Studies On Enrichment Medium And Selective Differential Medium Of Pathogenic Vibrio

Pathogenic Vibrio belonging to genus Vibrio, which has 12 species, including Vibrio cholerae, Vibrio parahaemolyticus, Vibrio vulnificus, Vibrio damsela, Vibrio mimicus, Vibrio cincinnatiensis, Vibrio metschnikovii, Vibrio hollisae, Vibrio fluvialis, Vibrio furnissii, Vibrio alginolyticus and Vibrio carchariae. Pathogenic Vibrio is one of the important factors influencing Aquatic safety. As a type of halophilic bacteria, it usually exists in offing seawater, seabed sediment, plankton, and seafood (fish and seashell). Pathogenic Vibrio is the primary pathogen that causes food poisoning in littoral during summer and autumn. People could be infected mostly because of uncooked seafood or pickled food which are contaminated by Pathogenic Vibrio. The primary symptoms are bellyache, diarrhea, vomit, fever and so on. Life will be in danger if the patient couldn't be treated in time.Selective Differential media, which is based on biochemical reaction, is a detection technology. It has successfully combined the reaction of biochemistry and the traditional separation of biochemistry of bacterium, which is easy to observe the result of detection. In addition, there are some advantages-low cost, high sensitivity, specificity and rapidness. Selective Differential media is becoming the main trend of microbial detection. At present, only Vibrio parahaemolyticus, Vibrio cholerae and Vibrio vulnificus has a selective differential medium, but other pathogenic Vibrio not yet. The purpose of this study is to design Selective Differential Medium for the rapid separation, identification and detection of other Pathogenic Vibrio, to meet the needs of the increasingly stringent food safety standards and different test conditions.The researches carried out in this paper would be described as follows:1. Study on enrichment medium and culture conditions of Pathogenic VibrioThis research optimized Vibrio enrichment medium and culture conditions in order to obtain a method for enriching vibrio. The results showed as follow, taking Vibrio parahaemolyticus for example, the extract of the mycelia which had been cultured on Vibrio culture medium sealed by Double-Layer Kraft Paper in shake condition(36±1)℃,120 r/min is (1.8±0.6) times than that of the mycelia cultured on APW (GB/T4789.7-2008) under the same condition. The result of 12 Pathogenic Vibrio enrichment test showed that, Vibrio enrichment medium can effectively stimulate the growth and reproduction of 12 Pathogenic Vibrio. Vibrio enrichment medium is composed of tryptone 0.5%, fish Peptone 1.5%, yeast extract 0.2%, NaCl 3%, pH 8.6. Further experiment could be successfully carried on with the support of the above work.2. Study on Vibrio vulnificus Differential Medium Based on the specific enzyme systems and the corresponding metabolisms of Vibrio vulnificus, according to the resistibility to different antibacterial ingredients, VvDM was designed for the rapid separation, identification or detection of Vibrio vulnificus. The tests of color effects, plating efficiency, sensitivity and specificity were conducted to evaluate the efficiency of VvDM. The results showed that: VvDM had good selectivity and specificity for Vibrio vulnificus. After incubating for 16-24 h at 39℃, the Vibrio vulnificus formed yellow colonies on VvDM. The other strains did not form colonies or form green colonies. VvDM showed a mean plating efficiency of Vibrio vulnificus cells of (92.42±3.43)% and its detection limit was 101 cfu/mL. Accordingly, VvDM is useful to detect Vibrio vulnificus for kinds of inspection agencies with the strengthens of easily-operated, lower cost, convenience for observation and so on.3. Study on Vibrio mimicus Differential MediumBased on the specific enzyme systems and the corresponding metabolisms of Vibrio mimicus, according to the resistibility to different antibacterial ingredients, VmDM was designed for the rapid separation, identification or detection of Vibrio mimicus. The tests of color effects, plating efficiency, sensitivity and specificity were conducted to evaluate the efficiency of VmDM. The results showed that: VmDM has good selectivity and specificity for Vibrio mimicus. After incubating for 24 h at 37℃, the Vibrio mimicus formed green colonies on VmDM. The other strains did not form colonies or formed yellow colonies. VmDM showed a mean plating efficiency of Vibrio mimicus cells of (89.80±3.43)% and its detection limit was 102 cfu/mL. Accordingly, VmDM is useful for kinds of inspection agencies to detect Vibrio mimicus with the strengthens of easily-operated, lower cost, convenience for observation and so on.4. Study on Vibrio cincinnatiensis Differential MediumBased on the specific enzyme systems and the corresponding metabolisms of Vibrio cincinnatiensis, according to the resistibility to different antibacterial ingredients, VciDM was designed for the rapid separation, identification or detection of Vibrio cincinnatiensis. The tests of color effects, plating efficiency, sensitivity and specificity were done to evaluate the efficiency of VciDM. The results showed that:VciDM has good selectivity and specificity for Vibrio cincinnatiensis. After incubation for 16-24 h at 37℃, The Vibrio cincinnatiensis formed yellow colonies on VciDM. The other strains did not form colonies or formed green colonies.VciDM showed a mean plating efficiency of Vibrio cincinnatiensis cells of (82.14±4.45)% and its detection limit was 101cfu/mL. Accordingly, VciDM is useful for kinds of inspection agencies to detect Vibrio cincinnatiensis with the strengthens of being easily-operated, lower cost, convenience for observation and so on.5. Study on Vibrio damsela Differential MediumBased on the specific enzyme systems and the corresponding metabolisms of Vibrio damsela, according to the resistibility to different antibacterial ingredients, VdDM was designed for the rapid separation, identification or detection of Vibrio damsela. The tests of color effects, plating efficiency, sensitivity and specificity were done to evaluate the efficiency of VdDM. The results showed that:VdDM had good selectivity and specificity for Vibrio damsela. After incubation for 16-24 h at 37℃, the Vibrio damsela formed green colonies on VdDM. The other species of bacteria did not form colonies or formed yellow colonies. VdDM showed a mean plating efficiency of Vibrio damsela cells of (83.46±3.42)% and its detection limit was 101 cfu/mL. Accordingly, VdDM is suitable for kinds of inspection agencies to detect Vibrio damsela with the strengthens of being easily-operated, lower cost, convenience for observation and so on.Compared with the conventional methods (TCBS combined with the API 20E system or biochemistry assessor of Vibrionaceae), Vibrio enrichment medium is combined with four Selective Differential medias respectively, which can be used to isolate and detect Pathogenic Vibrio. Meanwhile, it can be identified with several advantages:easily-operated, economical, convenient for observation, high sensitivity and specificity.