Multidrug-resistant Staphylococcus Aureus Research Articles

Biomimetic Bacteriophage-Like Particles Formed from Probiotic Extracts and NO Donors for Eradicating Multidrug-Resistant Staphylococcus aureus.

Effectively clearing multidrug-resistant bacteria through nonantibiotic treatments is crucial for the recovery of infected tissues in favorable biological environments. Herein, a thermally responsive donor of cell-messenger nitric oxide (NO) is combined with extracts of food-grade Lactobacillus casei to form biomimetic phage-like microparticles with a tailspike structure. These particles can invade bacterial membranes and release NO to disrupt nitrogen and respiratory metabolisms, which initiates the programmed death of multidrug-resistant Staphylococcus aureus (MRSA) for inducing lysis, like the bacterial virus. Experiments suggest that these microparticles can also weaken bacterial toxicity and provide favorable conditions for cell proliferation because of the continuously released NO. By encapsulating these microparticles into graphene-oxide-doped polymers, a dual-mode antibacterial hydrogel (DMAH) can be constructed. In vivo results reveal that the DMAH achieves a long-time sterilization of MRSA with 99.84 ± 0.13% antibacterial rate in the dark because of the phage-like performance of the biomimetic microparticles. In its other antibacterial mode, DMAH subjected to 20min of near-infrared irradiation release NO, which, together with the photothermal effect, synergistically damages bacterial cell membranes to achieve very fast disinfection (97.13 ± 0.41% bactericidal rate). This multifunctional hydrogel can also significantly accelerate wound healing due to the phage-like particles.

Biogenic synthesis of CuO-NPs as nanotherapeutics approaches to overcome multidrug-resistant Staphylococcus aureus (MDRSA)

Due to the misuse of antibiotics, the multidrug-resistant Staphylococcus aureus (MDRSA) has caused serious infections and become more difficult to deal with. Here we propose to synthesise copper oxide nanoparticles (CuO-NPs) using a cell-free filter of Streptomyces rochei to enhance antibiotics activity against (MDRSA) and kill them. Characterisation of CuO-NPs using ultraviolet, dynamic light scattering, zeta potential, transmission electron microscopic (TEM), and X-ray diffraction, were investigated. The antibacterial action of the CuO-NPs was tested against standard strain and clinical isolates using the agar well diffusion method and the microdilution assay. The results showed the monodispersed spherical shape CuO-NPs with a mean diameter of 10.7 nm and were found to be active against (MDRSA). By a combination of CuO-NPs with different antibiotics, the highest synergistic effect was observed with cefoxitin, the minimum inhibitory concentration (MIC) was reduced to 6.5 for CuO-NPs, and 19.5 for cefoxitin. Time-kill assay showed the highest reduction in log10 colony-forming unit (CFU)/ml of initial inoculum of MRSA after 24 h. The HFB-4 cells cultured in the presence of CuO-NPs showed normal morphology with 100% viability at 8 µg/ml. TEM showed that combination (1/4 MIC cefoxitin +1/16 MIC CuO-NPs) highly damages bacterial cells’ shape. The biosynthesis CuO-NPs showed antibacterial activity against S. aureus suggesting a promising alternative in clinical.

Injectable Carrier-Free Hydrogel Dressing with Anti-Multidrug-Resistant Staphylococcus aureus and Anti-Inflammatory Capabilities for Accelerated Wound Healing.

