Staphylococcus aureus

Sustainable Antimicrobial and Anticancer Agents: Eco-Friendly Synthesis of Copper Nanoparticles Using Biebersteinia multifida DC

Biebersteinia multifida DC. is a wild therapeutic plant, traditionally used for various medicinal applications. The aim of the present study is to extract bioactive constituents from the plants' roots and synthesize copper nanoparticles (CuNPs). Ethanolic extraction of the plant's roots yielded 19 bioactive compounds, recognized through gas chromatography-mass spectroscopy (GC-MS), mainly including citraconic anhydride, γ-sitosterol, and 2-furancarboxaldehyde. The prepared CuNPs have been fully characterized. The biological activity evaluations revealed these CuNPs possess acceptable antibacterial and antifungal activities. Furthermore, the CuNPs displayed significant cytotoxic potency toward "4T1 breast cancer cells" while showing a relatively low cell death rate against the normal "HEK-293 kidney cell". In conclusion, our findings showed that the CuNPs can be synthesized from B. multifida roots with a simple, fast, and eco-friendly procedure. These CuNPs are efficient in antimicrobial and anticancer activities.

Frog-derived synthetic peptides display anti-infective activity against Gram-negative pathogens

Novel antibiotics are urgently needed since bacteria are becoming increasingly resistant to existing antimicrobial drugs. Furthermore, available antibiotics are broad spectrum, often causing off-target effects on host cells and the beneficial microbiome. To overcome these limitations, we used structure-guided design to generate synthetic peptides derived from Andersonin-D1, an antimicrobial peptide (AMP) produced by the odorous frog Odorrana andersonii. We found that both hydrophobicity and net charge were critical for its bioactivity, enabling the design of novel, optimized synthetic peptides. These peptides selectively targeted Gram-negative pathogens in single cultures and complex microbial consortia, showed no off-target effects on human cells or beneficial gut microbes, and did not select for bacterial resistance. Notably, they also exhibited in vivo activity in two preclinical murine models. Overall, we present synthetic peptides that selectively target pathogenic infections and offer promising preclinical antibiotic candidates.

Microbiological Analysis Conducted on Raw Milk Collected During Official Sampling in Liguria (North-West Italy) over a Ten-Year Period (2014-2023)

Milk has been consumed by humans for thousands of years for its nutritional properties. In recent years, raw milk demand has increased, valued for its authenticity and connection to local traditions. In Italy, the sale of raw milk is allowed exclusively through direct sale from the producing farm to the final consumer, either at the producing farm itself or through vending machines. However, the consumption of raw milk is not without risks. Among these, microbiological ones are relevant. These can lead to severe symptoms, particularly in vulnerable populations. For this reason, although consumers are advised to boil raw milk before consumption, producing farms in Italy are required to meet the microbiological criteria outlined in the Provision of 25 January 2007. In this retrospective study, the results of the analyses performed on 355 raw milk samples collected in Liguria between 2014 and 2023 for the detection of Campylobacter spp., Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli O157 were analysed to better characterise the associated risk for consumers. The samples were collected during official controls by the local veterinary health services at vending machines of seven producing farms. Overall, six samples tested positive for C. jejuni, while only one sample tested positive for Salmonella enterica subsp. enterica, Serovar Veneziana. Listeria monocytogenes, S. aureus, and E. coli O157 were never responsible for non-compliances. Interestingly, three of the six samples positive for C. jejuni derived from the same producer. In farms where positive samples were detected, certain structural and/or operational non-compliances were identified. It can be concluded that, although the scenario in question does not present any cause for concern, it is nevertheless essential to implement a series of preventive measures in order to guarantee the safety of raw milk. These measures include the implementation of biosecurity practices, the maintenance of strict hygiene protocols during milking, and the adherence to the cold chain distribution protocol until the final stage of distribution.

Antimicrobial Activity of Euphorbia helioscopia L. Against Methicillin-Resistant Staphylococcus aureus (MRSA) In Vitro

BACKGROUND

Antimicrobial resistance is currently one of the most significant threats to medical science, necessitating the exploration of new antimicrobial agents. Methicillin-resistant Staphylococcus aureus (MRSA) can lead to various severe conditions such as endocarditis, meningitis, abscesses, and sepsis, and conventional antibiotics such as beta-lactams are ineffective for treating these diseases. Therefore, it is imperative to search for novel chemical substances with antimicrobial effects against MRSA. This study aimed to investigate the bioactive chemical compound extracts isolated from Euphorbia helioscopia L. plant material against clinical samples of MRSA collected from the Hospital of Lithuanian University of Health Sciences Kaunas Clinics.  Methodology: Bioactive compounds from the aboveground parts of Euphorbia helioscopia L. were isolated using methanol extraction of herbal material followed by lyophilization. The total phenolic compound concentration was determined using the Folin-Ciocalteu method. Antioxidant power was assessed through the ferric reducing antioxidant power (FRAP) assay, chemical composition was analyzed via high-performance liquid chromatography (HPLC), and antimicrobial activity against MRSA was evaluated using the disc diffusion method.

