Evaluation of a Rhodomyrtus tomentosa ethanolic extract for its therapeutic potential on Staphylococcus aureus infections using in vitro and in vivo models of mastitis.

An ethanolic extract from Rhodomyrtus tomentosa leaves (RTL) was studied as a natural alternative to control Staphylococcus aureus, which is an important pathogen responsible for bovine mastitis. The minimal inhibitory concentrations (MICs) of the RTL extract and of rhodomyrtone, a pure compound isolated from the plant, were determined by a microdilution method. Rhodomyrtone and the RTL extract exhibited antibacterial activity against S. aureus, including its persistent phenotype (SCV: small-colony variant) and a biofilm hyperproducer strain, with MICs of 0.25-0.5 and 8-16 µg/mL, respectively. Time-kill kinetics showed a strong bactericidal activity for both the RTL extract- and rhodomyrtone-treated bacteria at 2 × MIC as early as 4 h post-exposure. An additive effect of the extract at 0.5 × MIC was observed in a combination with oxytetracycline or pirlimycin against S. aureus by showing a 64- to 128-fold reduction in antibiotic MICs. Moreover, the RTL extract significantly decreased the number of intracellular SCVs inside bovine mammary epithelial cells. However, the extract or its combination with pirlimycin only slightly improved the activity of pirlimycin against the bacterial colonization of mouse mammary glands. In vitro MICs determined in the presence of casein indicated that the limited activity of the RTL extract in the murine model of mastitis could be linked to neutralization of active components by milk proteins. While the RTL extract showed interesting antibacterial properties in vitro, to be considered as an alternative to antibiotics in dairy farms, formulation studies are needed to cope with the observed reduction of activity in vivo.

Chicago sky blue gel for better visualization of Demodex in patients with Demodex blepharitis.

Background: Demodex blepharitis is a common chronic disease. The number of mites is associated with ocular discomfort. The accurate number derived from well-stained specimens is, hence, in favor of diagnosing, monitoring, and determining treatment responses. Methods: A cross-sectional study was conducted between April and July 2022 at the dermatology and ophthalmology clinic, Walailak University, Thailand. Adult participants with clinical suspicion of Demodex blepharitis were recruited. We examined eyelashes under light microscopy to quantify the number of Demodex mites before and after adding CSB gel. The mite counts, evaluated by an untrained investigator and an experienced investigator, were recorded and compared. Results: A total of 30 participants were included for final analysis, among which 25 (83.3%) were female. The median age was 64.0 years (IQR, 61.0-68.0). The median Demodex counts evaluated by the experienced investigator before and after adding CSB gel were 1.0 (IQR, 0.0-1.0) and 2.5 (IQR, 2.0-3.0), respectively (p < 0.001). Moreover, the median Demodex counts evaluated by the untrained investigator before and after adding CSB gel were 1.0 (IQR, 0.0-1.0) and 2.0 (IQR, 1.0-3.0), respectively (p < 0.001). The correlation coefficient between Demodex counts after the addition of CSB counted by the experienced investigator and those counted by the untrained investigator was 0.92 (p < 0.001). CSB gel is a promising product to identify and quantify the number of Demodex mites. The findings supported the consideration of CSB gel as one of the diagnostic stains.

The potency of herbal extracts and its green synthesized nanoparticle formulation as antibacterial agents against Streptococcus mutans associated biofilms.

This study aims to determine the effects of the extracts of Streblus asper, Cymbopogon citratus, Syzygium aromaticum and its formulation of green synthesized silver nanoparticle (AgNPs) on Streptococcus mutans growth and biofilm formation. The ethanolic extracts of S. asper, C. citratus, S. aromaticum, and a mix of the three herbs demonstrated antibacterial activity against S. mutans isolates by reducing bacterial biofilm formation and decreasing bacterial cell surface hydrophobicity. The formulated AgNPs from the ethanolic extracts could enhance the antibacterial activities of the plant extracts. Molecular docking found the best interaction between luteolin isolated from C. citratus and glucosyltransferase protein (GtfB), assuming the promising anti-biofilm activity. The scanning electron microscopy revealed morphological changes in the biofilm structure and a significant decrease in the biofilm area of the AgNPs treated. The study suggested that the extracts and its application could be used as natural alternative agents with multi-action against S. mutans infections.