Antibacterial hydrogels have gradually become a powerful weapon to treat bacterially infected wounds and accelerate healing. In this paper, we designed a small-molecule self-healing antibacterial hydrogel containing 100% drug-loaded benzyl 3β-amino-11-oxo-olean-12-en-30-oate (GN-Bn), which was governed by π-π stacking, hydrogen bonding, and van der Waals forces. Due to the carrier-free design concept, the problems of interbatch variability during sample preparation and carrier-related toxicity can be effectively avoided. Moreover, the GN-Bn hydrogel exhibited promising antibacterial activities against multidrug-resistant Staphylococcus aureus (MRSA). The minimum inhibitory concentration (MIC) of the GN-Bn hydrogel was 1.5625 nmol/mL, which was lower than those against clinical agents such as norfloxacin, penicillin, and tetracycline. This is attributed to its unique antibacterial mechanism that aims at killing bacteria or preventing their growth by regulating arginine biosynthesis and metabolism through both transcriptomic (RNA-seq) analysis and quantitative polymerase chain reaction (qPCR) analysis. In addition, the GN-Bn hydrogel can also inhibit proinflammatory cytokines (TNF-α, IL-1β, and IL-6) to promote wound healing. Collectively, the GN-Bn hydrogel elicited dual therapeutic effects on an MRSA-infected full-thickness skin wound model through its antibacterial and anti-inflammatory activities, which is attributed to the fact that the GN-Bn hydrogel has multiple advantages including sufficient mechanical stability, biocompatibility, and unique antibacterial mechanisms, making it significantly accelerate MRSA-infected full-thickness skin wound healing as a wound dressing. In a word, the GN-Bn antibacterial hydrogel dressing with an anti-inflammatory and antibacterial bifunctional material holds great potential in clinical application.

Enhancement of wound healing via topical application of natural products: In vitro and in vivo evaluations

Intact skin is the first physical barrier against all microbial infections. Thus, in the cases of wounds, burns, and skin damage, bacteria can infect and invade the deeper layers of skin to the bloodstream and other organs leading to severe illnesses. Thus, our study aims to investigate the potential activity of natural products, propolis and honeybee venom, to control wound infections with multi-drug resistant Staphylococcus aureus (MDRSA) and safely accelerate the wound healing. First, this study characterized the clinically isolated S. aureus using biochemical, molecular, and antibiotic sensitivity tests. Then, the hydrogel was prepared via mixing chitosan with honey, propolis, and venom at different ratios, followed by physicochemical characterization and biological examination. The in vivo experiment results after topical application of optimum concentrations revealed that both venom and propolis have significant antibacterial activity at different temperatures. The IC50 of both propolis antioxidant and cytotoxicity assays was found to be 40.07 ± 2.18 μg/mL and 18.3 μg/mL, respectively. The cocktail bacteria showed both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 10 µg/mL and of 300 µg/mL with venom respectively & MIC and MBC of 100 µg/mL, 300 µg/mL with propolis respectively. The use of hydrogel was effective against wound infection and enhanced wound healing during 14 days. Before starting clinical trials, further studies can be done on large animal models.

Antimicrobial activity of supernatants produced by bacteria isolated from Brazilian stingless bee’s larval food

BackgroundThe discovery of new molecules with antimicrobial properties has been a promising approach, mainly when related to substances produced by bacteria. The use of substances produced by bees has evidenced the antimicrobial action in different types of organisms. Thus, the use of bacteria isolated from larval food of stingless bees opens the way for the identification of the new molecules. The effect of supernatants produced by these bacteria was evaluated for their ability to inhibit the growth of bacteria of clinical interest. Furthermore, their effects were evaluated when used in synergy with antibiotics available in the pharmaceutical industry.ResultsA few supernatants showed an inhibitory effect against susceptible and multiresistant strains in the PIC assay and the modulation assay. Emphasizing the inhibitory effect on multidrug-resistant strains, 7 showed an effect on multidrug-resistant Escherichia coli (APEC), Klebsiella pneumoniae carbapenemase (KPC), multidrug-resistant Pseudomonas aeruginosa, and multidrug-resistant Staphylococcus aureus (MRSA) in the PIC assay. Of the supernatants analyzed, some presented synergism for more than one species of multidrug-resistant bacteria. Nine had a synergistic effect with ampicillin on E. coli (APEC) or S. aureus (MRSA), 5 with penicillin G on E. coli (APEC) or KPC, and 3 with vancomycin on KPC.ConclusionIn summary, the results indicate that supernatants produced from microorganisms can synthesize different classes of molecules with potent antibiotic activity against multiresistant bacteria. Thus, suggesting the use of these microorganisms for use clinical tests to isolate the molecules produced and their potential for use.

