[ODP21] 5. Pathogenicity -a. Adhesins and colonization factors

[ODP-108] Appearance of phage-like, filamentous aggregate, and pilus structures on the surface of CA-MRSA/J

Tsai-Wen Wan^1,2, Wei-Chun Hung^1,3, Lee-Jene Teng², Tatsuo Yamamoto¹ (¹Dept. Epidemiol. Genomics Evol., Intl. Med. Edu. Res. Center, ²National Taiwan Univ., Col. Med., ³Kaohsiung Med. Univ.)

Regarding community-associated methicillin-resistant Staphylococcus aureus, with genotype ST8/SCCmecIVl (CA-MRSA/J), which emerged in Japan, we demonstrated: (i) invasive/adherent pathotypes, (ii) the spj gene, encoding a large, highly variable cell-wall anchored protein, and (iii) a unique virulence gene region, as well as a type IV secretion system (T4SS)-mediated high frequency mobilization system of plasmids. In this study, we analyzed surface structures of 57 strains of CA-MRSA/J, from various clinical sources including a death case, by scanning and transmission electron microscopy. The representative structures found were spikes (named spike X) of, for example, strain NN3 (adherent pathotype), spikes with a hexagonal cap (named spike X_C) of, for example, strain SI1 (fatal/invasive pathotype), long and filamentous aggregates (named FA) of strain NN55 (invasive pathotype), and long pilus-like structures (PLS) of, for example, strain TI5 (adherent pathotype). Spikes X and X_C resemble the structures of a bacteriophage in appearance and size, but FA shows no phage-like similarities. The role of spikes X and X_C, FA, or PLS in CA-MRSA/J pathogenesis is not known; however, the novel FA form strongly suggests unique CA-MRSA/J’s capacity to modify a phage-like structure. The genome sequences of those strains are currently under investigation.