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Background/Objectives: This study aimed to characterize the epidemiology, resistance, virulence determinants, and genomic relatedness of OXA-48-producing Klebsiella pneumoniae in a secondary-care hospital in north-eastern Italy, and to assess the in vitro activity of cefepime-based β-lactam/β-lactamase inhibitor combinations. Methods: We performed a retrospective observational study of consecutive, non-duplicate isolates (September 2024–January 2025). Susceptibility testing was performed using VITEK^® 2 and MIC TestStrip. All isolates underwent single-read Nanopore whole-genome sequencing, with assembly and in silico detection of resistance genes, porin alterations, plasmid replicons and virulence loci. Core-genome single-nucleotide polymorphism analysis with recombination filtering assessed genetic relatedness. Results: Thirteen isolates were recovered from elderly, highly comorbid inpatients, mainly from urine (46.2%) and rectal/fecal screening (38.5%). Twelve patients were classified as colonized, whereas one patient had an infection due to OXA-48-producing K. pneumoniae, with the organism recovered from both blood and urine cultures. All belonged to sequence type 395 and carried blaOXA-48 and blaCTX-M-15, together with a truncated OmpK35 and an OmpK36 loop-3 GD insertion. The yersiniabactin locus ybt16 within integrative conjugative element ICEKp12 was detected in 92.3% of isolates. Core-genome analysis showed high genomic similarity among isolates, consistent with local circulation of an ST395 lineage. Although yersiniabactin may contribute to iron acquisition and bacterial fitness, its presence alone does not establish a hypervirulent phenotype or predict clinical virulence. In the absence of aerobactin, salmochelin, rmpADC, and rmpA2, and without phenotypic virulence testing, these isolates should be regarded as yersiniabactin-positive but non-hypervirulent based on their genomic profile. Core-genome analysis indicated close genetic relatedness among the isolates, consistent with possible local clonal circulation. In a subset, cefepime/enmetazobactam and especially cefepime/zidebactam substantially reduced cefepime minimum inhibitory concentrations. Conclusions: We identified a multidrug-resistant OXA-48-producing K. pneumoniae ST395 lineage circulating locally, predominantly in colonization contexts. Active screening and genomic surveillance may support infection control and inform the potential role of emerging cefepime-based inhibitor combinations. Full article

Extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae causes difficult-to-treat bloodstream infections in patients with haematological malignancies, particularly after allogeneic haematopoietic stem cell transplantation (allo-HSCT). Carbapenems remain reliable, but their anti-anaerobic activity may aggravate intestinal dysbiosis and increase selection pressure for carbapenem resistance. Cefepime–enmetazobactam is a novel fourth-generation cephalosporin/β-lactamase inhibitor combination active against many class A ESBL-producing Enterobacterales. We describe a profoundly immunocompromised patient with acute myeloid leukaemia after allo-HSCT, grade III steroid-refractory gastrointestinal graft-versus-host disease, and intestinal colonization by an ESBL-producing K. pneumoniae isolate resistant to ceftolozane–tazobactam. The patient developed persistent bacteraemia and right pyelonephritis with small renal abscess-like lesions. Meropenem was rapidly de-escalated to cefepime–enmetazobactam, with temporary adjunctive fosfomycin and subsequently tigecycline. Blood-culture time to positivity progressively lengthened from 1.18 h to 16 h before cultures became negative. Serial cefepime therapeutic drug monitoring permitted repeated assessment of exposure and neurological toxicity risk. Whole-genome sequencing identified K. pneumoniae ST307 carrying bla_CTX-M-15, bla_TEM-1, bla_SHV-28, and bla_OXA-1, together with multiple resistance determinants and a large conjugative plasmid. This case describes the use of cefepime–enmetazobactam as part of a targeted carbapenem-sparing strategy for invasive ESBL-producing K. pneumoniae infection in a highly immunocompromised allo-HSCT recipient. Full article

