Increased Sensitivity to Phagocytosis of Staphylococcus E‐46 after Growth in Artificial Media

Abstract

Staphylococcus E-46, which exhibits high virulence in mice mainly due to resistance to phagocytosis, gradually lost its virulence during growth in artificial media [Heart-Infusion (HI) slants]. Staphylococcus E-46 is coagulase-negative and DNase-positive, and has a capsule-like structure, and the less-virulent derivative (LVD) strain seemed not to be changed in this respect. The bacteria which had been exposed to HI slants for more than one year ( =LVD strain) became more sensitive to phagocytosis by mouse peritoneal macrophages than bacteria which were kept in a lyophilized state.The chemiluminescent response of macrophages to the LVD strain was remarkably higher than that to the original Staphylococcus E-46. When the LVD or the sera for opsonization were heated, the chemiluminescence to the LVD was as low as that to the original Staphylococcus E-46.Polyacrylamide gel electrophoresis of sonication-released membrane protein from the LVD strain showed a unique band with a molecular weight of about 40,000.The factor concerned with the virulence of Staphylococcus E-46 is discussed based on these results.

Increased resistance of bacteria after adherence to polymethyl methacrylate

“…K. Iwata (Department of Microbiology, Faculty of Medicine, University of Tokyo, Tokyo) from a biomaterial-centered infection, was used (Yamamoto and Iwata 1986). This strain is catalase-positive, coagulase-negative, nonhemolytic and encapsulated, and forms diffuse colonies on serum agar.…”

Bacterial adherence to bioinert and bioactive materials studied in vitro

“…A strain of Staphylococcus epidermidis (SE46), isolated by Yamamoto and Iwata (1986), was used. The bacteria were cultured for 48 h in 500 rnL of Trypticase soy broth (TSB) without dextrose (Difco Laboratories, Detroit, MI, U.S.A.), supplemented with 0.5 percent gluconic acid (Sigma Scientific, St. Louis, MO, U.S.A.).…”

In vitro analysis of the effects of biomaterial adherence on a Staphylococcus epidermidis strain's sensitivity to cephaloridine

“…6 The organism was grown in trypticase soy broth (TSB) without dextrose (Difco Laboratories) and supplemented with 0.5% gluconic acid (Sigma Scientific). Adherent populations were prepared by culturing SE-46 for 24 h in 500 mL of TSB, then decanting the culture media with the nonadherent organisms.…”

“…All studies utilized a catalase positive, coagulase negative, nonhemolytic, encapsulated strain of S. epidermidis (SE-46) that was isolated from a biomaterial-centered infection by K. Iwata. 6 The organism was grown in trypticase soy broth (TSB) without dextrose (Difco Laboratories) and supplemented with 0.5% gluconic acid (Sigma Scientific). Adherent populations were prepared by culturing SE-46 for 24 h in 500 mL of TSB, then decanting the culture media with the nonadherent organisms.…”