Infections In England Research Articles

PMD59 Assessment of Administrative Data for Evaluating the Shifting Acquisition of Clostridium Difficile Infection in England

PMD59 Assessment of Administrative Data for Evaluating the Shifting Acquisition of Clostridium Difficile Infection in England

Assessment of administrative data for evaluating the shifting acquisition of Clostridium difficile infection in England

Little is known about the acquisition of Clostridium difficile infection (CDI) and whether it represents hospital- or community-acquired infection. To test the feasibility and value of using national hospital admissions data from Hospital Episode Statistics to examine trends in CDI in England. Hospital Episode Statistics from the period 1997/98 to 2009/10 were used. Time trends were analysed using two different denominators of hospital activity: total admissions and total bed-days. We explored the impact of sociodemographic factors, comorbidity and healthcare pathways on the risk of CDI. CDI rates per admission and per bed-days increased from 1997/98 to 2006/07, then decreased significantly by >50% from 2008/9 and 2009/10. This pattern was similar for patients regardless of probable source of infection but the proportion of probable community-acquired CDI cases rose steadily from 7% in 1997/98 to 13% in 2009/10. CDI rates were higher among older patients (odds ratio: >65 years, 10.9), those with more comorbid conditions (odds ratio for Charlson index: >5, 5.6), and among patients admitted as an emergency compared with elective admissions, but no relationship was found with deprivation score. Our findings support not only the falling trend in CDI found in the national mandatory surveillance scheme from the Health Protection Agency, but a growing proportion of CDI presenting on admission with no evidence of prior hospital exposure in the previous 90 days. We suggest that these may be community-acquired CDI cases.

The epidemiology of invasive non-type b encapsulated Haemophilus influenzae disease in England & Wales in the era of routine Hib immunisation

Following the introduction of the routine 12 month Hib booster in the national childhood immunisation programme in September 2006, other encapsulated H. influenzae infections are now more common than Hib. The Health Protection Agency routinely follow-up all cases of invasive H. influenzae infections in England and Wales. The objective of ths study was to describe the epidemiology, clinical presentation and outcome of invasive non-type b encapsulated H. influenzae between January 2009 and March 2010.

Travel‐AssociatedSalmonellaandCampylobacterGastroenteritis in England: Estimation of Under‐Ascertainment Through National Laboratory Surveillance

Increased international travel raises the importance of accurate surveillance of travel-associated gastroenteric pathogens to improve treatment and the investigation of cross-border outbreaks. This study found that 45% of Salmonella and 17% of Campylobacter infections in England were travel-associated, but only 29 and 3% of travel histories were accurately identified by national laboratory surveillance. More structured data collection forms and staff training may be needed to address this.

Increased incidence of Mycoplasma pneumoniae infection in England and Wales in 2010: multiocus variable number tandem repeat analysis typing and macrolide susceptibility

An epidemic of Mycoplasma pneumoniae infection began in Denmark in late 2010. A similar increase in M. pneumoniae infections was noted in England and Wales in the same period, with a decline in early 2011. Multiocus variable number tandem repeat analysis typing and analysis of macrolide resistance markers indicate that at least nine known and two novel strain types were circulating in England and Wales during October 2010 to January 2011. There was no evidence of macrolide resistance.

Reflections on Screening Blood Donors for the Presence of Virus Infections in England

Reflections on Screening Blood Donors for the Presence of Virus Infections in England

Hepatitis B and residual risk of infection in English and Welsh blood donors, 1996 through 2008

