Methicillin-resistant Staphylococcus Aureus ATCC Research Articles

MRSA Inhibitory Activity of Some New Pyrazolo[1,5-a]pyrimidines Linked to Arene and/or Furan or Thiophene Units.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major contributor to hospital-acquired infections and is highly resistant to treatment. Ongoing research focuses on developing new antimicrobial medications to prevent the spread of resistance. A facile method was employed to efficiently synthesize new pyrazolo[1,5-a]pyrimidines in 84-93% yields by reacting 4-benzyl-1H-pyrazole-3,5-diamine with the respective α,β-unsaturated ketones. The reaction was carried out in ethanol containing 1.2 equivalents of potassium hydroxide at reflux for 5-6 h. The new products are attached to a para-substituted aryl group with variable electronic properties at pyrazolopyrimidine-C5, in addition to one of three units at C7, namely phenyl, thiophen-2-yl, or furan-2-yl units. A wide spectrum of antibacterial activity was displayed by the new pyrimidines against six different bacterial strains. In general, pyrimidines attached to furan-2-yl units at C7, in addition to another aryl unit at C5, attached to 4-Me or 4-OMe groups, demonstrate significant antibacterial activity, particularly against S. aureus strain. They had MIC/MBC of 2.5/5.1 and 2.4/4.9 µM, respectively, which exceeded that of ciprofloxacin. Moreover, they demonstrate more effective MRSA inhibitory activity than linezolid, with MIC/MBC values up to 4.9/19.7 and 2.4/19.7 µM against MRSA ATCC:33591 and ATCC:43300 strains, respectively.

Synergistic interaction between Chlorella vulgaris extract and Origanum elongatum essential oil against methicillin-resistant Staphylococcus aureus.

The massive emergence of antimicrobial resistance in recent decades has rendered the use of a single-agent strategy ineffective. Consequently, the combination of different therapeutic agents has emerged as a promising new approach. The aim of the present study was to investigate the combined effect of Chlorella vulgaris methanol extract (CVME) and Origanum elongatum essential oil (OEEO) on methicillin-resistant Staphylococcus aureus (MRSA). Thus, the antibacterial activity of OEEO and CVME on Escherichia coli, Staphylococcus aureus, and MRSA was evaluated using the agar well diffusion and broth microdilution methods. The killing activity of CVME and OEEO, individually and in combination, on MRSA ATCC 43300 was tested using the time-kill assay. The synergistic effect was examined by determining the fractional inhibitory concentration index (FICI) using the checkerboard test. The results showed very significant antibacterial activity against all the bacteria tested, for both OEEO and CVME, with minimum inhibitory concentrations (MICs) ranging from 0.125 to 0.25% (v/v) for OEEO and from 3.12 to 6.25 mg mL-1 for CVME. Minimum bactericidal concentration (MBC) values for OEEO and CVME were in the range 0.125-0.5% (v/v) and 6.25-12.5 mg mL-1, respectively. The inhibition zones associated with OEEO were distinctly greater than those associated with CVME for all the bacteria examined. When used individually, the time-kill curves of OEEO and CVME revealed a dose-dependent effect on MRSA proliferation. Compared with controls, both agents were able to prolong the latent phase of growth curves and decelerate bacterial growth. The killing effect of OEEO on MRSA was considerably higher than that observed with CVME. OEEO prevented MRSA proliferation at only 1/2 of its MIC, while the CVME did so at 2 times its MIC. The combination of OEEO with CVME demonstrated a synergistic effect against MRSA, with a FIC index value of 0.49. The findings therefore suggest that the combination of C. vulgaris methanol extract and O. elongatum essential oil at very low doses may be promising anti-MRSA candidates. A search of the published literature revealed that, to our knowledge, no studies have yet been carried out on the antibacterial potential of combining essential oils and microalgae extracts in the fight against MRSA.

