Nationwide laboratory-based surveillance of invasive beta-haemolytic streptococci in Denmark from 2005 to 2011.

The aim of this work was to describe national surveillance of invasive beta-haemolytic streptococci (BHS) in Denmark and to report overall trends and major findings by groups and types of BHS causing laboratory-confirmed disease from 2005 to 2011. A total of 3063 BHS isolates were received from 2872 patients. Based on confirmed cases the overall annual incidence increased from 6.2 to 8.9 per 100 000 persons between 2005 and 2011. In 2011 the incidences of group A, B, C and G streptococci were 3.1, 2.3, 0.9 and 2.6 per 100 000 persons, respectively. An increase was observed for all groups of BHS, but in particular for group G in men above 65 years of age. Among group A streptococci (GAS), five T-types (1, 28,12, 3,13,B3264 and B3264) represented 71% and five emm-types (1, 28, 3, 89 and 12) 76% of all isolates. Among group B streptococci (GBS) four types (III, Ia, V, Ib) represented 79% of the isolates. Potential coverage for future vaccines against GAS and GBS disease was 76% compared with the 26-valent GAS vaccine and 89% based on GBS serotypes Ia, Ib, II, III and V. The number of reported cases of invasive BHS disease increased in Denmark from 2005 to 2011. Nationwide laboratory-based surveillance of BHS is required to monitor epidemiological changes, explore potential outbreaks and determine potential vaccine coverage.

Variation at the capsule locus, cps, of mistyped and non-typable Streptococcus pneumoniae isolates.

The capsule polysaccharide locus (cps) is the site of the capsule biosynthesis gene cluster in encapsulated Streptococcus pneumoniae. A set of pneumococcal samples and non-pneumococcal streptococci from Denmark, the Gambia, the Netherlands, Thailand, the UK and the USA were sequenced at the cps locus to elucidate serologically mistyped or non-typable isolates. We identified a novel serotype 33B/33C mosaic capsule cluster and previously unseen serotype 22F capsule genes, disrupted and deleted cps clusters, the presence of aliB and nspA genes that are unrelated to capsule production, and similar genes in the non-pneumococcal samples. These data provide greater understanding of diversity at a locus which is crucial to the antigenic diversity of the pathogen and current vaccine strategies.

A report of Streptococcus pneumoniae serotype 6D in Europe.

Serotype 6D of Streptococcus pneumoniae has been reported in Asia and the Fijian islands among nasopharyngeal carriage isolates. We now report a 6D isolate from a Finnish adult with invasive pneumococcal disease. Interestingly, the Finnish isolate and Asian isolate capsule gene loci are almost identical.

The International Circumpolar Surveillance interlaboratory quality control program for Streptococcus pneumoniae, 1999 to 2008.

The International Circumpolar Surveillance (ICS) Program was initiated in 1999 to conduct population-based surveillance for invasive pneumococcal disease in select regions of the Arctic. An interlaboratory quality control (QC) program for pneumococcal serotyping and antibiotic susceptibility testing was incorporated into ICS by reference laboratories in northern Canada (Laboratoire de Santé Publique du Québec [LSPQ] in Sainte-Anne de Bellevue, Québec; National Centre for Streptococcus [NCS] in Edmonton, Alberta) and Alaska (Arctic Investigations Program [AIP]). The World Health Organization's Collaborating Centre for Reference and Research on Pneumococci at the Statens Serum Institute (SSI) in Copenhagen, Denmark, joined the QC program in 2004. The Iceland Reference Laboratory (IRL) in Reykjavik, Iceland, joined the QC program in 2006, but due to small sample sizes, data from IRL are not included in this report. From 1999 through 2008, 190 isolates were distributed among four laboratories (AIP, NCS, LSPQ, and SSI). The overall serotype concordance was 95.8%, and the overall serogroup concordance was 97.4%. The overall modal MIC concordance for testing by broth microdilution (BMD) and agar dilution was >96% for all the antibiotics except erythromycin (92.1%) and clindamycin (89.5%). MIC comparisons between the Etest and BMD resulted in lower concordance for erythromycin (73.9%), clindamycin (65.5%), and trimethoprim-sulfamethoxazole (80%); however, categorical concordance (susceptible, resistant) remained high at 98.6%, 89.1%, and 90.9%, respectively. Our data demonstrate a high degree of correlation of serotyping and antimicrobial susceptibility testing results between four participating laboratories.

Characterisation of invasive group B streptococci from adults in Denmark 1999 to 2004.

The aim of this study was to characterise the group B streptococci (GBS) isolates causing severe invasive infections in patients >15 years of age in Denmark from 1999 to 2004. A total of 411 invasive GBS isolates were phenotypically characterised by the capsular polysaccharide (CPS) serotype and protein Calpha, Cbeta and R4. The incidence of invasive GBS disease ranged from 2.2 to 3.2 per 100,000 adults in the study period, being highest among adults over 65 years of age. Diabetes was observed in 15% of the cases, 12% had alcohol abuse and 7% had cancer. Of all isolates, 77% were CPS serotypes Ia, Ib, III or V. The surface proteins Calpha or R4 were detected as the only protein in 57% of the GBS isolates. Cbeta was detected in 12% of the isolates, but always in combination with either Calpha or both Calpha and R4. The incidence of invasive GBS infections continued to increase in Denmark from 1999 to 2004. In that period, the overall case fatality was 14%. The most prevalent CPS serotypes were serotypes III, Ia, V and Ib. The most prevalent surface protein was R4 when testing for R4, Calpha and Cbeta. There was no clear relation between the GBS phenotype and infections with fatal outcome.

Morbidity, mortality and spatial distribution of meningococcal disease, 1974-2007.

To identify determinants for mortality and sequelae and to analyse the spatial distribution of meningococcal disease, we linked four national Danish registries. In the period 1974-2007, 5924 cases of meningococcal disease were registered. Our analysis confirms known risk factors for a fatal meningococcal disease outcome, i.e. septicaemia and high age (>50 years). The overall case-fatality rate was 7.6%; two phenotypes were found to be associated with increased risk of death; C:2a:P1.2,5 and B:15:P1.7,16. B:15:P1.7,16 was also associated with excess risk of perceptive hearing loss. The incidence rates of meningococcal disease were comparable between densely and less densely populated areas, but patients living further from a hospital were at significantly higher risk of dying from the infection. To improve control of meningococcal disease, it is important to understand the epidemiology and pathogenicity of virulent 'successful clones', such as C:2a:P1.2,5 and B:15:P1.7,16, and, eventually, to develop vaccines against serogroup B.

Outbreak of group A streptococcal throat infection: don't forget to ask about food.

We report a large foodborne outbreak due to group A streptococci (GAS), which caused acute tonsillo-pharyngitis in 200-250 patrons of a company canteen in Copenhagen, Denmark, in June 2006. A retrospective cohort study of canteen users showed that consumption of cold pasta was associated with an increased risk of illness (attack rate 68%, risk ratio 4.1, P<0.0001). Indistinguishable GAS strains (emm89, T-type 3/13/B3264) were cultured from three cases and a cook, who had prepared the pasta. To our knowledge, pasta has previously only twice been incriminated as the source of a GAS outbreak. Only six foodborne GAS outbreaks have been reported in Europe since 1970, four of them in Sweden or Denmark. This geographical clustering suggests that foodborne GAS outbreaks are probably under-recognized elsewhere.