Staphylococcus epidermidis--the 'accidental' pathogen

Extracellular DNA and polysaccharide intercellular adhesin protect Staphylococcus epidermidis biofilms from phagocytosis by polymorphonuclear neutrophils

Staphylococcus epidermidis is the leading cause of implant-associated infections, where it forms biofilms that are highly effective at evading the immune system. Here we investigate to what extent the biofilm extracellular matrix components extracellular DNA (eDNA) and polysaccharide intercellular adhesin (PIA) protect S. epidermidis from phagocytosis by polymorphonuclear neutrophils (PMN). We visualised phagocytosis using time-lapse confocal laser scanning microscopy of PMN interacting with planktonic S. epidermidis and 24 h old biofilms formed by the wildtype strain or mutant strains lacking either eDNA or PIA. We also compared phagocytosis of 24 h vs. 6 h old biofilms. PMN easily moved around and phagocytised S. epidermidis that were adhered to a surface from a planktonic culture. In contrast, PMN quickly became immobilised when interacting with biofilms. Very few PMN were able to phagocytise young (6 h) and mature (24 h) biofilms, suggesting that the accumulation of matrix components quickly provides a protective effect. Biofilms lacking either eDNA or PIA were much less dense, and many more PMN were able to phagocytise bacteria in these biofilms. Our findings suggest that both eDNA and PIA contribute to the ability of S. epidermidis biofilms to resist phagocytosis.

Biomimetic hyaluronic acid-stabilized zinc oxide nanoparticles in acne treatment: A preclinical and clinical approach

Acne vulgaris is a common chronic inflammatory skin condition, often caused by C. acnes infection. While ZnO has shown promise as an antibacterial agent in acne treatment, concerns over toxicity and non-selective bacterial killing remain. In this study we developed a hyaluronic acid-stabilized nano‑zinc oxide (HA-ZnO) formulation aimed at enhancing the therapeutic efficacy and safety of ZnO for acne treatment. HA-ZnO was synthesized through biomimetic mineralization. HA-ZnO targeted acne-prone areas, especially sebaceous glands, without skin penetration. HA-ZnO demonstrated selective antibacterial activity against C. acnes, exhibiting a killing efficacy more than 16 times greater than that against S. epidermidis. The HA coating also improved ZnO's stability in acidic conditions, mitigating potential toxicity and side effects. Additionally, the sustained release of Zn2+ promoted cell proliferation and migration, reducing sebum secretion, and exerting anti-inflammatory effects, supporting scar-free acne repair and preventing recurrence. In preclinical models, HA-ZnO outperformed erythromycin ointment in treating acne, with no toxicity observed in zebrafish and HET-CAM. A clinical trial further confirmed its efficacy in reducing acne lesions and redness, with high safety. These results highlight HA-ZnO as a promising therapeutic strategy for acne, combining potent antibacterial and skin-repairing effects with enhanced safety.

Early fibrin biofilm development in cardiovascular infections

The single most common microbe causing cardiovascular infections is Staphylococcus aureus (S. aureus). S. aureus produces coagulase that converts fibrinogen to fibrin, which is incorporated into biofilms. This process aids in adherence to intravascular structures, defense against the host immune system, and resistance to antimicrobial treatment. Despite its significance, fibrin formation in S. aureus biofilms remains poorly understood. Therefore, this study aimed to elucidate the early development of cardiovascular biofilms. Clinically isolated coagulase-positive S. aureus and coagulase-negative Staphylococcus lugdunensis (S. lugdunensis) from patients with cardiovascular infections, and a coagulase mutant S. aureus Δcoa, were grown in tryptic soy broth (TSB), Iscove's Modified Dulbecco's Medium (IMDM), and pooled human plasma, with or without porcine heart valves. Bacterial growth, metabolic activity, and bacterial fibrinogen utilization were measured over 24 h at 37 °C. Time-lapse confocal microscopy was used to visualize and track biofilm development. S. aureus exhibited more growth in TSB and human plasma than S. lugdunensis and S. aureus Δcoa, but showed similar growth in IMDM after 24 h. Peak metabolic activity for all isolates was highest in TSB and lowest in human plasma. The presence of porcine valves caused strain-dependent alterations in time to peak metabolic activity. Confocal imaging revealed fibrin-based biofilm development exclusively in the coagulase-producing S. aureus strains. Between 2 and 6 h of biofilm development, 74.9 % (p = 0.034) of the fibrinogen from the medium was converted to fibrin. Variations in fibrin network porosity and density were observed among different coagulase-producing S. aureus strains. Fibrin formation is mediated by S. aureus coagulase and first strands occurred within 3 h for clinical strains after exposure to human plasma. This study stresses the importance of experimental design given the bacterial changes due to different media and substrates and provides insights into the early pathogenesis of S. aureus cardiovascular biofilms.

Genome-scale metabolic model of Staphylococcus epidermidis ATCC 12228 matches in vitro conditions

Staphylococcus epidermidis, a commensal bacterium inhabiting collagen-rich areas like human skin, has gained significance due to its probiotic potential in the nasal microbiome and as a leading cause of nosocomial infections. While infrequently leading to severe illnesses, S. epidermidis exerts a significant influence, particularly in its close association with implant-related infections and its role as a classic opportunistic biofilm former. Understanding its opportunistic nature is crucial for developing novel therapeutic strategies, addressing both its beneficial and pathogenic aspects, and alleviating the burdens it imposes on patients and healthcare systems. Here, we employ genome-scale metabolic modeling as a powerful tool to elucidate the metabolic capabilities of S. epidermidis. We created a comprehensive computational resource for understanding the organism's growth conditions within diverse habitats by reconstructing and analyzing a manually curated and experimentally validated metabolic model. The final network, iSep23, incorporates 1,415 reactions, 1,051 metabolites, and 705 genes, adhering to established community standards and modeling guidelines. Benchmarking with the Metabolic Model Testing suite yields a high score, indicating the model's remarkable semantic quality. Following the findable, accessible, interoperable, and reusable (FAIR) data principles, iSep23 becomes a valuable and publicly accessible asset for subsequent studies. Growth simulations and carbon source utilization predictions align with experimental results, showcasing the model's predictive power. Ultimately, this work provides a robust foundation for future research aimed at both exploiting the probiotic potential and mitigating the pathogenic risks posed by S. epidermidis.

IMPORTANCE

Staphylococcus epidermidis, a bacterium commonly found on human skin, has shown probiotic effects in the nasal microbiome and is a notable causative agent of hospital-acquired infections. While these infections are typically non-life-threatening, their economic impact is considerable, with annual costs reaching billions of dollars in the United States. To better understand its opportunistic nature, we employed genome-scale metabolic modeling to construct a detailed network of S. epidermidis's metabolic capabilities. This model, comprising over a thousand reactions, metabolites, and genes, adheres to established standards and demonstrates solid benchmarking performance. Following the findable, accessible, interoperable, and reusable (FAIR) data principles, the model provides a valuable resource for future research. Growth simulations and predictions closely match experimental data, underscoring the model's predictive accuracy. Overall, this work lays a solid foundation for future studies aimed at leveraging the beneficial properties of S. epidermidis while mitigating its pathogenic potential.

Identification of bacteria on Thai banknotes and coins using MALDI-TOF mass spectrometry and their phenotypic antimicrobial susceptibility profiles

Background

The existence and transmission of pathogenic and antibiotic-resistant bacteria through currency banknotes and coins poses a global public health risk. Banknotes and coins are handled by people in everyday life and have been identified as a universal medium for potentially microbial contamination.

Methods

To ascertain existence of medically important bacteria, a total of 300 samples including 150 banknotes and 150 coins were randomly collected at onsite retail fresh meat stores, i.e., pork and chicken, fish, and seafood stores, from nineteen fresh markets distributed across Bangkok, Thailand. An individual banknote or coin was entirely swabbed, and bacterial culture was carried out using tryptic soy agar (TSA), sheep blood agar (SBA) and MacConkey agar (Mac). A colony count was performed and bacterial species identification was conducted using matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry. Phenotypic antimicrobial susceptibility testing was carried out using the Kirby-Bauer disc diffusion methods.

Results

The results demonstrated that the bacterial contamination rate was higher on banknotes than on coins (93.33% vs. 30.00%) in all three store types. A substantial number of colonies of >3,000 colony forming units (CFU) was predominantly found in banknotes (70.00%), especially from fish store (83.3%); meanwhile, <1,000 CFU was observed in coin sample (76.67%). MALDI-TOF mass spectrometry could identify 107 bacterial species, most of them were Staphylococcus kloosii (14.02%, 15/107), Staphylococcus saprophyticus (12.15%, 13/107), and Macrococcus caseolyticus (8.41%, 9/107). The prevalence based on genera were Staphylococcus (36.45%, 39/107), Acinetobacter (20.56%, 22/107), and Macrococcus (10.28%, 11/107). Almost all Staphylococcus isolates had low susceptibility to penicillin (21%). Notably, Staphylococcus arlettae, Staphylococcus haemolyticus and M. caseolyticus were multidrug-resistant (MDR). It is notable that none of the staphylococci and macrococci isolates exhibited inducible clindamycin resistance (D-test negative). Escherichia coli and Pseudomonas putida isolates were carbapenem-resistant, and Acinetobacter baumannii isolates were MDR with showing carbapenem resistance.

Conclusion

Our data demonstrated a high prevalence of medically important bacteria presented on Thai currency, which may pose a potential risk to human health and food safety. Food vendors and consumers should be educated about the possible cross-contamination of bacteria between the environment, food item, and currency.