Effectiveness of an online educational video intervention to improve the knowledge and behavior of contact lens care during the COVID-19 pandemic: A pre-test/post-test design.

Objective: To assess the effectiveness of an online educational video in improving contact lens (CL) care knowledge and behavior. Methods: Participants completed a 47-item questionnaire on their CL hygiene knowledge and wear and care behavior. A 5-min CL educational video was shown, and participants completed a post-test. After 2 months, the same questionnaire was used to determine knowledge retention and behavioral changes. Descriptive statistics and McNemar's tests were performed. Results: The mean age of the 132 enrolled participants was 24 years, and 61% were female. The knowledge scores significantly improved after watching the educational video (p < 0.001). Two months after the intervention, the participants reported changes in their hygienic behavior (p < 0.001). Conclusions: Online video-based learning is an effective educational tool for improving the knowledge and behavior of CL care. Practice implications: Patient education via online videos is an innovative and successful strategy that raises awareness, increases patient knowledge, and encourages preventative health behavior to avoid CL-related complications.

Rub and Rinse Contact Lenses Before Wearing as a Protective Regimen Against Contact Lens-Related Eye Infections.

Purpose: Data on contact lens (CL) users in Thailand are limited, and previous reports have mainly focused on young populations. This study aims to determine demographic data, hygienic behaviour, and complications related to the usage of CLs in the general population. Methods: This was a cross-sectional survey conducted from November 2020 to March 2021 using an anonymous questionnaire. Information on the demographic traits of the participants, characteristics of CL use, and CL care behaviours was collected. The responses were summarised and presented as a total behaviour score. Regression analysis was performed to evaluate the potential risk factors for a history of CL-related eye infections. Results: A total of 134 CL wearers were recruited. Of all the participants, 83.58% were female and 16.42% were male. The average age was 31.14±10.69 years old. The total behaviour score showed that 62.69% of the population had good CL behaviour, while 37.31% exhibited poor CL behaviour. More than 50% of participants practised appropriate CL handling. Common unfavourable behaviours (>50%) reported were not using CL care solution to clean the storage case, not rubbing and rinsing the lens before storage, exposure to water during wear, use of makeup around the ocular area, and missing annual eye exams. Other less common but important instances of mishandling included using tap water to clean the lenses, topping off old CL solution, and exceeding the recommended planned-replacement period. However, no behaviours were significantly associated with a history of CL-related eye infections. Rubbing and rinsing CLs before wearing them was found to be a protective factor against a history of eye infections. Conclusion: Rubbing and rinsing CLs before wearing should be mentioned as an additional recommendation for the user.

Bacterial microbiota of the contact lens surface and associated care behaviours.

Introduction: Contact lens (CL) wear has been reported to cause changes to the microbiome of the ocular surface. More insight into the alteration of this microenvironment can help to understand the pathogenesis of CL-related eye infections. Knowledge of the relationship between the CL wearer's behaviours and pathogens would help health care providers focus on each step of proper CL care. This study aims to determine the behaviours that might be associated with the community of bacteria on CL. Methods: A cross-sectional design was performed using anonymous questionnaires to obtain demographic data and assess hygiene practices among volunteering wearers. The CLs used were collected to evaluate the prevalence of pathogenic bacteria associated with ocular infections by PCR and microbiota analysis. Results: The bacterial microbiota study revealed a total of 19 genera and 26 isolated strains from 20 eligible CLs. Enterobacter, Staphylococcus, and Achromobacter were the main genus in this subject population. Staphylococcus pasteuri and Achromobacter agilis were the most common pathogens at 65% and 35%, respectively. Enterobacter mori, a nonpathogenic organism, was found to be the most predominant strain, accounting for 27.51% of the total bacterial constituents. The risk behaviour of CL wear that was significantly associated with A. agilis contamination was cleaning the CL case with tap water (P value = 0.04). Conclusions: This is the first study focusing on the association between the culture selected microbial community on the CL surface and compehensive behavioural characteristics. Environmental contamination was the main source of microbes found on CL surfaces. An emphasis in patient education should be placed on careful handling during the CL care routine and managing the hygiene of the surroundings.

Influence of Contact Lens Materials and Cleaning Procedures on Bacterial Adhesion and Biofilm Formation.

