Obaghe Edeghere

Large outbreak of verocytotoxin-producing Escherichia coli O157 infection in visitors to a petting farm in South East England, 2009

SUMMARY In the summer of 2009, an outbreak of verocytotoxigenic Escherichia coli O157 (VTEC O157) was identified in visitors to a large petting farm in South East England. The peak attack rate was 6/1000 visitors, and highest in those aged <2 years (16/1000). We conducted a case-control study with associated microbiological investigations, on human, animal and environmental samples. We identified 93 cases; 65 primary, 13 secondary and 15 asymptomatic. Cases were more likely to have visited a specific barn, stayed for prolonged periods and be infrequent farm visitors. The causative organism was identified as VTEC O157 PT21/28 with the same VNTR profile as that isolated in faecal specimens from farm animals and the physical environment, mostly in the same barn. Contact with farm livestock, especially ruminants, should be urgently reviewed at the earliest suspicion of a farm-related VTEC O157 outbreak and appropriate risk management procedures implemented without delay.

Surveillance of antibiotic susceptibility of urinary tract pathogens for a population of 5.6 million over 4 years

OBJECTIVES To retrospectively analyse routine susceptibility testing data to describe antimicrobial non-susceptibility trends in isolates of Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa from urine samples in a population of 5.6 million people over a 4 year period. METHODS De-duplicated laboratory data submitted to the AmSurv surveillance system from the West Midlands region of England and results of submissions to the Antimicrobial Resistance and Healthcare Associated Infections Reference Unit were extracted for the period 2010-13. Descriptive analysis of the non-susceptibility of selected Gram-negative organisms to key antibiotics, as recommended for monitoring in the UK Five Year Antimicrobial Resistance Strategy, was undertaken. RESULTS During the study period, there were 431 461 reports for E. coli, 23 786 for K. pneumoniae and 6985 for P. aeruginosa from urine specimens. These represented 61%, 3% and 1%, respectively, of all organisms isolated from urine specimens. There was a linear increase in non-susceptibility to third-generation cephalosporins for E. coli and K. pneumoniae, and to ciprofloxacin for E. coli, in specimens from both hospital and community settings (P < 0.001). The proportions of E. coli and K. pneumoniae reported non-susceptible to meropenem and/or imipenem remained low during the study period, with no evidence of linear trend (P ≥ 0.05). CONCLUSIONS Automated antimicrobial resistance surveillance enabled, for the first time in England, the systematic monitoring of resistance in bacteria responsible for urinary tract infections in a defined population, and thereby provided a representative indication of the burden of resistance in Gram-negative bacteria in hospital and community settings.

AmWeb: a novel interactive web tool for antimicrobial resistance surveillance, applicable to both community and hospital patients

BACKGROUND Antimicrobial resistance (AMR) is recognized as one of the most significant threats to human health. Local and regional AMR surveillance enables the monitoring of temporal changes in susceptibility to antibiotics and can provide prescribing guidance to healthcare providers to improve patient management and help slow the spread of antibiotic resistance in the community. There is currently a paucity of routine community-level AMR surveillance information. METHODS The HPA in England sponsored the development of an AMR surveillance system (AmSurv) to collate local laboratory reports. In the West Midlands region of England, routine reporting of AMR data has been established via the AmSurv system from all diagnostic microbiology laboratories. The HPA Regional Epidemiology Unit developed a web-enabled database application (AmWeb) to provide microbiologists, pharmacists and other stakeholders with timely access to AMR data using user-configurable reporting tools. RESULTS AmWeb was launched in the West Midlands in January 2012 and is used by microbiologists and pharmacists to monitor resistance profiles, perform local benchmarking and compile data for infection control reports. AmWeb is now being rolled out to all English regions. CONCLUSIONS It is expected that AmWeb will become a valuable tool for monitoring the threat from newly emerging or currently circulating resistant organisms and helping antibiotic prescribers to select the best treatment options for their patients.

