title: Ultrastructural and cytochemical study of cell wall modification by lactoferrin, lactoferricin and penicillin G against Staphylococcus aureus.
abstract: To investigate the effect of lactoferrin or lactoferricin with or without penicillin G, light and transmission electron microscopy were performed on thin sections of two Staphylococcus aureus strains. Lactoferrin affected the ultrastructure of S. aureus and groups of undivided cells were observed after lactoferrin treatment with or without penicillin G. These results suggest that lactoferrin can affect staphylococcal cell separation and therefore prevent dissemination of daughter cells from spreading infection. After treatment with lactoferrin, S. aureus cells were less covered (P<0.05) with wheatgerm agglutinin labelled with gold, thus suggesting that lactoferrin affected the synthesis of peptidoglycan and/or the binding to N-acetyl-beta-D-glucosamine. Lactoferricin with or without penicillin G induced the lysis of many bacteria, formation of mesosomal structures and modifications of cell wall. Lactating female CD-1 mice were infected by intramammary delivery of a penicillin-resistant S. aureus strain and were then randomly assigned to treatments according to a 2 x 2 factorial design. Electron microscopy examination showed that 2 days of systemic treatments with lactoferrin affected the morphology and aggregation of S. aureus. In conclusion, lactoferrin and lactoferricin affect S. aureus morphology which may facilitate its killing by penicillin G.
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Lennoxville, QC J1M 1Z3, Canada.
authors.forename: Moussa Sory
authors.initials: MS
authors.lastname: Diarra
authors.forename: Pierre
authors.initials: P
authors.lastname: Lacasse
authors.forename: Elaine
authors.initials: E
authors.lastname: Deschênes
authors.forename: Gilles
authors.initials: G
authors.lastname: Grondin
authors.forename: Catherine
authors.initials: C
authors.lastname: Paradis-Bleau
authors.forename: Denis
authors.initials: D
authors.lastname: Petitclerc
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000032:analysis; D002473:Cell Wall / Q000737:chemistry / Q000187:drug effects / Q000648:ultrastructure; D004357:Drug Synergism; D005260:Female; D006651:Histocytochemistry; D007781:Lactoferrin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051379:Mice; D008854:Microscopy, Electron; D010400:Penicillin G / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects* / Q000648:ultrastructure
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C082171:lactoferricin B; D007781:Lactoferrin; D010400:Penicillin G