崔 龍洙

Significant advances have been made in recent years in our understanding of how methicillin resistance is acquired by Staphylococcus aureus. Integration of a staphylococcal cassette chromosome mec(SCCmec) element into the chromosome converts drug-sensitive S. aureus into the notorious hospital pathogen methicilin-resistant S. aureus(MRSA), which is resistant to practically all beta -lactam antibiotics. SCCmec is a novel class of mobile genetic element that is composed of the mec gene complex encoding methicillin resistance and the ccr gene complex that encodes recombinases responsible for its mobility. These elements also carry various resistance genes for non-beta -lactam antibiotics. After acquiring an SCCmec element, MRSA undergoes several mutational events and evolves into the most difficult-to-treat pathogen in hospitals, against which all extant antibiotics including vancomycin are ineffective. Recent epidemiological data imply that MRSA has embarked on another evolutionary path as a community pathogen, as at least one novel SCCmec element seems to have been successful in converting S. aureus strains from the normal human flora into MRSA.

コアグラーゼ陰性ブドウ球菌(CNS)のVancomycin(VCM)とTeicoplanin(TEIC)に対する感受性及び培地の影響について検討した.Staphylococcus epidermidisの1980年〜1981年分離菌に対するVCMとTEICのMIC値をNCCLSの基準で測定するとMueller-Hinton agar(MHA)とBrain Heart Infusion agar(BHIA)のどちらの培地を用いた場合でも,両薬剤に対して全て感性であった.また,1994年〜1997年分離菌のVCMに対する感性率はMHAで99.2%,BHIAで68.0%であった.同様に,TEICに対するMHAとBHIAでの感性率はそれぞれ97.5%,77.9%であり,年次的に感性率は低下していた