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In vitro characterization of Pseudomonas aeruginosa recovered in Portugal from low respiratory tract infections in ICU patients (STEP Study)

2021; Oxford University Press; Volume: 368; Issue: 15 Linguagem: Inglês

10.1093/femsle/fnab099

1574-6968

Marta Hernández-García, Sergio García‐Fernández, María García-Castillo, Leonor Pássaro, Rafael Cantón, José Melo‐Cristino, Margarida Pinto, Cristina Marcelo, Helena Peres, Isabel Lourenço, Isabel Peres, João Lourenço Marques, Odete Chantre, Teresa Casas, Laboratório de Microbiologia, Serviço de Patologia Clínica, Elsa Gonçalves, Cristina Toscano, Valquíria Alves, Serviço de Microbiologia, Manuela Ribeiro, Eliana Costa, Ana Raquel Vieira, Serviço Patologia Clínica, S. Ferreira, Raquel Diaz, Elmano Ramalheira, Serviço Patologia Clínica, Sandra Schäfer, Luísa Tancredo, Luísa Sancho, Serviço de Patologia Clínica, Ana Maria Rodrigues, José Diogo, Serviço de Microbiologia, Rui M. Ferreira, Helena Ramos, Tânia Silva, Daniela Silva, Serviço de Microbiologia, Catarina Chaves, Carolina Queiroz, Altair Nabiev, Serviço de Microbiologia, Leonor Pássaro, Laura Paixão, João Romano, Carolina Soares Moura, María García del Castillo, Sergio García‐Fernández, Marta Hernández-García, Rafael Cantón,

Antibiotics Pharmacokinetics and Efficacy

ABSTRACT Purpose: to characterize the distribution and mechanisms involved in ceftolozane/tazobactam (C/T) resistance in Pseudomonas aeruginosa isolates recovered from intensive care units (ICUs) in Portugal as part of the STEP surveillance study. Materials and methods: a total of 226 P. aeruginosa isolates were collected from patients with low respiratory tract infections (LRTI) admitted to ICUs between June 2017 and July 2018. Susceptibility to antimicrobials including the recent C/T combination was determined by EUCAST-criteria. Whole genome sequencing (WGS) was performed in a subset of 17 isolates. Results: multidrug resistant (MDR) and extremely drug resistant (XDR) phenotypes accounted for 20.4% and 25.7% of cases, respectively. C/T showed the highest susceptibility rate in both MDR (100%) and XDR (93.1%) isolates, followed by amikacin (97.8% MDR and 79.3% XDR). blaKPC-3 (n = 2) and blaGES-13 (n = 1) carbapenemase genes were detected in 3 of the 17 sequenced isolates, but only the GES-13-producing isolate displayed resistance to C/T. Additionally, the C/T-resistant phenotype was also found in two non-carbapenemase producers that carried known ceftolozane/tazobactam resistance-associated mutations in the PBP3 gene. Conclusions: C/T was highly active against MDR/XDR-P. aeruginosa isolates causing LRTI in ICUs. Moreover, beyond carbapenemase-encoding genes, mutations in chromosomal PBP-encoding genes might also be involved in ceftolozane/tazobactam resistance in Portugal.