Lactococcus lactis secreting phage lysins as a potential antimicrobial against multi-drug resistant Staphylococcus aureus.

BackgroundStaphylococcus aureus is an opportunistic Gram-positive bacterium that can form biofilm and become resistant to many types of antibiotics. The treatment of multi-drug resistant Staphylococcus aureus (MDRSA) infection is difficult since it possesses multiple antibiotic-resistant mechanisms. Endolysin and virion-associated peptidoglycan hydrolases (VAPGH) enzymes from bacteriophage have been identified as potential alternative antimicrobial agents. This study aimed to assess the ability of Lactococcus lactis NZ9000 secreting endolysin and VAPGH from S. aureus bacteriophage 88 to inhibit the growth of S. aureus PS 88, a MDRSA.MethodEndolysin and VAPGH genes were cloned and expressed in L. lactis NZ9000 after fusion with the SPK1 signal peptide for secretion. The recombinant proteins were expressed and purified, then analyzed for antimicrobial activity using plate assay and turbidity reduction assay. In addition, the spent media of the recombinant lactococcal culture was analyzed for its ability to inhibit the growth of the S. aureus PS 88.ResultsExtracellular recombinant endolysin (Endo88) and VAPGH (VAH88) was successfully expressed and secreted from L. lactis which was able to inhibit S. aureus PS 88, as shown by halozone formation on plate assays as well as inhibition of growth in the turbidity reduction assay. Moreover, it was observed that the spent media from L. lactis NZ9000 expressing Endo88 and VAH88 reduced the viability of PS 88 by up to 3.5-log reduction with Endo88 being more efficacious than VAH88. In addition, Endo88 was able to lyse all MRSA strains tested and Staphylococcus epidermidis but not the other bacteria while VAH88 could only lyse S. aureus PS 88.ConclusionRecombinant L. lactisNZ9000 expressing phage 88 endolysin may be potentially developed into a new antimicrobial agent for the treatment of MDRSA infection.

Multidrug resistant Staphylococcus aureus; its incidence and antibiotic sensitivity pattern.

Objective: To determine incidence of MRSA in our community and its antibiotic susceptibility pattern. Study Design: Cross Sectional study. Setting: Department of Pathology, Sahara Medical College Narowal. Period: January 2020 to June 2020. Material & Methods: Bacterial isolates were taken from the samples of blood, pus and other body fluids sent to the hospital laboratory to determine culture and sensitivity pattern. Those samples positive for staphylococcus aureus were included in the study for further examination. MRSA were detected using conventional technique (catalase, coagulase and DNase methods) and confirmed by phenotypic and molecular characterization techniques (cefoxitin and oxacillin sensitivity, mec-A gene and 16S rRNA genes sequencing methods). Their antibiotic sensitivity was determined using standard Kirby Bauer disc diffusion technique. Chi square test was applied on collected data using SPSS-24. Results: Total 158 bacterial isolates containing staphylococcus aureus were included in the study. MRSA (multi drug resistant staphylococcus aureus) was detected in 33.5% samples and MSSA (multi drug sensitive staphylococcus aureus) was detected in 66.5% samples. Frequency of MSSA was more than MRSA. Male gender was more affected (60%) than female (40%). All bacterial isolates containing staphylococcus aureus were resistant to oxacillin and cefoxitin. MRSA isolates were sensitive to vancomycin, linezolid, teicoplanin, fosfomycin and fusidic acid, rifampicin, clindamycin, minocyclin and chloramphenicol, while resistant to penicillin, azithromycin, ciprofloxacin, erythromycin and co-trimoxazole. Conclusion: MRSA is detected by conventional technique followed by phenotypic and molecular characterization methods for confirmation. Methicillin sensitive staphylococcus aureus was detected more commonly than methicillin resistant staphylococcus aureus in our study sample. Proper culture and antibiotic sensitivity pattern is necessary to deal with MRSA.

