Antibacterial effect of Asphodelus fistulosus aqueous and ethanolic crude extracts on gram positive and gram negative bacteria / Efeito antibacteriano de extratos brutos aquosos e etanólicos de Asphodelus fistulosus sobre bactérias gram-positivas e gram-negativas

Asphodelus fistulosus (A. fistulosus) is a wild plant grows in Jordan. Traditionally, it is used to treat different medical conditions and diseases such as respiratory ailments, against burns and dermatomucosal infections.This study aims to find out the effects of A. fistulosus aqueous and ethanolic crude extracts on Staphylococcus aureus(S. aureus) as gram positive bacteria and Escherichia coli (E. coli) as gram negative bacteria and to investigate which one will be affected either by aqueous and/or ethanolic crude extracts of A. fistulosus shooting parts that were collected from Jerash in the north of Jordan. Agar well diffusion method was used to evaluate the antibacterial activity of the crude extracts. In addition, MIC (minimum inhibitory concentration) as well as MBC (minimum bactericidal concentration) were determined against both types of bacteria. The results showed that flower aqueous extract of A. fistulosus was very effective against E. coli (20.0 ± 0.50) mm and caused a (14.0 ± 0.50) mm inhibition to S. aureus. The ethanolic extract of stem was very effective cauesed a (19.0 ± 0.50) mm inhibition in both bacterial species. Respectively, both S. aureus and E. coli were inhibited by ethanolic and aqueous extracts (mixture1 and mixture2) (15.0 ± 0.00 mm and 10.5 ± 0.50 mm). The highest antimbacterial activity was observed for the leaves aqueous extract against E.coli (0.06120 mg/mL). The obtained MIC values from A. fistulosus parts extracts demonstrated antibacterial activity ranged between 7.606 and 0.06120 mg/mL. The highest antimicrobial activity was recorded in the leaves aqueous extract against E. coli.The MBC value of stem aqueous extract was 5.00 mg/mL against both S. aureus and E. coli. On the other hand, ethanolic and aqueous extracts of the leaves gave MBC values 5.00 mg/mL, and 0.156 mg/mL, respectively, against E. coli.Based on the results of this study, it can be concluded that there is good inhibitory effect of aqueous and ethanolic of A. fistulosus shooting parts extracts on growth of E. coli and S. aureus. Adding to that, stem ethanolic extract has the most effective against S. aureus while aqueous extract of flower has the most effective against E. coli.So, it is recommended to have further future studies on the A. fistulosus shooting parts crude extract bioactive components and the mechanism of how these constituents affect these types of bacteria.

Asphodelus fistulosus (A. fistulosus) é uma planta selvagem que cresce na Jordânia. Tradicionalmente, é usada para tratar diferentes condições médicas e doenças, como doenças respiratórias, contra queimaduras e infecções dermatomucosas. Bactérias positivas e Escherichia coli (E. coli) como bactérias gram-negativas e investigar qual delas será afetada por extratos brutos aquosos e/ou etanólicos de partes de tiro de A. fistulosus que foram coletadas em Jerash no norte da Jordânia. O método de difusão em poço de ágar foi utilizado para avaliar a atividade antibacteriana dos extratos brutos. Além disso, MIC (concentração inibitória mínima) e MBC (concentração bactericida mínima) foram determinados contra ambos os tipos de bactérias. Os resultados mostraram que o extrato aquoso de flores de A. fistulosus foi muito eficaz contra E. coli (20,0 + 0,50 mm) e causou uma inibição (14,0 + 0,50 mm) para S. aureus. O extrato etanólico do caule foi muito eficaz, causando inibição (19,0 + 0,50 mm) em ambas as espécies bacterianas. Respectivamente, tanto S. aureus quanto E. coli foram inibidos pelos extratos etanólico e aquoso (mistura 1 e mistura 2) (15,0 + 0,00 mm e 10,5 + 0,50 mm). A maior atividade antibacteriana foi observada para o extrato aquoso das folhas contra E. coli (0,06120 mg/mL). Os valores de CIM obtidos dos extratos de partes de A. fistulosus demonstraram atividade antibacteriana variando entre 7,606 e 0,06120 mg/mL. A maior atividade antimicrobiana foi registrada no extrato aquoso das folhas contra E. coli. O valor de CBM do extrato aquoso do caule foi de 5,00 mg/mL contra S. aureus e E. coli. Por outro lado, os extratos etanólico e aquoso das folhas apresentaram valores de CBM de 5,00 mg/mL e 0,156 mg/mL, respectivamente, contra E. coli, efeito de extratos aquosos e etanólicos de partes de tiro de A. fistulosus no crescimento de E. coli e S. aureus. Somando-se a isso, o extrato etanólico do caule é o mais eficaz contra S. aureus enquanto o extrato aquoso da flor é o mais eficaz contra E. coli. Assim, recomenda-se a realização de estudos futuros sobre os componentes bioativos do extrato bruto de partes fotografais de A. fistulosus e o mecanismo de como esses constituintes afetam esses tipos de bactérias.

