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Abstract  In 1968, the agar dilution method was developed as an independent Japanese method for measuring the minimal inhibitory concentration (MIC) of antimicrobial agents. As this method differed in a few respects from the MIC measurement methods used in other countries, it was revised in 1981, by a committee headed by Susumu Mitsuhashi, and the revised method (Chemotherapy 29:76–79, 1981) has been used since then. In 1979, an agar dilution method for measuring the MIC of anaerobes was developed by a committee chaired by Nozomu Kosakai (Chemotherapy 27:559–561, 1979). In 1990, a committee headed by Sachiko Goto approved a broth microdilution method for nonfastidious bacteria (Chemotherapy 38:102–105, 1990). Later, a committee headed by Atsushi Saito examined media that would be suitable for nonfastidious bacteria and fastidious bacteria, and they endeavored to prepare a broth microdilution method for anaerobic bacteria. In this context, a new broth microdilution method was proposed at the 40th Annual Meeting of the Japanese Society of Chemotherapy (JSC) in Nagoya in 1992, and the proposal was adopted as the standard JSC method after some modification (Chemotherapy 41: 183–189, 1993). The agar dilution method has remained unrevised for approximately 20 years. A proposal to review this method was recently made, and the 2007 Committee on Antimicrobial Susceptibility Testing was formed, comprising the JSC members listed below. Under the auspices of this committee, the method revised in 1981 was reviewed in comparison to the international standard method (Clinical and Laboratory Standards Institute [CLSI] method). [ABSTRACT FROM AUTHOR]

Abstract  Some methicillin-resistant Staphylococcus aureus (MRSA) strains in which combinations of vancomycin (VCM) and β-lactam antibiotics show antagonism have recently emerged, and these strains are called β-lactaminduced VCM-resistant MRSA (BIVR). We examined whether various antibiotics exhibited an antagonistic effect with VCM when used against Mu3 and Fu10 (representative BIVR strains), using a simple agar disc method. Chloramphenicol, tetracyclines, macrolides, and lincosamides showed an antagonistic effect with VCM. We attempted to elucidate the antagonistic mechanism of a combination of VCM and minocycline (MINO) in BIVR strains. We determined the rates of autolysis, autolytic activities, and the change in morphology of Mu3 treated with a combination of VCM and MINO. We observed that Mu3 grown in a combination of VCM and MINO showed increasing rates of autolysis, and lower minimal bacteriolytic enzyme dose (MBD) values compared with Mu3 grown in VCM alone, but no cell wall thickening was observed. Taken together, these results suggest that cell wall thickening may not be essential in the increased resistance of BIVR strains. Our present data therefore suggest that these combination therapies of VCM with tetracyclines should be adopted with great care in order to prevent VCM treatment failure. [ABSTRACT FROM AUTHOR]

Recently we have heard warnings of an outbreak of a highly pathogenic avian influenza virus (H5N1). Although, to prevent such infections we must prepare anti-viral drugs and type-specific vaccines against influenza, we need various simple and effective protection methods, such as the use of face masks for public health. Also, in any consideration of bacterial infections, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococci (VRE), and multidrug-resistant Pseudomonas aeruginosa (MDRP) also pose serious concerns which must be addressed. I examined the antiviral activity of gentian violet (GV) and GV-dyed cloth against the influenza A (H1N1) virus. Time-kill studies were carried out, and the virus titer was determined based on the 50% tissue culture infective dose (TCID50). The minimum inhibitory concentrations (MICs) of GV against bacteria were also determined, and the killing activities of the GV-dyed cloth were judged from viable cell counts. GV immediately killed the influenza A virus and this was confirmed by electron microscopy. Moreover, cloth dyed with a combination of GV and copper showed not only excellent antiviral activity but also prominent bactericidal activities. [ABSTRACT FROM AUTHOR]

Minimum inhibitory concentrations (MICs) of vancomycin (VCM) and teicoplanin (TEIC) were measured using a novel susceptibility test based on the chemiluminescence assay (CA) method (Rapid-Lumi Eiken; Eiken Chemicals, Tokyo, Japan) against 33 strains in total: 7, 5, and 10 strains of which are VCM-resistant enterococci (VRE) with vanA, vanB, and vanC genes, respectively, and the other 11 strains are vancomycin-susceptible enterococci (VSE). The results were in good accordance with the values determined by the standard broth dilution method approved by the National Committee for Clinical Laboratory Standards (NCCLS): i.e., 88% (29/33) of consistency for VCM and 97% (32/33) for TEIC, respectively. In addition, genotypes in VRE strains (vanA, vanB, vanC-1, and vanC-2/3 genes) were properly estimated from the results of the CA method and the NCCLS interpretive categories, even though the incubation time was very short (2–4?h). In conclusion, it was found that the new method is reliable and rapid to detect VRE strains in clinical laboratories. [ABSTRACT FROM AUTHOR]

Abstract We could not detect hetero-vancomycin-intermediate resistant Staphylococcus aureus (hetero-VISA), according to the definition of hetero-VISA, from the clinical isolates of 140 methicillin-resistant S. aureus (MRSA) strains. However, 15 ß-lactam antibiotic-induced vancomycin-resistant MRSA (BIVR) strains were detected from the same strains. We screened 1882 MRSA clinical isolates obtained in 2002 from 21 institutes throughout Japan. The detection rate of blood-isolated BIVR was 12.6% (19/151), and that of nonblood-isolated BIVR was 4.9% (85/1731; P < 0.001; ?2 test). Uridine-diphosphate-N-acetylmuramyl-L-alanyl-D-isoglutamyl-L-lysine, used as the peptidoglycan material of S. aureus, showed the same results as ß-lactam antibiotics in BIVR. [ABSTRACT FROM AUTHOR]