Aflatoxin contamination remains a critical challenge for food and feed safety, necessitating effective mitigation strategies. This study addresses the challenge of aflatoxin contamination by identifying four novel bacterial candidates capable of degrading four major aflatoxin congeners (B1, B2, G1, and G2). Quantitative HPLC and qualitative LC-HRMS with MS/MS profiling revealed that the isolated bacterial strains achieved high degradation efficiencies of 86–94%, proceeding through distinct demethylation and decarboxylation pathways. Oxford Nanopore whole-genome sequencing identified these potent degraders as Escherichia coli EC_2 and Klebsiella pneumoniae (KP_4, KP_5, and KP_6). To elucidate the genomic basis of this phenotype, we performed a comparative genomic analysis against two non-degrading E. coli strains. Functional annotation revealed complete aromatic degradation modules and intact enzymatic cascades present only in the degrading strains, demonstrating that this biodegradation capability is highly strain specific. Furthermore, molecular docking of key putative enzymes unique to these active cascades demonstrated highly favorable binding affinities (up to −8.70 kcal/mol) with all four aflatoxin congeners, stabilized by robust hydrogen bonding and hydrophobic networks. These findings provide a novel genomic and structural blueprint for aflatoxin biotransformation, highlighting the specific putative candidate enzymes, paaH and mhpB, for future investigations. Full article

Camelus dromedarius (the dromedary camel) plays a vital role in the lives, food security, and culture of pastoral people in many arid and semi-arid areas of Africa, the Middle East, and South Asia. Despite their economic and nutritional value, camels are poorly represented in veterinary pharmacology, with limited numbers of antimicrobial agents formally licensed for use in this species. These practitioners and owners therefore depend heavily on off-label and extra-label administration of drugs developed and dosed for cattle, small ruminants or humans. This narrative review synthesizes published work related to antimicrobial use in dromedary camels, highlighting the pharmacokinetic uncertainties of extrapolating doses from other species. This review distinguishes between direct dromedary data and indirect evidence from other camelids, as well contextual practices within mixed livestock systems to fill evidence gaps. It addresses the non-clinical aspect of suboptimal antimicrobial use, such as under-analgesia, irrational dosing and untimely or off-formal treatment. It also discusses the ever-expanding literature on antimicrobial-resistant bacteria found in camel-derived products, camel ticks and camel feces, such as the presence of ESBL and MDR E. coli, Klebsiella pneumoniae, and Staphylococcus spp. The findings are discussed in the context of the One Health paradigm, and possible routes of camel-to-human exposure through raw milk and meat, as well as environmental dissemination of resistance genes, are recommended for surveillance and stewardship. Full article

The African boxthorn (Lycium ferocissimum) is a medicinal plant belonging to the Solanaceae family that is used in traditional pharmacopeia. Here, its biological potential was assessed by analyzing the essential oil from its leaves (EOLF), extracted by hydro-distillation and major terpenes characterized by gas chromatography coupled to mass spectrometry (GC-MS). GC-MS analysis of EOLF identified fourteen compounds representing 99.95% of the total mass, which was dominated by carvacrol (35.96%) and sabinene (17.06%). EOLF exhibited antioxidant activity as characterized by several assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric Reducing Antioxidant Power (FRAP), Total Antioxidant Capacity (TAC) and the β-carotene/linoleic acid test. According to the results obtained, EOLF exhibited antioxidant activity, as measured by the DPPH assay, with a mean IC₅₀ of 96 µg/mL, which is relatively close to that of quercetin (74 µg/mL) and BHT (49.16 µg/mL). Furthermore, the activity assessed using the FRAP method showed an EC₅₀ of 282 µg/mL, comparable to that of BHT (292 µg/mL). Based on the results of the TAC method, the antioxidant activity was 880 ± 4 µg AAE/mg, while the efficacy for inhibition of β-carotene was 80%. Effective antimicrobial activity against several bacterial and fungal strains was assessed by measuring inhibition zones and Minimum Inhibitory Concentrations (MICs). EOLF exhibited significant antimicrobial activity, particularly against Klebsiella pneumoniae, with an inhibition zone of 25.08 ± 0.93 mm and an MIC of 15.68 ± 0.83 µg/mL. For Staphylococcus aureus, an inhibition zone of 23.84 ± 0.88 mm and an MIC of 11.03 ± 0.27 µg/mL were recorded. Strong antifungal activity was also observed against Candida albicans, with an inhibition zone of 22.55 ± 0.87 mm and an MIC of 10.51 ± 0.47 µg/mL. The conducted in-silico analysis confirmed the affinity of the main compounds with key biological targets, suggesting their likely roles in the observed antimicrobial effects. The ADEM-Tox properties demonstrated that the analyzed compounds would only be lethal at very great concentrations, indicating low acute toxicity, and would not be expected to elicit toxic effects at therapeutic doses. Full article

