Impact of infection control interventions on rates of Staphylococcus aureus bacteraemia in National Health Service acute hospitals, East Midlands, UK, using interrupted time-series analysis.

BACKGROUND: Reducing healthcare-associated infection (HCAI) is a UK national priority. Multiple national and regional interventions aimed at reduction have been implemented in National Health Service acute hospitals, but assessment of their effectiveness is methodologically challenging. AIM: To assess the effectiveness of national and regional interventions undertaken between 2004 and 2008 on rates of meticillin-resistant Staphylococcus aureus (MRSA) and meticillin-sensitive Staphylococcus aureus (MSSA) bacteraemia within acute hospitals in the East Midlands, using interrupted time-series analysis. METHODS: We used segmented regression to compare rates of MRSA and MSSA bacteraemia in the pre-intervention, implementation, and post-intervention phases for combined intervention packages in eight acute hospitals. FINDINGS: Most of the change in MSSA and MRSA rates occurred during the implementation phase. During this phase, there were significant downward trends in MRSA rates for seven of eight acute hospital groups; in four, this was a steeper quarter-on-quarter decline compared with the pre-intervention phase, and, in one, an upward trend in the pre-intervention phase was reversed. Regarding MSSA, there was a significant positive effect in four hospital groups: one upward trend during the pre-intervention phase was reversed, two upward trends plateaued, and in one hospital group an indeterminate trend decreased significantly. However, there were significant increasing trends in quarterly MSSA rates in four hospital groups during the implementation or post-intervention periods. CONCLUSION: The impact of interventions varied by hospital group but the overall results suggest that national and regional campaigns had a beneficial impact on MRSA and MSSA bacteraemia within the East Midlands.

Twenty year surveillance of invasive pneumococcal disease in Nottingham: serogroups responsible and implications for immunisation.

AIMS: To evaluate the incidence, spectrum of clinical manifestations, and outcome of invasive pneumococcal disease (IPD) in children. To determine the major serogroups of Streptococcus pneumoniae responsible for invasive disease and the potential coverage by the new pneumococcal conjugate vaccines. METHODS: Analysis of prospectively recorded information of all children admitted to two teaching hospitals in Nottingham with IPD between January 1980 and December 1999. RESULTS: A total of 266 episodes of IPD in children were identified; 103 (39%) were aged <1 year and 160 (60%) <2 years. Major clinical presentations were meningitis in 86 (32%), pneumonia in 82 (31%), and bacteraemia without an obvious focus in 80 (30%). The age specific mean annual incidence rates of IPD overall among children aged <1, <2, and <5 years were 47.1, 37.8, and 20 per 100 000 population, respectively. Mortality rates for children with meningitis and non-meningitic infection were 20% and 7%, respectively. Neurological sequelae following meningitis were documented in 16 (26%) of the 61 survivors assessed. The potential coverage rates in children between the ages of 6 months and 5 years are 84% by the 7-valent, 91% by the 9-valent, and 95% by the 11-valent conjugate vaccines. CONCLUSION: This study indicates that inclusion of a pneumococcal conjugate vaccine in the primary immunisation programme in the UK would have a considerable effect on the mortality and morbidity associated with IPD.

Factors influencing hepatitis B vaccine uptake in injecting drug users.

BACKGROUND: Hepatitis B infection in injecting drug users is an important public health problem. Active immunization against hepatitis B is immunogenic and safe, but uptake rates in targeted vaccination programmes are low. This study was undertaken to identify factors associated with the uptake of hepatitis B vaccination in injecting drug users attending a needle exchange service. METHODS: A retrospective cross-sectional survey of case-note data of injecting drug users who had no markers of hepatitis B infection or immunity was undertaken within a drop-in needle exchange service for injecting drug users in a large urban area in England. A qualitative study using semi-structured interviews with needle exchange staff was also conducted. RESULTS: Of 207 injecting drug users, 180 (87 per cent) had been offered vaccine, 123 (59 per cent) accepted at least one dose and 55 (27 per cent) received three or more doses. Vaccine was less likely to be offered to those sharing injecting equipment or known to have hepatitis C. Needle sharing was also associated with failure to accept vaccine, as was increasing age and the length of contact with the service. CONCLUSIONS: Those who are most at risk are least likely to be offered vaccine and accept it. This calls into doubt the effectiveness of hepatitis B vaccination strategies targeted at high-risk groups and adds weight to arguments for universal vaccination.