Poor outcome after debridement and implant retention for acute hematogenous periprosthetic joint infection: a cohort study of 43 patients.

BACKGROUND AND PURPOSE: The management of acute hematogenous periprosthetic joint infection (AHI) is challenging and the optimal treatment is not clearly defined. The aim of this study was to evaluate the treatment outcome of AHI, and secondarily to investigate potential risk factors that affect outcome. PATIENTS AND METHODS: We retrospectively analyzed 43 consecutive AHIs in a total hip or knee arthroplasty between 2013 and 2020 at a single center. We used the Delphi international consensus criteria to define infection. Patients were treated by either debridement, antibiotics, and implant retention (DAIR) (n = 25), implant exchange/removal (n = 15), or suppressive antibiotics only (n = 3). AHI was defined as abrupt symptoms of infection ≥ 3 months after implantation in an otherwise well-functioning arthroplasty. RESULTS: AHI was most often caused by Staphylococcus aureus (16/43) and streptococcal species (13/43), but a broad spectrum of microbes were identified. 25 of 43 were treated with DAIR, with success in 10 of 25, which was significantly lower than in patients treated with removal of the implant with success in 14 of 15. S. aureus infection, knee arthroplasty, and implant age < 2 years were associated with treatment failure. The 2-year mortality rate was 8 of 43. CONCLUSION: The outcome following DAIR in AHIs was poor. The majority of infections were caused by virulent microbes, and we found a high mortality rate. Removal of the implant should more often be considered.

Novel recombinant endolysin ointment with broad antimicrobial activity against methicillin-resistant Staphylococcus aureus isolated from wounds and burns.

The major problem in the management of burn wounds is infections. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the major causes of infection in burn wounds. Antibiotic-resistant bacteria around the world have become a major therapeutic challenge. Bacteriophages and their lysin are suggested as an antimicrobial alternative agent. The approach of this study was to evaluate the potential of recombinant phage lysin ointment efficacy in MRSA burn wound infection in vitro. Whole genome sequencing was performed to the three isolated bacteriophages by ABM, USA using Illumina next-generation sequencing (NGS) technology. De novo assembly and genetic analysis carried out. Expression of lysin genes was performed by cloning using Escherichia coli JM109. Lysin protein extraction and purification was performed before and after cloning using precipitation by ammonium sulfate, dialysis, and gel filtration chromatography. Dose-dependent assay and time-kill curve experiment was performed for 2 lysins showed that recombinant lysin 2 functions more than its non-recombinant lysins 2 with the same concentration of 0.5 µg/mL. Both lysins' ointment was prepared and compared with commercial ointments. 62 (78.4%) out of 79 wounds a burns swabs were detected as S. aureus and S methicillin-resistant S. aureus (MRSA) rate was determined to be 29 (46.8%) in total, while 33 isolates (53.2%) determined as methicillin-sensitive S. aureus (MSSA). According to the antibiotic susceptibility test results, all S. aureus isolates were identified as sensitive against vancomycin, ceftaroline, and linezolid. Results shows one lysogenic bacteriophage and three distinct lytic specific S. aureus bacteriophage were isolated from sewage. For each of the three samples, a single contig was possible to be obtained. Sample BP-SA2 had the best coverage, and the contig was slightly longer than the other bacteriophages. In addition, BLAST search identified Staphylococcus bacteriophage vB-SscM-1 (accession KX171212.1) as the closest match to the public database. Finally, the gene annotation was checked, and two potential lysin genes were identified. Besides the two ends, there are only 4 SNPs between the three genomes. It should be noted that the two lysin genes from the genomes have no SNPs, and are identical across the three genomes. It can be seen that the three bacteriophages (BP-SA1), (BP-SA 2), and (BP-SA3) form their own tight cluster. It can be seen that (BP-SA 2) is more closely related to Staphylococcus bacteriophage vB-SscM-1 genome and most noticeable 5' region of S5 and vB-SscM-1 are now located at 3' end of vB-Sau-Clo6. The investigation of the two lysin genes in (BP-SA 2) by whole genome sequencing showed that there is some homology with vB-SscM-1; although the first gene is annotated as hypothetical protein, the second gene is annotated as amidase. The same two lysin genes are identified in all three bacteriophage genomes by the RAST. The putative protein sequences of the discovered phage lysin was analyzed using protein search with UniProt/Swiss-Prot database, and all matches suggest that the putative protein of the discovered phage lysin is a real endolysin. The three samples of bacteriophage were harboring both (Lysin 1 and lysin 2) genes were amplified. Afterward, 2-lysin genes were cloned successfully; for the dose-dependent assay, the same incubation time of recombinant lysins and its two non-recombinant lysins with the bacteria for 30 min. It is found that the bactericidal activity of these groups increased in correlation with their concentrations. For the time-kill curve experiment, it showed that Recombinant lysin 2 functions more than its non-recombinant lysins 2 with the same concentration of 0.5 µg/mL. Both lysins' ointments have potential activity against S. aureus isolates more than mupirocin and have a similar activity with Fusidic acid through applying 10 µL from lysin 1 ointment, lysin 2 ointment, mupirocin ointment 2%, and Fusidic acid cream 2%. In vitro lytic spectrum analysis revealed that 100% (29/29) tested S. aureus were sensitive. One dose of lysin ointment resulted in a reduction of 3.3 log units in the number of bacteria (from an initial count of 2 × 105 CFU/mg) at 18 hours compared with one dose of mupirocin, PBS, or Aquaphor. Specifically, this study provides evidence that the application of lysin ointment has significant potential as an alternative strategy for MRSA infections.

