References of "Telford, John"
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See detailCapsular Gene Typing of Streptococcus agalactiae Compared to Serotyping by Latex Agglutination
Yao, Kaihu; Poulsen, Knud; Maione, Domenico et al

in Journal of Clinical Microbiology (2012), 51(2), 503-507

We evaluated three different PCR-based capsular gene typing methods applied to 312 human and bovine Streptococcus agalac- tiae (group B Streptococcus [GBS]) isolates and compared the results to serotyping ... [more ▼]

We evaluated three different PCR-based capsular gene typing methods applied to 312 human and bovine Streptococcus agalac- tiae (group B Streptococcus [GBS]) isolates and compared the results to serotyping results obtained by latex agglutination. Among 281 human isolates 27% could not be typed by latex agglutination. All 312 isolates except 5 could be typed by the three PCR methods combined. Two of these methods were multiplex assays. Among the isolates that were typeable by both latex ag- glutination and capsular gene typing, 94% showed agreement between the two methods. However, each of the PCR methods showed limitations. One of the methods did not include all 10 recognized serotypes, one misidentified eight isolates of serotypes Ib and IV as serotype Ia, and one did not distinguish between serotypes VII and IX. For five isolates that showed aberrant pat- terns in the capsular gene typing, long-range PCR targeting the cps operon disclosed large insertions or deletions affecting the cps gene cluster. A sensitive flow cytometric assay based on serotype-specific antibodies applied to 76 selected isolates that were nontypeable by latex agglutination revealed that approximately one-half of these did express capsular polysaccharide. A proce- dure for convenient and reliable capsular gene typing to be included in epidemiological and surveillance studies of S. agalactiae is proposed. [less ▲]

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See detailNEONATAL INVASIVE GROUP B STREPTOCOCCAL (GBS) INFECTIONS IN EUROPE
MELIN, Pierrette ULg; Berner, Reinhard; Afshar, Baharak et al

Poster (2011, September)

Objectives: To describe clinical characteristics and capsular type of GBS isolates responsible of invasive infections in infants from Belgium, Bulgaria, Czech-Republic, Denmark, Germany, Italy, Spain and ... [more ▼]

Objectives: To describe clinical characteristics and capsular type of GBS isolates responsible of invasive infections in infants from Belgium, Bulgaria, Czech-Republic, Denmark, Germany, Italy, Spain and United Kingdom, representing one of the main objectives of the DEVANI (DEsign of a Vaccine Against Neonatal Infections) project. Methods: Surveillance of invasive GBS infections in infants was performed from mid-2008 through December 2010. For each case, a standardized case report form was filled. Samples from cases were processed using local procedures. GBS isolates were characterised in national central labs using standardised type-specific (Ia, Ib-IX) latex agglutination and molecular typing methods. Results: Data on 188 infants with invasive infection were analysed: 144 (60.6%) early onset diseases (EOD) and 74 (39.4%) late onset diseases (LOD). In EOD, mean/median ages at onset were 14/0 hours and the male:female ratio was 1.25. The predominant manifestation at onset was respiratory distress (42% cases); 83% cases were associated with sepsis/bacteremia, 15% with pneumonia and 6% with meningitis. Late-prenatal screening cultures were obtained from 51% of cases’ mothers and only half of these were positive for GBS. Non-elective C-section, intrapartum fever and rupture of membrane (>18h) were more frequent in EO-cases’ mothers versus healthy babies’ GBS-positive mothers. The major serotypes were III (43%), V (21%) and Ia (18%). In LOD, mean/median ages at onset were 42/34 days and the male:female ratio was 0.9. The predominant characteristic at onset was fever (62% cases); 70% cases were associated with sepsis and 30% with meningitis. Very rare manifestations were osteomyelitis and cellulitis. Serotype III was highly predominant (80.6%) followed mainly by Ia (12.5%). Death rates were 4.7/1.5% in EOD/LOD. Conclusions: Clinical presentations were associated with age at onset of infection. Serotype III predominated in neonatal infections. Prenatal screening was not universal neither sensitive. Study funded through the European Commission Seventh Framework. [less ▲]

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See detailInternational External Quality Assurance for Laboratory Identification and Typing of Streptococcus agalactiae (group B streptococci)
Afshar, Baharak; Broughton, Karen; Creti, Roberta et al

in Journal of Clinical Microbiology (2011)

We report the results from the first international multicentre external quality assessment (EQA) studies for molecular and serological typing of group B streptococcus (GBS) strains as part of DEVANI ... [more ▼]

We report the results from the first international multicentre external quality assessment (EQA) studies for molecular and serological typing of group B streptococcus (GBS) strains as part of DEVANI (DEsign of a Vaccine Against Neonatal Infections), a pan-European programme. A questionnaire-based surveillance was undertaken amongst eight DEVANI and six non-DEVANI participating laboratories from 13 countries in order to assess their current microbiological procedures for GBS screening, diagnosis and typing. GBS strains from three EQA distributions were characterised using molecular and serological methods based on GBS capsular polysaccharide typing. Participants were asked to test the first distribution using their current serotyping and genotyping methods. Strep-B-Latex agglutination method was the most widely used method with a typeability value of >90%. A multiplex PCR assay for GBS capsular gene typing was also used by two of 14 centres who achieved a typeability value of 93%; this assay only detected 9 of 10 GBS capsular polysaccharide genes. From the second and third EQA studies standardised protocols were prepared for serological and molecular typing of GBS strains based on the Strep-B-Latex agglutination method and a novel multiplex PCR assay which detected all ten GBS capsular types (Ia to IX). These standardised protocols are being used by many European laboratories and as the use of these methods increase, it is imperative to continuously improve and assess laboratory performance and offer training to any laboratories that have technical difficulties. [less ▲]

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