目的 检测多重耐药伤寒沙门菌对抗菌药物的敏感性及其耐药基因定位。方法 随机选取实验室保存的5株耐药菌和1株敏感菌，用纸片扩散法检测对12种抗菌药物的敏感性。用利舍平抑制试验检测菌株是否存在药物外排系统。PCR法检测TEM型β-内酰胺酶基因、aac(6′)-Ⅰb和aac3-Ⅱ型氨基糖苷类修饰酶基因、qacEΔ1-sul1耐消毒剂和磺胺基因、catA和catB氯霉素乙酰基转移酶基因以及cmlA氯霉素外排泵蛋白基因等7种耐药基因。结果 5株多重耐药菌对氨苄西林、哌拉西林、头孢呋辛、头孢西丁、卡那霉素、庆大霉素、复方磺胺甲噁唑及氯霉素等8种抗菌药物全部耐药，对美罗培南、头孢哌酮、头孢吡肟全部敏感；对头孢噻吩中度敏感。1株无质粒pRST98的菌株对上述药物全部敏感。利舍平抑制试验均为阴性。4株耐药菌TEM型β-内酰胺酶基因检测为阳性。全部耐药菌株aac3-Ⅱ、qacEΔ1-sul1、catA基因均为阳性，而aac(6′)-Ⅰb、catB和cmlA基因均为阴性。 结论 多重耐药伤寒沙门菌质粒pRST98上同时存在多种耐药基因, 是导致菌株同时对多种结构各异的抗生素耐药的原因。

Objective To identify the antibiotic sensitivity of multi-drug resistant Salmonella typhi and detect its resistant genes. Methods 5 resistant Salmonella typhi strains and 1 sensitive strain was selected randomly, then antibiotic susceptibility to 12 different antibiotics were tested by K-B method. Reserpine inhibition test was also performed to find the drug excretion system. TEM type of β-lactamase gene, aminoglycosides modifying enzyme gene aac(6′)-Ⅰb, aac3-Ⅱ, qacEΔ1-sul1 gene, catA, catB gene, and cmlA gene were detected by PCR process. Results 5 multi-drug resistant strains were resistant to ampicillin, piperacillin, cefuroxime, ceftazidime, kanamycin, gentamycin, trimesulf and chloramphenicol, and they were all sensitive to meropenem, cefoperazone and cefepime; they showed an intermediate sensitivity to cafalotin. The strain which doesn’t carry pRST98 was sensitive to all of the antibiotics. All strains were negative in reserpine inhibition test. 5 drug-resistant strains carried aac3-Ⅱ、qacEΔ1-sul1 and catA gene, 4 of them harbored TEM type of β-lactamase gene, but none of the 5 strains carried aac(6′)-Ⅰb, catB or cmlA. Conclusion The multi-drug resistant Salmonella typhi strains carrying pRST98 contained an array of drug resistant genes, which lead to the resistance to different antibiotics.