BACKGROUND AND OBJECTIVE

The human nasal passages host major human pathogens. Recent research suggests that the microbial communities inhabiting the epithelial surfaces of the nasal passages play a key factor in maintaining a healthy microenvironment by affecting both resistance to pathogens and immunological responses. Colonization of the nasal cavity by different pathogens such as Staphylococcus aureus and Klebsiella aerogenes, is associated with a higher postoperative infection morbidity. Povidone-iodine (PVP-I) as an antiseptic has been proven to display high antibacterial, antiviral, and antifungal properties even at low concentrations, and was shown to be effective in the control of infections to limit their impact and spread. It can be used as a topical antiseptic for skin decontamination and wound management, as a nasal spray, or as a gargle. There are different methods in testing the efficacy of potential antimicrobial suspensions. This study aimed to determine the concentration of PVP-I that is most effective in nasal decolonization using microsuspension test and colorimetric minimum inhibitory concentration (MIC) determination assays, resazurin microtiter assay (REMA), and Dey-Engley (D/E) neutralizer assay. The findings of this study will contribute to knowledge regarding the intended use of PVP-I in microbial control, particularly in bacterial infections.

Several dilutions (2.0%, 1.0%, 0.5%, 0.25%, 0.1% and 0.09%) of commercially bought 10% (10 mg per 100 ml) povidone-iodine were prepared and tested against a standardized inoculum (1x105) of Staphylococcus aureus and Klebsiella aerogenes at different contacttimes (5 seconds, 10 seconds, 30 seconds, 1 minute, and 5 minutes). Microdilution suspension test was performed to determine the log reduction per variable, while REMA and D/E neutralizer assay were used to determine the MIC. A value of greater than or equal to 5 log reduction was considered effective for microdilution suspension test. Estimates of agreement statistics were used to interpret the results of the assay in which the overall percent agreement (OPA), positive percent agreement (PPA), negative percent agreement (NPA), and Cohen’s kappa statistics were calculated.

Povidone-iodine concentration of 0.25% exhibited ?5 log reduction against K. aerogenes at the minimum contact time of 5 seconds. On the other hand,  a slightly higher PVP-I concentration was required to achieve ?5 log reduction for S. aureus at 0.5% concentration and a minimum contact time of 1 minute. There was an observed concordance of the results of REMA and D/E neutralizer as MIC colorimetric indicators, which yielded an overall test percent agreement of 90.30% (95% CI: 84.73–94.36), and a strong level of agreement (? = 0.8, pCONCLUSION

Low povidone-iodine concentrations (i.e., 0.5% against S. aureus and 0.25% against K. aerogenes) were observed to have bactericidal activity of at least 5 log reduction as rapid as the minimum contact time of 5 seconds. Furthermore, D/E and REMA, as colorimetric indicators, had comparable performance (OPA = 90.30%; ? = 0.8, p
Human ; Bacteria ; Povidone-iodine ; Microbial Sensitivity Tests ; Anti-infective Agents, Local ; Enterobacter Aerogenes ; Staphylococcus Aureus

OBJECTIVE: To explore the mechanism of antibiotic delivery system targeting bacterial biofilm with linezolid (LZD) based on ε-poly- L-lysine (ε-PLL) and cyclodextrin (CD) (ε-PLL-CD-LZD), aiming to enhance antibiotic bioavailability, effectively penetrate and disrupt biofilm structures, and thereby improve the treatment of bone and joint infections. METHODS: ε-PLL-CD-LZD was synthesized via chemical methods. The grafting rate of CD was characterized using nuclear magnetic resonance. In vitro biocompatibility was evaluated through live/dead cell staining after co-culturing with mouse embryonic osteoblast precursor cells (MC3T3-E1), human umbilical vein endothelial cells, and mouse embryonic fibroblast cells (3T3-L1). The biofilm-enrichment capacity of ε-PLL-CD-LZD was assessed using Staphylococcus aureus biofilms through enrichment studies. Its biofilm eradication efficacy was investigated via minimum inhibitory concentration (MIC) determination, scanning electron microscopy, and live/dead bacterial staining. A bone and joint infection model in male Sprague-Dawley rats was established to validate the antibacterial effects of ε-PLL-CD-LZD. RESULTS: In ε-PLL-CD-LZD, the average grafting rate of CD reached 9.88%. The cell viability exceeded 90% after co-culturing with three types cells. The strong biofilm enrichment capability was observed with a MIC of 2 mg/L. Scanning electron microscopy observations revealed the effective disruption of biofilm structure, indicating potent biofilm eradication capacity. In vivo rat experiments demonstrated that ε-PLL-CD-LZD significantly reduced bacterial load and infection positivity rate at the lesion site ( P<0.05). CONCLUSION The ε-PLL-CD antibiotic delivery system provides a treatment strategy for bone and joint infections with high clinical translational significance. By effectively enhancing antibiotic bioavailability, penetrating, and disrupting biofilms, it demonstrated significant anti-infection effects in animal models.
Biofilms/drug effects* ; Animals ; Anti-Bacterial Agents/pharmacology* ; Polylysine/chemistry* ; Cyclodextrins/administration & dosage* ; Humans ; Linezolid/pharmacology* ; Staphylococcus aureus/physiology* ; Rats, Sprague-Dawley ; Mice ; Rats ; Male ; Drug Delivery Systems ; Staphylococcal Infections/drug therapy* ; Microbial Sensitivity Tests ; Human Umbilical Vein Endothelial Cells ; Osteoblasts/cytology*