RESULTS

 The lyophilized extract of Euphorbia helioscopia L. exhibited antimicrobial activity against two out of five strains of MRSA. Seven phenolic compounds were identified, three of which were not previously reported as constituents of Euphorbia helioscopia L. More than a third of the isolated compounds were phenolic compounds.  Conclusion: Euphorbia helioscopia L. exhibits antimicrobial properties effective against certain strains of MRSA.

Evaluating the pharmacological activities of Aloe perryi-Silver nanoparticles induced apoptosis against colon cancer cells (HCT-116)

Aloe perryi has been studied and possesses several activities, including antibacterial, antiparasitic, and anticancer properties. In this study, A. perryi was used as a reducing agent of silver ions into silver nanoparticles. Aloe perryi-silver nanoparticles (APS-NPs) were characterized and evaluated using characterization techniques. However, the antioxidative, antibacterial, and anticancer assays were studied to evaluate the pharmacological activities of APS-NPs. APS-NPs were developed and changed to dark brown and the maximum absorption was 442 nm. SEM (5-583 nm), TEM (4-110 nm), XRD (21.84 nm), and zeta potential analysis (63.39 nm) revealed that the APS-NPs were nano-sized, and the APS-NPs had a cubic crystalline structure, according to the XRD results. FTIR analysis suggested that functional groups of A. perryi metabolites were involved in forming APS-NPs. The zeta potential indicated that the APS-NPs were negatively charged (-32 mV), suggesting good stability. APS-NPs showed significant antioxidative stress activity by reducing DPPH-free radicles in a dose-dependent manner. APS-NPs-induced antibacterial effect against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and Acinetobacter baumannii (A. baumannii). APS-NPs reduced the cell viability and cell migration of the human colon tumor cell line (HCT 116) compared with controls, indicating that APS-NPs could play a role in reducing metastasis and inducing cell apoptosis against colon cancer. In conclusion, the nanoparticle synthesis from A. perryi extract demonstrated excellent antioxidant, antibacterial, and anticancer activities, thus suggesting that our APS-NPs have the potential to be used as antioxidative and antibacterial in food and pharmaceutical industries.

Surface Topography, Microbial Adhesion, and Immune Responses in Silicone Mammary Implant-Associated Capsular Fibrosis

Breast cancer is the most common cancer in women globally, often necessitating mastectomy and subsequent breast reconstruction. Silicone mammary implants (SMIs) play a pivotal role in breast reconstruction, yet their interaction with the host immune system and microbiome remains poorly understood. This study investigates the impact of SMI surface topography on host antimicrobial responses, wound proteome dynamics, and microbial colonization. Biological samples were collected from ten human patients undergoing breast reconstruction with SMIs. Mass spectrometry profiles were analyzed for acute and chronic wound proteomes, revealing a nuanced interplay between topography and antimicrobial response proteins. 16S rRNA sequencing assessed microbiome dynamics, unveiling topography-specific variations in microbial composition. Surface topography alterations influenced wound proteome composition. Microbiome analysis revealed heightened diversity around rougher SMIs, emphasizing topography-dependent microbial invasion. In vitro experiments confirmed staphylococcal adhesion, growth, and biofilm formation on SMI surfaces, with increased texture correlating positively with bacterial colonization. This comprehensive investigation highlights the intricate interplay between SMI topography, wound proteome dynamics, and microbial transmission. The findings contribute to understanding host-microbe interactions on SMI surfaces, essential for optimizing clinical applications and minimizing complications in breast reconstruction.

Biofilm formation of two genetically diverse Staphylococcus aureus isolates under beta-lactam antibiotics

PURPOSE

Our aim was to evaluate the biofilm formation of 2 genetically diverse Staphylococcus aureus isolates, 10379 and 121940, under different concentrations of beta-lactam antibiotics on biomass content and biofilm viability.

METHODS

Biofilm formation and methicillin resistance genes were tested using PCR and multiplex PCR. PCR was combined with bioinformatics analysis to detect multilocal sequence typing (MLST) and SCCmec types, to study the genetical correlation between the tested strains. Then, the crystal violet (CV) test and XTT were used to detect biomass content and biofilm activity. Antibiotic susceptibility was tested using a broth dilution method. According to their specific MIC, different concentrations of beta-lactam antibiotics were used to study its effect on biomass content and biofilm viability.

