Meropenem/vaborbactam activity against carbapenem-resistant Klebsiella pneumoniae from catheter-related bloodstream infections.

Co-infection with carbapenem-resistant Klebsiella pneumoniae (CRKP) and Pseudomonas aeruginosa (CRPA) is associated with poor outcomes and historically relied on combination therapy with toxic agents for management. However, several novel β-lactam/β-lactamase inhibitor combination agents have been developed, offering potential monotherapy options. Here, we compare the in vitro activity of ceftazidime-avibactam (CZA), imipenem-relebactam (IRL), and meropenem-vaborbactam (MVB) against both CRKP and CRPA clinical isolates. Minimum inhibitory concentrations (MICs) for each agent were determined using broth microdilution. Carbapenemase gene detection was performed for representative isolates of varying carbapenem resistance phenotypes. IRL demonstrated excellent activity against CRKP and CRPA with susceptibility rates at 95.8% and 91.7%, respectively. While CZA and MVB showed comparable susceptibility to IRL against CRKP (93.8%), susceptibility of CRPA to CZA was modest at 79.2%, whereas most CRPA strains were resistant to MVB. Of the 35 CRKP isolates tested, 91.4% (32/35) carried a blaKPC gene. Only 1 of 37 (2.7%) CRPA isolates tested carried a blaVIM gene, which conferred phenotypic resistance to all three agents. None of the CRKP strains were cross-resistant to all three agents. Source of infection and co-infection did not significantly influence antimicrobial activity for IRL and CZA; none of the CRPA isolates from co-infected patients were susceptible to MVB. Our results suggest that novel β-lactam agents with antipseudomonal activity and stability against carbapenemases, such as IRL and CZA, offer potential monotherapy options for the treatment of co-infection involving both CRKP and CRPA, but not MVB.

Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a major pathogen responsible for urinary tract infections (UTIs). However, its role and characteristics in recurrent urinary tract infections (rUTIs) remain poorly understood. Investigating its features in rUTIs may provide insights into effective prevention strategies. We analyzed a cohort of patients with rUTIs caused by Klebsiella pneumoniae from April 2020 to April 2024. Antibiotic susceptibility of the isolates was evaluated. Biofilm Formation Assay and Galleria mellonella infection models were employed to assess the virulence of the strains. Polymerase Chain Reaction (PCR) and whole-genome sequencing (WGS) were utilized to determine multilocus sequence typing (MLST) and capsular serotyping, as well as to identify resistance genes, virulence genes, and plasmid replicons. Phylogenetic relationships among the isolates were also established. A total of 41 patients with rUTIs were included, with 56.1% caused by CRKP. 97.01% of CRKP carry the blaKPC-2 gene. Compared to patients infected with carbapenem-susceptible Klebsiella pneumoniae (CSKP), those infected with CRKP had a higher prevalence of underlying diseases and complications. Both groups of strains exhibited a high degree of antibiotic resistance. CRKP strains demonstrated enhanced biofilm formation capacity and greater lethality in Galleria mellonella infection models. The predominant phenotype of the CRKP strain was ST11 KL64, whereas the CSKP strain showed multiple phenotypes in different patients. Sequencing analyses revealed that both groups of strains carried a wide range of virulence genes, resistance genes, and plasmid replicons. Among the cases of rUTIs, 31 were identified as relapses caused by the same strain, with no significant differences between the initial and final infection strains. This study demonstrates that patients with rUTIs caused by CRKP present significant complexity in terms of clinical features, strain resistance and virulence properties. When managing UTIs caused by CRKP, special care needs to be taken to manage recurrent infections.

