伤寒沙门氏菌耐药性与外膜蛋白关系的研究

对临床分离的２６株伤寒沙门氏菌进行了外膜蛋白，质粒，药物敏感试验及氯霉素乙酰基转移酶（ＣＡＴ）活性测定。结果显示：２６株菌中有８株耐氯霉素，其中７株对氯霉素等４种抗生素高度耐药（ＭＩＣ＞２００μｇ／ｍｌ），均含９８．６Ｍｄ大质粒，１株对氯霉素敏感而耐氨苄青霉素的菌株亦含该质粒。８株菌除１株外其氯霉素乙酰转移酶活性均为阳性。外膜蛋白指纹图谱示伤寒沙门氏菌均含５２、３８、３７、３６ＫＤ主蛋白，其中有３株耐药菌３７ＫＤ蛋白含量减少或缺失，实验表明伤寒沙门氏菌耐药性与质粒相关，ＣＡＴ由质粒调控，个别菌株存在非酶性耐药，可能与外膜蛋白的减少或缺失有关。

STUDY ON THE RELATION BEWEEN THE BACTERIAL DRUG RESISTANCE ANG OUTER MEMBRANE PROTEINS IN SALMONELLA TYPHI

In order to know the relation beweent the resistance to antibiotics and Outer me- mbrane proteins, 26 clinical isolates of S. typhi were studied. Antibiotic susceptibility test, CAT activity assay. Plasmid DNA examination and outer membrane protein pro- file analysis were done. Results showed that 7 of 8 multiple resistant S. typhi were highly resistant to chloromycetin(MIC 200ug/ml) and possessed a 98.6Md plasmid,while only one strain of chloromycetin. sensitive S. typhi(CSST) possessed the same plasmid.Seven chloromycetin resistant S. typhi(CRST) had detectable CAT activity while one CRST had none.52,38,37 and 36 KD were the major outer membrane protein of S.typhi in three highly CRST.The 37KD protein content,Which may serve as Pori for the entry of chloromycetin and other hydrophilic antibiotics,was diminished or absent.The bacterial resistantce in most strains of S. typhi is mediated by plasmid,but in some strains alteration of outer membrane proteins may also be involed in the mechanism of resistance to antibiotics.