To understand the clinical characteristics of Staphylococcus aureus bloodstream infection and the main risk factors affecting clinical prognosis, providing a reference for clinical prevention and control of Staphylococcus aureus bloodstream infection. In this study, the clinical data of 152 patients with Staphylococcus aureus bloodstream infection admitted to Guangdong Provincial People's Hospital from January 2019 to December 2021 were retrospectively analyzed by reviewing the electronic medical record system, including underlying diseases, clinical characteristics, risk factors, and bacterial resistance. Statistical methods such as Chi-Squared Test and t Test were used to analyze the related risk factors that may affect the clinical characteristics and prognosis of patients with Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection, then the variables with P<0.05 in univariate analysis were included in the multivariate logistic regression model to analyze the independent risk factors of poor prognosis. The results showed among 152 patients with Staphylococcus aureus bloodstream infection, 50 patients (32.89%) were infected with MRSA. In comparison, 102 patients (67.11%) were infected with methicillin-sensitive Staphylococcus aureus (MSSA). Except for rifampicin, the resistance rate of MRSA to commonly used antibiotics was all higher than that of MSSA, and the difference was statistically significant (Chi-square values were 8.272, 11.972, 4.998, 4.776, respectively;all P-values are less than 0.05). Strains resistant to vancomycin, linezolid, and quinupristin/dalfopristin were not found. In the MRSA group, indwelling catheter and drainage tube, carbapenems, and β-lactamase inhibitor treatment were significantly higher than the MSSA group. The difference was statistically significant (P<0.05). The incidence of poor prognosis of bloodstream infection in the MRSA group was higher than that in the MSSA group (34.00% vs 13.73%), and the difference was statistically significant (χ²=8.495, P<0.05). No independent risk factors associated with poor prognosis were found in the included patients with MRSA bloodstream infection.Multivariate Logistic regression model analysis showed that solid malignant tumors (OR=13.576, 95%CI: 3.352-54.977, P<0.05), mechanical ventilation (OR=7.468, 95%CI: 1.398-39.884, P<0.05) were the most important independent risk factors for poor prognosis in patients with Staphylococcus aureus bloodstream infection. In summary, the poor prognosis rate of MRSA bloodstream infection is higher than that of MSSA. The clinical evaluation of related risk factors should be strengthened, targeted prevention and control interventions should be taken to improve the prognosis of patients with Staphylococcus aureus bloodstream infection, and the use of antibiotics should be rational and standardized, to control bacterial infection and drug resistance effectively .
Humans ; Methicillin-Resistant Staphylococcus aureus ; Staphylococcus aureus ; Retrospective Studies ; Prognosis ; Staphylococcal Infections/microbiology* ; Anti-Bacterial Agents/pharmacology* ; Methicillin/therapeutic use* ; Sepsis

Objective: To explore the impact of traditional Chinese medicine berberine (BBR) on membrane integrity and permeability of Methicillin-resistant Staphylococcus aureus (MRSA) and the change of bacterial cell wall structure, laying a foundation for the clinical application of berberine in antibacterial. Methods: This study used a non-randomized concurrent controlled trial. The 3 MRSA strains were isolated and cultured from lower respiratory tract samples of geriatric patients from Shanghai Eighth People's Hospital between 2019 and 2020.The Meirier VETEK MS fully automated rapid microbial mass spectrometry detection system and VETEK 2 Compact fully automated microbial identification instrument were used to identify bacterial drug sensitivity experiments to detect bacterial species and drug sensitivity. The minimal inhibitory concentration (MIC) of BBR on MRSA strains was determined by broth microdilution. This study used conductivity tests to assess the changes in membrane permeability in response to different concentration of BBR on MRSA, while also investigating the changes in MRSA morphology by transmission electron microscopy. GraphPad Prism5 was used to analyze the differences in the electrical conductivity experimental results. Results: The MIC of BBR on MRSA was 64 μg/ml. After co-culturing MRSA with BBR for 4 h at 8 μg/ml, 16 μg/ml, 32 μg/ml, 64 μg/ml and 128 μg/ml, respectively, the electrical conductivity increased, compared with the control group, by 24.49%,34.59%,208.92%,196.40% and 208.68%, respectively. By transmission electron microscopy, This study found that low concentration of BBR (8 μg/ml,1/8 MIC) caused no significant damage to MRSA, and the bacterial structure of MRSA remained intact. The cell wall of MRSA became thinner after treatment with berberine at medium concentration (64 μg/ml,1 MIC), while high concentration of BBR (512 μg/ml,8 MIC) induced the destruction and dissolution of MRSA cell wall structure and the leakage of bacterial contents, leading to bacterial lysis. Conclusion: Berberine can kill bacteria by altering the permeability of MRSA cell membrane and destroying and dissolving the structure of the cell wall.
Methicillin-Resistant Staphylococcus aureus ; Berberine/pharmacology* ; China ; Anti-Bacterial Agents/pharmacology* ; Cell Membrane ; Microbial Sensitivity Tests