Objective: To characterize the antibiotic resistance and virulence in a carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods: A CRKP (designated K. pneumoniae C35) was isolated from a stool sample. The minimal inhibitory concentrations of antimicrobial agents were determined using the broth microdilution method. Whole-genome sequencing and genome analysis were performed to identify the antibiotic resistance and virulence genes. The genetic relationship among K. pneumoniae C35 and other CRKP isolates from our hospital was analyzed by single nucleotide polymorphism (SNP) typing of core genomes. Conjugation experiments were carried out by filter mating to evaluate the transferability and efficiency of resistance genes. The virulence phenotype was determined by Galleria mellonella infection model. Results: K. pneumoniae C35 exhibited resistance to the majority of tested antibiotics, especially carbapenems, sulbactam, and polymyxins. SNP typing showed that K. pneumoniae C35 shared a high degree of sequence homology with several CRKP isolates from different wards. This ST11 CRKP carried 13 resistance genes, including blaKPC-2, blaCTX-M-199, mcr-1, and tet(A) variant. blaKPC-2 gene was located on an IncFⅡ plasmid with>69 800 bp in size, blaCTX-M-199 and mcr-1 genes were located on an IncI2 plasmid (>64 800 bp), and tet(A) variant was located on an unknown Inc-type plasmid (83 628bp). All these three plasmids were conjugative. K. pneumoniae C35 was found to harbor rmpA, rmpA2, and iucABCD aerobactin-related genes, and was considered to be classic carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP). The virulence potential of this strain was confirmed in a Galleria mellonella infection model. The survival rate of the larvae injected with strain C35 at 48 h after infection was significantly lower than that of negative control strain (16.7% vs 80.0%). Conclusion: Multiple conjugative plasmids are identified in a faecal CR-hvKP. The IncI2 plasmid co-carrying both blaCTX-M-199 and mcr-1 genes is firstly identified in CR-hvKP. The emergence of such strain should be alerted and active surveillance is warranted.

To analyze the pathogen distribution and prognostic risk factors of catheter-related bloodstream infection (CRBSI) in patients with maintenance hemodialysis (MHD) during non-hospitalization. A retrospective comparative study was conducted. Thirty-four patients of MHD with semi-permanent catheter admitted to the department of nephrology of Gansu Provincial Hospital from January 2020 to May 2023 due to CRBSI during non-hospitalization were enrolled. The distribution characteristics of pathogens causing CRBSI in MHD patients during non-hospital period were analyzed. All patients were actively given anti-infection treatment after admission. The general data, laboratory indicators and prognosis during hospitalization were collected through the electronic medical record system. Patients were divided into poor prognosis group (14 cases) and good prognosis group (20 cases) according to the treatment results during hospitalization. Univariate and binary Logistic regression were used to analyze the risk factors affecting the prognosis of patients, and receiver operator characteristic curve (ROC curve) was drawn to evaluate its predictive value for prognosis. A total of 28 pathogenic bacteria were isolated from 34 patients, of which 25 were Gram-positive, Staphylococcus was the most common pathogen, accounting for 82.15% of the total, and 16 strains of Staphylococcus aureus (57.15%), including 6 methicillin-resistant Staphylococcus aureus (MRSA, 21.43%). There were 7 strains of Staphylococcus epidermidis (25.00%), including 3 strains of methicillin-resistant Staphylococcus epidermidis (MRSE, 10.71%). There were 3 strains of Gram-negative bacteria, 1 strain each of Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii. Univariate analysis showed that the fever duration of MHD patients with CRBSI in the poor prognosis group was significantly longer than that in the good prognosis group [days: 8.50 (3.75, 45.00) vs. 2.50 (1.00, 4.75), P < 0.01], serum erythrocyte sedimentation rate (ESR), C-reactive protein (CRP) and random blood glucose (GLU) were significantly higher than those in the good prognosis group [ESR (mm/1 h): 82.36±24.98 vs. 56.95±35.65, CRP (mg/L): 123.45±74.10 vs. 67.35±55.22, GLU (mmol/L): 8.74±3.66 vs. 6.42±1.95, all P < 0.05]. Binary Logistic regression analysis showed that serum CRP was an independent risk factor for poor prognosis in MHD patients with CRBSI [odds ratio (OR) = 1.020, 95% confidence interval (95%CI) was 1.002-1.038, P = 0.025]. ROC curve analysis showed that the area under the curve (AUC) of serum CRP in predicting poor prognosis of MHD patients with CRBSI was 0.711; when the optimal cut-off value was 104.65 mg/L, the sensitivity was 64.3% and the specificity was 85.0%, indicating that it has good predictive value. Gram-positive bacteria are the main pathogens of CRBSI in MHD patients during non-hospital period. The poor prognosis is mainly related to the high level of serum CRP. Serum CRP level can effectively screen the high-risk group of MHD patients with CRBSI with poor prognosis.

