[Direct identification method for bacteria in positive blood culture bottles using MALDI biotyper].

We investigated the relevance of direct identification method for bacteria from blood culture bottles using MALDI Biotyper(Bruker Co.). One hundred fourteen bacterial strains obtained from blood culture bottles were analyzed using the pretreatment method recommended by Bruker Corporation. The identification rate with recommended pretreatment was 76.3% (87/114). Twenty seven samples that were not identified with the pretreatment method were further analyzed using our modified method. Of these, twelve were identified, improving the identification rate to 86.8% (99/114). These results suggest that our modified pretreatment combined with pretreatment method recommended by Bruker Corporation yields improved identification of bacteria from blood culture bottles using MALDI Biotyper system.

[Influences of %T>MIC achievement probability due to the difference of the MIC measurement concentration range-analysis of meropenem for Pseudomonas aeruginosa-].

We attempted to analyze any influences to %T>MIC achievement probability due to the difference of the MIC measurement concentration range of MEPM for 613 strains of Pseudomonas aeruginosa by the Monte Carlo simulation method. As for the analysis, we calculated the achievement probability of 30% and 50% for MEPM %T>MIC by the administration volume of MEPM: 250 mg, 500 mg, and 1,000 mg, the administration time: 0.5 h, and 3 h, the administration frequency: 2 times, and 3 times, and the renal excretion capability: Normal, Slight, Moderate, and High abnormal with the 3 types of MIC concentration measurement level 1) <=0.06~>=256 µg/ml: 13 levels, 2) <=0.5~>=32 µg/ml: 7 levels, and 3) <=1~>=16 µg/ml: 5 levels. As the result, we found the following findings; 1. In terms of the administration of normal renal excretion capability, 250 mg, in comparison with 500 mg and 1,000 mg, indicated the differential due to the difference of MIC measurement concentration range. 2. The administration volume of MEPM 500 mg which has been recommended shown the less differential of the achievement probability due to the difference of MIC measurement concentration range. As the renal excretion was shifted through Normal to Slight to Moderate to High abnormal, the differential of the achievement probability due to the difference of MIC measurement concentration range was gradually decreased. With these results, PK/PD analysis is possible for the 5 levels measurement concentration. It is significant that the facility using the automated microbiology analyzer can provide not only the MIC report, but also the information on the appropriate administration method for antibacterial drug by PK/PD analysis.