| 1. |
- Darenberg, Jessica, et al.
(författare)
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Molecular and clinical characteristics of invasive group A streptococcal infection in Sweden
- 2007
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Ingår i: Clinical Infectious Diseases. - : Oxford University Press (OUP). - 1537-6591 .- 1058-4838. ; 45:4, s. 8-450
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Tidskriftsartikel (refereegranskat)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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| 2. |
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| 3. |
- Jasir, Aftab
(författare)
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Group A Streptococci; Epidemiology and Genetics of Antibiotic Resistance
- 2001
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Group A streptococci (GAS) cause throat and skin infections, severe invasive diseases as well as the non-suppurative complications acute rheumatic fever and glomerulonephritis. GAS have retained susceptibility to betalactam drugs, but resistance to alternative antibiotics is of concern. In a large Iranian survey the carrier rates among symptom-free children and those with pharyngotonsillitis were 20% and 34%, respectively. There were no macrolide resistant strains, but 42% were tetracycline resistant; of these, 406 isolates were typed by different methods. Though half of the strains were T- and M-nontypeable, more than 20 M types were represented. Non-typeable strains could mostly be typed genetically by a PCR-capture-ELISA procedure. Fingerprinting by PFGE disclosed further strain heterogeneity, suggesting tetracycline resistance to be disseminated among Iranian GAS strains. Among Swedish isolates from 1980-99, a new, non-inducible (NI) resistance phenotype, due to efflux was predominant during the 80ies. Classical MLS resistance, both inducible (IR) and constitutive (CR), seemed to appear only during the late 90-ies. In addition, three novel subphenotypes of MLS resistance were demonstrated. Resistance determinants were traced by PCR and invariably showed ermB in IR and CR strains but mefA in NI strains. Novel subphenotype strains mostly showed both erm and mef genes. Most IR strains were also tetracycline resistant, and typing of 100 such strains serologically as well as by PCR-capture-ELISA and emm-sequencing showed almost all to be of M-type 77, not previously reported from Sweden. In addition, five different clones of such multi-resistant strains were distinguished by PFGE. Thus, new molecular methods represent potent tools for epidemiological typing of antibiotic resistant and other GAS.
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| 4. |
- Jasir, Aftab, et al.
(författare)
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New antimicrobial peptide active against Gram-positive pathogens
- 2004
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Ingår i: Indian Journal of Medical Research. - 0971-5916. ; 119:Suppl., s. 74-76
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Tidskriftsartikel (refereegranskat)abstract
- Background & objectives: Human and animal cystatins have been shown to inhibit the replication of certain viruses and bacteria, though it is not directly demonstrated that the effects are due to protease inhibitory capacity of the cystatins. We report antibacterial properties of a novel antimicrobial peptidyl derivative, (2S)-2-(N-alpha-benzyloxycarbonyl-arginyl-leucylamido)-1-(E)-cinnamoyla mido-3-methylbutane, structurally based upon the aminoterminal segment of the inhibitory centre of the human cysteine protease inhibitor, cystatin C. Methods: Clinical isolates of group A, B, C and G streptococci were collected. The antibacterial activity of Cystapep 1 derivative was tested by agar well diffusion method. Results: Cystapep 1, displayed antibacterial activity against several clinically important Gram-positive bacteria. It displayed minimal inhibitory and bactericidal concentrations of about 16 mug/ml for both Staphylococcus aureus and Streptococcus pyogenes. In radial agar diffusion assays, groups A, B, C and G streptococci as well as staphylococci were generally susceptible to the action of Cystapep 1, whereas pneumococci and enterococci were less susceptible. No activity against Gram-negative bacteria was observed. Interpretation & conclusion: Cystapep 1 also showed high activity against methicillin-resistant Staph. aureus (MRSA) and multi-antibiotic resistant coagulase negative staphylococci (CNS), suggesting its mechanism of action to be different from most currently used antibiotics.
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| 5. |
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| 6. |
- Lamagni, Theresa L, et al.
(författare)
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Epidemiology of severe Streptococcus pyogenes disease in Europe.
- 2008
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Ingår i: Journal of Clinical Microbiology. - 1098-660X. ; 46:7, s. 2359-2367
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Tidskriftsartikel (refereegranskat)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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| 7. |
- Luca, Bogdan, et al.
