| dc.description.abstract | Pseudomonas aeruginosa is a common cause of respiratory infections particularly in immunocompromised people and patients with chronic diseases such as cystic fibrosis. Gentamicin, an aminoglycoside, is a frequently used antibiotics in treating P. aeruginosa infections including chronic ones. However long-term exposure to antibiotics in chronic infection treatment can trigger not only the development of antimicrobial resistance (AMR) but also other characteristics of the pathogens including virulence, thus affecting treatment outcome. In this study, gentamicin-exposed P. aeruginosa (Ge-E1 and Ge-E2) strains were assessed for the virulence change in comparison to the unexposed strain (Pseudomonas aeruginosa ATCC 9027) via analyzing the change in production of pyocyanin, pyoverdine, elastase, and rhamnolipid using biochemical methods. Besides, expression of the virulence-related genes mvaT, rhlB, phzM were also investigated using RT-qPCR. Obtained results showed that gentamicin exhibited a suppressing effect on pyocyanin, pyoverdine, and rhamnolipid secretion. However, gentamicin was unable to stop P. aeruginosa from producing elastase. All virulence saw a recovery in production after gentamicin was terminated, either at a lower (pyocyanin, rhamnolipid) or comparable amount (pyoverdine, elastase) compared to the non-antibiotic-treated strain. The molecular assessment consistently gave a decreasing tendency in all tested mvaT, rhlB, phzM genes in both Ge-E1 and Ge-E2 strains. Based on the RT-qPCR result, while the trend in rhlB was similar to the lack of rhamnolipid production observed in the phenotypic test, phzM exhibited conflicting results with the pyocyanin assay. In conclusion, gentamicin exposure resulted in reduced virulence production in P. aeruginosa. This suggested that gentamicin could be used in long-term P. aeruginosa infection treatment. | en_US |
