Carbapenem-resistant Klebsiella pneumoniae is a major threat to global health, with increasing incidence in developing countries, including Egypt. This study determined carbapenem-resistance prevalence among clinical K. pneumoniae isolates from two Egyptian tertiary hospitals, characterized the major carbapenemase genes, and assessed the transferability of the resistance plasmids. VITEK^® 2 and MALDI-TOF MS identified 94 non-duplicate isolates. Susceptibility was determined by Kirby–Bauer diffusion and VITEK^® 2. MICs of imipenem, meropenem and colistin were confirmed by broth microdilution. Isolates were classified as multidrug-resistant (MDR), extensively drug-resistant (XDR), or pandrug-resistant (PDR) according to established definitions. Phenotypic (modified Hodge test [MHT], modified carbapenem inactivation method [mCIM], modified Carba NP test [mCNP]) and genotypic (PCR/BlastN) evaluation of carbapenemase production and plasmid transferability by conjugation were carried out in 18 isolates, selected to represent every carbapenemase genotype identified in the collection. All isolates were MDR, and 94.68% were carbapenem-resistant and fulfilled the criteria for XDR, remaining susceptible only to colistin and tigecycline. Carbapenemase production was confirmed phenotypically in 98.9% and genotypically in 97.9% of isolates. bla_OXA-48 (94.7%) and bla_NDM-1 (69.1%) predominated, with 67.0% co-carriage; bla_KPC occurred in 5.3%. Conjugation transferred carbapenemase-encoding plasmids to Escherichia coli J53 from 77.8% (14/18) of donors, conferring carbapenem non-susceptibility in all transconjugants. All isolates were colistin-susceptible by broth microdilution, the reference method. The high XDR prevalence, along with the conjugative transferability of bla_OXA-48/bla_NDM-1, is consistent with a mobile carbapenemase-encoding plasmid reservoir in Egyptian tertiary care, highlighting the significance of carbapenemase surveillance and stewardship. Plasmid characterization and clonal typing were not performed and are required to define that reservoir fully.

The global threat of multidrug-resistant infections requires new approaches for its management. A blend of polymethyl methacrylate (PMMA) and poly(ε-caprolactone) (PCL) electrospun nanofibrous membrane was utilised as a scaffold to sustain the release of three broad-spectrum antiseptics to combat multidrug-resistant (MDR) microorganisms. The scaffold was characterised by Fourier transform infrared spectroscopy, contact angle, and scanning electron microscopy. The latter revealed a random and smooth structure. The contact angle value of 81.8 ± 1.8 confirmed the hydrophilic nature of the scaffold, which is important for wound healing. The high surface-to-volume ratio of the scaffolds was utilised for loading benzoic acid (BA), methylparaben (MPB), and propylparaben (PPB) which were released during 72 h concentrations ranging between 0.20 and 0.8 mg mL⁻¹. The initial release of antiseptics was high and was then sustained for over 72 h. After 8 h, the burst release was 61.64 ± 4.11% for BA, 41.11 ± 2.98% for MPB and 34.32 ± 3.13% for PPB. The release profile of BA was superior to that of the MPB and PPB. The loaded scaffolds inhibited MDR-resistant methicillin-resistant Staphylococcus aureus, Escherichia coli and Candida albicans and were not cytotoxic to a fibroblast cell line. They inhibited their colonisation by the tested microorganisms to non-detectable counts or at least reduced microbial counts by at least 6–7 logs (p ≤ 0.001) for 72 h. Crystal violet techniques and electron microscopy confirmed colonisation inhibition. Because of their non-cytotoxicity and broad-spectrum antimicrobial activity, the antiseptic-loaded PMMA/PCL nanofibrous scaffolds could be utilised as wound dressings, particularly in non-healing wounds.