Antifouling Efficacy on S. epidermidis of Nano-Au Surfaces Functionalized with Polyethylene Glycol (PEG)-Tethered Antimicrobial Peptides

Cationic antimicrobial peptides (cAMPs) kill bacteria in solution by membrane lysis; however, translating cAMPs into a covalently attached antibacterial coating is challenging since it remains unclear how the specifics of the conjugation impact the antifouling efficacy. Furthermore, studies have typically assessed cAMP coatings with a high and homogeneous surface coverage, although this may be difficult to implement in practice of the materials commonly used in medicine. Herein, we investigate the antifouling efficacy of fractional surface coatings made from poly(ethylene glycol) (PEG)-tethered cAMPs presented on gold nanoparticles (AuNPs) deposited onto surfaces. For all tested cAMPs, the antifouling efficacy increases exponentially with the 2D surface coverage of the coating. However, although the cAMPs have a similar primary sequence and display similar potency against Staphylococcus epidermidis in solution, the cyclic peptide is much more potent after tethering to the AuNPs than the linear counterparts. The attachment of the cyclic cAMPs also led to an unexpected shrinkage of the modified PEG-brush by more than 50%, indicating a restricted mobility of the tethering PEG chains. The shrinkage increased the closeness of the peptide on the AuNP and may thus enable cooperative actions of the grafted cAMPs such as the formation of nanosized peptide clusters that were previously found to enhance cAMP potency in solution. These findings pave the way for antibacterial coatings that cover only a subfraction of a material while remaining active in a clinical setting.

Prevalence and antimicrobial resistance of bacteria isolated from urine samples of cats with urinary tract infections in Illinois, United States of America

Information on antimicrobial resistance patterns of urinary pathogens of cats can aid veterinarians in their antimicrobial prescription choices. We assessed the prevalence and antimicrobial resistance of bacteria isolated from urine samples of cats with urinary tract infections (UTIs) submitted to a veterinary diagnostic laboratory in Illinois between 2020 and 2022. The laboratory received 2026 urine samples during the study period, of which 606 (29.97%) showed bacterial growth, and from these samples, 883 bacterial strains were recovered. The most common gram-positive bacterial species included Enterococcus faecalis (n = 123), Staphylococcus felis (n = 50), and Staphylococcus pseudintermedius (n = 28), while the most common gram-negative bacteria included Escherichia coli (n = 322) and Proteus mirabilis (n = 18). Among the gram-positive isolates, none of the Enterococcus faecalis isolates showed resistance to amoxicillin-clavulanic acid and ampicillin. In addition, Staphylococcus felis isolates showed low resistance to ampicillin (7.32%), enrofloxacin (4.88%), and amoxicillin-clavulanic acid (4.88%). Among gram-negative bacteria, E. coli isolates showed a high resistance to ampicillin (30.64%), and a moderate resistance to amoxicillin-clavulanic acid (11.78%) and cefovecin (11.11%), antibiotics considered as first-line choices to treat UTIs in cats. Compared to 2020, the rate of E. coli isolates resistant to amoxicillin-clavulanic acid was lower in 2022 (IRR: 0.42; 95%; CI: 0.18-0.99). This study provides antibiograms of common feline urinary pathogens in Illinois that could aid veterinarians in their empirical UTI therapy choices. Requesting an antimicrobial susceptibility test when starting an empirical treatment could be beneficial to guide altered therapy to secure treatment success if the causative pathogens are resistant to the empirical antimicrobial choices.

D-alanylation of lipoteichoic acids inhibitor provides anti-virulence and anti-resistance effects against methicillin-resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) is an emerging multidrug-resistant pathogen responsible for numerous healthcare-associated infections. Most of them are resistant to all classes of antibiotics and thus lead to therapeutic impasse. For this reason, identifying new targets and characterizing new drugs are essential. We recently showed that methicillin-resistant Staphylococcus aureus strains deficient in D-alanylation of teichoic acids (TAs) lost resistance to various β-lactams. Here we explore if D-alanylation of TAs might be a druggable target to overcome β-lactam resistance of MRSE using a competitive DltA inhibitor. The binding affinity of a DltA inhibitor with the purified DltA protein was monitored by determining the half maximal inhibitory concentration (IC50). The efficiency of D-alanylation inhibition was determined by quantifying the ester-linked D-alanine content of purified TAs. Minimal inhibition concentrations (MICs) and bactericidal effects of several β-lactams were monitored in the absence or presence of the inhibitor against a panel of clinical MRSE isolates. Finally, the ability of inhibition of D-alanylation (i) to rescue MRSE-infected larvae of Galleria mellonella and (ii) to prevent or eradicate S. epidermidis biofilms was evaluated. The DltA inhibitor showed IC50 in the low µM range, drastically reduced the D-alanine esters content of TAs and re-sensitized MRSE to β-lactams. The most effective treatment was the DltA inhibitor/imipenem combination. Finally, inhibition of D-alanylation significantly reduced the virulence of MRSE in the G. mellonella infection model and strongly reduced the ability of S. epidermidis to form biofilms. All together, our results show the promising nature of the D-alanylation of TAs as a therapeutic target to fight against MRSE infections.

Pneumolysin-responsive liposomal platform for selective treatment of Streptococcus pneumoniae

The bacterium Streptococcus pneumoniae has become a leading cause of meningitis, sepsis, and bacterial pneumonia worldwide, with increased prevalence of antibiotic-resistant serotypes serving to exacerbate the issue. The main factor responsible for colonization and immune response escape in pneumococcal infections is the secreted molecule pneumolysin, which is a subset within a family of related toxins that form transmembrane pores in biological membranes through cholesterol recognition and binding. The conserved activity and structure of pneumolysin between all observed S. pneumoniae serotypes, along with its requirement for pathogenicity, has made this molecule an attractive target for vaccination, diagnostic, and sequestration platforms, but not yet as a facilitative agent for therapeutic treatment. Consequently, the present work aimed to examine the impact of liposomal cholesterol content for pneumolysin-induced release of the encapsulated antimicrobial peptide nisin. It was determined that a cholesterol content above 45 mol% was necessary to facilitate interactions with both purified pneumolysin toxin and S. pneumoniae culture, demonstrated through enhanced nisin release and a reduction in hemolytic rates upon exposure of the toxin with cholesterol-rich vesicles. Antibacterial testing highlighted the ability of the developed platform to elicit a potent and specific bactericidal response in vitro against cultured S. pneumoniae when compared to a control strain, Staphylococcus epidermidis. It further improved viability of a fibroblast cell line upon S. pneumoniae challenge, outperforming free nisin via the synergistic impact of simultaneous bacterial clearance and pneumolysin neutralization. These findings collectively indicate that cholesterol-rich liposomes hold promise as a selective treatment platform against pneumococcal infections.

Worker risk from ultrasonicator aerosolization in medical device reprocessing: a particulate and bio-burden approach

BACKGROUND

Reprocessing reusable medical devices and surgical instruments is vital for ensuring safe health care in hospitals. Medical device reprocessing departments (MDRDs) handle the cleaning, disinfection and sterilization of these instruments. While previous research has examined bioburden on surfaces and associated patient health risks, there is limited focus on occupational hazards for MDRD workers.

AIM

To investigate the potential bioaerosol exposure and particle concentrations generated by ultrasonic sterilizing water baths within the MDRD at Mount Sinai Hospital, Toronto, Canada.

METHODS

Bioaerosol sampling was conducted using Andersen-style samplers for bacterial and fungal cultures. Particle sampling was measured using optical particle samplers.

RESULTS

The majority of bioaerosols were composed of low-risk skin microflora and waterborne bacteria, predominantly Micrococcus luteus and Staphylococcus spp. However, potentially harmful bacteria such as Citrobacter spp. and Acinetobacter spp. were detected. Fungal genera identified included Aspergillus, Cladosporium and Penicillium.

CONCLUSIONS

Although the overall aerosol generation from ultrasonic cleaning appeared minimal, this study highlights the importance of appropriate personal protective equipment, and suggests the need for further research on ventilation and additional aerosol sources in MDRDs.

Development of a Novel Pan-Species Multi-Epitope Vaccine (PS-MEV) Targeting Nine Staphylococcus Species to Combat Antibiotic Resistance

The increasing prevalence of antibiotic-resistant Staphylococcus species, including methicillin-resistant strains, calls for innovative approaches like a pan-species multi-epitope vaccine (PS-MEV). In this study, Sortase A (SrtA) was selected as the target protein due to its conserved role in Staphylococcus pathogenesis, and the MEV was designed to target nine Staphylococcus species. After stringent filtration of epitopes to ensure antigenicity, non-toxicity, and non-allergenicity, structural models of the MEV construct were generated using I-TASSER, AlphaFold, and RoseTTAFold. Docking analyses confirmed strong binding interactions between the MEV and TLR-3, with the AlphaFold model exhibiting the lowest binding energy of - 1284.1 kcal/mol and a center energy of - 1066.5 kcal/mol. The I-TASSER and RoseTTAFold models showed slightly higher binding energies, with lowest binding energies of - 938.5 kcal/mol and - 950.9 kcal/mol, respectively, and center energies of - 842.2 kcal/mol and - 825.4 kcal/mol. These values demonstrate consistent receptor binding across the models. Molecular dynamics (MD) simulations confirmed the stability of the interactions with the immune receptor, and immune simulations showed notable cytokine peaks, memory cell production, and a sustained T-cell response, indicating the potential for long-lasting immunity. Physicochemical profiling indicated that the vaccine construct is stable, moderately thermostable, and hydrophilic, which can enhance bioavailability and immunogenic effectiveness. This pan-species MEV presents a promising avenue in Staphylococcus vaccine development, with implications for broader applications in combating antibiotic-resistant pathogens.

