Massella Elisa, Russo Simone, Filippi Anita, Garbarino Chiara Anna, Ricchi Matteo, Bassi Patrizia, Toschi Elena, Torreggiani Camilla, Pupillo Giovanni, Rugna Gianluca, Carta Valentina, Bertasio Cristina, Di Cesare Andrea, Sbaffi Tomasa, Borgomaneiro Giulia, Luppi Andrea
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Strada Faggiola 1, Gariga di Podenzano, 29027 Piacenza, Italy.
Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Pietro Fiorini 5, 40127 Bologna, Italy.
Antibiotics (Basel). 2025 Aug 8;14(8):814. doi: 10.3390/antibiotics14080814.
: Vancomycin-resistant enterococci (VRE) are significant nosocomial pathogens worldwide, potentially transmitted by food-producing animals and related products. This study investigates the epidemiological role of bovine raw milk in the transmission of VRE to humans. : Bulk milk samples were screened for gene presence using a multiplex PCR. Mastitogenic enterococci isolated from individual milk samples were tested for antimicrobial susceptibility using the broth microdilution method. Strains not susceptible to vancomycin were whole genome sequenced. : Overall, genes were detected in 299/1026 (29.14%) bulk milk samples. Specifically, was found in 204 samples (19.88%) and in 57 samples (5.56%), with both detected simultaneously in 38 samples (3.70%). Clinically significant and genes were not identified. A total of 163 mastitogenic strains were isolated from individual milk samples. Eight different species were detected, with (104/163, 63.80%) and (34/163, 20.86%) being the most common. Multidrug resistance was observed in 106/163 (65.03%) isolates. The most common resistance frequencies were to ciprofloxacin and erythromycin (102/163, 62.58% both), followed by quinupristin/dalfopristin (93/163, 57.06%), linezolid (65/163, 39.88%), tetracycline (58/163, 35.58%), daptomycin (46/163, 28.22%), chloramphenicol (33/163, 20.25%), ampicillin, tigecycline, and high-dosage gentamycin (8/163, 4.91% all). Resistance to teicoplanin was not observed. Two vancomycin non-susceptible strains were identified: one and one . Whole genome sequencing confirmed the presence of the complete gene cluster and several virulence genes in both strains. : Our findings suggest that while raw milk is unlikely to be a source of vancomycin resistance genes of highest clinical importance ( or ), it may contribute to the spread of enterococci, which are increasingly associated with human infections.
耐万古霉素肠球菌（VRE）是全球重要的医院病原体，可能通过食用动物及其相关产品传播。本研究调查了生牛乳在VRE传播给人类过程中的流行病学作用。：使用多重PCR对散装牛奶样本进行基因检测。从单个牛奶样本中分离出的致乳腺炎肠球菌，采用肉汤微量稀释法检测其抗菌药敏性。对万古霉素不敏感的菌株进行全基因组测序。：总体而言，在299/1026（29.14%）的散装牛奶样本中检测到了基因。具体而言，在204个样本（19.88%）中发现了，在57个样本（5.56%）中发现了，在38个样本（3.70%）中同时检测到了这两种基因。未鉴定出具有临床意义的和基因。从单个牛奶样本中总共分离出163株致乳腺炎菌株。检测到8种不同的物种，其中（104/163，63.80%）和（34/163，20.86%）最为常见。在106/163（65.03%）的分离株中观察到多重耐药性。最常见的耐药频率是对环丙沙星和红霉素（均为102/163，62.58%），其次是对奎奴普丁/达福普汀（93/163，57.06%）、利奈唑胺（65/163，39.88%）、四环素（58/163，35.58%）、达托霉素（46/163，28.22%）、氯霉素（33/163，20.25%）、氨苄西林、替加环素和高剂量庆大霉素（均为8/163，4.91%）。未观察到对替考拉宁的耐药性。鉴定出两株对万古霉素不敏感的菌株：一株和一株。全基因组测序证实这两株菌株中均存在完整的基因簇和几个毒力基因。：我们的研究结果表明，虽然生牛奶不太可能是具有最高临床重要性的万古霉素耐药基因（或）的来源，但它可能有助于肠球菌的传播，而肠球菌与人类感染的相关性日益增加。
