The occurrence of extended-spectrum β-lactamase producing enterobacteria (ESBLE) has been prospectively surveyed in a neurosurgical intensive care unit (ICU). Of the 47 patients examined, 8 were identified as faecal carriers, and 2 of them developed a subsequent urinary tract infection. ESBLE were also detected in the immediate environment of five colonized and/or infected patients. All isolates were Klebsiella pneumoniae of a particular biotype which exhibited a similar antibiotype and produced an SHV-4 type β-lactamase. However, plasmid profiling and ribotyping revealed that strains isolated from seven patients of hall A were a single epidemic clone, whereas strains isolated from the eighth patient of hall B were different. Comparison between the characteristics of patients who carried an ESBLE during the surveillance period, and control patients who did not, showed that a recent surgery, and the length of ICU stay were significantly associated with the acquisition of ESBLE.

The aim of this study was to identify risk factors for acute diarrhoea (AD) during the summer in France. A matched case-control study was conducted at a national level among patients of 500 general practitioners (GPs). From July to September 1996, 468 case-control pairs were included. Cases were more likely than controls (i) to live away from their main residence (OR 3·0; 95% CI 1·6–5·7), (ii) to have returned from a country at high risk of AD (OR 4·6; CI 0·9–23·1), and (iii) to have been in contact with a case of AD (OR 2·0; CI 1·3–3·1). A significantly decreased risk of AD was found for consumption of well-cooked chicken (OR 0·5; CI 0·3–0·8) and raw or undercooked home-made egg-containing products (OR 0·6; CI 0·4–0·8). These findings suggest that travel to high-risk areas, or travel within France, and being in contact with a case of AD, are risk factors for the occurrence of AD in summer in France.

The purposes of this study were to determine whether microorganisms can be isolated from the membranes of stethoscopes used by clinicians and nurses, and to analyse whether or not the degree of bacterial colonization could be reduced with different cleaning methods. We designed a transversal before-after study in which 122 stethoscopes were examined. Coagulase negative staphylococci (which are also potentially pathogenic microorganisms) were isolated together with 13 other potentially pathogenic microorganisms, including S. aureus, Acinetobacter sp. and Enterobacter agglomerans. The most effective antiseptic was propyl alcohol. Analysis of the cleaning habits of the Emergency Department (ED) staff, showed that 45% cleaned the stethoscope annually or never. The isolation of potentially pathogenic microorganisms suggests that the stethoscope must be considered as a potential vector of infection not only in the ED but also in other hospital wards and out-patient clinics.

We previously reported an outbreak of vancomycin resistant enterococci (VRE) in a paediatric oncology unit in December 1995 which was associated with widespread environmental contamination of the unit with VRE. We undertook this study to evaluate the effectiveness of the infection control policy instituted subsequent to the outbreak and to investigate the underlying prevalence of VRE colonization in hospitalized, outpatient and community-based children. We sought to establish the molecular similarity of VRE isolates from the study. Stool specimens were obtained from outpatients at risk of VRE, hospital inpatients and from healthy community-based children. VRE colonization was eradicated from the inpatient unit within 11 months, but in outpatients, 16 months after the outbreak, 4 of 137 (2·9%) attending oncology outpatients, 5 of 65 (7·7%) with cystic fibrosis and 1 of 12 (8·3%) with liver disease were found to be colonized with VRE. The isolates were all Enterococcus faecium, Van A phenotype except one E. casseliflavus of the Van C phenotype. All were unique in SmaI DNA macrorestriction patterns with the exception of two isolates, which were similar to the original outbreak strain and three further isolates of a single strain but which differed from the outbreak strain. Of 315 hospital inpatients, 2·5% were colonized with VRE of the Van C resistance phenotype but VRE was not detected in 116 healthy, community-based children. We conclude that effective strategies can successfully control spread of VRE but despite a low prevalence of VRE colonization in hospital patients and in community-based children, outbreaks can occur when infection control practices are not optimal. Continued vigilance to detect VRE and limit spread within hospitals is therefore necessary.