RESULTS

Strain 10379 carried the icaD, icaBC, and MRSA genes, not the icaA, atl, app, and agr genes, and MLST and SCCmec typing was ST45 and IV, respectively. Strain 121940 carried the icaA, icaD, icaBC, atl, and agr genes, not the aap gene, and MLST and SCCmec typed as ST546 and IV, respectively. This suggested that strains 10379 and 121940 were genotypically very different. Two S. aureus isolates, 10379 and 121940, showed resistance to beta-lactam antibiotics, penicillin, ampicillin, meropenem, streptomycin and kanamycin, some of which promoted the formation of biofilm and biofilm viability at low concentrations.

CONCLUSION

Despite the large differences in the genetic background of S. aureus 10379 and 121940, some sub-inhibitory concentrations of beta-lactam antibiotics are able to promote biomass and biofilm viability of both two isolates.

Prevalence and molecular characteristics of Staphylococcus aureus in raw milk and milk products in Ethiopia: a systematic review and meta-analysis

Background

Staphylococcus aureus is an important opportunistic pathogen of raw milk and milk products, and the enterotoxins cause food poisoning. Milk and milk products are important reservoirs of enterotoxin-producing S. aureus. The aims of this systematic review were to estimate the pooled prevalence of S. aureus, including methicillin-resistant Staphylococcus aureus (MRSA), and to summarize their molecular characteristics, assess the potential sources of S. aureus contamination in bulk milk and analyse the antimicrobial resistance patterns of the isolates.

Methods

Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we searched publicly available scientific online databases and search engines: PubMed, Research for Life, African Journal Online (AJOL), and Google Scholar. In addition, the reference lists of the identified studies were manually checked for relevant literature. A random effects model using the DerSimonian method was used to compute pooled prevalence estimates, and the data were transformed using variance stabilizing Freeman-Tukey double arcsine transformation.

Results

A total of 38 studies were included in this systematic review. The pooled prevalence of S. aureus was highest in raw cow milk (30.7%), followed by camel milk (19.3%), goat milk (13.6%) and pasteurized milk (3.8%). The pooled prevalence of S. aureus in locally produced soft cheese (ayib) and traditional fermented milk (ergo) was 18.6% and 14.9%, respectively. The pooled prevalence of MRSA in milk and milk products was 0.73%. In this study, 58.9% of S. aureus isolates recovered from milk and milk products harbored at least one type of enterotoxin gene. Raw milk of the three species (cow, goat and camel) showed the highest S. aureus pooled prevalence rate at processing plants (50.3%), followed by milk collection centers (MCCs) (47.1%), selling points (34.5%), farm bulk milk (25.8%), milking buckets (24.8%) and udder milk (20.3%). Water for washing milking utensils (39.3%) was more contaminated than swab samples from farm workers’ nares (31.5%), milkers’ hands (25.9%), MCCs containers (23.8%), bulk tanks (20.4%), udders (15.6%), milking buckets (14.2%) and towels (10%). S. aureus isolates were highly resistant to penicillin G (92%), followed by ampicillin (82%) and amoxicillin (62.6%). The pooled multidrug resistance (MDR) was high (62.1%).

Conclusion

This systematic review revealed a high and increasing level of S. aureus contamination of raw milk from udder to MCCs or processing plants. Enterotoxin genes and MRSA were reported in milk, milk products and samples from farm workers. S. aureus showed resistance to different antimicrobial agents, with β-lactams showing the highest pooled antimicrobial resistance and the level of MDR was high. The results of this study indicated that the consumption of raw milk and milk products may predispose consumers to staphylococcal food poisoning. Application of good hygiene and handling practices across the dairy value chain starting from farm, udder health, milk cooling, heat treatment of milk before drinking and rational use of antibiotics in veterinary medicine can reduce the potential health risks from S. aureus and MRSA contamination of milk and milk products.

Anthroponotic-Based Transfer of Staphylococcus to Dog: A Case Study

Although usually harmless, Staphylococcus spp. can cause nosocomial and community-onset skin and soft tissue infections in both humans and animals; thus, it is considered a significant burden for healthcare systems worldwide. Companion animals have been identified as potential reservoirs of pathogenic Staphylococcus with specific reference to Methicillin Resistant Staphylococcus aureus (MRSA). In this study, we investigated the circulation and the genetic relationships of a collection of Staphylococcus spp. isolates in a family composed of four adults (a mother, father, grandmother, and grandfather), one child, and a dog, which were sampled over three years. The routes of transmission among humans and between humans and the dog werelyzed. The results displayed the circulation of many Staphylococcus lineages, belonging to different species and sequence types (ST) and being related to both human and pet origins. However, among the observed host-switch events, one of them clearly underpinnthroponotic route from a human to a dog. This suggests that companion animals can potentially have a role as a carrier of Staphylococcus, thus posing a serious concern about MRSA spreading within human and animal microbial communities.