| 1. |
- Asteberg, Inger, et al.
(author)
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A food-borne streptococcal sore throat outbreak in a small community.
- 2006
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In: Scandinavian journal of infectious diseases. - : Informa UK Limited. - 0036-5548 .- 1651-1980. ; 38:11-12, s. 988-94
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Journal article (peer-reviewed)abstract
- Beta-haemolytic group A streptococci (GAS) is a common cause of sore throat, usually spread person-to-person. Outbreaks related to infected food have more seldom been reported. The bacteria may originate from the throat or from wounds on the hands of persons handling the food. An outbreak in Sätila, Sweden, in April/May 2003 involving 153 individuals who fell ill after eating contaminated 'sandwich-layer cakes' was investigated in a descriptive, retrospective cohort study. Questionnaires were distributed, one immediately after the outbreak and one 3 months later. The average attack rate was 72%. 143 individuals sought medical care and 137 were treated with antibiotics. 76 individuals were ill for more than 4 days. GAS isolates of identical T-type were obtained from the throats of the patients, wounds on the caterer's fingers and also from the cakes. PFGE banding patterns of 14 representative isolates were identical, as well as the emm-sequence type, emm 89, of 3 chosen isolates. The study shows that GAS from a small wound on a finger can cause illness in a large number of individuals. To prevent further outbreaks, it is important to increase public awareness of this type of transmission.
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| 2. |
- Browall, Sarah, et al.
(author)
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Clinical manifestations of invasive pneumococcal disease by vaccine and non-vaccine types
- 2014
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In: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 44:6, s. 1646-1657
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Journal article (peer-reviewed)abstract
- Pneumococcal conjugated vaccines (PCVs) have shown protection against invasive pneumococcal disease by vaccine serotypes, but an increase in non-vaccine serotype disease has been observed. Type-specific effects on clinical manifestation need to be explored.Clinical data from 2096 adults and 192 children with invasive pneumococcal disease were correlated to pneumococcal molecular serotypes. Invasive disease potential for pneumococcal serotypes were calculated using 165 invasive and 550 carriage isolates from children.The invasive disease potential was lower for non-PCV13 compared to vaccine-type strains. Patients infected with non-PCV13 strains had more underlying diseases, were less likely to have pneumonia and, in adults, tended to have a higher mortality. Furthermore, patients infected with pneumococci belonging to clonal serotypes only expressing non-PCV13 capsules had a higher risk for septicaemia and mortality.PCV vaccination will probably lead to a decrease in invasive pneumococcal disease but an alteration in the clinical manifestation of invasive pneumococcal disease. Genetic lineages causing invasive pneumococcal disease in adults often express non-vaccine serotypes, which can expand after vaccination with an increased risk of infection in patients with underlying diseases.
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| 3. |
- Darenberg, Jessica, et al.
(author)
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Molecular and clinical characteristics of invasive group A streptococcal infection in Sweden
- 2007
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In: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1537-6591 .- 1058-4838. ; 45:4, s. 8-450
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Journal article (peer-reviewed)abstract
- Background. The incidence and severity of invasive group A streptococcal infection demonstrate great variability over time, which at least, in part, seems to be related to group A streptococcal type distribution among the human population. Methods. An enhanced surveillance study of invasive group A streptococcal infection (746 isolates) was performed in Sweden from April 2002 through December 2004. Noninvasive isolates from either the throat or skin (773 isolates) were collected in parallel for comparison. Clinical and epidemiological data were obtained from 88% of patients with invasive disease and were related to isolate characteristics, including T type, emm sequence type, and the presence of 9 superantigen genes, as well as pulsed-field gel electrophoresis pattern comparisons of selected isolates. Results. The annual incidence was 3.0 cases per 100,000 population. Among the patients with invasive disease, 11% developed streptococcal toxic shock syndrome, and 9.5% developed necrotizing fasciitis. The overall case-fatality rate was 14.5%, and 39% of the patients with streptococcal toxic shock syndrome died (P < .001). The T3/13/B3264 cluster accounted for 33% of invasive and 25% of noninvasive isolates. Among this most prevalent type cluster, emm types 89 and 81 dominated. Combined results from pulsed-field gel electrophoresis, emm typing, and superantigen gene profiling identified subgroups within specific emm types that are significantly more prone to cause invasive disease than were other isolates of the same type. Conclusions. This study revealed a changing epidemiology of invasive group A streptococcal infection in Sweden, with emergence of new emm types that were previously not described. The results also suggest that some clones may be particularly prone to cause invasive disease.
