The Effect of Culture Condition on Type 5 Capsular Polysaccharide Production of Staphylococcus aureus from Diary Cattle

[Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and laid foundation for carrying out new polysaccharide vaccine research. [Method] Staph-ylococcus aureus was isolated from milk sample of sick dairy cattle and capsular polysaccharide serotypes were identified. Type 5 capsular polysaccharide was cultured on BHI,solid columbia and mod110 culture media. Glucose and lactose were taken as carbon sources for every culture media in solid and liquid state. Therefore 9 different culture conditions were taken to study the effect of culture conditions on capsular polysaccharide production. [Result] Different culture conditions indicated that compared with columbia culture media, BHI culture media could decline capsular polysaccharide production and mod110 culture media could increase capsular polysaccharide production. While for same culture media, solid culture media was better for capsular polysaccharide production,meanwhile,taken lactose as carbon source could increase capsular polysaccharide production.

Elimination of methicillin‑resistant Staphylococcus aureus biofilms on titanium implants via photothermally‑triggered nitric oxide and immunotherapy for enhanced osseointegration

Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.

Eugenol targeting CrtM inhibits the biosynthesis of staphyloxanthin in Staphylococcus aureus

Staphylococcus aureus is a serious foodborne pathogen threatening food safety and public health.Especially the emergence of methicillin-resistant Staphylococcus aureus(MRSA)increased the difficulty of S.aureus treatment.Staphyloxanthin is a crucial virulence factor of S.aureus.Blocking staphyloxanthin production could help the host immune system counteract the invading S.aureus cells.In this study,we first screened for staphyloxanthin inhibitors using a virtual screening method.The outcome of the virtual screening method resulted in the identification of eugenol(300μg/mL),which significantly inhibits the staphyloxanthin production in S.aureus ATCC 29213,S.aureus Newman,MRSA ATCC 43300 and MRSA ATCC BAA1717by 84.2%,63.5%,68.1%,and 79.5%,respectively.The outcome of the growth curve assay,field-emission scanning electron,and confocal laser scanning microscopy analyses confirmed that eugenol at the test concentration did not affect the morphology and growth of S.aureus.Moreover,the survival rate of S.aureus ATCC 29213 and MRSA ATCC 43300 under H_(2)O_(2) pressure decreased to 51.9%and 45.5%in the presence of eugenol,respectively.The quantitative RT-PCR and molecular simulation studies revealed that eugenol targets staphyloxanthin biosynthesis by downregulating the transcription of the crtM gene and inhibiting the activity of the CrtM enzyme.Taken together,we first determined that eugenol was a prominent compound for staphyloxanthin inhibitor to combat S.aureus especially MRSA infections.

The ever-changing microenvironment of Staphylococcus aureus in cutaneous infections

Background:Staphylococcus aureus is responsible for the majority of skin and soft tissue infections,which are often diagnosed at a late stage,thereby impacting treatment efficacy.Our study was designed to reveal the physiological changes at different stages of infection by S.aureus through the combined analysis of variations in the skin microenvironment,providing insights for the diagnosis and treatment of S.aureus infections.Methods:We established a murine model of skin and soft tissue infection with S.aureus as the infectious agent to investigate the differences in the microenvironment at different stages of infection.By combining analysis of the host immune status and histological observations,we elucidate the progression of S.aureus infection in mice.Results:The results indicate that the infection process in mice can be divided into at least two stages:early infection(1–3 days post-i nfection)and late infection(5–7 days post-i nfection).During the early stage of infection,notable symptoms such as erythema and abundant exudate at the infection site were observed.Histological examination revealed infiltration of numerous neutrophils and bacterial clusters,accompanied by elevated levels of cytokines(IL-6,IL-10).There was a decrease in microbial alpha diversity within the microenvironment(Shannon,Faith's PD,Chao1,Observed species,Simpson,Pielou's E).In contrast,during the late stage of infection,a reduction or even absence of exudate was observed at the infected site,accompanied by the formation of scabs.Additionally,there was evidence of fibroblast proliferation and neovascularization.The levels of cytokines and microbial composition gradually returned to a healthy state.Conclusion:This study reveals synchrony between microbial composition and histological/immunological changes during S.aureus-i nduced SSTIs.

