Isolation and determination of four potential antimicrobial components from Pseudomonas aeruginosa extracts.

Background:Pseudomonas aeruginosa can cause disease and also can be isolated from the skin of healthy people. Additionally, it exhibits certain antimicrobial effects against other microorganisms.Methods: We collected 60 strains of P. aeruginosa and screened their antimicrobial effects against Staphylococcus aureus (ATCC 25923) using the filter paper-disk method, the cross-streaking method and the co-culture method and then evaluated the antimicrobial activity of the chloroform-isolated S. aureus extracts against methicillin-resistant S. aureus (MRSA, Gram-positive cocci), vancomycin intermediate-resistant S. aureus (VISA, Gram-positive cocci), Corynebacterium spp. (CS, Gram-positive bacilli), Acinetobacter baumannii (AB, Gram-negative bacilli), Moraxella catarrhalis (MC, Gram-negative diplococcus), Candida albicans (CA, fungi), Candida tropicalis (CT, fungi), Candida glabrata (CG, fungi) and Candida parapsilosis (CP, fungi). Results: The PA06 and PA46 strains have strong antimicrobial effects. High-performance liquid chromatography (HPLC) analysis revealed that the major components of PA06 and PA46 that exhibit antimicrobial activity are functionally similar to phenazine-1-carboxylic acid (PCA) and pyocyanin. Preparative HPLC was performed to separate and isolate the 4 major potential antimicrobial components: PA06ER10, PA06ER16, PA06ER23 and PA06ER31. Further, the molecular masses of PA06ER10 (260.1), PA06ER16 (274.1), PA06ER23 (286.1) and PA06ER31 (318.2) were determined by electrospray ionization (ESI) mass spectrometry. Conclusion:P. aeruginosa can produce small molecules with potential antimicrobial activities against MRSA, VISA, CS, MC, CA, CT, CG and CP but not against AB.

The impact of mgrA on progression of Staphylococcus aureus sepsis.

Sepsis induced by Staphylococcus aureus has worse outcome with the appearance of methicillin-resistant Staphylococcus aureus (MRSA) because of multi-resistance to a large group of antibiotics, which may lead to death from septic shock. Pathogenesis of S. aureus infections are involved in the production of a wide variety of virulence factors. MgrA, a noval global regulator, is a member of the MarR (multiple antibiotic resistance regulator)/SarA (staphylococcal accessory regulator A) family proteins, which plays a key role in regulating the expression of major virulence factors in S. aureus. In the present study, by using a murine model of sepsis, we investigated the role of mgrA in onset and progression of S. aureus induced sepsis. We found that mice inoculated with wild-type strain Newman had significantly higher mortality (p = 0.029), more weight lost, more bacterial load in blood, spleen and kidney, more intense inflammation response, and worse histopathology than mice inoculated with mgrA knockout strain. Our results has provided evidence that mgrA is a global regulator in S. aureus, and play an important role in S. aureus sepsis, could increase mortality and accelerate the onset and development of sepsis.

An analysis of the correlation between the human apolipoprotein E gene polymorphism and lipoprotein-associated phospholipase A2.

BACKGROUND: Atherosclerosis is one of the most common cardiovascular and cerebrovascular diseases. This study aimed to explore the correlation between gene polymorphism of human apolipoprotein E (ApoE) and lipoprotein-associated phospholipase A2 (Lp-PLA2). METHODS: A total of 220 patients with atherosclerotic cardiovascular disease who were treated in our hospital from June 2016 to March 2017 were enrolled in this study and assigned as the atherosclerotic cardiovascular disease group and 193 patients who were treated contemporaneously in our hospital but had no atherosclerotic cardiovascular disease were enrolled and assigned as the control group. Gene polymorphism of ApoE was detected by PCR-fluorescent probe technique and the level of Lp-PLA2 was detected by ELISA. RESULTS: There were a total of 5 genotypes of ApoE in these two groups, which were E2/3, E3/3, E3/4, E2/4, and E4/4. E2/2 was not found in any of the patients. E3/3 made up the majority in both groups. There was no significant difference between the proportion of genotypes and frequencies of alleles in the two groups (P>0.05). There was no difference between LP-PLA2 among the different genotypes in these two groups (P>0.05). CONCLUSIONS: We cannot conclude that ApoE gene polymorphism is related to atherosclerotic cardiovascular and cerebrovascular diseases. And it cannot be concluded that ApoE gene polymorphism is related to Lp-PLA2 level.

[Association of polymorphism on HLA-DRB1*04 alleles with outcome of hepatitis B virus infection].

OBJECTIVE: To investigate the relation between the alleles of HLA-DRB1*04 and outcome of HBV infection. METHODS: The alleles of HLA-DRB1*04 were detected by polymerase chain reaction-sequence specific primer (PCR-SSP). The frequency of allele of HLA-DRB1*04 in four groups[106 asymptomatic HBsAg carriers (group ASC), 93 chronic hepatitis B patients (group CHB), 77 patients with hepatitis B cirrhosis and 102 cases of spontaneous recovery after HBV infection (control group)] were studied, and the frequency of that in different replication of HBV was also studied. RESULTS: The frequency of allele of HLA-RB1*04 in groups ASC, CHB and hepatitis B cirrhosis was markedly higher than that of control group (25.94%, 26.34%, 27.92% respectively versus 14.22%, P< 0.01); the frequency of HLA-DRB1*0401 in groups ASC, CHB and hepatitis B cirrhosis was also higher than that of control group (20.91%, 24.49%, 22.09% respectively versus 8.62%, P< 0.05, P< 0.01,P< 0.05 respectively); the frequency of HLA-DRB1*0405 in groups ASC, CHB and hepatitis B cirrhosis was lower than that of control group (3.64%, 2.04%, 3.49% respectively versus 15.52%, P< 0.01, P< 0.01, P< 0.05 respectively ). There was no statistical significance in the allele frequency of HLA-DRB1*04 among groups ASC, CHB and hepatitis B cirrhosis (P> 0.05), and the same result was observed in different replication of HBV (P> 0.05). CONCLUSION: HLA-DRB1*04 gene is one of the factors which determine the outcomes of HBV infection, while it has no influence on HBV replication.