金黄色葡萄球菌肠毒素的检测和耐药性分析

目的了解临床分离的金黄色葡萄球菌(SA)产肠毒素(SE)的情况及耐药现状。方法对从临床标本中分离出的260株SA,用反向间接血凝试验检测其肠毒素,按2005年美国临床实验室标准化委员会(NCCLS)的标准,用K-B法对260株SA进行药物敏感性试验,耐甲氧西林金黄色葡萄球菌(MRSA)检测分别用检测头孢西丁及乳胶凝集检测PBP2a方法进行。结果260株SA中有172株携带肠毒素,占66.2%,主要为SEA型10.8%(28/260)、SEB型14.6%(38/260)、SEC型10.0%(26/260),同时携带二种或二种以上肠毒素的占23.8%(62/260);其中MRSA134株,全部携带肠毒素,且以SEA、SEB和SEC为主,分别为19.4%、16.4%和13.4%;甲氧西林敏感金黄色葡萄球菌(MSSA)126株,携带肠毒素率为30.0%(38/126),以SEB为主,占9.5%。用头孢西丁及检测PBP2a的方法检测MRSA,检出率无显著意义(P>0.05);SA对临床常用的抗菌素除万古霉素及替考拉宁较敏感(100.0%敏感),其它的抗菌素存在多重耐药性,且MRSA的耐药性比MSSA的强。结论临床分离的SA株大部分都携带肠毒素,MRSA的带毒率及耐药性均高于MSSA;临床应重视SA肠毒素和MRSA的检测,合理使用抗菌素。

Detection of Enterotoxin and Analysis of the Drug-resistant Staphylococcus aureus

Objective To analyze the occurrence of enteroteoxin-producing strains and drug-resistant Staphylococcus aureus(SA)isolated from clinical samples. Methods Rreverse passive hemagglutination(RPHA) method was used in the determination of enterotoxin. Analysis was performed according to the methods recommended by NCCLS.K-B method was used to test for the antibiotics sensitivity of the bacterial isolates.Methicillin-resistant Staphylococcus aureus(MRSA)was identified using latex fixation test and FOX test. Results 66.2%(172/260)of Staphylococcus aureus isolates were enterotoxin-producing strains SEA 10.8% (28/260); SEB 14.6% (38/260);and SEC 10.0%(26/260). 23.8%(62/260)of the isolates produced two or more than two types of enterotoxins.All 134 MRSA isolates produced enterotoxin (SEA 19.4%,SEB 16.4%, and SEC 13.4%). Among the 126 MSSA isolates, 38 strains were enterotoxin-producing strains. There was no significant difference in the identification rate between the FOX and PBP2a method (P>0.05). Most of the Staphylococcus aureus isolates were sensitive to vancomycin and Teicoplanin. The antibiotic-resistance of MRSA was higher than MSSA.Conclusion Most of the clinical isolates of Staphylococcus aureus are enterotoxin-producing strains. The frequency of enterotoxin-producing and antibiotic-resistance of MRSA strains was higher than MSSA.Effort should be made on the detection of enterotoxin-producing Staphylococcus aureus and MRSA. Antibiotics should also be used with caution.