Phenotypic and genotypic analysis of biofilm production by Pseudomonas aeruginosa isolates from infection and colonization samples

Abstract INTRODUCTION: Pseudomonas aeruginosa is an opportunistic pathogen associated with healthcare-related infections, affecting mainly patients with underlying diseases and immunosuppression. This microorganism has several virulence mechanisms that favour its pathogenesis, including the production of biofilm. This study aimed to analyze the phenotypic production of biofilms, the occurrence of quorum sensing (QS) genes, and the clonal profile of clinical isolates of P. aeruginosa from colonized/infected patients in a tertiary hospital in Recife-PE. METHODS: We obtained 21 isolates that were classified as infection isolates (II), and 10 colonization isolates (CI). The phenotypic analysis for biofilm production was performed quantitatively. The QS genes were detected by specific PCRs, and the clonal profile was assessed using ERIC-PCR. RESULTS: Of the 31 isolates, 58.1 % (18/31) were biofilm producers, of which 70 % (7/10) were CI and classified as weakly adherent; 52.4 % (11/21) of the II produced biofilms, and were classified as weak (38.1 %, (8/21)), moderate (9.5 %, (2/21)), and strongly adherent (4.8 %, (1/21)). All isolates harbored the QS genes analyzed. In the clonal analysis, 26 distinct genetic profiles were identified, highlighting the presence of a clone in four samples, i.e., one infection isolate, and 3 colonization isolates. CONCLUSIONS: The detection of biofilm formation is important in P. aeruginosa in addition to the identification of colonization and infection isolates, especially from complex environments such as ICUs. Further, we define a strategy for monitoring and analyzing P. aeruginosa strains that can potentially cause infections in hospitalized patients.

Antimicrobial activity of a mixture of two isomeric phenylpropanoid glycosides from Arrabidaes harleyi A.H. Gentry(Bignoniaceae)

Arrabidaea harleyi A.H. Gentry (Bignoniaceae) is an ornamental plant found in some regions of the Atlanticforest in Brazil. From its bark a mixture of verbascoside and isoverbascoside was isolated. This mixture was shown to be active against Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis, Bacillus mycoides, Enterecoccus faecalis, Escherichia coli, Serratia marcensis and Candida albicans. The minimal inhibitory concentration (MIC) was established by diffusion method

Atividade antimicrobiana e antitumoral de Streptoverticillium sp (DAUFPE 13.729) / Antimicrobial and antitumoral activities of Streptoverticillium sp (DAUFPE 13.729)

Streptoverticillium sp, bactéria pertencente a família Streptomycetaceae, foi isolada de amostras de solo do câmpus da Universidade Federal do Pernambuco, e destacou-se pela atividade antibacteriana e antifúngica de seus matabólitos secundários. O extrato etanóico bruto foi submetido ao fracionamento cromatográfigo. Das substâncias isoladas, duas apresentaram atividade antimicrobiana em relação a sete espécies de Candida. Em testes biológicos realizados em camundongos, determinou-se que a maior dose do extrato bruto na qual não houve óbitos foi de 150 mg/kg e todos os animais morreram com a administração de 600 mg/kg. Para o extrato etanóico de Streptoverticillium sp observou-se IC50 de 13 ug/mL e taxa de inibição tumoral igual a 61,5 por cento para o carcinoma de Ehrlich e 75 por cento em animais com sarcoma 180.