Background. Rational design of phage cocktails typically relies on the lytic spectrum. However, susceptibility criteria vary widely among studies, ranging from qualitative lysis in spot tests to quantitative endpoints based on serial-dilution titration or efficiency of plating. Methods. We investigated this discrepancy using four commercial phage cocktails and two capsule-specific monophages against a clinically representative collection of 448 Klebsiella pneumoniae isolates comprising 56 capsule types, collected in 2018–2025 from 12 medical centers. Using a modified Gratia titration assay, we defined host range (HR) as specific lysis at any dilution and putative therapeutic applicability (PTA) as lysis at dilutions corresponding to ≥10⁶ plaque-forming units per mL. Results. We identified a systematic discrepancy between these two measures of cocktail efficacy. HR coverage reached 64%, whereas PTA was significantly lower, with a median HR–PTA difference of 36%. This discrepancy persisted for capsule-specific monophages tested against KL2 isolates (n = 69), indicating that neither nominal capsule matching nor low component titres fully explained the loss of activity. This pattern provides indirect functional evidence that post-adsorption barriers contribute to the HR–PTA discrepancy, although adsorption and intracellular antiphage mechanisms were not assessed directly. Capsule type was the principal and most robust predictor of efficacy, whereas spatiotemporal factors, including year and medical centre, had only a weak effect on PTA. Conclusions. Capsule matching can therefore help estimate population-level coverage but does not fully predict high-titre activity. Phage selection should incorporate serial-dilution testing rather than rely on spot-test lysis alone. Cocktail design should account for both receptor coverage and functional activity against representative isolates within individual capsule types. Full article

Carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a substantial public health threat worldwide. This trend is undoubtedly exacerbated by biofilm formation, which is closely related to bacterial virulence. Small RNAs (sRNAs) are post-transcriptional regulators of many biological processes in bacteria, including biofilm formation and virulence. The purpose of this study was to investigate the regulatory mechanisms of a novel sRNA (sRNA002) on biofilm formation and the virulence of CRKP. Through the CRISPR-Cas9 gene editing system, proteomic sequencing, real-time quantitative polymerase chain reaction (RT-qPCR), crystal violet staining, scanning electron microscopy, hydrophobicity assay, a mouse intraperitoneal infection model, and the green fluorescent protein reporter system, we confirmed that the knockout of sRNA002 significantly downregulated the expression of the mrkA and mrkB genes, and weakened the virulence and biofilm formation ability of CRKP. Full article

Antimicrobial resistance is a growing global crisis that threatens to return humanity to a pre-antibiotic era where common infections become deadly. This narrative review synthesizes evidence from 2000 to early 2026, including Global Research on Antimicrobial Resistance data and World Health Organization surveillance, to outline the problem’s scale, drivers, and solutions. In 2019, bacterial resistance directly caused 1.27 million deaths and was linked to 4.95 million more. Low- and middle-income countries bear the heaviest burden. ESKAPE pathogens, especially carbapenem-resistant Acinetobacter baumannii and NDM-producing Klebsiella pneumoniae, drive intensive care unit mortality near 50% and cause untreatable neonatal sepsis. One Health drivers include antibiotic overuse in humans, with 30% of prescriptions unnecessary in high-income settings; agriculture, consuming 70% of global antibiotics; and environmental pollution, with resistance genes found in 72% of rivers. Bacteria spread resistance through horizontal gene transfer and mutations such as gyrA S83L, creating pan-drug-resistant strains that make surgeries, transplants, and cancer treatment risky. Economic modeling studies suggest that unchecked antimicrobial resistance could reduce annual global GDP by 1.1–3.8%, with some scenarios projecting losses of up to approximately 5% by 2050, depending on assumptions about healthcare costs, labor productivity, and livestock production. Solutions require subscription-based payment models, enforceable agricultural regulations, integrated genomic surveillance, and equity-focused diagnostics for low- and middle-income countries. Without binding 2030 targets, the post-antibiotic era would become a clinical reality within a decade. Full article

