Intraclonal Genome Stability of the Metallo-beta-lactamase SPM-1-producing Pseudomonas aeruginosa ST277, an Endemic Clone Disseminated in Brazilian Hospitals

• Autor(a) principal: Nascimento, Ana P. B.
• Data de Publicação: 2016
• Outros Autores: Ortiz, Mauro F., Martins, Willames Marcos Brasileiro da Silva [UNIFESP], Morais, Guilherme L., Fehlberg, Lorena Cristina Corrêa [UNIFESP], Almeida, Luiz G. P., Ciapina, Luciane P., Gales, Ana Cristina [UNIFESP], Vasconcelos, Ana T. R.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://dx.doi.org/10.3389/fmicb.2016.01946; https://repositorio.unifesp.br/handle/11600/56558
• topic: drug resistance; comparative genomics; pathogenic bacteria; antimicrobial resistance; carbapenemase; Gram-negative bacilli

Carbapenems represent the mainstay therapy for the treatment of serious P aeruginosa infections. However, the emergence of carbapenem resistance has jeopardized the clinical use of this important class of compounds. The production of SPM-1 metallo-beta-lactamase has been the most common mechanism of carbapenem resistance identified in P. aeruginosa isolated from Brazilian medical centers. Interestingly, a single SPM-1-producing P. aeruginosa clone belonging to the ST277 has been widely spread within the Brazilian territory. In the current study, we performed a next-generation sequencing of six SPM-1-producing P. aeruginosa ST277 isolates. The core genome contains 5899 coding genes relative to the reference strain P. aeruginosa PAO1. A total of 26 genomic islands were detected in these isolates. We identified remarkable elements inside these genomic islands, such as copies of the bla(spM-1) gene conferring resistance to carbapenems and a type I-C CRISPR-Cas system, which is involved in protection of the chromosome against foreign DNA. In addition, we identified single nucleotide polymorphisms causing amino acid changes in antimicrobial resistance and virulence-related genes. Together,these factors could contribute to the marked resistance and persistence of the SPM-1-producing P aeruginosa ST277 clone. A comparison of the SPM-1-producing P. aeruginosa ST277 genomes showed that their core genome has a high level nucleotide similarity and synteny conservation. The variability observed was mainly due to acquisition of genomic islands carrying several antibiotic resistance genes.