Class D β-lactamases OXA-232 and OXA-48 hydrolyze penicillin, cephalosporins and carbapenems, limiting the pharmacological therapeutics in bacteraemia. OXA producer microorganisms are considered a great emergent threat, especially in nosocomial environments. To determine the resistance profile and genomic characterization of two isolates initially identified as potential carbapenemase-producer Klebsiella oxytoca in a third level hospital. Automated platform BD Phoenix-100 System was used to identify and to biochemically characterize both isolates. Furthermore, the resistance profile was determined through CLSI methods and the whole genome sequences were obtained using Next-Generation Sequencing. Resistance genes were analyzed, and the virtual fingerprinting was determined to corroborate the similarity with related bacteria. Both strains correspond to Raoultella ornithinolytica carrying OXA 232 and OXA-48 genes, confirming the class D β-lactamases assay results. Here, we present the genetic and phenotypic analysis of multidrug resistance R. ornithinolytica, representing the first report in Mexico.

D 类 β-内酰胺酶 OXA-232 和 OXA-48 水解青霉素、头孢菌素和碳青霉烯，限制了菌血症的药理治疗。OXA 生产者微生物被认为是一个巨大的紧急威胁，尤其是在医院环境中。确定最初被鉴定为潜在的产碳青霉烯酶克雷伯氏菌的两种分离株的耐药谱和基因组特征在三级医院。自动化平台 BD Phoenix-100 系统用于鉴定和生化表征这两种分离株。此外，通过 CLSI 方法确定抗性谱，并使用下一代测序获得全基因组序列。分析抗性基因，并确定虚拟指纹以证实与相关细菌的相似性。两种菌株都对应于携带 OXA 232 和 OXA-48 基因的Raoultella ornithinolytica，证实了 D 类 β-内酰胺酶测定结果。在这里，我们介绍了多药耐药性R. ornithinolytica的遗传和表型分析，这是墨西哥的第一份报告。