Evaluation of the Anti-MRSA Activity of Supercritical Carbon Dioxide and Macerated Crude Extracts of Padina spp. Collected from the Coastal Waters of Tacloban City, the Philippines

The World Health Organization classifies methicillin-resistant Staphylococcus aureus (MRSA) as a high priority in the pathogens list for research and development of new antibiotics. Natural compounds from brown algae are being studied for their potential as alternative sources of antibiotics, including Padina spp. This study aims to evaluate the anti-MRSA activity of the crude extracts obtained through supercritical carbon dioxide extraction (SCCO2) and maceration (MAC) of Padina spp. seaweeds from the coastal waters of Tacloban City, the Philippines. The evaluation of extracts for their anti-MRSA and anti-MSSA (methicillin-susceptible Staphylococcus aureus) activities was done via the resazurin microplate assay, and the Mann-Whitney U test was used to compare these activities. Results show that MAC exhibited minimum inhibitory concentrations (MIC) of 2,048–4,096 μg/mL and 512–4,096 μg/mL for SCCO2 for the MRSA and MSSA control and clinical isolates, respectively. While the MICs for the SCCO2 extracts were lower than those for the MAC extracts, no significant difference was found between the MICs of the extracts from the two extraction methods. No significant difference was observed between the MICs of the extracts against the MRSA (43300) and MSSA (25923) ATCC strains and clinical isolates. Finally, significant differences were observed between the MICs of the control antibiotics and both extraction methods.

Providing insight into the mechanism of action of cationic lipidated oligomers using metabolomics.

The increasing resistance of clinically relevant microbes against current commercially available antimicrobials underpins the urgent need for alternative and novel treatment strategies. Cationic lipidated oligomers (CLOs) are innovative alternatives to antimicrobial peptides and have reported antimicrobial potential. An understanding of their antimicrobial mechanism of action is required to rationally design future treatment strategies for CLOs, either in monotherapy or synergistic combinations. In the present study, metabolomics was used to investigate the potential metabolic pathways involved in the mechanisms of antibacterial activity of one CLO, C12-o-(BG-D)-10, which we have previously shown to be effective against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. The metabolomes of MRSA ATCC 43300 at 1, 3, and 6 h following treatment with C12-o-(BG-D)-10 (48 µg/mL, i.e., 3× MIC) were compared to those of the untreated controls. Our findings reveal that the studied CLO, C12-o-(BG-D)-10, disorganized the bacterial membrane as the first step toward its antimicrobial effect, as evidenced by marked perturbations in the bacterial membrane lipids and peptidoglycan biosynthesis observed at early time points, i.e., 1 and 3 h. Central carbon metabolism and the biosynthesis of DNA, RNA, and arginine were also vigorously perturbed, mainly at early time points. Moreover, bacterial cells were under osmotic and oxidative stress across all time points, as evident by perturbations of trehalose biosynthesis and pentose phosphate shunt. Overall, this metabolomics study has, for the first time, revealed that the antimicrobial action of C12-o-(BG-D)-10 may potentially stem from the dysregulation of multiple metabolic pathways.IMPORTANCEAntimicrobial resistance poses a significant challenge to healthcare systems worldwide. Novel anti-infective therapeutics are urgently needed to combat drug-resistant microorganisms. Cationic lipidated oligomers (CLOs) show promise as new antibacterial agents against Gram-positive pathogens like methicillin-resistant Staphylococcus aureus (MRSA). Understanding their molecular mechanism(s) of antimicrobial action may help design synergistic CLO treatments along with monotherapy. Here, we describe the first metabolomics study to investigate the killing mechanism(s) of CLOs against MRSA. The results of our study indicate that the CLO, C12-o-(BG-D)-10, had a notable impact on the biosynthesis and organization of the bacterial cell envelope. C12-o-(BG-D)-10 also inhibits arginine, histidine, central carbon metabolism, and trehalose production, adding to its antibacterial characteristics. This work illuminates the unique mechanism of action of C12-o-(BG-D)-10 and opens an avenue to design innovative antibacterial oligomers/polymers for future clinical applications.

