Abstract
Pseudomonas aeruginosa is a Gram-negative γ-proteobacterium that forms part of the normal human microbiota and it is also an opportunistic pathogen, responsible for 30% of all nosocomial urinary tract infections. P. aeruginosa carries a highly branched respiratory chain that allows the colonization of many environments, such as the urinary tract, catheters and other medical devices. P. aeruginosa respiratory chain contains three different NADH dehydrogenases (complex I, NQR and NDH-2), whose physiologic roles have not been elucidated, and up to five terminal oxidases: three cytochrome c oxidases (COx), a cytochrome bo3 oxidase (CYO) and a cyanide-insensitive cytochrome bd-like oxidase (CIO). In this work, we studied the composition of the respiratory chain of P. aeruginosa cells cultured in Luria Broth (LB) and modified artificial urine media (mAUM), to understand the metabolic adaptations of this microorganism to the growth in urine. Our results show that the COx oxidases play major roles in mAUM, while P. aeruginosa relies on CYO when growing in LB medium. Moreover, our data demonstrate that the proton-pumping NQR complex is the main NADH dehydrogenase in both LB and mAUM. This enzyme is resistant to HQNO, an inhibitory molecule produced by P. aeruginosa, and may provide an advantage against the natural antibacterial agents produced by this organism. This work offers a clear picture of the composition of this pathogen’s aerobic respiratory chain and the main roles that NQR and terminal oxidases play in urine, which is essential to understand its physiology and could be used to develop new antibiotics against this notorious multidrug-resistant microorganism.
Highlights
Pseudomonas aeruginosa is a Gram-negative, rod shaped γ-proteobacteria that colonizes a large diversity of environments, such as soil, water, and forms part of the normal microbiota of humans, animals and plants [1,2]
Pseudomonas aeruginosa respiratory chain is responsible for one third of all nosocomial urinary tract infections (UTI), which greatly increase the risk of morbidity and mortality in septic shock patients and diabetic patients [6] and are commonly associated with the use of contaminated catheters [7,8]
P. aeruginosa PAO1 strain was cultured aerobically in modified artificial urine media, to simulate the conditions that the planktonic state of this microorganism might encounter in the urinary tract or in catheters when they start the colonization process
Summary
Pseudomonas aeruginosa is a Gram-negative, rod shaped γ-proteobacteria that colonizes a large diversity of environments, such as soil, water, and forms part of the normal microbiota of humans, animals and plants [1,2]. P. aeruginosa has an enormous repertoire of molecular mechanisms that allow its adaptation to the environment, including a flexible metabolism that plays an essential role in its capability to colonize diverse niches. This bacterium is a facultative anaerobe with a highly branched respiratory chain that uses either oxygen or nitrogen oxides as final electron acceptors [10,11,12] and that under aerobic conditions uses oxidative phosphorylation, rather than fermentation, to produce ATP [4,11,12]. In addition to the quinol oxidases, the respiratory chain contains cytochrome bc and three cytochrome c oxidases (COx): caa, cbb and cbb (Fig 1A) [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