OBJECTIVES: To investigate the clinical characteristics and drug resistance profile of invasive non-typhoidal Salmonella (NTS) enteritis in children in Chengdu, China, providing a reference for rational drug use and empirical treatment in clinical practice. METHODS: A retrospective analysis was conducted on the clinical data of 130 children with invasive bacterial enteritis due to NTS identified by fecal bacterial culture and the results of drug sensitivity tests for NTS in Chengdu from January 2022 to December 2023. RESULTS: NTS infections were mainly observed from April to September (113 cases, 86.9%), with a peak in August (36 cases, 27.7%). Children aged <36 months accounted for 86.2% (112/130) of all cases, and the main symptoms were diarrhea (130 cases, 100%), fever (123 cases, 94.6%), and hematochezia (112 cases, 86.2%). The 130 NTS isolates exhibited a sensitivity rate of 64.6% to ceftriaxone and 63.8% to cefotaxime, and a sensitivity rate of >90.0% to piperacillin-tazobactam and nitrofurantoin (nitrofurans). The detection rate of multidrug-resistant strains was 48.5% (63/130), and the clinical efficacy of third-generation cephalosporins used in 38 patients (29.2%) was inconsistent with the results of drug sensitivity tests. CONCLUSIONS The peak of invasive NTS enteritis in children aged 0-6 years occurs in August in the Chengdu area, with a relatively high incidence rate in children aged <36 months. The situation of drug resistance is severe for NTS, and piperacillin-tazobactam may be an effective option for treating multidrug-resistant NTS infections in children, while nitrofuran antibiotics might be used to treat such infections.
Humans ; Infant ; Child, Preschool ; Enteritis/microbiology* ; Retrospective Studies ; Male ; Salmonella Infections/microbiology* ; Female ; Child ; Salmonella/drug effects* ; Infant, Newborn ; Microbial Sensitivity Tests ; Anti-Bacterial Agents/therapeutic use*

OBJECTIVE: To investigate the risk factors, clinical characteristics, and bacterial resistance of bloodstream infections caused by Streptococcus mitis in children with hematological disease, so as to provide a reference for infection control. METHODS: The clinical information and laboratory findings of pediatric patients complicated with blood cultures positive for Streptococcus mitis from January 2018 to December 2020 in the Institute of Hematology & Blood Diseases Hospital were searched and collected. The clinical characteristics, susceptibility factors, and antibiotic resistance of the children were retrospectively analyzed. RESULTS: Data analysis from 2018 to 2020 showed that the proportion of Streptococcus mitis isolated from bloodstream infections in children (≤14 years old) with hematological diseases was the highest (19.91%) and significantly higher than other bacteria, accounting for 38.64% of Gram-positive cocci, and presented as an increasing trend year by year. A total of 427 children tested positive blood cultures, including 85 children with bloodstream infections caused by Streptococcus mitis who tested after fever. Most children experienced a recurrent high fever in the early and middle stages (≤6 d) of neutropenia and persistent fever for more than 3 days. After adjusting the antibiotics according to the preliminary drug susceptibility results, the body temperature of most children (63.5%) returned to normal within 4 days. The 85 children were mainly diagnosed with acute myeloid leukemia (AML), accounting for 84.7%. The proportion of children in the neutropenia stage was 97.7%. The incidence of oral mucosal damage, lung infection, and gastrointestinal injury symptoms was 40%, 31.8%, and 27.1%, respectively. The ratio of elevated C-reactive protein (CRP) and procalcitonin was 65.9% and 9.4%, respectively. All isolated strains of Streptococcus mitis were not resistant to vancomycin and linezolid, and the resistance rate to penicillin, cefotaxime, levofloxacin, and quinupristin-dalfopristin was 10.6%, 8.2%, 9.4%, and 14.1%, respectively. None of children died due to bloodstream infection caused by Streptococcus mitis. CONCLUSION The infection rate of Streptococcus mitis is increasing year by year in children with hematological diseases, especially in children with AML. Among them, neutropenia and oral mucosal damage after chemotherapy are high-risk infection factors. The common clinical symptoms include persistent high fever, oral mucosal damage, and elevated CRP. Penicillin and cephalosporins have good sensitivity. Linezolid, as a highly sensitive antibiotic, can effectively control infection and shorten the course of disease.
Humans ; Child ; Streptococcal Infections/microbiology* ; Retrospective Studies ; Hematologic Diseases/complications* ; Streptococcus mitis ; Drug Resistance, Bacterial ; Risk Factors ; Microbial Sensitivity Tests ; Anti-Bacterial Agents ; Female ; Male ; Bacteremia/microbiology* ; Child, Preschool ; Adolescent