Mangrove consortium resistant to the emerging contaminant DEHP: Composition, diversity, and ecological function of bacteria

The continuous use of Di(2-ethylhexyl) phthalate (DEHP) in plastic products turns it into a ubiquitous contaminant in the environment. However, DEHP can cause harm to human beings, wildlife, and ecosystems due to its estrogenicity and toxicity. Thus, finding an efficient approach to removing this contaminant from the environment is crucial. The present study aimed to prospect and characterize a bacterial consortium (MP001) isolated from a neotropical mangrove for DEHP bioremediation. A laboratory experiment was performed with environmentally relevant DEHP concentrations (0.05, 0.09, 0.19, 0.38, 0.75, 1.50, 3.00, and 6.00 mg L-1) to determine the consortium resistance to this contaminant and high-throughput sequencing was accomplished to assess the bacterial composition, diversity, and potential ecological function of consortium MP001. The consortium MP001 presented a significant biomass increase throughout short-term incubations with increasing concentrations of DEHP (GLMs, p< 0.001). MP001 was constituted by Paraclostridium sp. (78.99%) and Bacillus sp. (10.73%). After 48 h of consortia exposure to DEHP, the bacterial population changed to Paraclostridium (50.00%), Staphylococcus sp. (12.72%), Staphylococcus epidermidis (10.40%) and Bacillus sp. (17.63%). In the negative control, the bacteria community was composed of Paraclostridium sp. (54.02%), Pseudomonas stutzeri (19.44%), and Staphylococcus sp. (11.97%). The alpha diversity of the MP001 consortium was not significant (Kruskall-Wallis; p > 0.05), and no significant difference was found between the DEHP treatment and the negative control. Furthermore, the potential ecological function found in the consortium MP001 with higher potential for application in bioremediation purposes was fermentation. The results found in this study highlight the potential of a bacterial consortium to be used in the bioremediation of DEHP-contaminated aquatic environments.

Evaluating the Effect of an Essential Oil Blend on the Growth and Fitness of Gram-Positive and Gram-Negative Bacteria

The increasing prevalence of antibiotic-resistant bacteria has necessitated the exploration of alternative antimicrobial agents, particularly natural products like essential oils. This study investigated the antibacterial potential of a unique blend of four essential oils (EOB) across a gradient of concentrations (0.1 to 50%) against Gram-positive and Gram-negative bacteria using an adapted broth microdilution method, minimum inhibitory concentrations (MICs), and 24-h growth assays. The Gram-positive bacteria were Staphylococcus epidermidis and Bacillus subtilis, while the Gram-negative bacteria were Escherichia coli and Klebsiella aerogenes. The results demonstrated that the EOB exerted a concentration-dependent inhibitory effect on bacterial growth, with MICs determined at 25% for all the species tested. Growth curve analysis revealed that lower concentrations of the EOB (0.1 to 0.78%) allowed for normal bacterial proliferation, while at intermediate concentrations (1.56 to 3.13%), inconsistent trends in growth were exhibited. At higher concentrations (25 and 50%), the EOB effectively halted bacterial growth, as indicated by flat growth curves. The increase in the lag phase and the decrease in the growth rate at a sub-MIC concentration (12.5%) suggest a significant effect on bacterial adaptation and survival. Relative fitness analyses further highlighted the inhibitory effects of higher essential oil concentrations. S. epidermidis and E. coli had a significant (p < 0.05) reduction in fitness starting from the 6.25% concentration, while the other two species experienced a significant (p < 0.001) reduction in relative fitness from a concentration of 12.5%. These findings underscore the potential of this EOB as an effective antimicrobial agent, particularly in the context of rising antibiotic resistance. Furthermore, the study suggests that the EOB used in the present study could be integrated into therapeutic strategies as a natural alternative or adjunct to traditional antibiotics, offering a promising avenue for combating resistant bacterial strains.

Impact of Infection on Survival Outcomes in High-Grade Gliomas: A Retrospective Analysis of 26 Cases in Our Fifteen-Year Experience-Janus Faced Phenomenon

BACKGROUND/OBJECTIVES

Glioblastoma IDH-wildtype CNS WHO grade 4 and astrocytoma IDH-mutant WHO grade 4 (together, high-grade gliomas: HGGs) are the most prevalent malignant brain tumors, carrying a poor prognosis despite multimodal treatment. Surgical site infections (SSIs) represent a relative frequent postoperative complication in HGG patients. Despite multimodal treatment protocols combining surgery, radiotherapy, and temozolomide chemotherapy, HGGs remain associated with a dismal prognosis, underscoring the need to evaluate how SSIs impact disease progression and survival outcomes. This study's aim was to investigate the influence of SSIs on the clinical course of patients with HGGs.

METHODS

A comprehensive review of medical records for HGG patients treated at our institution between 2010 and 2024 identified 26 patients with SSIs. These patients were compared to an age-matched control group with the same histological diagnosis and treatment regimen. This study analyzed overall survival (OS), microbiological data, and pathological parameters to assess the impact of SSIs on patient outcomes. Survival differences between the infected and non-infected groups were evaluated using Kaplan-Meier survival curves. Remarkably, three patients with exceptionally long overall survival were highlighted in this study.

RESULTS

Among the cohort of 2008 patients with HGG surgery, 26 patients developed SSIs. An age-matched control group of 26 patients was identified, none of whom experienced SSIs. Comparing the OS between the infected and uninfected groups, a statistically significant improvement in OS was observed in the infected group (p = 0.049). The median OS in the infected group was 388 days, slightly shorter than the median OS of 422 days in the control group. However, the mean OS was markedly higher in the infected group (674 days) compared to the control group (442 days). The standard deviation of OS in the infected group was notably expansive, indicating substantial variability in survival outcomes. A cluster of infected patients with SSIs near the time of diagnosis had shorter OS, while other infected cases demonstrated significantly longer survival, exceeding both median and mean OS values. In contrast, the uninfected group showed limited standard deviation values, with uniformly distributed individual OS data around the median and mean values. Expectedly, IDH mutation status significantly influenced the survival in cohort patients. However, when stratified by infection status, no association between IDH mutation and improved infection-related survival was identified. The microbiological profile of SSIs was diverse, encompassing Gram-positive and Gram-negative bacteria as well as aerobic and anaerobic organisms.

CONCLUSIONS

These findings underscore the heterogeneity of infection-related outcomes and their potential impact on survival in HGG patients. According to our knowledge, our study is one of the largest retrospective studies to date investigating and confirming the significant relationship between SSIs and HGG patients' survival. Our results confirm the Janus Face phenomenon of infections, having both negative and positive effects depending on the context.

Evaluation of the microbial contamination of the audiological diagnostic equipment and their current disinfection techniques

BACKGROUND

The study aims to investigate the microbial contamination of commonly used audiological diagnostic equipment and to evaluate the effectiveness of existing disinfection methods in audiological clinics.

METHODS

Hospitals with fully equipped audiology clinics in Istanbul were included in the study. Various audiological diagnostic devices and disinfection practices in hospitals were examined. A total of 60 swab samples were collected from the stimulus button on the audiometer, patient response switch, supra-aural headphone cushion, bone conduction headphone, and disinfected probe tips used in the Tympanometer and Auditory Brainstem Response.

RESULTS

Bacterial growth was observed on 40% of the analyzed plates, with 11.66% showing 2 different types of bacterial growth. Staphylococcaceae family were the most common bacteria identified. Other bacteria included Pseudomonas putida, Pantoea spp., Micrococcus luteus, Corynebacterium spp., and Bacillus spp. The highest bacterial growth occurred on the supra-aural headphone cushion and bone vibrator.

CONCLUSIONS

The study highlights the presence of various bacteria on audiological diagnostic equipment, emphasizing Staphylococcus species as predominant. Current disinfection practices, particularly for supra-aural headphones and bone vibrators, were found to be inadequate, potentially posing risks for infections. The study suggests the need for disinfection protocols, particularly for frequently touched devices, to ensure patient safety in clinics.

Identification of body fluid sources based on microbiome antibiotic resistance genes using high-throughput qPCR

Identifying the origin of body fluids is a critical step in forensic investigation. Recently, the development of high-throughput sequencing technology has led to the use of microbiomes for body fluid identification in forensic studies. However, high-throughput sequencing data are difficult to analyze, the sequencing protocol is complicated. An increasing number of studies have focused on antibiotic resistance genes (ARGs) in the human microbiome. The abundance and diversity of ARGs in different parts of the human body can be detected using quantitative polymerase chain reaction (qPCR). To date, no studies have inferred the sources of body fluids based on ARGs. Therefore, we attempted to use ARGs as a tool to infer the origin of body fluids. We assessed the abundance and diversity of 64 ARGs in blood, semen, saliva, vaginal secretions (VS), nasal secretions (NS), and fecal samples using high-throughput qPCR. The results showed that ARGs were more diverse in fecal samples, which was significantly higher than those of other sample types (P < 0.05). Principal coordinate analysis (PCoA) showed that the samples clustered mainly according to their type. We constructed a random forest classification model based on 64 ARGs with a prediction accuracy of 92.68 %. Next, we evaluated the importance of the features in the random forest model (mean decrease accuracy, MDA). Subsequently, we constructed prediction models for the top 40 and 20 ARGs after sorting genes with the highest MDA, and their prediction accuracies were both 92.68 %. The accuracy of the top 10 ARGs was 87.80 %. Notably, when only the top 10 characterized ARGs were used to construct models for saliva, semen, and VS samples, the prediction accuracy reached was 95.24 %. This shows that blood, semen, saliva, NS, VS, and fecal samples can be accurately identified using ARGs. Our results suggest that ARGs are promising markers for forensic body fluid identification.