Evaluation of the National Notifiable Diseases Surveillance System for Dengue Fever in Taiwan, 2010–2012

Background In Taiwan, around 1,500 cases of dengue fever are reported annually and incidence has been increasing over time. A national web-based Notifiable Diseases Surveillance System (NDSS) has been in operation since 1997 to monitor incidence and trends and support case and outbreak management. We present the findings of an evaluation of the NDSS to ascertain the extent to which dengue fever surveillance objectives are being achieved. Methodology We extracted the NDSS data on all laboratory-confirmed dengue fever cases reported during 1 January 2010 to 31 December 2012 to assess and describe key system attributes based on the Centers for Disease Control and Prevention surveillance evaluation guidelines. The system’s structure and processes were delineated and operational staff interviewed using a semi-structured questionnaire. Crude and age-adjusted incidence rates were calculated and key demographic variables were summarised to describe reporting activity. Data completeness and validity were described across several variables. Principal Findings Of 5,072 laboratory-confirmed dengue fever cases reported during 2010–2012, 4,740 (93%) were reported during July to December. The system was judged to be simple due to its minimal reporting steps. Data collected on key variables were correctly formatted and usable in > 90% of cases, demonstrating good data completeness and validity. The information collected was considered relevant by users with high acceptability. Adherence to guidelines for 24-hour reporting was 99%. Of 720 cases (14%) recorded as travel-related, 111 (15%) had an onset >14 days after return, highlighting the potential for misclassification. Information on hospitalization was missing for 22% of cases. The calculated PVP was 43%. Conclusions/Significance The NDSS for dengue fever surveillance is a robust, well maintained and acceptable system that supports the collection of complete and valid data needed to achieve the surveillance objectives. The simplicity of the system engenders compliance leading to timely and accurate reporting. Completeness of hospitalization information could be further improved to allow assessment of severity of illness. To minimize misclassification, an algorithm to accurately classify travel cases should be established.

Estimating the positive predictive value of opportunistic population testing for gonorrhoea as part of the English Chlamydia Screening Programme

Advances in technology have raised the possibility of including gonorrhoea testing as part of chlamydia screening. In England this is recommended only where the positive predictive value (PPV) of the test is >90%. This study assessed the PPV for gonorrhoea testing using routine testing data. Routine data (including gonorrhoea testing) from the Greater Manchester Chlamydia Screening Programme (GMCSP) in 2009/2010, were used to estimate the PPV for gonorrhoea testing. Of those screened, 0.3% (59/18044) of men and 0.4% (174/41873) of women tested positive for gonorrhoea. The PPV was 82.3% in women and 73.6% in men, in those who also tested positive for chlamydia. For women and men testing negative for chlamydia the PPV for a positive gonorrhoea test was incalculable. The low PPV observed in most groups suggests that where population testing for gonorrhoea occurs there is a need for further confirmatory testing of positive results before treatment decisions are made. Clinicians should be aware of screening test result limitations in this context.

Novel public health risk assessment process developed to support syndromic surveillance for the 2012 Olympic and Paralympic Games

Background Syndromic surveillance aims to provide early warning and real time estimates of the extent of incidents; and reassurance about lack of impact of mass gatherings. We describe a novel public health risk assessment process to ensure those leading the response to the 2012 Olympic Games were alerted to unusual activity that was of potential public health importance, and not inundated with multiple statistical ‘alarms’. Methods Statistical alarms were assessed to identify those which needed to result in ‘alerts’ as reliably as possible. There was no previously developed method for this. We identified factors that increased our concern about an alarm suggesting that an ‘alert’ should be made. Results Between 2 July and 12 September 2012, 350 674 signals were analysed resulting in 4118 statistical alarms. Using the risk assessment process, 122 ‘alerts’ were communicated to Olympic incident directors. Conclusions Use of a novel risk assessment process enabled the interpretation of large number of statistical alarms in a manageable way for the period of a sustained mass gathering. This risk assessment process guided the prioritization and could be readily adapted to other surveillance systems. The process, which is novel to our knowledge, continues as a legacy of the Games.

Limiting worker exposure to highly pathogenic avian influenza a (H5N1): a repeat survey at a rendering plant processing infected poultry carcasses in the UK

BackgroundCurrent occupational and public health guidance does not distinguish between rendering plant workers and cullers/poultry workers in terms of infection risk in their respective roles during highly pathogenic avian influenza poultry outbreaks. We describe an operational approach to human health risk assessment decision making at a large rendering plant processing poultry carcasses stemming from two separate highly pathogenic avian influenza A (H5N1) outbreaks in England during 2007.MethodsDuring the first incident a uniform approach assigned equal exposure risk to all rendering workers in or near the production line. A task based exposure assessment approach was adopted during the second incident based on a hierarchy of occupational activities and potential for infection exposure. Workers assessed as being at risk of infection were offered personal protective equipment; pre-exposure antiviral prophylaxis; seasonal influenza immunisation; hygiene advice; and health monitoring. A repeat survey design was employed to compare the two risk assessment approaches, with allocation of antiviral prophylaxis as the main outcome variable.ResultsTask based exposure assessment during the second incident reduced the number of workers assessed at risk of infection from 72 to 55 (24% reduction) when compared to the first incident. No cases of influenza like illness were reported in workers during both incidents.ConclusionsTask based exposure assessment informs a proportionate public health response in rendering plant workers during highly pathogenic avian influenza H5N1 outbreaks, and reduces reliance on extensive antiviral prophylaxis.