OBJECTIVE: To map the potent antifungal properties of the medicinal plant Vitex negundo, in vitro and in silico studies were performed to decipher the pharmacokinetics and ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) properties of their phytoconstituents. METHODS: With the PASS (Prediction of Activity Spectra for Substances) prediction tool, many parameters of V. negundo phenolics were examined, including drug-likeness, bioavailability, antifungal activity, and anti-biofilm activity. Moreover, ADMET parameters were also determined. RESULTS: Eighteen phenolic compounds from V. negundo with significant antifungal activity against Candida species (human fungal pathogens) were detected. The antioxidant activity, inhibition percentage, and minimum inhibitory concentration value of V. negundo phenolic extracts indicate it as an effective antifungal agent for the treatment of candidiasis caused by the fungal pathogen Candida albicans. Many phenolic compounds showed a significantly high efficiency against Candida's planktonic cells and biofilm condition. CONCLUSIONS The phenolics fraction of V. negundo has potent antifungal activities, however, some more pre-clinical studies are a matter of future research to further investigate V. negundo phenolic compound as a potential new antifungal arsenal.
Candida albicans/physiology* ; Vitex/chemistry* ; Antifungal Agents/chemistry* ; Microbial Sensitivity Tests ; Biofilms/drug effects* ; Phenols/pharmacokinetics* ; Plant Extracts/chemistry* ; Antioxidants/pharmacology* ; Phytochemicals/pharmacology* ; Humans

OBJECTIVES: To explore the efficacy of low-intensity pulsed ultrasound (LIPUS) combined with nystatin for treatment of vaginal Candida albicans biofilm infection. METHODS: In vitro cultured Candida albicans biofilm were treated with LIPUS, nystatin, or both, and the minimum inhibitory concentration (MIC) of nystatin was determined. Crystal violet staining, confocal laser microscopy (CLSM) and scanning electron microscopy were used to quantify the biofilm and observe the activity and morphological changes of the biofilms; DCFH-DA was used to detect the changes in reactive oxygen species (ROS). Twenty female New Zealand White rabbits with vaginal inoculation of Candida albicans biofilm were randomized into 4 groups for treatment with normal saline, LIPUS, nystatin, or both LIPUS and nystatin. The changes in vulvar symptoms of the rabbits were observed, and the histopathological and ultrastructural changes of the vagina before and after treatment were observed using HE staining and transmission electron microscopy. RESULTS: In the combined treatment group, the MIC₅₀ and MIC₈₀ of nystatin in Candida albicans biofilms were both reduced by 50% compared with those in nystatin group, and the biofilm clearance rate increased by 26% and 68% compared with nystatin and LIPUS groups, respectively. Compared with nystatin and LIPUS treatment alone, the combined treatment produced stronger effects for inhibiting biofilm activity, causing structural disruption and promoting ROS production. In the rabbit models, the combined treatment more effectively improved vulvar symptoms and inflammatory infiltration, reduced residual vaginal hyphae/strains, and improved ultrastructure of the vaginal epithelium than LIPUS and nystatin treatment alone. CONCLUSIONS LIPUS combined with nystatin produces a significant synergistic antifungal effect against Candida albicans biofilm both in vitro and in vivo.
Animals ; Rabbits ; Female ; Biofilms/drug effects* ; Candida albicans/physiology* ; Nystatin/therapeutic use* ; Candidiasis, Vulvovaginal/microbiology* ; Ultrasonic Waves ; Antifungal Agents/therapeutic use* ; Vagina/microbiology* ; Ultrasonic Therapy ; Microbial Sensitivity Tests ; Combined Modality Therapy

