残留剂量头孢曲松长期作用对SPF级Balb/c小鼠肠道菌群的影响

Effect of long term exposure to residual dose ceftriaxone on SPF Balb/c mice intestinal flora

目的研究残留剂量头孢曲松的长期作用对SPF级Balb/c小鼠肠道菌群的影响。方法通过随机饮水方式,连续45 d分别给予SPF小鼠3个浓度的低剂量头孢曲松,模拟残留剂量抗生素的持续作用,活菌计数研究菌群数量变化。结果 300μg/ml及30μg/ml头孢曲松水溶液持续作用,小鼠肠道菌群厌氧总菌、乳杆菌和肠杆菌数量均出现先降后升的趋势,而肠杆菌数量异常增殖,双歧杆菌数量显著减少(P<0.01)且无法恢复,肠球菌无显著变化(P>0.05);3μg/ml头孢曲松处理后小鼠肠道肠杆菌数量显著升高,其余检测细菌数量无显著影响(P>0.05)。结论 300、30及3μg/ml头孢曲松水溶液持续处理45 d均会导致小鼠肠道菌群失调,菌群失调程度与头孢曲松浓度密切相关。

Objective To study the effect of long term exposure to residual dose ceftriaxone on SPF Balb/c mice intestinal flora.Method SPF Balb/c mice were treated with drinking water containing 300 g/ml,30 g/ml and 3 μg/ml ceftriaxone respectively for 45 days so that to imitate the continuous effect of antimicrobial agent residues.Changes of mice fecal flora were detected by vital cell counting.Result The balance of microecology in murine feces was slightly broken in both 300 μg/ml and 30 μg/ml ceftriaxone treated groups.Except the enterococci,the numbers of anaerobe,lactobacilli and enteric bacteria reduced first but increased in the end.In contrast to the overgrowth of enteric bacterium,the numbers of bifidobacterium decreased remarkably and irreversibly.No obvious changes of fecal microbiota were observed in 3 μg/ml ceftriaxone treated group except the increase of the enteric bacteria.Conclusion Balb/c mice intestinal flora is disturbed by long term exposure to 300 μg/ml,30 g/ml and 3 μg/ml ceftriaxone.The extent of imbalance of the microbiota was closely related to antibiotic doses.