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.

• Klíčová slova
• Galleria mellonella infection model, KPC and OXA-48-like carbapenemases, Klebsiella pneumoniae, linear oligoethyleneimine hydrochloride,
• Publikační typ
• časopisecké články MeSH

The level of lysozyme in fat body, hemocytes and cell-free hemolymph from Galleria mellonella larvae infected with Pseudomonas aeruginosa was determined and evaluated. In the samples of fat body and hemocytes, an increase in lysozyme content was detected 1 d after infection and then a significant decrease was observed after a prolonged infection time. In the case of cell-free hemolymph, an increase in the lysozyme level was noticeable during the first 30 h post injection and stayed at a similar level for 42 h. The smaller decrease of the lysozyme level after 42 h might be associated with the development of bacteremia of P. aeruginosa in insects. In addition, the gradual increase in the content of lysozyme correlated with the increase of its activity in the hemolymph of the infected larvae as a response to injection with P. aeruginosa. The G. mellonella lysozyme appeared to be insensitive to extracellular proteinases produced in vivo by P. aeruginosa.

• MeSH
• hemocyty enzymologie   MeSH
• hemolymfa enzymologie   MeSH
• hmyzí proteiny metabolismus   MeSH
• larva enzymologie   mikrobiologie   MeSH
• muramidasa metabolismus   MeSH
• můry enzymologie   mikrobiologie   MeSH
• Pseudomonas aeruginosa fyziologie   MeSH
• tukové těleso enzymologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hmyzí proteiny MeSH
• muramidasa MeSH