Assessment of the inhibitory effects of sodium nitrite, nisin, potassium sorbate, and sodium lactate on Staphylococcus aureus growth and staphylococcal enterotoxin A production in cooked pork sausage using a predictive growth model

This study was conducted to analyze the effects of sodium nitrite,nisin,potassium sorbate,and sodium lactate against Staphylococcus aureus(S.aureus)growth and staphylococcal enterotoxins(SEs)production in cooked pork sausage by inoculating sausage samples containing preservative with an S.aureus strain producing staphylococcal enterotoxin A(SEA)and then storing them at 37℃ for 36 h.Samples were analyzed every 3 h to count the S.aureus colonies and to detect SEA.The modified Gompertz model was used to describe S.aureus growth in the samples under various conditions,and the preservatives with a significant antimicrobial effect were selected.In addition,the antimicrobial effects of the selected preservatives under various concentrations were tested.Results showed that sodium nitrite,nisin,and potassium sorbate had a weak effect against S.aureus growth and had no effect against SEA production,whereas sodium lactate could significantly inhibit S.aureus growth and SEA production.Moreover,the antimicrobial effect of sodium lactate was concentration-dependent,wherein sodium lactate concentration<12 g/kg showed no inhibitory effect,but when the concentration was increased to 24 g/kg,sodium lactate could effectively inhibit S.aureus growth and SEA production,and at 48 g/kg,sodium lactate had a significant inhibitory effect.

Infectious Spondylitis-Associated Staphylococcus aureus with Virulence Gene pvl or tst Causes More Necrosis than Apoptosis in Human Alveolar Basal Epithelial Cell Line A549

Methicillin-sensitive and resistant Staphylococcus aureus (MSSA and MRSA, respectively) can cause non-tuberculosis infectious spondylitis. In 43 cases of bacterial infectious spondylitis, Mycobacterium tuberculosis and S. aureus were the two major causative pathogens. MRSA caused more anterior operations and thoracic infections, while MSSA caused more posterior infections and lumbar infections. Differences between six S. aureus isolates from infectious spondylitis were characterized. MLST and staphylococcal cassette chromosome mec (SCCmec) analysis identified MSSA ST959 and ST30 isolates, MRSA ST239/SCCmec IIIA isolates 2 and 3, ST59/SCCmec IIIA-like isolate 6, and ST30/SCCmec IV isolate 5. While all of the isolates were resistant to penicillin and ampicillin, the MRSA isolates were more resistant than the MSSA isolates. Carbapenem-resistant MRSA ST239/SCCmec IIIA and ST59/SCCmec IIIA-like isolates of the agr1 type were also resistant to clindamycin and erythromycin. Leukocidin genes (pvl or lukED) and hemolysin genes (hla, hld and hlg) were present in all of the isolates. All six isolates caused more necrosis than apoptosis in the human alveolar basal epithelial cell line A549;however, ST59/SCCmec IIIA-like isolate 6, ST30/ SCCmec IV isolate 5 with pvl genes, and MSSA ST30 isolates with tst caused greater than 40% cell death after the 4-h incubation. Regardless of the MRSA isolate and its SCCmec type or the MSSA isolate, the infectious spondylitis-associated S. aureus isolates differed genetically, and the pvl and tst genes may be important genes for cell necrosis.

Co-Habitation of <i>Staphylococcus lugdunensis</i>with <i>Staphylococcus aureus</i>Resistant to Methicillin and Vancomycin in the Nasal Snares of Laboratory Rats