Globally, of all infections that donations are tested for, hepatitis B has the highest residual risk of transfusion transmission, despite donor selection criteria and advances in testing. Every blood donation in England and Wales is tested for hepatitis B surface antigen. Knowledge of infections being detected can inform donor selection and testing strategies. Data on donation testing and infections detected are collated by the NHS Blood and Transplant and Health Protection Agency Epidemiology Unit. Infected donors are classified as having acute or chronic hepatitis B virus (HBV) by a clinician; their demographic characteristics were described. The prevalence (by acute or chronic HBV status, ethnicity, and geography) and incidence of infection were calculated between 1996 and 2008. The residual risk was calculated for four periods using a modification of the incidence and window period model; the effects of modifying variables were investigated. Most infections (1047/1155) detected were chronic and seen in new donors. People with acute infections were more likely to be white and/or born in Western Europe. Prevalence was highest in donors from minority ethnic communities and in London. Incidence in repeat donors has halved in recent years. The estimated frequency of an infectious donation being missed was 1.37 per million donations (2006-2008), the lowest since surveillance began or three per year. Many HBV infections in England and Wales were detected among new donors, who had chronic infection and were born overseas. The residual risk of infection declined over the 13 study years, but is still higher for HBV than other viral infections for which testing is undertaken.

Age-specific incidence of A/H1N1 2009 influenza infection in England from sequential antibody prevalence data using likelihood-based estimation.

Estimating the age-specific incidence of an emerging pathogen is essential for understanding its severity and transmission dynamics. This paper describes a statistical method that uses likelihoods to estimate incidence from sequential serological data. The method requires information on seroconversion intervals and allows integration of information on the temporal distribution of cases from clinical surveillance. Among a family of candidate incidences, a likelihood function is derived by reconstructing the change in seroprevalence from seroconversion following infection and comparing it with the observed sequence of positivity among the samples. This method is applied to derive the cumulative and weekly incidence of A/H1N1 pandemic influenza in England during the second wave using sera taken between September 2009 and February 2010 in four age groups (1–4, 5–14, 15–24, 25–44 years). The highest cumulative incidence was in 5–14 year olds (59%, 95% credible interval (CI): 52%, 68%) followed by 1–4 year olds (49%, 95% CI: 38%, 61%), rates 20 and 40 times higher respectively than estimated from clinical surveillance. The method provides a more accurate and continuous measure of incidence than achieved by comparing prevalence in samples grouped by time period.

Increase in invasive Streptococcus pyogenes and Streptococcus pneumoniae infections in England, December 2010 to January 2011

Increases in invasive Streptococcus pyogenes and S. pneumoniae above the seasonally expected levels are currently being seen in England. Preliminary analyses suggest that the high level of influenza activity seen this winter may be contributing to an increased risk of concurrent invasive bacterial and influenza infections in children and young adults.

No effect of 2008/09 seasonal influenza vaccination on the risk of pandemic H1N1 2009 influenza infection in England

This study reports effectiveness of trivalent influenza vaccine (TIV) against confirmed pandemic influenza infection in England using a retrospective test-negative case–control study. Cases and controls were frequency matched by age, swabbing-week and region. On univariable and multivariable analysis adjusted for underlying clinical risk factors, cases were no more or less likely than controls to be vaccinated with 2008–09 or 2007–08 season TIV. Adjusted vaccine effectiveness for the former was −6% (−43% to 22%). Vaccine effectiveness did not differ significantly by age-group or hospitalisation status. There was no evidence prior vaccination with TIV significantly altered subsequent risk of pandemic influenza H1N1 2009 infection.

Central line change in potential catheter-related bloodstream infection: target for intervention to reduce harm

Central venous catheterization is routine in critical care, but a potential source of harm. Forty-two per cent of bloodstream infections in England are central-line related [1], at a substantial cost to the health service. Early catheter removal is vital for source control where catheter-related bloodstream infection (CRBSI) is suspected. Furthermore, a model encompassing daily review and removal of unnecessary catheters has been shown to reduce the risk [2]. We studied the time from decision to removal of existing central venous catheters (CVCs), and evaluated potential reasons for delay.

