Vakavien Streptococcus pyogenes -tautien epidemiologia Euroopassa

Diseases caused by the Lancefield group A streptococcus, Streptococcus pyogenes, are amongst the most challenging to clinicians and public health specialists alike. Although severe infections caused by S. pyogenes are relatively uncommon, affecting around 3 per 100,000 of the population per annum in developed countries, the case fatality is high relative to many other infections. Despite a long scientific tradition of studying their occurrence and characteristics, many aspects of their epidemiology remain poorly understood, and potential control measures undefined. Epidemiological studies can play an important role in identifying host, pathogen and environmental factors associated with risk of disease, manifestation of particular syndromes or poor survival. This can be of value in targeting prevention activities, as well directing further basic research, potentially paving the way for the identification of novel therapeutic targets. The formation of a European network, Strep-EURO, provided an opportunity to explore epidemiological patterns across Europe. Funded by the Fifth Framework Programme of the European Commission s Directorate-General for Research (QLK2.CT.2002.01398), the Strep-EURO network was launched in September 2002. Twelve participants across eleven countries took part, led by the University of Lund in Sweden. Cases were defined as patients with S. pyogenes isolated from a normally sterile site, or non-sterile site in combination with clinical signs of streptococcal toxic shock syndrome (STSS). All participating countries undertook prospective enhanced surveillance between 1st January 2003 and 31st December 2004 to identify cases diagnosed during this period. A standardised surveillance dataset was defined, comprising demographic, clinical and risk factor information collected through a questionnaire. Isolates were collected by the national reference laboratories and characterised according to their M protein using conventional serological and emm gene typing. Descriptive statistics and multivariable analyses were undertaken to compare characteristics of cases between countries and identify factors associated with increased risk of death or development of STSS. Crude and age-adjusted rates of infection were calculated for each country where a catchment population could be defined. The project succeeded in establishing the first European surveillance network for severe S. pyogenes infections, with 5522 cases identified over the two years. Analysis of data gathered in the eleven countries yielded important new information on the epidemiology of severe S. pyogenes infections in Europe during the 2000s. Comprehensive epidemiological data on these infections were obtained for the first time from France, Greece and Romania. Incidence estimates identified a general north-south gradient, from high to low. Remarkably similar age-standardised rates were observed among the three Nordic participants, between 2.2 and 2.3 per 100,000 population. Rates in the UK were higher still, 2.9/100,000, elevated by an upsurge in drug injectors. Rates from these northern countries were reasonably close to those observed in the USA and Australia during this period. In contrast, rates of reports in the more central and southern countries (Czech Republic, Romania, Cyprus and Italy) were substantially lower, 0.3 to 1.5 per 100,000 population, a likely reflection of poorer uptake of microbiological diagnostic methods within these countries. Analysis of project data brought some new insights into risk factors for severe S. pyogenes infection, especially the importance of injecting drug users in the UK, with infections in this group fundamentally reshaping the epidemiology of these infections during this period. Several novel findings arose through this work, including the high degree of congruence in seasonal patterns between countries and the seasonal changes in case fatality rates. Elderly patients, those with compromised immune systems, those who developed STSS and those infected with an emm/M78, emm/M5, emm/M3 or emm/M1 were found to be most likely to die as a result of their infection, whereas those diagnosed with cellulitis, septic arthritis, puerperal sepsis or with non-focal infection were associated with low risk of death, as were infections occurring during October. Analysis of augmented data from the UK found use of NSAIDs to be significantly associated with development of STSS, adding further fuel to the debate surrounding the role of NSAIDs in the development of severe disease. As a largely community-acquired infection, occurring sporadically and diffusely throughout the population, opportunities for control of severe infections caused by S. pyogenes remain limited, primarily involving contact chemoprophylaxis where clusters arise. Analysis of UK Strep-EURO data were used to quantify the risk to household contacts of cases, forming the basis of national guidance on the management of infection. Vaccines currently under development could offer a more effective control programme in future. Surveillance of invasive infections caused by S. pyogenes is of considerable public health importance as a means of identifying long and short-term trends in incidence, allowing the need for, or impact of, public health measures to be evaluated. As a dynamic pathogen co-existing among a dynamic population, new opportunities for exploitation of its human host are likely to arise periodically, and as such continued monitoring remains essential.Lancefield-ryhmän A streptokokin eli Streptococcus pyogenes-bakteerin aiheuttamat