There is an increasing need for new treatment regimens to combat antibiotic-resistant strains of bacteria. Staphylococcus aureus is a clinically important, opportunist pathogen that has developed resistance to a range of antibiotics. The zebrafish larval model of systemic disease has been increasingly utilized to elucidate S. aureus virulence mechanisms and host-pathogen interactions. Here, we outline how this model can be used to investigate the effects of different antibiotics alone and in combination against S. aureus.

Patients with chronic limb-threatening ischaemia (CLTI) are at risk of foot infections, which is associated with an increase in amputation rates. The use of antibiotics may lead to a higher incidence of antimicrobial resistance (AMR) in subsequent episodes of ischaemic foot infections (IFI). This retrospective single-centre cohort study included 130 patients with IFI undergoing endovascular revascularisation. Staphylococcus aureus and Pseudomonas aeruginosa were the two most common pathogens, accounting for 20.5% and 10.8% of cases, respectively. The prevalence of antimicrobial resistance (AMR) and multi-drug resistance did not significantly increase between episodes (10.2% vs. 13.4%, p = 0.42). In 59% of subsequent episodes, the identified pathogens were unrelated to the previous episode. However, the partial concordance of identified pathogens significantly increased to 66.7% when S. aureus was identified (p = 0.027). Subsequent episodes of IFI in the same patient are likely to differ in causative pathogens. However, in the case of S. aureus, the risk of reinfection, particularly with S. aureus, is increased. Multi-drug resistance does not appear to change between IFI episodes. Therefore, recommendations for empirical antimicrobial therapy should be based on local pathogen and resistance statistics without the need to broaden the spectrum of antibiotics in subsequent episodes.

Broad-spectrum antibacterial drugs often lack specificity, leading to indiscriminate bactericidal activity, which can disrupt the normal microbial balance of the host flora and cause unnecessary cytotoxicity during systemic administration. In this study, we constructed a specifically targeted antimicrobial peptide against Staphylococcus aureus by introducing a phage-displayed peptide onto a broad-spectrum antimicrobial peptide and explored its structure-function relationship through one-factor modification. SFK2 obtained by screening based on the selectivity index and the targeting index showed specific killing ability against S. aureus. Moreover, SFK2 showed excellent biocompatibility in mice and piglet, and demonstrated significant therapeutic efficacy against S. aureus infection. In conclusion, our screening of phage-derived heptapeptides effectively enhances the specific bactericidal ability of the antimicrobial peptides against S. aureus, providing a theoretical basis for developing targeted antimicrobial peptides.

Handwashing represents an important personal hygiene measure for preventing infection. Herein, we report the persistence of antibacterial and antiviral effects after handwashing with fatty acid salt-based hand soap. To this end, we developed a new in vitro test method to measure persistence, utilizing coacervation formed by anionic surfactants and cationic polymers to retain highly effective soap components against each bacterium and virus on the skin. Coacervation with fatty acid salts and poly diallyldimethylammonium chloride (PDADMAC) as a cationic polymer allowed the persistence of antibacterial and antiviral effects against E. coli, S. aureus, and influenza virus even 4 h after handwashing. Furthermore, we confirmed an increase in the number of residual components effective against each bacterium and virus on the skin. In summary, the current findings describe an effective approach for enhancing the protective effects of handwashing.

