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This thesis is about the abilities of two plant extracts to cause aggregation or “clumping” of Staphylococcus aureus. This project is in response to rising levels of antibiotic-resistant bacteria, and a lack of methods to control the dispersal of bacteria of agricultural origin. As the implementation of antibiotics in the agricultural sector has increased since the discovery of antibiotics, concerns regarding human health have arisen. The use of antibiotics acts as a selection pressure against bacteria that are susceptible to the antibiotic’s effects. This allows for those bacteria that possess antibiotic resistance to reproduce, creating strains of mainly antibiotic-resistant bacteria. The purpose of this thesis is to investigate two clump-inducing plant extracts that are a potential tool to limit the dispersal of bacteria in solution (ex. Bacteria in agricultural wastewater). By promoting clumping in the bacteria, it is thought that the bacteria’s dispersal will be limited, decreasing instances of infection, thereby indirectly reducing the need for antibiotic use. The two plant extracts studied here were selected from a library of bacterial clump-inducing plant extracts. They come from different botanical families and induce clump formation in S. aureus resulting in differing clump phenotypes. In addition to clump formation, both plant extracts cause a significant reduction in the growth of S. aureus (F (3, 72) = 4.022E+17, p < 0.001), (F (3, 58) = 185, p < 0.001). It is found that clumping molecules act in an adhesive manner and that the bacteria do not play an active role in clump formation. With this finding the first steps of affinity purification of clumping molecules were carried out for further identification of their chemical identities. This thesis outlines a procedure to study, compare and purify other clump-inducing plant extracts, many of which have not been investigated.

This thesis is about the abilities of two plant extracts to cause aggregation or “clumping” of Staphylococcus aureus. This project is in response to rising levels of antibiotic-resistant bacteria, and a lack of methods to control the dispersal of bacteria of agricultural origin. As the implementation of antibiotics in the agricultural sector has increased since the discovery of antibiotics, concerns regarding human health have arisen. The use of antibiotics acts as a selection pressure against bacteria that are susceptible to the antibiotic’s effects. This allows for those bacteria that possess antibiotic resistance to reproduce, creating strains of mainly antibiotic-resistant bacteria. The purpose of this thesis is to investigate two clump-inducing plant extracts that are a potential tool to limit the dispersal of bacteria in solution (ex. Bacteria in agricultural wastewater). By promoting clumping in the bacteria, it is thought that the bacteria’s dispersal will be limited, decreasing instances of infection, thereby indirectly reducing the need for antibiotic use. The two plant extracts studied here were selected from a library of bacterial clump-inducing plant extracts. They come from different botanical families and induce clump formation in S. aureus resulting in differing clump phenotypes. In addition to clump formation, both plant extracts cause a significant reduction in the growth of S. aureus (F (3, 72) = 4.022E+17, p < 0.001), (F (3, 58) = 185, p < 0.001). It is found that clumping molecules act in an adhesive manner and that the bacteria do not play an active role in clump formation. With this finding the first steps of affinity purification of clumping molecules were carried out for further identification of their chemical identities. This thesis outlines a procedure to study, compare and purify other clump-inducing plant extracts, many of which have not been investigated.

This thesis is about the abilities of two plant extracts to cause aggregation or “clumping” of Staphylococcus aureus. This project is in response to rising levels of antibiotic-resistant bacteria, and a lack of methods to control the dispersal of bacteria of agricultural origin. As the implementation of antibiotics in the agricultural sector has increased since the discovery of antibiotics, concerns regarding human health have arisen. The use of antibiotics acts as a selection pressure against bacteria that are susceptible to the antibiotic’s effects. This allows for those bacteria that possess antibiotic resistance to reproduce, creating strains of mainly antibiotic-resistant bacteria. The purpose of this thesis is to investigate two clump-inducing plant extracts that are a potential tool to limit the dispersal of bacteria in solution (ex. Bacteria in agricultural wastewater). By promoting clumping in the bacteria, it is thought that the bacteria’s dispersal will be limited, decreasing instances of infection, thereby indirectly reducing the need for antibiotic use. The two plant extracts studied here were selected from a library of bacterial clump-inducing plant extracts. They come from different botanical families and induce clump formation in S. aureus resulting in differing clump phenotypes. In addition to clump formation, both plant extracts cause a significant reduction in the growth of S. aureus (F (3, 72) = 4.022E+17, p < 0.001), (F (3, 58) = 185, p < 0.001). It is found that clumping molecules act in an adhesive manner and that the bacteria do not play an active role in clump formation. With this finding the first steps of affinity purification of clumping molecules were carried out for further identification of their chemical identities. This thesis outlines a procedure to study, compare and purify other clump-inducing plant extracts, many of which have not been investigated.

Even with the best infection control protocols in place, the risk of a hospital-acquired infection of the surface of an implanted device remains significant. A bacterial biofilm can form and has the potential to escape the host immune system and develop resistance to conventional antibiotics, ultimately causing the implant to fail, seriously impacting patient well-being. Here, we demonstrate a 4 log reduction in the infection rate by the common pathogen S. aureus of 3D-printed polyaryl ether ketone (PAEK) polymeric surfaces by covalently binding the antimicrobial peptide Mel4 to the surface using plasma immersion ion implantation (PIII) treatment. The surfaces with added texture created by 3D-printed processes such as fused deposition-modelled polyether ether ketone (PEEK) and selective laser-sintered polyether ketone (PEK) can be equally well protected as conventionally manufactured materials. Unbound Mel4 in solution at relevant concentrations is non-cytotoxic to osteoblastic cell line Saos-2. Mel4 in combination with PIII aids Saos-2 cells to attach to the surface, increasing the adhesion by 88% compared to untreated materials without Mel4. A reduction in mineralisation on the Mel4-containing surfaces relative to surfaces without peptide was found, attributed to the acellular portion of mineral deposition.

