In 1882 Robert Koch reported the isolation of tuberkelbazillen from human and bovine sources. Sixteen years later, Theobald Smith (1898) demonstrated that strains of Koch's tubercle bacilli from these two hosts differed in cell morphology, cultural characteristics and virulence in rabbits. He did not believe that these variants were limited to the hosts from which they were isolated nor that the differences resulted from adaptations to a given host. Indeed, he remarked that ‘It might be better to omit the host designation of such varieties in order to anticipate assumptions that they are necessarily limited to the host whose name they bear.’ Nevertheless, heedless of his own misgivings he termed them the ‘human’ and ‘bovine’ types.

Forty-one clinical isolates of Legionella pneumophila from sporadic cases of legionella pneumonia were collected from laboratories throughout the United Kingdom and were compared with 300 routine environmental isolates using two panels of monoclonal antibodies, covering serogroups 1–10. Eighty-five per cent of the clinical isolates belonged to the subgroup Pontiac of serogroup 1, whilst only 13% of the environmental isolates did. Approximately half of the clinical isolates tested came from patients with a recent history of foreign travel, mainly to southern Europe.

A comparison was made between membrane filtration and centrifugation for the isolation of Legionella pneumophila from seeded water samples. Using samples of varying concentration, the optimum speed and time of centrifugation were determined and the relationship between the number of organisms present in the water and the proportion recovered was examined. Following this, sequential routine environmental waters were filtered and centrifuged in parallel.

Centrifugation and filtration using nitrocellulose filters were found to be comparable. The optimum speed and time of centrifugation was approximately 6000 g for 10 min. There was a constant proportion of viable organisms recovered irrespective of the concentration in the unspun samples.

A food-borne outbreak of sore throat caused by Lancefield group G β-haemolytic streptococci and involving 50 persons occurred in May 1983 in an Israeli military camp. All of the patients available for clinical examination had sore throat and difficulty in swallowing. Exudative tonsillitis occurred in 46% of the patients and the body temperature was above 37·5 °C in 81%. The pattern of attack was uniform over the base and 37 became ill during the night and morning of the 5 May. Thirty-two (84%) of the throat cultures taken from 37 patients grew group G β-haemolytic streptococci. Eight of 29 contacts were positive for group G β-haemolytic streptococci and 6 of the 28 foodhandlers examined had positive cultures of the same group. The organism was also isolated from one food sample. The epidemiological and laboratory investigations indicated that a food handler, a convalescent carrier of group G streptococci, might have been the source of infection. Assumptions on the potential of non-group A streptococci to cause epidemics are discussed.

Group L, β-haemolytic streptococci can cause infection in dogs, pigs, cattle and sheep but there have been very few reports in man. In studies of skin infection in meat handlers we cultured group L streptococci from clinically infected wounds, impetigo and paronychia of 15 patients involved in the slaughter and processing of chickens and pigs. Staphylococcus aureus was also present in eight (53%) of the lesions. At least five other infections with group L streptococci in meat and animal handlers are known to have occurred in other parts of England in recent years, and brief details are given.

A simple impression-plate technique has been used to investigate the survival of four thermophilic campylobacter strains applied to fingertips. Campylobacters suspended in 0·1% peptone water and dried on the fingertips survived for different periods of time ranging from < 1 to ≧ 4 min. However, campylobacters suspended in chicken liquor or blood survived for much longer periods. The most resilient organism was Campylobacter jejuni NCTC 11392 which, when suspended in 50% horse blood, survived for an hour. Suspensions containing 106–107 organisms prepared in 50% blood and dried on to fingertips were removed by thorough hand washing with either soap and water or water alone followed by drying on paper towels, but persisted on wet hands. The organisms were also eliminated by wiping the hands with a tissue saturated with 70% isopropyl alcohol for 15 sec.

The distribution of serogroups of thermophilic campylobacters isolated in Israel from human patients (2421 isolates), chicken (942), turkeys (158), cattle (398), wild birds (234) and other sources, was studied.

Among the human isolates, 74 ROG-serogroups were identified. The six most commonly isolated of these (1,18; 11; 12; 8,23; 4 and 5,39) were found frequently in chickens. Only four common serogroups in man were also common in cattle, three in turkeys and two in wild birds.

Two common serogroups in man (1,18 and 5,39) were prevalent all over the country, while others were regionally distributed. When the prevalence of different serogroups in Israel was compared to that in Canada, some groups were common to both countries and others were common in only one or the other.

Campylobacter jejuni accounted for 86·7% to 92·1% of the isolates from man, chickens, turkeys, cattle and most of the wild birds. C. coli was found in 34·4% of isolates from cattle egrets and in 70·5% of those from pigs.