Endophytic fungi of Tradescantia pallida mediated targeting of Multi-Drug resistant human pathogens

Antimicrobial resistance (AMR) has emerged as one of the most serious worldwide public health issues of the twenty-first century. The expeditious rise of AMR has urged the development of new, natural effective therapeutic strategies against drug-resistant pathogens. Endophytic fungi, which inhabit distinctive environments like endosymbiotic relationships with plants, are gaining interest as alternative reservoirs for novel compounds that exhibit a broad range of chemical diversity and unique modes of action by releasing a variety of secondary metabolites with antimicrobial properties. The objective of the current research was to isolate and identify endophytic fungal species from leaves of Tradescantia pallida and to investigate their antagonistic effects on Multi-Drug-Resistant human pathogens. Endophytic fungus TPL11 and TPL14 showed maximum inhibition in agar plug and agar well diffusion assay. The ethyl acetate crude extract effectively suppressed growth of MRSA (Methicillin-resistant Staphylococcus aureus) ATCC 43300,700699 strains and VRE (Vancomycin-resistant Enterococcus) with the Inhibition zone of 22 ± 0.05, 23 ± 0.11 and 24 ± 0.11 mm respectively with minimum inhibitory concentration (MIC) of 3.125 µg/mL. Whereas TPL11 fungus revealed antibiosis of 22 ± 0.05 and 21 ± 0.15 mm against MRSA(ATCC 43300,700699) and 24 ± 0.05 mm for VRE with MIC of 6.25,3.125 and 1.56 μg/mL respectively. The MIC (Minimum inhibitory concentration) index further confirmed that both the extracts were bacteriostatic against MRSA and bactericidal against VRE. The isolates TPL11 and TPL14 were identified as Fusarium oxysporum and Nigrospora sphaerica by 18S rRNA internal transcribed spacer (ITS) sequencing. To our insight, it is the first report to reveal the presence of F.oxysporum and N.sphaerica in T.pallida and their antibacterial activity.

Design, synthesis, and biological evaluation of novel pleuromutilin derivatives containing benzimidazoles as effective anti-MRSA agents.

A series of pleuromutilin derivatives containing benzimidazole were designed, synthesized, and evaluated for their antibacterial activities against Methicillin-resistant Staphylococcus aureus (MRSA) in this study. The in vitro antibacterial activities of the synthesized derivatives against four strains of S. aureus (MRSA ATCC 43300, S. aureus ATCC 29213, S. aureus 144, and S. aureus AD3) were determined by the broth dilution method. Among these derivatives, compound 58 exhibited superior in vitro antibacterial effect against MRSA (minimal inhibitory concentration [MIC] = 0.0625 μg/mL) than tiamulin (MIC = 0.5 μg/mL). Compound 58 possessed a faster bactericidal kinetic and a longer post-antibiotic effect time against MRSA than tiamulin. Meanwhile, at 8 μg/mL concentration, compound 58 did not display obviously cytotoxic effect on the RAW 264.7 cells. In addition, compound 58 (-2.04 log10 CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (-1.02 log10 CFU/mL) in reducing MRSA load in mice thigh infection model. In molecular docking study, compound 58 can successfully attach to the 50S ribosomal active site (the binding free energy is -8.11 kcal/mol). Therefore, compound 58 was a potential antibacterial candidate for combating MRSA infections.

Bioactive Metabolites of Lactiplantibacillus plantarum K014 Against Methicillin-Resistant Staphylococcus aureus ATCC43300 and In Vitro Evaluation of Its Antibacterial, Antioxidant and Anti-inflammatory Activities.

This study aims to evaluate the effects of bioactive metabolites produced by lactic acid bacteria against methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300. A total of six lactic acid bacteria (LAB) were selected to evaluate the antimicrobial activity against MRSA ATCC 43300, a skin pathogen that is highly resistant to most antibiotics. The K014 isolate from a fermented vegetable recorded the highest inhibition against MRSA ATCC 43300 at 91.93 ± 0.36%. 16S rRNA sequencing revealed the K014 isolate is closely related to L. plantarum and the sequence was subsequently deposited in the GenBank database with an accession number of MW180960, named as Lactiplantibacillus plantarum K014. The cell-free supernatant (CFS) of L. plantarum K014 had tolerance to high temperature as well as acidic pH. The bioactive metabolites, such as hydrogen peroxide, lactic acid and hyaluronic acid, were produced by L. plantarum K014. Result from ABTS assay showed higher antioxidant activity (46.28%) as compared to that obtained by DPPH assay (2.97%). The CFS had showed anti-inflammatory activity for lipoxygenase (LOX) assay at 43.66%. The bioactive metabolites of L. plantarum K014 showed very promising potential to be used topical skin pathogens.