Existing recommended first-line antibiotic agents for MRSA pneumonia have several shortcomings. We reviewed 29 cases of community- and hospital-acquired MRSA pneumonia managed at our hospital. Lincosamide monotherapy was administered to 21/29 (72%) and was the predominant antibiotic regimen (> 50% course duration) in 19/29 (66%). Patients receiving lincosamide-predominant monotherapy were no more likely to die or require intensive care unit admission than patients receiving vancomycin-predominant monotherapy (5/19 (26%) versus 4/7 (57%), p = 0.19); 5/7 (71%) patients admitted to ICU and 4/5 (80%) bacteraemic patients received lincosamide-predominant monotherapy. MRSA pneumonia can be safely treated with lincosamide monotherapy if the isolate is susceptible.

This work was financially supported by the Spanish Ministry of Science, Innovation and Universities grant PID2020-113494RB-I00/AEI/10.13039/501100011033. (Agencia Española de Investigación/Fondo Europeo de Desarrollo Regional, European Union) to I.L., and JSPS KAKENHI grant number JP23H02719 and the Institute for Fermentation, Osaka to H.H, respectively. P. I-S. was supported by a F.P.I. (PRE2021-097385) contract from the Spanish Ministry of Science, Innovation and Universities. A.S.M. was supported by a contract from the University Department of Navarra government (Res. 229E/2020 Microbiomics grant). The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication. Open access funding provided by Universidad Publica de Navarra., Peer Reviewed, Postprint (published version)

Background: With the rising risk of antibiotic resistance, our ability to combat Staphylococcus aureus (S. aureus) in skin and soft tissue infections (SSTIs) is being compromised. Purpose: This study aimed to determine the activity of several aqueous extracts of black mahlab seeds (maceration, infusion, and decoction) against S. aureus-associated SSTIs. Methods: We employed the disc diffusion Kirby-Bauer method to evaluate the anti-staphylococcal activity of the extracts. Furthermore, we used various extract concentrations to calculate each extract's minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against S. aureus. Result: The results revealed enhanced anti-staphylococcal activity, with inhibition zones measuring 11.5, 22.5, and 26.5 mm at concentrations of 25, 50, and 100 mg/ml, respectively. These effects were similar to ampicillin against S. aureus and significantly higher (p 0.05) than gentamicin. The extracts showed antibacterial activity with MICs and MBCs ranging from 12.5 to 25 mg/ml. Conclusion: Overall, compared to the clinically prescribed antibiotics, ampicillin, and gentamicin, black mahlab seed extract obtained by water maceration exhibits increased anti-staphylococcal activity associated with SSTIs.

The presence of pathogens in food has increased awareness of food safety, but it also causes large economic losses. Fresh meat and meat products contain a sufficient quantity of proteins, lipids, water, and a favorable pH that stimulates the growth of various microorganisms, including pathogens.The aim of this study was to investigate the efficacy of Brevibacillus laterosporus BGSP7 (CFS-BGSP7) and BGSP9 (CFS-BGSP9) cell-free supernatants in the control of Listeria monocytogenes and Staphylococcus aureus in raw meat and meat products.Raw meat and meat products were sliced and then aseptically treated by immersion for 2 minutes into solutions containing: i) CFS-BGSP7; ii) CFS-BGSP9; iii) no treatment. The samples were then artificially contaminated with: Group I – L. monocytogenes (~4 log cfu g-1); Group II – S. aureus LMM322 (~4 log cfu g-1). Each sample was individually aseptically vacuum-packed and stored at 4°C for 8 weeks. The number of surviving bacteria in the samples were analyzed immediately after contamination with L. monocytogenes and S. aureus and at regular time-intervals: after 1, 3, 5 and 8 weeks of storage at 4°C.Meat samples treated with CFS-BGSP7 and CFS-SP9 showed a significant decrease in the cell counts of L. monocytogenes and S. aureus. When meat samples treated with CFS-BGSP7 and CFS-BGSP9 are compared, the results show a more intense reduction rate of both L. monocytogenes and S. aureus in all samples treated with CFS-BGSP7.

Ischemic teat necrosis (ITN) is a growing problem in the dairy industry characterized by teat lesions, necrosis, pruritus and automutilation. Despite the economic and welfare consequences, there is no treatment, and the etiology of the disease remains poorly understood. The aim of this study was to investigate ITN by analyzing its clinical presentation, potential risk factors and microbial involvement. Methods included collection of milk and swab samples from affected cows over a period of one-and-a-half years and completion of questionnaires by veterinarians and farmers. Microbial testing included PCR testing for Treponema spp. and cultural testing by anaerobic and aerobic incubation on blood agar. The results showed a high and significant prevalence of Treponema spp. and Staphylococcus aureus in affected teats compared to non-ITN-affected control teats, indicating their potential role in the development of ITN. Other factors such as edema and milking practices also appear to contribute to the tissue damage. First-lactation and early-lactation heifers are particularly at risk. In conclusion, ITN appears to have a multifactorial etiology with both infectious and non-infectious factors playing a role. Further research is needed to better understand the complex interplay of these factors and to develop effective prevention and management strategies.