A molecular epidemiological study was carried out on 60 Salmonella dublin isolates identified at the Southern Italy Enterobacteriaceae Center between 1971 and 1985. These included 23 isolates from children with diarrhoea in Palermo obtained during 1984.

All isolates from the outbreak of gastroenteritis in children were resistant to chloramphenicol and streptomycin and harboured two plasmids of 50 MDa and 3 MDa molecular weight, whereas the majority of the isolates identified before 1984 were susceptible to these antibiotics and carried only a 50 MDa molecular weight plasmid. Four S. dublin strains successively identified from cattle (Palermo, Foggia, Portici) and from a child (Palermo) were shown to possess similar antibiotic resistance patterns and plasmid profiles to S. dublin isolates from the outbreak of gastroenteritis in children.

The 50 MDa plasmid was shown to be associated with virulence in mice, while it was not possible to assign any genetic function to the 3 MDa plasmid.

For many years phage typing has proved invaluable in epidemiological studies on Salmonella typhi, S. paratyphi A and B, S. typhimurium and a few other serotypes. A phage-typing scheme for S. enteritidis is described. This scheme to date differentiates 27 types using 10 typing phages.

Salmonella was the most frequent bacterial pathogen isolated from patients with acute diarrhoea in Hong Kong. In Queen Mary Hospital, the major hospital on Hong Kong Island, 94·7% of salmonellae isolated from faecal specimens from patients during the period 1973–82 belonged to the gastroenteric group, while 5·3% belonged to the enteric fever group. Amongst the gastroenteric group, 68 salmonella serotypes were identified, with Salmonella derby, S. typhimurium and S. analum being the predominant ones. Three outbreaks caused by S. johannesburg, S. worthington and S. wandsworth were detected.

Of S. typhimurium, 61·0% were resistant to multiple antibiotics and belonged to four major phage types: 193, 22, 138 and U288. The majority (96·8%) of S. johannesburg strains which caused a widespread epidemic were multiply-resistant. Multiple antibiotic resistance was rarely observed in most other gastroenteric salmonellae.

S. typhi was the commonest of the enteric fever group isolated from the blood of patients. Nineteen phage types were identified; E1 being the commonest (18·5%) while 21% were nontypable. Many of these isolated were resistant to streptomycin or sulphadiazine, but none were resistant to ampicillin, chloramphenicol or trimethoprim.

Plasmids present in multiply-resistant salmonella strains including Salmonella typhimurium, S. johannesburg, S. wandsworth, S. derby, S. newport, S. london and S. choleraesuis causing diarrhoea in patients in Queen Mary Hospital in Hong Kong from 1973–82 were studied. In multiply-resistant S. typhimurium, plasmids belonging to groups F1me, H1, or H2 and plasmids encoding trimethoprim-resistance which were compatible with standard plasmids of testable incompatibility groups were detected. In S. johannesburg, both the ASTCKSu- and ASCKSu- resistant strains which were predominant in two consecutive periods of an outbreak were found to harbour the same plasmid which belonged to the incompatibility group F1me. S. wandsworth strains isolated from a hospital outbreak in 1980 harboured an identical R-plasmid belonging to group N. A few strains of the other salmonellae showing resistance to multiple antibiotics were found to harbour R-plasmids belonging to groups H1, H2 and F1me. The only salmonella of the enteric fever group resistant to ampicillin, chloramphenicol and trimethoprim was an S. paratyphi B strain. The resistances were encoded on a plasmid of an unknown incompatibility group. The occurrence and distribution of plasmids in these salmonellae isolated within the 10-year period are discussed.

Samples of blended mutton tissue in small polyvinyl chloride sachets were incubated in water baths for different times and at varying temperatures. The temperature of each bath was recorded accurately throughout each experiment. Using equations previously derived for the lag and generation times of coliform organisms in blended mutton tissue, the expected increases of these bacteria were calculated from the time/temperature recordings. These were compared with the data obtained from plate counts made on the tissue samples in the sachets before and after incubation. The studies were done with a strain of Escherichia coli, one of Salmonella lyphimurium and the coliform organisms naturally present on sheep carcasses processed in a commercial abattoir. The calculated growth agreed closely with that measured. Therefore, if mutton, after overnight chilling, is warmed again to temperatures within the growth range of these bacteria, the possible increases in the numbers of cells present can be calculated directly from time and temperature measurements.

The implications for the present codes of practice in abattoirs are discussed.