Synthesis and Inhibitory Activity of Machaeridiol-Based Novel Anti-MRSA and Anti-VRE Compounds and Their Profiling for Cancer-Related Signaling Pathways.

Three unique 5,6-seco-hexahydrodibenzopyrans (seco-HHDBP) machaeridiols A–C, reported previously from Machaerium Pers., have displayed potent activities against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium, and E. faecalis (VRE). In order to enrich the pipeline of natural product-derived antimicrobial compounds, a series of novel machaeridiol-based analogs (1–17) were prepared by coupling stemofuran, pinosylvin, and resveratrol legends with monoterpene units R-(−)-α-phellandrene, (−)-p-mentha-2,8-diene-1-ol, and geraniol, and their inhibitory activities were profiled against MRSA ATCC 1708, VRE ATCC 700221, and cancer signaling pathways. Compounds 5 and 11 showed strong in vitro activities with MIC values of 2.5 μg/mL and 1.25 μg/mL against MRSA, respectively, and 2.50 μg/mL against VRE, while geranyl analog 14 was found to be moderately active (MIC 5 μg/mL). The reduction of the double bonds of the monoterpene unit of compound 5 resulted in 17, which had the same antibacterial potency (MIC 1.25 μg/mL and 2.50 μg/mL) as its parent, 5. Furthermore, a combination study between seco-HHDBP 17 and HHDBP machaeriol C displayed a synergistic effect with a fractional inhibitory concentrations (FIC) value of 0.5 against MRSA, showing a four-fold decrease in the MIC values of both 17 and machaeriol C, while no such effect was observed between vancomycin and 17. Compounds 11 and 17 were further tested in vivo against nosocomial MRSA at a single intranasal dose of 30 mg/kg in a murine model, and both compounds were not efficacious under these conditions. Finally, compounds 1–17 were profiled against a panel of luciferase genes that assessed the activity of complex cancer-related signaling pathways (i.e., transcription factors) using T98G glioblastoma multiforme cells. Among the compounds tested, the geranyl-substituted analog 14 exhibited strong inhibition against several signaling pathways, notably Smad, Myc, and Notch, with IC50 values of 2.17 μM, 1.86 μM, and 2.15 μM, respectively. In contrast, the anti-MRSA actives 5 and 17 were found to be inactive (IC50 > 20 μM) across the panel of these cancer-signaling pathways.

Design, synthesis and biological evaluation of novel pleuromutilin derivatives possessing 4-aminothiophenol linker as promising antibacterial agents

A series of novel pleuromutilin derivatives containing 4-aminothiophenol moieties have been designed and synthesized as promising antibacterial agents against Methicillin-resistant Staphylococcus aureus (MRSA). The in vitro antibacterial activity of these semisynthetic derivatives against 4 strains of S. aureus (MRSA ATCC 43300, S. aureus ATCC 29213, S. aureus 144 and S. aureus AD3) was evaluated by the broth dilution method. Most of the synthesized derivatives displayed prominent in vitro activity (MIC ≤ 0.5 µg/mL). 12 Compounds possessed superior antibacterial activity against MRSA compared with valnemulin and retapamulin (MIC = 0.0625 µg/mL). Compounds 12, 16a, 16c and 19 exhibited the most effective antibacterial effect against MRSA (MIC = 0.015 µg/mL). Furthermore, the time-kill curves showed compounds 12 and 19 had a certain inhibitory effect against MRSA in vitro. Compounds 12 and 19 possessed longer PAE time (2.74 h and 3.11 h, respectively) than tiamulin (PAE = 2.04 h) against MRSA after exposure at 4 × MIC concentration for 2 h. Compounds 12 and 19 also displayed superior in vivo antibacterial efficacy (-1.20 log10 CFU/mL and −1.21 log10 CFU/mL, respectively) than tiamulin (-0.75 log10 CFU/mL) in reducing MRSA load in the mice thigh infection model. In addition, compound 19 had barely inhibitory effect on RAW 264.7 and 16HBE cells at 8 µg/mL. In molecular docking study, upon docking into the 50S ribosomal subunit, the binding free energy (ΔGb) of compound 12 and 19 was calculated to be −9.02 kcal/mol and −9.89 kcal/mol, respectively.