In this study, we employed a combination of genome mining and heteronuclear single quantum coherence (HSQC)-based small molecule accurate recognition technology (SMART) technology to search for fernane-type triterpenoids. Initially, potential endophytic fungi were identified through genome mining. Subsequently, fine fractions containing various fernane-type triterpenoids were selected using HSQC data collection and SMART prediction. These triterpenoids were then obtained through targeted isolation and identification. Finally, their antifungal activity was evaluated. As a result, three fernane-type triterpenoids, including two novel compounds, along with two new sesquiterpenes and four known compounds were isolated from one potential strain, Diaporthe discoidispora. Their structures were elucidated through analysis of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) and nuclear magnetic resonance (NMR) spectroscopic data. The absolute configurations were determined using single-crystal X-ray diffraction analysis and electron capture detector (ECD) analysis. Compound 3 exhibited moderate antifungal activity against Candida albicans CMCC 98001 and Aspergillus niger.
Triterpenes/isolation & purification* ; Antifungal Agents/isolation & purification* ; Molecular Structure ; Candida albicans/drug effects* ; Ascomycota/genetics* ; Magnetic Resonance Spectroscopy ; Aspergillus niger/drug effects* ; Genome, Fungal ; Microbial Sensitivity Tests

Given the increasing concern regarding antibacterial resistance, the antimicrobial properties of naphthoquinones have recently attracted significant attention. While 1,4-naphthoquinone and its derivatives have been extensively studied, the antibacterial properties of 5,8-dihydroxy-1,4-naphthoquinone derivatives remain relatively unexplored. This study presents a comprehensive in vitro and in vivo analysis of the antibacterial activity of 35 naturally sourced and chemically synthesized derivatives of 5,8-dihydroxy-1,4-naphthoquinone. Kirby-Bauer antibiotic testing identified three compounds with activity against methicillin-resistant Staphylococcus aureus (MRSA), with one compound (PNP-02) demonstrating activity comparable to vancomycin in minimum inhibitory concentration, minimum bactericidal concentration (MBC), and time-kill assays. Microscopic and biochemical analyses revealed that PNP-02 adversely affects the cell wall and cell membrane of MRSA. Mechanistic investigations, including proteomic sequencing analyses, Western blotting, and RT-qPCR assays, indicated that PNP-02 compromises cell membrane integrity by inhibiting arginine biosynthesis and pyrimidine metabolism pathways, thereby increasing membrane permeability and inducing bacterial death. In an in vivo mouse model of skin wound healing, PNP-02 exhibited antibacterial efficacy similar to vancomycin. The compound demonstrated low toxicity to cultured human cells and in hemolysis assays and remained stable during serum incubation. These findings suggest that PNP-02 possesses promising bioactivity against MRSA and represents a potential novel antibacterial agent.
Methicillin-Resistant Staphylococcus aureus/genetics* ; Anti-Bacterial Agents/chemistry* ; Naphthoquinones/administration & dosage* ; Animals ; Microbial Sensitivity Tests ; Mice ; Humans ; Staphylococcal Infections/microbiology* ; Molecular Structure

