Comparative analysis of genetic diversity and incidence of virulence factors and antibiotic resistance among enterococcal populations from raw fruit and vegetable foods, water and soil, and clinical samples
Comparative analysis of genetic diversity and incidence of virulence factors and antibiotic resistance among enterococcal populations from raw fruit and vegetable foods, water and soil, and clinical samples
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DOI：
10.1016/j.ijfoodmicro.2007.11.067
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发表时间：
2008-03-31
影响因子：
5.4
通讯作者：
Galvez, Antonio
中科院分区：
文献类型：
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作者：
Abriouel, Hikmate;Ben Omar, Nabil;Galvez, Antonio
对从果蔬食品、水和土壤中分离的肠球菌与临床标本进行了比较研究。结果表明，在不同环境中发现的隐球菌种的数量及其丰度存在很大差异。临床样品中明显以粪肠球菌为主，蔬菜中以粪肠球菌为主，水样中粪肠球菌略多于粪肠球菌。其他种类(希雷肠球菌、蒙氏肠球菌、杜氏肠球菌、鸡肠球菌和干酪肠球菌)在蔬菜、水中，特别是在土壤中出现的频率更高。与临床分离株相比，蔬菜类食品分离株对大多数抗菌药物的耐药率较低，尤其是对粪肠球菌的红霉素、四环素、氯霉素、环丙沙星、左氧氟沙星、庆大霉素和链霉素；对粪肠球菌的喹普汀/达福平、氨苄西林、青霉素、环丙沙星、左氧氟沙星、利福平、氯霉素、庆大霉素和呋喃妥因的耐药率较低。从蔬菜、食品和水中分离的粪肠球菌对抗生素的抗性性状(蔬菜和水分离株分别为2.95和3.09个性状)平均低于临床样本(7.5个性状)。多重耐药株在粪肠球菌临床分离株中也较常见(平均为5.46个性状)。从蔬菜食品、水和土壤中分离的粪肠球菌和粪肠球菌均未表现出β溶血活性，而临床分离的粪肠球菌有25.64%表现出溶血活性。粪肠球菌临床分离株中有51.28%的菌株的cyA、cylB、cylM基因检测为阳性，其余菌株部分或全部缺失。在粪肠球菌和粪肠球菌临床分离株中，肠球菌表面蛋白基因(Esp)、胶原粘附素基因(Ace)和性信息素基因ccf(以及粪肠球菌中的cob)的遗传决定基因的发生率明显高于其他来源的分离株。从蔬菜食品和水中分离的粪肠球菌平均每株毒力基因数(分别为4.23和4.0)远低于临床分离株(8.71)。同样，在粪肠球菌中，每个菌株的平均特征数最低的是蔬菜食品分离株(1.72)，其次是水分离株(3.9)和临床分离株(4.73)。ESPF-aceF-ccfF和ESPF-ccfF的长度异质性(LH)-PCR分型显示，临床分离株与植物食品、水和土壤分离株(除两株临床分离株外)有明显的差异。在抗生素耐药性和毒力因子的发生率以及通过黄体生成素-聚合酶链式反应确定的遗传指纹上发现的巨大差异表明，医院适应的肠球菌群体与开放环境中发现的肠球菌群体有明显的分离。(C)2007 Elsevier B.V.保留所有权利。
A comparative study was carried out among enterococci isolated from fruits and vegetable foods, water and soil, and clinical samples. Results indicate strong differences in the numbers of enfterococcal species found in different environments as well as their abundance. While Enterococcus faecalis was clearly the predominant species in clinical samples, Enterococcus faecium predominated in vegetables, and it slightly outnumbered E. faecalis in water samples. Other species (Enterococcus hirae, Enterococcus mundtii, Enterococcus durans, Enterococcus gallinarum and Enterococcus casseliflavus) were found more frequently in vegetables, water, and specially in soil. Isolates from vegetable foods showed a lower incidence of antibiotic resistance compared to clinical isolates for most antimicrobials tested, especially erythromycin, tetracycline, chloramphenicol, ciprofloxacin, levofloxacin, gentamicin and streptomycin for E. faecalis, and quinupristin/dalfopristin, ampicillin, penicillin, ciprofloxacin, levofloxacin, rifampicin, choramphenicol, gentamicin and nitrofurantoin for E. faechim. E. faecium isolates from vegetable foods and water showed an average lower number of antibiotic resistance traits (2.95 and 3.09 traits for vegetable and water isolates, respectively) compared to clinical samples (7.5 traits). Multi-resistant strains were also frequent among clinical E. faecalis isolates (5.46 traits on average). None of E. faecalis or E. faecium isolates from vegetable foods, water and soil showed beta-haemolytic activity, while 25.64% of clinical E. faecalis did. A 51.28% of E. faecalis clinical isolates tested positive for the cylA, cylB, cylM set of genes, while some or all of these genes were missing in the rest of isolates. In clinical E. faecalis and E. faecium isolates, the genetic determinants for the enterococcal surface protein gene (esp), the collagen adhesin gene (ace) and the sex pheromone gene ccf (as well as cob in E. faecalis) showed a clearly higher incidence compared to isolates from other sources. E. faecalis isolates from vegetable foods and water had much lower average numbers of virulence genetic determinants per strain (4.23 and 4.0, respectively) compared to clinical isolates (8.71). Similarly, among E. faecium the lowest average number of traits per strain occurred in vegetable food isolates (1.72) followed by water (3.9) and clinical isolates (4.73). Length heterogeneity (LH)-PCR typing with espF-aceF-ccfF and espF-ccfF primers revealed genomic groups that clearly differentiated clinical isolates from those of vegetable foods, water and soil (except for two clinical isolates). The large differences found in the incidence of antibiotic resistance and virulence factors and in the genetic fingerprints determined by LH-PCR suggest a clear separation of hospital-adapted populations of enterococci from those found in open environments. (C) 2007 Elsevier B.V. All rights reserved.