Gaglio Raimondo, Couto Natacha, Marques Cátia, de Fatima Silva Lopes Maria, Moschetti Giancarlo, Pomba Constança, Settanni Luca
Dipartimento Scienze Agrarie e Forestali, Università di Palermo, Viale delle Scienze 4, 90128 Palermo, Italy; Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
Laboratory of Antimicrobial and Biocide Resistance, Faculty of Veterinary Medicine, University of Lisbon (FMV-UTL), Lisboa, Portugal.
Int J Food Microbiol. 2016 Nov 7;236:107-14. doi: 10.1016/j.ijfoodmicro.2016.07.020. Epub 2016 Jul 15.
Forty enterococci isolated along the production chains of three traditional cheeses (PDO Pecorino Siciliano, PDO Vastedda della Valle del Belìce, and Caciocavallo Palermitano) made in Sicily (southern Italy) were studied for the assessment of their antibiotic resistance and virulence by a combined phenotypic/genotypic approach. A total of 31 Enterococcus displayed resistance to at least one or more of the antimicrobials tested. The strains exhibited high percentages of resistance to erythromycin (52.5%), ciprofloxacin (35.0%), quinupristin-dalfopristin (20.0%), tetracycline (17.5%), and high-level streptomycin (5.0%). The presence of tet(M), cat(pC221), and aadE genes for resistance to tetracycline, chloramphenicol, and streptomycin, respectively, was registered in all strains with resistance phenotype. The erm(B) gene was not detected in any erythromycin-resistant strain. The Enterococcus strains were further tested by PCR for the presence of virulence genes, namely, gelE, asa1, efaA, ace, and esp. Twenty strains were positive for all virulence genes tested. Among the enterococci isolated from final cheeses, three strains (representing 33.3% of total cheese strains) were sensible to all antimicrobials tested and did not carry any virulence factor. Although this study confirmed that the majority of dairy enterococci are vectors for the dissemination of antimicrobial resistance and virulence genes, only two strains showed a high resistance to aminoglycosides, commonly administered to combat enterococci responsible for human infections. Furthermore, the presence of the strains E. casseliflavus FMAC163, E. durans FMAC134B, and E. faecium PON94 without risk determinants, found at dominating levels over the Enterococcus populations in the processed products, stimulates further investigations for their future applications in cheese making. All strains devoid of the undesired traits were isolated from stretched cheeses. Thus, this cheese typology represents an interesting environment to deepen the studies on the risk/benefit role of enterococci in fermented foods for their qualified presumption of safety (QPS) assessment.
对从意大利南部西西里岛生产的三种传统奶酪（受保护的原产地名称佩科里诺·西西里诺奶酪、受保护的原产地名称贝利塞河谷瓦斯泰德达奶酪和巴勒莫卡乔卡瓦洛奶酪）生产链中分离出的40株肠球菌，采用表型/基因型联合方法研究其抗生素抗性和毒力。共有31株肠球菌对至少一种或多种测试抗菌药物表现出抗性。这些菌株对红霉素（52.5%）、环丙沙星（35.0%）、奎奴普丁-达福普汀（20.0%）、四环素（17.5%）和高水平链霉素（5.0%）表现出较高的抗性百分比。在所有具有抗性表型的菌株中均检测到分别对四环素、氯霉素和链霉素耐药的tet(M)、cat(pC221)和aadE基因。在任何耐红霉素菌株中均未检测到erm(B)基因。通过PCR进一步检测肠球菌菌株是否存在毒力基因，即gelE、asa1、efaA、ace和esp。20株菌株对所有测试的毒力基因均呈阳性。在从最终奶酪中分离出的肠球菌中，有三株菌株（占奶酪总菌株的33.3%）对所有测试抗菌药物敏感，且不携带任何毒力因子。尽管这项研究证实大多数乳制品肠球菌是抗菌药物抗性和毒力基因传播的载体，但只有两株菌株对通常用于对抗引起人类感染的肠球菌的氨基糖苷类药物表现出高抗性。此外，在加工产品中，发现无风险决定因素的格氏肠球菌FMAC163、耐久肠球菌FMAC134B和粪肠球菌PON94菌株在肠球菌种群中占主导水平，这促使对它们未来在奶酪制作中的应用进行进一步研究。所有不具有不良特性的菌株均从拉伸奶酪中分离得到。因此，这种奶酪类型代表了一个有趣的环境，可用于深入研究肠球菌在发酵食品中基于其合格安全推定（QPS）评估的风险/益处作用。