Effectiveness of pandemic and seasonal influenza vaccine in preventing pandemic influenza A(H1N1)2009 infection in England and Scotland 2009-2010

Following the global spread of pandemic influenza A(H1N1)2009, several pandemic vaccines have been rapidly developed. The United Kingdom and many other countries in the northern hemisphere implemented seasonal and pandemic influenza vaccine programmes in October 2009. We present the results of a case–control study to estimate effectiveness of such vaccines in preventing confirmed pandemic influenza infection. Some 5,982 individuals with influenza-like illness seen in general practices between November 2009 and January 2010 were enrolled. Those testing positive on PCR for pandemic influenza were assigned as cases and those testing negative as controls. Vaccine effectiveness was estimated as the relative reduction in odds of confirmed infection between vaccinated and unvaccinated individuals. Fourteen or more days after immunisation with the pandemic vaccine, adjusted vaccine effectiveness (VE) was 72% (95% confidence interval (CI): 21% to 90%). If protection was assumed to start after seven or more days, the adjusted VE was 71% (95% CI: 37% to 87%). Pandemic influenza vaccine was highly effective in preventing confirmed infection with pandemic influenza A(H1N1)2009 from one week after vaccination. No evidence of effectiveness against pandemic influenza A(H1N1)2009 was found for the 2009/10 trivalent seasonal influenza vaccine (adjusted VE of -30% (95% CI: -89% to 11%)).

Hepatitis C infection among recent initiates to injecting in England 2000–2008: Is a national hepatitis C action plan making a difference?

Around 80% of hepatitis C virus (HCV) infections in England are among injecting drug users (IDUs). The HCV Action Plan launched in 2004 includes targets to reduce HCV prevalence in recent initiates (those starting injecting in the preceding 3 years), and to increase HCV voluntary confidential testing (VCT). The Action Plan's impact is examined using surveillance data from recent initiates participating in an annual survey of IDUs in contact with specialist services across England, 2000-2008. Participants provided an oral fluid sample (tested for anti-HCV) and completed a short questionnaire (including HCV VCT and result of last test). Overall, anti-HCV prevalence among the recent initiates was 18% (619/3463); in 2004, it was 20% (59/291), other than being lower in 2000 [11%, 73/672, adjusted odds ratio (AOR) = 0.63 95%CI 0.42-0.93] there was no change over time. Prevalence increased with age; was higher among those ever imprisoned, using a needle exchange, and having a HCV VCT; and varied by region. Overall, 42% (1460) had ever had a HCV VCT; in 2004 uptake was 45% (130/291) having increased from 26% (175/672, AOR = 0.57 95%CI 0.42-0.77) in 2000, and it rose to 62% (197/320, AOR = 2.12 95%CI 1.50-2.99) in 2008. The proportion of anti-HCV-positive IDUs aware of their infection was higher in 2006-2008 than in earlier years. The HCV Action Plan has probably helped increase recent initiates' uptake of HCV VCT and the proportion of those diagnosed with HCV infection. However, its impact on HCV transmission is unclear. There is a need to reinvigorate, and improve coverage of, interventions to prevent HCV transmission.

A conceptual model of interventions to increase diagnosis of acute HIV infection and reduce forward transmission.

Approximately 56,000 individuals in the US acquire HIV annually [1, 2]. Newly-infected persons are highly infectious during the first 2–4 months following HIV acquisition—a period known as acute HIV infection (AHI)—and consequently contribute disproportionately to HIV transmissions. In this paper, we discuss a conceptual model that incorporates interventions specifically targeting AHI that have the potential to greatly decrease new HIV infections. Two important properties distinguish acute HIV infection from the later, chronic stage of HIV infection. First, AHI is characterized by exceptionally high levels of virus circulating in the blood and in the genital tract [3–9]. Plasma and genital tract viral load levels are positively correlated with the risk of sexual transmission [4, 5, 10]. The high-level viremia observed during acute infection results in greatly increased risks of HIV transmission during sexual or syringe-sharing activities. The risk of transmission during acute HIV infection is approximately 8–22 times greater, on a per-act basis, than it is during the subsequent period of chronic infection [5, 11]. Consequently, and despite the relatively brief period during which persons are acutely-infected, the acute period of infection plays a disproportionate role in fueling nascent epidemics and sustaining more mature epidemics [12–16]. Simulation and mathematical models of the mature epidemics in the UK and US suggest that between 10 and 20% of sexually-transmitted infections can be attributed to acute-phase transmission [12, 17]. Moreover, phylogenetic analyses of persons with recent infection in England and Quebec suggest that 25–50% of recently-acquired infections are due to transmission during the early or acute-phase of HIV infection [13, 16]. The second distinguishing characteristic of AHI is that antibodies against HIV are not detectable during much of the acute period of infection. Formation of HIV antibodies usually occurs 2–4 weeks after HIV is acquired [7, 18]. Antibody levels detectable by standard enzyme-linked immunoassay (EIA, ELISA) screening tests are not reliably present until 4–8 weeks after infection. As a consequence, acutely-infected individuals usually have negative or indeterminate antibody test results [3, 18]. Current HIV screening strategies mainly rely on HIV antibody tests. Unfortunately, even the most aggressive antibody-based testing strategy will fail to identify HIV-infected individuals during AHI, when the risk of onward transmission is greatest. The annual incidence of new HIV infections in the US has remained relatively constant for more than a decade [1]. To reduce HIV incidence below the current plateau, innovative HIV prevention strategies are needed, including interventions to increase AHI diagnoses and prevent transmission of the virus during AHI. Currently, accurate diagnosis of AHI requires the use of HIV nucleic acid amplification tests that detect the presence of HIV RNA, rather than antibodies against the virus. We have developed a conceptual model of potential targets of AHI-specific interventions to increase AHI diagnoses and to reduce HIV transmission through a combination of increased RNA testing in both public health and clinical settings; education of at-risk individuals, health care providers, and HIV counselors; and implementation of timely and efficient partner notification programs.