The public health problem created by multidrug resistant bacteria in the 21st century continues to receive attention by researchers all over the world. As the production of new antibiotics is not commeasurable with the rate of evolvement of MDR bacteria, the news of a proposed new antibiotic “Lugdunin” is much awaited and a welcomed development. Lugdunin is produced by Staphylococcus lugdunensis and has the ability to kill S. aureus. Both bacteria are nasal colonizers. The present investigation looks into the antibiotic susceptibility pattern of co-habitation of S. lugdunensis with methicillin and vancomycin resistant Staphylococcus aureus in laboratory bred Wister rats. Nasal swabs of anaesthetized rats were collected using a sterile cotton swab moistened in 0.9% saline solution. All swabs were inoculated into nutrient broth, cultured at 37°C for 24 hrs. Overnight bacterial growth plated on blood agar and incubated at 37°C for 24 hrs. Organism identification and antibiotic susceptibility test were by using BioMerieux VITEK 2 compact automated system (BioMerieux, Marcy I’Etoile France), according to the manufacturers guidelines. Results obtained showed co-habitation of S. aureus with co-agulase negative bacteria, inclusive of S. lugdunensis. All the isolates were resistant to methicillin with a 33.3% resistance to vancomycin. The difference between the number of antibiotic resistant or sensitive varied statistically among the Staphylococcal isolates. For S. aureus 1, the difference was significant with p-value 0.034 but not significant for isolates 2, 3 and 4 with p-values of 0.158, 0.477 and 0.158 respectively. A statistically significant difference was seen with S. lugdunensis. The result from the study therefore, showed that the colonization of the nasal snares of the laboratory bred rats with S. aureus and other co-agulase negative Staphylococci was not affected by the presence of S. lugdunensis.

Comparative Study of Synergistic Effects of Antibiotics with Triangular Shaped Silver Nanoparticles, Synthesized Using UV-Light Irradiation, on <i>Staphylococcus aureus</i>and <i>Pseudomonas aeruginosa</i>

In the present work, a comparative study of antibacterial activity and synergistic effects of triangular silver nanoparticles in combination with two standard antibiotics is discussed for Staphylococcus aureus and Pseudomonas aeruginosa. A green route was developed to synthesise silver nanoparticles in which silver oxalate was taken as precursor, black tea leaves extract as surfactant and chitin as a stabilizing agent. A grey coloured colloidal solution of silver nanoparticles was obtained which was characterized by using various techniques like X-ray diffractometer (XRD), transmission electron microscopy (TEM) and UV-visible spectroscopy. Anti-bacterial studies gave approximately equal inhibition zones for both the combinations which states that silver nanoparticles are to be equally effective and synergistic effects were clearly observed in case of P. aeruginosa.

Screening agars for MRSA:evaluation of a stepwise diagnostic approach with two different selective agars for the screening for methicillin-resistant Staphylococcus aureus(MRSA)

Background: Colonization with methicillin-resistant Staphylococcus aureus(MRSA) poses a hygiene risk that does not spare field hospitals or military medical field camps during military deployments. Diagnostic options for unambiguously identifying MRSA isolates are usually scarce in military environments. In this study, we assessed the stepwise application of two different selective agars for the specific identification of MRSA in screening analyses.Methods: Nasal swabs from 1,541 volunteers were subjected to thioglycollate broth enrichment and subsequently screened on CHROMagar MRSA selective agar for the identification of MRSA. The MRSA identity of suspiciouslooking colonies was confirmed afterwards or excluded by another selective agar, chrom ID MRSA. All isolates from the selective agars with MRSA-specific colony morphology were identified by biochemical methods and mass spectrometry.Results: The initial CHROMagar MRSA screening identified suspicious colonies in 36 out of 1541 samples. A total of 25 of these 36 isolates showed MRSA-like growth on chrom ID agar. Out of these 25 isolates, 24 were confirmed as MRSA, while one isolate was identified as Staphylococcus kloosii. From the 11 strains that did not show suspicious growth on chrom ID agar, 3 were methicillin-sensitive Staphylococcus aureus(MSSA, with one instance of cocolonization with Corynebacterium spp.), 2 were confirmed as MRSA(with 1 instance of co-colonization with MSSA), 2 were lost during passaging and could not be re-cultured, one could not be identified by the applied approaches, and the remaining 3 strains were identified as Staphylococcus saprophyticus, Staphylococcus hominis(co-colonized with Macrococcus caseolyticus) and Staphylococcus cohnii, respectively.Conclusion: The application of the selective agar CHROMagar MRSA alone proved to be too non-specific to allow for a reliable diagnosis of the presence of MRSA. The combined use of two selective agars in a stepwise approach reduced this non-specificity with an acceptably low loss of sensitivity. Accordingly, such a stepwise screening approach might be an option for resource-restricted military medical field camps.