Enteric fever and other extraintestinal salmonellosis in University Hospital, Nottingham, UK, between 1980 and 1997.

The clinical spectrum of extraintestinal salmonellosis comprises enteric fever (typhoid and paratyphoid) and invasive infections due to nontyphoidal salmonellae. This study describes the clinical spectrum, management and outcome of all confirmed cases of extraintestinal salmonellosis in patients admitted to University Hospital, Nottingham, UK, between 1980 and 1997. There were 142 cases (children, 42; adults, 100) of extraintestinal salmonellosis, of which 38 (children, 20; adults, 18) were enteric fever, consisting of 21 cases of typhoid, 12 of paratyphoid A and five of paratyphoid B. All patients with typhoid and paratyphoid A fever were from Indian or Pakistani families and, except for two adults, all were considered to be previously fit. The outcome in patients with enteric fever was excellent, and there were no complications. Of the 104 patients (children, 22; adults, 82) with nontyphoidal salmonellosis, 69 were bacteraemic secondary to gastroenteritis, 10 were bacteraemic without an obvious focus of infection and 25 had focal infections. The three major sites of focal infections were meningitis in five infants, osteomyelitis in two children and three adults, and arterial infections in ten adults. The three most frequently isolated organisms were Salmonella enteritidis (40%), Salmonella typhimurium (25%) and Salmonella virchow (14%). Sixty-seven percent of these patients had underlying disease(s)/risk factors. In contrast to the outcome of enteric fever, there were 19 deaths (children, 2; adults, 17) in patients with nontyphoidal salmonellosis. Sixteen of the 17 adults who died were over the age of 60 years. Eight (25%) of 32 males over the age of 60 years with nontyphoidal Salmonella bacteraemia had arterial infections. In some patients, the diagnosis of Salmonella arterial infection is likely to be delayed or missed altogether if blood cultures are not obtained. Mortality in patients over the age of 60 years with nontyphoidal Salmonella infections was 28%.

Dynamics of meningococcal long-term carriage among university students and their implications for mass vaccination.

In the 1997-98 academic year, we conducted a longitudinal study of meningococcal carriage and acquisition among first-year students at Nottingham University, Nottingham, United Kingdom. We examined the dynamics of long-term meningococcal carriage with detailed characterization of the isolates. Pharyngeal swabs were obtained from 2,453 first-year students at the start of the academic year (October), later on during the autumn term, and again in March. Swabs were immediately cultured on selective media, and meningococci were identified and serologically characterized. Nongroupable strains were genetically grouped using a PCR-based assay. Pulsed-field gel electrophoresis was used to determine the link between sequential isolates. Of the carriers initially identified in October, 44.1% (98 of 222) were still positive later on in the autumn (November or December); 57.1% of these remained persistent carriers at 6 months. Of the index carriers who lost carriage during the autumn, 16% were recolonized at 6 months. Of 344 index noncarriers followed up, 22.1% acquired carriage during the autumn term and another 13.7% acquired carriage by March. Overall, 43.9% (397 of 904) of the isolates were noncapsulated (serologically nongroupable); by PCR-based genogrouping, a quarter of these belonged to the capsular groups B and C. The ratio of capsulated to noncapsulated forms for group B and C strains was 2.9 and 0.95, respectively. Sequential isolates of persistent carriers revealed that individuals may carry the same or entirely different organisms at different times. We identified three strains that clearly switched their capsular expression on and off at different times in vivo. One student developed invasive meningococcal disease after carrying the same organism for over 7 weeks. The study revealed a high rate of turnover of meningococcal carriage among students. Noncapsulated organisms are capable of switching their capsular expression on and off (both ways) in the nasopharynx, and group C strains are more likely to be noncapsulated than group B strains. Carriage of a particular meningococcal strain does not necessarily protect against colonization or invasion by a homologous or heterologous strain.

Changing carriage rate of Neisseria meningitidis among university students during the first week of term: cross sectional study.

