High-resolution spectroscopic subtyping of Staphylococcus aureus strains capable to study persistent bovine intramammary infections.

JOHLER, S; EHLING-SCHULZ, M; GRUNERT, T; BUZZOLA FR; STESSL B

Conferencia; 3rd International Conference Pathophysiology of Staphylococci; 2016

Staphylococcus aureus frequently causes chronic and persistent infections in humans as well as animals. Persistent S. aureus infections are difficult to treat and prone to resurgence. In order to develop treatment strategies to particularly combat persistent staphylococcal infections, novel diagnostic tools are needed that can be used to distinguish between those S. aureus strains that are more likely to persist and spread than others. Recently, we could demonstrate that metabolic fingerprinting by Fourier-transform infrared (FTIR) spectroscopy can discriminate between capsular polysaccharide (CP) expressing and non-expressing strains (Grunert et al. 2013), the latter were shown to be associated with persistence. We further aimed to assess the suitability of FTIR spectroscopy as a tool for S. aureus subtyping. FTIR spectral analysis resulted in high discriminatory power as obtained by PFGE and spa-typing, which is primarily based on the differential expression of capsular serotypes and/or additional surface glycopolymers rather than assignment to clonal complexes (Johler et al. 2016). Moreover, we applied this tool to follow S. aureus persistent intramammary infection in a dairy herd over years. Several distinct biotypes at individual and herd level could be identified, which showed typical phenotypic features associated with S. aureus persistence. In conclusion, we were able to demonstrate that FTIR spectroscopy offers high-resolution subtyping of S. aureus strains and provides phenotypic data on CP expression. Thus, FTIR spectroscopy may be particularly useful to identify S. aureus persistent strains and could also contribute to the better understanding of the role of surface glycopolymers in S. aureus pathogenicity.