An estimate for the source of coagulase-negative staphylococci in blood cultures is presented and its use illustrated in two populations. The method estimates the probability that a positive blood culture is positive due to contamination and the probability of it being positive due to bacteraemia. The effect of changes in efficiency of the blood culture technique on these estimates is demonstrated. One of the illustrative populations consists of 537 sample pairs from 273 patients, taken after open-heart surgery in 1978–80. The other consists of 500 consecutive sample pairs taken in one of two hospitals in 1983–4.

Two hundred and one strains of Staphylococcus aureus isolated from in-patients and out-patients were examined for sensitivity to antibiotics, heavy-metal ions and ethidium bromide and for phage-typing pattern.

Heavy-metal ion resistance was less frequent than reported in previous studies and was as frequent in penicillinase non-producing as producing strains. ‘Methicillin-resistant’ strains were resistance to ethidium bromide and mercury. Resistance to heavy-metal ions, including cadmium, may bo becoming less common amongst clinical isolates of S. aureus.

Two waves of vomiting and/or diarrhoea affected approximately 215 of the 715 passengers on a Caribbean cruise ship. The outbreak was independently associated with eating cream-filled pastries at two separate meals. Staphylococcus aureus phage type 85/+ was isolated from cases and pastry cooks, but not from controls. This is the first well-documented outbreak of staphylococcal food poisoning on a cruise ship.

Two enrichment methods were compared for their ability to recover Clostridium difficile from stool samples. One method used selective enrichment in an antibiotic-containing broth followed by detection with a latex particle agglutination (LPA) reagent. The other used enrichment in a non-selective broth following treatment of the specimen with alcohol. With clinical specimens enrichment culture was significantly more successful at detecting C. difficile than direct plating. Alcohol shock enrichment was twice as effective as direct culture, while selective broth enrichment was three times more effective. The use of LPA for screening selective enrichment broths for C. difficile should prove a cost-effective measure as only positive broths (about 20%) require subculture for confirmation.

Tropical ulcer is a disease found most commonly in the tropics, although the disease is not confined to those areas. Young children are affected most frequently and the disease is thought to be a polymicrobial infection with fusobacteria, aerobic microorganisms and spirochaetes each playing a role. The fusobacteria have been reported on smears but have not been cultured thus far. We report the isolation and culture of these organisms from 46 ulcers and have also demonstrated the same organisms in skin biopsies from these lesions.

Among 30 strains of leptospires isolated from samples of sewage taken before and during treatment at two sewage plants in England, only one appeared to belong to Leptospira interrogans, the species that comprises the leptospires that are pathogenic to man and animals. That strain, Compton 746, was isolated from settled sewage, before treatment at a treatment plant that deals mainly with human sewage. It was shown serologically to belong to serogroup Tarassovi and appears to represent a new serovar that has been named mogdeni after the name of the sewage plant, Mogden, from which it was isolated.

A cross-sectional serological survey of domestic animals in West Malaysia revealed that 25·5% of the animals examined had agglutinating antibodies to one or more antigens belonging to Leptospira interrogans. Significant prevalence of infection was observed in cattle (40·5%), buffaloes (31%) and pigs (16%). The Sejroe serogroup was shown to be the principal one involved in cattle and buffaloes, and to a lesser extent the Tarassovi and Pomona serogroups. Evidence of infection in domestic animals by strains bearing the other seven antigens appeared insignificant and was indicative of sporadic infection. A majority of the large (semi-intensive) cattle and buffalo farms demonstrated a high prevalence of leptospiral infection. In both species of domestic animals mentioned above, the prevalence of infection was significantly higher (P = 0·01) in the semi-intensive farms than in the smallholdings. Amongst cattle, the droughtmasters had the highest prevalence whilst the Kedah-Kelantan (an indigenous breed) had the lowest prevalence of leptospiral infection. In general, the temperate breeds of cattle had a significantly (P = 0·01) higher prevalence of infection than local breeds. Leptospiral infection in goats and sheep was shown to be sporadic, and the Pomona serogroup was the principal leptospiral serogroup involved in these small ruminants. The prevalence of infection in pigs was observed to decline during the study period, and it is suspected that pigs in West Malaysia are the maintenance host for serovar pomona whilst cattle are the maintenance host for serovar hardjo. Overall, it appears that domestic animals in Malaysia will play a bigger role in the epidemiology of leptospiral infection with the advent of sophisticated farming.

The one-point MCA method is very simple to perform nnd useful as a screening test in diagnosing leptospirosis in routine clinical laboratories.

The kit, sensitized with six serovars occurring in Japan, was also useful in detecting serum antibodies of patients with leptospirosis in China.