AUTHOR=Fabrizio Giorgia , Sivori Francesca , Cavallo Ilaria , Truglio Mauro , Toma Luigi , Sperati Francesca , Francalancia Massimo , Obregon Francisco , Pamparau Luisa , Kovacs Daniela , Pimpinelli Fulvia , Di Domenico Enea Gino 

TITLE=Efficacy of sodium hypochlorite in overcoming antimicrobial resistance and eradicating biofilms in clinical pathogens from pressure ulcers

JOURNAL=Frontiers in Microbiology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2024.1432883

DOI=10.3389/fmicb.2024.1432883

ISSN=1664-302X

ABSTRACT=<p>Sodium hypochlorite (NaOCl) is widely recognized for its broad-spectrum antimicrobial efficacy in skin wound care. This study investigates the effectiveness of NaOCl against a range of bacterial and fungal isolates from pressure ulcer (PU) patients.</p><p>We analyzed 20 bacterial isolates from PU patients, comprising carbapenem-resistant <italic>Klebsiella pneumoniae</italic> (CRKP), multidrug-resistant Acinetobacter baumannii (MDRAB), methicillin-resistant <italic>Staphylococcus aureus</italic> (MRSA), methicillin-susceptible <italic>Staphylococcus aureus</italic> (MSSA), along with 5 <italic>Candida albicans</italic> isolates. Antibiotic resistance profiles were determined using standard susceptibility testing. Whole-genome sequencing (WGS) was employed to identify antimicrobial resistance genes (ARGs) and disinfectant resistance genes (DRGs). Genetic determinants of biofilm formation were also assessed. The antimicrobial activity of NaOCl was evaluated by determining the minimum inhibitory concentration (MIC) and the minimal biofilm eradication concentration (MBEC) for both planktonic and biofilm-associated cells.</p><p>CRKP and MDRAB showed resistance to fluoroquinolones and carbapenems, while MRSA exhibited resistance to β-lactams and levofloxacin. MSSA displayed a comparatively lower resistance profile. WGS identified significant numbers of ARGs in CRKP and MDRAB, with fewer DRGs compared to MRSA and MSSA. All isolates possessed genes associated with fimbriae production and adhesion, correlating with pronounced biofilm biomass production. NaOCl demonstrated substantial antimicrobial activity against both planktonic cells and biofilms. The MIC<sub>90</sub> for planktonic bacterial cells was 0.125 mg/mL, and the MBEC<sub>90</sub> ranged from 0.225 to 0.5 mg/mL. For planktonic C. <italic>albicans</italic>, the MIC<sub>90</sub> was 0.150 mg/mL, and the MBEC<sub>90</sub> was 0.250 mg/mL.</p><p>These results highlight the challenge in treating biofilm-associated infections and underscore the potential of NaOCl as a robust antimicrobial agent against difficult-to-treat biofilm infections at concentrations lower than those typically found in commercial disinfectants.</p>