In-vitro postantibiotic effects of miocamycin and erythromycin on gram-positive cocci.
The capability of miocamycin to induce a postantibiotic effect (PAE) on a Group A Streptococcus beta-haemolyticus clinical isolate and on Staphylococcus aureus ATCC 29213 has been studied. Erythromycin was chosen as a reference molecule. The exposure time to antibiotics was 90 min. The removal technique of the antibiotic agents consisted of a 1:200 dilution in cultural broth. Miocamycin displayed a PAE of 2 h 30 min in relation to the minimum inhibitory concentration (MIC) of Streptococcus and a PAE of 2 h 30 min in relation to the MIC of Staphylococcus. The PAE value lasting longer than the others was of 5 h 40 min towards Streptococcus and of 4 h 18 min towards Staphylococcus at a concentration eightfold the MIC. Erythromycin showed a PAE of 1 h 36 min in relation to the MIC of Streptococcus and a PAE of 1 h 30 min in relation to the MIC of Staphylococcus. The PAE value lasting longer than the others was of 3 h 15 min against Streptococcus and of 2 h 30 min against Staphylococcus at a concentration eightfold the MIC. In some cases a PAE was observed in relation to subinhibitory concentrations (1/2 MIC). Miocamycin therefore proved to possess a more evident capability to induce a PAE against the clinical isolate of Group A Streptococcus beta-haemolyticus and on Staphylococcus aureus ATCC 29213 than did erythromycin.
Varotto
F
F
Clinical Research Laboratory, Istituti Clinici di Perfezionamento, Milan, Italy.
Garlaschi
M L
ML
Garlaschi
M C
MC
Falchi
M
M
Scaglione
F
F
Cattaneo
G
G
De Luca
M
M
Fraschini
F
F
D000328:Adult; D015169:Colony Count, Microbial; D004917:Erythromycin / Q000494:pharmacology*; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D006801:Humans; D015644:Miocamycin / Q000494:pharmacology*; D013211:Staphylococcus aureus / Q000187:drug effects / Q000254:growth & development*; D013291:Streptococcus / Q000187:drug effects / Q000254:growth & development*; D013997:Time Factors
D015644:Miocamycin; D004917:Erythromycin