Effect of general practice characteristics and antibiotic prescribing on Escherichia coli antibiotic non-susceptibility in the West Midlands region of England: a 4 year ecological study

Objectives To assess the effect of general practice characteristics and antibiotic prescribing on the number of non-susceptible Escherichia coli isolated from urine specimens submitted from community settings, we undertook an ecological study of the general practice population in the West Midlands. Methods Descriptive analysis and multilevel modelling of temporal trends in antibiotic prescribing and non-susceptibility of E. coli urine isolates to a range of antibiotics prescribed in the community over a 4 year period. Results Nine of the 16 antibiotic prescribing/non-susceptibility combinations demonstrated a significant statistical linear correlation with non-susceptibility either for prescribing in a quarter or for prescribing within the previous 12 months. The magnitude of the effect varied, from a 0.3% increase in the odds of non-susceptibility to ampicillin/amoxicillin (when prescribing ampicillin/amoxicillin) to a 6.3% increase in the odds of non-susceptibility to nitrofurantoin (when prescribing nitrofurantoin) for an increase of 50 DDDs per 1000 practice population within a quarter (equivalent to ∼10 courses of antibiotics). In all 16 models, single-handed general practices were shown to have a significant association with increased numbers of non-susceptible E. coli urine isolates (adjusted ORs 1.083-1.657). Increased prescribing of ampicillin/amoxicillin in winter periods was associated with increased non-susceptibility of E. coli isolated from urine specimens. Conclusions Small increases in antibiotic prescribing in individual general practices reduce the number of susceptible bacteria in the practice population. To maintain the effectiveness of available treatment, antibiotic stewardship should be encouraged and supported within each practice.

What is the utility of using syndromic surveillance systems during large subnational infectious gastrointestinal disease outbreaks? An observational study using case studies from the past 5 years in England.

Syndromic surveillance systems in England have demonstrated utility in the early identification of seasonal gastrointestinal illness (GI) tracking its spatio-temporal distribution and enabling early public health action. There would be additional public health utility if syndromic surveillance systems could detect or track subnational infectious disease outbreaks. To investigate using syndromic surveillance for this purpose we retrospectively identified eight large GI outbreaks between 2009 and 2014 (four randomly and four purposively sampled). We then examined syndromic surveillance information prospectively collected by the Real-time Syndromic Surveillance team within Public Health England for evidence of possible outbreak-related changes. None of the outbreaks were identified contemporaneously and no alerts were made to relevant public health teams. Retrospectively, two of the outbreaks - which happened at similar times and in proximal geographical locations - demonstrated changes in the local trends of relevant syndromic indicators and exhibited a clustering of statistical alarms, but did not warrant alerting local health protection teams. Our suite of syndromic surveillance systems may be more suited to their original purposes than as means of detecting or monitoring localized, subnational GI outbreaks. This should, however, be considered in the context of this studys limitations; further prospective work is needed to fully explore the use of syndromic surveillance for this purpose. Provided geographical coverage is sufficient, syndromic surveillance systems could be able to provide reassurance of no or minor excess healthcare systems usage during localized GI incidents.

Developing a Multidisciplinary Syndromic Surveillance Academic Research Program in the United Kingdom: Benefits for Public Health Surveillance:

Syndromic surveillance is growing in stature internationally as a recognised and innovative approach to public health surveillance. Syndromic surveillance research uses data captured by syndromic surveillance systems to investigate specific hypotheses or questions. However, this research is often undertaken either within established public health organisations or the academic setting, but often not together. Public health organisations can provide access to health-related data and expertise in infectious and non-infectious disease epidemiology and clinical interpretation of data. Academic institutions can optimise methodological rigour, intellectual clarity and establish routes for applying to external research funding bodies to attract money to fund projects. Together, these competencies can complement each other to enhance the public health benefits of syndromic surveillance research. This paper describes the development of a multidisciplinary syndromic surveillance academic research programme in England, United Kingdom, its aims, goals and benefits to public health.