title: Antimicrobial activity of new green-functionalized oxazoline-based oligomers against clinical isolates.
abstract: BACKGROUND
  The search for new antimicrobial compounds able to overcome the global issue of microbial resistance to antibiotics is a priority worldwide. Moreover, several commensal microorganisms have been increasingly associated to opportunistic microbial infections. Having previously disclosed the green synthesis and preliminary characterization of the oligomers [linear oligo(ethylenimine) hydrochloride and oligo(2-methyl-2-oxazoline) quaternized with N,N-dimethyldodecylamine] we herein report on the screening of these oligomers against a battery of 69 clinical isolates of Aerococcus spp., Candida spp., Staphylococcus spp. and Streptococcus spp.
  
  
  RESULTS
  The isolates' susceptibility to both oligomers was evaluated by determining their minimal inhibitory concentration (MIC) and the biocidal effectiveness of each compound was further confirmed through spectrophotometric measurements and fluorescence microscopy. The MIC values of the 69 isolates were highly variable, yet favourably comparable with those of other antimicrobial polymers. The viability assays resulted in 100% of microbial killing rate after only 5 min, highlighting the promising antimicrobial action of these oligomers.
  
  
  CONCLUSIONS
  Though further studies are required, evidence suggests that a strong effort should be done in order to confirm these compounds as valid alternatives for several clinical applications. This is reinforced by their well described biocompatibility with human tissues and by their proposed mechanism of action which difficult the development of microbial resistance to these compounds.
authors.affiliation: CiiEM-Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz Quinta da Granja, Campus Universitário, 2829-511 Caparica, Portugal ; Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Celso
authors.initials: C
authors.lastname: Martins
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Vanessa G
authors.initials: VG
authors.lastname: Correia
authors.affiliation: REQUIMTE, Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Aguiar-Ricardo
authors.affiliation: Departamento de Biologia & CESAM, Universidade de Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal.
authors.forename: Ângela
authors.initials: Â
authors.lastname: Cunha
authors.affiliation: CiiEM-Centro de Investigação Interdisciplinar Egas Moniz, Instituto Superior de Ciências da Saúde Egas Moniz Quinta da Granja, Campus Universitário, 2829-511 Caparica, Portugal.
authors.forename: Maria Guilhermina M
authors.initials: MG
authors.lastname: Moutinho
keywords: Antimicrobial oxazolines; Clinical isolates; MIC; Opportunistic pathogens; Viability assay