BACKGROUND: Chronic leg ulcers are hard to treat and can be a burden, particularly in resource-limited settings where diagnosis is a challenge. Staphylococcus aureus is among the common bacteria isolated from chronic wounds with a great impact on wound healing, particularly in patients with co-morbidities. Antimicrobial resistance genes and virulence factors in Staphylococcus aureus isolates were assessed to support healthcare professionals to make better therapeutic choices, and importantly to curb the development and spread of antibiotic resistance.
METHODS: A cross-sectional study involved both inpatients and outpatients with chronic leg ulcers was conducted from August 2022 to April 2023 in 2 health facilities in Kilimanjaro region in Tanzania. Antimicrobial susceptibility testing was done using the disc diffusion method. Further, whole genome sequencing was performed to study the genotypic characteristics of the isolates.
RESULTS: A total of 92 participants were recruited in which 9 participants were only positive for 10 Staphylococcus aureus isolates upon culture. Five STs among 9 isolates were identified. Most of them belonged to ST8 (44%), with 1 isolate does not belong to any ST. Additionally, 50% of the isolates were methicillin-resistant Staphylococcus aureus (MRSA). All S. aureus isolates had almost similar virulence factors such as hemolysin, proteases and evasions that promote toxin production, protease production and host immune evasion respectively. Moreover, all mecA positive S. aureus isolates were phenotypically susceptible to cefoxitin.
CONCLUSIONS: Presence of mecA positive S. aureus isolates which are also phenotypically susceptible to cefoxitin implies the possibility of classifying MRSA as MSSA. This may result in the possible emergence of highly cefoxitin - resistant strains in health care and community settings when subsequently exposed to beta-lactam agents. Therefore, combination of whole genome sequencing and conventional methods is important in assessing bacterial resistance and virulence to improve management of patients.

Antibiotics\' usefulness is threatened by multi-drugs resistance in harmful microorganisms because of abuse and regulatory problems. Emerging microbes, resistance mechanisms and antimicrobial drugs all require extensive investigation. Evaluation of the in vitro antibacterial activity of Methanolic extracts isolated from Black pepper seeds (Piper nigrum L.) against two infection causing pathogens, Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa. From July 2022 and June 2023, this experimental study was conducted at the Mymensingh Medical College\'s Department of Pharmacology and Therapeutics in conjunction with the Department of Microbiology. The solvents Methanol and 10.0% Di-Methyl Sulfoxide (DMSO) were used to make the extract. Using the disc diffusion and broth dilution methods, the antibacterial activity of methanolic extract of black pepper seeds (MBPE) was evaluated at various doses. Using the broth dilution procedure, the conventional antibiotic Ciprofloxacin was utilized, and the outcome was contrasted with that of Methanol extracts. Methanolic extract of black pepper seeds (MBPE) at seven distinct concentrations (100, 80, 60, 40, 20, 10 and 5mg/ml) were utilized, then later in chosen concentrations as needed to confirm the extracts\' more precise margin of antimicrobial sensitivity. At 80mg/ml and above doses of the MBPE, it had an inhibitory impact against the aforementioned microorganisms. For Staphylococcus aureus and Pseudomonas aeruginosa the MIC were 60 and 70mg/ml in MBPE respectively. As of the MIC of Ciprofloxacin was 1μg/ml against Staphylococcus aureus and 1.5μg/ml for Pseudomonas aeruginosa. In comparison to MICs of MBPE for the test organisms, the MIC of Ciprofloxacin was the lowest. This study clearly shows that Staphylococcus aureus and Pseudomonas aeruginosa are sensitive to the methanolic extract of black pepper seeds\' antibacterial properties.

UNASSIGNED: The formation of biofilms, characterized by cell aggregation and extracellular polymeric substance (EPS) production, is a common feature of periprosthetic joint infections (PJI).
UNASSIGNED: The current study aimed to investigate the development of biofilm features in vitro within less than 3 weeks by Staphylococcus aureus isolated from PJIs.
UNASSIGNED: Biofilms were grown on sandblasted titanium discs, and fluorescence spectroscopy and microscopy were used to observe biofilm maturation for 21 days.
UNASSIGNED: DNA mass decreased initially, then increased from day 5 onwards, and decreased again after day 7. The proportion of living to dead bacteria oscillated until day 7 and increased at day 10 for strain A and day 14 for strain B. EPS mass decreased initially and then continuously increased. Multilayer bacterial organization was observed at day 7.
UNASSIGNED: Cell aggregation occurred during the first week, followed by EPS production in the second week, and characteristic biofilm features were observed within 1 to 2 weeks.

