Staphylococcus aureus seroproteomes discriminate ruminant isolates causing mild or severe mastitis

Abstract

Staphylococcus aureus is a major cause of mastitis in ruminants. In ewe mastitis, symptoms range from subclinical to gangrenous mastitis. S. aureus factors or host-factors contributing to the different outcomes are not completely elucidated. In this study, experimental mastitis was induced on primiparous ewes using two S. aureus strains, isolated from gangrenous (strain O11) or subclinical (strain O46) mastitis. Strains induced drastically distinct clinical symptoms when tested in ewe and mice experimental mastitis. Notably, they reproduced mild (O46) or severe (O11) mastitis in ewes. Ewe sera were used to identify staphylococcal immunoreactive proteins commonly or differentially produced during infections of variable severity and to define core and accessory seroproteomes. Such SERological Proteome Analysis (SERPA) allowed the identification of 89 immunoreactive proteins, of which only 52 (58.4%) were previously identified as immunogenic proteins in other staphylococcal infections. Among the 89 proteins identified, 74 appear to constitute the core seroproteome. Among the 15 remaining proteins defining the accessory seroproteome, 12 were specific for strain O11, 3 were specific for O46. Distribution of one protein specific for each mastitis severity was investigated in ten other strains isolated from subclinical or clinical mastitis. We report here for the first time the identification of staphylococcal immunogenic proteins common or specific to S. aureus strains responsible for mild or severe mastitis. These findings open avenues in S. aureus mastitis studies as some of these proteins, expressed in vivo, are likely to account for the success of S. aureus as a pathogen of the ruminant mammary gland.

Genome Sequences of Two Staphylococcus aureus Ovine Strains That Induce Severe (Strain O11) and Mild (Strain O46) Mastitis

“…We characterized two S. aureus ovine strains, which were shown to be clonally related (9) and reproducibly induced severe (strain O11) and mild (strain O46) mastitis in experimental ewe mastitis (8).…”

Serological proteome analysis of Corynebacterium pseudotuberculosis isolated from different hosts reveals novel candidates for prophylactics to control caseous lymphadenitis

“…Similarly, Cphp4 and Cphp7 presented conserved HtaA domains found in secreted proteins involved in iron uptake and transport (Drazek et al, 2000). As shown for S. aureus in mastitis (Le Maré chal et al, 2011), it seems that C. pseudotuberculosis expresses proteins related to iron acquisition and metabolism in the CLA context.…”

“…Pellets were solubilized in sample solution containing 7 M urea, 2 M thio-urea, 25 mM dithiothreitol (DTT), 4% (w/v) 3-[(3-cholamidopropyl)dimethylammonio]-1-propane-sulfonate (CHAPS), and 2% (w/v) ampholyte containing buffer (IPG-Buffer 3-10 NL, GE Healthcare, Orsay, France). Isoelectric focusing was carried out using 18 cm Immobiline Dry Strips on a Multiphor II electrophoresis system (Amersham Biosciences) using a standard procedure described previously (Le Maré chal et al, 2011). The second dimensional separation was performed using a 12% polyacrylamide gel without stacking on an Ettan TM DALTtwelve electrophoresis system (GE Healthcare) in TrisGlycine-SDS buffer at 180 V for 9 h. The gels were stained with colloidal Coomassie blue and then cleared with an aqueous solution containing 10% acetic acid and 30% methanol.…”

“…Finally, the membranes were washed in ultrapure water, scanned with an Image Scanner II (Amersham Biosciences), and analyzed using Image-Quant (GE-Healthcare) software. Immune-reactive proteins were identified using Nano-ESI-MS/MS and the MASCOT software package as described previously (Seyffert et al, 2012;Le Maré chal et al, 2011). Briefly, for each protein identified in NanoLC-ESI-MS/MS, a minimum of four peptides with MASCOT score corresponding to a P value below 0.05 or an exponentially modified protein abundance index greater (Ishihama et al, 2005) than 0.4 were necessary for validation with a high degree of confidence.…”

“…However, the search for potential prophylactic candidates should also consider proteins of the pathogen proteome that are capable of stimulating the host immune response (Bhavsar et al, 2007). To this end, some studies have employed the serological proteome analysis (SERPA) to detect and identify immune-reactive proteins (i.e., proteins that are recognized by the serum of infected animals and thus produced during the infection) in search for information on pathogen biology and the host immune response to infection by bacteria (Le Maré chal et al, 2011;Seyffert et al, 2012). The SERPA approach has allowed the identification of six C. pseudotuberculosis 1002 exoproteins related to dormancy, colonization, and microbial metabolite transport .…”