taudit ovat erittäin haasteellisia kliinikoille sekä kansanterveyden asiantuntijoille. Vaikka S. pyogenesin aiheuttamia vakavia infektioita esiintyy kehittyneissä maissa väestöpohjaisesti vain kolmella 100 000:sta vuosittain, on tapauskuolleisuus suuri verrattuna moniin muihin infektiotauteihin. Siitä huolimatta, että näiden infektioiden ominaisuuksia ja esiintymistä koskevalla tutkimuksella on pitkät perinteet, on niiden epidemiologia vielä useilta osin huonosti tunnettua ja mahdolliset torjuntakeinot määrittelemättä. Epidemiologisilla tutkimuksilla voi olla merkittävä rooli tautiriskiin, tiettyihin oireisiin tai huonoon selviytymiseen liittyvien isäntään, taudinaiheuttajaan ja ympäristötekijöihin liittyvien tekijöiden tunnistamisessa. Tämä voi osoittautua hyödylliseksi ehkäisytoimenpiteitä ja jatkotutkimuksia suunnitellessa, sekä toimia uraauurtavasti uusien hoidon kohteiden tunnistamisessa. Eurooppalaisen Strep-EURO- verkoston perustaminen mahdollisti epidemiologisten tekijöiden tutkimuksen ympäri Eurooppaa. Euroopan komission tutkimusdirektoraatin (QLK2.CT.2002.01398) viidennen puiteohjelman rahoittama Strep-EURO -verkosto perustettiin syyskuussa 2002. Hankkeeseen osallistui kaksitoista osanottajaa yhdestätoista maasta ruotsalaisen Lundin yliopiston johdolla. Tapauksiksi määriteltiin potilaat, joilta oli viljelty S. pyogenes joko normaalisti steriilistä tai epästeriilistä kohteesta yhdistettynä toksisen shokin taudinkuvaan (STSS). Prospektiivisen tehoseurantatutkimuksen avulla etsittiin kaikista osallistujamaista 1. tammikuuta 2003 ja 31. joulukuuta 2004 välisenä aikana diagnostisoituja potilastapauksia. Luotiin standardisoidu seurantatietokanta, joka sisälsi kyselylomakkeen avulla kerättyjä demografisia, kliinisiä ja riskitekijätietoja. Kansalliset asiantuntijalaboratoriot keräsivät bakteerilöydökset, ja tutkivat niiden M proteiineja perinteistä serologista ja emm -geenityypitystä hyödyntämällä. Deskriktiivinen tilasto- ja monimuuttuja-analyysi suoritettiin eri maiden välillä tautitapauksiin liittyvien ominaisuuksien sekä suurentuneeseen kuolemanriskiin tai STSS:n kehittymiseen liittyvien riskitekijöiden tunnistamiseksi. Infektioiden esiintymisluvut laskettiin sekä suoraan että ikäryhmiin mukautettuna kullekin maalle, jonka kohdeväestö oli määriteltävissä. Tunnistamalla 5522 tapausta kahden vuoden aikana, hanke onnistui luomaan ensimmäisen eurooppalaisen vakavien S. pyogenes infektioiden seurantaverkoston. Yhdessätoista maasta kerättyä materiaalia analysoimalla saatiin uutta, tärkeää tietoa vakavien S.pyogenes infektioiden epidemiologiasta Euroopassa 2000-luvulla. Kattavaa epidemiologista tietoa näistä infektioista oli saatavilla ensimmäistä kertaa Ranskasta, Kreikasta ja Romaniasta. Tapausten esiintymistiheys viittasi korkeasta alhaiseen kulkevaan pohjois-etelä gradienttiin. Kolmen pohjoismaalaisen osallistujan välillä oli nähtävissä huomattavan yhdenmukaiset ikävakioidut arvot, noin 2,2 -2,3 tapausta 100 000 asukasta kohti. Ruiskuhuumeita käyttävien äkillisesti nousseesta lukumäärästä johtuen olivat kyseiset luvut Iso-Britaniassa vielä korkeampia, noin 2,9/100 000. Näistä Pohjois-Euroopan maista saadut luvut vastasivat suunnilleen USA:sta ja Australiasta samalla aikavälillä saatuja arvoja. Euroopan keski- ja eteläosan maissa (Tsekin tasavalta, Romania, Kypros ja Italia) havaittiin sen sijaan huomattavasti vähemmän tapauksia ja kyseiset luvut vaihtelivat 0,3:n ja 1,5:n tapauksen välillä 100 000 asukasta kohti. Tämän voidaan mitä todennäköisimmin katsoa heijastuvan mikrobiologisten diagnostisten menetelmien vähemmästä käytöstä kyseisissä maissa. Projektitulosten analysointi toi joitakin uusia näkökulmia vakavien S. pyogenes tautien riskitekijöistä. Etenkin Iso-Britanniassa ruiskuhuumeiden käyttö ja näiden potilaiden infektiot muokkasivat merkittävästi tautiepidemiologiaa tänä ajanjaksona. Tutkimus tuotti paljon uusia tuloksia, kuten vuodenaikavaihtelun samankaltaisuuden kaikissa maissa, ja vuodenajan vaikutuksen tapauskuolleisuuteen. Iäkkäät ja puolustusrajoitteiset potilaat sekä henkilöt, joille oli kehittynyt STSS tai joilla oli emm/M78, emm/M5, emm/M3 tai emm/M1 tauti, kuolivat todennäköisimmin infektion seurauksena, kun taas selluliittia, septistä artriittia, puerperaalista sepsistä tai yleisinfektiota (ei elinfokusta) sairastavien potilaiden keskuudessa kuolemanriski oli alhainen. Kuolleisuus oli alhaisempaa myös, jos infektio esiintyi lokakuussa. Iso-Britannian laajennetun tietokeräysmateriaalin analyysissa NSAID lääkkeiden käyttö assosioitui tilastollisesti merkitsevästi STSS:n kehittymiseen. Tämä löydös saattaa osaltaan kiihdyttää keskustelua, jota käydään NSAID lääkkeiden roolista vakavan taudin kehittymiseen. Koska vakavat S.pyogenes infektiot ovat pitkälti avohoitoperäisiä, ja ajallisesti ja maantieteellisesti harvakseltaan esiintyviä tauteja, ovat torjuntakeinot vähäiset. Ne rajoittuvat lähinnä lähikontaktien lääkeprofylaksiaan, jos todetaan tautirypäitä. Iso-Britannian Strep-EURO tuloksia käytettiin arvioimaan samassa taloudessa asuvien henkilöiden tautiriskiä; tämä loi pohjaa kansallisen hoito-ohjeen luonnille. Kehitteillä olevat rokotteet voisivat tulevaisuudessa tarjota tehokkaamman torjuntaohjelman. Vakavien S. pyogenes infektioiden seuranta on kansanterveydellisesti tärkeää nimenomaan pitkän ja lyhyen ajanjakson esiintyvyydessä tapahtuvien muutosten tunnistamiseksi, sekä kansanterveydellisten toimenpiteiden tarpeen ja vaikutusten arvioimiseksi. S. pyogenes, joka on muuntautumiskykyinen taudinaiheuttaja, osaa väestössä ja isännässä tapahtuvien muutosten myötä etsiä aika ajoin uusia taudinaiheuttamismuotoja. Tämän takia jatkuva seuranta on tärkeää

