The rise of antibiotic resistance and the dwindling antimicrobial pipeline have emerged as significant threats to public health. The emergence of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a global threat, with limited options available for targeted therapy. The CRKP has experienced various changes and discoveries in recent years regarding its frequency, transmission traits, and mechanisms of resistance. In this comprehensive review, we present an in-depth analysis of the global epidemiology of K. pneumoniae, elucidate resistance mechanisms underlying its spread, explore evolutionary dynamics concerning carbapenem-resistant hypervirulent strains as well as KL64 strains of K. pneumoniae, and discuss recent therapeutic advancements and effective control strategies while providing insights into future directions. By going through up-to-date reports, we found that the ST11 KL64 CRKP subclone with high risk demonstrated significant potential for expansion and survival benefits, likely due to genetic influences. In addition, it should be noted that phage and nanoparticle treatments still pose significant risks for resistance development; hence, innovative infection prevention and control initiatives rooted in One Health principles are advocated as effective measures against K. pneumoniae transmission. In the future, further imperative research is warranted to comprehend bacterial resistance mechanisms by focusing particularly on microbiome studies’ application and implementation of the One Health strategy.

The misuse and mismanagement of antibiotics have made the treatment of bacterial infections a challenge. This challenge is magnified when bacteria form biofilms, which can increase bacterial resistance up to 1000 times. It is desirable to develop anti-infective materials with antibacterial activity and no resistance to drugs. With the rapid development of nanotechnology, anti-infective strategies based on metal and metal oxide nanomaterials have been widely used in antibacterial and antibiofilm treatments. Here, this review expounds on the state-of-the-art applications of metal and metal oxide nanomaterials in bacterial infective diseases. A specific attention is given to the antibacterial mechanisms of metal and metal oxide nanomaterials, including disrupting cell membranes, damaging proteins, and nucleic acid. Moreover, a practical antibiofilm mechanism employing these metal and metal oxide nanomaterials is also introduced based on the composition of biofilm, including extracellular polymeric substance, quorum sensing, and bacteria. Finally, current challenges and future perspectives of metal and metal oxide nanomaterials in the anti-infective field are presented to facilitate their development and use.

Neonatal meningitis Escherichia coli (NMEC) breaching the blood-brain barrier (BBB) is a critical event in the development of E. coli meningitis. Brain microvascular endothelial cells (BMECs), the primary structural component of the BBB, play a central role in defending against pathogen invasion. In this study, we employ the NMEC strain RS218 (O18:K1:H7) to investigate the molecular mechanisms of cell death in BMECs and its pivotal contribution to BBB disruption. The study reveals that RS218 infection promotes assembly of the Ripoptosome complex. This leads to the coordinated activation of apoptosis, pyroptosis, and necroptosis. Notably, necroptosis can also occur through RIPK1-independent pathways. By generating Ripk1 ^D138N/D138N, Gsdmd ^-/-, and Casp8 ^-/- Ripk3 ^-/- mice, we demonstrate that the regulation of BMECs death was an important factor in BBB resistance to infection. Among these models, kinase-dead Ripk1 ^D138N/D138N mice exhibit the most effective BBB protection, independent of innate immune responses. Inhibition of RIPK1 kinase significantly preserves BBB integrity, and lowers RS218 invasion and neuroinflammation. Moreover, the combination of RIPK1 inhibition with antibiotics yields additive therapeutic effects. Our study advances the understanding of NMEC pathogenesis and supports the potential of RIPK1 as a therapeutic target for E. coli meningitis.

A personalized biphasic microneedle patch with variable treatment regimens and an invisible drug delivery capability.

Carbapenem-resistant Klebsiella pneumoniae (CRKP), particularly those with high virulence, cause invasive disease in clinical settings. An epidemiological investigation was conducted on the evolution, virulence, and antimicrobial resistance of CRKP isolates in two tertiary teaching hospitals in Jiangsu, China from November 2020 to December 2021. There were 31 different CRKP strains discovered. We performed whole genome sequencing (WGS) on 13 SHV, cmlv, and FosA6-producing CRKP to reveal molecular characteristics. Five ST15/ST11 isolates had CRISPR-Cas systems. By conjugation tests, KPC-2 can be transmitted horizontally to E. coil. A conjugative pHN7A8-related multi-resistance plasmid (KPC-2, bla_CTX-M-65, bla_TEM-1, fosA3, catII, and rmtB) was first discovered in CRKP clinical isolates. Using bacteriological testing, a serum killing assay, and an infection model with Galleria mellonella, three ST11-K64 KPC-2 generating carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) were identified. These strains harbored a virulent plasmid and an IncFII-family pKPC/pHN7A8 conjugative plasmid, which led to hypervirulence and resistance. One of these CR-hvKPs, which co-harbored KPC-2, NDM-6, SHV-182, SHV-64, and bla_CTX-M-122 genes, was first discovered. Importantly, this CR-hvKP strain also produced biofilm and had non-inferior fitness. The widespread use of ceftazidime/avibactam might provide this CR-hvKP with a selective advantage; hence, immediate action is required to stop its dissemination. Another important finding is the novel ST6136 in K. pneumoniae. Finally, the sterilization efficiency rates of Fe₂C nanoparticles in CRKP were more than 98%. Furthermore, our novel antibacterial Fe₂C nanoparticles may also provide a therapeutic strategy for infections.