Identification of novel antimicrobial resistance genes from microbiota on retail spinach
Identification of novel antimicrobial resistance genes from microbiota on retail spinach
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DOI：
10.1186/1471-2180-13-272
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发表时间：
2013-12-01
期刊：
影响因子：
4.2
通讯作者：
Riley, Lee W.
中科院分区：
文献类型：
--
作者：
Berman, Hillary F.;Riley, Lee W.
背景：耐药基因及其可移动遗传元件经常从环境腐生生物中鉴定出来。人们普遍认为，畜牧业中抗生素的使用会选择耐药微生物，然后通过食用受污染的食品从农场环境传播到人类。我们希望从零售食品的微生物群落中鉴定出新型耐药基因。在这里，我们选择研究零售菠菜的微生物群落，因为它通常是生吃的，并且以前曾与细菌感染的爆发有关。结果：我们从零售菠菜样品中分离的微生物群创建了宏基因组质粒文库。我们鉴定了五种独特的质粒，它们增加了大肠杆菌宿主对抗菌药物的耐药性。这些质粒在含有氨苄青霉素 (pAMP)、氨曲南 (pAZT)、环丙沙星 (pCIP)、甲氧苄啶 (pTRM) 和甲氧苄啶-磺胺甲恶唑 (pSXT) 的平板上生长的大肠杆菌中得到鉴定。我们在所有 5 个质粒的 DNA 插入片段中鉴定出与已知类别的耐药基因相似的开放阅读框。这些耐药基因赋予对氟喹诺酮类、头孢菌素和甲氧苄啶的耐药性，这些抗菌药物经常用于治疗人类革兰氏阴性细菌感染。这些结果表明，在零售产品的微生物群中发现了新的耐药基因。结论：在这里，我们表明零售菠菜的微生物群包含以前未被识别为具有抗生素耐药性的 DNA 序列。这些新序列中有许多与细菌物种中发现的基因相似，这些细菌先前已被鉴定为植物上发现的共生细菌或腐生细菌。我们证明这些耐药基因能够赋予临床相关水平的抗菌药物耐药性。食物腐生菌可能是人类病原体中新的耐药决定因素的重要储存库。
Background: Drug resistance genes and their mobile genetic elements are frequently identified from environmental saprophytic organisms. It is widely accepted that the use of antibiotics in animal husbandry selects for drug resistant microorganisms, which are then spread from the farm environment to humans through the consumption of contaminated food products. We wished to identify novel drug resistance genes from microbial communities on retail food products. Here, we chose to study the microbial communities on retail spinach because it is commonly eaten raw and has previously been associated with outbreaks of bacterial infections.Results: We created metagenomic plasmid libraries from microbiota isolated from retail spinach samples. We identified five unique plasmids that increased resistance to antimicrobial drugs in the E. coli host. These plasmids were identified in E. coli that grew on plates that contained ampicillin (pAMP), aztreonam (pAZT), ciprofloxacin (pCIP), trimethoprim (pTRM), and trimethoprim-sulfamethoxazole (pSXT). We identified open reading frames with similarity to known classes of drug resistance genes in the DNA inserts of all 5 plasmids. These drug resistance genes conferred resistance to fluoroquinolones, cephalosporins, and trimethoprim, which are classes of antimicrobial drugs frequently used to treat human Gram negative bacterial infections. These results show that novel drug resistance genes are found in microbiota on retail produce items.Conclusions: Here we show that microbiota of retail spinach contains DNA sequences previously unidentified as conferring antibiotic resistance. Many of these novel sequences show similarity to genes found in species of bacteria, which have previously been identified as commensal or saprophytic bacteria found on plants. We showed that these resistance genes are capable of conferring clinically relevant levels of resistance to antimicrobial agents. Food saprophytes may serve as an important reservoir for new drug-resistance determinants in human pathogens.