Therapeutic Potential of Staphylococcal Bacteriophages for Nasal Decolonization of <i>Staphylococcus aureus</i>in Mice

Bacteriophages represent a rich and unique resource of anti-infectives to counter the global problem of antibiotic resis- tance. In this work, we assessed the bactericidal activity of two virulent staphylococcal phages, K and 44AHJD, against S. aureus isolates of clinical significance, and tested their efficacy in vivo. The phage cocktail lysed >85% of the clinical isolates tested. Both the phages were purified by ion-exchange column chromatography following propagation in bioreactors. The purity profiles of the ion-exchange purified phages were compared with those of phages purified using cesium chloride density gradient ultracentrifugation, and infectiousness of the purified phages was confirmed by plaque forming assay. The in vivo efficacy of a phage cocktail was evaluated in an experimental murine nasal colonization model, which showed that the phage cocktail was efficacious. To our knowledge, this is the first report of phage use in an in vivo model of nasal carriage.

甘草提取物对Staphylococcus aureus的抑菌活性及作用机理

食源性病菌为食品安全带来了巨大挑战,甘草提取物作为食品添加剂对金黄色葡萄球菌(Staphylococcus aureus)具有良好的抑菌作用,可作为天然食品防腐剂的候选原料,但目前对其抑菌机理的研究还不深入,影响了其应用。为探究甘草提取物对S.aureus的抑菌机理,该研究通过生长曲线、氧化损伤实验、细胞膜壁分析、蛋白质分析和DNA分析,评价了甘草提取物对S.aureus的抑菌作用机制。结果表明,甘草提取物导致S.aureus核酸渗漏,说明其膜完整性被破坏;同时,甘草提取物降低了几种能量代谢酶:琥珀酸脱氢酶(succinate dehydrogenase,SDH)和总ATP酶的活力;此外,光谱和竞争分析表明,甘草提取物与DNA发生了静电结合和凹槽结合。总之,甘草提取物主要是通过对S.aureus细胞壁膜、蛋白质合成、细菌代谢活力和遗传物质发挥作用,从而抑制其生长。该研究为甘草提取物在食品防腐方面的应用提供了理论基础。

金黄色葡萄球菌(Staphylococcus aureus)液体增菌培养基的优化

为研发一种金黄色葡萄球菌(Staphylococcus aureus)选择性增菌液,选用针对革兰氏阴性菌及非葡萄球菌属菌株具有选择抑制作用的7.5%氯化钠肉汤作为基础培养基,探索氨基酸、丙酮酸钠、甘露醇对金黄色葡萄球菌的促生长能力,通过正交试验确定培养基的最优配方,并使用优化后的培养基与原始培养基作用于来源不同的四株金黄色葡萄球菌标准菌株,对其增菌效果和抑制大肠杆菌(Escherichia coli)的效果进行对比。结果表明,最佳培养基配方为在基础培养基上添加L-丙氨酸1.0 g/L、甘露醇6.0 g/L、丙酮酸钠1.2 g/L。菌株在优化后培养基上增菌浊度及转接至Baird-Parker的菌落数上均有促进效果,最终菌株的OD550 nm值有0.28~0.34的增长,转接Baird-Parker后的菌落数也有10~100倍的增长,且在促进目标菌生长的同时对大肠杆菌的抑制性也没有受到影响,表明该增菌培养基选择性良好。

Prevalence and antibiogram study of Salmonella and Staphylococcus aureus in poultry meat

Objective:To evaluate the presence and antibiogram pattern of Salmonella and Staphylococcus aureus(S.aureus)in retail poultry meat products.Methods:Foodborne pathogens(Salmonella and S.aureus)were isolated from poultry meat and confirmed with the help of biochemical and immunological test.Antibiogram of the isolates were examined by following CLS1 methods.Results:A total number of 209 poultry meat samples were collected and studied in this study.Out of which,5.26%were found contaminated with Salmonella while 18.18%were found contaminated with S.aureus.All the Salmonella and S.aureus isolates were found resistant to at least one antibiotic.About 72.72%of the Salmonella isolates showed resistance to tetracycline,while S.aureus isolates were also found highly resistant to tetracycline equal to 44.73%.One of the Salmonella isolates showed multi-drug resistance to almost six antibiotics out of nine antibiotics used in the study.Multidrug resistant S.aureus isolates were also found in the study.Conclusions:The study confirmed the presence of Salmonella and S.aureus in retail poultry meat.It is a potential threat to consumer health.To reduce the risk of contamination,good hygiene practices are necessary from processing to storage.

