In vitro antimicrobial activity of carbapenem antibiotics against Pseudomonas aeruginosa, measured using a low-concentration Mueller-Hinton Agar culture medium

• Published in: Japanese journal of antibiotics Vol. 52; no. 6; p. 449
• Main Author: Igari, J
• Format: Journal Article
• Language: Japanese
• Published: Japan 01.06.1999
• Subjects: Agar; Carbapenems - pharmacology; Culture Media; Dose-Response Relationship, Drug; Drug Interactions; Drug Resistance, Microbial; Pseudomonas aeruginosa - drug effects; Thienamycins - pharmacology
• ISSN: 0368-2781

Ohya et al. noted that the antibacterial activity of carbapenem-family antibiotics against Pseudomonas aeruginosa was significantly enhanced through lowering the basic amino acid concentration in the culture medium. They reported that there was a marked difference in antimicrobial activity of panipenem (PAPM) against Pseudomonas aeruginosa between the culture medium with Mueller-Hinton Agar (MHA) diluted with distilled water and the non-diluted culture medium. We used 2,312 strains of fresh Pseudomonas aeruginosa, isolated from clinical materials, to examine the antibacterial activity of PAPM in non-diluted and diluted culture media. For testing the susceptibility, we employed the Showa disc method and agar plate dilution method. In the Showa disc method, the inhibition diameters of the tested microbial strains showed a larger distribution for both 16-fold and 40-fold diluted MHA, compared to the non-diluted MHA. The MIC values in the agar plate dilution method were also smaller in distribution for the 16-fold as well as the 40-fold diluted MHA, compared to the non-diluted culture media. Approximately 90% of the strains showed decreased MIC values, 2-8 times in the 16-fold diluted MHA and 2-16 times in the 40-fold diluted MHA. From the above results, we confirmed that the in vitro antibacterial activity of PAPM against Pseudomonas aeruginosa was enhanced through lowering the MHA concentration.