Genomic profiles were obtained for 76 strains of Campylobacter jejuni isolated from bacteraemic patients in England and Wales over the period 1981–94. Genotyping was performed by restriction fragment length polymorphism (RFLP) analysis using a random cloned DNA probe, and by ribotyping with a PCR-generated C. jejuni 16S ribosomal DNA probe. Phenotypic characterization was achieved by heat-stable (HS) and heat-labile (HL) serogrouping, and Preston phagetyping and biotyping. The blood isolates were genomically heterogenous, with 24 RFLP/16S profiles occurring within the 76 strains. Forty-four percent of isolates belonged to one of three RFLP/16S genotypes, reflecting the patterns seen in faecal isolates, except that genotypes usually associated with the HS 1 antigen were uncommon. The two most prevalent genotypes, characteristic of HS 2 and HS 4 strains, showed similarity by cluster analysis. Further evidence was seen of associations between phenotypic and genotypic characters within some HS serogroups. Chromosomal profiling by RFLP analysis does not indicate that particular genotypes have a predisposition to invade the bloodstream.

An anonymized point-prevalence survey of methicillin-resistant Staphylococcus aureus (MRSA) carriage was conducted amongst a stratified random sample of nursing home residents in Birmingham, UK, during 1994. Microbiological sampling from noses, fingers and the environment was undertaken. Information about potential risk factors for the acquisition of MRSA was gathered. MRSA was isolated from cultures of the nose or fingers of 33 of the 191 residents who took part in the study (17%) but only 1 of the 33 positive residents had a clinical infection. Although just 10 of the 87 environmental samples were MRSA positive, there was some environmental contamination in most homes. Risk factors for MRSA carriage were hospital admission within the last year (relative prevalence 2·09, 95% CI 1·13–3·88; P < 0·05) and surgical procedures within the last year (relative prevalence 4·02, 95% CI 2·18–7·43; P = 0·002). Phage-typing of the strains revealed similarities with those circulating in Birmingham hospitals. These findings suggest that the prevalence of MRSA in nursing homes in Birmingham was high, and that the strains may have originated in hospitals.

Thirty-five E. coli strains belonging to O-serogroups associated with enteroinvasive types of Escherichia coli (EIEC) isolated in Germany between 1989 and 1995 were investigated for invasivity-associated DNA sequences. Only 11 strains were positive for ipaH and thus confirmed as EIEC. All 11 EIEC isolates originated from human infections which were imported to Germany from Eastern Europe. EIEC O124 were most frequent and originated from asymptomatic Romanians arriving at Rostock, Germany in 1992 and 1993. In January 1993, EIEC O124 were isolated from faeces of a laboratory technician with diarrhoea working at the enteric pathogen department of the Institute of Hygiene in Rostock. By comparing her E. coli O124 isolate with recently imported O124 strains for Xba I restriction fragment length polymorphisms (RFLP) the probable source of infection could be determined. Four major RFLP patterns were found in the group of O124 strains. O124 strains with identical RFLP patterns were found in the group of O124 strains. O124 strains with identical RFLP patterns were isolated from people who were in close contact to each other.

Between 23 August and 15 December 1990 an epidemic of cholera affected Mozambican refugees in Malawi causing 1931 cases (attack rate=2·4%); 86% of patients had arrived in Malawi <3 months before illness onset. There were 68 deaths (case-fatality rate=3·5%); most deaths (63%) occurred within 24 h of hospital admission which may have indicated delayed presentation to health facilities and inadequate early rehydration. Mortality was higher in children <4 years old and febrile deaths may have been associated with prolonged IV use. Significant risk factors for illness (P<0·05) in two case-control studies included drinking river water (odds ratio [OR]=3·0); placing hands into stored household drinking water (OR=6·0); and among those without adequate firewood to reheat food, eating leftover cooked peas (OR=8·0). Toxigenic V. cholerae O1, serotype Inaba, was isolated from patients and stored household water. The rapidity with which newly arrived refugees became infected precluded effective use of a cholera vaccine to prevent cases unless vaccination had occurred immediately upon camp arrival. Improved access to treatment and care of paediatric patients, and increased use of oral rehydration therapy, could decrease mortality. Preventing future cholera outbreaks in Africa will depend on interrupting both waterborne and foodborne transmission of this pathogen.

