Distribution of capsular and surface polysaccharide serotypes of methicillin-resistant Staphylococcus aureus in Germany
Abstract number: p1817
von Eiff C., Taylor K.L., Fattom A.I., Peters G., Becker K.
Staphylococcus aureus is still one of the most feared pathogens because of his ability to cause serious infections, including overwhelming sepsis. Since 1961, the emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) has been documented in almost every continent and it is associated both with hospital and community-acquired infections. Although S. aureus has been found to express 13 capsular types, only two capsular polysaccharides (CPs), type 5 and type 8, comprise ca. 80% of infectious isolates. A renewed interest emerged following the observation that CPs are both essential virulence factors and putative protective antigens.
Four-hundred consecutive MRSA isolates were collected at 10 centres (max. 40 isolates per centre) as part of a multicentre study conducted throughout Germany in 2004. Isolates were collected from various sources, including colonization sites as well as infectious foci. Only one isolate per patient was included and all isolates were spa-genotyped. CPs were determined by slide agglutination with CP-specific antibodies (anti-T5-DT, anti-T8-conjugate, anti-336-rEPA). The serotypes were confirmed by immunodiffusion using lysostaphin-digested cell lysates.
In the present study, we serotyped MRSA isolates collected most recently in a German multicentre study. All 400 MRSA isolates evaluated were one of the serotypes tested, with 290 isolates being type 5 (72.5%), 44 isolates being type 8 (11%), and 66 isolates being type 336 (16.5%). The prevalence of capsular and surface polysaccharide serotypes varied greatly from centre to centre, with type 5 ranging from 5090% (type 8, 2.522.5% type 336, 7.5 35%). While serotype 336 was often associated with spa types 008 and 032 (as observed in different centres), high prevalence of this surface polysaccharide serotype was not due to a major outbreak in a single centre. Altogether, serotype 336 was detected in strains exhibiting 20 different spa types. Sorting by culture specimen source, type 336 was more common in airway-related specimens (e.g. swabs from anterior nares, throat and bronchial secretions).
CP serotyping of MRSA isolates from Germany show that the majority of isolates are comprised of serotypes 5. Of interest, type 336 strains are more common than type 8 strains, with one of six strains positive for type 336. The unexpected high prevalence of type 336 positive strains was not due to clonal spread.
|Session name:||XXIst ISTH Congress|
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