Hospital-acquired infections caused by multidrug-resistant (MDR) pathogens such as Methicillin-resistant Staphylococcus aureus (MRSA) and Carbapenem-resistant Klebsiella pneumoniae (CRKP) are a major health concern. In this study, ceftizoxime (CEF) and curcumin (CUR) were co-encapsulated into niosome nanoparticles (using thin-film hydration), and then embedded into a 3D-printed gelatin-alginate scaffold (Nio-CUR/CEF@SC). The Nio-CUR/CEF@SC were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR). The antibacterial activity was assessed using MIC, time-kill, and disc diffusion assays, while anti-biofilm activity was evaluated using crystal violet (CV) and minimum biofilm eradication concentration (MBEC) assays. Gene expression of virulence and resistance genes was measured using qRT-PCR, and cytotoxicity was tested via MTT assay on HFF cells. The Nio-CUR/CEF@SC system exhibited high encapsulation efficiency (CUR:78%; CEF: 80%), uniform nanoscale size (208–308 nm), and sustained dual-drug release over 72 h. This formulation reduced MIC values against MRSA and CRKP to 0.25–1 µg/mL (over 64-fold improvement vs. free drugs), produced large inhibition zones (up to 31.5 mm), and achieved strong time-kill and anti-biofilm effects (> 2 log₁₀ CFU/mL reduction). It also led to significant downregulation of MRSA ((hla, hlb, pvl)_ and CRKP (blaTEM, blaCTXM, blaOXA-48) virulence/resistance genes and showed > 90% viability on normal fibroblasts at effective doses. This study demonstrates that 3D-printed Nio-CUR/CEF@SC is an effective drug delivery system for the treatment of MRSA and CRKP infections in vitro. The engineered nanocarrier has potential for further research on infection therapies and offers a promising approach to combat drug-resistant pathogens.

In light of the increasing prevalence of carbapenem-resistant Klebsiella pneumoniae (CRKP), which represents asignificant public health threat, it is imperative to investigatenovel therapeutic strategies. This study aims to assess the efficacyof the novel antimicrobial peptide FP-CATH against CRKP, elucidateits potential mechanism of action, evaluate its safety profile andinfluencing factors, and determine whether FP-CATH possesses anti-inflammatoryproperties. A total of 15 CRKP strains (comprising 6 KPC2, 6 NDM-1,and 3 KPC2 + NDM-1) and 8 carbapenem-susceptible K.pneumoniae (CSKP) strains were selected for testing.The broth microdilution method was employed to ascertain the minimuminhibitory concentration (MIC) and minimum bactericidal concentration(MBC) of FP-CATH against these strains. The ability of FP-CATH todisrupt established CRKP biofilms was assessed by using crystal violetstaining. The mechanism of action of FP-CATH was investigated by usingNPN and PI fluorescent probes. Serum coincubation experiments wereconducted to evaluate the serum stability of FP-CATH. Additionally,RT-qPCR was utilized to measure the expression of inflammatory factorgenes in bacterially infected cells. Finally, the efficacy of FP-CATHwas validated in vivo using a Galleria mellonella infection model.

Background: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is a multidrug-resistant (MDR) gram-negative bacterium frequently involved in hospital-acquired pneumonia. The infection caused by this superbug has spread quickly in health centers worldwide, leading to high mortality rates. Due to this emerging scenario, the World Health Organization has categorized CRKP as the highest-priority species for the development of new compounds. In this context, antimicrobial peptides (AMPs) stand out as prototypes for alternative antimicrobials against superbugs, including CRKP. Objectives: We aimed to describe the antibacterial effect of an AMP (LyeTx I), derived from the venom of the spider Lycosa erythrognatha, against CRKP in vitro and in a murine pneumonia model. Results: LyeTx I showed antibacterial effects against all the CRKP clinical isolates tested, with a minimum inhibitory concentration (MIC) range of 2-8 µM and a minimum bactericidal concentration (MBC) range of 2-16 µM. The microbial anionic membrane was the primary target of LyeTx I, which acts by displacing divalent cations bound to this structure in a manner similar to that of polymyxins. Notably, LyeTx I displayed significant lytic activity against mimetic membranes, indicating its potential to disrupt bacterial cell integrity. In in vivo assays, the LyeTx I peptide proved to be safe at a dose of 10 mg/kg. In addition, intraperitoneal use of LyeTx I reduced the bacterial load and inflammation in the lungs of animals infected with a hypervirulent strain of CRKP. Conclusions: These results indicate that LyeTx I is a potential prototype for the development of new antibacterials against MDR species, such as CRKP.

