碩士 / 國立嘉義大學 / 獸醫學系研究所 / 106 / Streptococcosis is an important bacterial disease in cultured Taiwan tilapia (Oreochromis sp.) and caused serious economic losses. In this study, 67 strains of Streptococcus were isolated from cultured Taiwan Tilapia in Chiayi county within year 2016, and tested the characteristic by API 20 Strep system, 16S rDNA sequence analysis, multiplex polymerase chain reaction in order to comparison and identification of strains. In addition, minimum inhibitory concentration (MIC) of 7 kinds antibiotics (amoxicillin, ampicillin, doxycycline, erythromycin, florfenicol, lincomycin and oxytetracycline) were used to 67 strains. According to the identify result of 67 Streptococcus-like isolates, 1 strain is Lactococcus garvieae, 57 for Streptococcus agalactiae, and 9 for Streptococcus iniae. According to 16S rDNA sequence analysis, the similarity of L. garvieae, S. agalactiae and S. iniae were 99.4 %, 97.3-100 % and 98.4-100 % separately. Antimicrobial susceptibilities of 67 isolates were determined by micro broth dilution method. It showed well effective of amoxicillin, ampicillin, doxycycline, erythromycin, lincomycin and oxytetracycline to L. garvieae, the MIC90 results between 0.25-0.125 g/mL. Same results occur in amoxicillin, doxycycline, erythromycin, lincomycin and oxytetracycline to S. agalactiae. In addition, MIC90 results are 0.125 g/mL in amoxicillin, doxycycline, erythromycin, lincomycin and oxytetracycline to S. iniae. All isolates shows no resistance to 7 kinds antibiotics. In conclusion, S. agalactiae is the main pathogen of Streptococcosis in Taiwan tilapia (Oreochromis sp.). Therefore, antibacterial is still an effective way to control Streptococcosis of Taiwan tilapia.
| Identifer | oai:union.ndltd.org:TW/106NCYU5541004 |
| Date | January 2018 |
| Creators | Tu, Hsien-Yi, 杜弦逸 |
| Contributors | Wang, Jiann-Hsiung, 王建雄 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 86 |
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