Etiological analysis of 35 isolates of Vibrio parahaemolyticus causing food poisonings

Objective To study the serotypes,virulent genes and antibiotic resistance of Vibrio parahaemolyticus isolated from food poisonings in recent years,providing scientific basis for further prevention and control. Methods Serotypes of 35 isolates of Vibrio parahaemolyticus isolated by CDCs of Zhanjiang,Dongguan,Zhongshan,and Huizhou were determined with serological experiment. Virulent genes tdh and trh were detected by PCR. Antibiotic resistance was examined by K-B disk diffusion method. Results Thirty-five isolates of Vibrio parahaemolyticus causing food poisonings belonged to 6 serotypes of O1,O2,O3,O4,O8,and O10 and their constituent ratios were 20. 0%,2. 9%,62. 9%,8. 6%, 2. 9%,and 2. 9%,respectively. Of 35 isolates,18 isolates were identified as serotype O3: K6,accounting for 51. 4%( 18 /35). The carrying rates of tdh and trh genes were 88. 6%( 31 /35) and 8. 6%( 3 /35),respectively. All isolates were resistant to streptomycin,ampicillin and amikacin,and their resistance rates were 100%,80%( 28 /35) and 74. 3%( 26 /35),respectively. Their sensitivity rates ranged from 82. 9% to 94. 3% to tetracycline,ciprofloxacin,sulfamethoxazole,sulphonamides compound,chloramphenicol,and ceftriaxone. Conclusion The dominant serotype of Vibrio parahaemolyticus causing food poisonings in some cities of Guangdong Province was O3 and the most dominant serotype was O3: K6. Most of isolates had the tdh gene and were sensitive to many antibiotics.