OBJECTIVE: To determine the rates of, and risk factors for, meningococcal carriage and acquisition among university students. DESIGN: Repeated cross sectional study. PARTICIPANTS: 2,507 students in their first year at university. MAIN OUTCOME MEASURES: Prevalence of carriage of meningococci and risk factors for carriage and acquisition of meningococci. RESULTS: Carriage rates for meningoccoci increased rapidly in the first week of term from 6.9% on day 1, to 11.2% on day 2, to 19.0% on day 3, and to 23.1% on day 4. The average carriage rate during the first week of term in October among students living in catered halls was 13.9%. By November this had risen to 31.0% and in December it had reached 34. 2%. Independent associations for acquisition of meningococci in the autumn term were frequency of visits to a hall bar (5-7 visits: odds ratio 2.7, 95% confidence interval 1.5 to 4.8), active smoking (1.6, 1.0 to 2.6), being male (1.6, 1.2 to 2.2), visits to night clubs (1. 3, 1.0 to 1.6), and intimate kissing (1.4, 1.0 to 1.8). Lower rates of acquisition were found in female only halls (0.5, 0.3 to 0.9). The most commonly acquired meningococcal strain was C2a P1.5 (P1.2), which has been implicated in clusters of invasive meningococcal disease at other UK universities. CONCLUSIONS: Carriage rates of meningococci among university students increase rapidly in the first week of term, with further increases during the term. The rapid rate of acquisition may explain the increased risk of invasive meningococcal disease and the timing of cases and outbreaks in university students.

A collaborative approach to management of chlamydial infection among teenagers seeking contraceptive care in a community setting.

OBJECTIVES: To develop and assess a coordinated model of care for effective management of genital chlamydial infection in young women, identified through a selective screening programme in a community based teenage health clinic. METHODS: Selective screening for genital Chlamydia trachomatis was undertaken among young women aged 13-19 years who were having a routine cervical smear test, being referred for termination of pregnancy, or who reported behavioural risk factors, for, and/or symptoms of, genital infection. Collaboration among family planning, genitourinary medicine (GUM), and public health staff was used to enhance management of infected individuals, with particular focus on partner notification. RESULTS: 94 young women had confirmed genital chlamydial infection, representing 11% of those tested. All index patients received appropriate antibiotic therapy and follow up; 93 (99%) of these were counselled by a health adviser, of whom 62 (66%) were able to provide sufficient details for partner notification, resulting in treatment of male partners associated with 51 (82%) of these young women. Younger age (< or = 16 years) was significantly associated with delay in attending for treatment. CONCLUSIONS: Effective management of genital chlamydial infection is achievable in settings outside GUM clinics using a collaborative approach which incorporates cross referencing between community based services and GUM clinics.

Seven-week interval between acquisition of a meningococcus and the onset of invasive disease. A case report.

Invasive meningococcal disease (IMD) is thought to occur within a few days of pharyngeal acquisition of Neisseria meningitidis. During a longitudinal study of carriage and acquisition among 2453 first-year undergraduates we identified a male student from whom N. lactamica was isolated in October 1997 followed by N. meningitidis in December 1997. In mid-January 1998 this student suffered a mild episode of IMD (meningitis) during which N. meningitidis was isolated from his CSF. The meningococcus carried in December 1997 was phenotypically and genotypically indistinguishable from the invading organism, suggesting the possibility that the organism may have been carried for 7 weeks prior to the onset of invasive disease. Further studies are needed to assess more accurately the range of asymptomatic carriage prior to disease onset.

Diabetes mellitus, anti-secretory drugs and other risk factors for campylobacter gastro-enteritis in adults: a case-control study.

The epidemiology of notified cases of campylobacter gastroenteritis in adults in Nottingham Health District was investigated using a case-control study with a postal questionnaire to ascertain data on risk factors. Over a 14-month period 531 cases (a 73% response rate of all laboratory confirmed cases) and 512 controls replied. Conditional logistic regression analysis was used to determine independent associations with infection. These included foreign travel (odds ratio (OR) 3.4; 95% confidence intervals (CI) 2.0-5.7), diabetes mellitus (OR 4.1, CI 1.1-17), medication with omeprazole (OR 3.5, CI 1.1-12) and H2 and H2 antagonists (OR 3.7, CI 1.3-15), contact with puppies (OR 11.3, CI 1.2-105), eating chicken (OR 1.4, CI 1.1-1.8) and drinking milk from bottles with tops damaged by a bird (OR 3.3, CI 1.0-11). Preparing main meals (OR 0.9, CI 0.8-1.0) and drinking delivered milk (OR 0.6, CI 0.4-0.9) were associated with a reduced risk of campylobacter infection. Foreign travel was reported in 25% of cases and another 15% had significant associations with other risk factors. The majority of cases, 60%, remained unexplained, indicating the need for further evolution of sporadic cases.