| Multidrug-resistant bacteria(MDR)infection has become one of the most troublesome problems for global doctors.Currently,the main way to treat multidrug-resistant bacteria is to select antibiotics that are sensitive to multidrug-resistant bacteria through drug sensitivity test.However,the possibility of bacterial resistance to the antibiotics still exists even choosing the sensitive antibiotics to a certain multidrug resistant bacteria.Once the resistant bacteria is resistant to the originally sensitive antibiotics,it will be very difficult for further clinical treatment,and the patient's prognosis will be very poor.Therefore,it is of great significance to develop drugs to inhibit multidrug-resistant bacteria and to enhance the sensitivity of antimicrobial agents.Qingying Decoction is one of the representative prescriptions of treating febrile diseases.It has the effect of clearing away heat and toxic material.The Qingying Decoction is made up of 9 kinds of Chinese medicine monomers.Many of the monomers and the effective components of these monomers have inhibitory effects on multidrug-resistant bacterias.Modern research indicates that the Qingying Decoction has the effect of treating infectious diseases,and some of the infectious diseases are caused by multidrug-resistant bacterias.This study explored the bacteriostasis of Qingying Decoction on multidrug-resistant bacteria,as well as the sensitization effect of the combination of Qingying Decoction and antibiotics.Objective: The purpose of this study is to study the bacteriostasis of Qingying Decoction on MRSA and its sensitizing effect on antibiotics when combined with antibiotics.Therefore it can provide experimental basis for the clinical usage of Qingying Decoction and its combination with antibiotics to treate the infections caused by MRSA.Methods: In this experiment,the K-B paper method is used to detect the size of bacteriostasis rings of common antibiotics acting on MRSA.Therefore,the drug resistance spectrum of MRSA is determined;The minimum inhibitory concentration of Qingying Decoction on MRSA is measured by microdilution method;K-B paper method is used to compare the bacteriostatic effect of Qingying Decoction in low,middle and high concentration groups and to detect whether the different concentrations of Qingying Decoction combined with antibiotics could enhance the sensitivity of the antibiotics.Results:(1)The 20 clinical isolates of MRSA were consistent with the standard identification of MRSA and they were all multidrug-resistant;(2)Qingying Decoction had a certain inhibitory effect on MRSA,the minimum inhibitory concentration ranged from 250mg/mL to 500mg/mL;(3)The inhibitory effect of high dose(2g/mL)Qingying Decoction group on MRSA was significantly higher than that of the low dose(0.5g/mL)one(P<0.01),the inhibitory effect of middle dose(1g/mL)Qingying Decoction group on MRSA is significantly higher than that of the low dose(0.5g/mL)one(P<0.01),the inhibitory effect of high dose(2g/mL)Qingying Decoction group on MRSA is significantly higher than that of the middle dose(1.0g/mL)one(P<0.01);(4)There were no sensitizing effects of 12 commonly used antibiotics in combination with different concentrations of Qingying Decoction(P>0.05).The two antibiotics,nitrofurantoin and levofloxacin,had sensitizing effects when respectively combined with Qingying Decoction(P<0.05).The antibacterial effects of 0.25g/mL,0.5g/mL,1g/mL Qingying Decoctions respectively combined with nitrofurantoin were all better than those of nitrofurantoin alone(P<0.05),and with the concentration of Qingying Decoction increasing,the antibacterial effect became stronger(P<0.05).As for levofloxacin,The antibacterial effects of 0.5g/mL and 1g/mL Qingying Decoction respectively combined with levofloxacin were both more effective than that of levofloxacin alone(P<0.05),while the two groups had the same sensitizing effects on levofloxacin(P>0.05).Conclusion: The clinical isolates of 20 strains of MRSA were all multidrug-resistant MRSA strains;The Qingying Decoction had certain inhibitory effect on MRSA,and its minimum inhibitory concentration was(250mg/mL-500mg/mL),but the MIC value was relatively high;The bacteriostasis effect of high dose(2.0g/mL)Qingying Decoction acting on MRSA was better than that of the middle dose(1.0g/mL)one,and the bacteriostasis effect of middle dose(1.0g/mL)Qingying Decoction acting on MRSA was stronger than that of the low dose(0.5g/mL)one.With the increase of the concentration of Qingying Decoction,the bacteriostasis effect got enhanced;0.25g/mL,0.5g/mL,1g/mL Qingying Decoctions respectively combined with nitrofurantoin had sensitizing effects,and with the increase of the concentration of Qingying Decoction,the sensitizing effect was enhanced;0.5g/mL,1g/mL Qingying Decoctions respectively combined with levofloxacin had the sensitization effect,and the sensitization effect of them were the same;The different concentration gradients Qingying Decoctions respectively combined with 12 other commonly used antibiotics were with no sensitizing effect. |
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