In silico molecular modeling of cold pressed garden cress (Lepidium sativum L.) seed oil toward the binding pocket of antimicrobial resistance Staphylococcus aureus DNA-gyrase complexes.

OBJECTIVE: The seeds of garden cress, Lepidium sativum L., are a fantastic source of phytochemicals and proteins. The purpose of the current study was to use solvent extraction techniques to examine the physicochemical characteristics and biological activities of garden cress (L. sativum) seed oil extracts and compounds against Staphylococcus aureus, in vitro, molecular docking and pharmacokinetics. MATERIALS AND METHODS: Cress seed oil were collected from Sakaka, Saudi Arabia's Al-Jouf market. Seeds were crushed in 80% ethanol for several extraction. The oil extraction was forced through a perforated tube, and the meal was expelled via a calibrated aperture. After that, a centrifuge was used to separate the oil from the plant debris (15 min). Study the anti- Staphylococcus aureus of cress seed oil by Well-Diffusion Assay, while cress oil molecules docked against Staphylococcus aureus target (pdb-id: 2XCS) by MOE 19.0901 Software. The pharmacokinetics (ADMET) and Lipinski's rules were predicted by pKCSM online server (available at: https://biosig.lab.uq.edu.au/pkcsm/prediction). RESULTS: The outcome showed that the oil yield for seed oil extract, the specific gravity (0.93) and concentration (33%) was substantially greater. Our findings included a maximal zone of inhibition (23 mm), a minimum inhibitory concentration (MIC) of 80 µg/mL, and a minimum bactericidal concentration (MBC) of 170 µg/mL of cress oil against Staphylococcus aureus. The docking results indicated that the affinity score of Quercetin-3-O-glucosylgalactoside docked against pdb-id: 2XCS was 9.48, while RMSD 1.59 Å compared with the co-crystallized ligand showed an affinity score of -7.58 kcal/mol and RMSD 1.32 Å. CONCLUSIONS: Our findings suggest that Cress seed oil might be utilised to protect food from S. aureus infection that is resistant to antibiotics.

Phytochemical Composition and Antimicrobial Activity of Essential Oil from the Leaves of Artemisia vulgaris L.

Artemisia vulgaris is an enormously useful aromatic plant known for its insecticidal, antifungal, parasiticidal, and medicinal values. The main aim of this study is to investigate phytochemical contents and the potential antimicrobial activities of Artemisia vulgaris essential oil (AVEO) from the fresh leaves of A. vulgaris grown in Manipur. The AVEO isolated by hydro-distillation from A. vulgaris were analyzed by gas chromatography/mass spectrometry and solid-phase microextraction-GC/MS to describe their volatile chemical profile. There were 47 components identified in the AVEO by GC/MS, amounting to 97.66% of the total composition, while 97.35% were identified by SPME-GC/MS. The prominent compounds present in AVEO analyzed by direct injection and SPME methods are found to be eucalyptol (29.91% and 43.70%), sabinene (8.44% and 8.86%), endo-Borneol (8.24% and 4.76%), 2,7-Dimethyl-2,6-octadien-4-ol (6.76% and 4.24%), and 10-epi-γ-Eudesmol (6.50% and 3.09%). The consolidated component in the leaf volatiles comes to the terms of monoterpenes. The AVEO exhibits antimicrobial activities against fungal pathogens such as Sclerotium oryzae (ITCC 4107) and Fusarium oxysporum (MTCC 9913) and bacterial cultures such as Bacillus cereus (ATCC 13061) and Staphylococcus aureus (ATCC 25923). The percent inhibition of AVEO against the S. oryzae and F. oxysporum was found up to 50.3% and 33.13%, respectively. The MIC and MBC of the essential oil tested for B. cereus and S. aureus were found to be (0.3%, 0.63%) and (0.63%, 2.5%), respectively. Finally, the results revealed that the AVEO characterized by the hydro-distillation and SPME extraction yielded the same chemical profile and showed potent antimicrobial activities. Further research into A. vulgaris's antibacterial properties can be performed in order to use it as a source for natural antimicrobial medications.

Green Synthesis of Silver Nanoparticles from Allium cepa L. Peel Extract, Their Antioxidant, Antipathogenic, and Anticholinesterase Activity.

