Table 4.
. Minimum inhibitory concentration (MIC, expressed as µg/mL) of selected antibiotics and activity of macedocin ST91KM (expressed as AU/mg protein) against mastitis-causing pathogens
| Macedocin ST91KM Activity | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MIC (µg/mL) of antibioticsa | ST91KMppt.c | ST91KMcond | |||||||||||||
| Organism | Strain | AMP | OXA | PEN | METb | EM | AU/mL Activity | AU/mg Protein | AU/mL Activity | AU/mg Protein | |||||
| S. agalactiae | RPSAG1 | 0.25 | S | 4.00 | R | 0.50 | I | 8.00 | R | 0.50 | I | 640 | 76.8 | 2560 | 204.8 |
| S. agalactiae | RPSAG2 | 0.25 | S | 4.00 | R | 0.25 | I | 16.00 | R | 0.25 | S | 1280 | 76.8 | 5120 | 204.8 |
| S. dysgalactiae | RPSD1 | 0.25 | S | 8.00 | R | 0.25 | I | 8.00 | R | 0.25 | S | 640 | 76.8 | 2560 | 204.8 |
| S. dysgalactiae | RPSD2 | 0.25 | S | 4.00 | R | 0.25 | I | 16.00 | R | 0.25 | S | 640 | 76.8 | 2560 | 204.8 |
| S. dysgalactiae | RPSD3 | 0.25 | S | 4.00 | R | 0.25 | I | 8.00 | R | 0.25 | S | 640 | 76.8 | 2560 | 204.8 |
| S. dysgalactiae | RPSD4 | 0.25 | S | 4.00 | R | 0.50 | I | 16.00 | R | 0.50 | I | 640 | 76.8 | 2560 | 204.8 |
| S. uberis | RPSU1 | 0.12 | S | 8.00 | R | 0.25 | I | 16.00 | R | 0.25 | S | 640 | 76.8 | 10240 | 204.8 |
| S. uberis | RPSU2 | 0.25 | S | 8.00 | R | 0.25 | I | 16.00 | R | 0.25 | S | 160 | 75.2 | 640 | 217.6 |
| S. uberis | EDSU1 | 0.12 | S | 8.00 | R | 0.25 | I | 32.00 | R | 0.25 | S | 640 | 76.8 | 5120 | 204.8 |
| S. uberis | EDSU2 | 0.25 | S | 8.00 | R | 1.00 | I | 16.00 | R | 0.50 | I | 160 | 75.2 | 1280 | 217.6 |
| S. aureus | RPSA1 | 0.12 | S | 8.00 | R | 0.50 | R | 16.00 | R | 0.50 | S | 640 | 76.8 | 1280 | 217.6 |
| S. aureus | RPSA2 | 0.25 | S | 8.00 | R | 0.50 | R | 16.00 | R | 0.50 | S | 640 | 76.8 | 1280 | 217.6 |
| S. aureus | EDSA | 0.25 | S | 4.00 | R | 0.50 | R | 16.00 | R | 0.50 | S | 0 | 0 | 0 | 0 |
| S. aureus | EDSA0267 | 0.25 | S | 8.00 | R | 8.00 | R | 16.00 | R | 0.25 | S | 640 | 76.8 | 1280 | 217.6 |
| S. aureus | EDSA0269 | 0.12 | S | 8.00 | R | 0.50 | R | 16.00 | R | 0.50 | S | 640 | 76.8 | 1280 | 217.6 |
| S. epidermidis | RPSE1 | 0.25 | S | 16.00 | R | 0.50 | R | 16.00 | R | 0.25 | S | 2560 | 76.8 | 10240 | 204.8 |
| E. coli | RPEC1 | 1.00 | S | >32 | (R) | 32.00 | (R) | >32.00 | (R) | >32 | (R) | 0 | 0 | 0 | 0 |
| E. coli | RPEC2 | 2.00 | S | >32 | (R) | 32.00 | (R) | >32.00 | (R) | >32 | (R) | 0 | 0 | 0 | 0 |
ampicillin (AMP), oxacillin (OX), penicillin G (PEN), methicillin (MET), erythromycin (EM); sensitive (S), intermediate (I), resistant (R);
MET interpretative data based on OX
No veterinary-specific interpretative criteria available for E.coli for OX, PEN, MET and EM, breakpoint interpretation is thus given in parentheses.
macedocin ST91KM precipitated in 60% saturated ammonium sulphate,
macedocin ST91KM precipitated in 60% saturated ammonium sulphate, eluted with 40% (v/v) isopropanol, in 25mM ammonium acetate buffer (pH 6.5). Fractions of 1mL were dried under vacuum at 50°C, reconstituted to final volume of 1mL with ammonium acetate buffer (pH 6.5)