The continuing crisis in antibiotic resistance

The emergence of antibiotic resistance in bacterial pathogens is an inevitable consequence of antibiotic use. Despite repeated warnings, negligent antibiotic use and poor infection-control practice have led to the continuing development of extensive resistance problems worldwide. Multidrug-resistant pathogens are now characterized by their heterogeneity, increasing virulence, resistance even to reserve agents and spread within and between hospitals and the community. Examples are glycopeptide-resistant meticillin-resistant Staphylococcus aureus (MRSA) and enterococci, extended-spectrum β-lactamase- and carbapenemase-producing coliforms, and toxin-hyperproducing Clostridium difficile. Effective national and international programmes of control to combat these problems are urgently needed. The potential for success of such coordinated efforts has been demonstrated by the recent dramatic reductions in MRSA and C. difficile infections in England.

Paediatric mortality related to pandemic influenza A H1N1 infection in England: an observational population-based study

Young people (aged 0-18 years) have been disproportionately affected by pandemic influenza A H1N1 infection. We aimed to analyse paediatric mortality to inform clinical and public health policies for future influenza seasons and pandemics. All paediatric deaths related to pandemic influenza A H1N1 infection from June 26, 2009, to March 22, 2010 in England were identified through daily reporting systems and cross-checking of records and were validated by confirmation of influenza infection by laboratory results or death certificates. Clinicians responsible for each individual child provided detailed information about past medical history, presentation, and clinical course of the acute illness. Case estimates of influenza A H1N1 were obtained from the Health Protection Agency. The primary outcome measures were population mortality rates and case-fatality rates. 70 paediatric deaths related to pandemic influenza A H1N1 were reported. Childhood mortality rate was 6 per million population. The rate was highest for children aged less than 1 year. Mortality rates were higher for Bangladeshi children (47 deaths per million population [95% CI 17-103]) and Pakistani children (36 deaths per million population [18-64]) than for white British children (4 deaths per million [3-6]). 15 (21%) children who died were previously healthy; 45 (64%) had severe pre-existing disorders. The highest age-standardised mortality rate for a pre-existing disorder was for chronic neurological disease (1536 per million population). 19 (27%) deaths occurred before inpatient admission. Children in this subgroup were significantly more likely to have been healthy or had only mild pre-existing disorders than those who died after admission (p=0·0109). Overall, 45 (64%) children had received oseltamivir: seven within 48 h of symptom onset. Vaccination priority should be for children at increased risk of severe illness or death from influenza. This group might include those with specified pre-existing disorders and those in some ethnic minority groups. Early pre-hospital supportive and therapeutic care is also important. Department of Health, UK.

