Final report from the Committee on Antimicrobial Susceptibility Testing, Japanese Society of Chemotherapy, on the agar dilution method (2007)

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).

Antibacterial and antifungal activities of isoprenoids

“…Antibacterial assays were performed in accordance with the agar plate dilution method recommended by the Japanese Society of Chemotherapy [23][24][25].…”

“…The Minimal Inhibitory Concentration (MIC) at which a molecule exerted antimicrobial activity was defined as less than 800 µg/mL in accordance with the criterion set forth by the Japanese Society of Chemotherapy [23][24][25]. Media were sterilized using an STH 364 FA autoclave (Advantec Toyo Kaisha, Ltd.).…”

Naphthacemycins, novel circumventors of β-lactam resistance in MRSA, produced by Streptomyces sp. KB-3346-5. I. The taxonomy of the producing strain, and the fermentation, isolation and antibacterial activities

“…16 Though its skeleton is 8-oxobenzo [a] naphthacene, it has a 1,3-dihydroxy-10,10-dimethylanthrone unit, similar to the naphthacemycins. Its desulfonated analog, benastatin A (25), is active against Gram-positive bacteria. 17 Bischloroanthrabenzoxocinone (26), produced by Streptomyces sp., also has the same unit.…”

“…4 A larger panel for sensitivity testing of clinically isolated MRSA (22 strains) and drug susceptible (MSSA) organisms (5 strains) were carried out by the agar dilution method 25 in the presence of imipenem and/or naphthacemycins. An overnight culture of MRSA and MSSA strains was diluted with fresh medium to the appropriate bacterial density and spread onto a plate of Difco Mueller Hinton Agar (Becton, Dickinson and Company, Sparks, MD, USA) containing serial twofold dilutions of imipenem or naphthacemycins.…”

Antibiotic Resistance Profiling and Genotyping of Vancomycin-Resistant Enterococci Collected from an Urban River Basin in the Provincial City of Miyazaki, Japan

“…The MIC against each antibiotic was determined on Mueller Hinton agar using the agar dilution method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines [23]. The enterococcal isolates were cultured for 24 h in Mueller Hinton broth (Becton Dickinson, Spark, MD, USA) and then diluted to a final concentration of approximately 1 × 10 5 CFU·mL −1 with fresh Mueller Hinton broth.…”