Laboratory-based surveillance of invasive pneumococcal infections in adults in Finland from 1983 to 1992 identified 862 episodes of pneumococcal bacteraemia and 97 episodes of meningitis. The overall incidence of invasive pneumococcal infections was 9·1 per 100000 for all adults per year, but 27·1, 35·8, and 44·5 per 100000 in those aged 65 years or over, 75 years or over, and 85 years or over, respectively. Most (99·7%) of the pneumococcal strains were sensitive to penicillin. Ninety-five percent of the strains belonged to serogroups/types present in the 23-valent pneumococcal polysaccharide vaccine. Group/type distribution was different in patients aged 16–64 years compared to those 65 years or over (P < 0·001), in bacteraemia compared to meningitis (P < 0·001), and in the years 1983–7 compared to 1988–92 (P < 0·05).

Sixty-eight isolates of Campylobacter jejuni and C. coli isolated from patients with diarrhoea (n=630) and controls (n=220) at Tikur Anbassa Hospital, Addis Ababa, Ethiopia were serotyped on the basis of the heat-labile (HL) and the heat-stable (HS) antigens, by using 16 and 34 antisera, respectively, for the two methods. With the antisera against heat labile antigens, 89–3% of the C. jejuni and 75% of the C. coli were typable. The HL serotypes 1, 2, 3, 4, 5, 6 and 7 were the most common among the C. jejuni while HL serotypes 1 and 2 were dominant among the C. coli isolates. These serotypes accounted for 63·2% of all isolates. For the heat-stable antigens, 60% of the C. jejuni and 83·3% of the C. coli isolates were typable. The HS serotypes 1, 3, 8, 26 and 34 were most common among the C. jejuni, while serotypes 3 and 8 were dominant among C. coli isolates. This study shows that the most common HL and HS antigens among campylobacter isolates from Ethiopia correspond to the most frequent antigenic types from other parts of the world. A limited number of antisera were sufficient to identify the majority of the isolates.

An examination of salmonella isolates collected by the Scottish Agricultural College Veterinary Services Division from April 1994 to May 1995 was conducted to determine the extent to which Salmonella enterica serotype Typhimurium phage type 104 (DT104) occurred and to investigate the antimicrobial resistance patterns of isolates. Typhimurium DT104 was the predominant salmonella and was isolated from nine species of animal. All isolates of this phage type possessed resistance to at least one antimicrobial and 98% of the isolates were resistant to multiple antimicrobials with R-type ACTSp the predominant resistance pattern. Various other resistance patterns were identified and transferable resistance to the veterinary aminoglycoside antimicrobial apramycin was demonstrated in three strains. A retrospective study for gentamicin resistance in isolates from the Scottish Salmonella Reference Laboratory collection revealed a human isolate of Typhimurium DT104 resistant to gentamicin but sensitive to apramycin and a bovine isolate with apramycin and gentamicin resistance.