Background The cell envelope of Staphylococcus aureus contains 2 major secondary cell wall glycopolymers: capsular polysaccharide (CP) and wall teichoic acid (WTA). Both CP and WTA are attached to the cell wall and play distinct roles in S. aureus colonization, pathogenesis, and bacterial evasion of host immune defenses. We aimed to investigate whether CP interferes with WTA-mediated properties. Methods Strains with natural heterogeneous expression of CP, strains with homogeneous high CP expression, and CP-deficient strains were compared regarding WTA-dependent phage binding, cell adhesion, IgG deposition, and virulence in vivo. Results WTA-mediated phage adsorption, specific antibody deposition, and cell adhesion were negatively correlated with CP expression. WTA, but not CP, enhanced the bacterial burden in a mouse abscess model, while CP overexpression resulted in intermediate virulence in vivo. Conclusions CP protects the bacteria from WTA-dependent opsonization and phage binding. This protection comes at the cost of diminished adhesion to host cells. The highly complex regulation and mostly heterogeneous expression of CP has probably evolved to ensure the survival and optimal physiological adaptation of the bacterial population as a whole., BACKGROUND: The cell envelope of Staphylococcus aureus contains 2 major secondary cell wall glycopolymers: capsular polysaccharide (CP) and wall teichoic acid (WTA). Both CP and WTA are attached to the cell wall and play distinct roles in S. aureus colonization, pathogenesis, and bacterial evasion of host immune defenses. We aimed to investigate whether CP interferes with WTA-mediated properties.METHODS: Strains with natural heterogeneous expression of CP, strains with homogeneous high CP expression, and CP-deficient strains were compared regarding WTA-dependent phage binding, cell adhesion, IgG deposition, and virulence in vivo.RESULTS: WTA-mediated phage adsorption, specific antibody deposition, and cell adhesion were negatively correlated with CP expression. WTA, but not CP, enhanced the bacterial burden in a mouse abscess model, while CP overexpression resulted in intermediate virulence in vivo.CONCLUSIONS: CP protects the bacteria from WTA-dependent opsonization and phage binding. This protection comes at the cost of diminished adhesion to host cells. The highly complex regulation and mostly heterogeneous expression of CP has probably evolved to ensure the survival and optimal physiological adaptation of the bacterial population as a whole.

Ischemic teat necrosis (ITN) is a growing problem in the dairy industry characterized by teat lesions, necrosis, pruritus and automutilation. Despite the economic and welfare consequences, there is no treatment, and the etiology of the disease remains poorly understood. The aim of this study was to investigate ITN by analyzing its clinical presentation, potential risk factors and microbial involvement. Methods included collection of milk and swab samples from affected cows over a period of one-and-a-half years and completion of questionnaires by veterinarians and farmers. Microbial testing included PCR testing for Treponema spp. and cultural testing by anaerobic and aerobic incubation on blood agar. The results showed a high and significant prevalence of Treponema spp. and Staphylococcus aureus in affected teats compared to non-ITN-affected control teats, indicating their potential role in the development of ITN. Other factors such as edema and milking practices also appear to contribute to the tissue damage. First-lactation and early-lactation heifers are particularly at risk. In conclusion, ITN appears to have a multifactorial etiology with both infectious and non-infectious factors playing a role. Further research is needed to better understand the complex interplay of these factors and to develop effective prevention and management strategies.

Background Bone infections with Staphylococcus aureus are notoriously difficult to treat and have high recurrence rates. Local antibiotic delivery systems hold the potential to achieve high in situ antibiotic concentrations, which are otherwise challenging to achieve via systemic administration. Existing solutions have been shown to confer suboptimal drug release and distribution. Here we present and evaluate an injectable in situ-forming depot system termed CarboCell. The CarboCell technology provides sustained and tuneable release of local high-dose antibiotics. Methods CarboCell formulations of levofloxacin or clindamycin with or without antimicrobial adjuvants cis-2-decenoic acid or cis-11-methyl-2-dodecenoic acid were tested in experimental rodent and porcine implant-associated osteomyelitis models. In the porcine models, debridement and treatment with CarboCell-formulated antibiotics was carried out without systemic antibiotic administration. The bacterial burden was determined by quantitative bacteriology. Results CarboCell formulations eliminated S. aureus in infected implant rat models. In the translational implant-associated pig model, surgical debridement and injection of clindamycin-releasing CarboCell formulations resulted in pathogen-free bone tissues and implants in 9 of 12 and full eradication in 5 of 12 pigs. Conclusions Sustained release of antimicrobial agents mediated by the CarboCell technology demonstrated promising therapeutic efficacy in challenging translational models and may be beneficial in combination with the current standard of care.