Objective: To explore the impact of traditional Chinese medicine berberine (BBR) on membrane integrity and permeability of Methicillin-resistant Staphylococcus aureus (MRSA) and the change of bacterial cell wall structure, laying a foundation for the clinical application of berberine in antibacterial. Methods: This study used a non-randomized concurrent controlled trial. The 3 MRSA strains were isolated and cultured from lower respiratory tract samples of geriatric patients from Shanghai Eighth People's Hospital between 2019 and 2020.The Meirier VETEK MS fully automated rapid microbial mass spectrometry detection system and VETEK 2 Compact fully automated microbial identification instrument were used to identify bacterial drug sensitivity experiments to detect bacterial species and drug sensitivity. The minimal inhibitory concentration (MIC) of BBR on MRSA strains was determined by broth microdilution. This study used conductivity tests to assess the changes in membrane permeability in response to different concentration of BBR on MRSA, while also investigating the changes in MRSA morphology by transmission electron microscopy. GraphPad Prism5 was used to analyze the differences in the electrical conductivity experimental results. Results: The MIC of BBR on MRSA was 64 μg/ml. After co-culturing MRSA with BBR for 4 h at 8 μg/ml, 16 μg/ml, 32 μg/ml, 64 μg/ml and 128 μg/ml, respectively, the electrical conductivity increased, compared with the control group, by 24.49%,34.59%,208.92%,196.40% and 208.68%, respectively. By transmission electron microscopy, This study found that low concentration of BBR (8 μg/ml,1/8 MIC) caused no significant damage to MRSA, and the bacterial structure of MRSA remained intact. The cell wall of MRSA became thinner after treatment with berberine at medium concentration (64 μg/ml,1 MIC), while high concentration of BBR (512 μg/ml,8 MIC) induced the destruction and dissolution of MRSA cell wall structure and the leakage of bacterial contents, leading to bacterial lysis. Conclusion: Berberine can kill bacteria by altering the permeability of MRSA cell membrane and destroying and dissolving the structure of the cell wall.
Methicillin-Resistant Staphylococcus aureus ; Berberine/pharmacology* ; China ; Anti-Bacterial Agents/pharmacology* ; Cell Membrane ; Microbial Sensitivity Tests

