Abstract
Simple SummaryCarbapenem-resistant Klebsiella pneumoniae (CR-KP) infection rates represent a challenging treatment since the pipeline for effective antibiotics against this pathogen, such as beta-lactams among others, is practically nil. This study aims to evaluate the antibacterial effect of gold nanostars (GNS) alone or associated with some of the most widely used antibiotics for the treatment of CR-KP strains, i.e., meropenem or amikacin, on both planktonic or free-living and sessile forms. GNS were able to inhibit the planktonic growth of CR-KP at 80 µM, to eradicate the bacterial viability at 160 µM, and were unable to inhibit or eradicate the biofilm growth of this bacterium. GNS gave rise to filamentous bacteria through mechanisms mediated by the inhibition of energy-dependent cytoplasmic proteases. The combination of GNS and amikacin was able to inhibit or even eradicate the CR-KP biofilm. This combination was administered to greater wax moth larvae (Galleria mellonella), and this treatment was found to be tolerated well and to prevent the CR-KP infection. Thus, GNS in combination with amikacin represent a promising anti-CR-KP nanomaterial.(1) Background: Carbapenem-resistant Klesiella pneumoniae (CR-KP) infection rates depict an almost pre-antibiotic scenario since the pipeline for effective antibiotics against this pathogen has been almost entirely depleted. This study aims to evaluate the antibacterial effect of gold nanostars (GNS) alone or associated with some of the most widely used antibiotics for the treatment of CR-KP strains, i.e., meropenem or amikacin, on both planktonic and sessile forms. Additionally, we measured the effect of GNS on cell proliferation and biocompatibility in invertebrate in vivo models. (2) Materials and methods: GNS were made from gold seeds grown using a seeded-growth surfactant-free method assisted by silver ions and functionalized with mercapto-poly(ethylene glycol)amino by ligand exchange. The antimicrobial capacity, effect on cell proliferation, and biocompatibility of the most effective combination was evaluated in a Galleria mellonella model. (3) Results: The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were 80 and 160 µM of GNS for all strains, respectively. The minimum biofilm inhibitory concentration (MBIC) and minimum biofilm eradication concentration (MBEC) were >320 µM of GNS for both. A synergy was found between GNS and amikacin. Larvae administered GNS plus amikacin were found to tolerate the treatment well, which prevented infection. (4) Conclusions: GNS are a promising anti-CR-KP nanomaterial.
Highlights
Klebsiella pneumoniae is a Gram-negative, non-motile, aerobic rod-shaped encapsulated bacterium
This study aims to evaluate the antibacterial effect of gold nanostars (GNS) alone or in association with meropenem or amikacin, two of the most widely used antibiotics for the treatment of three carbapenem-resistant K. pneumoniae strains on both planktonic and sessile forms
We studied the effect of GNS on fibroblastic proliferation and biocompatibility in Galleria mellonella larvae in vivo models
Summary
Klebsiella pneumoniae is a Gram-negative, non-motile, aerobic rod-shaped encapsulated bacterium. This species is considered an opportunistic pathogen capable of colonizing mucosal surfaces without causing infection. This bacterium is present in the stools of 5%. To 38% and in the nasopharynx of 1% to 6% of individuals in the general community [1]. This microorganism can spread to other tissues, causing life-threatening infections. K. pneumoniae is the second leading cause of bloodstream infections caused by Gram-negative bacteria [2]. Multi-drug-resistant K. pneumoniae is one of the most vexing issues in bacterial resistance [5]. Most mechanisms of K. pneumoniae antibiotic resistance are acquired through horizontal gene transfer and mainly confer high-level resistance to antibiotics of the beta-lactam and quinolone types
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 call