Klebsiella pneumoniae (K. pneumoniae) belongs to the genus Klebsiella of the Enterobacteriaceae family. In goats, K. pneumoniae infection can result in respiratory diseases such as pneumonia and bronchopneumonia. In this study, caprine bronchial epithelial cells were infected with K. pneumoniae, and multi-omics integration analysis was conducted to investigate the immune defense mechanisms triggered by the infection. Enrichment analysis of differentially expressed genes (DEGs) using the KEGG database revealed that immune-related signaling pathways involving TNF and IL-17 were among the top 20 most enriched. Based on the TNF and IL-17 signaling pathways, ten immune pathway-related genes, including CCL20, CXCL1, TRAF4, FOS, IL6, PTGS2, TNF, CXCL8, TNFAIP3, and JUN, were selected for RT-qPCR validation. In addition, four miRNAs targeting genes involved in the above pathways, namely chi-miR-148a-5p, miR-1285-z, miR-16-x, and miR-6119-x, were verified by RT-qPCR. The expression trends of chi-miR-148a-5p and miR-1285-z were consistent with microRNA sequencing results. Furthermore, gain- and loss-of-function experiments indicated that chi-miR-148a-5p may target TNF and PTGS2, while miR-1285-z may target NFKBIZ, with CSF2 predicted as a potential target. This study suggests that chi-miR-148a-5p and miR-1285-z may participate in the TNF and IL-17 signaling pathways by regulating their predicted target genes. Moreover, the TNF and IL-17 signaling pathways are among the most highly enriched immune-related pathways involved in the innate immune response of caprine bronchial epithelial cells. This study provides insights into the molecular mechanisms underlying immune responses in goats infected with K. pneumoniae. Full article

Background/Objectives: Antimicrobial resistance (AMR) constitutes a major public health and economic burden in contemporary society. This work aims to identify the patterns and temporal trends of Klebsiella pneumoniae resistance to carbapenems across several European countries. Methods: Data on K. pneumoniae resistance to carbapenems in several countries from 2005 to 2021 (with data available up to 2023) were retrieved from the public ECDC website in 2023. Agglomerative Hierarchical Cluster Analysis (HCA), based on the new generalised affinity coefficient, was applied to the estimated ARIMA models. Results: The dendrogram at the cut-off presented four clusters: the first cluster with Slovenia, Luxembourg, Italy and Estonia; the second cluster with Romania, Malta, Greece, Portugal and Spain; the third cluster Denmark, France and Czechia; and finally the fourth cluster with Lithuania, Cyprus, Finland, Austria, Belgium and Slovakia. Although the resistance values showed an increasing trend over the years in clusters II and III, the increase was more pronounced in cluster II. Conclusions: The application of data analysis, for the first time, using HCA based on a new similarity coefficient, namely, the generalised affinity coefficient, enables the evaluation of time-series patterns in different regions and enables the identification of clusters of countries showing similar temporal patterns of antimicrobial resistance. Carbapenem resistance in K. pneumoniae among countries belonging to cluster II showed increasing trends throughout the study period. Full article