Antimicrobial Profile of Actinomycin D Analogs Secreted by Egyptian Desert Streptomyces sp. DH7.

Egyptian deserts are an underexplored ecological niche, especially the Sinai Peninsula. In our recent study, we explored this extreme environment and shed light on the bioactive capabilities of desert Actinobacteria isolated from Sinai. Fifty desert Actinobacteria were isolated from the Sinai desert using mineral salt media, basal media, and starch casein media. The filtrate of Streptomyces sp. DH 7 displayed a high inhibitory effect against multidrug-resistant Staphylococcus aureus (MRSA) strains. The 16S rDNA sequencing confirmed that isolate DH7 belongs to the genus Streptomyces. The NJ phylogenetic tree showed relatedness to the Streptomyces flavofuscus strain NRRL B-2594 and Streptomyces pratensis strain ch24. The minimum inhibitory concentrations against MRSA were 16 and 32 μg/μL. Chemical investigation of the ethyl acetate extract of Streptomyces sp. DH7 led to the isolation and purification of natural products 1–4. Structure elucidation of the purified compounds was performed using detailed spectroscopic analysis including 1 and 2D NMR, and ESI-MS spectrometry. To the best of our knowledge, this is the first report for the isolation of compounds 1–4 from a natural source, while synthetic analogs were previously reported in the literature. Compounds 3–4 were identified as actinomycin D analogues and this is the first report for the production of actinomycin D analogs from the Sinai desert with an inhibitory effect against MRSA. We indorse further study for this analog that can develop enhanced antimicrobial activities. We confirm that the desert ecosystems in Egypt are rich sources of antibiotic-producing Actinobacteria.

Accelerated antibacterial red-carbon dots with photodynamic therapy against multidrug-resistant Acinetobacter baumannii.

The emergence of antibiotic resistance in bacteria is a major public-health issue. Synthesis of efficient antibiotic-free material is very important for fighting bacterial infection-related diseases. Herein, red-carbon dots (R-CDs) with a broad range of spectral absorption (350–700 nm) from organic bactericides or intermediates were synthesized through a solvothermal route. The prepared R-CDs not only had intrinsic antibacterial activities, but also could kill multidrug-resistant bacteria (multidrug-resistant Acinetobacter baumannii (MRAB) and multidrug-resistant Staphylococcus aureus (MRSA)) effectively by generating reactive oxygen species. Furthermore, R-CDs could eliminate and inhibit the formation of MRAB biofilms, while conferring few side effects on normal cells. A unique property of R-CDs was demonstrated upon in vivo treatment of antibiotic-sensitive MRAB-induced infected wounds. These data suggested that this novel R-CDs-based strategy might enable the design of next-generation agents to fight drug-resistant bacteria.Electronic Supplementary MaterialSupplementary material is available for this article at 10.1007/s40843-021-1770-0 and is accessible for authorized users.

Virulence and Drug-Resistance of Staphylococcus aureus Strains Isolated from Venous Ulcers in Polish Patients