Paediatric mortality related to H1N1 infection in England

Paediatric mortality related to H1N1 infection in England

Increasing reports of non-tuberculous mycobacteria in England, Wales and Northern Ireland, 1995-2006

BackgroundNon-tuberculous mycobacteria have long been identified as capable of causing human disease and the number at risk, due to immune-suppression, is rising. Several reports have suggested incidence to be increasing, yet routine surveillance-based evidence is lacking. We investigated recent trends in, and the epidemiology of, non-tuberculous mycobacterial infections in England, Wales and Northern Ireland, 1995-2006.MethodsHospital laboratories voluntarily report non-tuberculous mycobacterial infections to the Health Protection Agency Centre for Infections. Details reported include age and sex of the patient, species, specimen type and source laboratory. All reports were analysed.ResultsThe rate of non-tuberculous mycobacteria reports rose from 0.9 per 100,000 population in 1995 to 2.9 per 100,000 in 2006 (1608 reports). Increases were mainly in pulmonary specimens and people aged 60+ years. The most commonly reported species was Mycobacterium avium-intracellulare (43%); M. malmoense and M. kansasii were also commonly reported. M. gordonae showed the biggest increase over the study period rising from one report in 1995 to 153 in 2006. Clinical information was rarely reported.ConclusionsThe number and rate of reports increased considerably between 1995 and 2006, primarily in older age groups and pulmonary specimens. Increases in some species are likely to be artefacts but real changes in more pathogenic species, some of which will require clinical care, should not be excluded. Enhanced surveillance is needed to understand the true epidemiology of these infections and their impact on human health.

Attribution of Human Listeria monocytogenes Infections in England and Wales to Ready-to-Eat Food Sources Placed on the Market: Adaptation of the Hald Salmonella Source Attribution Model

Human listeriosis is a rare but serious foodborne disease, with high morbidity and mortality in vulnerable populations (e.g., pregnant women, the elderly, and the immunocompromised). The disease is predominantly caused by the consumption of contaminated ready-to-eat foods. Since 2001, an increase in the number of listeriosis cases has been observed in several European Union countries, including England and Wales, predominantly in the over-60s population. The cause of this selective increased incidence is unknown. The Hald Salmonella Bayesian source attribution model was adapted to determine the potential of this approach to quantify the contribution of different food sources to the burden of human listeriosis in England and Wales from 2004 to 2007. The most important food sources for the overall population were multicomponent foods (sandwiches and prepacked mixed salad vegetables) (23.1%), finfish (16.8%), and beef (15.3%). Attribution of major sources of infection was similar for the elderly population (>or=60 years old, multicomponent foods [22.0%], finfish [14.7%], and beef [13.6%]). For pregnancy-associated cases, beef (12.3%), milk and milk products (11.8%), and finfish (11.2%) were more important sources of infection. The adapted model also showed that the serotype 4b was associated with relatively more human infections than that of other serotypes; further, the subtype 4b amplified fragment-length polymorphism V was associated with more pregnancy-associated cases than other subtypes of 4b. This approach of quantifying the contribution of various food sources to human listeriosis provides a useful tool in food safety risk analysis, and underlines the need for further emphasis to be given to the reduction of Listeria monocytogenes in high-risk foods, such as multicomponent foods, which are consumed without any further treatment. The need for targeted dietary advice for the elderly population is also highlighted.

Invasive group A streptococcal infection

Invasive group A streptococcus (iGAS) is the most common cause of monomicrobial necrotising fasciitis. Necrotising infections of the extremities may present directly to orthopaedic surgeons or by reference from another admitting specialty. Recent epidemiological data from the Health Protection Agency suggest an increasing incidence of iGAS infection in England. Almost 40% of those affected had no predisposing illnesses or risk factors, and the proportion of children presenting with infections has risen. These observations have prompted the Chief Medical Officer for the Central Alerting System in England to write to general practitioners and hospitals, highlighting the need for clinical vigilance, early diagnosis and rapid initiation of treatment in suspected cases. The purpose of this annotation is to summarise the recent epidemiological trends, describe the presenting features and outline the current investigations and treatment of this rare but life-threatening condition.