Eight subjects consistently carried their own phage type throughout the study, despite the application of antibacterial agents. In three subjects strains were isolated late in the study of a phage type which had either not been isolated before in this study, or had not been found for a prolonged period. Nine of the 12 nasal carriers also yielded S. aureus from the throat. It is apparent that following attempted eradication, S. aureus may seem to disappear, only to reappear some time later; ‘eradication’ in this case would be an erroneous appellation.

A detailed investigation of the possible role of wild mammals, other than badgers, in the maintenance of Mycobacterium bovis in an area on the South Downs of East Sussex was carried out over 3 years. Estimates of population sizes were made where possible and minimum sample sizes were selected to be 95 % certain of including at least one infected animal if the prevalence was at least 5 %. Samples of wild mammals were taken from populations which had the highest potential direct or indirect contact rate with known infected badgers. M. bovis was not isolated from any of the 15 species of wild mammals.

It was concluded that badgers are able to maintain M. bovis in an area independently of other species, and that in the area studied other species were not a source of infection for the cattle herds.

The impact of three current types of preoperative large bowel preparation on the microbial flora and the colonization resistance (CR) was investigated in 15 volunteers. In the first group a whole gut irrigation was performed without administration of antibiotics (group WGI). In the second group 0·5 g/1 metronidazole and 1 g/1 neomycin was added to the irrigation fluid (group WGI + AB). A whole gut irrigation with prior oral administration of 1 l mannitol 10% was performed in the third group. The antibiotic prophylaxis in this group consisted of two doses of 80 mg gentamiein i.v. and 500 mg metronidazole orally 24 h after lavage (group Mann + AB). One hour after the mechanical cleansing procedure was finished all volunteers were orally contaminated with one dose of an Escherichia coli test strain. The aerobic faccal reduction due to the cleansing procedure was 2–3 logs, while for the anaerobes it was 4–5 logs. The anaerobic flora in group WGI recovered within 24 h, while the aerobes showed a transient ‘overgrowth‘ for the period of 2 days. The overgrowth of aerobes in group WGI + AB was observed for more than a week and the total numbers of aerobes started gradually to decline after the anaerobic flora had reached pretreatment levels at day three or four. Despite the normal numbers of anaerobes present 24 h after treatment, overgrowth of E. coli was seen in the group Mann + AB, probably due to residual mannitol left in the intestinal tract. The test strain of E. coli was excreted for a period of 1 week by the volunteers in the groups WGI and Mann + AB, but it was isolated for more than 10 weeks in the group WGI + AB. It is thought that all three methods of preoperative large bowel preparation decreased the CR of the gastrointestinal tract because of a disturbance of the interaction between aerobic and anaerobic microorganisms and alterations of the colonic wall. The anaerobic microflora. however, appeared to be primarily responsible for the maintenance of the CR. Antimicrobial prophylaxis should consist of a high dose, short term. systemic antibiotic regimen, not only because an adequate serum level of an appropriate drug at the time of operation substantially decreases the incidence of postoperative septic complications but also because a systemic regimen scarcely influences the CR of the gastrointestinal tract. β-Aspartylglycine appeared to be a specific but not very sensitive marker for decreased CR.

In the Netherlands, case histories of 160 patients aged more than 1 month, with meningitis due to bacteria other than Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae were reviewed in order to look for associations between the bacteriological data and the course of disease.

The incidence of such cases was about 0·8/100000/year. Escherichia coli and Listeria monocytogenes each accounted for about 15% of the cases. The case-fatality rate was 18·8% (Gram-negative bacteria, 25%; Gram-positives, 15%) and sequelae occurred in 13·3% of the surviving patients (14 and 13% Gram-negative and Gram-positive, respectively). Hearing loss was the most prevalent sequela (50%). Predisposing factors were present in 70% of patients (69 and 71% respectively), especially in meningitis due to enteric Gram-negative bacteria (except for salmonella) and due to staphylococci.

Surveillance is important because the incidence of meningitis due to these micro-organisms is likely to increase and because the problems in antibiotic treatment have not yet been solved.

Since the aminoglycoside antibiotic apramycin was licensed for veterinary use in 1980, all isolates of Escherichia coli and salmonellas received at the Central Veterinary Laboratory have been monitored for resistance to apramycin and the related antibiotic gentamicin. During the period 1982–4, the incidence of resistance in E. coli to apramycin increased from 0·6% in 1982 to 2·6% in 1984. In salmonellas the incidence of resistance to apramycin increased from 0·1% in 1982 to 1·4% in 1984. Resistance to both apramycin and gentamicin was detected in six different salmonella serotypes, although an isolate of Salmonella thompsonfrom poultry was resistant to gentamicin but not apramycin. Most of the cultures were isolated from pigs, although the incidence of apramycin resistance in S. typhimurium (DT 204C) from calves has shown a recent dramatic increase. All the isolates with one exception produced the enzyme aminoglycoside 3-N-acetyltransferase IV (ACC(3)IV). The resistance was transferable by conjugation in most of the strains examined, and the plasmids specifying the resistance have been found to belong to a number of different incompatibility groups. Plasmids from three E. coli strains were compatible with all the reference plasmids and belonged to a previously undescribed group which was investigated further.

It is suggested that bacteria from humans should be examined for resistance to apramycin and gentamicin to determine the possibility of the antibiotic-resistance bacteria, and their genes, spreading from animals to humans.