Conversation between skin microbiota and the host: from early life to adulthood

Host life is inextricably linked to commensal microbiota, which play a crucial role in maintaining homeostasis and immune activation. A diverse array of commensal microbiota on the skin interacts with the host, influencing the skin physiology in various ways. Early-life exposure to commensal microbiota has long-lasting effects, and disruption of the epidermal barrier or transient exposure to these microorganisms can lead to skin dysbiosis and inflammation. Several commensal skin microbiota have the potential to function as either commensals or pathogens, both influencing and being influenced by the pathogenesis of skin inflammatory diseases. Here we explore the impact of various commensal skin microbiota on the host and elucidate the interactions between skin microbiota and host systems. A deeper understanding of these interactions may open new avenues for developing effective strategies to address skin diseases.

Role of the microbiome in regulation of the immune system

Immune health and metabolic functions are intimately connected via diet and the microbiota. Immune cells are continuously exposed to a wide range of microbes and microbial-derived compounds, with important mucosal and systemic ramifications. Microbial fermentation of dietary components in vivo generates thousands of molecules, some of which are integral components of the molecular circuitry that regulates immune and metabolic functions. These in turn protect against aberrant inflammatory or hyper-reactive processes and promote effector immune responses that quickly eliminate pathogens, such as SARS-CoV-2. Potent tolerance mechanisms should ensure that these immune cells do not over-react to non-pathogenic factors (e.g. food proteins), while maintaining the ability to respond to infectious challenges in a robust, effective and well controlled manner. In this review we examine the factors and mechanisms that shape microbiota composition and interactions with the host immune system, their associations with immune mediated disorders and strategies for intervention.

A Molecularly Imprinted Polymer Nanobodies (nanoMIPs)-Based Electrochemical Sensor for the Detection of Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) contamination is commonly found on human skin and medical devices. Herein, we present a sensor utilizing molecularly imprinted polymer nanobodies (nanoMIP) for recognition and electrochemical impedance spectroscopy (EIS) to detect S. epidermidis. Sensor manufacturing involves synthesizing nanoMIP via solid-phase synthesis using whole bacteria as templates. Screen-printed gold electrode (AuSPE)-modified 16-mercaptohexadecanoic acid (MHDA) served to immobilize the nanoMIPs on the sensor surface through an amide bond, with the remaining functional groups blocked by ethanolamine (ETA). Scanning electron microscope (SEM) analysis of the modified AuSPE surface reveals immobilized spherical nanoMIP particles of 114-120 nm diameter, while atomic force microscope (AFM) analysis showed increased roughness and height compared to bare AuSPE. The sensor is selective for S. epidermidis, with a remarkable detection limit of 1 CFU/mL. This research demonstrates that the developed nanoMIP-based sensor effectively detects S. epidermidis. Further research will focus on developing protocols to integrate the nanoMIP-based EIS sensor into medical and industrial applications, ultimately contributing to improved safety for both humans and animals in the future.

Exploring Peri-Implantitis Risk-Factors: A Cross-Sectional Study

Background/Objectives: With the increasing use of dental implants in edentulous patients and the high prevalence of peri-implantitis, understanding its microbial and risk factors is crucial. This study investigated Romanian patients from two private dental clinics in Cluj-Napoca, Romania, diagnosed with peri-implantitis, focusing on identifying the predominant bacterial species at affected sites compared with healthy implant sites. Additionally, we examined the impact of factors such as smoking, gender, age, and prosthetic restoration type on disease prevalence. Methods: This cross-sectional study, conducted between January 2023 and December 2024, included randomly selected patients who met the predefined inclusion and exclusion criteria. We enrolled 22 patients and 50 implants in the study. Data collected from medical records, clinical evaluations, and microbiological assessments were subsequently entered into a computerized database. Clinical data were analyzed using Social Science Statistics software(Jeremy Staangroom 2018). Bacterial samples were assessed, incubated, and subsequently identified using the Vitek 2 Compact System (BioMérieux, Marcy-l' Étoile, France). Results: Peri-implantitis incidence was found to be independent of gender, more prevalent in the mandible, and equally affected smokers and non-smokers. The disease involves a complex polymicrobial infection, with pathogenic bacteria triggering the condition and opportunistic bacteria sustaining it. Conclusions: Peri-implantitis is a complex polymicrobial infection that arises from the interaction of strict pathogenic bacteria and opportunistic bacteria. Peri-implantitis results from intricate interactions of local, systemic, and microbial factors. Identifying its causes is essential for developing effective treatments, with future research emphasizing the role of opportunistic bacteria in disease progression.

Synergistic activity of dispersin B and benzoyl peroxide against Cutibacterium acnes/Staphylococcus epidermidis dual-species biofilms

Cutibacterium acnes plays a key role in the development of acne vulgaris, with biofilm formation contributing to its persistence and resistance to antimicrobial treatments. A critical component of C. acnes biofilms is poly-N-acetylglucosamine (PNAG), an exopolysaccharide that facilitates both biofilm stability and biocide resistance. This study evaluated the efficacy of the PNAG-degrading enzyme dispersin B in enhancing the susceptibility of C. acnes biofilms to benzoyl peroxide (BP), a common anti-acne agent. Dual-species biofilms of C. acnes and Staphylococcus epidermidis, which has been shown to promote C. acnes biofilm growth under aerobic conditions, were cultivated in glass tubes and treated with dispersin B (5-80 µg/mL), BP (0.1-2.5%), or a combination of both. Dispersin B or BP alone reduced C. acnes colony-forming units (CFUs) by 1-2 log units. However, sequential treatment with dispersin B followed by BP achieved a synergistic effect, yielding a >6-log reduction in CFUs. Remarkably, concentrations as low as 5 µg/mL dispersin B combined with 0.5% BP efficiently eradicated C. acnes from the dual-species biofilms. These findings highlight the protective role of PNAG against BP and demonstrate the potential of dispersin B as an adjunctive therapy to enhance the efficacy of BP in acne treatment.

Bioinspired Fe3O4@Ag@ indocyanine green/adenosine triphosphate nanoenzyme in synergistic antibacterial performance

Metal-based nanoenzymes with excellent biocompatibility and stable chemical properties are an effective antimicrobial agent against bacterial resistance due to their radical-mediated catalysis. In this work, due to the pH of most bacterial infection sites being close to neutral, targeting the problem of Fe3O4@Ag difficulty in maintaining the catalytic activity of nanoenzymes in neutral environments, we prepare a novel multifunctional Fe3O4@Ag@ indocyanine green/adenosine triphosphate peroxidase nanoenzymes for synergistic antibacterial activity. ICG (Indocyanine Green) and ATP (Adenosine triphosphate) are adsorbed on the surface of Fe3O4@Ag through electrostatic adsorption to form its structure. The cell viability remained above 90%, indicating its good biocompatibility. By complexing ATP with nanoenzymes to participate in single electron transfer and binding with Fe (II), ATP promotes the sudden release of hydroxyl radical (·OH) from the system, successfully transferring Fe3O4@Ag the peroxidase activity of nanoenzymes extends to neutral pH. By utilizing ICG as a photosensitizer and a sonosensitizer, under the combined treatment of near-infrared light and ultrasound, the photodynamic therapy (PDT)/photothermal therapy (PTT)/sonodynamic therapy (SDT) functions can be achieved, achieving multifunctional synergistic antibacterial effects. In a neutral environment, its bactericidal efficiency against Gram negative (Escherichia coli) and Gram positive (Staphylococcus aureus) is 99.9% and 99.7%, respectively, providing a new multi-mode synergistic antibacterial strategy for bacterial infections.

A new bacteriophage infecting Staphylococcus epidermidis with potential for removing biofilms by combination with chimeric lysin CHAPSH3b and vancomycin

Staphylococcus epidermidis is the cause of serious skin and prosthetic joint infections despite being a common inhabitant of human body surfaces. However, both the rise in antibiotic resistance in this species and its ability to form biofilms are increasingly limiting the available therapeutic options against these illnesses. In this landscape, phage therapy stands out as an interesting alternative to antibiotics. In the present study, we report the isolation and characterization of a novel virulent phage infecting S. epidermidis (Staphylococcus phage IPLA-AICAT), which belongs to the Herelleviridae family. The estimated genome size of this virus is 139,941 bp, and sequence analysis demonstrated the absence of antibiotic resistance genes and virulence factors. This phage infects a high proportion (79%) of clinically relevant S. epidermidis strains and exhibits antibiofilm activity. Moreover, a combination of this phage with other antimicrobials, i.e., vancomycin and the lytic protein CHAPSH3b, further improved the reduction in surface-attached bacteria. Notably, the combination of Staphylococcus phage IPLA-AICAT (109 PFU/mL) and CHAPSH3b (8 µM), originally designed to target Staphylococcus aureus, was able to reduce the number of viable cells by 3.06 log units in 5-h-old biofilms. In 24-h-old biofilms, the reduction was also significant after 6 h of treatment (2.06 log units) and 24 h of treatment (2.52 log units). These results confirm our previous data regarding the potential of phage-lysin mixtures against staphylococcal biofilms.IMPORTANCEStaphylococcus epidermidis is one of the main causes to device-associated infections mostly due to its ability to form stable biofilms attached to human tissues. Besides the inherent antimicrobial tolerance of biofilms, this microorganism is also increasingly becoming resistant to standard-of-care antibiotics. To fight against this problem, phage therapy is a viable option to complement the available antibiotics in the treatment of recalcitrant infections. This work describes a new phage infecting S. epidermidis clinical strains that is a member of the Herelleviridae family and the combination with other antimicrobials to further improve the reduction of biofilms. Together with the significant progress achieved in the development of diagnostic tools, phages and their derived proteins will bring us much closer to a therapeutic landscape in which we are not so heavily reliant on antibiotics to combat bacterial pathogens.

