Public Library of Science Acta Medica Okayama 1932-6203 14 5 2019 Staphylococcus aureus aggregation in the plasma fraction of silkworm hemolymph e0217517 EN Hiroki Ryuno Graduate School of Pharmaceutical Sciences, The University of Tokyo Fuki Nigo Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Isao Naguro Graduate School of Pharmaceutical Sciences, The University of Tokyo Kazuhisa Sekimizu Institute of Medical Mycology, Teikyo University Chikara Kaito Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University Staphylococcus aureus formed bacterial aggregates in the plasma fraction of the hemolymph of silkworm, the larva of Bombyx mori, in a growth-dependent manner. The addition of arabinose or galactose inhibited the formation of S. aureus aggregates in the silkworm plasma. Formation of the bacterial aggregates depended on S. aureus genes required for the synthesis of bacterial surface polysaccharides-ypfP and ltaA, which are involved in lipoteichoic acid synthesis, and the tagO gene, which is involved in wall teichoic acid synthesis. These findings suggest that S. aureus forms bacterial aggregates in the silkworm plasma via bacterial surface teichoic acids. No potential conflict of interest relevant to this article was reported.