title: Biofilm formation by Streptococcus pneumoniae strains and effects of human serum albumin, ibuprofen, N-acetyl-l-cysteine, amoxicillin, erythromycin, and levofloxacin.
abstract: Streptococcus pneumoniae ability to produce biofilms may induce persistent infections and difficulties for eradication in vivo. We investigated the ability of 11 pneumococcal strains (serotypes 3, 6B, 9V, 19F, and 23F) to form biofilms on polystyrene plates at 16 and 24 h. The extent of biofilm was greater at 24 h in 10 strains, being the highest magnitude for serotype 3 strains. Human serum albumin at 25,000 microg/mL and ibuprofen at 128 microg/mL significantly reduced biofilm formation in 7 and 5 strains, respectively. Amoxicillin, erythromycin, and levofloxacin at supra-MIC concentrations were very active against planktonic cells of 3 selected strains but lower on biofilm-associated organisms in 2 strains and null against the third. Although N-acetyl-l-cysteine had very little activity against both planktonic and biofilm-forming organisms, when combined with the 3 antibiotics, a slightly enhanced activity against biofilm-embedded organisms in 1 strain and combined with amoxicillin in another one was observed.
authors.affiliation: Department in Medical Microbiology and Antimicrobial Chemotherapy, Fundación Jiménez Díaz-Capio, 28040 Madrid, Spain. gdp_marugan@yahoo.es
authors.forename: Gema
authors.initials: G
authors.lastname: del Prado
authors.forename: Vicente
authors.initials: V
authors.lastname: Ruiz
authors.forename: Plinio
authors.initials: P
authors.lastname: Naves
authors.forename: Violeta
authors.initials: V
authors.lastname: Rodríguez-Cerrato
authors.forename: Francisco
authors.initials: F
authors.lastname: Soriano
authors.forename: María
authors.initials: M
authors.lastname: del Carmen Ponte
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology; D000658:Amoxicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development*; D004917:Erythromycin / Q000494:pharmacology; D006801:Humans; D007052:Ibuprofen / Q000494:pharmacology; D064704:Levofloxacin; D015242:Ofloxacin / Q000494:pharmacology; D012709:Serum Albumin / Q000378:metabolism*; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology*
chemical_list: D000900:Anti-Bacterial Agents; D012709:Serum Albumin; D004917:Erythromycin; D064704:Levofloxacin; D000658:Amoxicillin; D015242:Ofloxacin; D007052:Ibuprofen; D000111:Acetylcysteine