Development of a lytic bacteriophage BPK01 impregnated biopolymer (chitosan) hydrogel for combating high-risk strains of carbapenem resistant Klebsiella pneumoniae (CRKP) pathogens- in vitro and in vivo evaluation.

ObjectiveTo analyze the molecular epidemiology and antimicrobial resistance profiles of carbapenem-resistant Klebsiella pneumoniae (CR-KP) isolates in Ningbo, with the aim of providing a theoretical basis for hospital infection control strategies and the implementation of precise clinical diagnosis and treatment protocols.MethodsDuring the period from April 30, 2023 to June 30, 2024, clinical isolates of Klebsiella pneumoniae were collected from multiple centers in Ningbo, including The Affiliated Li Huili Hospital (Yinzhou District, Ningbo), Xiangshan Red Cross Taiwan Compatriot Hospital Medical and Health Group (Xiangshan, Ningbo), and the Second Hospital of Ninghai County (Ninghai, Ningbo). A total of 81 CR-KP strains were identified using the broth dilution method for carbapenem resistance screening. These isolates were submitted to Beijing Novo gene Co., Ltd. for sequencing analysis. The sequencing data were analyzed using online tools (https://bigsdb.pasteur.fr/ and http://genepi.food.dtu.dk/resfinder) to obtain information on multilocus sequence typing (MLST), capsular serotype (KL type), virulence genes, and resistance genes. Phylogenetic relationships were constructed using SNP software. For plasmid characterization, the PlasmidFinder online tool (https://cge.food.dtu.dk/services/PlasmidFinder/) was utilized to identify plasmid replicon genes and perform Inc. typing analysis. Furthermore, to conduct a comprehensive collinearity analysis of the blaKPC-2 resistance plasmid gene, gene cluster maps were constructed using Bakta v1.11.0 and Clinker v0.0.28 software packages.ResultsAmong the 81 CR-KP isolates, MLST typing revealed that ST11 was the predominant sequence type, accounting for 66.67% (54/81), with KL64 being the dominant capsular type. Among the non-ST11 CR-KP isolates, the ST15 type accounted for 48.15% (13/27), with KL19 being the predominant capsular serotype. The carriage rate of virulence genes—including rmpA2, fyuA, and 10 other genes—was significantly higher in ST11 CR-KP compared to non-ST11 CR-KP (p < 0.05). Analysis of resistance genes revealed that ST11 CR-KP primarily carried blaKPC-2 (100%, 54/54), whereas the resistance gene profiles among non-ST11 CR-KP isolates were more diverse, including blaNDM, blaIMP, and blaOXA. Plasmid typing indicated that ST11 CR-KP predominantly harbored IncFII (98.15%, 53/54) and RepB (72.22%, 39/54) plasmid types. In contrast, non-ST11 CR-KP isolates exhibited a wider range of plasmid types, including IncX3 (33.33%, 9/27), RepB (25.93%, 7/27), IncFII (25.93%, 7/27), IncFIB (7.41%, 2/27), and both ColKP3 and Col440II (7.41%, 2/27). Antimicrobial susceptibility testing demonstrated high resistance rates to commonly used antibiotics in both ST11 and non-ST11 CR-KP isolates. ST11 CR-KP exhibited 100% resistance to six antibiotics, including ceftriaxone (CRO), cefotetan (CTT), and cefepime (FEP), and showed susceptibility only to gentamicin (GEN), aztreonam/avibactam (AZA), ceftazidime/avibactam (CZA), polymyxin B (POL), and tigecycline (TGC). Non-ST11 CR-KP showed a significantly higher resistance rate to gentamicin (GEN) and ceftazidime/avibactam (CZA) than ST11 CR-KP (p < 0.05), but lower resistance rates to cefotetan (74.07%), all of which were statistically significant (p < 0.05).ConclusionIn the Ningbo region, CR-KP is predominantly of the ST11-KL64 type, exhibiting both strong antimicrobial resistance and high virulence characteristics. Non-ST11 CR-KP isolates carry genetically diverse carbapenemase genes and mobile genetic elements (e.g., IncX3, ColKP3). ST11 CR-KP strains demonstrate significantly stronger resistance profiles compared to non-ST11 strains. Therefore, stringent control over the use of carbapenem antibiotics is essential, along with measures to prevent the spread of resistance plasmids and the continuous improvement of hospital infection control strategies.

