Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria Illes Balears (IdISBa), Palma de Mallorca, Spain.
Servicio de Microbiología, Hospital Universitario Central de Asturias, Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
Antimicrob Agents Chemother. 2021 Aug 17;65(9):e0098621. doi: 10.1128/AAC.00986-21.
The mechanisms underlying an switch in the resistance phenotype of P. aeruginosa after ceftazidime-avibactam treatment was investigated. The initial isolate (a blood culture) was resistant to meropenem but remained susceptible to antipseudomonal cephalosporins and combinations with β-lactamase inhibitors. One week after ceftazidime-avibactam therapy, a subsequent isolate (a rectal swab) recovered from the same patient showed the opposite phenotype. Whole-genome sequence analysis revealed a single SNP difference between both (ST235) isolates, leading to a P162S change in , creating . Thus, , , and were cloned and expressed in the wild-type strain PAO1. Susceptibility profiles confirmed the P162S substitution reverted the carbapenemase phenotype determined by the G170S change of GES-5 back into the ESBL phenotype of GES-1.
本研究旨在探究铜绿假单胞菌对头孢他啶-阿维巴坦耐药表型转变的机制。初始分离株(血培养)对美罗培南耐药,但对抗假单胞菌头孢菌素和β-内酰胺酶抑制剂复合制剂仍保持敏感。在头孢他啶-阿维巴坦治疗 1 周后,从同一患者中分离出的后续分离株(直肠拭子)表现出相反的表型。全基因组序列分析显示,两株(ST235)分离株之间仅有一个 SNP 差异,导致 中的 P162S 发生改变,形成 。因此,将 、 、 和 克隆并在野生型 PAO1 菌株中表达。药敏谱证实,P162S 取代使由 GES-5 的 G170S 变化决定的碳青霉烯酶表型恢复为 GES-1 的 ESBL 表型。