The characteristics of surgical site infection with class I incision in neurosurgery

OBJECTIVE

Surgical site infections (SSIs) were recognized to be the most common complication of neurological surgery, with substantial life quality threats to patients and additional cost burdens to healthcare facilities. This study sought to expound the infection characteristics of class I incision and provide clinical indication for the prevention and treatment of SSIs.

METHODS

A 2-year retrospective analysis was conducted according to patients who performed neurological surgery with class I incision in a tertiary comprehensive hospital in Shaanxi Province, China. Case mix index (CMI)-adjusted and national nosocomial infection surveillance (NNIS) risk index-adjusted SSI rate were utilized for analytical standardization. The SSIs were specifically analyzed according to various departments, surgeons, and surgical classifications.

FINDINGS

6046 surgical cases were finally included in our study. The majority of the American Society of Aneshesiologists (ASA) score and NNIS risk index of surgeries were allocated in level 2 and score 1. Our study found 121 SSI cases, with the crude infection rate of 2.00%. 95.04% were organ/space infection. The most of the infection were found in the surgeries with score 1 (68.60%) of the NNIS risk index. The main surgical classification was resection of space occupying lesions (61.96%). The highest crude and NNIS risk index adjusted infection were individually found in hybrid operation (11.67%) and endoscopy-assisted resection of space occupying lesions (13.33%). 21 of 54 surgeons were found to have SSIs. We found the main pathogenic bacteria was Staphylococcus epidermidis (22.81%), and the commonly prophylactic used antibiotics was Cefazolin (51.95%).

CONCLUSION

Our study found the main infection was among surgeries with score 1 of NNIS risk index and the surgical classification of endoscopy-assisted resection of space occupying lesions. We indicated specific attention should be paid to the surgeon and surgical classification with highest infection rate to control and prevent SSIs.

Genomic and phenotypic characterization of staphylococci isolated from the skin of non-human primates

The growth of wildlife tourism coupled with continued deforestation has resulted in increased contact between non-human primates (NHPs) and humans. Such events may promote the transmission of potentially pathogenic bacteria such as Staphylococcus spp. However, the presence and associated virulence of staphylococci associated with NHPs remain poorly characterized. To help address this, we isolated staphylococci from the skin of four NHP species housed at a UK zoo and characterized their antimicrobial resistance, virulence factors and prophage. We recovered 82 isolates from mannitol salt agar, of which 28 were tentatively confirmed as staphylococci by 16S rRNA gene sequencing. Fourteen isolates were determined to be unique, based on differences in their 16S rRNA gene sequences and origins of isolation. Whole-genome sequencing of the 14 isolates and subsequent genomic analysis identified 5 species, belonging to the genus Staphylococcus (Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus pasteuri, Staphylococcus saprophyticus and Staphylococcus warneri). Bioinformatic prediction of antimicrobial resistance genes identified a total of 85 resistance determinants across all 14 isolates, potentially rendering them resistant to a range of antibiotic classes. However, phenotypic testing revealed only a single case of clinical resistance. Isolates belonging to the species S. pasteuri were identified as the most proficient biofilm formers. Potentially complete prophages were identified in 11 of the sequenced isolates. Prophage JCT0104_p1, identified within the genome of S. aureus JCT0104, was found to encode the virulence factor staphylokinase, which is associated with pathogenesis in humans. Our findings contribute to the limited knowledge of the diversity and characteristics of staphylococci residing on the skin of captive NHPs.

Bacteriuria and antibiotic use during the third wave of COVID-19 intensive care in Sweden

BACKGROUND

Urinary tract infections (UTIs) are prevalent among patients carrying indwelling catheters in the intensive care unit (ICU). This study investigates antibiotic use and bacterial colonisation among ICU patients during the third wave of the COVID-19 pandemic, building on our prior discovery of increased Enterococcus colonisation associated with increased cephalosporin use in early COVID-19.

METHODS

Longitudinal urine samples from COVID-19 patients (n = 109) with transurethral catheterisation were analysed for bacterial prevalence, further identified via MALDI-TOF. Microbiological results were combined with clinical data obtained daily, assessed and compared with COVID-19 waves 1 and 2.

RESULTS

Patients in wave 3 exhibited improved outcomes compared to those in waves 1 and 2, alongside a decrease in antibiotic use. Staphylococcus emerged as the primary bacterium and early colonizer of the urinary tract, potentially due to the absence of antibiotic treatment. Our results imply that length of stay (LOS) correlates solely with enteric pathogens and that antibiotic treatment correlates with colonisation by certain uropathogens, whereas the absence of antimicrobial therapy is associated with rapid colonisation of skin flora. Polymicrobial colonisation was common, predominantly involving Gram-positive bacteria.

CONCLUSION

Our findings underscore the complexity of bacteriuria in ICU patients, advocating for targeted surveillance and tailored antibiotic approaches to mitigate UTI risk. Insights into antibiotic use and bacterial colonisation are vital for optimising stewardship practices, combating antimicrobial resistance, and enhancing ICU patient outcomes.

Do Melanocytes Have a Role in Controlling Epidermal Bacterial Colonisation and the Skin Microbiome?

In addition to producing melanin to protect epidermal keratinocytes against DNA damage, melanocytes may have important roles in strengthening innate immunity against pathogens. We have developed a functional, pigmented, human full-thickness 3D skin equivalent to determine whether the presence of melanocytes impacts epidermal bacterial growth and regulates the expression of genes involved in the immune response. We introduced primary epidermal melanocytes to construct a 3-cell full-thickness skin equivalent with primary dermal fibroblasts and epidermal keratinocytes. Immunohistochemistry verified the appropriate ratio and spatial organisation of melanocytes. Alpha-MSH induced melanogenesis, confirming an appropriate physiological response. We compared this 3-cell skin equivalent with the 2-cell version without melanocytes in response to inoculation with 3 species of bacteria: Staphylococcus epidermidis, Corynebacterium striatum, and Cutibacterium acnes. There was a significant decrease in the colonisation of bacteria in the skin equivalents containing functional melanocytes. There was increased expression of immune-response genes (S100A9, DEFB4A, IL-4R) following microorganism exposure; however, there were marked differences between the unpigmented and pigmented skin equivalents. This physiologically relevant human 3D-skin equivalent opens up new avenues for studying complex skin pigmentation disorders, melanoma, and UV damage, as well as the rapidly evolving field of the skin microbiome and the balance between commensal and pathogenic species.

The in vitro synergistic and antibiofilm activity of Ceftazidime/avibactam against Achromobacter species recovered from respiratory samples of cystic fibrosis patients

PURPOSE

Achromobacter spp. may form biofilm in patients' respiratory tracts and cause serious infections. This research examined the bactericidal and synergistic effects of ceftazidime/avibactam (CZA) alone and in combination with different antibiotics against Achromobacter spp.

METHODS

MICs of 52 Achromobacter spp. were determined by broth microdilution. In-vitro time-kill curve experiments assessed CZA's bactericidal and synergistic properties alone and in combination with other antibiotics. Moreover, the antibiofilm activity of CZA alone or in combination with the antibiotics was assessed with using microplate method.

RESULTS

Based on MIC90 values, CZA exhibited four times greater in-vitro activity against tested strains than ceftazidime. The most effective agent was meropenem, with a 92% susceptibility level on the tested strains. On the other hand, ciprofloxacin was found to be bactericidal at both 1 × and 4xMIC concentrations. CZA, chloramphenicol and meropenem were observed to have bactericidal effects alone at 4xMIC concentrations against the tested isolates. CZA + CS and CZA + MEM showed synergy in three out of five and two out of five strains tested at 1xMIC, respectively. Furthermore, the pairing of CZA with colistin, CZA with meropenem and CZA with ciprofloxacin exhibited a synergistic impact at 4xMIC. Moreover, combination therapy CZA with the tested antibiotics showed reduced biofilm formation in a concentration-dependent manner at 24 h.

CONCLUSION

The outcomes of this research also suggest that CZA plus colistin, meropenem, or ciprofloxacin were more productive against Achromobacter strains. To our knowledge, this is the first article to evaluate the synergistic and antibiofilm activities of CZA alone or in combination with different agents against Achromobacter species.

Dynamically Assembling Magnetic Nanochains as New Generation of Swarm-Type Magneto-Mechanical Nanorobots Affecting Biofilm Integrity

Bacterial resistance is gaining ground and novel, unconventional strategies are required to improve antibiotic treatments. As a synthetic analog of planktonic bacilli, the natural bacterial swimmers that can penetrate bacterial biofilms, ultra-short propelling magnetic nanochains are presented as bioinspired magnetic nanorobots, enhancing the antibiotic treatment in biofilm-forming Staphylococcus epidermidis. Propelling nanochains, activated by a low intensity (<20 mT) and low frequency (<10 Hz) rotating magnetic field (RMF), prompt the otherwise resistant biofilm-forming bacteria to become sensitive to methicillin, resulting in the killing of 99.99% of bacteria. While magnetic force-driven spherical magnetic nanoparticles were previously reported as unidirectional biofilm channel diggers, propelling nanochains emerge as second-generation magnetic nanorobots, which, due to their magnetic core, shape anisotropy, and negative zeta potential, combine magnetic responsiveness, torque-driven movement, and attractive electrostatic interactions to attach to bacterial aggregates and multi-directionally protrude throughout the biofilm, indulging mechanical forces. These synergistic effects, in combination with an antibiotic drug, destroy the bacterial extracellular matrix and eradicate the formed biofilm, as confirmed with several complementary techniques.