Objective: To explore the effects and mechanism of water-soluble chitosan hydrogel on infected full-thickness skin defect wounds in diabetic mice. Methods: The experimental research method was adopted. The control hydrogel composed of polyvinyl alcohol and gelatin, and the water-soluble chitosan hydrogel composed of the aforementioned two materials and water-soluble chitosan were prepared by the cyclic freeze-thaw method. The fluidity of the two dressings in test tube before and after the first freeze-thawing was generally observed, and the difference in appearance of the final state of two dressings in 12-well plates were compared. According to random number table (the same grouping method below), the cell strains of L929 and HaCaT were both divided into water-soluble chitosan hydrogel group and control hydrogel group, respectively. After adding corresponding dressings and culturing for 24 h, the cell proliferation activity was measured using cell counting kit 8. Rabbit blood erythrocyte suspensions were divided into normal saline group, polyethylene glycol octyl phenyl ether (Triton X-100) group, water-soluble chitosan hydrogel group, and control hydrogel group, which were treated accordingly and incubated for 1 hour, and then the hemolysis degree of erythrocyte was detected by a microplate reader. Twenty-four female db/db mice aged 11-14 weeks were selected, and full-thickness skin defect wounds on their backs were inflicted and inoculated with the methicillin-resistant Staphylococcus aureus (MRSA), 72 h later, the mice were divided into blank control group, sulfadiazine silver hydrogel group, control hydrogel group, and water-soluble chitosan hydrogel group, which were treated accordingly. On post injury day (PID) 0 (immediately), 7, 14, and 21, the healing of the wound was observed. On PID 14 and 21, the wound healing rate was calculated. On PID 14, MRSA concentration in wounds was determined. On PID 21, the wounds were histologically analyzed by hematoxylin and eosin staining; the expression of CD31 in the wounds was detected by immunofluorescence method, and its positive percentage was calculated. Raw264.7 cells were taken and divided into interleukin-4 (IL-4) group, blank control group, control hydrogel group, and water-soluble chitosan hydrogel group, which were treated accordingly. At 48 h of culture, the percentages of CD206 positive cells were detected by flow cytometry. The number of samples was all 3. Data were statistically analyzed with independent sample t test, one-way analysis of variance, analysis of variance for repeated measurement, least significant difference test, and Dunnett T3 test. Results: Two dressings in test tube had certain fluidity before freeze-thawing and formed semi-solid gels after freeze-thawing for once. The final forms of two dressings in 12-well plates were basically stable and translucent sheets, with little difference in transparency. At 24 h of culture, the cell proliferation activities of L929 and HaCaT in water-soluble chitosan hydrogel group were significantly higher than those in control hydrogel group (with t values of 6.37 and 7.50, respectively, P<0.01). At 1 h of incubation, the hemolysis degree of erythrocyte in water-soluble chitosan hydrogel group was significantly lower than that in Triton X-100 group (P<0.01), but similar to that in normal saline group and control hydrogel group (P>0.05). On PID 0, the traumatic conditions of mice in the 4 groups were similar. On PID 7, more yellowish exudates were observed inside the wound in blank control group and control hydrogel group, while a small amount of exudates were observed in the wound in sulfadiazine silver hydrogel group and water-soluble chitosan hydrogel group. On PID 14, the wounds in blank control group and control hydrogel group were dry and crusted without obvious epithelial coverage; in sulfadiazine silver hydrogel group, the scabs fell off and purulent exudate was visible on the wound; in water-soluble chitosan hydrogel group, the base of wound was light red and obvious epithelial coverage could be observed on the wound. On PID 14, the wound healing rate in water-soluble chitosan hydrogel group was significantly higher than that in the other 3 groups (all P<0.01). On PID 21, the wound in water-soluble chitosan hydrogel group was completely closed, while the wounds in the other 3 groups were not completely healed; the wound healing rate in water-soluble chitosan hydrogel group was significantly higher than that in the other 3 groups (all P<0.01). On PID 14, the concentration of MRSA in the wound in water-soluble chitosan hydrogel group was significantly lower than that in blank control group (P<0.01), but similar to that in control hydrogel group and sulfadiazine silver hydrogel group (P>0.05). On PID 21, the new epidermis was severely damaged in blank control group; the epidermis on the wound in control hydrogel group also had a large area of defect; complete new epidermis had not yet being formed on the wound in sulfadiazine silver hydrogel group; the wound in water-soluble chitosan hydrogel group was not only completely covered by the new epidermis, the basal cells of the new epidermis were also regularly aligned. On PID 21, the percentage of CD31 positivity in the wound in water-soluble chitosan hydrogel group was (2.19±0.35)%, which was significantly higher than (0.18±0.05)% in blank control group, (0.23±0.06)% in control hydrogel group, and (0.62±0.25)% in sulfadiazine silver hydrogel group, all P<0.01. At 48 h of culture, the percentage of CD206 positive Raw264.7 cells in water-soluble chitosan hydrogel group was lower than that in IL-4 group (P>0.01) but significantly higher than that in blank control group and control hydrogel group (P<0.05 or P<0.01). Conclusions: The water-soluble chitosan hydrogel has good biosafety and can induce higher level of macrophage M2 polarization than control hydrogel without water-soluble chitosan, so it can enhance the repair effect of MRSA-infected full-thickness skin defect wounds in diabetic mice and promote rapid wound healing.
Mice ; Female ; Animals ; Rabbits ; Interleukin-4 ; Hydrogels/pharmacology* ; Wound Healing ; Chitosan/pharmacology* ; Diabetes Mellitus, Experimental ; Water ; Methicillin-Resistant Staphylococcus aureus ; Gelatin ; Polyvinyl Alcohol ; Hemolysis ; Saline Solution ; Eosine Yellowish-(YS) ; Hematoxylin ; Octoxynol ; Silver ; Phenyl Ethers ; Sulfadiazine