The present work deals with the green synthesis and characterization of silver nanoparticles (AgNPs) using Allium cepa (yellowish peel) and the evaluation of its antimicrobial, antioxidant, and anticholinesterase activities. For the synthesis of AgNPs, peel aqueous extract (200 mL) was treated with a 40 mM AgNO3 solution (200 mL) at room temperature, and a color change was observed. In UV-Visible spectroscopy, an absorption peak formation at ~439 nm was the sign that AgNPs were present in the reaction solution. UV-vis, FE-SEM, TEM, EDX, AFM, XRD, TG/DT analyses, and Zetasizer techniques were used to characterize the biosynthesized nanoparticles. The crystal average size and zeta potential of AC-AgNPs with predominantly spherical shapes were measured as 19.47 ± 1.12 nm and -13.1 mV, respectively. Pathogenic microorganisms Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were used for the Minimum Inhibition Concentration (MIC) test. When compared to tested standard antibiotics, AC-AgNPs demonstrated good growth inhibitory activities on P. aeuruginosa, B. subtilis, and S. aureus strains. In vitro, the antioxidant properties of AC-AgNPs were measured using different spectrophotometric techniques. In the ß-Carotene linoleic acid lipid peroxidation assay, AC-AgNPs showed the strongest antioxidant activity with an IC50 value of 116.9 µg/mL, followed by metal-chelating capacity and ABTS cation radical scavenging activity with IC50 values of 120.4 µg/mL and 128.5 µg/mL, respectively. The inhibitory effects of produced AgNPs on the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were determined using spectrophotometric techniques. This study provides an eco-friendly, inexpensive, and easy method for the synthesis of AgNPs that can be used for biomedical activities and also has other possible industrial applications.

Construction of a dynamic model to predict the growth of Staphylococcus aureus and the formation of enterotoxins during Kazak cheese maturation.

Staphylococcus aureus is a common pathogen found in cheese whose Staphylococcal enterotoxins (SE) are the main pathogenic factors that cause food poisoning. The objective of this study was to construct two models to evaluate the safety of Kazak cheese products in terms of composition, changes in S. aureus inoculation amount, Aw, fermentation temperature during processing, and growth of S. aureus in the fermentation stage. A total of 66 experiments comprised of five levels of inoculation amount (2.7-4 log CFU/g), five levels of Aw (0.878-0.961), and six levels of fermentation temperature (32-44 °C) were performed to confirm the growth of S. aureus and the presence of SE limit conditions. Two artificial neural networks (ANN) successfully described the relationship between the assayed conditions and the growth kinetic parameters (maximum growth rates and lag times) of the strain. The good fitting accuracy (R2 values were 0.918 and 0.976, respectively) showed that the ANN was appropriate. Experimental results showed fermentation temperature had the greatest influence on the maximum growth rate and lag time, followed by the Aw and inoculation amount. Furthermore, a probability model was built to predict the production of SE by logistic regression and neural network under the assayed conditions, which proved to be concordant in 80.8-83.8% of the cases with the observed probabilities. The maximum total number of colonies predicted by the growth model in all combinations detected with SE exceeded 5 log CFU/g. Within the range of variables, the minimum Aw for predicting SE production was 0.938, and the minimum inoculation amount for predicting SE production was 3.22 log CFU/g. Additionally, as competition between S. aureus and lactic acid bacteria (LAB) occurs in the fermentation stage, higher fermentation temperatures are conducive to the growth of LAB, which can reduce the risk of S. aureus producing SE. This study can help manufacturers to make decisions on the most appropriate production parameters for Kazak cheese products and to prevent S. aureus growth and SE production.

Citral and trans-cinnamaldehyde, two plant-derived antimicrobial agents can induce Staphylococcus aureus into VBNC state with different characteristics.

Viable but nonculturable (VBNC) state bacteria are difficult to detect in the food industry due to their nonculturable nature and their recovery characteristics pose a potential threat to human health. The results of this study indicated that S. aureus was found to enter the VBNC state completely after induced by citral (1 and 2 mg/mL) for 2 h, and after induced by trans-cinnamaldehyde (0.5 and 1 mg/mL) for 1 h and 3 h, respectively. Except for VBNC state cells induced by 2 mg/mL citral, the VBNC state cells induced by the other three conditions (1 mg/mL citral, 0.5 and 1 mg/mL trans-cinnamaldehyde) were able to be resuscitated in TSB media. In the VBNC state cells induced by citral and trans-cinnamaldehyde, the ATP concentration was reduced, the hemolysin-producing ability was significantly decreased, but the intracellular ROS level was elevated. The results of heat and simulated gastric fluid experiments showed different environment resistance on VBNC state cells induced by citral and trans-cinnamaldehyde. In addition, by observing the VBNC state cells showed that irregular folds on the surface, increased electron density inside and vacuoles in the nuclear region. What's more, S. aureus was found to enter the VBNC state completely after induced by meat-based broth containing citral (1 and 2 mg/mL) for 7 h and 5 h, after induced by meat-based broth containing trans-cinnamaldehyde (0.5 and 1 mg/mL) for 8 h and 7 h. In summary, citral and trans-cinnamaldehyde can induce S. aureus into VBNC state and food industry needs to comprehensively evaluate the antibacterial capacity of these two plant-derived antimicrobial agents.

