title: Virulence attributes in Brazilian clinical isolates of Pseudomonas aeruginosa.
abstract: Pseudomonas aeruginosa is an opportunistic human pathogen responsible for causing a huge variety of acute and chronic infections with significant levels of morbidity and mortality. Its success as a pathogen comes from its genetic/metabolic plasticity, intrinsic/acquired antimicrobial resistance, capacity to form biofilm and expression of numerous virulence factors. Herein, we have analyzed the genetic variability, antimicrobial susceptibility as well as the production of metallo-β-lactamases (MBLs) and virulence attributes (elastase, pyocyanin and biofilm) in 96 strains of P. aeruginosa isolated from different anatomical sites of patients attended at Brazilian hospitals. Our results revealed a great genetic variability, in which 86 distinct RAPD types (89.6% of polymorphisms) were detected. Regarding the susceptibility profile, 48 strains (50%) were resistant to the antimicrobials, as follows: 22.92% to the three tested antibiotics, 12.5% to both imipenem and meropenem, 11.46% to ceftazidime only, 2.08% to imipenem only and 1.04% to both ceftazidime and meropenem. Out of the 34 clinical strains of P. aeruginosa resistant to both imipenem and meropenem, 25 (73.53%) were MBL producers by phenotypic method while 12 (35.29%) were PCR positive for the MBL gene SPM-1. All P. aeruginosa strains produced pyocyanin, elastase and biofilm, although in different levels. Some associations were demonstrated among the susceptibility and/or production of these virulence traits with the anatomical site of strain isolation. For instance, almost all strains isolated from urine (85.71%) were resistant to the three antibiotics, while the vast majority of strains isolated from rectum (95%) and mouth (66.67%) were susceptible to all tested antibiotics. Urine isolates produced the highest pyocyanin concentration (20.15±5.65 μg/ml), while strains isolated from pleural secretion and mouth produced elevated elastase activity (1441.43±303.08 FAU) and biofilm formation (OD590 0.676±0.32), respectively. Also, MBL-positive strains produced robust biofilm compared to MBL-negative strains. Collectively, the production of site-dependent virulence factors can be highlighted as potential therapeutic targets for the treatment of infections caused by heterogeneous and resistant strains of P. aeruginosa.
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Lívia V
authors.initials: LV
authors.lastname: Silva
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Anna Clara M
authors.initials: AC
authors.lastname: Galdino
authors.affiliation: Departamento de Patologia e Programa de Pós-Graduação em Doenças Infecciosas, Universidade Federal do Espírito Santo, Espírito Santo, Brazil.
authors.forename: Ana Paula F
authors.initials: AP
authors.lastname: Nunes
authors.affiliation: Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Kátia R N
authors.initials: KR
authors.lastname: dos Santos
authors.affiliation: Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Beatriz M
authors.initials: BM
authors.lastname: Moreira
authors.affiliation: Programa de Pós-Graduação em Doenças Infecciosas e Parasitárias, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Luciana C
authors.initials: LC
authors.lastname: Cacci
authors.affiliation: Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brazil.
authors.forename: Cátia L
authors.initials: CL
authors.lastname: Sodré
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil.
authors.forename: Mariangela
authors.initials: M
authors.lastname: Ziccardi
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Marta H
authors.initials: MH
authors.lastname: Branquinha
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; Programa de Pós-Graduação em Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil. Electronic address: andre@micro.ufrj.br.
authors.forename: André L S
authors.initials: AL
authors.lastname: Santos
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000254:growth & development; D001826:Body Fluids / Q000382:microbiology; D001938:Brazil; D024881:Drug Resistance, Bacterial; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D011552:Pseudomonas Infections / Q000382:microbiology*; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification* / Q000502:physiology; D019105:Random Amplified Polymorphic DNA Technique; D014774:Virulence; D037521:Virulence Factors / Q000235:genetics*; D001618:beta-Lactamases / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors; D001618:beta-Lactamases
keywords: Antimicrobial resistance; Biofilm; Brazilian clinical strains; Elastase; Genetic variability; Metallo-β-lactamase; Pseudomonas aeruginosa; Pyocyanin; SPM-1 gene; Virulence factors