Estimating nosocomial transmission of micro-organisms in hospital settings using patient records and culture data

Pathogenic bacteria are a major threat to patient health in hospitals. Here we leverage electronic health records from a major New York City hospital system collected during 2020-2021 to support simulation inference of nosocomial transmission and pathogenic bacteria detection using an agent-based model (ABM). The ABM uses these data to inform simulation of importation from the community, nosocomial transmission, and patient spontaneous decolonization of bacteria. We additionally use patient clinical culture results to inform an observational model of detection of the pathogenic bacteria. The model is coupled with a Bayesian inference algorithm, an iterated ensemble adjustment Kalman filter, to estimate the likelihood of detection upon testing and nosocomial transmission rates. We evaluate parameter identifiability for this model-inference system and find that the system is able to estimate modelled nosocomial transmission and effective sensitivity upon clinical culture testing. We apply the framework to estimate both quantities for seven prevalent bacterial pathogens: Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus (both sensitive, MSSA, and resistant, MRSA, phenotypes), Enterococcus faecium and Enterococcus faecalis. We estimate that nosocomial transmission for E. coli is negligible. While bacterial pathogens have different importation rates, nosocomial transmission rates were similar among organisms, except E. coli. We also find that estimated likelihoods of detection are similar for all pathogens. This work highlights how fine-scale patient data can support inference of the epidemiological properties of micro-organisms and how hospital traffic and patient contact determine epidemiological features. Evaluation of the transmission potential for different pathogens could ultimately support the development of hospital control measures, as well as the design of surveillance strategies.

Bacterial Diversity of Marine Biofilm Communities in Terra Nova Bay (Antarctica) by Culture-Dependent and -Independent Approaches

Applying both culture-independent and -dependent approaches, bacterial diversity of marine biofilm communities colonising polyvinyl chloride panels submerged in Terra Nova Bay (Ross Sea, Antarctica) was investigated. Panels were deployed in two sites subjected to a different degree of anthropogenic impact (Road Bay [RB] impacted site and Punta Stocchino [PTS] control site). Biofilm samples were collected after 3 or 12 months to evaluate both short- and long-term microbial colonisation. Taxonomic composition of the microbial community was studied by 16S rRNA gene amplicon sequencing. Proteobacteria was the predominant phylum, followed by Bacteroidetes, Actinobacteria, Verrucomicrobia and Firmicutes. Impacted RB biofilms were found to contain a relevant fraction of potentially pathogenic bacterial genera, accounting for 27.49% of the whole community. A total of 86 psychrotolerant bacterial strains were isolated from the biofilm samples using culture-dependent techniques designed to enrich in Actinobacteria. These strains were assigned to three different phyla: Actinobacteria (54.65%), Firmicutes (32.56%) and Proteobacteria (12.79%). 2.73% of genera identified by metabarcoding were recovered also through cultivation, while 11 additional genera were uniquely yielded by cultivation. Functional screening of the isolates revealed their hydrolytic and oxidative enzyme activity patterns, giving new insights into the metabolic and biotechnological potential of microbial biofilm communities in Terra Nova Bay seawater.

Transparent and visible light-activated antimicrobial air filters from electrospun crystal violet-embedded polyacrylonitrile nanofibers

Bioaerosols pose significant risks to indoor environments and public health, driving interest in advanced antimicrobial air filtration technologies. Conventional antimicrobial filters often suffer from diminished efficacy over time and require additional binders to retain antimicrobial agents. This study introduces CV@PAN, a self-disinfecting nanofiber fabricated via electrospinning of crystal violet (CV) and polyacrylonitrile (PAN). The process effectively incorporated CV into the PAN framework, minimizing environmental release. We comprehensively analyzed the physical and chemical properties of CV@PAN nanofibers, including fiber morphology, size distribution, chemical composition, thermal stability, and transparency. The CV@PAN nanofibers exhibited an average diameter of 0.28 μm. The fabricated filter achieved a bioaerosol removal efficiency of >99.2% against Staphylococcus epidermidis, with a low-pressure drop of 401.6 Pa at a face velocity of 16 cm/s. The filter demonstrated an optical transparency exceeding 50%. Upon visible light exposure, the embedded CV generated reactive oxygen species, resulting in an antibacterial efficacy of >99.9%. These findings demonstrate the significant potential of CV@PAN nanofiber filters for air quality management and their promise as an advancement in antibacterial air filtration technology.

Bilateral Calcified Subdural Empyemas: A Case Report and Literature Review

Calcified subdural empyemas (CSEs) are rare neurosurgical pathologies that can be mistaken for calcified chronic subdural hematomas. Patients often present with symptoms of worsening headache, seizures, or hemiparesis without general malaise or systemic illness. Here we report the tenth documented case of CSE in a 51-year-old man from South Africa with no surgical history who developed bilateral, culture-positive collections. Additionally, we provide a review of the current literature on this condition. The majority of CSEs occur in males from developing countries who previously underwent neurosurgical procedures decades earlier. Further investigations into the pathophysiology of this unique disease are warranted.

The Unique Capability of Endolysin to Tackle Antibiotic Resistance: Cracking the Barrier

The lack of new antibacterial medicines and the rapid rise in bacterial resistance to antibiotics pose a major threat to individuals and healthcare systems. Despite the availability of various antibiotics, bacterial resistance has emerged for almost every antibiotic discovered to date. The increasing prevalence of multidrug-resistant bacterial strains has rendered some infections nearly untreatable, posing severe challenges to health care. Thus, the development of alternatives to conventional antibiotics is critical for the treatment of both humans and food-producing animals. Endolysins, which are peptidoglycan hydrolases encoded by bacteriophages, represent a promising new class of antimicrobials. Preliminary research suggests that endolysins are more effective against Gram-positive bacteria than Gram-negative bacteria when administered exogenously, although they can still damage the cell wall of Gram-negative bacteria. Numerous endolysins have a modular domain structure that divides their binding and catalytic activity into distinct subunits, which helps maximize their bioengineering and potential drug development. Endolysins and endolysin-derived antimicrobials offer several advantages as antibiotic substitutes. They have a unique mechanism of action and efficacy against bacterial persisters (without requiring an active host metabolism); subsequently, they target both Gram-positive and Gram-negative bacteria (including antibiotic-resistant strains), and mycobacteria. Furthermore, there has been limited evidence of endolysin being resistant. Because these enzymes target highly conserved links, resistance may develop more slowly compared to traditional antibiotics. This review provides an overview and insight of the potential applications of endolysins as novel antimicrobials.

Codon usage analysis in selected virulence genes of Staphylococcal species

The Staphylococcus genus, composed of Gram-positive bacteria, includes several pathogenic species such as Staphylococcus aureus, S. epidermidis, S. haemolyticus, and S. saprophyticus, each implicated in a range of infections. This study investigates the codon usage patterns in key virulence genes, including Autolysin (alt), Elastin Binding protein (EbpS), Lipase, Thermonuclease, Intercellular Adhesion Protein (IcaR), and V8 Protease, across four Staphylococcus species. Using metrics such as the Effective Number of Codons (ENc), Relative Synonymous Codon Usage (RSCU), Codon Adaptation Index (CAI), alongside neutrality and parity plots, we explored the codon preferences and nucleotide composition biases. Our findings revealed a pronounced AT-rich codon preference, with AT-rich genomes likely aiding in energy-efficient translation and bacterial survival in host environments. These insights provide a deeper understanding of the evolutionary adaptations and translational efficiency mechanisms that contribute to the pathogenicity of Staphylococcus species. This knowledge could pave the way for novel therapeutic interventions targeting codon usage to disrupt virulence gene expression.

Assembly landscape of the complete B-repeat superdomain from Staphylococcus epidermidis strain 1457

The accumulation-associated protein (Aap) is the primary determinant of Staphylococcus epidermidis device-related infections. The B-repeat superdomain is responsible for intercellular adhesion that leads to the development of biofilms occurring in such infections. It was recently demonstrated that Zn-induced B-repeat assembly leads to formation of functional amyloid fibrils, which offer strength and stability to the biofilm. Rigorous biophysical studies of Aap B-repeats from S. epidermidis strain RP62A revealed Zn-induced assembly into stable, reversible dimers and tetramers, prior to aggregation into amyloid fibrils. Genetic manipulation is not tractable for many S. epidermidis strains, including RP62A; instead, many genetic studies have used strain 1457. Therefore, to better connect findings from biophysical and structural studies of B-repeats to in vivo studies, the B-repeat superdomain from strain 1457 was examined. Differences between the B-repeats from strains RP62A and 1457 include the number of B-repeats, which has been shown to play a critical role in assembly into amyloid fibrils, as well as the distribution of consensus and variant B-repeat subtypes, which differ in assembly competency and thermal stability. Detailed investigation of the Zn-induced assembly of the full B-repeat superdomain from strain 1457 was conducted using analytical ultracentrifugation. Whereas the previous construct from RP62A (Brpt5.5) formed a stable tetramer prior to aggregation, Brpt6.5 from 1457 forms extremely large stable species on the order of ≈28-mers, prior to aggregation into similar amyloid fibrils. Our data suggest that both assembly pathways may proceed through the same mechanism of dimerization and tetramerization, and both conclude with the formation of amyloid-like fibrils. Discussion of assembly behavior of B-repeats from different strains and of different length is provided with considerations of biological implications.

