The effect of recombinant human lactoferrin on growth and the antibiotic susceptibility of the cystic fibrosis pathogen Burkholderia cepacia complex when cultured planktonically or as biofilms.
OBJECTIVE
The cystic fibrosis (CF) pathogen Burkholderia cepacia complex (Bcc) is innately resistant to antibiotics and the development of effective therapeutic strategies to treat these infections is a major challenge. The objectives of this study were to investigate the effects of recombinant human lactoferrin (rHL) on planktonic and biofilm cultures of Bcc organisms and to establish whether lactoferrin alters the susceptibility of these cultures to a range of antibiotic therapies.


METHODS
Planktonic and biofilm cultures of strains representative of three species of Bcc, Burkholderia multivorans, Burkholderia cenocepacia and Burkholderia dolosa, were exposed to 0-900 mg/L lactoferrin over 0-48 h. Growth was determined using both spectrophotometric and plate counting methods. The ability of these strains to form and develop biofilms in vitro was also examined. Antimicrobial susceptibility in the presence/absence of lactoferrin was assessed using conventional MICs and a modified method was used to determine biofilm susceptibility to various antibiotics.


RESULTS
We found that physiological concentrations of lactoferrin inhibited the growth of both planktonic and biofilm cultures of Bcc in vitro. The addition of lactoferrin to rifampicin enhanced the antibiotic susceptibility of the Bcc strains when grown planktonically and as biofilms.


CONCLUSIONS
The present study demonstrates the growth inhibitory and antibiofilm activity of rHL against different species of Bcc. Furthermore, the enhanced susceptibility of both planktonic and biofilm cultures to rifampicin in the presence of lactoferrin offers the potential for novel uses of antibiotics in combination with lactoferrin to treat Bcc infections in CF patients.
Caraher
Emma M
EM
Centre of Microbial Host Interaction, Department of Science, Institute of Technology Tallaght (ITT-Dublin), Tallaght, Dublin 24, Ireland.
Gumulapurapu
Kiranmai
K
Taggart
Clifford C
CC
Murphy
Philip
P
McClean
Siobhán
S
Callaghan
Máire
M
D018441:Biofilms / Q000187:drug effects; D042602:Burkholderia cepacia complex / Q000187:drug effects* / Q000254:growth & development*; D015169:Colony Count, Microbial; D003550:Cystic Fibrosis / Q000382:microbiology*; D024881:Drug Resistance, Bacterial / Q000187:drug effects; D007781:Lactoferrin / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D011994:Recombinant Proteins / Q000494:pharmacology
D011994:Recombinant Proteins; D007781:Lactoferrin