Clostridium perfringens isolates are currently classified into one of five biotypes on the basis of the differential production of α-, β-, ε- and ι-toxins. Different biotypes are associated with different diseases of man and animals. In this study a multiple PCR assay was developed to detect the genes encoding these toxins. In addition, detection of the genes encoding the C. perfringens enterotoxin and β2-toxin allowed subtyping of the bacteria. C. perfringens isolates taken from a variety of animals, including foals, piglets or lambs, were genotyped using this assay. Most of the isolates were found to be genotype A and the gene encoding β-toxin was present in 50% of the isolates genotyped. A significant association between C. perfringens possessing the β2-toxin gene and diarrhoea in piglets was identified, suggesting that β2-toxin may play a key role in the pathogenesis of the disease.

Aboriginal Australians in northern Australia are subject to endemic infection with group A streptococci, with correspondingly high rates of acute rheumatic fever and rheumatic heart disease. For 12 communities with good ascertainment, the estimated lifetime cumulative incidence of acute rheumatic fever was approximately 5·7%, whereas over the whole population, with less adequate ascertainment, the cumulative incidence was only 2·7%. The corresponding prevalences of established rheumatic heart disease were substantially less than the cumulative incidences of acute rheumatic fever, at least in part because of poor ascertainment. The cumulative incidence of acute rheumatic fever estimates the proportion of susceptible individuals in endemically exposed populations. Our figures of 2·7–5·7% susceptible are consistent with others in the literature. Such comparisons suggest that the major part of the variation in rheumatic fever incidence between populations is due to differences in streptococcal exposure and treatment, rather than to any difference in (genetic) susceptibility.

Results from statutory testing of private water supplies in nine Public Health Laboratories in England were compiled, and the effects of supply class, source, treatment and location on water quality were examined. A total of 6551 samples from 2911 supplies was examined, over a 2-year period, of which 1342 (21%) samples, and 949 (33%) supplies on at least one occasion, failed current regulations for Escherichia coli. Total coliforms, including E. coli, were detected in 1751 (27%) samples from 1215 (42%) supplies. The percentage of samples positive for E. coli was highest in summer and autumn, and lowest in winter. Samples taken from larger supplies and from boreholes were less frequently contaminated than those from other sources. Chlorination, filtration or UV light treatment improved the bacteriological quality of supplies, but still resulted in a low level of compliance with the regulations. The public health implications of the study are discussed.

Incidence data by age of new episodes of influenza-like illness reported by sentinel general practice networks in England and Wales and in The Netherlands over a 10-year period were examined to provide estimates of the consulting population during influenza epidemic periods. Baseline levels of recording in each age group were calculated from weeks in which influenza viruses were not circulating and the excess over baseline calculated to provide the population estimates during influenza epidemics.

Influenza A/H3N2 epidemics were associated with higher population estimates for consultations than influenza B, especially in the age groups 0–4 and 65 years and over. In the intervening age groups, population estimates were more consistent regardless of the virus type. Both networks reported simultaneous peaking of incidence rates in all of the age groups. There were substantial increases in the number of persons reporting other respiratory illnesses during influenza epidemics.

Population estimates of the consulting population provide the only secure basis for which health services resource utilization during influenza epidemics can be estimated.

The induction of immunological memory to serogroup A and C polysaccharides in UK infants immunized with three doses of a meningococcal A/C oligosaccharide CRM197 conjugate vaccine was investigated. Forty UK infants vaccinated previously with three doses of a meningococcal A/C oligosaccharide-CRM197 conjugate vaccine at 2, 3 and 4 months of age, were revaccinated at a mean age of 145·6 weeks with either a 10 or 50 μg dose of licensed meningococcal A/C polysaccharide vaccine. Serogroup-specific antibody and serum bactericidal antibody (SBA) responses were measured by enzyme-linked immunosorbent assay and serum bactericidal assays, respectively. Following challenge, anti-serogroup A and C polysaccharide antibody levels rose from pre-booster geometric mean concentrations (GMC) of 3·1 and 2·1 μg/ml respectively to 19·6 and 21·0 μg/ml 1 month post-booster. Serum bactericidal antibody geometric mean titres (GMTs) for serogroups A and C increased 156- and 113-fold from 2·1 and 7·1 pre-booster respectively to 327·4 and 800·7 post-booster. A serogroup A control group of 45 children received a 10 μg dose of licensed meningococcal A/C polysaccharide vaccine (with no prior history of serogroup A vaccination) had serogroup A SBA GMTs of 2·3 pre-vaccination rising to 8 post-vaccination with corresponding GMCs of 0·8 and 10·8 μg/ml. These rises in SBA following serogroup A/C conjugate vaccination are indicative of immunological priming.