Four strains of Legionella pneumophila of different virulence as identified by ability to produce pneumonia and death in guinea-pigs infected by a fine-particle aerosol were examined for factors which may intracellularly influence virulence. Possible bactericidal mechanisms possessed by alveolar phagocytes were examined. A relationship could be established between resistance to H2O2, catalase activity and virulence amongst the strains.

Virulent strains resisted the bactericidal activity generated by the xanthine oxidase system; avirulent strains did not. Incorporation of various specific inhibitors of the xanthine oxidase system indicated that the main bactericidal activities were associated with the production of H2O2 and hydroxyl radicals ('OH).

All strains of L. pneumophila were susceptible to the bactericidal activity generated by the myeloperoxidase-H202-halide system, confirming earlier observations that polymorphonuclear neutrophil leucocytes (PMNLS) are able to kill both virulent and avirulent strains of L. pneumophila.

In an outbreak of gastroenteritis on board a cruise ship 251 passengers and 51 crew were affected and consulted the ship's surgeon during a 14-day period. There was a significant association between consumption of cabin tap water and reported illness in passengers. Enterotoxigenic Escherichia coli were isolated from passengers and crew and coliforms were found in the main water storage tank. Contamination of inadequately chlorinated water by sewage was the most likely source of infection.

A low level of reported illness and late recognition of the outbreak delayed investigation of what was probably the latest in a series of outbreaks of gastrointestinal illness on board this ship. There is a need for a national surveillance programme which would monitor the extent of illness on board passenger cruise ships as well as a standard approach to the action taken when levels of reported illness rise above a defined level.

An enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of brucella-specific IgG, IgM and IgA in 173 patients with acute brucellosis, 22 patients with chronic brucellosis and in 281 controls consisting of 98 patients with other infectious etiologies, 20 patients with non-infectious diseases and 163 normal healthy adults. The ELISA results were compared with culture findings, the results of slide agglutination tests with Brucella melitensis (M), B. abortus (A) and Ross Bengal (RB) antigens, and of tube and microagglutination tests. Brucella cultures were positive in 53 and 5% of patients with acute and chronic brucellosis respectively. The slide agglutination tests with A, M, A plus M and RB antigens were positive in 42, 44, 51 and 98% of patients with acute brucellosis and in 23, 27, 27 and 64% of patients with chronic brucellosis. There was no significant difference in the results between the tube and microagglutination tests regardless of the type of antigen used. At a titre of ≫ 80 or ≫ 160 these tests were positive in 98% and 92% of patients with acute brucellosis and 60 and 40% of patients with chronic brucellosis. The brucella culture and agglutination tests were negative for all the controls.

Brucella ELISA immunoglobulins (Ig) were detected in some individuals in the control groups but the majority of these had titres of ≫ 100 for IgG, IgM, and IgA. However, patients with brucellosis had significantly higher ELISA titres in all classes of Ig than controls but the sensitivity and specificity within each Ig class varied with the titre considered. At a titre of ≫ 1600 the brucella IgG had a sensitivity and specificity of 98% for patients with acute or chronic brucellosis; this decreased with lower reciprocal titres. The brucella IgM titre of ≫ 400 had a sensitivity of 98% and a specificity of 98% for patients with acute brucellosis. However, in patients with chronic brucellosis the brucella IgM was very low. The brucella IgA titre of ≫ 200 showed a sensitivity of 98% and a specificity of 99% for patients with either acute or chronic brucellosis. This study indicates that brucella ELISA is a rapid, sensitive and specific assay, provides a profile of Ig classes in the diagnosis of acute and chronic brucellosis, is useful for mass screening and could be considered the method of choice for the serological diagnosis of brucellosis.

A 1-year prospective study of nosocomial bacteraemia was performed at Hvidovre Hospital with special reference to frequency, focus of infection and prognosis. All patients were examined clinically in order to confirm the bacteraemia. In total, 98 hospital-acquired bacteraemias were observed, giving an incidence rate of 0·28%. Bacteraemia due to Escherichia coli, Staphylococcus aureus and Staphylococcus epidermidis predominated. The overall mortality was 38%; 65% of the patients with S. aureus bacteraemia died, 25% due to the bacteraemia. The most common types of infection were urinary tract infections and intravenous catheter infections. Fifty-five of the bacteraemias were caused by foreign bodies, mostly urinary catheters and intravenous catheters, and in 14 cases the focus was unknown. The patient population was severely ill patients. We conclude that nosocomial bacteraemia occurs specially in severely ill patients often preceded by indwelling urinary or intravenous catheters. The patients seldom die due to the bacteraemia, but they die with concomitant bacteraemia.

Two dairy herds, situated on a sewage farm, were monitored for the presence of salmonellas following outbreaks of Salmonella dublin infection. In addition an S. dublin control scheme, which involved examination of adult animals and calf vaccination, was instigated.

During the period 1975–84, 12 salmonella serotypes and 10 phage types of S. typhimurium were isolated from the cattle and their environment although their presence was seldom associated with disease. Two adult S. dublin excreters were detected but it was concluded that none of the tests employed to examine the adult animals was sensitive enough. The prevalence of disease in the calves was low and although vaccination may have been beneficial it did not eradicate S. dublin infection. Thus S. dublin persisted in adults and calves during the 8-year period but its presence was seldom associated with disease. The results are discussed with regards the disease risk to animals from the agricultural use of sewage sludge and the public health aspects.