Plate-associated localized osteitis in mini-pig by biofilm-forming Methicillin-resistant Staphylococcusaureus (MRSA): establishment of a novel experimental model

PurposeThe increasing number of implant-associated infections during trauma and orthopedic surgery caused by biofilm-forming Staphylococcus aureus in combination with an increasing resistance of conventional antibiotics requires new therapeutic strategies. One possibility could be testing for different therapeutic strategies with differently coated plates. Therefore, a clinically realistic model is required. The pig offers the best comparability to the human situation, thus it was chosen for this model. The present study characterizes a novel model of a standardized low-grade acute osteitis with bone defect in the femur in mini-pigs, which is stabilized by a titanium locking plate to enable further studies with various coatings.MethodsA bone defect was performed on the femur of 7 Aachen mini-pigs and infected with Methicillin-resistant S. aureus (MRSA ATCC 33592). The defect zone was stabilized with a titanium plate. After 14 days, a plate change, wound debridement and lavage were performed. Finally, after 42 days, the animals were lavaged and debrided again, followed by euthanasia. The fracture healing was evaluated radiologically and histologically.ResultsA local osteitis with radiologically visible lysis of the bone could be established. The unchanged high Colony-forming Units (CFU) in lavage, the significant differences in Interleukin (IL)-6 in blood compared to lavage and the lack of increase in Alkaline Phosphates (ALP) in serum over the entire observation period show the constant local infection.ConclusionThe study shows the successful induction of local osteitis with lysis of the bone and the lack of enzymatic activity to mineralize the bone. Therefore, this standardized mini-pig model can be used in further clinical studies, to investigate various coated implants, bone healing, biofilm formation and immune response in implant-associated osteitis.

Antimicrobial photodynamic therapy (aPDT) with curcumin controls intradermal infection by Staphylococcus aureus in mice with type 1 diabetes mellitus: a pilot study.

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the main pathogens that cause infections in diabetic individuals. In this paper, we report the outcomes of our investigation on the intradermal application of antimicrobial photodynamic therapy (PDT) with curcumin in an infection induced by MRSA ATCC 43300 strain in the ear of mice with Type 1 Diabetes Mellitus (T1DM). A solution containing 100μg of curcumin was photoactivated ex vivo with a LED light (450nm) delivering a fluency of 13.5J/cm3. This solution was administered in the ear intradermally, at the same inoculum site as the MRSA ATCC 43300 strain (PDT Group). This study also included the use of two control groups (both infected): One was treated with saline and the other was treated with non-photoactivated curcumin. The animals were euthanized 24h after these treatments and samples of draining lymph node and treated ear were collected for examination. The PDT group showed lower bacterial load in the draining lymph node when compared to the saline and curcumin groups (p-value <0.05) 24h after treatment. In addition to bacterial load, the PDT group presented a higher concentration of nitrates and nitrites in the draining lymph node when compared to the saline and curcumin groups (p-value <0.001). Examining the infectious site, despite apparently having similar inflammatory cell recruitment compared with the control groups, the PDT group showed a profile with less intense activity in the myeloperoxidase expression when compared to the saline group (p-value <0.001). Additionally, the detected concentration of cytokines such as IL-1β, IL-12, and IL-10 was significantly lower in the PDT group when compared to the saline group (p-value <0.01; p-value <0.05; p-value <0.05, respectively), thus presenting a less intense inflammatory response during infection resolution. Our pilot study showed for the first time the therapeutic potential of PDT using curcumin when administered intradermally in the treatment of infections caused by S. aureus in mice with T1DM.