ObjectiveThe traditional approaches for diagnosing catheter-related bloodstream infection(CRBSI) is time consuming, which could not meet the clinical requirement. Our aim was to investigate the value of serum procalcitonin(PCT) in predicting CRBSI in first-ever acute ischemic stroke patients with central venous catheters (CVCs).MethodsThis was a retrospective study. First-ever acute ischemic stroke patients hospitalized in neurological intensive care unit(NICU) of Aerospace Center Hospital and NICU of Beijing Chaoyang Hospital during January 2010 and December 2017 with clinically suspected CRBSI were enrolled. Peripheral blood white blood cell (WBC) count, neutrophils percentage(NE%), the levels of serum PCT, dwell time of catheterization and outcome of the patients were collected. According to the diagnosis of CRBSI or not, they were divided into CRBSI group and no CRBSI group. We used receiver operating characteristic curve (ROC) to evaluate the value of serum PCT levels in predicting CRBSI in patients with clinically suspected CRBSI.ResultsForty-five patients with suspected CRBSI were included in this study, and 13 patients were diagnosed with CRBSI. Comparing to those in no CRBSI group, the maximum body temperature (Tmax) (p = 0.036) and the PCT levels (P = 0.013) in CRBSI group were both significantly higher. The area under ROC of the serum PCT levels and the Tmax to predict the CRBSI were 0.803 (0.95CI,0.660–0.946) and 0.680 (0.95CI,0.529–0.832) respectively. The PCT cut-off value was 0.780 ng/ml, with the sensitivity 69.23%, specificity 87.50%, positive predictive values 69.23% and negative predictive values 87.50%.ConclusionIt could be helpful to adopt PCT as a rapid diagnostic biomarker for first-ever acute stroke patients with suspected CRBSI.

PurposeThe activity of the cationic antimicrobial peptide WLBU2 was evaluated against planktonic cells and biofilms of multi-drug resistant (MDR) Acinetobacter baumannii and Klebsiella pneumoniae, alone and in combination with classical antimicrobial agents.MethodsControl American Type Culture Collection (ATCC) strains and MDR clinical isolates of A. baumannii and K. pneumoniae were utilized. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of WLBU2 alone and in combination with antimicrobials were determined by classical methods. The Calgary biofilm device was used to determine the minimum biofilm eradication concentration (MBEC). The MTT assay was used to determine the cytotoxicity of agents on eukaryotic cells. The electrophoretic mobility shift assay was used to evaluate the ability of WLBU2 to bind bacterial DNA.ResultsThe WLBU2 MIC and MBC values were identical indicating bactericidal activity. The MIC/MBC values ranged from 1.5625 to 12.5 µM. At these concentrations, Vero cells and human skin fibroblasts were viable. The MBEC of WLBU2 ranged from 25 to 200 µM. A significant loss of eukaryotic cell viability was observed at the MBEC range. The combination of sub-inhibitory concentrations of WLBU2 with amoxicillin-clavulanate or ciprofloxacin for K. pneumoniae, and with tobramycin or imipenem for A. baumannii, demonstrated synergism, leading to a significant decrease in MIC and MBEC values for some isolates and ATCC strains. However, all combinations were associated with considerable loss in eukaryotic cells’ viability. WLBU2 did not demonstrate the ability to bind bacterial plasmid DNA.ConclusionWLBU2 in combination with antimicrobials holds promise in eradication of MDR pathogens.