A new phloroglucinol was isolated from 50% ethanol extract of Dryopteris fragrans by silica gel column chromatography, Sephadex LH-20 gel column chromatography, thin-layer chromatography(TLC), and preparative liquid column chromatography. On the basis of MS, ~1H-NMR, ~(13)C-NMR, and reference materials, compound 1 was identified as 2,5-cyclohexadien-1-one, 2-{[2,6-dihydroxy-4-methoxy-3-methyl-5-(1-isobutyl)phenyl]methyl}-3,5-dihydroxy-4,4-dimethyl-6-(1-oxobutyl)(1), and named disaspidin BB. Compound 1 was evaluated for its antibacterial activity. The experimental results showed that compared with the commonly used topical antibiotics erythromycin or mupirocin, disaspidin BB exhibited significant antibacterial activities against Staphylococcus epidermidis(SEP), S. haemolyticus(SHA), and methicillin-resistant S. aureus(MRSA)(P<0.05). Additionally, disaspidin BB was sensitive to ceftazidime-resistant SEP1-SEP4, SHA5-SHA7, MRSA8, and MRSA9. The MIC values of disaspidin BB against SEP and SHA were 1.67-2.71 μg·mL~(-1) and 10.00-33.33 μg·mL~(-1) respectively. Disaspidin BB has good antibacterial activities and deserves development as a new anti-infective drug for external use.
Anti-Bacterial Agents/pharmacology* ; Dryopteris ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Phloroglucinol/pharmacology* ; Plant Extracts/pharmacology*

