Although most of the approximately 94 million annual human cases of gastroenteritis due to Salmonella enterica resolve without medical intervention, antimicrobial therapy is recommended for patients with severe disease. Wild birds can be natural hosts of Salmonella that pose a threat to human health; however, multiple-drug-resistant serovars of S. enterica have rarely been described. In 2012, silver gull (Chroicocephalus novaehollandiae) chicks at a major breeding colony were shown to host Salmonella, most isolates of which were susceptible to antibiotics. However, multiple-drug-resistant (MDR) Escherichia coli with resistance to carbapenems, ceftazidime, and fluoroquinolones was reported from this breeding colony. In this paper, we describe a novel MDR Salmonella strain subsequently isolated from the same breeding colony. SG17-135, an isolate of S. enterica with phenotypic resistance to 12 individual antibiotics but only nine antibiotic classes including penicillins, cephalosporins, monobactams, macrolides, fluoroquinolones, aminoglycosides, dihydrofolate reductase inhibitors (trimethoprim), sulfonamides, and glycylcyclines was recovered from a gull chick in 2017. Whole-genome sequence (WGS) analysis of SG17-135 identified it as Salmonella enterica serovar Agona (S. Agona) with a chromosome comprising 4,813,284 bp, an IncHI2 ST2 plasmid (pSG17-135-HI2) of 311,615 bp, and an IncX1 plasmid (pSG17-135-X) of 27,511 bp. pSG17-135-HI2 housed a complex resistance region comprising 16 antimicrobial resistance genes including bla_CTX-M-55. The acquisition of MDR plasmids by S. enterica described here poses a serious threat to human health. Our study highlights the importance of taking a One Health approach to identify environmental reservoirs of drug-resistant pathogens and MDR plasmids.

中文翻译：

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来自澳大利亚银鸥 (Chroicocephalus novaehollandiae) 的广泛耐药肠沙门氏菌 Serovar Agona 分离株的全基因组序列分析揭示了多药耐药质粒的获得

尽管每年大约 9400 万例由肠道沙门氏菌引起的人类胃肠炎病例中的大部分在没有医疗干预的情况下得到解决，但建议对重症患者进行抗生素治疗。野生鸟类可能是对人类健康构成威胁的沙门氏菌的天然宿主；然而，很少有关于肠道沙门氏菌的多重耐药血清型的报道。2012 年，一个主要繁殖群的银鸥 ( Chroicocephalus novaehollandiae ) 雏鸡被证明是沙门氏菌的宿主，沙门氏菌的大多数分离株对抗生素敏感。然而，多重耐药（MDR）大肠杆菌据报道，该繁殖群对碳青霉烯类、头孢他啶和氟喹诺酮类药物具有抗性。在本文中，我们描述了一种新的 MDR沙门氏菌菌株，随后从同一繁殖群中分离出来。SG17-135，一种对 12 种抗生素具有表型抗性的肠链球菌分离株，但仅从青霉素、头孢菌素、单内酰胺类、大环内酯类、氟喹诺酮类、氨基糖苷类、二氢叶酸还原酶抑制剂（甲氧苄啶）、磺胺类和甘氨酰环素类中回收了 9 类抗生素类2017 年的海鸥雏鸡。 SG17-135 的全基因组序列 (WGS) 分析将其鉴定为沙门氏菌血清型 Agona ( S. Agona) 的染色体包含 4,813,284 bp、311,615 bp 的 IncHI2 ST2 质粒 (pSG17-135-HI2) 和 27,511 bp 的 IncX1 质粒 (pSG17-135-X)。pSG17-135-HI2 包含一个复杂的耐药区域，包括bla _CTX-M-55在内的 16 个抗微生物基因。此处描述的S. enterica获得 MDR 质粒对人类健康构成严重威胁。我们的研究强调了采用 One Health 方法来确定耐药病原体和 MDR 质粒的环境储存库的重要性。