In the week following a carnival during 19–24 February 1998, an outbreak of meningococcal disease occurred in a rural German county. The available isolates belonged to phenotype C[ratio ]2a[ratio ]P1.2,5 and were clonally related by pulsed-field gel electrophoresis. A case-control study was done to identify risk factors for the outbreak and to define possible vaccination target groups. Five persons aged 13–16 years who fell ill during 24–27 February were included in the study. Four of 5 cases and 10 of 32 controls visited local discotheques (OR = 8·8; P = 0·06). Cases also visited discotheques more frequently than controls (χ2 for trend, P = 0·0002).Multiple discotheques during the carnival may have been predominant locations of transmission in this outbreak. Because this risk factor was limited in time, a mass community vaccination campaign was not initiated.

Close contacts of cases of meningococcal disease are at increased risk of disease themselves. We identified household-like contacts of index cases, to investigate whether relevant target groups are informed, receive and follow recommended chemoprophylaxis and vaccination, and to ascertain the time delay for implementation of these measures. A telephone interview of 172 households of index cases and a questionnaire survey among 634 parents of contacts of cases in institutions were carried out. Results were compared with reports from Medical Officers of Health. In 21% of the cases, Medical Officers reported fewer household-like contacts than were identified in this study. Written information was effective. However, 59% of households, and 36% of parents of contacts in institutions felt a lack of information about how the disease is acquired, the risk and signs of illness. For household-like contacts the coverage rate for chemoprophylaxis with an appropriate drug was 90% and for vaccination 59%. No secondary cases occurred among those treated with chemoprophylaxis, but among those not treated, there were two secondary cases. The study design provided a useful audit methodology to evaluate the completeness of implementation and the success of prophylactic measures for meningococcal disease.

To estimate the immunity of the Dutch population against vaccine-preventable diseases, a population-based serum bank was established. Since a multi-tiered approach to enrol eligible individuals was used, both the overall non-response selection and the effect, on this selection, of including additional participants and of excluding a subgroup of non-participants (i.e. those without questionnaire data) could be studied. For some characteristics associated with non-participation, an association with seroprevalence of vaccine-preventable diseases is likely (e.g. age, gender). For other characteristics (e.g. marital status, receipt of reminder, degree of urbanization) the association with immune status is unclear but probably small. If the distribution in the population, or information on all participants and non-participants, of the characteristic is available, then the effect on the seroprevalence can be estimated. However, investigators have to be aware that studying only a subgroup of non-participants might lead to a biased insight into non-participation selection. Furthermore, merely including additional participants might not always reduce this bias.

We describe an outbreak of meningitis at a Sudanese refugee camp in Northern Uganda that lasted over a year from February 1994. Some 291 cases occurred in a refugee population of 96860 (averaged over the year), an attack rate of 0·30%. The case fatality rate was 13·3%. From a small number of samples taken for culture N. meningitidis serogroup A, serotype 21[ratio ]P1·9, clone III-1 was identified as the causative organism. The outbreak started in the camp's reception centre which had the highest attack rate. Spread from the reception centre was rapid and the epidemic reached its peak within 3 weeks. All of the cases amongst residents of the reception centre reported having had meningococcal vaccine before arriving at the camp and so were not immunized on arrival as would normally have been the case. Some 37547 doses of meningococcal vaccine were used in a mass immunization campaign in February and March 1994. Following this the outbreak was declared over in August 1994 when no cases were registered for 2 consecutive weeks. However, following a massive and sudden influx of refugees a new epidemic peak occurred during February 1995. Many of these new refugees were also not immunized on arrival due to pressures of numbers. A follow-up immunization campaign then brought an end to the outbreak. Our experience confirms the effectiveness of timely and high-coverage immunization campaigns in controlling group A meningitis outbreaks amongst refugees in Africa.