To fight the global epidemic of drug-resistant bacteria, essential oils have gained increasing attention as a new source of antibiotics. The antimicrobial activity of Monarda didyma essential oils (MDEO) for the Carbapenem-resistant Klebsiella pneumoniae (CRKP) strains were determined by agar disc diffusion assay and broth microdilution assay. To further understand MDEO efficacy, a time-growth curve was performed. The biofilm formation of CRKP were determined by crystalline violet staining method, additionally, changes in intracellular Adenosine triphosphate (ATP), protein, Alkaline phosphatase (AKP) activities, and membrane integrity were investigated to assess the influence of MDEO on cell membrane damage. Finally, the activities of key enzymes in the tricarboxylic acid (TCA) pathways and pentose phosphate (PPP) pathways were examined to determine the effect of MDEO on the respiratory metabolism of CRKP. This study presents the antibacterial mechanism of MDEO against CRKP with a minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 1.25 mg/ml. To understand MDEO efficacy, a time-kill kinetics approach was performed. The bactericidal effect of MDEO was evident at 2 h compared to the control at its MIC and 2MIC. Surface electron microscopic and ATP assay studies provided evidence for the multi-target action of MDEO against CRKP. MDEO could inhibit CRKP biofilm formation. MDEO could also cause irreversible damage to the CRKP cell membrane, resulting in the leakage of biological macromolecules (protein, ATP) and the reduction of intracellular enzymes (AKP) activities. Finally, MDEO affected the pathways of respiratory metabolism, such as PPP and TCA pathways. MDEO could reduce the activity of key enzymes (Glucose-6-phosphate dehydrogenase, citrate synthase, isocitrate dehydrogenase, and α-ketoglutarate dehydrogenase) in the PPP and TCA pathways to exert its biological effects against CRKP. These results suggest MDEO can exert inhibitory effects on CRKP, and potential mechanisms of action including inhibition of biofilm formation, damage of cell membrane structure and inhibition of energy metabolism.

Background:It is well known that carbapenem-resistant Klebsiella pneumoniae (CRKP) has become a more problematic public health issue due to its widespread spread worldwide. In China, ST11-type CRKP is the most prevalent CRKP, but ST15-type CRKP, a recently prevalent high-risk clone, has emerged widely throughout China, posing a serious public health risk. Therefore, we conducted an epidemiological of an outbreak of ST15 CRKP of producing CTX-M-15, KPC-2 and SHV-106 in a tertiary hospital in Anhui, China, to Understanding the potential risks of the current STT15 CRKP outbreak.Results:From July 2021 to December 2021, 13 ST15 CRKP isolates were identified by collecting non-repeated clinical multidrug-resistant isolates, with all capsular typing of serotype KL19. All ST15 CRKP isolates were resistant to cephalosporins, carbapenems and quinolones, but were sensitive to amikacin, tigecycline and polymyxin B. In addition, isolates carried blaSHV−106 (100%), blaKPC−2 (69%), blaCTX−M−15 (69%), blaTEM−1B (69%), blaOXA−1 (62%) and blaLAP−2 (8%), as well as iron chelators (iutA, ybt, fyuA, ent, fepA, irp1, irp2, 100%) were detected. In phenotyping experiments, all ST15 CRKP exhibited lower growth rates than NTUH-K2044, and all ST15 CRKP did not exhibit mucoviscositty characteristics. However, in the Galleria mellonella infection model, isolates 21081212, 21081241 and 21091216 were more lethal than the hypervirulent isolates NTUH-K2044. Sequencing results showed that the genetic environment surrounding the genes blaSHV−106, blaKPC−2, blaCTX−M−15, blaOXA−1 and blaTEM−1B were all identical in the ST15 CRKP isolates. Phylogenetic analysis showed that 13 ST15 CRKP isolates were divided into three subgroups, and when placed in global analysis, 10 of them were highly homologous to isolates from Jiangsu, two were highly homologous to isolates from Zhejiang, and one was homologous to an isolate from an unlabelled region.Conclusion:Our research shows that ST15 CRKP, which carries multiple β-lactamases genes and siderophores-encoding genes, may be evolving to hypervirulence and may have spread widely in localised areas. Therefore, environmental surveillance and clinical infection control in hospitals should be strengthened to prevent further spread of ST15 CRKP.

