Antibacterial and Antibiofilm Activities of Ceragenins Alone and in Combination with Levofloxacin Against Multidrug Resistant Myroides spp. Clinical Isolates from Patients with Urinary Tract Infections

Myroides spp. are rare opportunistic pathogens, but they can be life-threatening because of their multidrug-resistant drug properties and their potential to cause outbreaks, especially in immunosuppressed patients. In this study, 33 isolates isolated from intensive care patients with urinary tract infections were examined for drug susceptibility. All isolates except three proved to be resistant to the tested conventional antibiotics. The effects of ceragenins, a class of compounds developed to mimic endogenous antimicrobial peptides, were evaluated against these organisms. The MIC values of nine ceragenins were determined, and the most effective ceragenins were CSA-131 and CSA-138. Three isolates that were susceptible to levofloxacin and two isolates resistant to all antibiotics underwent 16 s rDNA analysis, and whereas resistant isolates were identified as M. odoratus, susceptible isolates were identified as M. odoratimimus. CSA-131 and CSA-138 showed rapid antimicrobial effects observed in time-kill analyses. Combinations of ceragenins and levofloxacin caused a significant increase in antimicrobial and antibiofilm activities against M. odoratimimus isolates. In this study, Myroides spp. were found to be multidrug-resistant and have biofilm forming capacity, and ceragenins CSA-131 and CSA-138 were found to be especially effective on both planktonic and biofilm forms of Myroides spp.