Dose optimization in surgical prophylaxis: sub-inhibitory dosing of vancomycin increases rates of biofilm formation and the rates of surgical site infection.

Antibiotic stewardship is viewed as having great public health benefit with limited direct benefit to the patient at the time of administration. The objective of our study was to determine if inappropriate administration of antibiotics could create conditions that would increase the rates of surgical infection. We hypothesized that sub-MIC levels of vancomycin would increase Staphylococcus aureus growth, biofilm formation, and rates of infection. S. aureus MRSA and MSSA strains were used for all experiments. Bacteria were grown planktonically and monitored using spectrophotometry. Quantitative agar culture was used to measure planktonic and biofilm bacterial burden. A mouse abscess model was used to confirm phenotypes in vivo. In the planktonic growth assay, increases in bacterial burden at » MIC vancomycin were observed in USA300 JE2 by 72 h. Similar findings were observed with ½ MIC in Newman and SH1000. For biofilm formation, USA300 JE2 at » and ½ MIC vancomycin increased biofilm formation by approximately 1.3- and 2.3-fold respectively at 72 h as compared to untreated controls. Similar findings were observed with Newman and SH1000 with a 2.4-fold increase in biofilm formation at ½ MIC vancomycin. In a mouse abscess model, there was a 1.2-fold increase with sub-MIC vancomycin at 3 days post infection. Our study showed that Sub-optimal vancomycin dosing promoted S. aureus planktonic growth and biofilm formation, phenotypic measures of bacterial virulence. This phenotype induced by sub-MIC levels of vancomycin was also observed to increase rates of infection and pathogenesis in our mouse model. Risks of exposure to sub-MIC concentrations with vancomycin in surgical procedures are greater as there is decreased bioavailability in tissue in comparison to other antibiotics. This highlights the importance of proper antibiotic selection, stewardship, and dosing for both surgical prophylaxis and treatment of infection.

High-force catch bonds between the Staphylococcus aureus surface protein SdrE and complement regulator factor H drive immune evasion.

The invasive bacterial pathogen Staphylococcus aureus recruits the complement regulatory protein factor H (fH) to its surface to evade the human immune system. Here, we report the identification of an extremely high-force catch bond used by the S. aureus surface protein SdrE to efficiently capture fH under mechanical stress. We find that increasing the external force applied to the SdrE-fH complex prolongs the lifetime of the bond at an extraordinary high force, 1,400 pN, above which the bond lifetime decreases as an ordinary slip bond. This catch-bond behavior originates from a variation of the dock, lock and latch interaction, where the SdrE ligand binding domains undergo conformational changes under stress, enabling the formation of long-lived hydrogen bonds with fH. The binding mechanism dissected here represents a potential target for new therapeutics against multidrug-resistant S. aureus strains.

Staphylococcus aureus Cell Wall Phenotypic Changes Associated with Biofilm Maturation and Water Availability: A Key Contributing Factor for Chlorine Resistance.

Staphylococcus aureus biofilms are resistant to both antibiotics and disinfectants. As Staphylococci cell walls are an important defence mechanism, we sought to examine changes to the bacterial cell wall under different growth conditions. Cell walls of S. aureus grown as 3-day hydrated biofilm, 12-day hydrated biofilm, and 12-day dry surface biofilm (DSB) were compared to cell walls of planktonic organisms. Additionally, proteomic analysis using high-throughput tandem mass tag-based mass spectrometry was performed. Proteins involved in cell wall synthesis in biofilms were upregulated in comparison to planktonic growth. Bacterial cell wall width (measured by transmission electron microscopy) and peptidoglycan production (detected using a silkworm larva plasma system) increased with biofilm culture duration (p < 0.001) and dehydration (p = 0.002). Similarly, disinfectant tolerance was greatest in DSB, followed by 12-day hydrated biofilm and then 3-day biofilm, and it was least in the planktonic bacteria--suggesting that changes to the cell wall may be a key factor for S. aureus biofilm biocide resistance. Our findings shed light on possible new targets to combat biofilm-related infections and hospital dry surface biofilms.

Fabrication and Evaluation of Polyvinyl Alcohol/Corn Starch/Patchouli Oil Hydrogel Films Loaded with Silver Nanoparticles Biosynthesized in Pogostemon cablin Benth Leaves' Extract.

