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Updated: May 27, 2026

Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus (MRSA)
Published on: February 9, 2011
[Influence of inoculum size on MICs for methicillin-susceptible Staphylococcus aureus and methicillin-resistant
Noriko Miyake1, Masako Kadowaki, Yoriko Sato
1Faculty of Medicine and Biosystemic Science, Graduate School of Medical Science, Kyushu University.
Abstract:
Using 49 clinical methicillin-susceptible Staphylococcus aureus isolates (MSSA) and 54 clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates, we examined the change of MIC using five different inocula (2.5-4 x 10(2) cfu/spot-2.5-4 x 10(6) cfu/spot). We found the big change of the MIC with the increase of the inoculum size in ampicillin against MSSA, and the change was small in cefazolin, meropenem, ciprofloxacin. For anti-MRSA antibiotics, we found the small change with the increase of the inoculums size in vancomycin and arbekacin, and the middle change in teicoplanin and linezolid against MSSA and MRSA. The data from this study suggest that in serious and high inocula infections caused by S. aureus, the presence of an inoculum effect should be considered in curing.
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