Infected chronic venous ulcers (VUs) represent a major health problem. We analysed the aerobic microbiome in the VUs, the virulence, and drug-resistance of Staphylococcus aureus (SA) strains. Swabs from 143 outpatients and inpatients Polish subjects were collected. SA strains were tested for drug sensitivity using a phenotyping method and for methicillin-resistant SA (MRSA) and macrolide-lincosamide-streptogramin B (MLSB) resistance using PCR. We analysed virulence genes, the genetic similarity of strains, and performed Staphylococcal cassette chromosome mec typing and Staphylococcal protein A typing. SA was isolated as a single one in 34.9% of cases, 31.5% paired with another pathogen, and 33.6% S. aureus combined with at least two other strains. The majority of SA isolates (68.5%) possessed the virulence lukE gene. Drug resistance was significantly common in hospitalised than in ambulatory patients (OR 3.8; 95%CI 1.8–7.91). MLSB (altogether in 19.6% isolates) were observed mostly in non-hospitalised patients (OR 9.1; 95%CI 1.17–71.02), while MRSA was detected in 11.9% of strains equally. Hospitalisation and patient’s age group (aged > 78.0 or < 54.5 years) were significant predictors of the multi-drug resistant SA (MDR-SA). Over 30% of the infected VUs were associated with multi-species biofilms and presence of potentially highly pathogenic microorganisms. Elderly hospitalised patients with chronic venous ulcers are prone to be infected with a MDR-SA.

Unravelling the beehive air volatiles profile as analysed via solid-phase microextraction (SPME) and chemometrics

ObjectiveBeehive air therapy is recognized as a potential remedy for treating asthma, bronchitis, lung fibrosis, and respiratory tract infections. Developed countries in which beehive air therapy is currently authorized include Germany, Hungary, Slovenia, and Austria. However, scientific proof of its efficacy is lacking which warrants further chemical and biological analyses as a proof of concept. In this study, beehive air volatile profile was determined for the first time along with its individual components (bees, venom, honey, and beeswax). MethodsVolatile compounds were collected from beehive air using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC–MS). Antimicrobial assay of the air released from 4 beehive products was further performed against Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and multi drug-resistant Staphylococcus aureus (MRSA) using the in vitro agar-well diffusion and microtiter plate assays.Results and conclusions: A total of 56 volatile compounds were identified from beehive air, venom, bee insect and wax air including 6 fatty acids, 6 alcohols, 10 aldehydes, 5 esters, 1 ether, 9 hydrocarbons, 1 phenol, 7 ketones, 1 nitrogenous compound and 10 terpenes. The most abundant constituents were short-chain fatty acids (26.32%) while the lowest were the nitrogenous compounds (0.82%). The principal component analysis (PCA) scores plot of the UPLC/MS dataset showed the similarity of the beehive air to the insect bee's aroma profile. With regards to antimicrobial assay, beehive air and venom exerted the strongest antimicrobial activity among the examined bee products against S. aureus, K. pneumoniae, A. baumannii, and MRSA in agar-well diffusion assay but failing to exert an effect using microtiter plate assay as in case of bee venom against the aforementioned bacteria.

Design and High Expression of Non-glycosylated Lysostaphins in Pichia pastoris and Their Pharmacodynamic Study.

Lysostaphin is an effective antimicrobial agent to Staphylococcus, especially for the methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Staphylococcus aureus (MDRSA). In this study, the seven lysostaphin derived mutants (rLys) were designed to overcome the barrier of glycosylation during expression in Pichia pastoris. Among them, 127A and 127A232Q had highest antimicrobial activity (MIC values 0.07–0.3 μM) to S. aureus than others and the commercial lysostaphins (1–15.8 times). There was no glycosylation during the expression in 5-L fermenter level, with the high yield of 1315 mg/L (127A) and 1141 mg/L (127A232Q), respectively. Meanwhile, 127A and 127A232Q effectively killed 99.9% of S. aureus at low concentration (1 × MIC) within 30 min, without the regrowth of pathogen. They also showed low toxicity, high pH and temperature stability. The results of in vivo therapeutic effect of 127A and 127A232Q against high virulent S. aureus CVCC546 showed that 127A and 127A232Q increased the survival rate of infected mice up to 100% at the dose of 10 mg/kg than the untreated group, reduced the bacterial translocation by 5-7 log CFU (over 99%) in organs compared to the untreated group and alleviated multiple-organ injuries (liver, kidney and spleen). These data indicated that the non-glycosylated lysostaphin 127A and 127A232Q may be a promising therapeutic agent against MDR staphylococcal infections.

