Methicillin-resistant coagulase-negative staphylococci Methicillin-resistant. spa Staphylococcus aureus

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1 Methicillin-resistant coagulase-negative staphylococci Methicillin-resistant Staphylococcus aureus 1) 1) 1) 1) 1) 2) 3) 4) 2) 1) MBC 2) 3) 4) Methicillin-resistant Staphylococcus aureus (MRSA) Staphylococcus aureus Methicillinresistant Staphylococcus capitis (MR-S. capitis) Clinical and Laboratory Standards Institute (CLSI) spa Staphylococcus aureus meca MRSA MRSA Key words: MRSA, CNS, Methicillin-resistant Staphylococcus aureus (MR- SA) , 2) 1940 G 2) MRSA ( ) 3201 MBC TEL: FAX: masaeyamtokyo-med.ac.jp 3, 4) (Microscan WalkAway40, DADE BEHRING) Methicillin-resistant Staphylococcus capitis (MR-S. capitis) MRSA 3 MRSA Pulsed-field gel electrophoresis (PFGE) 5, 6) MRSA 20 Vol. 15 No

2 MRSA 127 I. 1. MRSA MRSA 1 BA, BD (BD) 35 5 BA S. aureus MR-S. capitis S. aureus MRSA MRSA A 3. MRSA 7 5 (1) DNase DNA MRSA (BD) (2) MicroScan Pos Combo41J (PC41J) (DADE BEHRING) 2 41J 1 WalkAway MicroScan auto- SCAN4 (DADE BHRING) (3) MuellerHinton (BD) CLSI (BD) oxacillin (MPIPC), ampicillin (ABPC), cefotiam (CTM), imipenem (IPM), erythromycin (EM), clindamycin (CLDM), fosfomycin (FOM), levofloxacin (LVFX), gentamicin (GM), arbekacin (ABK), minocycline (MINO), vancomycin (VCM) 12 CLSI 4. PCR meca spa MRSA PCR meca spa DNA mecaspa meca spa mecaspa 5. TSST-1 1 MRSA 2 A BA CO 2 S. aureus CNS S. aureus CO 2 MRSA Vol. 15 No

3 128 2 A 82M No /12/1 S CTM, IPM/CS VCM, MEPM SBTPC Geckler3 GPC2 B 75M No /12/24, PIPC, MEPM, CLDM, TEIC Geckler3 GPC3 C 75M No. 3 No /1/ /1/30 CLDM, PIPC, CFPM, CPFX, VCM GPC3 WBC1 Geckler5 GPC1 D 72F No /1/30 No /1/30 MEPM, CLDM CPFX, PIPC, VCM, CEZ, CTM GPC WBC2 GPC WBC2 E 87M No /2/6 CTM, PIPC, CEZ, VCM, TEIC GPC WBC CTM: cefotiam, IPM/CS: imipenem/cilastatin sodium, VCM: vancomycin, MEPM: meropenem, SBTPC: sultamicillin, PIPC: piperacillin, CLDM: clindamycin TEIC: teicoplanin CFPM: cefepime, CPFX: ciprofloxacin, CEZ: cefazolin, GPC: Gram-positive cocci SET-RPLA TSST-1 TST-RPLA 6. (PFGE) MRSA 7 MRSA Tenover 7) PFGE 8, 9) smai 7. 7 MRSA 5 10) 24 BA McF ml BA BA 96 II. 1. (1) MRSA 7 3 No. 5 DNA MRSA 3 DNase MRSA 7 DNase MRSA (2) MicroScan Pos Combo41J (WalkAway 40) Vol. 15 No

4 MRSA MR-S. capitis 24 7 MRSA VogesProskauer No. 2 (3) PC41J IPM, EM, FOM GM, ABK, MINO, VCM 7 S R 2. PCR meca spa 7 meca spa 4 3. C No. 5 6 II TSST-1 No PFGE MRSA PFGE 2 No. 1, No. 2, No. 3, No. 4, No. 7 No. 5, No. 6 3 MRSA DNA Dnase MRSA No. 1 NG NG NG No. 2 NG NG NG No. 3 NG NG NG No. 4 NG NG NG No. 5 NG NG NG No. 6 NG NG NG No. 7 NG NG NG NG: no growth 1 Vol. 15 No