Antibacterial activity of the essential oils from the leaves of Eucalyptus globulus against Escherichia coli and Staphylococcus aureus

Objective:To examine the in vitro antimicrobial activities of essential oil of the leaves of Eucalyptus globulus(E.globulus).Methods:The essential oils of this plant were obtained by the hydrodistillation method.The inhibitory effects of this essential oil were tested against Escherichia coli(E.coli)and Staphylococcus aureus(S.aureus)by using agar disc diffusion and dilution broth methods.Results:The results obtained showed that essential oil of the leaves of E.globulus has antimicrobial activity against gram negative bacteria(E.coli)as well as gram positive bacteria(S.aureus).Conclusion:The encouraging results indicate the essential oil of E.globulus leaves might be exploited as natural antibiotic for the treatment of several infectious diseases caused by these two germs,and could be useful in understanding the relations between traditional cures and current medicines.

Detection of Staphylococcus aureus in Dairy Products by Polymerase Chain Reaction Assay

A polymerase chain reaction （PCR） assay was employed for direct detection of Staphylococcus aureus without enrichment in dairy products. A solvent extraction procedure was successfully modified for the extraction of Staphylococcus aureus DNA from artificially contaminated whole milk, skim milk, and cheese. A primer targeting the thermostable nuclease gene （nuc） was used in the PCR. A DNA fragment of 279 bp was amplified. The PCR product was confirmed by DNA sequencing. In this study, the PCR, GB-4789.10-94, Perifilm RSA.Count Plate, and Baird-Parker ＋ RPF Agar were compared. The sensitivity of the PCR was 10 CFU mL^-1 of whole milk, skim milk, and 55 CFU g^-1 of cheese. The developed methodology allowed for detection of Staphylococcus aureus in dairy products in less than 6 h. The time taken for the development of this PCR assay was 12-24 h, less than the time taken by the general PCR assay using the enrichment method, and the coincidence rate of this developed PCR was 94.3%, the sensitivity was 100%. It was a rapid, sensitive, and effective method for PCR to detect Staphylococcus aureus in milk and milk products.

Antimicrobial activity and synergism of Sami-Hyanglyun-Hwan with ciprofloxacin against methicillin-resistant Staphylococcus aureus

Objective: To investigate the antibacterial activity of SHHextracted with either water or ethanol against methicillin-resistant Staphylococcus aureus(MRSA) and combinatory antimicrobial effect with ciprofloxacin(CIP) by time kill assay and checkerboard dilution test. Methods: The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan(SHH) water extract(SHHW) and SHH ethanol extract(SHHE) ranged from 250 to 2000 μg/m L and 125 to 1000 μg/m L against MRSA, respectively. Results: In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h. Conclusions: The present study demonstrates the therapeutic ability of SHHE against MRSA infections.

The growth of Staphylococcus aureus and Escherichia coli in low-direct current electric fields

Electrical potentials up to 800 mV can be observed between different metallic dental restorations. These potentials produce fields in the mouth that may interfere with microbial communities. The present study focuses on the impact of different electric field strengths （EFS） on the growth of Staphylococcus aureus （ATCC 25923） and Escherichia coil （ATCC 25922） in vitro. Cultures of S. aureus and E. coil in fluid and gel medium were exposed to different EFS. Effects were determined by calculation of viable counts and measurement of inhibition zones. In gel medium, anodic inhibition zones for S. aureuswere larger than those for E. coliat all field strength levels. In fluid medium, the maximum decrease in the viable count of S. aureus cells was at 10 V.m-1. Field-treated S. aureus cells presented ruptured cell walls and disintegrated cytoplasm. Conclusively, S. aureus is more sensitive to increasing electric field strength than E. coll.