(författare)
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Clinical and epidemiological aspects of invasive Streptococcus pyogenes infections in Denmark during 2003 and 2004
- 2008
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Ingår i: Journal of Clinical Microbiology. - 1098-660X. ; 46:1, s. 79-86
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Tidskriftsartikel (refereegranskat)abstract
- Active surveillance of invasive group A streptococcal (GAS) infections was conducted in Denmark during 2003 and 2004 as a part of the Strep-EURO initiative. The main objective was to improve understanding of the epidemiology of invasive GAS disease in Denmark. During the 2 years, 278 cases were reported, corresponding to a mean annual incidence of 2.6 cases per 100,000 inhabitants. The vast majority of isolates, 253 (91%), were from blood, with the remaining 25 (9%) being from cerebrospinal fluid, joints, or other normally sterile sites. The mean case fatality rate (CFR) was 20%, with the rate being higher in patients more than 70 years of age (36.5%). For streptococcal toxic shock syndrome (STSS) and necrotizing fasciitis the CFRs were 53% and 25%, respectively. Out of 16 T types recorded, three predominated: T28 (23%), T1 (22%), and the cluster T3/13/B3264 (14%). Among 29 different emm types, emm28 and emm1 accounted for 51% of strains, followed by emm3 (11%), emm89 (7%), and emm12 (5.5%). Low resistance rates were detected for macrolide-lincosamide-streptogramin B (MLSB) antibiotics (3%) and tetracycline (8%); two isolates exhibited coresistance to tetracycline and macrolides. Of nine pyrogenic exotoxin (superantigen) genes examined, speA and speC were identified in 58% and 40% of the strains, respectively; either of the genes was present in all strains causing STSS. Most strains harbored speG (99%). ssa was present in 14% of the isolates only. In Denmark, as in comparable countries, GAS invasive disease shows a sustained, high endemicity, with involvement of both established and emerging streptococcal emm and T types.
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| 8. |
- Luca, Bogdan, et al.
(författare)
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Clinical and Microbiological Characteristics of Severe Streptococcus pyogenes Disease in Europe.
- 2009
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Ingår i: Journal of Clinical Microbiology. - 1098-660X. ; 47, s. 1155-1165
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Luca, Bogdan, et al.
(författare)
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Molecular characterization of invasive and non-invasive Streptococcus pyogenes isolates from Romania.
- 2008
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Ingår i: Journal of Medical Microbiology. - : Microbiology Society. - 0022-2615 .- 1473-5644. ; 57:Pt 11, s. 1354-1363
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Tidskriftsartikel (refereegranskat)abstract
- In 2002, the Romanian National Reference Laboratory was invited to join the Strep-EURO project to study invasive Streptococcus pyogenes infections. During 2003 and 2004, a total of 33 isolates recovered from invasive disease were received from eight Romanian counties. For comparison, 102 isolates from non-invasive disease, as well as a collection of 12 old invasive strains (isolated between 1967 and 1980) were included. All isolates were characterized by several methods: T and emm typing, presence of the fibronectin-binding protein F1 gene (prtF1), serum opacity factor (sof), and superantigen (SAg) genes (speA, speB, speC, speF, speG, speH, ssa and smeZ). The recent invasive isolates exhibited 19 emm-types, of which emm1, emm81, emm76, emm49 and emm78 covered 57 % of the strains. Furthermore, multilocus sequence typing analysis revealed nine new sequence types, corresponding to emm types 1, 12, 49, 81, 92, 100, 106 and 119. The non-invasive isolates comprised 24 different emm types with a predominance of emm1 and 12; the old invasive strains were of eight emm types, of which four were unique for this group. All isolates harboured speB and speF; smeZ was detected in all invasive strains, except for the emm49 and emm81 isolates. The majority of isolates from carriers, and patients with pharyngitis were prtF1 positive, most of these (14 strains) being emm12. High tetracycline resistance rates were noted among both invasive and control isolates (54 % and 35 %, respectively), whereas macrolide resistance rates were low (3 % and 5 %, respectively). Active and continuing surveillance is required to provide an accurate assessment of the disease burden and to provide epidemiological data on the character of isolates in Romania.
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