九龙江下游河口水域抗生素及抗性细菌的分布

2011年8月和2012年5月对九龙江下游河口流域中的四环素和氟甲砜霉素的残留进行检测,显示这2种抗生素含量呈现明显的季节性,四环素(8月)和氟甲砜霉素(5月)的平均浓度分别为2.81ng/L和16.28ng/L.同时采用抗生素平板筛选培养法分析得出分析抗性细菌的丰度,得出2011年8月和2012年5月该海域中表层水样中四环素抗性细菌平+均丰度分别为1.14×105和8.41×103cells/mL,氟甲砜霉素抗性细菌的平均丰度分别为1.61×102cells/mL和5.88×102cells/mL.四环素抗性细菌的丰度明显高于氟甲砜霉素抗性细菌.2种抗生素抗性细菌的季节差异与抗生素含量的季节差异一致.2种抗生素抗性细菌的丰度与抗生素浓度均不具有显著相关性,显示九龙江流域水体中抗生素浓度不是决定抗性细菌的丰度的唯一因素.

Distribution of antibiotics residue and resistant bacteria in the downstream and estuarine area in Jiulong River.

Concentration of tetracycline and flofenicol were analyzed in the surface water of downstream and estuarine area in Jiulong River, Southeast of China. Tetracycline was detected in all the water samples in August 2011 at average concentration of 2.81ng/L but not detected in May 2012. By contrary, florfenicol was detected in all water samples in May 2012 at average concentration of 16.28ng/L but not detected in August 2011. Antibiotic resistant bacteria enumerated by antibiotic-containing agar plating showed higher abundance of resistant bacteria to tetracycline than florfenicol in both of the two sampling campaigns. The average number of tetracycline resistant bacteria in the surface water were 1.14×105 and 8.41×103 cells/mL in August and May, respectively. In term of florfenicol resistant bacteria, the average number were 1.61×102 and 5.88×102cells/mL in August and May, respectively. Although the numbers of these two resistant bacteria showed the same seasonal fluctuation pattern as the concentration of antibiotic in the surface water, no significant correlation was found between the concentration and the resistant bacteria abundance for any of the antibiotics in this study.