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Additional file 1: Table S1. Primers used for O antigen serotyping. Figure S1. The number of P. aeruginosa isolates tested by each method. *Flagellin typing was not performed on 27 isolates from Duke University due to logistic constraints. Figure S2. Antibiotic resistance of isolates from Greece. Figure S3. The O-antigen profiles of representative non-typable P. aeruginosa isolates determined by SDS-PAGE. LPS from eight non-typable P.aeruginosa strains were extracted and separated on a 4���12% Bis-Tris SDS-polyacrylamide gel and stained with Pro-Q Emerald 300 according to manufacturer���s instructions. CandyCane glycoprotein molecular weight standard (ladder), P. aeruginosa strain PAK (+ve control).

Background: Phenol-soluble modulins (PSM) are amphipathic proteins produced by Staphylococcus aureus that promote virulence, inflammatory response, and biofilm formation. We previously showed that MRSA isolates from soft tissue infection (SSTI) produced significantly higher levels of PSM than MRSA isolates from hospital-acquired pneumonia (HAP) or infective endocarditis (IE). In this investigation, we sought to validate this finding in methicillin-susceptible S. aureus (MSSA) isolates. Methods: MSSA isolates (n = 162) from patients with SSTI, HAP, and IE were matched 1:1:1 based on geographic origin of the infection to form 54 triplets (North America n = 27, Europe n = 25, Australia n = 2). All isolates underwent spa typing and were classified using eGenomics. In vitro PSM production was quantified by high-performance liquid chromatography/mass spectrometry. Fischer's Exact Test and the Kruskal-Wallis test were used for statistical analysis. Results: Spa1 was more common in SSTI (14.81% SSTI, 3.70% HAP, 1.85% IE) (< 0.03). Spa2 was more common in HAP (0% SSTI, 12.96% HAP, 3.70% IE) (< 0.01). Levels of PSMα1-all differed significantly among the three clinical groups, with SSTI isolates producing the highest levels and IE producing the lowest levels of PSMα1-4. Spa1 isolates produced significantly more delta-toxin (< 0.03) than non-Spa1 isolates. No associations between PSM levels and clinical outcome of SSTI, HAP, or IE were identified. Conclusion: Production of PSMα1-is highest in SSTI MSSA isolates, supporting the hypothesis that these peptides are important for SSTI pathogenesis. These findings are similar to those described in MRSA, and demonstrate that associations between PSM levels and type of infection are independent of the methicillin-resistance status of the isolate.