Impact of national policies on the microbial aetiology of surgical site infections in acute NHS hospitals in England: analysis of trends between 2000 and 2013 using multi-centre prospective cohort data

Our study aimed to evaluate changes in the epidemiology of pathogens causing surgical site infections (SSIs) in England between 2000 and 2013 in the context of intensified national interventions to reduce healthcare-associated infections introduced since 2006. National prospective surveillance data on target surgical procedures were used for this study. Data on causative organism were available for 72% of inpatient-detected SSIs meeting the standard case definitions for superficial, deep and organ-space infections (9767/13 531) which were analysed for trends. A multivariable logistic linear mixed model with hospital random effects was fitted to evaluate trends by pathogen. Staphylococcus aureus was the predominant cause of SSI between 2000 (41%) and 2009 (24%), decreasing from 2006 onwards reaching 16% in 2013. Data for 2005–2013 showed that the odds of SSI caused by S. aureus decreased significantly by 14% per year [adjusted odds ratio (aOR) 0·86, 95% confidence interval (CI) 0·83–0·89] driven by significant decreases in methicillin-resistant S. aureus (MRSA) (aOR 0·71, 95% CI 0·68–0·75). However a small significant increase in methicillin-sensitive S. aureus was identified (aOR 1·06, 95% CI 1·02–1·10). Enterobacteriaceae were stable during 2000–2007 (12% of cases overall), increasing from 2008 (18%) onwards, being present in 25% of cases in 2013; the model supported these increasing trends during 2007–2013 (aOR 1·12, 95% CI 1·07–1·18). The decreasing trends in S. aureus SSIs from 2006 and the increases in Enterobacteriaceae SSIs from 2008 may be related to intensified national efforts targeted at reducing MRSA bacteraemia combined with changes in antibiotic use aimed at controlling C. difficile infections

Effect of Returning University Students on COVID-19 Infections in England, 2020

Each September in England, ≈1 million students relocate to study at universities. To determine COVID-19 cases and outbreaks among university students after their return to university during the COVID pandemic in September 2020, we identified students with COVID-19 (student case-patients) by reviewing contact tracing records identifying attendance at university and residence in student accommodations identified by matching case-patients’ residential addresses with national property databases. We determined COVID-19 rates in towns/cities with and without a university campus. We identified 53,430 student case-patients during September 1–December 31, 2020, which accounted for 2.7% of all cases during this period. Student case-patients increased rapidly after the start of the term, driven initially by cases and outbreaks in student accommodations. Case rates among students 18–23 years of age doubled at the start of term in towns with universities. Our findings highlight the need for face-to-face and control measures to reduce virus transmission