Background: Catheter related blood stream infection (CRBSI) is one of the most serious complications of the central venous catheterization and can lead to severe sepsis, catheter loss, and death. The ethanol lock (EL) is now widely used as a second line therapy and secondary prevention of CRBSI especially in patients with intestinal failure. Objective: The present study’s objective was to evaluate the effectiveness of EL as the primary prevention of CRBSI in pediatric surgical patients. Materials and Methods: The present study was an experimental study that used EL in all pediatric surgical patients with central venous catheter (CVC) hospitalized between February 2020 and January 2021.The EL was done by indwelling the CVC with 70% ethanol for at least four hours per day, then the ethanol was aspirated from the catheter before routine using of the catheter. Data collection included demographics, catheter days, complication of CVC, and EL were collected. Statistical analysis was done using SPSS statistics program. Results: All 13 patients enrolled in the present study had intestinal failure or other gastrointestinal conditions that required a long-term CVC. The results showed no CRBSI in all patients. After using the EL for 1,930 catheter days, the incidence rate of CRBSI was 0 per 1,000 catheter days. The EL group was 1.29 times more likely not to develop CRBSI (RR 1.29, 95% CI 1.10 to 1.52). The authors’ CRBSI rates have declined from 3.84 per 1,000 catheter days in 2019 to 0 per 1,000 catheter days after using EL. One patient had central line removal due to mechanical breakage of the line while returning home. Conclusion: EL prevents CRBSI effectively in pediatric surgical patients especially in tunneled catheter usage. Keywords: Ethanol lock; Catheter related blood stream infection; Central venous catheter

SUMMARYResearch backgroundGiven the known antibacterial properties of royal jelly (RJ), we hypothesize that royal jelly could inhibit priority multidrug-resistant (MDR) bacteria, including different strains of vancomycin-resistant Enterococcus faecium (VRE), methicillin-resistant Staphylococcus aureus (MRSA), carbapenem-resistant Klebsiella pneumoniae (CRKP) and Acinetobacter baumannii (CRAB). We further propose that the antibacterial efficacy of royal jelly may be influenced by its chemical composition and by inter- and intraspecies variability among MDR pathogens.Experimental approachRoyal jelly samples were collected from five beekeepers (RJ1–RJ5) in the Mediterranean and continental regions of Croatia. Chemical profiling was conducted using solid-phase microextraction gas chromatography–mass spectrometry (HS-SPME/GC-MS) and Fourier-transform infrared (FTIR) spectroscopy, together with separate assays to measure antioxidant capacity (ABTS) and quantify the content of bioactive compounds. Antibacterial activity was assessed by agar well diffusion assay and by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against 20 MDR strains of VRE, MRSA, CRKP and CRAB, selected from 85 isolates using repetitive sequence-based PCR (rep-PCR) genotyping. MDR status was confirmed by standard susceptibility testing.Results and conclusionsAll royal jelly samples showed strong antioxidant activity and high amounts of bioactive compounds, with RJ1 consistently exhibiting the highest contents of ABTS, polyphenols, flavonoids and proteins. FTIR analysis revealed variations in carbohydrate and lipid composition among samples, while protein content remained relatively uniform, and indicated the highest mass fractions of sugars, lipids and proteins in RJ1. GC-MS identified octanoic acid (48.09–83.07 %) as the predominant volatile compound, especially abundant in RJ1 and RJ4. Despite some variability in chemical profiles, both chemical composition and antibacterial activity were comparable between samples from the Mediterranean and continental regions. All royal jelly samples inhibited MDR bacteria, suggesting a potential synergistic effect of crude royal jellies, with inhibition zones ranging from 11.8 (CRKP) to 16.8 mm (MRSA). A. baumannii was most susceptible (MIC/MBC=27.2 µg/mL), while E. faecium was the most resistant (MIC=96.6 µg/mL, MBC=126.4 µg/mL). Beyond interspecies differences, pronounced strain-level variability in antibacterial response was also observed.Novelty and scientific contributionThis is the first study to simultaneously evaluate the antibacterial activity of royal jelly against multiple strains of clinically relevant MDR pathogens alongside comprehensive chemical profiling. Importantly, it reveals for the first time that the efficacy of royal jelly varies not only between species but also among strains within the same species, emphasizing the need to consider strain-level differences in future assessments.