Pseudomonas is ubiquitous in nature and a predominant genus in many foods and food processing environments, where it primarily represents major food spoilage organisms. The food chain has also been reported to be a potential reservoir of antibiotic-resistant Pseudomonas. The purpose of the current study was to determine the occurrence of antibiotic resistance in psychrotrophic Pseudomonas spp. collected over a time span of 26 years from retail chicken in Norway and characterize their genetic diversity, phylogenetic distribution and resistance genes through whole-genome sequence analyses. Among the 325 confirmed Pseudomonas spp. isolates by 16S rRNA gene sequencing, antibiotic susceptibility profiles of 175 isolates to 12 antibiotics were determined. A subset of 31 isolates being resistant to ≥3 antibiotics were whole-genome sequenced. The isolates were dominated by species of the P. fluorescens lineage. Isolates susceptible to all antibiotics or resistant to ≥3 antibiotics comprised 20.6% and 24.1%, respectively. The most common resistance was to aztreonam (72.6%), colistin (30.2%), imipenem (25.6%) and meropenem (12.6%). Resistance properties appeared relatively stable over the 26-year study period but with taxa-specific differences. Whole-genome sequencing showed high genome variability, where isolates resistant to ≥3 antibiotics belonged to seven species. A single metallo-betalactmase gene (cphA) was detected, though intrinsic resistance determinants dominated, including resistance–nodulation (RND), ATP-binding cassette (ABC) and small multidrug resistance (Smr) efflux pumps. This study provides further knowledge on the distribution of psychrotrophic Pseudomonas spp. in chicken meat and their antibiotic resistance properties. Further monitoring should be encouraged to determine food as a source of antibiotic resistance and maintain the overall favorable situation with regard to antibiotic resistance in the Norwegian food chain.

中文翻译：

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假单胞菌的抗生素抗性和系统发育。从挪威食物链的鸡肉中分离出三个十年

假单胞菌在自然界无处不在，并且在许多食品和食品加工环境中占主导地位，主要代表主要的食物腐败生物。食物链也据报道是潜在的抗药性假单胞菌。本研究的目的是确定精神营养型假单胞菌属菌种中抗生素耐药性的发生。从挪威的零售鸡中收集了长达26年的时间，并通过全基因组序列分析表征了它们的遗传多样性，系统发育分布和抗性基因。在325例确诊的假单胞菌中spp。通过16S rRNA基因测序，分离出175株分离物对12种抗生素的敏感性。对全基因组测序了31种对≥3种抗生素具有抗性的菌株。分离株以荧光假单胞菌谱系的种为主。对所有抗生素敏感或对≥3种抗生素具有抗药性的分离株分别占20.6％和24.1％。最常见的抗药性是对氨曲南（72.6％），粘菌素（30.2％），亚胺培南（25.6％）和美罗培南（12.6％）。在26年的研究期内，抗药性似乎相对稳定，但存在分类群差异。全基因组测序显示出高的基因组变异性，其中对≥3种抗生素具有抗性的分离株属于七个物种。单个金属-内分泌酶基因（cphA尽管内在的抗药性决定因素占主导，包括抗结瘤（RND），ATP结合盒（ABC）和小型多药抗药性（Smr）外排泵，但还是可以检测到。这项研究提供了有关精神营养假单胞菌属的分布的进一步知识。在鸡肉中及其抗药性。应鼓励进一步监测以确定食物是否是抗生素耐药性的来源，并在挪威食物链中保持总体上有利的耐药性状况。