Objective: To analyze the Staphylococcal enterotoxins, Staphylococcal enterotoxin genes, drug resistance and molecular typing of 41 Staphylococcus aureus isolates from 2 food-borne illness outbreaks on 21 August and 27 September 2020 in Guangzhou. Methods: A total of 41 Staphylococcus aureus isolates from 2 outbreaks were analyzed by multilocus sequence typing (MLST) and spa typing. The Staphylococcal enterotoxins typing and the Staphylococcal enterotoxin genes of the isolates were analyzed by ELISA and PCR, respectively. The antimicrobial susceptibility of the isolates was performed by disc diffusion. 21 Staphylococcus aureus isolates were characterized using whole genome sequencing (WGS). Based on the whole genome single nucleotide polymorphism (SNP), the phylogenetic tree was constructed by Snippy. Results: 41 Staphylococcus aureus isolates were divided into 2 types by MLST and spa typing: ST6-t701 and ST7-t091. 2 ST7-t091 isolates were identified as methicillin-resistant Staphylococcus aureus (MRSA). 25 ST7-t091 isolates and 14 ST6-t701 isolates were methicillin-sensitive Staphylococcus aureus (MSSA), and were resistant to 7 and 6 antibiotics, respectively. All isolates were positive for sea by PCR. WGS revealed all 21 isolates carried scn, sak, sea, hla, hld, hlgA, hlgB, hlgC, lukD virulence genes. The results showed the isolates contained an immune evasion cluster type D which located in bacteriophage ϕSa3. The SNP phylogenetic tree showed 2 MRSA ST7-t091 were constituted a separate clade from the 12 MSSA ST7-t091 isolates and 7 ST6-t701 isolates showed high similarity to each other. Conclusion: Base on the results of phylogenetic analysis, the 2 food-borne illness outbreaks occurred on 21 August and 27 September 2020 are caused by the combination of the MRSA ST7-t091 strain and the MSSA ST7-t091 strain, and the MSSA ST6-t701 strain, respectively. All isolates have high level of antibiotic resistance and carry high virulent genes.
Anti-Bacterial Agents/pharmacology* ; Disease Outbreaks ; Foodborne Diseases/epidemiology* ; Humans ; Methicillin-Resistant Staphylococcus aureus/genetics* ; Microbial Sensitivity Tests ; Multilocus Sequence Typing/methods* ; Phylogeny ; Staphylococcal Infections/epidemiology* ; Staphylococcus aureus/genetics*

Moslae Herba is a commonly used aromatic Chinese medicinal with volatile oil as the main effective component and exhibits broad-spectrum antibacterial and antiviral effects. However, the irritation and instability of Moslae Herba volatile oil necessitate the preparation into a specific dosage form. In this study, the steam distillation method was employed to extract the Moslae Herba volatile oil. The content of thymol and carvacrol in Moslae Herba volatile oil was determined by HPLC as(0.111 9±0.001 0) and(0.235 4±0.004 7) mg·mL~(-1), respectively. Pseudo-ternary phase diagrams and surfactants compounding were applied in the selection of the optimal excipients(surfactant and cosurfactant). On this basis, a nanoemulsion was prepared from the Moslae Herba volatile oil and then loaded into pressure vessels to get sprays, whose stability and antibacterial activity were evaluated afterward. With clarity, viscosity, smell and body feeling as comprehensive indexes, the optimal formulation of the Moslae Herba volatile oil nanoemulsion was determined as follows: Moslae Herba volatile oil∶peppermint oil∶cremophor EL∶absolute ethanol∶distilled water 7.78∶1.58∶19.26∶6.15∶65.23. The as-prepared nanoemulsion was a light yellow transparent liquid, with Tyndall effect shown under the irradiation of parallel light. It has the pH of 5.50, conductivity of 125.9 μS·cm~(-1), average particle size of 15.45 nm, polydispersity index(PDI) of 0.156, and Zeta potential of-17.9 mV. Under a transmission electron microscope, the Moslae Herba volatile oil nanoemulsion was presented as regular spheres without adhesion and agglomeration. Stability test revealed that the Moslae Herba volatile oil nanoemulsion was stable at 4-55 ℃, which was free from demulsification and stratification within 30 days. After the centrifugation at 12 000 r·min~(-1) for 30 min, there was no stratification either. The nanoemulsion had good inhibitory effects on Escherichia coli, Staphylococcus aureus and resistant S. aureus strains, with the minimum inhibitory concentrations of 0.39, 3.12 and 1.56 mg·mL~(-1), respectively. The above results demonstrated that the nanoemulsion was prepared feasibly and showed stable physical and chemical properties and good antibacterial effects. This study provides a practicable technical solution for the development of anti-epidemic and anti-infection products from Moslae Herba volatile oil.
Anti-Bacterial Agents/pharmacology* ; Emulsions ; Methicillin-Resistant Staphylococcus aureus ; Microbial Sensitivity Tests ; Oils, Volatile ; Particle Size

