Table 1. The antibiotic activity of clavaspirin, its analogue peptides and melittin, erythromycin, gentamicin, ampicillin and piperacidin.
| Microorganism strains | MIC (μM) | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Cla | CSP-1 | CSP-2 | CSP-3 | CSP-4 | Me | Er | Ge | Am | Pi | ||||||
| I | II | I | II | I | II | I | II | I | II | ||||||
| Gram (–) | |||||||||||||||
| E. coli | 2 | 64 | 4 | 8 | 2 | 4 | 2 | 4 | 2 | 4 | 2 | - | - | - | - |
| P. aeruginosa | 32 | >64 | 32 | 32 | 32 | 16 | 32 | 32 | 32 | 32 | 2 | - | - | - | - |
| L. monocytogenes | 16 | 64 | 16 | 64 | 8 | 4 | 16 | 8 | 4 | 4 | 2 | - | - | - | - |
| Gram (+) | |||||||||||||||
| B. subtilis | 16 | 64 | 16 | 64 | 4 | 4 | 8 | 16 | 4 | 4 | 2 | - | - | - | - |
| S. epidermidis | 4 | 32 | 4 | 16 | 4 | 32 | 4 | 8 | 4 | 8 | 2 | - | - | - | - |
| S. aureus | 16 | 64 | 16 | 64 | 8 | 16 | 8 | 8 | 8 | 8 | 2 | - | - | - | - |
| S. typhimurium | 32 | 64 | 32 | 64 | 64 | 4 | 64 | 4 | 64 | 4 | 2 | - | - | - | - |
| P. vulgaris | 8 | 64 | 8 | 64 | 4 | 8 | 4 | 8 | 4 | 8 | 2 | - | - | - | - |
| Resistant | |||||||||||||||
| E. coli CCARM1238 | - | - | - | - | - | - | - | - | - | 2 | 2 | - | - | >800 | >800 |
| P. aeruginosa 3543 | - | - | - | - | - | - | - | - | - | 4 | 2 | - | - | >800 | >800 |
| P. aeruginosa 3904 | - | - | - | - | - | - | - | - | - | 2 | 2 | - | - | >800 | >800 |
| P. aeruginosa 3547 | - | - | - | - | - | - | - | - | - | 4 | 2 | - | - | 400 | 200 |
| P. aeruginosa 4007 | - | - | - | - | - | - | - | - | - | 2 | 2 | - | - | >800 | >800 |
| S. aureus 3126 | - | - | - | - | - | - | - | - | - | 8 | 2 | 128 | 32 | - | - |
| S. aureus 0027 | - | - | - | - | - | - | - | - | - | 8 | 2 | >256 | 64 | - | - |
| S. aureus 5157 | - | - | - | - | - | - | - | - | - | 8 | 2 | 16 | 16 | - | - |
| S. aureus 1635 | - | - | - | - | - | - | - | - | - | 8 | 2 | >256 | >256 | - | - |
| S. aureus 4761 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | 32 | - | - |
| S. aureus 5159 | - | - | - | - | - | - | - | - | - | 8 | 8 | 16 | 16 | - | - |
| S. aureus 3359 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | 64 | - | - |
| S. aureus 2122 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | 128 | - | - |
| S. aureus 1630 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | 64 | - | - |
| S. aureus 1870 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | 16 | - | - |
| S. aureus 3511 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | >256 | - | - |
| S. aureus 5156 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | >256 | - | - |
| S. aureus 3518 | - | - | - | - | - | - | - | - | - | 8 | 4 | >256 | >256 | - | - |
Minimum inhibitory concentrations (MIC) were determined in 10 mM sodium phosphate buffer (I, pH 5.5; and II, pH 7.4) containing 10% Luria broth (LB). Drug-resistant Pseudomonas aeruginosa and Staphylococcus aureus bacteria were isolated from hospitalized otitis media patients (Chonnam National University’s hospital, Korea). This strain (with CCARM number) was obtained from the Culture Collection of Antimicrobial Resistant Microbes in Korea. Cla, Me, Er, Ge, AM and Pi are Clavaspirin, Melittin, erythromycin, gentamicin, ampicillin and piperacidin, respectively. (–) is not determined.