新疆南疆地区表皮葡萄球菌对氟苯尼考注射液的药物敏感性研究

Study on antimicrobial susceptibility of Staphylococcus epidermidis to florfenicol injection in southern Xinjiang Uygur Autonomous Region

为了探索新疆南疆地区表皮葡萄球菌对氟苯尼考注射液的敏感性,试验采用微量肉汤稀释法测定了氟苯尼考注射液对表皮葡萄球菌ATCC 35984和临床分离株的最低抑菌浓度(MIC)、最低杀菌浓度(MBC),对表皮葡萄球菌生长、生物被膜形成的抑制作用及表面疏水性的影响,测定了氟苯尼考注射液的体外抑菌效果及其对表皮葡萄球菌细胞膜完整性的影响。结果表明:氟苯尼考注射液对表皮葡萄球菌ATCC 35984和临床分离株的MIC值分别为4,2μg/mL,MBC值分别为16,8μg/mL。与未加氟苯尼考注射液的菌液相比,0.5μg/mL氟苯尼考注射液可显著抑制表皮葡萄球菌生长,0.25μg/mL氟苯尼考可显著抑制其生物被膜的形成(P<0.05),浓度>2μg/mL时抑制效果极显著(P<0.01),呈浓度依赖性;氟苯尼考注射液可降低表皮葡萄球菌细胞表面疏水性,呈浓度依赖性。当氟苯尼考注射液浓度为1/2 MIC时,可在体外显著抑制表皮葡萄球菌ATCC 35984生长(P<0.05);当浓度高于1 MIC时,可极显著抑制表皮葡萄球菌ATCC 35984和临床分离株生长(P<0.01)。当氟苯尼考注射液浓度>1/2 MIC时,其可损伤表皮葡萄球菌的细胞膜完整性。说明新疆南疆地区表皮葡萄球菌对氟苯尼考注射液的药物敏感性较好,氟苯尼考可能是通过降低表皮葡萄球菌细胞表面疏水性和损伤表皮葡萄球菌的细胞膜完整性来发挥抑菌和杀菌作用的。

In order to explore the antimicrobial susceptibility of Staphylococcus epidermidis to florfenicol injection in southern Xinjiang Uygur Autonomous Region,in this experiment,microbroth dilution method was used to determine the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of florfenicol injection against Staphylococcus epidermis ATCC 35984 and clinical isolates;the effect on the growth of Staphylococcus epidermidis and the formation of biofilm and surface hydrophobicity were determined;the antibacterial effect of florfenicol injection in vitro and its effect on the integrity of the cell membrane of Staphylococcus epidermidis were determined.The results showed that the MIC values of florfenicol injection for Staphylococcus epidermis ATCC 35984 and clinical isolates were 4 and 2μg/mL,respectively,and MBC values of them were 16 and 8μg/mL,respectively.Compared with the bacterial solution without florfenicol injection,0.5μg/mL florfenicol injection could significantly inhibit the growth of Staphylococcus epidermidis and 0.25μg/mL florfenicol injection could significantly inhibit the formation of its biofilm(P<0.05).When the concentration was higher than 2μg/mL,the inhibition effect was very significant(P<0.01),which was concentration-dependent.Florfenicol injection could reduce the surface hydrophobicity of Staphylococcus epidermidis and was concentration-dependent.When the concentration of florfenicol injection was 1/2 MIC,it significantly inhibited the growth of Staphylococcus epidermidis ATCC 35984(P<0.05),when the concentration was higher than 1 MIC,the growth of Staphylococcus epidermidis ATCC 35984 and clinical isolates could be significantly inhibited in vitro(P<0.01).Florfenicol injection could impair the cell membrane integrity of Staphylococcus epidermidis.The results suggested that Staphylococcus epidermidis in southern Xinjiang Uygur Autonomous Region had good drug sensitivity to florfenicol injection,and florfenicol might play bacteriostatic and bactericidal effects by reducing the hydrophobicity on the cell surface of Staphylococcus epidermidis and damaging the cell membrane integrity of Staphylococcus epidermidis.