This study was performed to elucidate genetic relatedness and molecular resistance mechanisms of AmpC-producing multidrug-resistant Proteus mirabilis isolates in University Hospital of Split (UHS), and define efficient antibiotics in vitro. A total of 100 nonrepeated, consecutive, amoxicillin/clavulanate- and cefoxitin-resistant P. mirabilis isolates were collected, mostly from urine (44%) and skin and soft-tissue samples (30%). They were all positive in cefoxitin Hodge test and negative for extended spectrum beta-lactamase production. Pulsed field gel electrophoresis identified four clusters and two singletons, with 79% of isolates in dominant cluster. Molecular characterization and I-CeuI analysis of representatives revealed bla_CMY-16 gene located on chromosome, and insertion element ISEcp1 positioned 110 pb upstream of bla_CMY-16 starting codon. They also harbored bla_TEM-1, except one with bla_TEM-2. They were all resistant to trimethoprim-sulfamethoxazole, all but one to quinolones, and 81% to all aminoglycosides, while 77% were susceptible (S) and 22% intermediate (I) to piperacillin/tazobactam, and 4% were S and 68% I to cefepime. Only 15% were S to ceftolozane/tazobactam. Meropenem, ertapenem, ceftazidime/avibactam, temocillin, and fosfomycin were 100% efficient in vitro. This is the first report of bla_CMY-16 gene in P. mirabilis from hospital samples in Croatia. The findings are in accordance with Italian and Greek reports. The clonal nature of outbreak suggests the high potential of clonal spread. Alternative agents should be considered to spare carbapenem usage.

中文翻译：

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克罗地亚斯普利特大学医院中产生 AmpC 的多药耐药奇异变形杆菌的 β-内酰胺耐药性和抗菌药物敏感性的分子表征

本研究旨在阐明斯普利特大学医院 (UHS)产生 AmpC 的多重耐药奇异变形杆菌的遗传相关性和分子耐药机制，并在体外定义有效的抗生素。总共收集了 100 个非重复、连续、阿莫西林/克拉维酸和头孢西丁耐药的奇异变形杆菌分离株，主要来自尿液 (44%) 和皮肤和软组织样本 (30%)。他们在头孢西丁 Hodge 试验中均呈阳性，而超广谱 β-内酰胺酶产生呈阴性。脉冲场凝胶电泳鉴定了四个簇和两个单例，其中 79% 的分离株处于优势簇中。代表的分子表征和IC euI 分析揭示bla _CMY-16基因位于染色体上，插入元件 IS Ecp1位于bla _CMY-16起始密码子上游 110 pb 。他们还藏着BLA _{TEM-1 ，}除了一个与BLA _TEM-2 。他们都对甲氧苄氨嘧啶-磺胺甲恶唑耐药，对喹诺酮类耐药，对所有氨基糖苷类耐药率为 81%，对哌拉西林/他唑巴坦敏感（S）和中间体（I）分别为 77% 和 22%，S 和 68%我要头孢吡肟。只有 15% 是 S 对头孢洛扎/他唑巴坦。美罗培南、厄他培南、头孢他啶/阿维巴坦、替莫西林和磷霉素在体外的有效性为 100% 。这是我国首次报道bla _CMY-16基因来自克罗地亚医院样本的奇异假单胞菌。调查结果与意大利和希腊的报告一致。爆发的克隆性质表明克隆传播的潜力很大。应考虑替代药物以减少碳青霉烯类药物的使用。