Artemisia argyi (A. argyi), a plant with a longstanding history as a raw material for traditional medicine and functional diets in Asia, has been used traditionally to bathe and soak feet for its disinfectant and itch-relieving properties. Despite its widespread use, scientific evidence validating the antifungal efficacy of A. argyi water extract (AAWE) against dermatophytes, particularly Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum gypseum, remains limited. This study aimed to substantiate the scientific basis of the folkloric use of A. argyi by evaluating the antifungal effects and the underlying molecular mechanisms of its active subfraction against dermatophytes. The results indicated that AAWE exhibited excellent antifungal effects against the three aforementioned dermatophyte species. The subfraction AAWE6, isolated using D101 macroporous resin, emerged as the most potent subfraction. The minimum inhibitory concentrations (MICs) of AAWE6 against T. rubrum, M. gypseum, and T. mentagrophytes were 312.5, 312.5, and 625 μg·mL^-1, respectively. Transmission electron microscopy (TEM) results and assays of enzymes linked to cell wall integrity and cell membrane function indicated that AAWE6 could penetrate the external protective barrier of T. rubrum, creating breaches ("small holes"), and disrupt the internal mitochondrial structure ("granary"). Furthermore, transcriptome data, quantitative real-time PCR (RT-qPCR), and biochemical assays corroborated the severe disruption of mitochondrial function, evidenced by inhibited tricarboxylic acid (TCA) cycle and energy metabolism. Additionally, chemical characterization and molecular docking analyses identified flavonoids, primarily eupatilin (131.16 ± 4.52 mg·g^-1) and jaceosidin (4.17 ± 0.18 mg·g^-1), as the active components of AAWE6. In conclusion, the subfraction AAWE6 from A. argyi exerts antifungal effects against dermatophytes by disrupting mitochondrial morphology and function. This research validates the traditional use of A. argyi and provides scientific support for its anti-dermatophytic applications, as recognized in the Chinese patent (No. ZL202111161301.9).
Antifungal Agents/chemistry* ; Arthrodermataceae ; Artemisia/chemistry* ; Molecular Docking Simulation ; Mitochondria ; Microbial Sensitivity Tests

OBJECTIVES: Bloodstream infections in emergency patients have a high incidence, severe disease progression, and rapid deterioration. Early administration of appropriate antimicrobial agents is crucial for improving patient outcomes. This study aims to investigate the incidence, pathogen distribution, and antimicrobial resistance patterns of bloodstream infections in emergency patients, providing a reference for rational antibiotic use in clinical practice. METHODS: Medical records of patients diagnosed with bloodstream infections in the emergency department of a hospital in Hunan Province between January 2018 and October 2022 were retrospectively collected. Clinical characteristics of bloodstream infection patients were analyzed, and the distribution trends and antimicrobial susceptibility of clinical isolates were examined. RESULTS: During the study period, 2 215 blood culture samples were submitted from the emergency department, with a positivity rate of 13.27%. After excluding eight cases with missing data or suspected contamination, 286 patients with bloodstream infections were included, with community-acquired infections accounting for the majority (85.66%). The most common primary infection site was the urinary tract (24.48%), followed by respiratory tract infections (20.28%) and biliary and intra-abdominal infections (17.13%). The 30-day mortality rate of bloodstream infections was 16.08%. A total of 286 pathogens were isolated, including 181 (63.29%) Gram-negative bacteria, primarily Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa; 101 (35.31%) Gram-positive bacteria, mainly Staphylococcus aureus, Staphylococcus epidermidis, and Streptococcus pneumoniae; and only 4 (1.40%) fungal isolates. Antimicrobial susceptibility testing showed that the key Enterobacteriaceae strains exhibited resistance rates of 2.4% to carbapenems, 16.3% to piperacillin sodium and tazobactam sodium, and 15.3% to ceftazidime, with no detected resistance to tigecycline or polymyxins. The main non-fermentative bacteria showed resistance rates of 29.6% to piperacillin sodium and tazobactam sodium, 13.3% to cefoperazone sodium and sulbactam sodium, and 27.1% to quinolones. Among Gram-negative bacteria, multidrug-resistant strains accounted for 40.9% (74/181), with carbapenem-resistant Escherichia coli and Klebsiella pneumoniae detected in 5.4% (5/92) and 13.6% (6/44) of cases, respectively. No carbapenem-resistant Pseudomonas aeruginosa was identified. Among Gram-positive bacteria, resistance rates to penicillin G, rifampicin, and cefoxitin were 74.7%, 4.2%, and 50%, respectively, with only 3 cases of resistant to glycopeptide antibiotics. CONCLUSIONS Bloodstream infections in emergency patients are predominantly community-acquired, with Gram-negative bacteria being the most common pathogens. The isolated pathogens exhibited relatively low resistance rates to commonly used clinical antibiotics.
Retrospective Studies ; Emergency Service, Hospital/statistics & numerical data* ; Drug Resistance, Bacterial ; Anti-Bacterial Agents/therapeutic use* ; Incidence ; Microbial Sensitivity Tests/statistics & numerical data* ; Bacteremia/microbiology* ; Community-Acquired Infections/microbiology* ; Gram-Negative Bacteria/isolation & purification* ; Blood Culture/statistics & numerical data* ; Humans ; Male ; Female ; Adolescent ; Young Adult ; Adult ; Middle Aged ; Aged ; Aged, 80 and over ; China/epidemiology*