Urinary tract infections (UTIs) represent a major global health burden, traditionally defined as microbial invasion of a sterile urinary tract, but now increasingly understood as a state of microbial dysbiosis involving disruption of the urinary microbiome. This review aims to synthesize current knowledge on the molecular mechanisms, etiological agents, clinical classification, and emerging therapeutic strategies in UTIs. The analysis integrates recent advances in microbiome research, molecular pathogenesis, and clinical guidelines. Uropathogenic Escherichia coli (UPEC) remains the predominant pathogen, utilizing virulence factors such as adhesins and intracellular bacterial community formation to establish persistent infection, while other organisms including Klebsiella pneumoniae, Proteus mirabilis, and Enterococcus faecalis contribute to disease complexity. The emergence of multidrug-resistant organisms, particularly among ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), poses significant therapeutic challenges through mechanisms such as β-lactamase production, efflux pumps, and biofilm formation. Clinically, evolving classification systems emphasize infection localization rather than host factors, improving diagnostic and therapeutic precision. Diagnostic strategies rely on clinical assessment, urinalysis, and urine culture, while treatment increasingly incorporates antimicrobial stewardship principles. Emerging approaches, including immunoprophylaxis, bacteriophage therapy, and microbiome-targeted interventions, demonstrate promising results. In conclusion, UTIs are complex, multifactorial diseases requiring integrated molecular, clinical, and therapeutic approaches, with future advancements likely driven by precision medicine and artificial intelligence. Full article

Hypervirulent Klebsiella pneumoniae (hvKP) causes invasive infections, including bloodstream infections and liver abscesses, and dysregulated host inflammation may exacerbate liver injury. We investigated whether pretreatment with Humanin, a mitochondria-derived anti-inflammatory peptide, could attenuate hvKP-associated liver injury. We measured serum Humanin in 20 patients with hvKP-associated bloodstream infection and liver abscess and 20 matched healthy controls. C57BL/6 mice received intraperitoneal Humanin (2.5 or 5 mg/kg/day) for five days before intravenous hvKP challenge. We assessed liver injury, inflammatory responses, hepatic transcriptomes, NF-κB activation, and survival. Serum Humanin was higher in patients than in the controls (p < 0.001). In infected mice, Humanin pretreatment was associated with less prominent histopathological liver injury and lower serum ALT, AST, and PCT, hepatic myeloperoxidase activity, F4/80 immunoreactivity, CD86 fluorescence, and pro-inflammatory gene expression. The effects were generally greater at 5 mg/kg than at 2.5 mg/kg. Transcriptomic analysis showed attenuation of inflammatory pathways, including NF-κB signaling (NES = −1.86, p = 0.002, FDR = 0.012). Humanin also reduced p-p65/p65 and p-IκBα/IκBα ratios in liver tissue and hvKP-stimulated bone-marrow-derived macrophages; 5 mg/kg prolonged survival (p < 0.05). Humanin pretreatment may therefore limit inflammatory liver injury during systemic hvKP infection. This effect was associated with reduced macrophage-associated inflammation and NF-κB activation, although its molecular targets remain unknown. Full article

Objectives: The study determined antimicrobial resistance profiles of surgical wound multidrug-resistant (MDR) isolates belonging to the ESKAPE group and evaluated antibacterial and antibiofilm activities of geraniol (G), carvacrol (C) and eugenol (E), individually and in the selected mixtures. The cytotoxicity of monoterpenes and combinations was also assessed. Methods: The antibacterial and antibiofilm activity against tested isolates of Enterococcus faecium, Staphylococcus aureus MRSA, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter sp. was assessed in microdilution and crystal violet assay, respectively, while cytotoxicity was estimated in XTT assay on human MRC-5 fibroblasts. Results: C showed the strongest antibacterial activity (MIC 0.32 ± 0.24 mg mL⁻¹). Monoterpenes induced synergism in certain combinations (FICI 0.09–0.31). All individual monoterpenes inhibited biofilm formation, but G was the most active (38.78–84.72%, p < 0.05). The most pronounced biofilm eradication was observed for C (25.21–61.34%, p < 0.05). G-C mixtures showed notable inhibition of biofilm formation in all isolates except P. aeruginosa, but, on the contrary, induced biofilm eradication against P. aeruginosa only. Cytotoxicity was not detected with the applied concentrations of monoterpenes, while the G-C mixtures exhibited lower cytotoxicity than povidone-iodine (p < 0.05) used as the control. Conclusions: All monoterpenes and G-C mixtures proved significant antibacterial and antibiofilm potential against ESKAPE isolates and acceptable impact on cell viability. Practical significance: The results highlight the potential of plant monoterpenes and their binary combinations as complementary agents for controlling MDR ESKAPE pathogens and biofilm-associated infections following surgical procedures. Further in vivo and safety studies are needed to confirm their applicability in clinical settings. Full article

