IMPROVED MEDIUM FOR DETECTION OF KLEBSIELLA IN POWDERED MILK |
| |
Authors: | HONG GAO QI-LI GAO XIA ZHANG CHUN GUAN MAO-HUANG LUO HAI-BIN ZHANG PEI LIU HAI-YING ZHANG JING LI |
| |
Affiliation: | Tianjin Key Lab of Cyto-genetical and Molecular Regulation Chemistry and Life Science College Tianjin Normal University Tianjin 300387, China; Tianjin Entry-Exit Inspection and Quarantine Bureau No. 8, ZhaoFa XinCun, 2nd Avenue Tianjin Economic-Technological Development Area Tianjin 300456, China |
| |
Abstract: | The selectivities to pathogenic Klebsiella strains of different isolation media were compared by known standard strains. The modified MacConkey-inositol-carbenicillin (MCIC) medium (Named MCIAC, MacConkey-inositol-adonitol-carbenicillin) supplemented with adonitol gave no false-negative colonies, and exhibited higher selectivity. MCIC and Simmons citrate agar with inositol (SCAI) media gave two false-negative colonies, respectively. These three media all gave two false-positive colonies, respectively. Salmonella Shigella medium gave four false-negative colonies and five false-positive colonies. Violet red bile glucose agar medium gave the most false-positive colonies, although it gave no false-negative colonies. One hundred samples of powdered milk were examined by MCIAC, MCIC and SCAI plates. The typical positive colonies were further identified using Vitek GNI Auto Microbic system and API 20E system. The results showed that the specificity of the MCIAC medium was higher than MCIC and SCAI media. PRACTICAL APPLICATIONS MacConkey-inositol-carbenicillin (MCIC) is the most commonly used selective medium for the detection of Klebsiella . But some inositol-nonfermenting Klebsiella strains would be missed when selected by this medium. We improved the MCIC medium by supplementing with 1% adonitol. The new modified medium (MacConkey-inositol-adonitol-carbenicillin, MCIAC) had advantages over other selective Klebsiella media in having a higher selectivity and an incubation time of only 16–24 h. MCIAC could be routinely used for pathogenic Klebsiella selection of powdered milk and other food samples. |
| |
Keywords: | |
|
|