| 摘要 |
<p>A KA-6643-series antibiotic comprising at least one substance represented by any of the following formulae, or a salt or ester thereof: …<CHEM>… is effectively useful as an antibacterial and beta -lactamase inhibiting agent and can be produced by culturing a strain belonging to the genus Streptomyces which can produce the KA-6643 substances, and isolating the antibiotic from the culture broth.</p> |
