Analysis of the Pseudomonas aeruginosa Aminoglycoside Differential Resistomes Allows Defining Genes Simultaneously Involved in Intrinsic Antibiotic Resistance and Virulence

Abstract

High-throughput screening of transposon insertion libraries is a useful strategy for unveiling bacterial genes whose inactivation results in an altered susceptibility to antibiotics. A potential drawback of these studies is they are usually based on just one model antibiotic for each structural family, under the assumption that the results can be extrapolated to all members of said family. To determine if this simplification is appropriate, we have analyzed the susceptibility of mutants of Pseudomonas aeruginosa to four aminoglycosides. Our results indicate that each mutation produces different effects on susceptibility to the tested aminoglycosides, with only two mutants showing similar changes in the susceptibility to all studied aminoglycosides. This indicates that the role of a particular gene in the resistome of a given antibiotic should not be generalized to other members of the same structural family. Five aminoglycoside-hypersusceptible mutants inactivating glnD, hflK, PA2798, PA3016, and hpf were chosen for further analysis in order to elucidate if lower aminoglycoside susceptibility correlates with cross-hypersusceptibility to other antibiotics and with impaired virulence. Our results indicate that glnD inactivation leads to increased cross-susceptibility to different antibiotics. The mutant in this gene is strongly impaired in virulence traits such as pyocyanin production, biofilm formation, elastase activity, and swarming motility and the ability to kill Caenorhabditis elegans. Thus, GlnD might be an interesting target for developing antibiotic coadjuvants with antiresistance and antivirulence properties against P. aeruginosa.

Lactonase Specificity Is Key to Quorum Quenching in Pseudomonas aeruginosa

“…Several other protein levels showed differences between the two lactonase treatments. The abundance of five proteins (OprF, OprM, HflK, OmpH, and Ppk) were reduced only with SsoPox W263I while two others (OprD and OprH) were increased only with GcL treatment (Fraley et al, 2007;Dotsch et al, 2009;Lister et al, 2009;Hinz et al, 2011;Somprasong et al, 2012;Chevalier et al, 2017;Sanz-García et al, 2019).…”

The many antibiotic resistance and tolerance strategies of Pseudomonas aeruginosa

“…Target site modification (ribosomal in the case of aminoglycosides, or DNA gyrase in fluoroquinolones) has also been noted, leading to a lack of binding of the antibiotic to its target [ 27 , 33 ]. Antibiotic resistance can also be conferred through horizontal gene transfer, in which antibiotic modifying enzyme genes can be acquired by plasmid transfer from other species of bacteria [ 34 , 35 ]. Clinically, antibiotic resistance is a growing concern.…”

Coming from the Wild: Multidrug Resistant Opportunistic Pathogens Presenting a Primary, Not Human-Linked, Environmental Habitat

“…Lastly, from a One-Health perspective, it must be noted that P. aeruginosa ubiquity in nature aggravates the problem of AR. This bacterium has a broad sub-lethal selective window to different antibiotics, under which resistant mutants may arise [ 86 , 87 ]. This matter becomes more alarming since substantial concentrations of drugs (i.e., 31 or 61 mg/L of ciprofloxacin or tetracycline, respectively) have been detected in habitats that P. aeruginosa can colonize [ 23 , 88 ], besides clinical settings.…”