Article
Virulence attributes in Brazilian clinical isolates of Pseudomonasaeruginosa
Registro en:
SILVA, Lìvia V. et al. Virulence attributes in Brazilian clinical isolates of Pseudomonasaeruginosa. International Journal of Medical Microbiology, v.304, n.8, p.990–100, Nov. 2014.
1438-4221
10.1016/j.ijmm.2014.07.001
Autor
Silva, Lívia V.
Galdino, Anna Clara M.
Nunes, Ana Paula F.
Santos, Kátia R. N. dos
Moreira, Beatriz M.
Cacci, Luciana C.
Sodré, Catia I.
Ziccardi, Mariangela
Branquinha, Marta H.
Santos, André L. S.
Resumen
Pseudomonas aeruginosa is an opportunistic human pathogen responsible for causing a huge variety ofacute and chronic infections with significant levels of morbidity and mortality. Its success as a pathogencomes from its genetic/metabolic plasticity, intrinsic/acquired antimicrobial resistance, capacity to formbiofilm and expression of numerous virulence factors. Herein, we have analyzed the genetic variabil-ity, antimicrobial susceptibility as well as the production of metallo- -lactamases (MBLs) and virulenceattributes (elastase, pyocyanin and biofilm) in 96 strains of P. aeruginosa isolated from different anatom-ical sites of patients attended at Brazilian hospitals. Our results revealed a great genetic variability, inwhich 86 distinct RAPD types (89.6% of polymorphisms) were detected. Regarding the susceptibilityprofile, 48 strains (50%) were resistant to the antimicrobials, as follows: 22.92% to the three tested antibi-otics, 12.5% to both imipenem and meropenem, 11.46% to ceftazidime only, 2.08% to imipenem onlyand 1.04% to both ceftazidime and meropenem. Out of the 34 clinical strains of P. aeruginosa resistantto 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, elastaseand biofilm, although in different levels. Some associations were demonstrated among the susceptibilityand/or production of these virulence traits with the anatomical site of strain isolation. For instance, almostall strains isolated from urine (85.71%) were resistant to the three antibiotics, while the vast majority ofstrains isolated from rectum (95%) and mouth (66.67%) were susceptible to all tested antibiotics. Urineisolates produced the highest pyocyanin concentration (20.15 ± 5.65 g/ml), while strains isolated frompleural secretion and mouth produced elevated elastase activity (1441.43 ± 303.08 FAU) and biofilm for-mation (OD5900.676 ± 0.32), respectively. Also, MBL-positive strains produced robust biofilm comparedto MBL-negative strains. Collectively, the production of site-dependent virulence factors can be high-lighted as potential therapeutic targets for the treatment of infections caused by heterogeneous andresistant strains of P. aeruginosa.