Feng P, Yu R, Xia P, Lü X, Zhu S
Department of Infectious Diseases, First Affiliated Hospital, WCUMS, Chengdu 610041, China.
Hua Xi Yi Ke Da Xue Xue Bao. 2001 Dec;32(4):501-4.
To investigate the factors of quinolone-resistance mediating in Escherichia coli(E. coli), Staphylococcus aureus (S. aureus) and Pseudomonas areuginosa(P. areuginosa) and examine the characteristic changes and quinolones resistance of these bacteria after exposing them to quinolones, dye-materials, and ultraviolet respectively.
The agar plate inoculating on surface and tube broth two-fold dilution methods were adopted.
Quinolone-resistance was mainly mediated by repeated exposure of the bacteria to low level concentration of quinolone. No quinolone-resistance was found after exposure of the bacteria to ultra-violet and dye materials such as Ethidium bromide and Acry-orange. Among the three kinds of bacteria, E. coli tended to have stable high level of quinolone- resistance(MICs > or = 256 mg/L). S. aureus acquired mediate level of quinolone-resistance(MICs < or = 32 mg/L). P. aeruginosa acquired a high but not stable level(MICs > or = 256 mg/L) of resistance. These bacteria were cultured in the concentration of 1/2 x MIC, 1 x MIC, 2 x MIC, 4 x MIC, 5 x MIC ciprofloxacin, and were compared with those cultured in the same concentration of sparfloxacin and cefotaxime. After being affected by ciprofloxacin, the E. coli underwent apparent morphologic changes, such as becoming wider(2-3 times), longer(10-30 times), thread-like, and fewer in number. These changes were consistent with the increase of quinolone concentrations. The morphologic changes in P. aeruginosa and S. aureus were not so obvious as those in E. coli. Sparfloxacin and cefotaxime mainly led to the decrease in the numbers of bacteria. When the concentration of Sparfloxacin and cefotaxime were 4 x MICs, the changes of P. aeruginosa and S. aureus were less obvious.
The bacteria's quinolone-resistance is mainly induced by the quinolone itself. The quinolone-resistance is more likely occur in E. coli than in P. aeruginosa and S. aureus. After exposure of the bacteria to ciprofloxacin, E. coli might have most apparent morphologic changes and occurrence resistance.
研究大肠杆菌、金黄色葡萄球菌和铜绿假单胞菌中喹诺酮耐药的介导因素，并分别观察这些细菌在暴露于喹诺酮类、染料物质和紫外线后其特性变化及喹诺酮耐药情况。
采用平板表面接种法和试管肉汤二倍稀释法。
喹诺酮耐药主要是由细菌反复暴露于低水平浓度的喹诺酮介导的。细菌在暴露于紫外线及溴化乙锭、吖啶橙等染料物质后未发现喹诺酮耐药。在这三种细菌中，大肠杆菌倾向于具有稳定的高水平喹诺酮耐药（最低抑菌浓度[MIC]≥256mg/L）。金黄色葡萄球菌获得中等水平的喹诺酮耐药（MIC≤32mg/L）。铜绿假单胞菌获得高但不稳定水平（MIC≥256mg/L）的耐药。将这些细菌分别在1/2×MIC、1×MIC、2×MIC、4×MIC、5×MIC浓度的环丙沙星中培养，并与在相同浓度的司帕沙星和头孢噻肟中培养的细菌进行比较。受环丙沙星作用后，大肠杆菌出现明显的形态学变化，如变宽（2 - 3倍）、变长（10 - 30倍）、呈丝状且数量减少。这些变化与喹诺酮浓度的增加一致。铜绿假单胞菌和金黄色葡萄球菌的形态学变化不如大肠杆菌明显。司帕沙星和头孢噻肟主要导致细菌数量减少。当司帕沙星和头孢噻肟的浓度为4×MIC时，铜绿假单胞菌和金黄色葡萄球菌的变化较不明显。
细菌的喹诺酮耐药主要由喹诺酮本身诱导。大肠杆菌比铜绿假单胞菌和金黄色葡萄球菌更易发生喹诺酮耐药。细菌在暴露于环丙沙星后，大肠杆菌可能具有最明显的形态学变化及耐药发生。
