Virulence properties and antimicrobial resistance of Pseudomonas aeruginosa isolated from cave waters at Roraima Tepui, Guayana Highlands

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−1) than the strain ATCC 10145 (0·316 µg ml−1), but the highest pigment concentration (2·140 µg ml−1) was displayed by the clinical strain CVCM 937 (P = 0·000175). Pronounced biomass production on granite and glass (P