title: SubMICs of penicillin and erythromycin enhance biofilm formation and hydrophobicity of Corynebacterium diphtheriae strains.
abstract: Subinhibitory concentrations (subMICs) of antibiotics may alter bacterial surface properties and change microbial physiology. This study aimed to investigate the effect of a subMIC (&frac18; MIC) of penicillin (PEN) and erythromycin (ERY) on bacterial morphology, haemagglutinating activity, cell-surface hydrophobicity (CSH) and biofilm formation on glass and polystyrene surfaces, as well as the distribution of cell-surface acidic anionic residues of Corynebacterium diphtheriae strains (HC01 tox(-) strain; CDC-E8392 and 241 tox(+) strains). All micro-organisms tested were susceptible to PEN and ERY. Growth in the presence of PEN induced bacterial filamentation, whereas subMIC of ERY caused cell-size reduction of strains 241 and CDC-E8392. Adherence to human erythrocytes was reduced after growth in the presence of ERY, while CSH was increased by a subMIC of both antibiotics in bacterial adherence to n-hexadecane assays. Conversely, antibiotic inhibition of biofilm formation was not observed. All strains enhanced biofilm formation on glass after treatment with ERY, while only strain 241 increased glass adherence after cultivation in the presence of PEN. Biofilm production on polystyrene surfaces was improved by &frac18; MIC of ERY. After growth in the presence of both antimicrobial agents, strains 241 and CDC-E8392 exhibited anionic surface charges with focal distribution. In conclusion, subMICs of PEN and ERY modified bacterial surface properties and enhanced not only biofilm formation but also cell-surface hydrophobicity. Antibiotic-induced biofilm formation may contribute to the inconsistent success of antimicrobial therapy for C. diphtheriae infections.
authors: Faculty of Pharmacy, Federal Institute of Education, Science and Technology of Rio de Janeiro, IFRJ, Rio de Janeiro RJ, Brazil.|Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: D L R
authors: DLR
authors: Gomes
authors: Department of Medical Microbiology, Institute of Microbiology, Rio de Janeiro Federal University, UFRJ, Rio de Janeiro RJ, Brazil.|Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: R S
authors: RS
authors: Peixoto
authors: Faculty of Pharmacy, Federal Institute of Education, Science and Technology of Rio de Janeiro, IFRJ, Rio de Janeiro RJ, Brazil.
authors: E A B
authors: EAB
authors: Barbosa
authors: Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: F
authors: F
authors: Napoleão
authors: Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: P S
authors: PS
authors: Sabbadini
authors: Department of Medical Microbiology, Institute of Microbiology, Rio de Janeiro Federal University, UFRJ, Rio de Janeiro RJ, Brazil.
authors: K R N
authors: KRN
authors: Dos Santos
authors: Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: A L
authors: AL
authors: Mattos-Guaraldi
authors: Laboratory of Diphtheria and Corynebacteria of Medical Relevance, Faculty of Medical Sciences, Rio de Janeiro State University, UERJ, Rio de Janeiro RJ, Brazil.
authors: R
authors: R
authors: Hirata
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects / Q000254:growth & development*; D003353:Corynebacterium diphtheriae / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology*; D005898:Glass; D057927:Hydrophobic and Hydrophilic Interactions; D008826:Microbial Sensitivity Tests; D046529:Microscopy, Electron, Transmission; D010406:Penicillins / Q000494:pharmacology*; D011137:Polystyrenes; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D011137:Polystyrenes; D004917:Erythromycin