La résistance aux agents antimicrobiens (RAM) est un phénomène naturel répandu chez de nombreuses bactéries mais ayant pris une ampleur alarmante depuis l’introduction massive de molécules antibactériennes au sein des populations humaines et animales au cours des dernières décennies. L’émergence et la propagation de bactéries résistantes aux antimicrobiens est un problème contemporain majeur qui nécessite, entre autres, le développement de nouveaux composés antibactériens n’étant pas susceptible à la RAM. Dans cette optique et en lien avec l’utilisation traditionnelle des bourgeons de peuplier baumier (Populus balsamifera), l’équipe du Laboratoire d’analyse et de séparation des essences végétales (LASEVE) a identifié une nouvelle famille de composés naturels antibactériens : les balsacones. Celles-ci ont une activité antibactérienne intéressante contre le staphylocoque doré (Staphylococcus aureus) et le staphylocoque doré résistant à la méticilline (SARM), une souche multirésistante particulièrement problématique dans le milieu hospitalier. Cependant, malgré cette activité antibactérienne intéressante, l’isolation des balsacones dans les bourgeons de peuplier baumier est fastidieuse et onéreuse, ce qui représente un défi de production. Quant à elle, la synthèse totale des balsacones nécessite de nombreuses étapes et repose sur l’utilisation de précurseurs non renouvelables issus de la pétrochimie. Une alternative attrayante est l’hémisynthèse des balsacones à partir des dihydrochalcones (DHC) précurseurs présentes dans les bourgeons de P. balsamifera. Cependant, cette méthode requiert aussi des étapes d’isolation pour obtenir ces DHC. Ces différents enjeux encouragent donc la recherche de voies innovantes de production des balsacones. Ce projet de maîtrise consistait à mettre au point et à optimiser une nouvelle méthode de production de balsacones. Cette approche alternative consiste à convertir les DHC en balsacones directement dans un extrait de bourgeons de P. ba

Background: With the rising risk of antibiotic resistance, our ability to combat Staphylococcus aureus (S. aureus) in skin and soft tissue infections (SSTIs) is being compromised. Purpose: This study aimed to determine the activity of several aqueous extracts of black mahlab seeds (maceration, infusion, and decoction) against S. aureus-associated SSTIs. Methods: We employed the disc diffusion Kirby-Bauer method to evaluate the anti-staphylococcal activity of the extracts. Furthermore, we used various extract concentrations to calculate each extract's minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) against S. aureus. Result: The results revealed enhanced anti-staphylococcal activity, with inhibition zones measuring 11.5, 22.5, and 26.5 mm at concentrations of 25, 50, and 100 mg/ml, respectively. These effects were similar to ampicillin against S. aureus and significantly higher (p 0.05) than gentamicin. The extracts showed antibacterial activity with MICs and MBCs ranging from 12.5 to 25 mg/ml. Conclusion: Overall, compared to the clinically prescribed antibiotics, ampicillin, and gentamicin, black mahlab seed extract obtained by water maceration exhibits increased anti-staphylococcal activity associated with SSTIs.

Staphylococcus aureus es un patógeno alimentario que representa un grave riesgo para los consumidores, ya que puede inducir infecciones gastrointestinales. En consecuencia, es crucial desarrollar protocolos destinados a reducir y, en última instancia, eliminar este microorganismo en los productos alimenticios. Los subproductos vegetales, como los aceites esenciales, pueden representar una buena alternativa alternativa para el control microbiológico en alimentos. En este estudio, desarrollamos nanoemulsiones a diferentes concentraciones utilizando aceites esenciales de dos subproductos vegetales para investigar su efecto potencial sobre S. aureus. Las curvas de crecimiento se generaron utilizando un Bioscreen C y los datos se analizaron posteriormente utilizando paquetes de R. Nuestros resultados muestran que diferentes concentraciones de ambos aceites esenciales indujeron comportamientos diferentes en el crecimiento de S. aureus durante periodos de 48 horas, lo que sugiere efectos tanto bactericidas como bacteriostáticos y, por lo tanto, diferentes aplicaciones para el control de patógenos en la industria alimentaria.

While several environmental factors contribute to the evolutionary diversification of the pathogenic bacterium Pseudomonas aeruginosa during cystic fibrosis lung infections, relatively little is known about the impact of the surrounding microbiota. By using in vitro experimental evolution, we show that the presence of Stenotrophomonas maltophilia, Staphylococcus aureus, or them both, prevent the evolution of loss of virulence, which repeatedly occurs in the absence of these species due to mutations in regulators of the Pseudomonas Quinolone Signal quorum sensing system, vqsM and pqsR. Moreover, the strength of the effect of co-occurring species is attenuated through changes in the physical environment by the addition of mucin, resulting in selection for phenotypes resembling those evolved in the absence of the co-occurring species. Together, our findings show that variation in mucosal environment and the surrounding polymicrobial environment can determine the evolutionary trajectory of P. aeruginosa, partly explaining its diversification and pathoadaptation from acute to chronic phenotype during cystic fibrosis lung infections.

Staphylococcus aureus, a frequent commensal of the human microbiota, also frequently associated with various infections. This study aimed to genetically characterize foodborne methicillin resistant S. aureus (MRSA) in Oran, Algeria. From a total of 474 food matrices, 30 MRSA strains were isolated and characterized using whole genome sequencing (WGS) and bioinformatics. The genomes were assessed for antimicrobial resistance and virulence genes, sequence and spa types and single nucleotide polymorphism (SNP) to establish their relationship. The prevalence of S. aureus was 34.38% with MRSA accounting for 18.40%. MRSA strains showed high resistance to penicillinG, ampicillin and tetracycline. However, inconsistencies were noted between phenotypic and genotypic resistance for methicillin, aminoglycosides, and phenicolates, with mecA gene identified in three isolates. The isolates revealed eight different sequence types (predominantly ST97 and ST45) and eleven spa types (mainly t230 and t8503), correlating with SNP clusters except for isolates belonging to ST7200.86.66% of isolates harboured at least one enterotoxin gene underscores their potential public health threat. This investigation highlights the genetic heterogeneity among S. aureus regarding virulence and antimicrobial resistance, shedding light into food safety in Algeria and the ease of using WGS approach to rapidly characterize bacterial pathogens in community environments.