Deimmunized Lysostaphin Synergizes with Small-Molecule Chemotherapies and Resensitizes Methicillin-Resistant Staphylococcus aureus to β-Lactam Antibiotics.

There is an urgent need for novel agents to treat drug-resistant bacterial infections, such as multidrug-resistant Staphylococcus aureus (MRSA). Desirable properties for new antibiotics include high potency, narrow species selectivity, low propensity to elicit new resistance phenotypes, and synergy with standard-of-care (SOC) chemotherapies. Here, we describe analysis of the antibacterial potential exhibited by F12, an innovative anti-MRSA lysin that has been genetically engineered to evade detrimental antidrug immune responses in human patients. F12 possesses high potency and rapid onset of action, it has narrow selectivity against pathogenic staphylococci, and it manifests synergy with numerous SOC antibiotics. Additionally, resistance to F12 and β-lactam antibiotics appears mutually exclusive, and, importantly, we provide evidence that F12 resensitizes normally resistant MRSA strains to β-lactams both in vitro and in vivo These results suggest that combinations of F12 and SOC antibiotics are a promising new approach to treating refractory S. aureus infections.

Zinc oxide nanoparticles prevent multidrug resistant Staphylococcus-induced footpad dermatitis in broilers

ABSTRACT The current experiment was designed to evaluate the effects of dietary supplementations of zinc oxide nanoparticles (ZONPs) on some behavioural, performance, welfare and histopathological changes in broilers exposed to multidrug resistant Staphylococcus aureus (MRSA)-induced footpad dermatitis (FPD). Eighty-four male Indian River (IR) broilers were randomly allotted to six different dietary treatments as follows: C−ve, C+ve, 10, 20, 30 and 40 ppm ZONPs from 7 to 49d of age. At day 28, broilers (n = 70) were sub-cutaneously injected with 0.5 ml of saline containing 5.3 × 107 CFU/ml of S. aureus (MRSA) in each metatarsal foot pad. Control (non-infected) broilers were given 0.5 ml of saline (n = 14). Results clarified that non-infected birds and ZONPs-fed birds had significantly higher standing and feeding activities and lower resting activities in comparison with the infected group. Also, the S. aureus infected group had significantly lower body weight gain (BWG) and higher feed conversion ratio (FCR) than the non-infected group. In addition, the non-infected birds and ZONPs groups had significantly lower object crossing and tonic immobility times (TI) and gait scores (GS) in comparison with the S. aureus group. Only ZONPs 30, 40 ppm and non-infected groups had a significantly higher latency to lie time (LLT) and lower serum cortisol level in comparison with the S. aureus group. Moreover, there were significant changes in the gross lesion score and histopathological lesions between the different groups. In conclusion, the dietary supplementation of ZONPs can reduce S. aureus-induced negative effects of FPD in broilers.

Detection, molecular characterization, and antibiogram of multi-drug resistant and methicillin-resistant Staphylococcus aureus (MRSA) isolated from pets and pet owners in Malaysia.

