Vancomycin-resistant Enterococcus faecalis

The combined synergistic effects of cyclo(Leu-Pro) and cyclo(Phe-Pro) were effective against five vancomycin-resistant enterococci (VRE) strains Enterococcus faecium (K-99-38), E. faecalis (K-99-17), E. faecalis (K-99-258), E. faecium (K-01-312), and E. faecalis (K-01-511) with MIC values of 0.25—1 mgl . It also showed activity against E. coli, Staphylococcus aureus. Micrococcus luteus, Candida albicans, and Cryptococcus neoformans with MIC values of 0.25—0.5 mg 1. This combination also showed mutagenic activity against Salmonella typhimurium TA98 and TAIOO strains in a Salmonella mutation assay. ... 

Noble W.C., Z. Virani, and R.G. Cree (1992). Co-transfer of vancomycin and other resistance genes from Enterococcus faecalis NCTC to Staphylococcus aureus. FEMS Microbiology Letters 72 195-198. 

Evers, S. Courvalin, P. Regulation of VanB-type vancomycin resistance gene expression by the VanS(B)-VanR (B) two-component regulatory system in Enterococcus faecalis V583. J. Bacteriol., 178, 1301-1309 (1996)... 

Daptomycin has proven efficacy in a number of in vivo animal models, including soft tissue infections by MRSA, bacteraemia caused by S. aureus or vancomycin-resistant enterococci (VRE), Enterococcus faecalis pyelonephritis, MRSA osteomyelitis, MRSA and Bacillus anthracis pulmonary infections, Gram-positive endocarditis, Clostridium difficile colitis and S. pneumoniae and S. aureus meningitis.9,64 66... 

The activity of daptomycin against both vancomycin-sensitive and vancomycin-resistant Enterococcus faecalis was greater than that of quinupristin + dalfopristin (5). Daptomycin was as active as quinupristin + dalfopristin but more active than linezolid. At concentrations four times the MIC, daptomycin and vancomycin achieved 99.9% killing of methicillin-resistant Staphylococcus aureus after 8 hours, which was greater than the killing seen with linezolid and quinupristin + dalfopristin. However, the antibacterial activity of daptomycin strongly depended on the calcium concentration of the medium. 

A 53-year-old white woman with liver cirrhosis took vancomycin (1 g bd) for sepsis due to methicillin-resistant S. aureus and a catheter-associated infection due to Enterococcus faecalis, developed oral and vaginal mucositis and conjunctivitis followed by a macu-lopapular rash (69). The diagnosis was confirmed by skin biopsy. Vancomycin was replaced by teicoplanin and corticosteroids the symptoms disappeared within 7 days. 

Glycopeptide resistance in a cluster of three clinical isolates of vancomycin-resistant Enterococcus faecium was due to vanD, which was located on the chromosome and was not transferable to other enterococci These isolates were indistinguishable but differed from the strain in which vanD-mediated resistance has been reported previously (102). A type of acquired glycopeptide resistance, named vanE, has been characterized in E. faecalis BM 4405. It results in low-level resistance of vancomycin but susceptibility to teico-planin (103). Defects in penicillin-binding protein 4 result in a distorted peptidoglycan composition of the cell of vancomycin-resistant and teicoplanin-resistant laboratory mutants of S. aureus and are suggested to be part of the mechanism of glycopeptide resistance in these microbes (104). 

While many natural products have been tested against hundreds of different strains of bacteria, the most common bacteria used in susceptibility tests include Bacillus cereus, Bacillus subtillis, Chlamydia pneumonia, Enterococcus faecalis, Escherichia coli, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus (MRSA), Streptococcus pneumoniae, Klebsiella pneumoniae, vancomycin-resistant Enterococcus (VRE), Pseudomonas aeruginosa and Helicobacter pylori [18, 19], As the amount of published data describing the in vitro, in vivo and clinical antibacterial activities of natural products is so vast it could easily fill a book (or two), this review focuses only on natural products for which there is in vitro, in vivo and some clinical antibacterial data, as well as a plausible mechanism of action. 

Centeno JA, Menendez S, Rodriguez-Otero JL (1996) Main microbial flora present as natural starters in Cebreiro raw cow s-milk cheese (northwest Spain). Int J Food Microbiol 33 307-313 Centeno JA, Menendez S, Hermida M, Rodriguez-Otero JL (1999) Effects of the addition of Enterococcus faecalis in Cebreiro cheese manufacture. Int J Food Microbiol 48 97-111 Cetinkaya Y, Falk P, Mayhall CG (2000) Vancomycin-resistant enterococci. Clin Microbiol Rev 13 686-707... 

Klepser, M. E. et ah. Comparison of hactericidal activities of intermittent and continuous infusion dosing of vancomycin against methiciUin-resistant Staphylococcus aureus and Enterococcus faecalis. Pharmacotherapy, 18(5) 1069-1074, 1998. 

Like the battle against viruses, the war to stop bacterial and parasitic infections has reached the critical stage, with multidrug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecalis (VRE), killing thousands of people annually in the United States [196]. