Quality Assurance for Commercially Prepared Microbiological Culture Media

Choi, Tae Yeal

Abstract

BACKGROUND: Culture media that perform as intended are crucial to accurate work by a clinical microbiology laboratory. The author evaluated commercially prepared microbiological culture media for quality assurance. MATERIAL AND METHODS: Five types of commercially prepared media from Shin Yang Chemical Co., Ltd. were evaluated in Hanyang University Hospital for one year. Five types included blood agar media, chocolate agar, MacConkey agar, Salmonella-Shigella agar and Mueller-Hinton agar. All media were evaluated by NCCLS M22-A2 (Quality assurance for commercially prepared microbiological culture media-second edition; approved standard, 1996).
RESULTS
Blood agar media provided luxuriant growth of many bacteria-especially the fastidious streptococci and pneumococci, as shown by early colonial development and clear hemolytic reactions with S. pyogeses. Chocolate agar supported growth of fastidious bacteria such as N. gonorrheae and H. influenzae. MacConkey agar gave excellent differentiation between coliforms and non-lactose fermenters with inhibition of Gram-positive micrococci. Salmonella-Shigella agar was a good differential selective medium for the isolation of Salmonella and some Shigella species from clinical specimens. Mueller-Hinton agar showed good reproducibility for antimicrobial susceptibility test by the disk diffusion method.
CONCLUSION
The five types of commercially prepared culture media have demonstrated competence and integrity for bacterial culture in clinical trial. Theses media could be used without performance quality assurance test by user.