Bidirectional Mendelian Randomization Analysis to Study the Relationship Between Human Skin Microbiota and Radiation-Induced Skin Toxicity

Radiation-induced skin toxicity, resulting from ionizing or nonionizing radiation, is a common skin disorder. However, the underlying relationship between skin microbiota and radiation-induced skin toxicity remains largely unexplored. Herein, we uncover the microbiota-skin interaction based on a genome-wide association study (GWAS) featuring 150 skin microbiota and three types of skin microenvironment. Summary datasets of human skin microbiota were extracted from the GWAS catalog database, and summary datasets of radiation-induced skin toxicity from the FinnGen biobank. Mendelian Randomization (MR) analysis was leveraged to sort out the causal link between skin microbiota and radiation-induced skin toxicity. We identified 33 causal connections between human skin microbiota and radiation-induced skin toxicity, including 19 positive and 14 negative causative directions. Among these potential associations, the genus Staphylococcus could serve as a common risk factor for radiation-induced skin toxicity, especially for radiodermatitis. And Streptococcus salivarius was identified as a potential protective factor against radiation-induced skin toxicity. Additional analysis indicated no pleiotropy, heterogeneity, or reverse causal relationship in the results. We comprehensively assessed potential associations of skin microbiota with radiation-induced skin toxicity and identified several suggestive links. Our results provide promising targets for the prevention and treatment of radiation-induced skin toxicity.

Molecular characterization and genotype of multi-drug resistant Staphylococcus epidermidis in nasal carriage of young population, Mahasarakham, Thailand

Staphylococcus epidermidis, a coagulase-negative staphylococcus, is a prevalent skin commensal that has increasingly been recognized as a significant pathogen, particularly in hospital environments, where it is associated with device-related infections. The emergence of multi-drug resistance and its ability to form biofilms complicate the clinical management of infections caused by this organism, posing a growing public health concern. This study aimed to investigate the nasal carriage of S. epidermidis among healthy young individuals and to analyze its antibiotic resistance patterns, resistance genes, and biofilm formation capabilities. Nasal swabs were collected from 40 undergraduate students at Mahasarakham University, Thailand, aged between 20 and 22 years. A total of 38 isolates were confirmed as S. epidermidis through both phenotypic and molecular characterization. Antibiotic susceptibility testing demonstrated resistance to various classes of antimicrobials, including beta-lactams, macrolides, and tetracyclines. Notably, five isolates exhibited methicillin resistance S. epidermidis (MRSE). Resistance genes, such as mecA, ermA, tetM, tetL, and tetK, were identified across the isolates, contributing to the observed resistance profiles. Biofilm formation assays revealed that most isolates displayed weak to moderate biofilm formation, with only one isolate demonstrating strong biofilm-forming capacity. Genetic analysis indicated a significant correlation between biofilm formation and the presence of the icaA gene, which is crucial for biofilm production. This study suggests the necessity for ongoing surveillance of nasal carriage of S. epidermidis to enhance understanding of its role in the dissemination of antimicrobial resistance and biofilm-associated infections, particularly within healthcare settings.

RF pulsed plasma modified composite scaffold for enhanced anti-microbial activity and accelerated wound healing

Infected wounds present significant challenges pertaining to healing and often demand administration of strong antibiotics to patients. Also, drug resistant microbes may alter the physiology of wounds to create biofilms, frequently leading to high morbidity and mortality. In this investigation, a biodegradable, microporous composite agarose-chitosan scaffold was fabricated. Furthermore, its surface was modified with diphenyldiselenide deposition, using low pressure pulsed plasma technology. The optimized plasma parameters, viz. 5ON/15OFF (ms) of plasma pulse rate and 80 min of treatment time resulted in scaffolds having enhanced anti-bacterial activity against gram positive microbes like Staphylococcus (S.) aureus and S. epidermidis. The scaffolds were non-toxic to skin cells, as confirmed by the MTT assay. Cell proliferation through plasma treated and untreated scaffolds was assessed by culturing primary human dermal fibroblasts (HdaF) and human keratinocytes (HaCaT) and visualizing via confocal microscopy. Moreover, in-vivo rat model confirmed accelerated wound healing with plasma treated scaffold (100 % on day 14), as compared to the untreated scaffold (100 % on day 16) when compared with over-the-counter (OTC) ointment Betadine (100 % on day 12).

Splash Basins in the Operating Room: Clean or Contaminated? A Study on Bacterial Contamination in Splash Basins Used to Rinse Surgical Instruments During Surgery

Background: Preventing postoperative infection and promoting patient safety are essential responsibilities of the operating room nurse. In some hospitals, splash basins are used to rinse instruments during surgery, although previous studies emphasise the risk of bacterial contamination. A recent systematic review calls for further investigation into surgical teams' use of splash basins. Objectives: Our objective was to investigate bacterial contamination in splash basins and to identify the variables that may have an influence on this contamination. Methods: This prospective observational pilot study involved collecting, cultivating, and analysing water samples obtained from splash basins during operations performed in the thoracic and neurosurgical departments. The ventilation systems, length of surgery, number of instruments in the splash basin, number of persons present in the operating room, frequency of door openings during surgery, and type of bacteria were observed. Results: Bacterial growth was found in 44% of the final water samples: 41% from the thoracic surgical department, which had laminar airflow ventilation systems/unidirectional airflow ventilation, and 47% from the neurosurgical department, which had conventional ventilation systems/turbulent mixing ventilation. However, the binary logistic regression analysis revealed no significant correlation between bacterial growth and the ventilation systems, length of surgery, number of instruments in the splash basin, number of people in the operating room, or frequency of door openings. The most common types of bacteria found were coagulase-negative staphylococci and Micrococcus luteus. Conclusions: Splash basins become contaminated with bacteria during surgery. Therefore, using splash basins with sterile water is not recommended. Further research is needed to determine the best evidence-based practice for rinsing instruments perioperatively.

Facultatively Anaerobic Staphylococci Enable Anaerobic Cutibacterium Species to Grow and Form Biofilms Under Aerobic Conditions

Facultatively anaerobic Staphylococcus spp. and anaerobic Cutibacterium spp. are among the most prominent bacteria on human skin. Although skin microbes generally grow as multispecies biofilms, few studies have investigated the interaction between staphylococci and Cutibacterium spp. in dual-species biofilms. Here, we measured the mono- and dual-species biofilm formation of four staphylococcal species (S. epidermidis, S. hominis, S. capitis, and S. aureus) and two Cutibacterium spp. (C. acnes and C. avidum) cultured in vitro under both aerobic and anaerobic conditions. The biofilms were quantitated by rinsing them to remove planktonic cells, detaching the biofilm bacteria via sonication, and enumerating the cells by dilution plating. When cultured alone, staphylococci formed biofilms under both aerobic and anaerobic conditions, whereas Cutibacterium spp. formed biofilms only under anaerobic conditions. In co-culture, staphylococcal biofilm formation was unaffected by the presence of Cutibacterium spp., regardless of oxygen availability. However, Cutibacterium spp. biofilm formation was significantly enhanced in the presence of staphylococci, enabling robust growth under both anaerobic and aerobic conditions. Fluorescence confocal microscopy of the aerobic dual-species biofilms suggested that staphylococci create anaerobic niches at the base of the biofilm where C. acnes can grow. These findings demonstrate that staphylococci facilitate the colonization of Cutibacterium spp. in oxygen-rich environments, potentially explaining their presence in high numbers on the oxygen-exposed stratum corneum.

Catalase-positive Staphylococcus epidermidis based cryo-millineedle platform facilitates the photo-immunotherapy against colorectal cancer via hypoxia improvement

The synergistic anti-tumor impact of phototherapy and a cascading immune response are profoundly limited by hypoxia and a weakened immune response. Intravenous and intratumoral injection of therapeutic drugs also cause pain, rapid drug clearance and low utilization rates. Here, a novel cryo-millineedle platform for intratumoral delivery of a phototherapy system, S.epi@IR820, is developed in this work, combining the properties of Staphylococcus epidermidis (S. epidermidis) and IR820 for photo-immunotherapy of colorectal cancer. In this cryo-millineedle platform, S. epidermidis enhances the near-infrared absorption and light stability of IR820 and catalyzes the decomposition of H2O2 into O2 via an endogenous catalase to relieve tumor hypoxia, improve phototherapy and enhance immunogenic cell death (ICD). More interestingly, the native immunogenicity of S. epidermidis and ICD elicited by phototherapy achieved a potent anti-tumor immune response. To the best of our knowledge, this is the first study to utilize native S. epidermidis to relieve hypoxia and facilitate phototherapy. Both in vitro and in vivo experiments showed that the millineedle based phototherapy system can efficiently catalyse the decomposition of H2O2 into O2, facilitate phototherapeutic killing of CT26 tumor cells by S.epi@IR820 and enhance ICD, thus successfully activated the immune response and achieved the photo-immunotherapy against colorectal cancer. In conclusion, this study provides a novel strategy for enhanced anti-tumor efficiency of photo-immunotherapy, and develops an effective method for orthotopic administration of tumors.

Antimicrobial Resistance Profiles and mupA Gene Characterization of Staphylococcus epidermidis Recovered from Facial Skin of Healthy Females in Shanghai, China

Purpose

To explore antimicrobial resistance profiles and mupA gene characterization of Staphylococcus epidermidis recovered from facial skin of healthy females in Shanghai, China.

Patients and Methods

In this study, we collected facial skin samples from 107 healthy females in Shanghai, China, and S. epidermidis isolation was performed. The minimal inhibitory concentrations of 10 antibiotics were determined for the S. epidermidis isolates using the agar dilution method. High-level mupirocin-resistant isolates were subjected to whole-genome sequencing and bioinformatics analysis. A total of 94 un-duplicated S. epidermidis isolates were obtained from 107 facial skin samples.

