Brady M S, Strobel R J, Katz S E
Rutgers University, Cook College, Department of Biochemistry and Microbiology, New Brunswick, NJ 08903.
J Assoc Off Anal Chem. 1988 Mar-Apr;71(2):295-8.
An analytical procedure, based on the concept that exposure of bacteria to antibiotics will result in the selection of a resistant population, was developed. Two strains of enteric bacteria, Escherichia coli CS-1 and Enterobacter cloacae B520, which are sensitive to a wide variety of antibiotics, were used as the test organisms. E. coli CS-1 were exposed to 1.00 micrograms antibiotic or antimicrobial/mL; E. cloacae B520 were exposed to 0.01, 0.10, 0.50, 1.00, and 5.00 micrograms/mL. Both organisms developed increased resistance to other antibiotics after exposure to chlortetracycline and oxytetracycline, as measured by the minimum inhibitory concentration (MIC). E. cloacae B520 showed increased resistance to ampicillin, oxytetracycline, and chloramphenicol after exposure to levels as low as 0.10 microgram/mL. Exposure to streptomycin, sulfamethazine, tylosin, bacitracin, flavomycin, virginiamycin, and monensin at levels of 1.00 microgram/mL did not increase the MIC. Exposure to 5.00 micrograms streptomycin, sulfamethazine, tylosin, and monensin/mL increased the MIC of E. cloacae to one of the antibiotic markers. These increased MICs exceeded the 95% confidence limits of the MIC values of the unexposed organisms.
基于细菌暴露于抗生素会导致耐药菌群体产生这一概念，开发了一种分析程序。选用了两种对多种抗生素敏感的肠道细菌菌株，即大肠杆菌CS - 1和阴沟肠杆菌B520作为测试生物。将大肠杆菌CS - 1暴露于1.00微克抗生素或抗菌剂/毫升；将阴沟肠杆菌B520暴露于0.01、0.10、0.50、1.00和5.00微克/毫升。通过最低抑菌浓度（MIC）测定，两种生物在暴露于金霉素和土霉素后，对其他抗生素的耐药性均有所增加。阴沟肠杆菌B520在暴露于低至0.10微克/毫升的浓度后，对氨苄青霉素、土霉素和氯霉素的耐药性增加。暴露于1.00微克/毫升的链霉素、磺胺二甲嘧啶、泰乐菌素、杆菌肽、黄霉素、维吉尼亚霉素和莫能菌素，并未增加MIC。暴露于5.00微克链霉素、磺胺二甲嘧啶、泰乐菌素和莫能菌素/毫升，使阴沟肠杆菌对其中一种抗生素标记物的MIC增加。这些增加的MIC超过了未暴露生物MIC值的95%置信限。
