培养法检测海滨浴场细菌多样性及耐药性研究

Diversity and antibiotic resistance of bacteria from bathing beaches: based on the cultivation method

摘要:

【目的】耐药基因细菌水平基因转移导致的耐药菌数量增加引发的公共安全问题日益引起人们关注，监测环境中耐药菌变得极为重要。【方法】采集湛江3处滨海浴场的水体、沙滩土样，通过平板稀释涂布和琼脂扩散法进行浴场微生物数量、多样性和抗生素耐药性分析。【结果】3处浴场水体无机氮含量偏高，浴场微生物数量随着客流量逐渐增加，沙滩中微生物数量显著高于水体。浴场细菌分布于3门12科18属，水体中变形菌门（Proteobacteria，49.64%）占优势，沙滩则是厚壁菌门（Firmicutes，54.74%）占优势。浴场细菌对β-内酰胺类耐药率较高，青霉素、万古霉素和头孢曲松耐药率分别达到23.25%、20.53%和17.42%，耐药菌株主要分布于芽孢杆菌属（Bacillus）、弧菌属（Vibrio）、假单胞菌属（Pseudomonas）、链霉菌属（Streptomyces）和肠杆菌属（Enterobacter），水体中多重耐药细菌数量显著高于沙滩，集中于人流量多的浴场。【结论】滨海浴场环境中细菌耐药菌种类多，需持续监测以评估对当前地区公共卫生的潜在影响。

关键词:滨海浴场;细菌多样性;抗生素耐药性;抗生素抗性细菌

Abstract:

[Objective] The increasing antibiotic resistant bacteria (ARB) caused by the horizontal transfer of antibiotic resistance genes (ARGs) have aroused increasing concern, and it is particularly important to monitor the ARB in the environment. [Methods] We collected seawater and sand samples from three different bathing beaches in Zhanjiang. The plate coating method and agar diffusion method were employed to study the bacterial counts, diversity, and susceptibility to antibiotics. [Results] The seawater samples had higher content of inorganic nitrogen than the normal value and the bacterial counts increased with the increase in the visitor flow. The bacteria counts in the sand samples were higher than those in the seawater samples. The bacteria from the bathing beaches belonged into 18 genera, 12 families of 3 phyla. Proteobacteria (49.64%) was dominant in the seawater samples, while Firmicutes (54.74%) was dominant in the sand samples. The bacteria showed stronger resistance to beta-lactams, with the resistance rates of 23.25%, 20.53%, and 17.42% to penicillin, vancomycin, and ceftriaxone, respectively. The resistant bacteria were mainly Bacillus, Vibrio, Pseudomonas, Streptomyces, and Enterobacter. The multidrug-resistant bacterial strains from seawater were significantly more than those from sand, and increased with the increase in the visitor flow. [Conclusion] There are diverse drug-resistant bacteria from bathing beaches, and continuous surveillance is required to assess its potential impact on public health.

Key words:bathing beach;bacterial diversity;antibiotic resistance;antibiotic-resistant bacteria