Inhibition of mastitic bacteria by bovine milk apo-lactoferrin evaluated by in vitro microassay of bacterial growth.
An in vitro microassay was developed to evaluate antimicrobial properties of bovine apo-lactoferrin. The growth of coliform, staphylococcal, and streptococcal bacterial strains in a defined synthetic medium was inhibited by bovine apo-lactoferrin (.5 to 30.0 mg/ml). Addition of iron-saturated lactoferrin to the synthetic medium did not inhibit growth of test strains. Inhibition by apo-lactoferrin was greater for coliform than Gram-positive strains for all concentrations of apo-lactoferrin evaluated. No concentration of apo-lactoferrin proved bactericidal for either coliform or Gram-positive strains. Inhibition of two coliform strains by apo-lactoferrin (10 mg/ml) was abolished by addition of ferric iron to the assay system, indicating an iron-dependent nature of apo-lactoferrin induced inhibition of bacteria. Bicarbonate supplementation of the growth system containing apo-lactoferrin (1 mg/ml) increased inhibition of three coliform strains by apo-lactoferrin. Addition of increasing concentrations of citrate (2.0 mg/ml) to an assay system containing apo-lactoferrin (5 mg/ml) resulted in a concomitant reduction of growth inhibition of three coliform strains. These data indicate a potential relationship between the molar ratio of citrate to lactoferrin of the lacteal secretion and its capacity to inhibit coliform strains associated with mastitis.
D000818:Animals; D001059:Apoproteins / Q000494:pharmacology*; D001639:Bicarbonates / Q000494:pharmacology; D002417:Cattle; D002951:Citrates / Q000494:pharmacology; D019343:Citric Acid; D003470:Culture Media; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D005260:Female; D007501:Iron / Q000494:pharmacology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000254:growth & development; D007781:Lactoferrin / Q000494:pharmacology*; D007782:Lactoglobulins / Q000494:pharmacology*; D008414:Mastitis, Bovine / Q000382:microbiology*; D017693:Sodium Bicarbonate; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development; D013291:Streptococcus / Q000187:drug effects* / Q000254:growth & development
D001059:Apoproteins; D001639:Bicarbonates; D002951:Citrates; D003470:Culture Media; D007782:Lactoglobulins; C039223:apolactoferrin; D019343:Citric Acid; D017693:Sodium Bicarbonate; D007501:Iron; D007781:Lactoferrin