Background/Aim.Available face masks, used to protect the respiratory system from various types of pathogens, show unsatisfactory efficiency because the size of viruses like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is much smaller than the void spaces in these masks. Difficult breathing through some masks quickly tires out, which makes ordinary people avoid wearing them. These facts suggest that a new strategy is desirable for designing protective face masks. The aim of the study was to present new filters for face masks to protectpeople exposed to high concentrations of bacteria and viruses, particularly SARS-CoV-2. Methods.Filters for these masks were manufactured of dense cotton fabric impregnated with silver quantum dots. The filters were characterized by scanning electron microscopy and ion-coupledplasma mass spectrometry. Wettability properties were determined by measuring contact angles with water, and a color fastness test was performed. Antibacterial assay was performed using Staphylococcus (S.) aureus. Viability quantitative polymerase chain reaction (qPCR) for virus integrity assay and reverse transcription qPCR (RT-qPCR) assay were used for antiviral activity assessment. Results.In vitroassays showed extremely high efficiency of these filters in destroying S. aureus and SARS-CoV-2 virus. The filters also showed high safety and easy breathing possibilities. Conclusion.The high efficiency of these masks against SARS-CoV-2 has been demonstrated through numerous tests, and they have been approved as anti-SARS-CoV-2 masks for the first time in the world. In the meantime, this solution has been applied in practice, and the data obtained about that are very encouraging., Uvod/Cilj. Dostupne maske za lice, koje se koriste za zaštitu respiratornog sistema od različitih vrsta patogena, ne pokazuju zadovoljavajucu efikasnost, jer je virus poput korona virusa izazivača teškog akutnog respiratornog sindroma, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mnogo manji od pora u ovim maskama. Teško disanje kroz neke maske brzo dovodi do zamora, zbog čega ljudi izbegavaju da ih nose. Te činjenice sugerišu da je poželjna nova strategija u dizajniranju zaštitnih maski za lice. Cilj rada bio je da se predstave novi filteri za maske za zaštitu osoba izloženih visokoj koncentraciji bakterija i virusa, posebno SARS-CoV-2. Metode. Filteri za te maske izrađeni su od guste pamučne tkanine impregnirane srebrnim kvantnim tačkama. Filteri su okarakterisani skenirajucom elektronskom mikroskopijom i jonsko-spregnutom plazma masenom spektrometrijom. Svojstva vlaženja određivana su merenjem kontaktnih uglova sa vodom, a ispitana je i postojanost boje tih filtera. Antibakterijski test izveden je korišcenjem Staphylococcus (S.) aureus. Za procenu antivirusne aktivnosti korišceni su test viabilnosti quantitative polymerase chain reaction (qPCR) – test integriteta virusa i test reverzne transkriptaze qPCR (RT-qPCR). Rezultati. In vitro testovi pokazali su izuzetno visoku efikasnost ispitanih filtera u uništavanju bakterije S. aureus i virusa SARS-CoV-2. Filteri su, takođe, pokazali visoku sigurnost i mogućnost za lako disanje. Zaključak. Visoka efikasnost ispitivanih maski protiv SARS-CoV-2 dokazana je mnogobrojnim testovima i one su, po prvi put u svetu, odobrene kao anti-SARS-CoV-2 maske. U međuvremenu, ovo rešenje primenjeno je u praksi, a podaci o tome su veoma ohrabrujuci.

Cilj ovog rada je ispitivanje antimikrobnog potencijala metanolnih ekstrakata smole Boswellia serrata protiv tri soja bakterijskih patogena kože: Staphylococcus aureus, Pseudomonas aeruginosa i Listeria monocytogenes. Smola B. serrata, prepoznatljiva po upotrebi u tradicionalnoj medicini, analizirana je primenom visoko-efikasne tankoslojne hromatografije (High-Performance Thin-Layer Chromatography, HPTLC) u kombinaciji sa antimikrobnom detekcijom kako bi se identifikovali biološki aktivna jedinjenja. Ekstrakti tamjana prikupljeni iz različitih geografskih područja pokazali su značajan antibakterijski potencijal, posebno prema patogenima otpornim na konvencionalne antibiotike. Bioautografski testovi ukazali su na prisustvo aktivnih zona koje inhibiraju rast bakterija. Citotoksičnost najaktivnijih ekstrakata ispitana je na imortalizovanom humanom ćelijskom linijom - keratinocitima (HaCaT), pri čemu su utvrđene koncentracije koje ne izazivaju štetne efekte. Rezultati ukazuju na potencijalnu primjenu B. serrata u razvoju novih antibakterijskih agenasa.

The aim of the present study was to identify the phytochemical constituents Azadirachta indica (Neem) leaves and evaluate their antibacterial and anti-inflammatory activities. The antibacterial properties of Azadirachta indica leaf extract were assessed using solvents such as ethanol, ethyl acetate, methanol and distilled water. These extracts were tested against two bacterial strains: Staphylococcus aureus and Streptococcus mutans. The results indicated that the ethyl acetate extract exhibited the highest zone of inhibition against both bacterial strains. Specifically, the zone for S. aureus ranged from 15.66-20.30 mm, while for S. mutans, it ranged from 21.50-27.56 mm. These finding demonstrate that A. indica possesses significant antimicrobial activity against both bacterial strains, with the ethyl acetate extract showing the most Pronounced inhibitory effect. Given its superior antibacterial activity, the ethyl acetate extract was further selected for the evaluation of its anti-inflammatory properties. Additionally, the chemical constituents responsible for these bioactivities were found out by using Gas Chromatography-Mass Spectrometry (GC-MS).

Objective: Antibiotic resistance is an important epidemiological problem that is on the global agenda and solutions are sought. As the morbidity and mortality rates caused by this problem increase every year, studies on developing new alternative active molecules are gaining momentum. Theoretical Framework: Determining the antibacterial activity of the fig (Ficus carica), which has bioactive content and is the first in production in the world, against methicillin-resistant Staphylococcus aureus bacterial strain, which is the leading antibiotic resistance, by computer-based molecular docking studies. Method: The binding energies of the interaction of the protein that causes antibiotic resistance in MRSA strains with the molecules of the fig plant were detected. Among the molecules with high binding energy in the protein-ligand structure, those are suitable for the drug likeness parameters were evaluated. Results and Discussion: Molecules with high affinity and sufficient bioavailability of bioactive molecules found in fig can be developed and used in alternative antibiotic studies. The findings obtained will support in vivo and in vitro studies on the antibacterial activity of figs and bring different perspective to new studies. Research Implications: Molecular docking study with 177 active molecules of the Ficus carica plant, 4 candidate active molecules that passed the druglikeness parameters and showed high binding energy were determined as quercetin, kaempherol, coumarins and riboflavin. Originality/Value: It is envisaged that the studies of these candidate molecules, which have been identified, will contribute greatly to experimental studies in terms of both time and cost.

Background: Allergic rhinitis (AR) subjects might have their microenvironment changed due to pathogenesis and living environment. Whether the nasal microbe in AR children differs from healthy subjects and how it interplays with dermal, oral and indoor dust microbe needs to be elucidated. Methods: In this case-control study, we analyzed and compared the bacterial characterization and associations in nasal, dermal, oral swab samples and dust samples in 62 children with physician-diagnosed AR(cases) and 51 age- and gender-matched healthy ones with no history of allergic diseases(controls). Full-length 16S rRNA sequencing(swabs) and shotgun metagenomics(dust) were applied. Bacterial diversity, composition, abundance difference characteristics and fast expectation-maximization for microbial source tracking(FEAST) analysis were performed and compared between cases and controls. Results: The alpha-diversity of dust microorganisms in AR was lower than that in control group (P = 0.034), and the beta-diversity indices of microorganisms in nasal cavity (P = 0.020), skin (P = 0.001) and dust (P = 0.004) were significantly different from those in control group. At species levels, a total of 10, 15, 12, and 15 bacterial species were differentially enriched in either cases or controls in nasal, dermal, oral, and dust samples, respectively(Linear Discriminant Analysis(LDA) score > 2, P < 0.05). Staphylococcus epidermidis was the single species simultaneously more abundant in nasal, dermal and dust samples in AR children. By FEAST analysis, 8.85% and 10.11% of S. epidermidis in AR dermal and dust samples came from nasal cavity. These proportions were significantly higher than those in controls (2.70% and 3.86%) (P < 0.05). The same significantly higher transfer proportions(P < 0.05) were observed for Staphylococcus aureus enriched in the nasal cavity in AR children. Classification models by random forest regression at species levels showed, bacterial species enriched in

I denna studie undersöktes om inkubationstiden innan påbörjad diskdiffusion påverkar resistensbestämningen för Staphylococcus aureus, Streptococcus pneumoniae samt Escherichia coli. Antibiotikaresistens hos bakterier är ett växande problem som orsakar svårigheter vid behandling av bakteriella infektioner. Resistensbestämning utförs för att minska problemet och för att undvika felanvändning av antibiotika. Diskdiffusionsmetoden är en av de mest använda metoderna för att utföra resistensbestämning och är standardiserad av European Committee on Antimicrobial Susceptibility Testing (EUCAST). 10 S. aureus-, 10 S. pneumoniae- och 12 E. coli-stammar inklusive en kontrollstam för varje art, odlades fram på blodagar och inkuberades i 6h, 24h, 48h och 72h innan resistensbestämning påbörjades. Resistensbestämning utfördes sedan i triplikat och lästes av efter 16-20h enligt metod. En signifikant skillnad i resistenszoner kunde påvisas för samtliga stammar och antibiotika förutom för E. coli med Cefotaxim vid 6h, 48, och 72h jämfört mot 24h. Förutom dessa resultat, fick sju av 32 stammar en annan SIR-klassificering jämfört mot standardtid (24h). Slutsatsen är att främst längre, men även kortare inkubationstider, kan leda till felaktiga resistenszoner och även SIR-klassificering, vilket skulle kunna resultera i felaktiga behandlingsval., This study aimed to investigate if the incubation time before performed disk diffusion affects susceptibility testing for Staphylococcus aureus, Streptococcus pneumoniae and Escherichia coli. Antibiotic resistance is a growing problem making infectious diseases harder to treat. Antibiotic susceptibility testing is performed to reduce this problem. The disk diffusion method is one of the most common used methods for susceptibility testing and is standardized by European Committee on Antimicrobial Susceptibility Testing (EUCAST). 10 strains of S. aureus, 10 of S. pneumoniae and 12 of E. coli and corresponding control strain for each species were inoculated on blood-agar and incubated 6h, 24h, 48h and 72h prior to susceptibility testing. After each incubation-time, disk diffusion test was performed three times for each strain and inhibition zones were measures after 16-20h. Results shows a significant difference in all strains and antibiotics except for E. coli with Cefotaxim at 6h, 48h and 72h compared to 24h. Besides these findings, seven out of 32 strains were categorized with another SIR-classification compared to standard (24h). In conclusion, most of all longer, but also shorter incubation-time can result in incorrect inhibition zones and SIR classification, which could affect treatment choice.