Research on the manufacture of hydrogel films from polyvinyl alcohol, corn starch, patchouli oil, and silver nanoparticles, (PVA/CS/PO/AgNPs, respectively) was completed. The silver nanoparticles used in this study resulted from green synthesis using local patchouli plants (Pogostemon cablin Benth). Aqueous patchouli leaf extract (APLE) and methanol patchouli leaf extract (MPLE) are used in the synthesis of phytochemicals (green synthesis), which are then blended in the production of PVA/CS/PO/AgNPs hydrogel films, which are then cross linked with glutaraldehyde. The results demonstrated that the hydrogel film was flexible, easy to fold, and free of holes and air bubbles. The presence of hydrogen bonds between the functional groups of PVA, CS, and PO was revealed using FTIR spectroscopy. SEM analysis revealed that the hydrogel film was slightly agglomerated and did not exhibit cracking or pinholes. The analysis of pH, spreadability, gel fraction, and swelling index showed that the resulting PVA/CS/PO/AgNP hydrogel films met expected standards except for the organoleptic properties of the resulting colors, which tended to be slightly darker in color. The formula with silver nanoparticles synthesized in methanolic of patchouli leaf extract (AgMENPs) had the highest thermal stability compared to hydrogel films with silver nanoparticles synthesized in aqueous of patchouli leaf extract (AgAENPs). The hydrogel films can be safely used up to 200 °C. The antibacterial studies revealed that the films inhibited the growth of both Staphylococcus aureus and Staphylococcus epidermis, as determined by the disc diffusion method, with the best antibacterial activity being against Staphylococcus aureus. In conclusion, the hydrogel film F1, loaded with silver nanoparticles biosynthesized in aqueous of patchouli leave extract (AgAENPs) and light fraction of patchouli oil (LFoPO) performed the best activity against both Staphylococcus aureus and Staphylococcus epidermis.

Enhancing the Antimicrobial Effect of Ozone with Mentha piperita Essential Oil.

This study aimed to obtain and analyse Mentha piperita essential oil (MpEO) for the prospect of being used as an enhancement agent for the antimicrobial potential of ozone against gram-positive and gram-negative bacteria and fungi. The research was done for different exposure times, and it gained time-dose relationships and time-effect correlations. Mentha piperita (Mp) essential oil (MpEO) was obtained via hydrodistillation and further analysed by using GC-MS. The broth microdilution assay was used to determine the strain inhibition/strain mass growth by using spectrophotometric optical density reading (OD). The bacterial/mycelium growth rates (BGR/MGR) and the bacterial/mycelium inhibition rates (BIR/MIR) after ozone treatment in the presence and absence of MpEO on the ATTC strains were calculated; the minimum inhibition concentration (MIC) and statistical interpretations of the time-dose relationship and specific t-test correlations were determined. The effect of ozone on the following tested strains at maximum efficiency was observed after 55 s of single ozone exposure, in order of effect strength: S. aureus > P. aeruginosa > E. coli > C. albicans > S. mutans. For ozone with the addition of 2% MpEO (MIC), maximum efficacy was recorded at 5 s for these strains, in order of effect strength: C. albicans > E. coli > P. aeruginosa > S. aureus > S. mutans. The results suggest a new development and affinity regarding the cell membrane of the different microorganisms tested. In conclusion, the use of ozone, combined with MpEO, is sustained as an alternative therapy in plaque biofilm and suggested as helpful in controlling oral disease-causing microorganisms in medicine.

Sulfonamide Porphyrins as Potent Photosensitizers against Multidrug-Resistant Staphylococcus aureus (MRSA): The Role of Co-Adjuvants.

Sulfonamides are a conventional class of antibiotics that are well-suited to combat infections. However, their overuse leads to antimicrobial resistance. Porphyrins and analogs have demonstrated excellent photosensitizing properties and have been used as antimicrobial agents to photoinactivate microorganisms, including multiresistant Staphylococcus aureus (MRSA) strains. It is well recognized that the combination of different therapeutic agents might improve the biological outcome. In this present work, a novel meso-arylporphyrin and its Zn(II) complex functionalized with sulfonamide groups were synthesized and characterized and the antibacterial activity towards MRSA with and without the presence of the adjuvant KI was evaluated. For comparison, the studies were also extended to the corresponding sulfonated porphyrin TPP(SO3H)4. Photodynamic studies revealed that all porphyrin derivatives were effective in photoinactivating MRSA (>99.9% of reduction) at a concentration of 5.0 µM upon white light radiation with an irradiance of 25 mW cm-2 and a total light dose of 15 J cm-2. The combination of the porphyrin photosensitizers with the co-adjuvant KI during the photodynamic treatment proved to be very promising allowing a significant reduction in the treatment time and photosensitizer concentration by six times and at least five times, respectively. The combined effect observed for TPP(SO2NHEt)4 and ZnTPP(SO2NHEt)4 with KI seems to be due to the formation of reactive iodine radicals. In the photodynamic studies with TPP(SO3H)4 plus KI, the cooperative action was mainly due to the formation of free iodine (I2).

Sortase A Inhibitor Protein Nanoparticle Formulations Demonstrate Antibacterial Synergy When Combined with Antimicrobial Peptides.

