Rinsho Biseibutsu Jinsoku Shindan Kenkyukai shi = JARMAM : Journal of the Association for Rapid Method and Automation in Microbiology最新文献

The centrifuge method with the use of Semi-Alkalin Proteinase (SAP) and NALC-NaOH, recommended by the "2007 edition of the assay guideline for detection of Mycobacterium tuberculosis," has significantly contributed to improving the sensitivities and specificities of both smear and culture tests for detection of acid fast bacilli (AFB). However, this method poses some challenges in terms of its cumbersome and time-consuming assay protocol. "TB-beads (Kyokuto Pharmaceutical Industrial Co., Ltd.)" is a newly-developed method for detection of AFB utilizing magnetic beads. We evaluated the quality of this method in comparison with the centrifuge method, focusing on the results of smear and culture tests. This evaluation study was conducted using both 5 positive and 5 negative sputum samples. The sensitivity of TB-beads for fluorescent smear tests, conducted using "Acri-stain," was almost the same as that of the centrifuge method. One advantage of TB-beads, however, was that it was very convenient to practice microscopic observation due to the clear background of the smeared glass slides. The comparison of the contamination rates between the two methods showed that TB-beads suggested significantly lower contamination rates. The centrifuge method resulted in 50% and 60% of contamination rates for HK Semisolid Isolation Medium and BacT/ALERT MP, respectively. On the other hand, the contamination rates of TB-beads for both of the culture methods were only 10%. With regard to the 5 positive sputum samples, the comparison of the detection rates between the centrifuge and TB-Beads method was made utilizing Myco Acid, Ogawa K, and BacT/ALERT MP. The TB-Beads method suggested higher detection rates for Myco Acid and Ogawa K, while there were no significant differences between the two methods for BacT/ALERT MP (16-23 days). TB-beads is an easy method that allows to simplify the process of smear tests, and contributes to significantly reducing the contamination rate of culture tests. It also contributes to improving the sensitivity and detection rate of AFB testing. Furthermore, it does not require centrifugation. Ultimately, TB-beads is an innovative, safe, and convenient testing method for detection of AFB, which enables laboratory technicians to save time for routine work.

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.

The Gram stain is an established method for bacterial identification, but the time needed to carry out this stain is 2-3 min. We attempted to shorten this time and stained a total of 70 clinical specimens isolated from using the Bartholomew & Mittwer (B&M) modified or Favor methods with a 3 s duration for washing and staining steps. Results were plotted and analyzed using a Hue Saturation Intensity (HSI) model. The range based on a plot of the two methods with the HSI model was presented as a reference interval. Our results indicated that 100% (35/35) of strains were Gram positive and 97.1% (34/35) were Gram negative for the quick B&M modified method. In the quick Favor method, 80.0% (28/35) were Gram positive and 68.6% (24/35) of strains were Gram negative. We propose that the quick B&M modified method is equivalent to the standard Gram staining method and is superior to the quick Favor method.

A diagnostic test for infection has been developed which uses the culture method but there still remains the issue of non-culturable pathogens. Although genetic testing has emerged as a solution to this problem, it is not yet widely used. There are various reasons for this which includes the gene amplification and analysis methods used as well as the users not being familiar with the selection criteria. In recent years, by using inexpensive instrumentation it has become possible to observe specimens using fluorescent staining and to easily identify the pathogens. Also equipment for gene and protein analysis has been developed that can analyze each level of gene transcription and translation in the expressed proteins. Today, due to the many developments in both analytical methods and instrumentation, major breakthroughs are being made in clinical microbiological testing. That is, first, to classify the infecting microorganism by fluorescent staining and then to identify the microorganism using DNA sequencing and mass spectrometry. In addition, the DNA sequencing and Melting curve analysis methods are used to test for antimicrobial resistance of infectious microorganisms. For non-culturable microbes and the growth response of microbes under stress conditions, the Phenotype-Microarray method is used. Therefore, once the weaknesses of each method are understood, it is possible to provide accurate and timely information to clinicians.

Some automated systems of the identification and susceptibility for microorganisms are used and prevail in hospital laboratories. One of the most serious problems is to perform accurate susceptibility testing for low-level resistant organisms, while antibiotic resistant microbes are increasing in medical fields. To evaluate automated machines for the susceptibility testing, several antibiotic resistant organisms were examined by plural technicians in some laboratories. Each strain of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycinintermediate S. aureus (VISA), extended-spectrum β-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae was tested by three automated systems of WalkAway, VITEK2/VITEK2 compact and Phoenix for susceptibility. The results for antibiotics generated by the systems were compared to those generated by reference methods according to CLSI guidelines. The results of WalkAway, VITEK2/VITEK2 compact, and Phoenix demonstrated 92%, 91%, and 96% of reproducibilities, 92%, 94%, and 91% of MIC agreements, 0.5%, 0.8%, and 0.3% of very major error (VME) and 0.3%, 1.4%, and 2.3% of major error (ME), respectively. All automated systems had a high reproducibility even under the performance of plural technicians, although the differences of VMEs and MEs were observed among the systems. From these data, the automated systems for antimicrobial susceptibility testing were more useful for the detection of antibiotic resistant organisms by understanding the characteristics of each system.

We have analyzed epidemiology of pandemic influenza (H1N1) 2009 in Aichi Medical University hospital. As a result, the characteristics of pandemic influenza (H1N1) 2009 was as follows. (1) The number of ordered rapid diagnostic test was 2.8 times compared with the seasonal influenza period. The number of ordered rapid diagnostic test of the seasonal influenza period had the peak in January to March. However, the peak in pandemic influenza (H1N1) 2009 was November. Also, the number of samples on the weekend had been more than that of the weekday. (2) Positive rate of each diagnostic kit did not have the difference between the seasonal influenza (31.3 ± 1.8%) and pandemic influenza (H1N1) 2009 (29.6%). (3) Age on most ordered samples were less than ten years old, and the number of samples in 11 to 20 years old was twice in comparison with the seasonal influenza. (4) Pandemic influenza (H1N1) 2009 in influenza A accounted for 96.9%. (5) Sensitivity and specificity of ESPLINE Influenza A&B-N (FUJIREBIO, Inc., Tokyo, Japan) to the pandemic influenza (H1N1) 2009 were 100% and 100%, respectively. Also, sensitivity and specificity of prorasuto Flu (Mitsubishi Chemical Medience Corporation, Tokyo, Japan) were 77.3%and 98.5%, respectively.