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.

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.

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.

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.

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.

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.

In a prospective survey carried out over 9 months in 1984 in the Department of Bacteriology, Belfast City Hospital, Campylobacter jejuni was isolated from 24 out of 1200 faecal specimens (2%) from patients with acute diarrhoea. This isolation rate is much lower than that from other parts of mainland Britain which report an isolation rate of between 8 and 15%. It is difficult to explain this large discrepancy but the limited availability of unpasteurized milk and the generally worse summer here (fewer barbecues, picnics) may be some reasons to explain this low incidence in N. Ireland.

Amounts of Mycobacterium tuberculosis antibodies were determined in sera from patients with either active or inactive tuberculosis and in healthy subjects by an immunoenzymatic assay in which whole BCG cells attached covalently to polystyrene disks were used as antigen. Statistically significant differences (P < 0·005) were found both between the active and inactive tuberculosis groups and between the active group and healthy controls. No significant differences were found between the inactive group and controls. Since this procedure is efficient (91%) and can be used in areas which lack laboratory equipment, it appears promising for individual serodiagnosis and for epidemiological surveys.

The survival of Escherichia coli in an aerosol was studied at several temperatures and over a range of relative humidities using a Henderson apparatus.

Death occurred in two phases, the first lasting approximately 1 min; in the second the number of viable microorganisms declined exponentially. E. coli was robust and remained viable for many hours. Death was most rapid at low humidities (< 50% r.h.) at 15 and 30 °C, with half-lives of 14 and 3 min respectively. In humid conditions the half-lives were much longer, approximately 83 and 14 min respectively.

Based on this work, preliminary recommendations for the climate of livestock buildings can now be given to control the airborne spread of E. coli.

A survey on the bacteriological quality of both drinking water and flavoured drinks from coin-operated vending machines is reported. Forty-four per cent of 25 drinking water samples examined contained coliforms and 84% had viable counts of greater than 1000 organisms ml at 30 °C. Thirty-one flavoured drinks were examined; 6% contained coliforms and 39% had total counts greater than 1000 organisms ml. It is suggested that the D.H.S.S. code of practice on coin-operated vending machines is not being followed. It is also suggested that drinking water alone should not be dispensed from such machines.

The apparent reduction in the incidence of subsequent joint sepsis and of re-operation without evidence of infection during the course of a prospective study was an artifact of the analysis method.

A total of 571 swine sera collected at an abattoir in the city of Obihiro, Hokkaido during the period February–November 1984 were tested for antibody against human (H1N1) influenza virus strains. A high prevalence of antibody was observed for only 3 months from April to June in that year, in 81/180 sera (45·0%) to A/USSR/92/77 strain and in 50/180 sera (27·8%) to a current epidemic strain (A/Hokkaido/1/84). Some cross-reactions were observed between the A/USSR/92/77 and A/Hokkaido/1/84 antibodies (r = 0·75). Only minor relationships were noted between the A/New Jersey/8/76 (swine type H1N1) and A/USSR/92/77 (r = 0·35) or A/Hokkaido/1/84 (r = 0·51) antibodies. Absorption of sera positive for antibody to the A/Hokkaido/1/84 strain with the homologous virus strain removed all detectable antibodies, while the absorption of the sera with the A/New Jersey/8/76 strain produced incomplete absorption in one half of the sera tested. These resultsstrongly suggest that the swine became infected with a human H1N1 virus as piglets during an epidemic of influenza which occurred in the human population during January and February 1984.

A four-component solid-phase capture enzyme immunoassay was set up to test for serum IgM antibody to respiratory syncytial (RS) virus and was compared with immunofluorescence assay (IFA).

A total of 128 young children with acute respiratory infections were studied. Thirty-six were shown to be RS virus-positive by the detection of RS virus in nasopharyngeal secretions and 92 were RS virus-negative. A serum specimen was collected after admission to the hospital (days 0–4) and a further specimen was obtained during days 10–14. Out of 36 RS virus-positive patients, 28 (77·7%) were found to be positive for IgM by both capture-ELISA and IFA. Out of 92 RS virus-negative patients 5 (5·4%) were IgM-positive. Four false-positive results were obtained by IFA due to the presence of rheumatoid factor.

The capture-ELISA was shown to be a reliable technique in detecting specific IgM antibody to RS virus.