The potential for a concerted system for the rapid monitoring of excess mortality throughout Europe

We present the results of a survey conducted in the context of the project European Monitoring of Excess Mortality for Public Health Action (EuroMOMO), which is being conducted to develop a routine public health mortality monitoring system for the timely detection of excess deaths related to public health threats in Europe. The survey was conducted in 32 European countries using two questionnaires on: i) the existing and planned mortality monitoring systems, and ii) the routine collection of mortality data. Nine existing mortality monitoring systems were identified in seven countries (Belgium, Germany, France (two systems), Italy (two systems), Portugal, Spain, and Switzerland), as well as several systems that were in a pilot or planning state. Each system is described in detail. The results will be used for the subsequent phases of EuroMOMO, in particular for identifying the minimum requirements for the planned European system and for selecting countries to be included in the project's pilot phase.

Cost–benefit analysis of surveillance for surgical site infection following caesarean section

Objective To estimate the economic burden to the health service of surgical site infection following caesarean section and to identify potential savings achievable through implementation of a surveillance programme. Design Economic model to evaluate the costs and benefits of surveillance from community and hospital healthcare providers’ perspective. Setting England. Participants Women undergoing caesarean section in National Health Service hospitals. Main outcome measure Costs attributable to treatment and management of surgical site infection following caesarean section. Results The costs (2010) for a hospital carrying out 800 caesarean sections a year based on infection risk of 9.6% were estimated at £18,914 (95% CI 11,521 to 29,499) with 28% accounted for by community care (£5,370). With inflation to 2019 prices, this equates to an estimated cost of £5.0m for all caesarean sections performed annually in England 2018-19, approximately £1,866 and £93 per infection managed in hospital and community respectively. The cost of surveillance for a hospital for one calendar quarter was estimated as £3,747 (2010 costs). Modelling a decrease in risk of infection of 30, 20 or 10% between successive surveillance periods indicated that a variable intermittent surveillance strategy achieved higher or similar net savings than continuous surveillance. Breakeven was reached sooner with the variable surveillance strategy than continuous surveillance when the baseline risk of infection was 10 or 15% and smaller loses with a baseline risk of 5%. Conclusion Surveillance of surgical site infections after caesarean section with feedback of data to surgical teams offers a potentially effective means to reduce infection risk, improve patient experience and save money for the health service. Strengths and limitations • The model estimated both community (28%) and hospital costs (72%), providing a more representative estimate of overall economic burden to the health service. • Time-matching of patients with and without infection according to length of post-operative stay provided a more accurate assessment of excess bed-days attributable to surgical site infection (2.6 days) than average excess length of stay (median difference 5 days) comparison by disentangling the impact of prolonged length of stay on increased chance of detecting an infection. • Through capture and assessment of the costs and impact of surveillance, our model demonstrated the potential for savings through reductions in incidence of surgical site infections. • Costs were obtained from NHS National Schedule Reference Costs and other sources rather than observed expenditure and assumptions made about the number of extra midwife and general practitioner appointments resulting from infection. • The study was based on healthcare utilisation and did not assess direct and indirect costs borne by the patients or their carers

Mycobacterium chimaera

In their recent article, Svensson et al. provided results of an investigation into contamination of heater–cooler units (HCU) used in open-chest surgery with Mycobacterium chimaera in Denmark (1). We write to provide further information on the UK isolates included in their study

Standardization of Epidemiological Surveillance of Group A Streptococcal Impetigo

Impetigo is a highly contagious bacterial infection of the superficial layer of skin. Impetigo is caused by group A Streptococcus (Strep A) and Staphylococcus aureus, alone or in combination, with the former predominating in many tropical climates. Strep A impetigo occurs mainly in early childhood, and the burden varies worldwide. It is an acute, self-limited disease, but many children experience frequent recurrences that make it a chronic illness in some endemic settings. We present a standardized surveillance protocol including case definitions for impetigo including both active (purulent, crusted) and resolving (flat, dry) phases and discuss the current tests used to detect Strep A among persons with impetigo. Case classifications that can be applied are detailed, including differentiating between incident (new) and prevalent (existing) cases of Strep A impetigo. The type of surveillance methodology depends on the burden of impetigo in the community. Active surveillance and laboratory confirmation is the preferred method for case detection, particularly in endemic settings. Participant eligibility, surveillance population and additional considerations for surveillance of impetigo, including examination of lesions, use of photographs to document lesions, and staff training requirements (including cultural awareness), are addressed. Finally, the core elements of case report forms for impetigo are presented and guidance for recording the course and severity of impetigo provided

Severe Streptococcus pyogenes Infections, United Kingdom, 2003–2004

Epidemiology of severe disease caused by this organism has changed, with increased incidence and different risk groups