Staphylococcus aureus and biofilms:transmission, threats, and promising strategies in animal husbandry

Staphylococcus aureus(S. aureus) is a common pathogenic bacterium in animal husbandry that can cause diseases such as mastitis, skin infections, arthritis, and other ailments. The formation of biofilms threatens and exacerbates S. aureus infection by allowing the bacteria to adhere to pathological areas and livestock product surfaces, thus triggering animal health crises and safety issues with livestock products. To solve this problem, in this review, we provide a brief overview of the harm caused by S. aureus and its biofilms on livestock and animal byproducts(meat and dairy products). We also describe the ways in which S. aureus spreads in animals and the threats it poses to the livestock industry. The processes and molecular mechanisms involved in biofilm formation are then explained. Finally, we discuss strategies for the removal and eradication of S. aureus and biofilms in animal husbandry, including the use of antimicrobial peptides, plant extracts, nanoparticles, phages, and antibodies. These strategies to reduce the spread of S. aureus in animal husbandry help maintain livestock health and improve productivity to ensure the ecologically sustainable development of animal husbandry and the safety of livestock products.

Teicoplanin combined with conventional vancomycin therapy for the treatment of pulmonary methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis infections

BACKGROUND Vancomycin and teicoplanin are both antibiotics that have significant antimicrobial effects on Gram-positive cocci.AIM To explore the value of teicoplanin combined with conventional(vancomycin only)anti-infective therapy for the treatment of methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis pulmonary infections.METHODS A total of 86 patients with methicillin-resistant Staphylococcus aureus or methicillin-resistant Staphylococcus epidermidis pulmonary infections,treated in our hospital between January 2018 and February 2020,were assigned to the study and control groups using a random number table method,with 43 patients in each group.The control group received conventional treatment(vancomycin),and the study group received both teicoplanin and conventional treatment.The following indicators were assessed in both groups:the time required for symptom relief,treatment effectiveness,serum levels of inflammatory factors(procalcitonin,interleukin-1β,tumor necrosis factor-α,C-reactive protein),clinical pulmonary infection scores before and after treatment,and the incidence of adverse reactions.RESULTS Patients in the study group were observed to have faster cough and expectoration resolution,white blood cell count normalization,body temperature normalization,and rales disappearance than patients in the control group(all P<0.05);the total rate of effectiveness was 93.02%in the study group,higher than the 76.74%in the control group(P<0.05).The pre-treatment serum levels of procalcitonin,interleukin-1β,tumor necrosis factor-α,and C-reactive protein as well as the clinical pulmonary infection scores were similar among the patients in both groups.However,the post-treatment serum levels of procalcitonin,interleukin-1β,tumor necrosis factor-α,and C-reactive protein as well as the clinical pulmonary infection scores were significantly lower in the study group than in the control group(P<0.05).There was no significant difference in the incidence of adverse reactions between the groups.CONCLUSION Compared with conventional(vancomycin only)therapy,teicoplanin and vancomycin combination therapy for patients with pulmonary methicillinresistant Staphylococcus aureus and methicillin-resistant Staphylococcus epidermidis infections can improve patient clinical symptoms,modulate serum inflammatory factor levels,and improve treatment efficacy,without increasing the risk of adverse reactions.

Quinosumycin,a novel anti-MRSA thioether-linked quinolinone-quinazolinone heterodimer from a marine actinomycete Streptomyces diastaticus NBU2966

Marine natural products offer a promising source in the development of new antibiotic drugs.Two previously undescribed compounds,including one sulfur-bearing alkaloid named quinosumycin(1)along with one chromone derivative namely chromycone(2),were discovered from an ethyl acetate(EtOAc)extract of marine Streptomyces diastaticus NBU2966 through a bioactivity-guided isolation prioritized for antimicrobial potential.The analysis of nuclear magnetic resonance(NMR)spectroscopy,high resolution electrospray ionization mass spectroscopy(HRESIMS)data,and electronic circular dichroism(ECD)calculations enabled the elucidation of their structures and the determination of their absolute configurations.Quinosumycin(1)is the first heterodimer scaffold incorporating quinolinone and quinazolinone motifs coupled by a thioether bond.Interestingly,Compound 1 exhibited a relatively selective growth inhibition against methicillin-resistant Staphylococcus aureus(MRSA)with the minimal inhibitory concentration(MIC)value of 8μg/mL.