Dear Colleagues,

This Special Issue is the continuation of our previous special issue "Virulence and Resistance of Klebsiella pneumonia".

Klebsiella pneumoniae is an important opportunistic Gram-negative pathogen that belongs to the Enterobacteriaceae family, which is frequently associated with severe healthcare-associated infections (HAI) as well as community-acquired infections. It can cause different types of infection such as pneumonia, urinary tract infection, skin or soft tissue infection, meningitis, pyogenic liver abscess, and bacteremia potentially developing into sepsis. It is believed that the gastrointestinal tract is the most important reservoir for the transmission of K. pneumoniae. However, in contrast to many other bacterial pathogens, K. pneumoniae is ubiquitous in nature, and environmental reservoirs can also have a relevant role in human infections. Infections resulting from multidrug-resistant (MDR), extended-spectrum beta-lactamase (ESBL), and/or carbapenemase-producing K. pneumoniae strains are a challenge due to the lack of vaccines and therapeutic options. Several virulence factors, such as adherence and invasion factors, toxins, capsules, and siderophores, can be involved in the pathogenic mechanisms, namely, invasion of the host, disease induction, and the evasion of host defenses. The coexistence of antimicrobial resistance genes with other advantageous determinants such as virulence factors can have a significant impact on bacterial pathogenicity. Moreover, recent population diversity studies have shown that K. pneumoniae is in fact part of a complex of species. The aim of this Special Issue is to give an updated insight into K. pneumonia-complex resistance and virulence determinants, and the interplay of these factors. For this purpose, we welcome the submission of research articles, review articles, and short communications related to the various aspects of K. pneumonia-complex infection, with particular emphasis on antimicrobial resistance, its transmissibility, molecular pathways, the coexistence of virulence factors, biomarkers, clinical and environmental reservoirs, high-risk clones, whole genome sequencing characterization, in vivo infection models, and bacterial pathogenicity.

Dr. Aida Duarte
Dr. Cátia Caneiras
Guest Editors

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