Carbapenem-Resistant Klebsiella pneumoniae Clinical Isolates: In Vivo Virulence Assessment in Galleria mellonella and Potential Therapeutics by Polycationic Oligoethyleneimine

Abstract

Klebsiella pneumoniae, one of the most common pathogens found in hospital-acquired infections, is often resistant to multiple antibiotics. In fact, multidrug-resistant (MDR) K. pneumoniae producing KPC or OXA-48-like carbapenemases are recognized as a serious global health threat. In this sense, we evaluated the virulence of K. pneumoniae KPC(+) or OXA-48(+) aiming at potential antimicrobial therapeutics. K. pneumoniae carbapenemase (KPC) and the expanded-spectrum oxacillinase OXA-48 isolates were obtained from patients treated in medical care units in Lisbon, Portugal. The virulence potential of the K. pneumonia clinical isolates was tested using the Galleria mellonella model. For that, G. mellonella larvae were inoculated using patients KPC(+) and OXA-48(+) isolates. Using this in vivo model, the KPC(+) K. pneumoniae isolates showed to be, on average, more virulent than OXA-48(+). Virulence was found attenuated when a low bacterial inoculum (one magnitude lower) was tested. In addition, we also report the use of a synthetic polycationic oligomer (L-OEI-h) as a potential antimicrobial agent to fight infectious diseases caused by MDR bacteria. L-OEI-h has a broad-spectrum antibacterial activity and exerts a significantly bactericidal activity within the first 5-30 min treatment, causing lysis of the cytoplasmic membrane. Importantly, the polycationic oligomer showed low toxicity against in vitro models and no visible cytotoxicity (measured by survival and health index) was noted on the in vivo model (G. mellonella), thus L-OEI-h is foreseen as a promising polymer therapeutic for the treatment of MDR K. pneumoniae infections.

Multimodal Interventions to Prevent and Control Carbapenem-Resistant Enterobacteriaceae and Extended-Spectrum β-Lactamase Producer-Associated Infections at a Tertiary Care Hospital in Egypt

“…Infections with MDR organisms or the rising, extensive, drug-resistant Gram-negative bacteria including the carbapenem-resistant Enterobacteriaceae (CRE) and extended-spectrum β-lactamase (ESBL) producers remain the most challenging. This is because of their limited treatment options, their rapid spread among healthcare environments causing outbreaks associated with high mortality rates and their associated prolonged hospital stays with a high economic burden [ 2 , 3 , 4 ]. It is also estimated that by 2030, more than half of Klebsiella pneumoniae and Escherichia coli will be resistant to third-generation cephalosporins [ 5 ].…”

The Two Weapons against Bacterial Biofilms: Detection and Treatment

“…Antimicrobial polymers have been shown to be promising alternatives to combat microorganisms [ 105 , 106 ]. In particular, cationic polymers have been widely explored and shown to be highly efficient in killing both Gram-positive and Gram-negative bacteria [ 105 , 107 ].…”

“…Molecular weight might influence diffusion of polymers across lipid membrane and contribute to bacterial cell death. To mimic AMP mechanism, the synthesis of polymers often includes a cationic group to interact with negative membrane of bacterial cells [ 106 , 108 , 109 , 110 ]. Quaternary ammonium groups or quaternary phosphonium group has been explored as a cationic core in new synthetic polymers [ 110 ].…”

“…In addition, the authors concluded that cationic and amphiphilic (hydrophobic and hydrophilic balance) are, as expected, crucial for antibacterial activity [ 112 ]. The potential of oxazoline-based antimicrobial oligomers was explored in two distinct works [ 105 , 106 ]. Using supercritical CO 2 , a method that reduces the use of toxic reagents, Correia et al obtained biocompatible oxazoline-based oligomers quaternized with different amines [ 105 ].…”

New Insights on Biofilm Antimicrobial Strategies

“…Using a different approach, Mil-Homens et al reported the application of a synthetic polycationic oligomer (L-OEI-h) as an alternative to treat Klebsiella pneumoniae infections [13]. The authors showed that L-OEI-h caused lysis of the cytoplasmic membrane in a panel of different species.…”