TABLE 3.

Susceptibilities of various staphylococci to S. pneumoniae strain Pn-20 bactericidal effect and to external H2O2 and their catalase activities

Staphylococcus strainSusceptibility to S. pneumoniae killing IK6 (log10 CFU ± SD)aH2O2 susceptibility (Δlog10 CFU)bCatalase activity (mU per 108 CFU)
S. aureus (Newman)6.4 ± 0.3−2.5161
S. aureus (Newman) in medium supplemented with catalase0*+1.5ND
S. aureus (Newman) under anaerobic conditions0*NDcND
S. aureus (ALR)5.35 ± 0.93−1.5ND
S. epidermidis<2+0.3524
S. xylosus<2+0.21,050
S. sciurii<2+0.47,334
  • a IK6 = maximal staphylococcal inoculum killed by 106 CFU of S. pneumoniae (Pn-20) at 6 h. *, detection level = 50 CFU/well. IK values are averages from at least three independent experiments ± SD.

  • b Net reduction in log10 CFU at 6 h compared to the initial 7.7 log10 CFU of S. aureus in medium supplemented with H2O2 periodically.

  • c ND, not done.