Departamento de Biología de Organismos, Universidad Simón Bolívar (USB), Caracas, Venezuela.
Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela.
Lett Appl Microbiol. 2020 May;70(5):372-379. doi: 10.1111/lam.13283. Epub 2020 Mar 11.
Pseudomonas aeruginosa is a prominent member of emerging waterborne pathogens. The environmental reservoirs of multi-resistant phenotypes and other virulence factors in this bacterium are poorly understood. Our study aimed to determine the virulence properties of P. aeruginosa isolated from Roraima Sur Cave (RSC) waters at Guayana Highlands. Based on the best identification at species level by biochemical tests, 16S rRNA sequencing and phylogenetic inferences, one RSC isolate named LG11 was characterized for virulence properties in comparison with P. aeruginosa reference strains. PCR amplification of alginate, elastase, exoenzyme S, exotoxin A, neuraminidase and Quorum-Sensing genes showed a high virulence potential in LG11. This isolate demonstrated multi-resistance to ceftriaxone, tigecycline and imipenem. Pyocyanin production was greater in LG11 (0·478 µg ml ) than the strain ATCC 10145 (0·316 µg ml ), but the highest pigment concentration (2·140 µg ml ) was displayed by the clinical strain CVCM 937 (P = 0·000175). Pronounced biomass production on granite and glass (P < 0·05) and well-developed biofilms indicated the ability of P. aeruginosa from RSC to colonize surfaces found in human and healthcare environments. These data suggest that waters from pristine ecosystems such as RSC could be reservoirs of this opportunistic bacterium carrying important virulence properties with potential epidemiological implications. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows for the first time the occurrence of virulence genes and multi-resistance to antimicrobials in Pseudomonas aeruginosa isolated from cave waters at Guayana Highlands. These findings, together with the biofilm formation on surfaces found in human and healthcare settings, suggest public health risks and the potential of these virulence properties to be transferred from or to native populations in waters. Our results provide important insights to the current knowledge of P. aeruginosa in the environment, setting the basis for future studies driven to assess reservoirs of multi-resistant bacteria and virulence features unknown in pristine ecosystems.
铜绿假单胞菌是新兴水源性病原体中的重要成员。该细菌的多耐药表型和其他毒力因子的环境储库了解甚少。我们的研究旨在确定圭亚那高地罗赖马苏尔洞穴（RSC）水中分离的铜绿假单胞菌的毒力特性。根据生化试验、16S rRNA 测序和系统发育推断的最佳种水平鉴定，对分离株 LG11 进行了与铜绿假单胞菌参考株的毒力特性比较。藻酸盐、弹性蛋白酶、外毒素 S、外毒素 A、神经氨酸酶和群体感应基因的 PCR 扩增显示 LG11 具有高毒力潜力。该分离株对头孢曲松、替加环素和亚胺培南表现出多耐药性。LG11 的绿脓菌素产量（0.478μg/ml）高于 ATCC 10145 株（0.316μg/ml），但临床株 CVCM 937 的最高色素浓度（2.140μg/ml）（P=0.000175）。LG11 在花岗岩和玻璃上表现出明显的生物量生产（P<0.05）和良好的生物膜形成，表明 RSC 泉水来源的铜绿假单胞菌具有在人类和医疗保健环境中发现的表面定植的能力。这些数据表明，来自原始生态系统（如 RSC）的水可能是携带重要毒力特性的这种机会性病原体的储库，具有潜在的流行病学意义。研究的意义和影响：本研究首次表明，从圭亚那高地洞穴水中分离的铜绿假单胞菌携带毒力基因和对抗生素的多耐药性。这些发现，以及在人类和医疗保健环境中发现的表面形成的生物膜，表明存在公共卫生风险，并且这些毒力特性有可能从或转移到水中的本地人群。我们的研究结果为当前环境中铜绿假单胞菌的知识提供了重要的见解，为未来研究奠定了基础，这些研究旨在评估未知的多耐药菌和毒力特征在原始生态系统中的储库。
