JAC Advance Access originally published online on February 29, 2008
Journal of Antimicrobial Chemotherapy 2008 61(5):1092-1098; doi:10.1093/jac/dkn074
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Original research |
Antimicrobial activity of omiganan pentahydrochloride tested against contemporary bacterial pathogens commonly responsible for catheter-associated infections
1 JMI Laboratories, North Liberty, IA 52317, USA 2 Universidade Federal de Sao Paulo, Sao Paulo, Brazil 3 Tufts University School of Medicine, Boston, MA, USA
Received 14 November 2007; returned 29 December 2007; revised 17 January 2008; accepted 31 January 2008
* Corresponding author. Tel: +1-319-665-3370; Fax: +1-319-655-3371; E-mail: thomas-fritsche{at}jmilabs.com
Objectives: Omiganan pentahydrochloride is a cidal cationic peptide with a broad antimicrobial spectrum, including yeast, currently in development as a topical agent for the prevention of catheter-associated infections. We evaluated the spectrum and potency of omiganan against pathogens commonly associated with such infections.
Methods: A recent (2005–06) collection of bacterial isolates originating from patients with bloodstream, respiratory tract, and skin and skin structure infections in US medical centres was evaluated by reference broth microdilution methods against omiganan and comparator agents.
Results: All tested Gram-positive (390) and -negative (167) isolates were inhibited by 
128 and 1024 mg/L, respectively, of omiganan. The agent was the most active against coagulase-negative staphylococci (range 1–8 mg/L; MIC50/90, 4 mg/L) and inhibited all Staphylococcus aureus at 32 mg/L (MIC50/90, 16 mg/L). Omiganan was 16-fold more active against Enterococcus faecium than Enterococcus faecalis (MIC50/90 results, 4/8 versus 64/128 mg/L, respectively). MIC ranges and MIC50 potencies were unaffected by methicillin resistance in staphylococci, vancomycin resistance in enterococci, and penicillin resistance in streptococci. Omiganan potency was also unaffected by extended-spectrum β-lactamase (ESBL) production in Escherichia coli when compared with wild-type strains (MIC50 values 32 mg/L), although a 4-fold increase was noted among ESBL-positive Klebsiella spp. (128 versus 32 mg/L, respectively). Wild-type Enterobacter spp. displayed higher omiganan MIC50/90 results (64/512 mg/L) compared with AmpC-hyperproducing strains (32/64 mg/L). Carbapenem-susceptible and -resistant P. aeruginosa strains exhibited omiganan MIC50/90 values of 128/256 mg/L.
Conclusions: At a 1% (10 000 mg/L) topical gel formulation, omiganan can be expected to inhibit all clinically relevant bacterial species producing catheter-associated infections (all MIC values, 1024 mg/L), including those with antimicrobial-resistant phenotypes.
Keywords: cationic peptides , topical antimicrobials , resistance , bloodstream infections