Staphylococcus aureus (S. aureus) is a gram-positive bacterium that can cause severe infections such as pneumonia, osteomyelitis, and endocarditis when it breaches the skin. This study aimed to enhance the chemoenzymatic radiosynthesis of 2-deoxy-2-[18F]-fluoro-sakebiose ([18F]FSK), a radiotracer potentially useful for imaging S. aureus infections. By optimizing the synthesis of 2-deoxy-2-[19F]-fluoro-sakebiose ([19F]FSK), we identified key factors—such as increased enzyme concentration and decreased precursor levels—that significantly improved the yield. Applying these optimized conditions to the synthesis of [18F]FSK resulted in a 30% increase in the radiochemical yield (RCY%) from the control experiment. In vitro evaluation showed that [18F]FSK was successfully incorporated into two strains of S. aureus, suggesting its potential utility for imaging bacterial infections in vivo. This work lays the groundwork for using [18F]FSK in PET/CT imaging to diagnose and monitor S. aureus infections.

Background: Infectious diseases that women often experience in obstetric cases are usually problems in the vaginal area, puerperal infections and some cases of infections of the reproductive organs. Efforts to reduce the negative impact of infection can be done by looking for compounds that have antimicrobial activity, one of which is Telang Leaf (Clitoria ternatea). Telang leaves contain flavonoids, flavanols, kaempferol, quercetin and mirisetin. From the results of various studies Telang Leaves have a pharmacological influence as an antimicrobial. Objectives: The purpose of this study was to determine the activity of telang leaf extract against the growth of Staphylococcus aureus bacteria and Candida albicans fungi based on the diameter of the inhibitory zone. Design: This research used experimental design. Methods: The research method used is experimental laboratories. The test was carried out by extracting Telang leaves by the maceration method, then evaporated with a rotary evaporator so that a concentrated extract was obtained. Extracts Made concentrations of 10%, 20%, 30%, 40% and 50%. The antimicrobial activity test of the extract against Staphylococcus aureus bacteria and candida albicans fungus was carried out by disc diffusion method. Results: The results showed that negative controls did not have an inhibitory zone diameter. The average diameter of the inhibition zone of telang leaf extract in Staphylococcus aureus is the highest with a concentration of 50%, which is 17.8 mm and a positive control of 42.6 mm. while in candida albicans fungus with a concentration of 50% with an inhibitory diameter of 16.5 mm and a positive control of 26.2 mm. Conclusion: The conclusion is that telang leaves have antimicrobial activity at a concentration of 50% against Staphylococcus aureus and candida albicans. So that, telang leaf extract can be developed as a treatment in infectious diseases in case of obstetrics.

This article presents analyzed data on the antimicrobial, barrier, and mechanical properties inherent to films created by blending carrot pomace with wheat gluten and polyglycerol-3 plasticizer and combined with varying contents (0 wt.%, 3 wt.%, and 5 wt.%) of eugenol, a natural antimicrobial compound derived from essential oils. The integration of carrot pomace, wheat gluten, plasticizer, and eugenol involved meticulous mortar and pestle processing, ensuring a homogenous blend. Subsequently, the mixture was compression-molded in a hydraulic press to fabricate the films. Standard bacteria strains-Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538-are used in the antimicrobial evaluation, and antimicrobial efficacy is measured using OD600 measurements. Water vapor permeability (WVP) measurement effectively defines the films' potential to prevent water vapor infiltration. Mechanical properties are assessed by determining elastic modulus, tensile strength, and elongation at break, which together reveal the films' adaptive flexibility and durability. The dataset presented herein holds substantial promise for food packaging applications. Researchers in the food packaging industry can leverage the antimicrobial and barrier property data to design novel packaging materials, potentially enhancing shelf-life and food safety. Engineers and material scientists can utilize the mechanical properties data to develop structurally robust and flexible materials. (c) 2024 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license ( http://creativecommons.org/licenses/by/4.0/ )

Staphylococcus aureus is a major pathogen associated with important diseases in humans and animals. Macrophages represent an important component of the innate immune response that play a keys role in S. aureus infection outcome. In order to investigate the adaptive evolution of S. aureus in response to macrophages, we developed an experimental infection assay. S. aureus strains representing major human epidemic clones were passaged many times in a macrophage cell line, accumulating mutations in an array of genomic loci. This BioProject contains the read data (Illumina) for all sequenced passages, and long read data (PacBio) for selected passages of interest.

