• Anna Clara M Galdino, Lívia Viganor, Mariangela Ziccardi, Ana Paula F Nunes, Kátia R N Dos Santos, Marta H Branquinha, and André L S Santos.
• Programa de Pós-Graduação em Bioquímica, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; 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.
• Enferm. Infecc. Microbiol. Clin. 2017 Dec 1; 35 (10): 630-637.

BackgroundPseudomonas aeruginosa is an important human pathogen that causes severe infections in a wide range of immunosuppressed patients. Herein, we evaluated the proteolytic profiles of 96 Brazilian clinical isolates of P. aeruginosa recovered from diverse anatomical sites.MethodsCell-associated and extracellular proteases were evidenced by gelatin-SDS-PAGE and by the cleavage of soluble gelatin. Elastase was measured by using the peptide substrate N-succinyl-Ala-Ala-Ala-p-nitroanilide. The prevalence of elastase genes (lasA and lasB) was evaluated by PCR.ResultsBacterial extracts were initially applied on gelatin-SDS-PAGE and the results revealed four distinct zymographic profiles as follows: profile I (composed by bands of 145, 118 and 50kDa), profile II (118 and 50kDa), profile III (145kDa) and profile IV (118kDa). All the proteolytic enzymes were inhibited by EDTA, identifying them as metalloproteases. The profile I was the most detected in both cellular (79.2%) and extracellular (84.4%) extracts. Overall, gelatinase and elastase activities measured in the spent culture media were significantly higher (around 2-fold) compared to the cellular extracts and the production level varied according to the site of bacterial isolation. For instance, tracheal secretion isolates produced elevated amount of gelatinase and elastase measured in both cellular and extracellular extracts. The prevalence of elastase genes revealed that 100% isolates were lasB-positive and 85.42% lasA-positive. Some positive/negative correlations were showed concerning the production of gelatinase, elastase, isolation site and antimicrobial susceptibility.ConclusionThe protease production was highly heterogeneous in Brazilian clinical isolates of P. aeruginosa, which corroborates the genomic/metabolic versatility of this pathogen.Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. All rights reserved.

47 keywords...

hide…