Results

Antimicrobial susceptibility tests revealed that 23.4% of the 94 S. epidermidis isolates were resistant to oxacillin and positive for the mecA gene, which could be cauterized as methicillin-resistant S. epidermidis (MRSE). Resistance rates for erythromycin, clindamycin, tetracycline, ciprofloxacin, and gentamicin were 8.5%, 11.7%, 10.6%, 12.8%, and 1.1%, respectively. For mupirocin, the rates of low- and high-level resistance were 3.2% (3/94) and 11.7% (11/94), respectively. Resistance to vancomycin or linezolid was not observed. High-level mupirocin resistance in facial skin isolates is mediated by mupA. WGS and SNP-based phylogenetic analyses revealed diverse phylogenies among the 11 mupA-positive S. epidermidis isolates. Additionally, various resistance and virulence genes were identified in mupA-positive isolates. A new hybrid plasmid carrying mupA genes was found in two S. epidermidis isolates.

Conclusion

We observed a considerable level of antimicrobial resistance to several antibiotics and the prevalence of abundant and diverse resistance and virulence genes in the facial skin-origin S. epidermidis isolates. This may pose a potential risk for both public health and S. epidermidis infection.

The bacterial burden of worn face masks-observational research and literature review

Introduction

Facemasks were widely mandated during the recent SARS-CoV-2 pandemic. Especially the use by the general population is associated with a higher risk of improper handling of the mask and contamination and potential adverse microbiological consequences.

Methods

We investigated and quantified bacterial accumulation in facemasks used by the general population, using 16S rRNA (Sanger Sequencing), culture and biochemical analysis along with Rose Bengal staining. Additionally, a systematic overview of the literature on face mask contamination was undertaken.

Results

We found an average bacterial load of 4.24 × 104 CFU recovered/mask, with a maximum load of 2.85 × 105 CFU. This maximum is 310 times higher than the limit value for contamination of ventilation system outlet surfaces specified by the German standard VDI 6022. Biochemical and molecular identification predominantly found Staphylococcus species (80%), including Staphylococcus aureus, along with endospore-forming Bacillus spp. Literature reports also indicate contamination of masks by bacterial and fungal opportunists of the genera Acinetobacter, Aspergillus, Alternaria, Bacillus, Cadosporium, Candida, Escherichia, Enterobacter, Enterococcus, Klebsiella (including K. pneumoniae), Micrococcus, Microsporum, Mucor, Pseudomonas, Staphylococcus and Streptococcus. Bacterial counts increase linearly with wearing duration.

Discussion

Prolonged use may affect the skin and respiratory microbiomes, promoting consequential eye, skin, oral and airway conditions. These aspects underscore the urgent need for further research and a risk-benefit analysis in respect of mask use, particularly given their unproven efficacy in disrupting the transmission of respiratory viruses and their adverse social consequences.

The pathogenicity and virulence of the opportunistic pathogen Staphylococcus epidermidis

The pervasive presence of Staphylococcus epidermidis and other coagulase-negative staphylococci on the skin and mucous membranes has long underpinned a casual disregard for the infection risk that these organisms pose to vulnerable patients in healthcare settings. Prior to the recognition of biofilm as an important virulence determinant in S. epidermidis, isolation of this microorganism in diagnostic specimens was often overlooked as clinically insignificant with potential delays in diagnosis and onset of appropriate treatment, contributing to the establishment of chronic infection and increased morbidity or mortality. While impressive progress has been made in our understanding of biofilm mechanisms in this important opportunistic pathogen, research into other virulence determinants has lagged S. aureus. In this review, the broader virulence potential of S. epidermidis including biofilm, toxins, proteases, immune evasion strategies and antibiotic resistance mechanisms is surveyed, together with current and future approaches for improved therapeutic interventions.

Occurrence of Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus pseudintermedius colonization among veterinarians in the province of Malaga, Spain

Background and Aim

Staphylococcus pseudintermedius and Staphylococcus aureus are common colonizing pathogens in companion animals. These opportunistic pathogens can cause infections of varying frequency and severity in humans and pets. Studies on Staphylococcus colonization in veterinarians are scarce. This study aimed to investigate the colonization of the nostrils and hands by S. aureus, Staphylococcus epidermidis, and S. pseudintermedius among healthy clinical practice veterinarians in the province of Malaga (Spain), with a particular focus on their potential antibiotic resistance.

Materials and Methods

A request for voluntary participation was extended to professionals from the Official College of Veterinarians of Malaga. Nasal and hand swabs were collected by two trained technicians in January 2024, and all samples were delivered to the laboratory within 24 h. Gram staining, catalase, oxidase, and coagulase tests were performed. The susceptibility of the isolated bacteria to 11 antibiotics was evaluated.

Results

A total of 50 clinical practice veterinarians were enrolled in the study, comprising 36 women and 14 men from 31 veterinary clinics across Málaga province. A total of 32% of the nasal samples yielded S. aureus, whereas 64% were found to contain S. epidermidis. In total, 30% of the hand samples yielded S. aureus and 30% yielded S. epidermidis. The participants did not exhibit any strains of S. pseudintermedius in their nasal samples or hands. Two strains (11.1%) of methicillin-resistant S. aureus were isolated from 18 strains isolated from nostrils. Furthermore, a high prevalence of S. aureus strains resistant to ampicillin (94.4%) and amoxicillin (72.2%) was observed.

Conclusions

The colonization profiles of veterinary professionals were similar to those observed in the general population. Further research is required among veterinary professionals, companion animals, and their owners to better understand the colonization processes and the pet-human interface within a "One Health" approach.

Single-cell Sequencing of Circulating Human Plasmablasts during Staphylococcus aureus Bacteremia

Staphylococcus aureus is the major cause of healthcare-associated infections, including life-threatening conditions as bacteremia, endocarditis, and implant-associated infections. Despite adequate antibiotic treatment, the mortality of S. aureus bacteremia remains high. This calls for different strategies to treat this infection. In past years, sequencing of Ab repertoires from individuals previously exposed to a pathogen emerged as a successful method to discover novel therapeutic monoclonal Abs and understand circulating B cell diversity during infection. In this paper, we collected peripheral blood from 17 S. aureus bacteremia patients to study circulating plasmablast responses. Using single-cell transcriptome gene expression combined with sequencing of variable heavy and light Ig genes, we retrieved sequences from >400 plasmablasts revealing a high diversity with >300 unique variable heavy and light sequences. More than 200 variable sequences were synthesized to produce recombinant IgGs that were analyzed for binding to S. aureus whole bacterial cells. This revealed four novel monoclonal Abs that could specifically bind to the surface of S. aureus in the absence of Ig-binding surface SpA. Interestingly, three of four mAbs showed cross-reactivity with Staphylococcus epidermidis. Target identification revealed that the S. aureus-specific mAb BC153 targets wall teichoic acid, whereas cross-reactive mAbs BC019, BC020, and BC021 target lipoteichoic acid. All mAbs could induce Fc-dependent phagocytosis of staphylococci by human neutrophils. Altogether, we characterize the active B cell responses to S. aureus in infected patients and identify four functional mAbs against the S. aureus surface, of which three cross-react with S. epidermidis.

Investigations on the surface disinfection efficacy of far-UVC 222 nm germicidal irradiance device in a controlled environment and field test

The Covid 19 pandemic has significantly affected the health, economy, and social impact of humanity. The continuous mutations of the virus variants have accelerated the demand for scientific research on disinfection techniques for a safer indoor environment. Among all the available surface disinfection techniques, ultraviolet germicidal irradiance at 254 nm wavelength has been proven for its disinfection efficacy; however, its usage is limited to unoccupied conditions due to the risk of ultraviolet exposure. This study investigated the efficacy of far-UVC-222 nm experimentally in both controlled environment and field setting. Staphylococcus epidermidis and Mycobacterium smegmatis were employed for surface disinfection in both the laboratory and a meeting room. Total plate count was used to determine the disinfection efficacy by a 20 W unfiltered far-UVC lamp. At 1.1 µW/cm2 far-UVC irradiation, a 1-log10 reduction of Staphylococcus epidermidis and Mycobacterium smegmatis contamination on tabletop can be achieved by 31.3 min and 101.8 min of far-UVC irradiation, respectively. Other pathogens of interest such as Staphylococcus aureus, Mycobacterium tuberculosis, Legionella pneumophila, SARS-CoV-2, and the Measles virus were also referred and compared in this study. This study carefully examined how far-UVC irradiation performs effectively for surface disinfection in a real meeting room setting. The results offer useful recommendations for alternatives to upper-room ultraviolet germicidal irradiance for continuous disinfection within the ultraviolet threshold limit value, with the goal of preventing the spread of any diseases in the future.

Microbial diversity analysis and isolation of thermoresistant lactic acid bacteria in pasteurized milk

Pasteurization is a common method for dairy products, typically heating at 72 °C for 15 s or 63 °C for 30 min. The 17 samples of commercial pasteurized milk were divided into three groups according to the shelf life: group A (1-5 days), group B (6-10 days) and group C (11-15 days), and the diversity composition of microbial communities in the samples was analyzed. Among all groups, Proteobacteria, Firmicutes, and Bacteroidetes were the dominant bacterial phyla. The lactic acid bacteria (LAB) were mostly Streptococcus, Weissella and Lactobacillus, and there were high proportions of Streptococcus thermophilus in group A, Weissella paramesenteroides in group B, and Lactobacillus plantarum in group C. Furthermore, a strain of Enterococcus faecium SFM2 was isolated from the A2 sample, which showed better temperature tolerance compared to the E. faecium SFM1 of oral origin. After treatment at 50 °C for 2 h, the survival rates of E. faecium SFM1 and SFM2 were 28.20 ± 0.04% and 82.58 ± 0.01%, respectively. This study investigated the diversity of microorganisms in pasteurized milk, providing effective information for analyzing the potential microbiota of commercial pasteurized milk. Meanwhile, it provided new ideas for expanding the resource pool of thermoresistant LAB.