Sortase A (SrtA) is an enzyme which attaches proteins, including virulence factors, to bacterial cell walls. It is a potential target for developing anti-virulence agents against pathogenic and antimicrobial resistant bacteria. This study aimed to engineer 𝛽-lactoglobulin protein nanoparticles (PNPs) for encapsulating safe and inexpensive natural SrtA inhibitors (SrtAIs; trans-chalcone (TC), curcumin (CUR), quercetin (QC), and berberine (BR)) to improve their poor aqueous dispersibility, to screen for synergy with antimicrobial peptides (AMPs), and to reduce the cost, dose, and toxicity of AMPs. Minimum inhibitory concentration (MIC), checkerboard synergy, and cell viability assays were performed for SrtAI PNPs against Gram-positive (methicillin-sensitive and -resistant S. aureus) and Gram-negative (E. coli, P. aeruginosa) bacteria alone and combined with leading AMPs (pexiganan, indolicidin, and a mastoparan derivative). Each SrtAI PNP inhibited Gram-positive (MIC: 62.5-125 µg/mL) and Gram-negative (MIC: 31.3-500 µg/mL) bacterial growth. TC PNPs with pexiganan demonstrated synergy against each bacteria, while BR PNPs with pexiganan or indolicidin provided synergy towards S. aureus. Each SrtAI PNP inhibited SrtA (IC50: 25.0-81.8 µg/mL), and did not affect HEK-293 cell viability at their MIC or optimal synergistic concentrations with AMPs. Overall, this study provides a safe nanoplatform for enhancing antimicrobial synergy to develop treatments for superbug infections.

[Occurrence and resistance of bacteria isolated from the rabbit nares - a retrospective evaluation]. / Vorkommen und Resistenzen von Bakterien in Proben aus Kaninchennasen ­ eine retrospektive Auswertung.

OBJECTIVE: Rabbit snuffles is one of the most common challenges in veterinary practice. The aim of the present study was to evaluate nasal samples of rabbits submitted between 2015-2019, with regard to bacterial distribution and antimicrobial resistance. MATERIAL AND METHODS: Each sample was plated on four different agar plates and enriched in a non-selective broth. Isolates were identified by MALDI Biotyper® (MBT) (Bruker Daltonik GmbH, Bremen, Germany) and antimicrobial susceptibility was performed by broth microdilution method in accordance with the Clinical and Laboratory Standards Institute (CLSI, Wayne, PA, USA). RESULTS: A total of 1261 samples were evaluated. Among the samples that tested positive (n=941), one bacterial species was detected in 79.1% of the cases, and more than one bacterial species (mixed culture) was found in 20.9% of the cases. A total of 150 species from 14 families were identified. Isolates belonging to the family Pasteurellaceae were identified most frequently, followed by Enterobacteriaceae, Pseudomonadaceae and Staphylococcaceae.A total of 467 antibiograms of the most common pathogens with possible clinical relevance (Pasteurella multocida [14.6%], Pasteurella species [10.0%], Staphylococcus aureus [5.9%], Pseudomonas aeruginosa [5.4%] and Bordetella bronchiseptica [4.8%]) were evaluated. Quinolones showed the highest efficacy and clindamycin the lowest. Furthermore, among S. aureus, MRSA were most frequently detected in 2016 reaching 23.1% of cases. CONCLUSIONS AND CLINICAL RELEVANCE: Since the causal bacteria for rabbit snuffles are mostly found in the deeper areas of the nose and the nasal vestibule is often contaminated with ubiquitous and coliform bacteria, it would make sense to take samples from the depth of the nasal cavity, ideally via nasal lavage. Due to the demonstrated pathogen diversity and long-term therapy associated with the disease, bacterial culture and sensitivity testing is recommended as part of the management. In the absence of an antibiogram, enrofloxacin is the drug of first choice due to its favorable resistance pattern and tolerability. However, since quinolones are considered as "critically important" antibiotics, their use should be limited to a minimum.

Probable enterotoxin-associated toxic shock syndrome caused by Staphylococcus epidermidis.

BACKGROUND: We describe a case of a toxic shock-like syndrome in a child, which was associated with Staphylococcus epidermidis instead of Staphylococcus aureus or Streptococcus pyogenes, the usual causes of toxic shock syndrome. CASE PRESENTATION: The patient was an 8-year-old boy who developed a toxic shock syndrome-like illness, including fever, hypotension, and rash. The Staphylococcus epidermidis isolate was cultured from urine, but this organism was unavailable for toxin testing. Multiple blood cultures were negative. Instead, a highly novel assay was used on acute plasma from the patient which demonstrated the presence of the genes for superantigens, staphylococcal enterotoxins A, C, D, and E. Superantigens are the known causes of toxic shock syndrome. CONCLUSIONS: Our study suggests strongly that Staphylococcus epidermidis was causing the TSS symptoms through the known Staphylococcus aureus superantigens. It is unknown how many other such patients exist; this should be explored. Of great importance is that PCR performed directly on blood plasma in the absence of microbial isolation could be used to demonstrate superantigen genes.

Factors affecting the microbiological quality and contamination of farm bulk milk by Staphylococcus aureus in dairy farms in Asella, Ethiopia.

