The present study investigated the genomic constitution and antimicrobial resistance (AMR) of 238 Campylobacter from pigs and wild boars in Italy between 2012 and 2019. Campylobacter strains were genotyped using multilocus sequence typing (MLST) and whole genome MLST (wgMLST), screened for antimicrobial resistance genes, and tested for phenotypic susceptibility to six different antibiotics. C. coli was detected in 98.31% and 91.66% of pigs and wild boars, while C. jejuni was isolated in the remaining cases. MLST assigned 73 STs and 13 STs in pigs and wild boars, respectively, including 44 novel STs. The predominant ST in pigs was ST-854 (12.36%), followed by ST-9264 (6.18%). ST-1055 and ST-1417 were predominant in wild boars (30% and 13.33%, respectively). The minimum spanning tree using 1,121 global MLST profiles showed specific Italian clusters and a clear separation between pig and wild boar profiles. The wgMLST confirmed the MLST clustering and revealed a high genetic diversity within C. coli population in Italy. Minimum inhibitory concentrations (MIC) of six antibiotics revealed higher resistance in pigs to ciprofloxacin, nalidixic acid, streptomycin and tetracycline, compared to wild boar. In contrast, most strains were susceptible to gentamicin. Worrying levels of multidrug resistance (MDR) were observed mostly in pig isolates. Molecular screening of AMR mechanisms revealed the predominance of gyrA T86I substitution among fluoroquinolone- and quinolone-resistant isolates, and the 23S rRNA A2075G mutation among macrolide-resistant isolates. Other resistance determinants were observed: (i) tet(O) gene was present among tetracycline-resistant isolates; (ii) rpsL and aph(3’)-III genes conferring resistance to aminoglycosides, were identified only in streptomycin or gentamicin-resistant pig isolates; (iii) cmeA, cmeB, cmeC, cmeR genes responsible of pump efflux mechanisms, were observed in almost all the strains; (iv) OXA-61, encoding β-lactamase, was found in the half of the strains. Genotypic and phenotypic AMR profiling was fairly correlated for quinolones/fluoroquinolones. Campylobacter infection is common also in wild boar populations in Italy, suggesting that wild boars could be a reservoir of resistant and multi-resistant Campylobacter species, which may be of public health concern. The present study adds to our knowledge on the epidemiological and ecological traits of this pathogen in domesticated and wild swine.

本研究调查了 2012 年至 2019 年间来自意大利猪和野猪的 238 种弯曲杆菌的基因组构成和抗菌药物耐药性 (AMR)。使用多位点序列分型 (MLST) 和全基因组 MLST (wgMLST) 对弯曲杆菌菌株进行基因分型，筛选抗菌药物抗性基因，并测试了对六种不同抗生素的表型敏感性。 98.31%和91.66%的猪和野猪检出大肠杆菌，其余病例检出空肠弯曲菌。 MLST在猪和野猪中分别分配了73个ST和13个ST，其中包括44个新ST。猪中最主要的 ST 是 ST-854 (12.36%)，其次是 ST-9264 (6.18%)。 ST-1055 和 ST-1417 在野猪中占主导地位（分别为 30% 和 13.33%）。使用 1,121 个全球 MLST 概况的最小生成树显示了特定的意大利集群以及猪和野猪概况之间的明显分离。 wgMLST 证实了 MLST 聚类，并揭示了意大利大肠杆菌种群内的高度遗传多样性。六种抗生素的最低抑菌浓度（MIC）显示，与野猪相比，猪对环丙沙星、萘啶酸、链霉素和四环素具有更高的耐药性。相反，大多数菌株对庆大霉素敏感。主要在猪分离株中观察到令人担忧的多药耐药性（MDR）水平。 AMR机制的分子筛选揭示了氟喹诺酮类和喹诺酮类耐药菌株中gyrA T86I取代占主导地位，大环内酯类耐药菌株中23S rRNA A2075G突变占主导地位。 观察到其他耐药性决定因素：(i) 四环素耐药菌株中存在 tet(O) 基因； (ii) rpsL 和 aph(3')-III 基因赋予对氨基糖苷类药物的抗性，仅在链霉素或庆大霉素抗性猪分离株中被鉴定； (iii)几乎所有菌株中都观察到负责泵流出机制的cmeA、cmeB、cmeC、cmeR基因； (iv) 在一半菌株中发现了编码β-内酰胺酶的OXA-61。喹诺酮类/氟喹诺酮类药物的基因型和表型 AMR 分析相当相关。弯曲杆菌感染在意大利的野猪种群中也很常见，这表明野猪可能是耐药和多重耐药弯曲杆菌物种的储存库，这可能会引起公共卫生问题。本研究增加了我们对该病原体在家养猪和野猪中的流行病学和生态特征的了解。