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| 4. |
- Darenberg, Jessica
(author)
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Streptococcus pyogenes infections and toxic shock syndrome : molecular epidemiology and immunotherapy
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Streptococcus pyogenes, also known as group A streptococcus (GAS), is an important human pathogen causing a wide variety of diseases. One of the most severe diseases is streptococcal toxic shock syndrome (STSS), which is associated with high mortality rates. Toxic shock syndrome (TSS) may also be caused by Staphylococcus aureus. Superantigens have been identified as key mediators of STSS and staphylococcal TSS. Intravenous polyspecific immunglobulin (IVIG) has been suggested as adjunctive therapy in TSS, since it contains neutralising antibodies against streptococcal and staphylococcal superantigens, as well as bacterial opsonising antibodies. To assess the safety and efficacy of IVIG as adjunctive therapy in STSS, we conducted a multicenter placebo-controlled trial (paper I). The trial was prematurely terminated due to a low incidence of disease in the participating countries. Results were obtained from 21 enrolled patients; 10 of whom received IVIG and 11 placebo. The primary objective was mortality over 28 days, and a trend to decreased mortality was observed in the IVIG group, 10% versus 36% in the placebo group. A significant decrease in sepsis-related organ failure assessment (SOFA) score was noted in the IVIG-group, whereas no change was seen in the placebo group. The IVIG cases obtained a significantly increased plasma superantigen-neutralising activity against their own isolate following IVIG administration, whereas no change could be noted among patients in the placebo group. In paper II we tested whether superantigen-containing culture supernatants from streptococcal and staphylococcal severe sepsis isolates were inhibited to an equal extent by IVIG. Three different IVIG preparations were tested and found to be highly efficient in neutralising the superantigens. Most supernatants were completely inhibited at concentrations between 0.5 - 2.5 mg IVIG/ml. Importantly, culture supernatants from S. pyogenes isolates were consistently inhibited to a higher extent as compared to those of S. aureus isolates. In paper III and IV, results from active surveillance of invasive GAS infections in Denmark and Sweden during 2001-02 and 2002-04, respectively, are described. The yearly incidences were similar, 2.0-3.4 /100 0000 inhabitants, as was the prevalence of the severe manifestations STSS and necrotising fasciitis (NF), which were seen in approximately 10% of the cases. However, differences were observed in outcome with a mortality rate of 25% and 14.5% in Denmark and Sweden, respectively. Also the GAS type distribution varied between the two studies. emm1 was the most prevalent type (32%) in the Danish study in comparison to the new types emm89 (16%) and 81 (14%) that dominated in the Swedish study. Non-invasive GAS isolates were collected and analysed in parallel with the invasive in both studies, and the type distribution differed significantly from the invasive isolates. Differences in presence of superantigen genes were seen between isolates of different emm-types and also between invasive and non-invasive isolates. A combination of PFGE-analysis and superantigen profiling revealed subclones within the emm-types with higher invasiveness than others (paper IV). Further, IVIG treatment in patients with STSS was significantly associated with improved outcome. 20 out of 72 patients with STSS were given IVIG, with a mortality of 15% as compared to 48% among patients not receiving IVIG (paper IV). This thesis provides further support of IVIG therapy in STSS, and the in vitro analyses revealed that a higher dose of IVIG may be needed in staphylococcal TSS in order to achieve protective antibody levels. The thesis also provides new insights in the molecular epidemiology of invasive GAS disease.
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| 5. |
- Lamagni, Theresa L, et al.