The emergence of multidrug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA) and multidrug-resistant Staphylococcus aureus (MDRSA) in animals and humans with continuous contact are a great zoonotic concern. This cross-sectional study was performed to investigate the carriage rate, genotypic characteristics, and to determine the antibiogram of S. aureus isolated from pets and pet owners in Malaysia. Nasal and oral swab samples from 40 cats, 30 dogs, and 70 pet owners were collected through convenient sampling. Presumptive colonies on mannitol salt agar were subjected to biochemical identification. S. aureus and MRSA were confirmed by PCR detection of nuc and mecA genes, respectively. Molecular profiles for antimicrobial resistance and virulence genes in S. aureus were also determined. The antibiogram was carried out via Kirby-Bauer test using 18 antibiotics. 17.5% of cats, 20% of dogs, and 27% of pet owners were S. aureus positive. MRSA was also detected in dogs, and pet owners. S. aureus isolates displayed high resistance against penicillin (72.7%), and amoxicillin/clavulanate (66.7%). 39.4% of S. aureus isolates showed multidrug-resistance traits, phenotypically. Molecular characterization of S. aureus revealed the presence of mecA, tetk, tetL, ermA, ermB, ermC, msrA, scn, chp, sak, sep, and sea genes. This study showed the emergence of MRSA and MDRSA in pets and pet owners in Malaysia. The antibiogram findings showed resistance of S. aureus to multiple antibiotics. Furthermore, molecular analysis of immune evasion cluster (IEC) strongly suggests the spread of animal-adapted S. aureus lineages among pets and pet owners.

Loranthus acaciae: Alternative medicine for β-lactamase producer and methicillin-resistant Staphylococcus aureus.

Recently, we reported high antibacterial efficiency of Loranthus acaciae (LA) against different standard strains of bacteria including Methicillin-Resistant Staphylococcus aureus (MRSA). Therefore, this study aimed to confirm the effectiveness of LA against clinically isolated Staphylococcus aureus (SA) including β-lactamase producer (Blac) and MRSA. Forty-eight SA isolates collected from various clinical samples were used in this study. Antibiotics susceptibility profile was determined for twenty different antibiotics using automated Microscan Walkaway 96 Plus system as recommended by Clinical and Laboratory Standards Institute (CLSI) guidelines. This system also identified β-lactamase producers and MRSA. In the meantime, LA ethanolic extract was fractionated using liquid–liquid fraction method to hexane, dichloromethane DCM and methanol 80% fractions. Antimicrobial activities of LA extract and fraction were performed with agar well diffusion method for all SA isolates, MIC and MBC were also recorded. Phytochemical screening for various phyto-constituent classes of LA ethanolic extract was determined. Out of 48 SA isolates, Cefoxitin-positive MRSA represent 31 (64.6%), Blac 17 (35.4%), and 41 (85.4%) were multidrug-resistant SA, which was resistant at least to one antibiotic from three different categories. All isolates were resistant to ampicillin and penicillin. Antimicrobial activities of LA extract and fractions revealed that ethanol extract was active against all isolated SA with inhibition zone ranged from 33 ± 2.00 to 25 ± 3.05 mm. While DCM exhibited the largest inhibition zone range from 37 ± 3.00 to 33 ± 2.00 mm. This study is first of its kind conforming the high antibacterial activity of LA against SA isolated from a different source of infection. The study concluded that LA extract and fractions are active and give positive result for all isolated SA. Therefore, suitable pharmacological formulation of LA extract as a promising antibacterial agent for the treatment of SA infection should be given extreme priority.

Ultrasonic Interfacial Engineering of Red Phosphorous-Metal for Eradicating MRSA Infection Effectively.

Sonodynamic therapy (SDT) is considered to be a potential treatment for various diseases including cancers and bacterial infections due to its deep penetration ability and biosafety, but its SDT efficiency is limited by the hypoxia environment of deep tissues. This study proposes creating a potential solution, sonothermal therapy, by developing the ultrasonic interfacial engineering of metal-red phosphorus (RP), which has an obviously improved sonothermal ability of more than 20 °C elevation under 25 min of continuous ultrasound (US) excitation as compared to metal alone. The underlying mechanism is that the mechanical energy of the US activates the motion of the interfacial electrons. US-induced electron motion in the RP can efficiently transfer the US energy into phonons in the forms of heat and lattice vibrations, resulting in a stronger US absorption of metal-RP. Unlike the nonspecific heating of the cavitation effect induced by US, titanium-RP can be heated in situ when the US penetrates through 2.5cm of pork tissue. In addition, through a sonothermal treatment in vivo, bone infection induced by multidrug-resistant Staphylococcus aureus (MRSA) is successfully eliminated in under 20 min of US without tissue damage. This work provides a new strategy for combating MRSA by strong sonothermal therapy through US interfacial engineering.