Background: Hypervirulent Klebsiella pneumoniae (K. pneumoniae) easily causes bacteremia and liver abscess, and invades the eye via blood circulation to trigger blinding endogenous endophthalmitis. Widespread multidrug resistance limits antibiotic treatment, while traditional capsular polysaccharide vaccines cannot provide cross-serotype protection. Methods: We established a mouse model of intraperitoneal infection-induced endogenous endophthalmitis. BALB/c mice received two intramuscular injections of LNP-encapsulated PstS-YidR fusion mRNA vaccine, followed by challenge with hypervirulent K1 or K2 strains. We monitored body weight, quantified multi-tissue bacterial loads, detected IL-1β, IL-6 and TNF-α, and performed slit-lamp observation and liver/ocular histopathology. Results: The vaccine relieved systemic symptoms and weight loss, suppressed bacterial dissemination across peritoneal, blood, liver, lung and eye tissues, and reduced excessive inflammatory factor release. It alleviated intraocular suppurative lesions, preserved ocular structure, and mitigated liver abscess and hepatocellular necrosis, with equal protective efficacy against K1 and K2 and favorable in vivo safety. Conclusions: The PstS-YidR fusion mRNA vaccine blocks systemic spread and intraocular invasion of hypervirulent K. pneumoniae and alleviates multi-organ inflammatory damage. It serves as a safe candidate vaccine for preventing K1/K2-type hypervirulent Klebsiella infections and endogenous endophthalmitis. Full article

Przewalski’s gazelle (Procapra przewalskii) is an endangered ungulate endemic to the Qinghai–Tibet Plateau of China. Increasing habitat alteration and close contact with domestic livestock have raised concerns about cross-species pathogen transmission, yet infectious disease studies in this species remain limited. To determine the etiology of illness in two deceased gazelles from a conservation facility in Qinghai Province, we screened samples for a panel of pathogens, including Mycoplasma ovipneumoniae, Clostridium perfringens toxin genes, Mannheimia haemolytica, Klebsiella pneumoniae, Mycoplasma capricolum subsp. capripneumoniae, Pasteurella multocida, Peste des petits ruminants virus (PPRV), Bovine viral diarrhea virus (BVDV), and Infectious bovine rhinotracheitis virus (IBRV), using PCR and RT-PCR. BVDV-specific nucleic acids were detected in tissue samples from both individuals, whereas all other targeted pathogens tested negative. The virus was successfully isolated in Madin–Darby Bovine Kidney (MDBK) cells and confirmed by RT-PCR, followed by whole-genome sequencing of the isolate, which was designated QH PSYL 2026. Phylogenetic analysis based on the full-length genome and 5′UTR sequences assigned the isolate to the BVDV-1c subgenotype. Notably, its 5′UTR sequence shared 100% identity with those of local cattle-derived BVDV strains, providing molecular evidence suggestive of an epidemiological linkage between wildlife and livestock. Integrating clinical signs, gross pathology, and laboratory results, the cases were consistent with BVDV infection as the primary presumptive etiology. To our knowledge, this is the first report of BVDV infection, virus isolation, and genomic characterization in Przewalski’s gazelle. The detection of a BVDV-1c strain in this endangered species highlights the potential threat that livestock-associated pathogens pose to wildlife on the Qinghai–Tibet Plateau. These findings furnish crucial baseline data for disease surveillance, molecular epidemiology, and conservation management of Przewalski’s gazelle and provide valuable scientific evidence for wildlife disease prevention and control in plateau ecosystems. Full article