(author)
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Epidemiology of severe Streptococcus pyogenes disease in Europe.
- 2008
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In: Journal of Clinical Microbiology. - 1098-660X. ; 46:7, s. 2359-2367
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Journal article (peer-reviewed)abstract
- The past two decades have brought worrying increases in severe Streptococcus pyogenes diseases globally. To investigate and compare the epidemiological patterns of these diseases within Europe, data on severe S. pyogenes infections were collected through an EU FP-5 funded programme (Strep-EURO). Prospective population-based surveillance of severe S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in eleven countries across Europe (Cyprus, Czech Republic, Denmark, Finland, France, Germany, Greece, Italy, Romania, Sweden, UK) using a standardised case definition. A total of 5522 cases of severe S. pyogenes infection were identified across the eleven countries during this period. Rates of reported infection varied, reaching 3/100,000 population in the northern European countries. Seasonal patterns of infections showed remarkable congruence between countries. Risk of infection was highest among the elderly, with rates being higher in males than females in most countries. Skin lesions/wounds were the most common predisposing factor, reported in 25% of cases; 21% had no predisposing factors reported. Skin and soft tissue was the most common focus of infection, 32% of patients having cellulitis and 8% necrotizing fasciitis. The overall 7-day case fatality rate was 19%, 44% among cases who developed streptococcal toxic shock syndrome. Findings from Strep-EURO confirm a high incidence of severe S. pyogenes disease in Europe. Furthermore, these results have identified targets for public health intervention, as well as raising awareness of severe S. pyogenes disease across Europe.
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| 6. |
- Lefrancq, Noemie, et al.
(author)
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Global spatial dynamics and vaccine-induced fitness changes of Bordetella pertussis
- 2022
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In: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 14:642
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Journal article (peer-reviewed)abstract
- As with other pathogens, competitive interactions between Bordetella pertussis strains drive infection risk. Vaccines are thought to perturb strain diversity through shifts in immune pressures; however, this has rarely been measured because of inadequate data and analytical tools. We used 3344 sequences from 23 countries to show that, on average, there are 28.1 transmission chains circulating within a subnational region, with the number of chains strongly associated with host population size. It took 5 to 10 years for B. pertussis to be homogeneously distributed throughout Europe, with the same time frame required for the United States. Increased fitness of pertactin-deficient strains after implementation of acellular vaccines, but reduced fitness otherwise, can explain long-term genotype dynamics. These findings highlight the role of vaccine policy in shifting local diversity of a pathogen that is responsible for 160,000 deaths annually.
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| 7. |
- Lindstrand, Ann, et al.
(author)
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Pneumococcal Carriage in Children under Five Years in Uganda-Will Present Pneumococcal Conjugate Vaccines Be Appropriate?
- 2016
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In: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:11
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Journal article (peer-reviewed)abstract
- BACKGROUND: Pneumonia is the major cause of death in children globally, with more than 900,000 deaths annually in children under five years of age. Streptococcus pneumoniae causes most deaths, most often in the form of community acquired pneumonia. Pneumococcal conjugate vaccines (PCVs) are currently being implemented in many low-income countries. PCVs decrease vaccine-type pneumococcal carriage, a prerequisite for invasive pneumococcal disease, and thereby affects pneumococcal disease and transmission. In Uganda, PCV was launched in 2014, but baseline data is lacking for pneumococcal serotypes in carriage.OBJECTIVES: To study pneumococcal nasopharyngeal carriage and serotype distribution in children under 5 years of age prior to PCV introduction in Uganda.METHODS: Three cross-sectional pneumococcal carriage surveys were conducted in 2008, 2009 and 2011, comprising respectively 150, 587 and 1024 randomly selected children aged less than five years from the Iganga/Mayuge Health and Demographic Surveillance Site. The caretakers were interviewed about illness history of the child and 1723 nasopharyngeal specimens were collected. From these, 927 isolates of S. pneumoniae were serotyped.RESULTS: Overall, the carriage rate of S. pneumoniae was 56% (957/1723). Pneumococcal carriage was associated with illness on the day of the interview (OR = 1.50, p = 0.04). The most common pneumococcal serotypes were in descending order 19F (16%), 23F (9%), 6A (8%), 29 (7%) and 6B (7%). One percent of the strains were non-typeable. The potential serotype coverage rate for PCV10 was 42% and 54% for PCV13.CONCLUSION: About half of circulating pneumococcal serotypes in carriage in the Ugandan under-five population studied was covered by available PCVs.
