Table_3_Antibiotic Resistance Patterns of Pseudomonas spp. Isolated From Raw Milk Revealed by Whole Genome Sequencing.DOCX

Psychrotrophic bacteria in raw milk are most well known for their spoilage potential and the economic losses they cause to the dairy industry. Food-related psychrotrophic bacteria are increasingly reported to have antibiotic resistance features. The aim of this study was to evaluate the resistance patterns of Pseudomonas spp. isolated from bulk-tank milk. In total, we investigated the antibiotic susceptibility profiles of 86 Pseudomonas spp. isolates from raw milk. All strains were tested against 15 antimicrobial agents. Pseudomonas isolates were most highly resistant to imipenem (95.3%), followed by trimethoprim-sulfamethoxazole (69.8%), aztreonam (60.5%), chloramphenicol (45.3%), and meropenem (27.9%). Their multiple antibiotic resistance (MAR) index values ranged from 0.0 to 0.8. Whole-genome sequencing revealed the presence of intrinsic resistance determinants, such as BcI, ampC-09, blaCTX-M, oprD, sul1, dfrE, catA1, catB3, catI, floR, and cmlV. Moreover, resistance-nodulation-cell division (RND) and ATP-binding cassette (ABC) antibiotic efflux pumps were also found. This study provides further knowledge of the antibiotic resistance patterns of Pseudomonas spp. in milk, which may advance our understanding of resistance in Pseudomonas and suggests that antibiotic resistance of Pseudomonas spp. in raw milk should be a concern.

生乳中的嗜冷菌（psychrotrophic bacteria）以其腐败潜力及给乳制品行业造成的经济损失而广为人知。与食品相关的嗜冷菌的抗生素耐药特性正被越来越多地报道。本研究旨在评估从集乳罐牛奶中分离的假单胞菌属（Pseudomonas spp.）的耐药谱。本研究共调查了86株从生乳中分离的假单胞菌属分离株的抗生素敏感性谱。所有菌株均针对15种抗菌剂开展了药敏测试。假单胞菌属分离株对亚胺培南的耐药率最高，达95.3%；其次为甲氧苄啶-磺胺甲恶唑（69.8%）、氨曲南（60.5%）、氯霉素（45.3%）和美罗培南（27.9%）。其多重抗生素耐药（MAR）指数的取值范围为0.0至0.8。全基因组测序结果显示，菌株携带多种固有耐药决定因子，包括BcI、ampC-09、blaCTX-M、oprD、sul1、dfrE、catA1、catB3、catI、floR及cmlV。此外，还检出了耐药结节化细胞分化（RND）型与ATP结合盒（ABC）型抗生素外排泵。本研究进一步阐明了乳源假单胞菌属的抗生素耐药谱，有助于加深我们对假单胞菌属耐药性的认知，同时提示生乳中假单胞菌属的抗生素耐药性应当引起重视。