Schottiin, a new prenylated isoflavones from Psorothamnus schottii and antibacterial synergism studies between methicillin and fremontone against methicillin-resistant Staphylococcus aureus ATCC 1708

Bioactivity guided isolation of an ethanol extract of the root of Psoromanthus schottii (Family Fabaceae) afforded a new prenylated isoflavone, named schottiin (5,7,5’-trihydroxy-4’-O-methyl-6’-(3,3-dimethylallyl)-isoflavone) (1), together with four other isoflavones, including fremontone (2), 5,7,4’,5’-tetrahydroxy-2’-(3,3-dimethylallyl)-isoflavone (3), glycyrrhisoflavone (4) and fremontin (5), of which 3 and 4 identified as isomeric mixture. Structures of 1-5 were determined by full spectroscopic analyses. A comprehensive 2 D NMR spectral data has allowed revising the structure of fremontone as 2 from previously reported 2 A. Compound 2 showed weak in-vitro antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). A combination study using a checkerboard assay between fremontone (2) and methicillin exhibited a synergistic activity with 8-fold decrease in MIC of methicillin, as well as an additive effect with vancomycin against MRSA ATCC 1708. Compounds 1 and 2 also showed moderate antiplasmodial activity against chloroquine-sensitive (D6) and -resistant (W2) strains of Plasmodium falciparum with no cytotoxicity to mammalian Vero cells.

A click chemistry approach to pleuromutilin derivatives, evaluation of anti-MRSA activity and elucidation of binding mode by surface plasmon resonance and molecular docking

Novel series of pleuromutilin analogs containing substituted 1,2,3-triazole moieties were designed, synthesised and assessed for their in vitro antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA). Initially, the in vitro antibacterial activities of these derivatives against 4 strains of S. aureus (MRSA ATCC 43300, ATCC 29213, AD3, and 144) were tested by the broth dilution method. Most of the synthesised pleuromutilin analogs displayed potent activities. Among them, compounds 50, 62, and 64 (MIC = 0.5∼1 µg/mL) showed the most effective antibacterial activity and their anti-MRSA activity were further studied by the time-killing kinetics approach. Binding mode investigations by surface plasmon resonance (SPR) with 50S ribosome revealed that the selected compounds all showed obvious affinity for 50S ribosome (KD = 2.32 × 10−8∼5.10 × 10−5 M). Subsequently, the binding of compounds 50 and 64 to the 50S ribosome was further investigated by molecular modelling. Compound 50 had a superior docking mode with 50S ribosome, and the binding free energy of compound 50 was calculated to be −12.0 kcal/mol.

Synthesis and anti-methicillin-resistant Staphylococcus aureus activity of 5,7-dibromo-2-benzoylbenzofurans alone and in combination with antibiotics

A series of 5,7-dibromo-2-benzoylbenzofurans were synthesized by the Rap–Stoermer condensation of 5,7-dibromosalicylaldehyde with diverse phenacyl bromides and evaluated for in-vitro antibacterial activities against methicillin-sensitive Staphylococcus aureus (MSSA) ATCC 29213, methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, and MRSA ATCC 33591 by agar dilution method. The synergistic effects were determined by using the agar dilution checkerboard assay. The derivatives bearing carboxylic acid functional groups exhibited reasonable activity against MRSA strains with the best MIC = 32 µg/mL (9b, 9d). Moreover, the additive or synergistic interactions against MRSA strains was observed in six combinations (1b + cefuroxime/gentamicin, 1c + ciprofloxacin/gentamicin, 9b + gentamicin, and 9c + ciprofloxacin) with the fractional inhibitory concentration index (FICI) values in the range of 0.375–1.0. Significantly, the MICs of these antibiotics were reduced 2–4-fold. The results of the MTT assay illustrated the low mammalian cell cytotoxicity of these potent compounds.

Synthesis of 1ʹ-acetoxychavicol acetate (ACA) analogues and their inhibitory activities against methicillin-resistant Staphylococcus aureus

A series of 1ʹ-acetoxychavicol acetate analogues were synthesised and evaluated for their antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA) using broth microdilution technique. The minimum inhibitory concentration (MIC) was used to determine whether the compounds had potential as inhibitory agents against the MRSA ATCC 43300, and the compounds with antimicrobial potential (&lt;2000 μg ml–1) were tested for minimum bactericidal concentration (MBC). Based on this assay, compound 1 exhibited potent antimicrobial activity with MIC value of 250 μg ml–1. Meanwhile, compounds 2 and 13 showed the moderate activity with MIC values of 500 μg ml–1, respectively.

