| 摘要: |
| 【目的】了解陕西关中地区猪肉中金黄色葡萄球菌（Staphylococcus aureus）的污染状况、耐药性及其毒素基因的分布。【方法】采集陕西关中6个地区的猪肉165份，按国标GB/T 4789.10-2010的方法，对其中的金黄色葡萄球菌进行分离，采用PCR方法对该菌进行确证并对其相关基因（如nuc、mecA、PVL、SEs和ETs）进行检测，最后采用琼脂稀释法检测金黄色葡萄球菌对11种抗菌药物的耐药性。另外，在BP平板中分别添加头孢西丁（4 μg/mL）和苯唑西林（4 μg/mL），分离耐甲氧西林金黄色葡萄球菌（MRSA）。【结果】165份样品的金黄色葡萄球菌污染率为33.33%(55/165)；从中分离出103株金黄色葡萄球菌，但未检测出MRSA，这些菌对甲氧苄啶的耐药性最强，耐药率为100%；其次对红霉素和四环素的耐药率较高，分别为57.28%和34.95%；对苯唑西林、庆大霉素、氯霉素、环丙沙星的耐药率分别为2.91%，10.68%，2.91%和3.88%；所有菌株对头孢西丁、头孢哌酮、万古霉素、阿米卡星均敏感，同时得到21种耐药谱，多重耐药率达20.39%。猪肉金黄色葡萄球菌中杀白细胞素基因（Panton-valentine leukocidin，PVL）的检出率为34.95%，肠毒素基因（SEs）中sej的检出率最高，为98.06%，然后依次为sea（50.49%）、see（34.95%）、sed（31.07%）、sec(13.59%)、seh(8.74%)、sei(8.74%)、seg(6.80%)和seb(1.94%)；同时得到71种毒素基因型，以sea+sej（11.65%）最为流行，分布地区不尽相同，其次为PVL+sea+see+sej（9.71%），耐红霉素的金黄色葡萄球菌含的毒素基因类型比较复杂，sej基因检出率高达98.68%。在BP平板中分别添加头孢西丁和苯唑西林，均未检测出MRSA。【结论】猪肉存在金黄色葡萄球菌的污染，其污染菌株存在多重耐药性并携带较多毒素基因，提示应加强猪肉金黄色葡萄球菌的监测。在BP平板中分别添加头孢西丁（4 μg/mL）和苯唑西林（4 μg/mL）筛选MRSA的方法不一定可靠，其可信度有待证明。 |
| 关键词: 猪肉 金黄色葡萄球菌 毒素基因 耐药性 |
| DOI： |
| 分类号: |
| 基金项目:长江学者讲座教授奖励计划项目(Z111020001)；西北农林科技大学博士科研启动费项目（01140407） |
|
| Characterization of toxin genes and antimicrobial resistance of Staphylococcus aureus isolated from pork |
|
|
| Abstract: |
| 【Objective】The aim of the study was to investigate contamination,toxin gene properties and antimicrobial profile of Staphylococcus aureus strains isolated from pork in Guanzhong region,Shaanxi province.【Method】A total of 165 pork samples from six regions in Shaanxi province were collected and screened for the presence of S.aureus and MRSA.S.aureus isolates were characterized using antimicrobial susceptibility and PCR.Toxin genes including PVL,SEs and ETs were detected as well.In addition,MRSA was isolated by BP plates with cefoxitin (4 μg/mL) and oxacillin (4 μg/mL),respectively.【Result】Of the 165 pork samples,33.33% were contaminated.103 S.aureus strains were isolated and MRSA was not detected.The observed resistance against erythromycin were highest (100%),followed by erythromycin (57.28%),tetracycline (34.95%),gentamicin (10.68%),ciprofloxacin (3.88%),oxacillin (2.91%) and chloramphenicol (2.91%).All isolates of S.aureus were susceptible to cefoxitin,cefoperazone,vancomycin and amikacin.Of the 103 strains of S.aureus,20.39% were multiresistant.The predominant toxin gene was sej(98.06%),followed by sea(50.49%),see and PVL (each 34.95%).68.93% isolates harbored one or more SE genes,and the predominant toxin gene pattern was sea+sej（11.65%）,followed by PVL+sea+see+sej（9.71%）.Resistance against erythromycin S.aureus isolates harboring sej was most frequently observed.Finally,MRSA was not detected by BP plates with both cefoxitin (4 μg/mL) and oxacillin (4 μg/mL).【Conclusion】Many S.aureus isolated from pork contained different multiple resistances and toxin genes,and we should strengthen the monitoring of S.aureus from pork.MRSA was not isolated from pork as we used BP plates with cefoxitin (4 μg/mL) and oxacillin (4 μg/mL).The credibility of this approach needed to be proved. |
| Key words: pork Staphylococcus aureus toxin genes antimicrobials resistance |
