W. Elkhatib

14 th International Phytocosmetics and Phytotherapy Congress

Molecular and phenotypic profiles of carbapenem- and third-generation cephalosporin-resistant Klebsiella pneumoniae isolates from the fecal microbiota of pediatric patients with COVID-19

Gut colonization with multidrug-resistant (MDR) Klebsiella pneumoniae is commonly associated with an increased risk of extraintestinal infections among hospitalized patients. Extensive antibiotic exposure during the COVID-19 pandemic, is a critical contributing factor for the emergence of resistant strains. This investigation sought to elucidate the phenotypic and molecular resistance traits of carbapenem-resistant K. pneumoniae (CRKP) and extended-spectrum β-lactamase–producing K. pneumoniae (ESBL-KP) colonizing the gut of pediatric patients with confirmed COVID-19. A cross-sectional study was conducted from October 2020 to March 2022 at a tertiary pediatric hospital in Fayoum, Egypt. Fecal samples were collected from hospitalized pediatric COVID-19 patients. K. pneumoniae isolates were identified using standard microbiological methods. Antimicrobial susceptibility testing was carried out in accordance with the CLSI guidelines. ESBL and carbapenemase production were assessed phenotypically, while resistance genes were detected by multiplex and uniplex PCR. Microtiter plate method was used to assess biofilm formation. K. pneumoniae was detected in 36 of 71 patients (50.7%) using antibiotic-supplemented selective culture. The isolated strains were exclusively resistant, including 22 CRKP and 14 ESBL-KP. Colistin susceptibility was maintained in all isolates. CRKP strains showed significantly increased rate of resistance to fluoroquinolones and amikacin compared with ESBL-KP. BlaNDM gene (54.5%) and blaKPC (45.5%) were detected among CRKP isolates. ESBL-associated genes blaCTX-M, blaTEM, and blaSHV were prevalent in both groups. Biofilm formation was common and comparable between CRKP and ESBL-KP isolates. A high prevalence of fecal carriage of MDR K. pneumoniae, driven by carbapenemase-producing strains, was observed among hospitalized pediatric COVID-19 patients. These outcomes highlight the necessity for routine colonization surveillance, optimized antimicrobial stewardship, and strengthened infection control strategies in pediatric settings.

Cold and hot tumors: immunological determinants, cancer-immunity cycle dysregulation, and nanotechnology-driven therapeutic approaches

Cancer remains a major global health burden and the second leading cause of mortality worldwide. Recent advances in cancer immunotherapy have emphasized the critical role of the tumor microenvironment (TME) in determining therapeutic outcomes, leading to the classification of tumors into immunologically “hot” and “cold” phenotypes. Cold tumors are characterized by low immunogenicity, limited immune cell infiltration, and a highly immunosuppressive microenvironment, resulting in poor prognosis and resistance to immune checkpoint inhibitors. Despite the development of multiple immunotherapeutic strategies, effective activation of antitumor immunity in cold tumors remains a major clinical challenge. Current approaches aim to initiate immune responses through priming strategies such as cancer vaccines and adoptive T-cell transfer, while simultaneously overcoming immunosuppressive signaling via immune checkpoint blockade. Additional strategies include depletion of myeloid-derived suppressor cells and enhancement of co-stimulatory pathways. However, these approaches are often limited by inefficient delivery, poor tumor penetration, and systemic toxicity. Nanotechnology has emerged as a promising platform for tumor microenvironment reprogramming. Nanocarriers enable targeted delivery of immunomodulatory agents, enhance antigen presentation, and improve immune activation while overcoming biological barriers such as dense stroma and abnormal vasculature. By integrating nanotechnology with immunotherapy, new opportunities arise to convert cold tumors into hot, immune-responsive phenotypes, thereby improving therapeutic efficacy and clinical outcomes.