The engineering of a home-made portable double-layer filtration and concentration device with the common syringe for rapid analysis of water samples is reported. The core elements of the device were two installed filtration membranes with different pore sizes for respective functions. The upper filtration membrane was used for preliminary intercepting large interfering impurities (interception membrane), while the lower filtration membrane was used for collecting multiple target pathogens (enrichment membrane) for determination. This combination can make the contaminated environmental water, exemplified by surface water, filtrated quickly through the device and just retained the target bacteria of Escherichia coli O157:H7, Staphylococcus aureus, and Listeria monocytogenes on the lower enrichment membrane. Integrating with surface-enhanced Raman spectra (SERS) platform to decode the SERS-Tags (SERS-TagCVa, SERS-TagR6G, and SERS-TagMB) already labeled on each of the enriched bacteria based the antibody-mediated immuno-recognition effect, fast separation, concentration, and detection of multiple pathogenic bacteria from the bulk of contaminated environmental water were realized. Results show that within 30 min, all target bacteria in the lake water can be simultaneously and accurately measured in the range from 101 to 106 CFU mL-1 with detection limit of 10.0 CFU mL-1 without any pre-culture procedures. This work highlights the simplicity, rapidness, cheapness, selectivity, and the robustness of the constructed method for simultaneous detecting multiple pathogens in aqueous samples. This protocol opens a new avenue for facilitating the development of versatile analytical tools for drinking water and food safety monitoring in underdeveloped or developing countries.

The aim of this prospective pilot study was to compare culture and microbiome results of the removed tonsils of patients with assumed distant focal disease (11 patients) and those who underwent a tonsillectomy, due to other reasons, such as recurrent tonsillitis, tonsil stones or snoring (nine patients). Aerobic culture was carried out for samples taken from the surface of the tonsils by swabs before tonsillectomy for all 20 patients. The squeezed detritus and the tissue samples of removed tonsils, taken separately for the right and left tonsils, were incubated aerobically and anaerobically. The microbiome composition of tissue samples of removed tonsils was also evaluated. Based on the culture results of the deep samples Staphylococcus aureus was the dominating pathogen, besides a great variety of anaerobic and facultative anaerobic bacteria present in the oral microbiota in those patients who underwent tonsillectomy due to distant focal diseases. Microbiome study of the core tissue samples showed a great diversity on genus and species level among patients of the two groups however, S. aureus and Prevotella nigrescens were present in higher proportion in those, whose tonsils were removed due to distant focal diseases. Our results may support previous findings about the possible triggering role of S. aureus and P. nigrescens leading to distant focal diseases. Samples taken by squeezing the tonsils could give more information about the possible pathogenic/triggering bacteria than the surface samples cultured only aerobically.

Garlic (Allium sativum L.), particularly its volatile essential oil, is widely recognized for medicinal properties. We have evaluated the efficacy of Indian Garlic Essential Oil (GEO) for antimicrobial and antibiofilm activity and its bioactive constituents. Allyl sulfur-rich compounds were identified as predominant phytochemicals in GEO, constituting 96.51% of total volatile oils, with 38% Diallyl trisulphide (DTS) as most abundant. GEO exhibited significant antibacterial activity against eleven bacteria, including three drug-resistant strains with minimum inhibitory concentrations (MICs) ranging from 78 to 1250 µg/mL. In bacterial growth kinetic assay GEO effectively inhibited growth of all tested strains at its ½ MIC. Antibiofilm activity was evident against two important human pathogens, S. aureus and P. aeruginosa. Mechanistic studies demonstrated that GEO disrupts bacterial cell membranes, leading to the release of nucleic acids, proteins, and reactive oxygen species. Additionally, GEO demonstrated potent antioxidant activity at IC50 31.18 mg/mL, while its isolated constituents, Diallyl disulphide (DDS) and Diallyl trisulphide (DTS), showed effective antibacterial activity ranging from 125 to 500 µg/mL and 250-1000 µg/mL respectively. Overall, GEO displayed promising antimicrobial and antibiofilm activity against enteric bacteria, suggesting its potential application in the food industry.