A dairy herd associated with Escherichia coli O157 infection in humans was studied for the 15 months following the outbreak to examine seasonal, age and management factors affecting faecal excretion of the organism and to determine the mode and frequency of milk contamination with the organism. Between May 1993 and July 1994, 28 visits were made to the farm to collect a total of 3593 rectal swabs from cows, heifers and calves and 329 milk samples. E. coli O157:H7 was isolated from 153 (4·3%) of 3593 bovine rectal swabs. The maximum prevalence at any one visit was 14% in lactating cows, 40% in non-lactating cows, 56% in calves and 68% in heifers. The prevalence in lactating cows, which was significantly lower than in the other groups, peaked during May–July 1993 and again briefly after the cattle were housed during November 1993 and then again during May 1994. Excretion rates of E. coli O157:H7 in lactating cows were highest during the first month after calving, falling during lactation and rising to another peak at 7 months postpartum. Between November 1993 and May 1994 there was no evidence of excretion in any group. Eighty-seven (74%) of the animals which excreted E. coli O157:H7 did so on only one occasion but 23 (32%) of 73 cows and heifers and 7 (16%) of 44 calves which excreted the organism did so on more than one occasion. E. coli O157:H7 was not isolated from milk taken from the bulk tank but it was isolated from individual milk samples (one milk jar and one fore-milk) from two animals previously shown to be faecal excretors of the organism. All isolates of E. coli O157:H7 obtained were of the same phage type, toxin genotype and plasmid profile.

Group B streptococci (GBS) were isolated from bovine bulk milk and from vaginas and throats of antenatal and postnatal women using TKT and rapid GBS media. Sixty-three of 529 (12%) bovine bulk milk samples, 9 of 48 (19%) vaginal and 3 of 48 (6%) throat samples were positive. Both bovine and human beta haemolytic isolates were characterized biochemically and serologically. Pigment production was a characteristic of both human and bovine beta haemolytic isolates. The majority (88%) of human isolates fermented salicin and not lactose and most bovine isolates were either lactose positive/salicin positive (41%) or lactose positive/salicin negative (38%). Human and bovine isolates were 100% and 85% typable respectively. Serotype distribution was similar in the bovine and human populations with serotype la, lc and lll being most common in both. Fermentation of sugars showed major differences between bovine and human isolates but similarity in serotype distribution suggests some genetic relationship.

Pulsed field gel electrophoresis (PFGE) of the genomic DNA of penicillin resistant serotype 19B Streptococcus pneumoniae was carried out. Thirteen strains form the Nagasaki area and 12 strains from other areas in Japan were examined. Twenty-three strains were resistant to erythromycin, tetracycline and trimethoprim/sulfamethoxazole but susceptible to chloramphenicol. Eight strains were resistant to ceftriaxone. All strains were multiply resistant. Five strains isolated from Nagasaki were indistinguishable from each other by using restriction enzymes Apa I and Sma I. Two strains isolated from other areas were indistinguishable from the above five strains. We could classify 13 Nagasaki strains into 3 groups and the total of 25 Japanese strains into 6 groups. These results suggest that the increasing prevalence of multiply drug resistant S. pneumoniae serotyped 19B in Japan is not due to a single clone, but at least one clone has spread widely in Japan.

This study assessed accuracy of (a) recording Vibrio vulnificus infection on death certificates and (b) International Classification of Disease (ICD)-9 codes for V. vulnificus. Patients with microbiologically confirmed V. vulnificus infection were identified as part of co-ordinated surveillance in four USA Gulf Coast states between 1989 and 1993. Of 60 deaths, 51 death certificates were reviewed and V. vulnificus was recorded as the immediate cause of death on 11 (22%). There was no ICD-9 code for V. vulnificus infection, thus no patients had an ICD-9 code indicating V. vulnificus infection. Of 23 certificates where V. vulnificus was recorded on the death certificate, only 5 (22%) were coded for Gram-negative, septicaemia. This study highlights the importance of teaching physicians how to provide epidemiologically meaningful data on death certificates and the need for accurate ICD mortality codes.