BACKGROUND: The determination of the microbiological quality and safety of raw milk and the associated influencing factors at the farm level is very critical given that the quality or safety of subsequent products that are further produced depends on this. Therefore, this study aimed to determine the microbiological quality and safety of bulk milk and identify associated risk factors, and assess the presence/absence of S. aureus in bulk milk with potential contaminating sources in dairy farms in Asella, Ethiopia. RESULTS: The geometric means of bacterial counts in farm bulk milk were 5.25 log cfu/ml, 3.1 log cfu/ml and 2.97 log cfu/ml for total bacterial count (TBC), coliform count (CC) and coagulase-positive staphylococci count (CPS), respectively. Of the 50 dairy farms, 66, 88, and 32% had TBC, CC and CPS counts, respectively, that exceeded the standard international limits for raw cow's milk intended for direct human consumption. TBC tended to increase as CC increased in bulk milk (r = 0.5). In the final regression model, increased TBC, CC and the contamination of farm bulk milk by S. aureus were significantly associated with dirty barns, dirty cows and soiled udder and teats. TBC was higher during the rainy season than during the dry season. The reported practice of washing teats with warm water significantly decreased CC and CPS. The occurrence of S. aureus was significantly (p < 0.05) higher in bulk farm milk (42%) than in pooled udder milk (37.3%), teat swabs (22.5%), milkers' hand swabs (18%), bulking bucket swabs (16.7%), milking container swabs (14%), and water for cleaning of udder and milkers' hands (10%). The questionnaire survey result showed widespred raw milk consumption habits, low level of training and poor hygienic milking practices. CONCLUSIONS: This study revealed low-quality bulk farm milk with high bacterial counts and a high occurrence of S. aureus. This indicates the potential food safety risks due to consumption of raw milk or its products. This study suggests awareness creation to dairy farmers and the public on hygienic milk production and heat treatment of milk before consumption.

Can platelet-rich fibrin act as a natural carrier for antibiotics delivery? A proof-of-concept study for oral surgical procedures.

OBJECTIVES: Evaluate the role of platelet-rich fibrin (PRF) as a natural carrier for antibiotics delivery through the analysis of drug release and antimicrobial activity. MATERIALS AND METHODS: PRF was prepared according to the L-PRF (leukocyte- and platelet-rich fibrin) protocol. One tube was used as control (without drug), while an increasing amount of gentamicin (0.25 mg, G1; 0.5 mg, G2; 0.75 mg, G3; 1 mg, G4), linezolid (0.5 mg, L1; 1 mg, L2; 1.5 mg, L3; 2 mg, L4), vancomycin (1.25 mg, V1; 2.5 mg, V2; 3.75 mg, V3; 5 mg, V4) was added to the other tubes. At different times the supernatant was collected and analyzed. Strains of E. coli, P. aeruginosa, S. mitis, H. influenzae, S. pneumoniae, S. aureus were used to assess the antimicrobial effect of PRF membranes prepared with the same antibiotics and compared to control PRF. RESULTS: Vancomycin interfered with PRF formation. Gentamicin and linezolid did not change the physical properties of PRF and were released from membranes in the time intervals examined. The inhibition area analysis showed that control PRF had slight antibacterial activity against all tested microorganisms. Gentamicin-PRF had a massive antibacterial activity against all tested microorganisms. Results were similar for linezolid-PRF, except for its antibacterial activity against E. coli and P. aeruginosa that was comparable to control PRF. CONCLUSIONS: PRF loaded with antibiotics allowed the release of antimicrobial drugs in an effective concentration. Using PRF loaded with antibiotics after oral surgery may reduce the risk of post-operative infection, replace or enhance systemic antibiotic therapy while preserving the healing properties of PRF. Further studies are needed to prove that PRF loaded with antibiotics represents a topical antibiotic delivery tool for oral surgical procedures.

Chitosan/Starch-Based Active Packaging Film with N, P-Doped Carbon Dots for Meat Packaging.

Nitrogen, phosphorus-doped green-tea-derived carbon dots (NP-CDs) incorporated chitosan/starch (Chi/St) based multifunctional nanocomposite films were prepared. FE-SEM images verified a homogeneous distribution of CDs with minimum aggregation in the fabricated films. Incorporating NP-CDs led to enhanced UV-light blocking (93.1% of UV-A and ∼99.7% of UV-B) without significantly affecting the films' water transparency and water vapor permeability. Besides, incorporating NP-CDs into the Chi/St films enhanced antioxidant activity (98.0% for ABTS and 71.4% for DPPH) and displayed strong antibacterial activity against L. monocytogenes, E. coli, and S. aureus. Wrapping the meat in the prepared film and storing it at 20 °C has been shown to reduce bacterial growth (less than 2.5 Log CFU/g after 48 h) without significantly altering the actual color of the wrapped meat. The Chi/St film loaded with NP-CD has high potential as an active packaging material to ensure safety and extend the shelf life of meat products.