In vitro Activity of A-16686, a New Glycopeptide

Abstract

A-16686 is a novel glycopeptide antibiotic derived from Actinoplanes. A-16686 inhibited hemolytic streptococci groups A, B, C, F, and G at concentrations of ≤ 0.06 to 0.5 μg/ml, with 90% inhibited by 0.5μg/ml, including erythromycin-resistant isolates. S. bovis, various viridans groups streptococci, S. mitis, S. mutans, and S. sanguis were inhibited by ≤ 1 μg/ml, and MICs of S.faecalis and S.faecium were 0.5–2 μg/ml. Most staphylococci, including methicillin-resistant strains, were inhibited by 1 or 2 μg/ml. A-16686 was bactericidal with minimal difference between MIC and MBC for gram-positive species. A-16686 did not inhibit Enterobacteriaceae or Pseudomonas.

In vitro activities of ramoplanin and four glycopeptide antibiotics against clinical isolates of Clostridium difficile

“…The use of glycopeptides as topical intestinal agents could lead to an even greater risk that resistant enterococci will develop and possibly spread, even though it must be pointed out that vancomycin-resistant enterococcal strains are not always cross-resistant to teicoplanin and appear to be highly susceptible to teicoplanin analogs and other newly synthesized glycopeptides (24). Of great potential interest is our finding of the excellent activity of ramoplanin against C. difficile, which confirms and extends preliminary results of previous studies (19)(20)(21). In fact, ramoplanin appears to be a very good candidate as a first-line therapeutic option for the treatment of C. difficileassociated disease, particularly in view of possible limitations of the oral use of glycopeptides which could arise from the emergence of resistant enterococci.…”

Ramoplanin: A Lipoglycodepsipeptide Antibiotic

“…The in vitro activity of ramoplanin is predominantly against gram-positive aerobic and anaerobic bacteria. 3,5,17–22 Excellent activity has been documented against Streptococcus spp., Staphylococcus spp., and Enterococcus spp., along with antibiotic-resistant strains of these gram-positive pathogens. 21–23 Ramoplanin has demonstrated in vitro activity against gram-positive anaerobic bacteria such as C. difficile , other Clostridium spp., Eubacterium spp., Lactobacillus spp., Peptostreptococcus spp., Propionibacterium spp., and Prevotella spp.…”

“…In vitro antimicrobial comparisons were completed with ramoplanin, teicoplanin, linezolid, quinupristin/dalfopristin, and vancomycin against gram-positive pathogens (Table 1). 3,5,17–31 Ramoplanin has established activity against Streptococcus spp. that is comparable to or exceeds that of teicoplanin and vancomycin.…”

Chemistry and biology of the ramoplanin family of peptide antibiotics

“…We will therefore briefly summarize these results. Ramoplanin is active against a wide variety of Gram‐positive bacteria16, 17 including enterococci,18–24 staphylococci,17, 18, 24–32 bacilli,20 streptococci,24, 27, 33, 34 Listeria monocytogenes, 20 and Gram‐positive anaerobes such as Clostridium difficile. 23, 31, 33, 35–37…”