Failure to seroconvert (primary vaccine failure) is believed to be the principal reason (approx. > 95%) why some vaccinees remain susceptible to measles and is often attributed to the persistence of maternal antibodies in children vaccinated at a young age. Avidity testing is able to separate primary from secondary vaccine failures (waning and/or incomplete immunity), but has not been utilized in measles epidemiology. Low-avidity (LA) and high-avidity (HA) virus-specific IgG antibodies indicate primary and secondary failure, respectively. Measles vaccine failures (n = 142; mean age 10·1 years, range 2–22 years) from an outbreak in 1988–9 in Finland were tested for measles–virus IgG avidity using a protein denaturating EIA. Severity of measles was recorded in 89 failures and 169 non-vaccinees (mean age 16·2 years, range 2–22 years). The patients with HA antibodies (n = 28) tended to have clinically mild measles and rapid IgG response. Among failures vaccinated at < 12, 12–15 and > 15 months of age with single doses of Schwarz-strain vaccine in the 1970s, 50 (95% CI 1–99), 36 (CI 16–56) and 25% (CI 8–42) had HA antibodies, respectively. When a single measles, mumps and rubella (MMR) vaccine had been given after 1982 at 15 months of age, only 7% (CI 0–14) showed HA antibodies. Omitting re-vaccinees and those vaccinated at < 15 months, Schwarz-strain recipients had 3·6 (CI 1·1–11·5) higher occurrence of HA responses compared to MMR recipients. Apart from one municipality, where even re-vaccinees had high risk of primary infection, 89% (CI 69 to ∼ 100) of the infected re-vaccinees had an HA response. Secondary measles-vaccine failures are more common than was more previously thought, particularly among individuals vaccinated in early life, long ago, and among re-vaccinees. Waning immunity – even among individuals vaccinated after 15 months of age, without the boosting effect of natural infections should be considered a relevant possibility in future planning of vaccination against measles.

Fifty-seven bacterial isolates previously identified as Bordetella avium or B. hinzii were characterized by restriction enzyme analysis (REA) and/or ribotyping. Twenty restriction endonucleases were evaluated for REA. Digestion of chromosomal DNA from the 42 B. avium and 15 B. hinzii isolates with Hinf I produced 8 and 7 distinct fingerprint profiles, respectively. Digestion with DdeI further discriminated these Bordetella species and produced 12 fingerprint profiles for B. avium and 4 profiles of B. hinzii. In addition, B. avium isolates were clearly distinguishable from B. hinzii isolates by ribotyping with the restriction endonuclease PvuII. The ribotype patterns of these two species of Bordetella were unique when compared to previously reported ribotype patterns for B. bronchiseptica isolates. Since it was possible to discern differences among isolates within each Bordetella species by REA analysis, we suggest that REA could be used in developing a typing system based on the fingerprint profiles generated.

We reviewed retrospectively all invasive Haemophilus influenzae (Hi) infections in adults ascertained from reference laboratory records and notifications from five NHS regions over the 5 years from 1 October 1990, a period encompassing the introduction of routine Hib childhood immunization (October 1992). A total of 446 cases were identified, a rate of 0·73 infections per 105 adults per annum. Though numbers of Hib infections in adults fell after the introduction of Hib vaccines for children (P = 0·035), and there was no increase in infections caused by other capsulated Hi serotypes, total numbers of invasive Hi infections increased due to a large rise in infections caused by non-capsulated Hi (ncHi) strains (P = 0·0067). There was an unexpectedly low rate of infections in those aged 75 years or more (P < 0·0001). The commonest clinical presentations were pneumonia with bacteraemia (227/350, 65%) and bacteraemia alone (62/350, 18%) and the highest rates of disease were in the 65–74 years age group (P < 0·0001). Clinical presentation was not influenced by the capsulation status of the invading Hi strain. 103/350 cases (29%) died within 1 month, and 207/350 (59%) within 6 months of their Hi infection. Case fatality rates were high in all age groups. Pre-existing diseases were noted in 220/350 cases and were associated with a higher case fatality rate (82% vs. 21%, P < 0·0001). After the introduction of Hib immunization in children, invasive Hib infections in unimmunized adults also declined, but the overall rate of invasive Hi disease in adults increased, with most infections now caused by non-capsulated strains. Physicians and microbiologists should be aware of the changing epidemiology, the high associated mortality and high risk of underlying disease. Invasive haemophilus infections in adults should be investigated and treated aggressively.