Synthesis of high surface area AgNPs from Dodonaea viscosa plant for the removal of pathogenic microbes and persistent organic pollutants

In this study the production of high surface area silver nanoparticles (AgNPs) are reported from the Dodonaea viscosa plant species under controlled condition. The reaction was completed at 40 °C within 5 h and the product was characterized by several advanced techniques such as PXRD, FTIR, TGA, FESEM, XPS, DRS, BET, and UV–Vis. The prepared AgNPs were also evaluated for antimicrobial activities against pathogenic bacteria and fungi such as multi-drug resistant Staphylococcus aureus (MRSA) and Candida albican at a minimum inhibitory concentration (1 μg/mL) with 9 mL of liquid medium (Nutrient Broth). AgNPs were also found to speed up the reduction of organic pollutants such as 2-nitrophenol (2-NP), 4-nitrophenol (4-NP) and azo dyes included Methyl orange (MO), Congo red (CR) and Rhodamine B (RB) which causes pollution. The highest surface area is found for Ag-25 (7.38 m2/g) as compared to others NPs might be the highest catalytic potential of Ag-25.

Marine Sediment-Derived Streptomyces Strain Produces Angucycline Antibiotics against Multidrug-Resistant Staphylococcus aureus Harboring SCCmec Type 1 Gene

The Philippine archipelago is geographically positioned in the tropics with rich areas of marine biodiversity. Its marine sediments harbor actinomycetes that exhibit antibacterial activity. Screening of actinomycetes isolated from marine sediments collected near the coast of Islas de Gigantes, Iloilo showed one isolate that exhibited high activity against the multidrug-resistant Staphylococcus aureus (MRSA) strain carrying the Staphylococcal Cassette Chromosome mec (SCCmec) type 1 gene, a biomarker for drug resistance. The isolate was identified as Streptomyces sp. strain DSD011 based on its 16s rRNA and protein-coding genes (atpD, recA, rpoB, and trpB) sequences, and was found to be a new species of salt-tolerant marine Streptomyces. Further, the strain harbors both non-ribosomal peptide synthetase (NRPS) and type II polyketide synthase (PKS) in its genome. The targeted chromatographic isolation and chemical investigations by Liquid Chromatography Mass Spectrometry-Time of Flight (LCMS-TOF), tandem mass spectrometry (MS/MS), and Global Natural Product Social molecular networking (GNPS) of the antibiotics produced by the strain afforded the two polycyclic aromatic polyketide angucycline glycosides, fridamycin A (1) and fridamycin D (2), which are products of type II PKS biosynthesis. Compounds 1 and 2 displayed antibacterial activity against MRSA with minimum inhibitory concentration (MIC) of 500 μg/mL and 62.5 μg/mL, respectively. These results suggest that the underexplored marine sediments near the coast of Islas de Gigantes, Iloilo offer access to undiscovered Streptomyces species that are invaluable sources of antibiotic leads.

Antibacterial Anacardic Acid Derivatives.

We report on the antibacterial activity of five phenolic lipids derived from anacardic acid characterized by increasing alkyl chain lengths with 6, 8, 10, 12, or 14 carbon atoms. The compounds were profiled for their physicochemical properties, transport across epithelial monolayers, cytotoxicity, and antibacterial activity as compared to common antibiotics. No cytotoxicity was reported in cell lines of fibroblast, hepatic, colorectal, or renal origin. C10 and C12 significantly increased the survival in a Galleria mellonella model infected with multi-drug-resistant Staphylococcus aureus (MRSA) or vancomycin-resistant Enterococci (VRE) as compared to the untreated control group. Future studies are required to corroborate these findings in relevant animal model systems of infection.