The effectiveness of influenza vaccine in reducing hospital admissions for pneumonia, influenza, bronchitis, or emphysema was assessed by a case-control study of people aged 16 years and older who were admitted to 10 Leicestershire hospitals between 1 December 1989 and 31 January 1990. Hospital and general practitioners' records for 156 admissions (the cases) and 289 controls matched for age and sex were reviewed. Information was collected on demography, the usual place of residence (institutional or non-institutional), the existence of chronic illness, and vaccination during the 5 years before admission. The odds ratio for hospital admission among vaccinees was 0·67 (95% CI 0·39–1·12) giving an estimate of vaccine effectiveness in this setting of 33% (95% CI 0–61). However, multivariate logistic regression, adjusting for the effects of institutional care and chronic illness, revealed that influenza vaccination reduced hospital admissions by 63% (95% CI 17–84%). There was a strong trend towards improved vaccine effectiveness when used in institutional settings. Influenza vaccine is effective in reducing hospital admissions for influenza, pneumonia, bronchitis and emphysema, and effectiveness is comparable to that observed for influenza and pneumonia admissions in North America.

Variations in the sero-prevalence of antibody to brucella infection by cow, farm and area factors were investigated for three contrasting districts in Kenya: Samburu, an arid and pastoral area; Kiambu, a tropical highland area; and Kilifi, a typical tropical coastal area. Cattle were selected by a two-stage cluster sampling procedure and visited once between August 1991 and 1992.

Schall's algorithm, a statistical model suitable for multi-level analysis was used. Using this model, older age, free grazing and large herd size ([ges ] 31) were associated with higher seroprevalence. Also, significant farm-to-farm, area-to-area and district-to-district variations were estimated. The patterns of high risk districts and areas seen were consistent with known animal husbandry and movement risk factors, but the larger than expected farm-to-farm variation within high risk areas and districts could not be explained. Thus, a multi-level method provided additional information beyond conventional analyses of sero-prevalence data.

Rapid, non-culture, serogroup determination of meningococcal infection is important in contact management where vaccination may be possible. The impending availability of polysaccharide–protein conjugate vaccines for serogroup C disease requires maximal case ascertainment, with serogroup determination, at a time when the number of culture confirmed meningococcal infections is decreasing. A polymerase chain reaction assay (PCR), based on a restriction fragment length polymorphism (RFLP) in the meningococcal serogroup B and C sialyltransferase (siaD) gene, was developed to combine the non-culture diagnosis of meningococcal infection from CSF, whole blood and serum with serogroup (B and C) identification. The PCR assay was adapted to an ELISA format incorporating hybridization with serogroup-specific B and C oligonucleotide probes. Specificity for CSFs was 100% and sensitivities were respectively 81, 63 and 30% for CSFs, whole blood and sera. The serogroup-specific PCR ELISA is a significant addition to currently available tests for non-culture diagnosis of meningococcal infection and outbreak investigation.

To obtain insights into the pathogenic mechanisms involving Mycobacterium paratuberculosis in Crohn's disease (CD) we questioned if the strains of M. paratuberculosis isolated from CD are distinguishable from those involved in Johne's disease (JD), a chronic granulomatous enteritis in cattle. Accordingly we compared human and animal strains at the DNA level, both by the analysis of restriction fragment length polymorphism (RFLP) in and around the insertion sequence IS 900 and by the arbitrarily primed polymerase chain reaction (AP-PCR). Results are in favour of a common clonal origin for the 4 strains isolated from CD and for 8 of the 11 strains isolated from cattle and sheep JD.

A clinical trial was conducted in Argentina to determine the efficacy of clarithromycin plus lansoprazole for the treatment of Helicobacter pylori in duodenal ulcers and non-ulcer dyspepsia. PCR–RFLP was conducted on an 820-bp amplified product of the ureC gene of H. pylori to determine the genetic heterogeneity of 83 pretreatment and 21 post-treatment isolates. Twelve different restriction patterns were observed when digested with Sau 3A or Hha I, resulting in 40 different RFLP types. Comparison of isolates before treatment to after treatment showed that 20 of 20 patients had the same RFLP type. In addition, the presence of the cytotoxin-associated gene (cagA) and the vacuolating gene (vacA) were determined. All pretreatment isolates were positive for vacA whereas 75% of the pretreatment isolates were positive for cagA. The results of this study indicate that a high degree of heterogeneity exists among H. pylori and that infection is not limited to a small number of RFLP types.

