| Summary: | 碩士 === 國立高雄海洋科技大學 === 水產食品科學研究所 === 97 === V. parahaemolyticus is the most occurring foodborne pathogen in Taiwan and usually associated with seafoods. Thus, sanitary quality of white shrimp (Litopenaeus vannamei) sold at retail markets in Kaohsiung City and antibiotic resistance of Vibrio parahaemolyticus and Vibrio vulnificus isolated from those shrimps were studies. Thirty six samples of white shrimp were purchased from six traditional market places from June 2008 to April 2009. Total aerobic plates counts of shrimp samples ranged from 5.0 to 9.5 log CFU/g. The highest counts were obtained from samples collected in August (7.9 ± 1.3 log CFU/g). Colifom counts of samples ranged from <1.0 to 4.2 log CFU/g and only one sample was found to contain 3.0 log CFU/g of Escherichia coli. None of samples contained Salmonella spp. Seven samples (19%) was found to contain 3.6 to 23 MPN/g of Staphylococcus aureus. V. parahaemolyticus counts ranged from 0.6 to 8.0 log MPN/g, and the highest (6.9 ± 0.9 log MPN/g) and lowest counts (2.5 ± 1.7 log MPN/g) were obtained from samples collected from August and December, respectively. V. vunificus was isolated from 6 samples (17%). Pathogenic genes (tdh and trh genes) of V. parahaemolyticus was not found in all isolates obtained from medium enrichment. However, tdh gene was found in 5 samples (14%) based on multiplex PCR. All 6 V. vunificus isolates were found to possess vvh gene.
V. parahaemolyticus isolated from 31 samples (86.1%) showed resistance to ampicillin, followed by sulfamethoxazole (63.9%) and streptomycin (6.1%). All V. parahaemolyticus were not resistant to tetracycline, chloramphenicol, oxolinic acid. All V. vulnificus isolates (100%) were resistant to streptomycin, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were as high as 1024 μg/mL.
Thirty six oyster (Crassostrea gigas) samples collected from six market places and in the same time period of white shrimp were also analyzed to obtain sanitary quality and V. parahaemolyticus and V. vulnificus counts. Antibiotic resistance of V. parahaemolyticus and V. vulnificus isolated from those oyster were also studies. The level of volatile basic nitrogen (VBN), aerobic plate counts, coliform and E. coli, ranged from 1.22 to 10.91 mg/100g, 4.6 to 10.3 log CFU/g, <1 to 4.1 log CFU/g, <1 to 4.0 log CFU/g, respectively. None of samples contained Salmonella spp. Six samples (17%) was found to contain 3.6 MPN/g of S. aureus. V. parahaemolyticus counts ranged from 0.9 to 8.0 log MPN/g, and the highest (6.8 ± 1.3 log MPN/g) counts were obtained from samples collected in August. V. vunificus was isolated from 4 samples (11%). Pathogenic genes (tdh and trh genes) of V. parahaemolyticus were not found in all isolates obtained from medium enrichment. However, tdh gene was found in 5 samples (14%) based on multiplex PCR. All 6 V. vunificus isolates were found to possess vvh gene.
V. parahaemolyticus isolated from 26 samples (72.2%) showed resistance to ampicillin, followed by streptomycin (66.7%) and sulfamethoxazole (41.7%). All V. parahaemolyticus were not resistant to tetracycline, chloramphenicol, oxolinic acid. All V. vulnificus isolates (100%) were resistant to streptomycin, and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were as high as 1024 μg/mL.
According to the results of this study, the highest counts of total aerobic plate and V. parahaemolyticus were obtained in August. Pathogenic genes of V. parahaemolyticus was not found in the isolates obtained from medium enrichment. The most common antibiotic resistance of V. parahaemolyticus isolates was ampicillin. All V. vulnificus isolates were resistant to streptomycin. Results of this study could be useful for application of antibiotic in aquatic farming industry and father understanding of antibiotic resistance of Vibrio species.
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