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| 8. |
- Linner, Anna, et al.
(author)
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Clinical Efficacy of Polyspecific Intravenous Immunoglobulin Therapy in Patients With Streptococcal Toxic Shock Syndrome : A Comparative Observational Study
- 2014
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In: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1058-4838 .- 1537-6591. ; 59:6, s. 851-857
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Journal article (peer-reviewed)abstract
- Background. Streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis are the 2 most severe invasive manifestations caused by group A Streptococcus (GAS). Intravenous immunoglobulin (IVIG) therapy has been suggested as adjunctive treatment with a beneficial effect on mortality. However the clinical evidence is limited. Here we aim to further document the clinical efficacy of administered IVIG therapy in a comparative observational study of well-defined patients with STSS. Methods. The effect of IVIG was evaluated in patients with STSS prospectively identified in a nationwide Swedish surveillance study conducted between April 2002 and December 2004. Detailed data on symptoms, severity of disease, treatment, and outcome were obtained from 67 patients. Crude and adjusted analyses with logistic regression were performed. Results. Twenty-three patients received IVIG therapy compared with 44 who did not. No significant difference in comorbidities, severity of disease, organ failures, or sex was seen, but the IVIG group was slightly younger and had a higher degree of necrotizing fasciitis (56% vs 14%). The primary endpoint was 28-day survival. Adjusted analysis revealed that factors influencing survival in STSS were Simplified Acute Physiology Score II (odds ratio [OR], 1.1; P = .007), clindamycin (OR, 8.6; P = .007), and IVIG (OR, 5.6; P = .030). Conclusions. This comparative observational study of prospectively identified STSS patients demonstrates that both IVIG and clindamycin therapy contribute to a significantly improved survival in STSS.
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| 9. |
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| 10. |
- Luca, Bogdan, et al.
(author)
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Clinical and Microbiological Characteristics of Severe Streptococcus pyogenes Disease in Europe.
- 2009
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In: Journal of Clinical Microbiology. - 1098-660X. ; 47, s. 1155-1165
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Journal article (peer-reviewed)abstract
- In an attempt to compare the epidemiology of severe S. pyogenes infection within Europe, prospective data were collected through the Strep-EURO programme. Surveillance of severe S. pyogenes infection diagnosed during 2003 and 2004 was undertaken in eleven countries across Europe using a standardised case definition and questionnaire. Patient data as well as bacterial isolates were collected and characterized by T- and, M/emm-typing and selected strains were analysed for presence of superantigen genes. Data were analysed to compare the clinical and microbiological patterns of infections across participating countries. Totally 4353 isolates were collected from 5521 cases with severe S. pyogenes infection identified. It was wide diversity of M/emm-types (104) found among the S. pyogenes clinical isolates but M/emm-type distribution varied broadly between participating countries. The ten most predominant M/emm-types were 1, 28, 3, 89, 87, 12, 4, 83, 81, and 5 in descending order. A correlation was found between some specific disease manifestation, age of patients and emm-types. Streptococcal toxic shock syndrome and necrotizing fasciitis, although caused by a large number of types, were particularly associated with M/emm-types 1 and 3. The emm-types included in the 26-valent vaccine under development, were generally well represented in the presentmaterial; 16 of the vaccine types accounted for 69% of isolates. The Strep-EURO collaborative programme has contributed to enhance the knowledge on the spread of invasive disease caused by S. pyogenes within Europe and encourage future surveillance with notification of cases and characterisation of strains, important for vaccine strategies and other health care issues.
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