A new isobenzoisofuran(1) has been isolated from the whole plant of Cassia pumila using various chromatographic techniques, including silica gel, Sephadex, MCI-gel resin, and RP-HPLC, and its structure was determined as 9-(2-hydroxyethyl)-2,2-dimethyl-2H-furo[3,4-g]chromen-6(8H)-one. This compound was also evaluated for its antibacterial activity. The results showed that it had prominent antibacterial activity with MIC_(90) value of(45.2±4.2) μg·mL~(-1) for methicillin resistant Staphylococcus aureus(MRSA) strain. This value was closed to that of levofloxacin [with MIC_(90) value(48.5±4.3) μg·mL~(-1)].
Anti-Bacterial Agents/pharmacology* ; Benzofurans/pharmacology* ; Cassia/chemistry* ; Levofloxacin ; Methicillin-Resistant Staphylococcus aureus/drug effects* ; Microbial Sensitivity Tests ; Phytochemicals/pharmacology* ; Plants, Medicinal/chemistry*

A new isobenzofuranone derivative was isolated from Chaenomeles sinensis by using various chromatographic techniques,including silica gel,Sephadex LH-20,MCI-gel resin and RP-HPLC. This compound was determined as 2,2-dimethyl-5-( 2-oxopropyl)-2 H-furo[3,4-h]chromen-7( 9 H)-one( 1) by NMR,MS,IR and UV spectra,and was also evaluated for its antibacterial activity. The results showed that it showed prominent antibacterial activity with MIC90 value of( 53. 7±4. 5) mg·L-1 for methicillin resistant Staphylococcus aureus( MRSA) strain. This value is close to that of levofloxacin [with MIC90 value( 50. 2± 4. 2) mg·L-1].
Anti-Bacterial Agents ; isolation & purification ; pharmacology ; Benzofurans ; isolation & purification ; pharmacology ; Chromatography, High Pressure Liquid ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; Microbial Sensitivity Tests ; Phytochemicals ; isolation & purification ; pharmacology ; Rosaceae ; chemistry

OBJECTIVEThis study examined the antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus (MRSA) and used a standardized purification protocol to determine the presence and abundance of bioactive compounds in the leaf extracts.

METHODSIn vitro antimicrobial activities of the ethanolic extracts of C. sativa, T. orientalis and P. guajava were tested against MRSA. The presence of bioactive molecules in these three leaves was evaluated using biochemical assays and high-performance thin-layer chromatography (HPTLC).

RESULTSResistance to methicillin, penicillin, oxacillin and cefoxitin was observed in each of the clinical and nonclinical MRSA isolates. However, they were still vulnerable to vancomycin. Used individually, the 50% extract of each plant leaf inhibited MRSA growth. A profound synergism was observed when C. sativa was used in combination with T. orientalis (1:1) and when P. guajava was used in combination with T. orientalis (1:1). This was shown by larger zones of inhibition. This synergism was probably due to the combined inhibitory effect of phenolics present in the leaf extracts (i.e., quercetin and gallic acid) and catechin, as detected by HPTLC.

CONCLUSIONThe leaf extracts of C. sativa, T. orientalis and P. guajava had potential for the control of both hospital- and community-acquired MRSA. Moreover, the inhibitory effect was enhanced when extracts were used in combination.

Anti-Bacterial Agents ; pharmacology ; Cannabis ; Drug Resistance ; drug effects ; Humans ; Methicillin ; pharmacology ; Methicillin-Resistant Staphylococcus aureus ; drug effects ; growth & development ; Microbial Sensitivity Tests ; Phytotherapy ; Plant Extracts ; pharmacology ; Plant Leaves ; Psidium ; Staphylococcal Infections ; drug therapy ; microbiology ; Thuja