Due to the nature of Vibrio vulnificus infections (i.e., gastroenteritis and septicemia), only very few studies of a biofilm-associated form in this pathogen's life cycle have been conducted. We proposed that biofilm production by clinical strains of V. vulnificus would be higher than by environmental strains. Biofilm formation by clinical and environmental reference strains was tested under different temperatures (24, 30, and 37 °C), pH (5.5, 7.5, and 8.5) and iron concentrations (18, 30, 50, 100, and 200 μM). Biofilm production by clinical strains was consistently higher (p < 0.001) at 24 °C than by environmental strains. Higher biofilm production was observed at pH 5.5 by all strains. Growth rates were lowest at pH 5.5 for environmental strains but for clinical strains there were no differences at pH 5.5, 7.5, and 8.5, demonstrating a tolerance to acidic and alkaline conditions. There was a strong, direct correlation between iron concentration in the growth medium and biofilm production by all strains tested. The current study indicates that biofilm formation might be important for the survival of V. vulnificus in vivo as well as in the marine environment. With regard to temperature and pH, higher biofilm production appears to be a trait of clinical strains and could be considered a virulence determinant in V. vulnificus.

中文翻译：

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温度，pH和铁对创伤弧菌临床菌株与环境菌株对生物膜形成的影响。

由于创伤弧菌感染的性质（即肠胃炎和败血病），在这种病原体的生命周期中，很少进行与生物膜相关形式的研究。我们提出临床创伤弧菌的生物膜生产将比环境菌株高。在不同温度（24、30和37°C），pH（5.5、7.5和8.5）和铁浓度（18、30、50、100和200μM）下测试了由临床和环境参考菌株形成的生物膜。临床菌株在24°C下的生物膜产量始终高于环境菌株（p <0.001）。所有菌株在pH 5.5下观察到更高的生物膜产量。对于环境菌株，pH值为5.5时生长速率最低，而对于临床菌株，pH 5.5、7.5和8.5时无差异，表现出对酸性和碱性条件的耐受性。在所有测试菌株中，生长培养基中的铁浓度与生物膜产量之间存在很强的直接相关性。目前的研究表明，生物膜的形成可能对V. vulnificus在体内以及在海洋环境中的生存很重要。关于温度和pH，更高的生物膜产量似乎是临床菌株的特征，并且可以被认为是创伤弧菌的毒力决定因素。