Anti-Methicillin-Resistant Staphylococcus aureus (MRSA) of Ethanol Extract of God's Crown (Phaleria macrocarpa) Leaves, Peel, and Fruit Flesh

Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogen that becomes the main concern since it is a multidrug-resistant organism and causes high morbidity and mortality. This study aimed to investigate the antibacterial activity of ethanolic extract of Phaleria macrocarpa leaves, peel, and fruit flesh on MRSA. This study was an experimental laboratory study with a post-test only control group design to assess the antibacterial activity of ethanolic extract from leaves, peel, and fruit flesh of Phaleria macrocarpa against MRSA ATCC 43300 and MRSA clinical isolates using a disk diffusion method. Extracts from the leaves, peel, and flesh of Phaleria macrocarpa had potential as an antibacterial agent against MRSA ATCC 43300 at a concentration of 40%, although not yet equivalent to antibiotic control. The ethanol extract of Phaleria macrocarpa peel at a concentration of 30-40% had potential as an antibacterial agent against MRSA clinical isolates, although not yet equivalent to antibiotic control. Further research needs to be performed so that Phaleria macrocarpa extract can be a potential source of subsequent antibacterial development against MRSA.

Comparison of Antibacterial Activity of Sambiloto (Andrographis paniculata) Ethanol and Water Stem Extract Against Methicillin-Resistant Staphylococcus aureus (MRSA) ATCC 3351 In Vitro

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is penicillin and cephalosporine resistant Staphylococcus aureus which is a major cause of nosocomial infection. Various studies have been conducted for resistant cases, especially herbs which have antibacterial activity. Sambiloto (Andrographis paniculata) is an example of herb which has antibacterial activity due to the presence of andrographolide. Andrographolide soluble in ethanol and poorly in water, while extraction with alcohol causes andrographolide’s degradation. This study aimed to investigate the antimicrobial activity of ethanol and water stem extract and compare them against MRSA ATCC 3351 in vitro.Methods: This is an experimental study with a post-test only control group design and conducted by disc diffusion technique to obtain an inhibition zone against MRSA.Result: The result of this study showed the mean inhibitory zone of ethanol stem extract was 5,87mm, 6,77mm, 7,87mm respectively for 25%, 50%, and 100% concentrations, while 1% concentration did not show antibacterial activity. Water stem extract at 1%, 25%, 50%, and 100% concentrations showed mean inhibitory zone was at 4,57mm, 7,17mm, 8,67mm, and 9,67mm respectively.Conclusion: Ethanol and water stem extract showed antibacterial activity against MRSA. The independent sample t-test didn’t show a difference between ethanol and water stem extract of Andrographis paniculata toward MRSA (p&gt;0,05).

Synergistic Potential of Antimicrobial Combinations Against Methicillin-Resistant Staphylococcus aureus.

The chemotherapeutic options for methicillin-resistant Staphylococcus aureus (MRSA) infections are limited. Due to the multiple resistant MRSA, therapeutic failure has occurred frequently, even using antibiotics belonging to different categories in clinical scenarios, very recently. This study aimed to investigate the interactions between 11 antibiotics representing different mechanisms of action against MRSA strains and provide therapeutic strategies for clinical infections. Susceptibilities for MRSA strains were determined by broth microdilution or agar dilution according to CLSI guideline. By grouping with each other, a total of 55 combinations were evaluated. The potential synergism was detected through drug interaction assays and further investigated for time-killing curves and an in vivo neutropenic mouse infection model. A total of six combinations (vancomycin with rifampicin, vancomycin with oxacillin, levofloxacin with oxacillin, gentamycin with oxacillin, clindamycin with oxacillin, and clindamycin with levofloxacin) showed synergistic activity against the MRSA ATCC 43300 strain. However, antibacterial activity against clinical isolate #161402 was only observed when vancomycin combined with oxacillin or rifampicin in time-killing assays. Next, therapeutic effectiveness of vancomycin/oxacillin and vancomycin/rifampicin was verified by an in vivo mouse infection model inoculated with #161402. Further investigations on antimicrobial synergism of vancomycin plus oxacillin and vancomycin plus rifampicin against 113 wild-type MRSA strains were evidenced by combined antibiotic MICs and bacterial growth inhibition and in vitro dynamic killing profiles. In summary, vancomycin/rifampicin and vancomycin/oxacillin are the most potential combinations for clinical MRSA infection upon both in vitro and in vivo tests. Other synergetic combinations of levofloxacin/oxacillin, gentamycin/oxacillin, clindamycin/oxacillin, and clindamycin/fosfomycin are also selected but may need more assessment for further application.