PURPOSE: The present study aimed to compare the existing soft contact lens (CL) materials regarding their influence on bacterial biofilm formation and adhesion susceptibility. Then, the study was designed to investigate the effectiveness of various disinfecting solutions and evaluate the ability of cleaning regimens in terms of anti-bacterial adhesion and biofilm removal on different soft CL materials. METHODS: Bacterial biofilm formation on CLs was evaluated by biomass assay. Adhesion assay and standard plate count were carried out at time-interval periods within 24 h. Various CL disinfecting procedures were assessed for their efficacy to remove biofilm and reduce bacterial adhesion. Scanning electron microscopy (SEM) was performed for the morphological assessment of bacterial biofilm. RESULTS: Printed hydroxyethyl methacrylate (HEMA) CLs significantly demonstrated more biofilm staining and bacterial attachment when compared with non-printed HEMA CLs, while the Filcon II 3 and Nesofilcon A CLs possessed less biofilm biomass and adherent cells. Staphylococcus aureus and Pseudomonas aeruginosa represented the highest biofilm producing bacteria on HEMA-based materials in this study. The disinfecting regimen with the highest efficacy was the two-step system, first using multipurpose disinfecting solution containing edetate disodium and sorbic acid (MPDS+EDSA), followed by soaking in multipurpose solution (MPS). The regimen demonstrated the greatest effect against the pre-formed biofilm and the adhesion activity of S. aureus and P. aeruginosa on the soft CLs. The SEM micrographs confirmed the morphological changes of bacterial biofilm after disinfecting and revealed that the two-step system treated CLs displayed less adherent bacteria. CONCLUSION: HEMA-based soft CLs may facilitate bacterial biofilm formation and adhesion capability. The two-step system was the most effective regimen for biofilm removal, where the soaking period in the disinfecting solution of the no-rub regimen should last more than 6 h to remove pre-formed biofilm.

Rhodomyrtus tomentosa (Aiton) Hassk. leaf extract: An alternative approach for the treatment of staphylococcal bovine mastitis.

Antibiotic residues in dairy products as well as emergence of antimicrobial resistance in foodborne pathogens have been recognized as global public health concerns. The present work was aimed to study a potent antibacterial extract from natural product as an alternative treatment for staphylococcal bovine mastitis. Staphylococcal isolates (n=44) were isolated from milk samples freshly squeezed from individual cows. All staphylococcal isolates were resistant to ampicillin, ciprofloxacin, erythromycin, gentamicin, penicillin, except vancomycin. Rhodomyrtus tomentosa leaf ethanolic extract was accessed for its antibacterial activity and anti-inflammatory potential. The extract exhibited profound antibacterial activity against all of staphylococcal isolates with MIC and MBC values ranged from 16-64 µg/ml and 64->128 µg/ml, respectively. Moreover, the extract also exerted anti-protein denaturation and human red blood cell membrane stabilizing activity. The results support the use of R. tomentosa extract that could be applied to cure bovine mastitis and to reduce inflammatory injury caused by the bacterial infections.

Effects of Rhodomyrtus tomentosa Leaf Extract on Staphylococcal Adhesion and Invasion in Bovine Udder Epidermal Tissue Model.

Bovine mastitis is one of the most important infectious diseases in dairy herds, and staphylococci are the most important etiologic agents of this disease. Antibiotics and chemical agents used in livestock for prevention and cure of the disease can accumulate in milk and give rise to food safety concerns. Rhodomyrtus tomentosa leaf extract was studied as an alternative approach to reduce the bacterial infections. The ethanolic extract of this plant demonstrated antibacterial activity with minimum inhibitory concentration (MIC) values as low as 16-64 µg/mL against staphylococcal isolates. In addition, the extract had an effect on the bacterial cell surface properties by increasing its hydrophobicity in a concentration dependent manner. To further extend the antibacterial efficacy, silver nanoparticles synthesized with the extract, a pure rhodomyrtone, and liposomal encapsulated rhodomyrtone were applied and their inhibitory effects on bacterial adhesion and invasion were determined by ex vivo study in a bovine udder epidermal tissue model. These agents exerted remarkable antibacterial activity against staphylococci and decreased the adhesion of the bacterial cells to the tissues. These results supported that R. tomentosa ethanolic extract could be applied as an alternative agent for bovine udder care in dairy farms.