From March to July 1996 a measles outbreak occurred in northern Luxembourg with 110 reported cases centered around two primary schools (85 cases) and the surrounding community (25 cases). Eighty four suspected cases were confirmed serologically. Vaccine coverage was estimated from questionnaire-based surveys at the two primary schools to be 70 and 76%, respectively. Vaccine efficacy during the outbreak was estimated to be 94.6% [95% confidence interval (CI) 90·4–97·0]. Using the information from the school surveys, we obtained estimates of the basic reproduction number of measles of 7·7 (95% CI 4·4–11·0) and 6·2 (95% CI 3·5–8·9), respectively. Assuming a 95% vaccine efficacy, these estimates correspond to minimal vaccine coverages of 91·6% (95% CI 81·4–95·7) and 88·3% (95% CI 75·5–93·4) which would have been necessary to minimize the chances of a major outbreak occurring. We can confirm that major outbreaks in similar school settings can only be prevented if vaccination coverage exceeds 90%.

The age-specific immunity to human parvovirus infection was estimated in Victoria, Australia using prospectively collected samples from the Royal Children's Hospital, the Royal Women's Hospital and the Australian Red Cross Blood Service and from sera stored at the Victorian Infectious Diseases Reference Laboratory (VIDRL). All testing was performed at VIDRL using a commercial enzyme-linked immunosorbent assay (Biotrin). Of the 824 sera tested, 28% of those drawn from people aged 0–9 years contained protective antibodies to human parvovirus. This rose to 51% in the next decade of life. There was then a slow rise to about 78% immunity over 50 years of age. An analysis of all requests for parvovirus serology at VIDRL from 1992 to 1998 suggested that parvovirus tended to occur in 4-year cycles, with 2 epidemic years followed by 2 endemic years. A review of published reports of parvovirus immunity suggested that parvovirus infection may be more common, with a correspondingly higher proportion of the community immune, in temperate as opposed to tropical countries.

The predominant H. pylori strain circulating among geographic locations differs with regard to the genomic structure. This study determined whether structural subtypes of the cagA 3′ repeat region could be used to identify the population of origin of H. pylori isolates. We examined 600 cagA-positive H. pylori (Colombia, 100; USA, 100; France, 100; Canada, 20; Italy, 20; Korea, 100; Japan, 100; Hong Kong, 20; Taiwan, 20; Vietnam, 20). The cagA 3′ region was amplified by PCR using primers specific to Japanese and Western 3′ cagA gene sequences. PCR using Japanese cagA primers resulted in PCR products in 99·6% of strains from East Asia but no non-Asian strains. Conversely, PCR using Western cagA primers resulted in amplicons in 100% of non-Asian strains, and only one from East Asia. cagA genotyping is useful for molecular epidemiological studies as strains can be completely separated by differences in the cagA 3′ region.

Reports have suggested that isoniazid treatment may be associated with poor concentration and subtle reduction in memory. This study examines attentional function and processing speed in a group of 25 adolescents who received isoniazid prophylaxis for at least 6 months. As adolescents often face major educational assessment milestones, such cognitive side effects may have important implications. Participants were assessed before treatment, 1 month into treatment and at least 1 week after treatment cessation. Measures included the Paced Auditory Serial Addition Test and subtests of the appropriate Wechsler scale sensitive to attention and speed of information processing. Isoniazid does not appear to cause significant adverse effects on attentional function in adolescents.