A sentinel surveillance system for the control of sexually transmitted diseases (STD) among foreigners was developed in Italy in 1991. From January 1991 to June 1995, 4030 foreigners with a new STD episode were reported. More than one-third of them were North-Africans. The most frequent STDs were non-specific urethritis and genital warts among men, and non-specific vaginitis and latent syphilis among women. The overall HIV prevalence was 5%, with large differences in rates in people from different continents. Very high HIV-positivity rates were observed among homosexuals and homosexual IDUs from Central–South America, with 39·1% and 77·8% seropositive individuals respectively.

These data stress the need for increased knowledge of both the spread of and risk factors for STDs among immigrants. Particular attention should be paid to counselling procedures focused on the prevention of risk behaviours for acquiring STDs and HIV infection.

The prevalence of African horse sickness (AHS) serotypes in zebra foals from the Kruger National Park, South Africa was examined for possible associations between serotypes and to estimate the basic reproduction number, R0. The distributions of serotypes between zebra were not independent in the 6- and 7–8-month-old age classes (P < 0·005). This does not necessarily imply biological interactions between serotypes, as heterogeneity in host-vector transmission rates can generate non-independent distributions of serotypes. Both age and month of capture were significant factors in the number of serotypes infecting each zebra (P < 0·0001). Pairwise, positive associations between non-cross-reacting serotypes were found in the 7–8-month-old class only. For AHS overall, estimates of R0 ranged from 31–68. Assuming serotypes are transmitted independently, estimates of R0 for individual serotypes ranged from 10 for serotype 1 to 23 for serotype 6. The wide range of estimates emphasizes the need for a better understanding of serotype transmission and interactions in AHS.

Viruses from the recent epidemic of swine vesicular disease (SVD) in Europe have been isolated and characterized by antigenic and genetic methods to examine the likely epidemiological origins of the disease. Antigenic analysis was performed on 77 SVD viruses (SVDV) isolated in Europe between 1966 and 1994 using two panels of monoclonal antibodies (MAb) in a trapping ELISA. Genetic analysis of 33 of the SVD viruses by reverse transcription-polymerase chain-reaction (RT-PCR) amplification and nucleotide sequencing of the 1D (VP1) coding region was also performed. Comparison of the nucleotide sequences with each other and with three other previously published SVDV sequences revealed four distinct groups which correlated exactly with the results of the pattern of reactivity with MAbs. The first group consisted solely of the earliest SVD virus isolated (ITL/1/66) while the second group comprised viruses present in Europe and Japan between 1972 and 1981. The third group consisted of viruses isolated from outbreaks of SVD in Italy between December 1988 and June 1992. Viruses isolated between 1987 and 1994 from Romania, the Netherlands, Italy and Spain formed a fourth group. The genetic and antigenic similarity of the most recent virus isolates from Western Europe to a virus isolated in Romania 5 years previously suggests that the possible origin of the recent epidemic of swine vesicular disease in Western Europe was in Eastern Europe.

An Hasidic Jewish community has experienced recurrent hepatitis A outbreaks since 1980. To assess risk factors for illness during a 1985–6 outbreak, the authors reviewed case records and randomly selected 93 households for an interview and serologic survey. In the outbreak, 117 cases of hepatitis A were identified, with the highest attack rate (4·2%) among 3–5 year olds. Among the survey households, the presence of 3–5 year olds was the only risk factor that increased a household's risk of hepatitis A (indeterminant relative risk, P=0·02). Furthermore, case households from the outbreak were more likely to have 3–5 year olds than were control households from the survey (odds ratio=16·4, P<0·001). Children 3–5 years old were more likely to have hepatitis A and may have been the most frequent transmitters of hepatitis A in this community. Hepatitis A vaccination of 3–5 year olds can protect this age group and might prevent future outbreaks in this community.