Screening of Indonesian peat soil bacteria producing antimicrobial compounds.

The development and world-wide spread of multidrug-resistant (MDR) bacteria have a high concern in the medicine, especially the extended-spectrum of beta-lactamase (ESBL) producing Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA). There are currently very limited effective antibiotics to treat infections caused by MDR bacteria. Peat-soil is a unique environment in which bacteria have to compete each other to survive, for instance, by producing antimicrobial substances. This study aimed to isolate bacteria from peat soils from South Kalimantan Indonesia, which capable of inhibiting the growth of Gram-positive and Gram-negative bacteria. Isolates from peat soil were grown and identified phenotypically. The cell-free supernatant was obtained from broth culture by centrifugation and was tested by agar well-diffusion technique against non ESBL-producing E. coli ATCC 25922, ESBL-producing E. coli ATCC 35218, methicillin susceptible Staphylococcus aureus (MSSA) ATCC 29,213 and MRSA ATCC 43300. Putative antimicrobial compounds were separated using SDS-PAGE electrophoresis and purified using electroelution method. Antimicrobial properties of the purified compounds were confirmed by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In total 28 isolated colonies were recovered; three (25PS, 26PS, and 27PS) isolates produced proteins with strong antimicrobial activities against both reference strains. The substance of proteins from three isolates exerted strong antimicrobial activity against ESBL-producing E. coli ATCC 35,218 (MIC = 2,80 µg/mL (25PS), 3,76 µg/mL (26PS), and 2,41 µg/mL (27PS), and MRSA ATCC 43,300 (MIC = 4,20 µg/mL (25PS), 5,65 µg/mL (26PS), and 3,62 µg/mL (27PS), and also had the ability bactericidal properties against the reference strains. There were isolates from Indonesian peat which were potentials sources of new antimicrobials.

Graphene Decorated Zinc Oxide and Curcumin to Disinfect the Methicillin-Resistant Staphylococcus aureus.

Sometimes, life-threatening infections are initiated by the biofilm formation facilitated at the infection site by the drug-resistant bacteria Staphylococcus aureus. The aggregation of the same type of bacteria leads to biofilm formation on the delicate tissue, dental plaque, and skin. In the present investigation, a Graphene (Gr)-based nano-formulation containing Curcumin (C.C.M.) and Zinc oxide nanoparticles (ZnO-NPs) showed a wide range of anti-microbial activity against Methicillin-resistant Staphylococcus aureus (MRSA) biofilm and demonstrated the anti-microbial mechanism of action. The anti-microbial effect of GrZnO nanocomposites, i.e., GrZnO-NCs, suggests that the integrated graphene-based nanocomposites effectively suppressed both sensitive as well as MRSA ATCC 43300 and BAA-1708 isolates. The S. aureus inhibitory effect of GrZnO-NCs improved >5-fold when combined with C.C.M., and demonstrated a M.I.C. of 31.25 µg/mL contrasting with the GrZnO-NCs or C.C.M. alone having M.I.C. value of 125 µg/mL each. The combination treatment of GrZnO-NCs or C.C.M. inhibited the M.R.S.A. topical dermatitis infection in a mice model with a significant decrease in the CFU count to ~64%. Interestingly, the combination of C.C.M. and GrZnO-NCs damaged the bacterial cell wall structure, resulting in cytoplasm spillage, thereby diminishing their metabolism. Thus, owing to the ease of synthesis and highly efficient anti-microbial properties, the present graphene-based curcumin nano-formulations can cater to a new treatment methodology against M.R.S.A.