Este estudio analiza la contaminación microbiológica en las superficies internas de una ambulancia de la Empresa MDT en Riobamba. Utilizando una metodología transversal y cuantitativa, se recolectaron muestras microbiológicas de superficies clave (volante, manija de puerta, asiento de paramédico, piso del habitáculo, camilla y equipo de signos vitales) mediante hisopos estériles. Los resultados revelan la presencia de Escherichia coli en el volante y de Staphylococcus aureus y Staphylococcus epidermidis en otras superficies, con variabilidad significativa en las Unidades Formadoras de Colonias (UFC). Estos hallazgos subrayan la necesidad de reforzar las prácticas de higiene personal y de limpieza en áreas de alto contacto. La prevalencia de enfermedades en Riobamba incluye infecciones respiratorias, enfermedades crónicas como diabetes e hipertensión, problemas gastrointestinales y enfermedades cutáneas. La identificación y cuantificación específicas de los microorganismos proporcionan datos cruciales para mejorar las prácticas de desinfección y contribuir a la seguridad del personal y los pacientes en las ambulancias. Este estudio resalta la importancia de controlar la contaminación microbiológica en entornos prehospitalarios para prevenir infecciones nosocomiales y mejorar las condiciones sanitarias del transporte de emergencia. Se sugieren futuras investigaciones en otros tipos de vehículos de emergencia para obtener datos más representativos y evaluar el impacto de diferentes protocolos de limpieza.

Udder inflammation, also known as mastitis, is a major problem in dairy cows due to lower milk production, treatment costs, culling and damage to welfare. Mastitis is mainly caused by bacterial infections, of which Staphylococcus aureus is a common species. This bacterium, an opportunistic pathogen often present in the microbiota, can cause several diseases in addition to mastitis in many different animal species. Strains of S. aureus show great variability, they can be grouped into clonal complexes (CCs). It is known that strains from different CCs vary in properties, for example the preferred host and whether they occur mainly in the udder or in other sites. Current control measures are largely based on biosecurity and antibiotic treatment, but their effectiveness is limited, mainly due to the diversity of strains. Therefore, the aim of this thesis was to investigate the effect of strain differences on the epidemiology of S. aureus mastitis and to develop better control measures, such as vaccination, against S. aureus mastitis in dairy cattle. Results from a stochastic bioeconomic simulation model showed that removal of infected cows was the most effective measure for all strains, with lower incidence of intra-mammary infections (IMI), fewer treatment days and higher net income than other measures based on antibiotic treatment. Other measures showed a strain-dependent effect, where for example the spill-over strain, which has a source outside the udder, was less sensitive to certain measures than other strains. Body sites can be a source of S. aureus mastitis, especially the hock of cows is often colonized. In dairy goats, the nose in particular appeared to be colonized, which shows that colonization patterns differ between animal species. These insights may help in the development of specific measures to control S. aureus mastitis on different farms and in different animal species. The use of wall teichoic acid (WTA), a cell wall specific sugar structure, as a po

Available face masks, used to protect the respiratory system from various types of pathogens, show unsatisfactory efficiency because the size of viruses like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is much smaller than the void spaces in these masks. Difficult breathing through some masks quickly tires out, which makes ordinary people avoid wearing them. These facts suggest that a new strategy is desirable for designing protective face masks. The aim of the study was to present new filters for face masks to protect people exposed to high concentrations of bacteria and viruses, particularly SARS-CoV-2. Methods. Filters for these masks were manufactured of dense cotton fabric impregnated with silver quantum dots. The filters were characterized by scanning electron microscopy and ion-coupled plasma mass spectrometry. Wettability properties were determined by measuring contact angles with water, and a color fastness test was performed. Antibacterial assay was performed using Staphylococcus (S.) aureus. Viability quantitative polymerase chain reaction (qPCR) for virus integrity assay and reverse transcription qPCR (RT-qPCR) assay were used for antiviral activity assessment. Results. In vitro assays showed extremely high efficiency of these filters in destroying S. aureus and SARS-CoV-2 virus. The filters also showed high safety and easy breathing possibilities. Conclusion. The high efficiency of these masks against SARS-CoV-2 has been demonstrated through numerous tests, and they have been approved as anti-SARS-CoV-2 masks for the first time in the world. In the meantime, this solution has been applied in practice, and the data obtained about that are very encouraging.

Depto. de Medicina, Fac. de Medicina, TRUE, pub

The aim of the study was to explore the structure and growth dynamics of Staphylococcus aureus resistant to methicillin (MRSA) colonies using semithin sections visualized by light microscope. One S. aureus susceptible to methicillin (MSSA) and one MRSA clinical strains were studied. Colonies in agar plates were embedded in epoxy resin after each incubation period (24 h and 48 h) at 37 degrees . Semithin sections of 0.5 µm were stained with toluidine blue and visualized by light microscope. Microscopically, no structural differences were observed between SASM and SARM colonies but differences were observed in both strains between 24 and 48 h incubation periods. Colonies showed two layers clearly differentiated at 24 h independently of the resistance to methicillin: (A) one basal layer with high density of population in contact with culture media, and (B) one superficial layer with a lower density of population. Colonies showed four layers at 48 h: (A) one basal layer with high density of population; (B) one clear layer constituted by very degraded bacterial remains in which can be observed cocci dispersed with their dyeing properties; (C) one mixed layer constituted by viable bacteria and little degraded bacterial remains (D) one superficial layer with a lower density of population than basal layer. Colonial architecture is a complex and time-dependent process., Depto. de Medicina, Fac. de Medicina, TRUE, pub