5 130 4 Tenover PFGE No. 5, No. 1 3 No. 1 2mm b 1mmb 7 2 PFGE SmaI 17: No. 17 Y: Yeast chromosomes, Saccharomyces cerevisiae C: mm III. MRSA A, B, C MRSA S. capitis C, No. 3 2 MRSA 3524 MIC MRSA 5 4 meca spa TSST-1 PFGE No. 1 II C A No. 2 II C A No. 3 II C A No. 4 II C A No. 5 C A No. 6 II C A No. 7 II C A 24 Vol. 15 No

6 MRSA Vol. 15 No

7 132 PFGE 5)7) MRSA 1) MRSA Acar small colony variant (SCV) 3) ST 4) MRSA 7 6 II MRSA 11, 12) MRSA MRSA MRSA 1) CHE- MOTHERAPY 37: ) (MRSA) 55(5): ) Acar, J. F., F. W. Goldstein., P. Lagrange Humaninfections caused by thiamine- or menadion requiring Staphyloccus aureus. J. Clin. Microbiol. 8: ) MuellerHinton MRSA 12: ) MRSA 12: 913 6) p ) Tenover, F. C., R. D. Arbeit R. V. Goering, et al Interpreting chromosomal DNA restriction patterns produced by pulsed-field gel electrophoresis: criteria for bacterial strain typing. J. Clin. Microbiol. 33: ) Bannerman, T. L., G. A. Hancock, F. C. Tenover, et al Pulsed-field gel electrophoresis as a replacement for bacteriophage typing of Staphylococcus aureus. J. Clin. Microbiol. 33: ) : ) : ) (1) p ) IV p , 2 26 Vol. 15 No

8 MRSA 133 Methicillin-resistant Staphylococcus aureus Was Incorrectly Identified as Methicillin-resistant coagulase-negative staphylococci Due to Retarded Growth during Aerobic Incubation. Masae Yamamoto, 1) Daisuke Kawahata, 1) Miyuki Tsukahara, 1) Naomi Umebayashi, 1) Sadaaki Nagano, 1) Ichiro Takahashi, 2) Mieko Goto, 3) Katsuko Okuzumi, 4) Tsuyoshi Oishi 2) 1) Mitsubishi-Kagaku BCL in Tokyo Medical University Kasumigaura Hospital 2) Department of Infectious Disease, Tokyo Medical University Kasumigaura Hospital 3) Division of Infectious Diseases, Advanced Clinical Center, Institute of Medical Science 4) Dokkyo University School of Medicine, Hospital Department of Medical Safety Administration Division of Infection Control We isolated 7 strains of Methicillin-resistant Staphylococcus aureus (MRSA) characterized with retarded growth by aerobic culture from 5 patients. During the incubation for the primary separation, all of the isolated strains formed typical colonies suggestive of Staphylococcus aureus on sheep blood agar medium by incubation under 5 CO 2 gas at 35 overnight. However, the test results obtained by automatic instruments for 24 hours failed to demonstrate any growth and 42 hours later, the instruments recognized the tested organism as Methicillin-resistant Staphylococcus capitis (MR-S. capitis). Accordingly, given that di#erent incubation conditions might be responsible for such an inconsistency, we compared the results obtained under aerobic culture with those under 5 CO 2 gas. Formation of colonies of this bacterium required 96 hours under aerobic incubation and 24 hours under CO 2 gas incubation, indicating di#erent growth rates. Di#erences in growth rates of this bacterium under incubation conditions were associated with incorrect judgment even in both the identification test to be performed under aerobic culture and the drug sensitivity test according to Clinical and Laboratory Standards Institute (CLSI) method. As for the currently isolated 7 strains, biochemical characteristics including Gram-positive-cocci, catalase positive features, 7.5 salt resistance and mannitol degrading ability, as well as possession of spa gene were confirmed, whereby they were identified as Staphylococcus aureus. Furthermore, possession of meca gene permitted us to verify MRSA genetically. In light of existence of the special strains like the present MRSA requiring CO 2 gas incubation, we hope that this would be regarded as an important pitfall upon aerobic incubation in future. Vol. 15 No