• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.164-170
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• 2019

The absorption and release capacities, survival efficiency, and recovery rates of five kinds of transport media were evaluated based on the swab elution method (Quantitative) of CLSI (Clinical and Laboratory Standards Institute) M40-A2. Liquid media showed mostly better results than semi-solid media in the three evaluations. The flocked swabs had better ability to absorption and discharge bacteria than the standard swabs. The liquid medium (S4) had the best survival efficiency. Pneumococcal strains with poor growth had a higher survival efficiency and recovery rate in liquid media (S4, S5). The results of microbial recovery showed that S. pyogenes met all the CLSI standards in all media. S. pneumoniae was inadequate in the semi- solid media (S2, S3) and all the remaining media met the criteria. H. influenzae was unsuitable in semi-solid media (S1, S3) and met the criteria in semi-solid medium (S2) and liquid medium (S4, S5). The viability of the H. influenzae, pneumococcal strain causing respiratory disease, was poor in most media. Overgrowth of P. aeruginosa was observed at room temperature. The combination of liquid medium and flocked swab confirmed the best results in the three evaluation methods.

• Biomedical Science Letters
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• v.29 no.4
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• pp.249-255
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• 2023

Transporting clinical samples for microbiological testing requires a proper transport medium that guarantees the survival of microorganisms. Therefore, the aim of the study was to determine the ability of Amies Transport Medium (ATM) to maintain the viability of microorganisms in clinical specimens and its suitability as a transport medium for microbiological testing. This study evaluated the performance of swab provided by KS Co., Ltd. for three groups of bacteria comprising aerobic and facultative anaerobic bacteria, anaerobic bacteria, and fastidious bacteria, according to the Clinical and Laboratory Standard Institute (CLSI) 8.11.2. The ATM stability test was conducted by dividing the medium into two groups based on the product expiration date of use. All tested media, A and B (the date of manufacture and expiration date are different) showed ≥5 CFU, and there was no significant difference in the result values of Category A and Category B with different serial numbers for each test. The results of this experiment when cross-checked with the guidelines suggest that ATM is a suitable transport medium for microbiological testing, as it maintains the viability of microorganisms and is suitable for overgrowth trials. In addition, compared to the number of CFUs at the origin, the number of CFUs did not increase by more than 1 log after storage. These results have important implications for the development of transport media that can guarantee the survival of microorganisms in clinical specimens.

• Pediatric Infection and Vaccine
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• v.18 no.2
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• pp.109-116
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• 2011

Purpose : Pneumococcus is one of the most important causes of invasive infection through the childhood period. In January 2008, the Clinical and Laboratory Standards Institute (CLSI) published revised penicillin breakpoints for Streptococcus pneumoniae and penicillin susceptibility rates of S. pneumoniae increased in Korea. This study was performed to determine the probability of oral amoxicillin for the empirical treatment achieving bactericidal exposure against pneumococcus using pharmacodynamics model. Methods : Twenty-three isolates of pneumococci were subjected to determine minimum inhibitory concentration (MIC) for ${\beta}$-lactams and macrolide. For the ${\beta}$-lactams, exposure of fT >MIC (time that free drug concentrations remain above the MIC) for 50% of the administration interval have determined the probability of target attainment (PTA), and regimens that had a PTA >90% were considered optimal. An analysis was performed by applying MIC of 23 isolates to a 5000-patient Monte Carlo simulation model. Results : Among 23 isolates from healthy children, 7 (30.4%) isolates were MIC ${\leq}$1.0 ${\mu}g$/mL and 19 (82.6%) were MIC ${\leq}$2 ${\mu}g$/mL for amoxicillin. Amoxicillin 40 mg/kg/day achieved PTA >90% at MIC ${\leq}$1.0 ${\mu}g$/mL but PTA decreased to 52% at MIC 2 ${\mu}g$/mL, whereas amoxicillin 90 mg/kg/day can predict 97% of PTA at MIC 2 ${\mu}g$/mL. Overall, oral amoxicillin 90 mg/ kg/day for the empirical treatment against pneumococcus can expect more successful response in Korean children. Conclusion : Considering the resistantce pattern of pneumococci in Korean children, we estimate that oral amoxicillin 90 mg/kg/day will provide a pharmacodynamic advantage for the empirical treatment against pneumococcus. And low dose amoxicillin or macrolide are expected to have higher chance of treatment failure than high dose oral amoxicillin.

• Biomedical Science Letters
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• v.22 no.4
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• pp.174-183
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• 2016

In the present study, a serum-based minimum inhibitory concentration (MIC) testing to caspofungin was optimized and evaluated to solve the limitations of the conventional Clinical and Laboratory Standards Institute (CLSI) guideline-based antifungal agent MIC test and the usefulness of this testing for clinical application was determined. A total of 105 Candida albicans clinical isolates were used for measuring MIC to caspofungin. Results showed that growth characteristics were different according to types of serum and the mouse serum was the most suitable for this assay. In order to measure the optimal concentration of mouse serum, 0 to 100% mouse serum were added to the media during fungal culture. The optimal concentration of serum was 50% when consideration of antifungal agent administration and inoculum size, serum components and ease of hyphae separated, and the consideration of the degree of growth. In comparison of the usefulness between the conventional Alamar-modified broth microdilution MIC assay and 50% mouse serum-based MIC testing, the range of $MIC_{80}$ of the Alamar-modified broth microdilution MIC assay was $0.13{\sim}2.0{\mu}g/mL$ (SD ${\pm}0.42{\mu}g/mL$) and that of the 50% mouse serum-based MIC assay was $2.0{\sim}32.0{\mu}g/mL$ (SD ${\pm}9.01{\mu}g/mL$). The range of $MIC_{50}$ of the Alamar-modified broth microdilution MIC assay was $0.13{\sim}2.0{\mu}g/mL$ (SD ${\pm}0.40{\mu}g/mL$) and that of the 50% mouse serum-based MIC assay was $1.0{\sim}16.0{\mu}g/mL$ (SD ${\pm}2.36{\mu}g/mL$). The MICs of 50% mouse serum-based MIC testing was increased by up to 4 to 64 times than Alamar-modified broth microdilution MIC assay. In conclusion, a 50% mouse serum-based MIC assay was more useful for measuring MIC in Candida albicans clinical isolates than conventional colorimetric broth microdilution MIC testing.