The antimicrobial effect of heparin on common respiratory pathogens.
OBJECTIVE
The mucolytic, anticoagulative, anti-inflammatory and neo-angiogenic properties of inhaled heparin may benefit patients with burns and cystic fibrosis. We assessed the antibacterial effects of unfractionated heparin.


METHODS
Stored clinical isolates of Acinetobacter baumannii (n =4), Candida albicans (n = 5), Haemophilus influenzae (n =5), Klebsiella pneumoniae (n =4), methicillin-resistant Staphylococcus aureus (n=3), Pseudomonas aeruginosa (n = 2), and Streptococcus pneumoniae (n = 7) were subcultured on horse blood agar, incubated at 35 degrees C overnight, then inoculated into trypticase soy broth to a density of 1 McFarland standard. Dilutions of unfractionated heparin (containing 250- 7500 U) and 100 microL of the 1.0 McFarland standard broth were incubated at 35 degrees C overnight in microtitre plates and then subcultured on horse blood agar using 1 microL standard loops. Colonies (representing viable organisms) were counted.


RESULTS
Heparin produced dose-dependent growth inhibition of three of seven S. pneumoniae isolates (complete inhibition at 2500U dose per 200 microL) and one of five H. influenzae isolates (complete inhibition at 7500 U dose per 200 microL), but no inhibition of other isolates.


CONCLUSIONS
Unfractionated heparin is unlikely to have antibacterial effects because of its unpredictable inhibition of growth of common respiratory pathogens.
Zappala
Christopher
C
Department of Intensive Care Medicine, Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia.
Chandan
Snehal
S
George
Narelle
N
Faoagali
Joan
J
Boots
Robert J
RJ
D000925:Anticoagulants / Q000494:pharmacology*; D015169:Colony Count, Microbial; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification; D006493:Heparin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification
D000925:Anticoagulants; D006493:Heparin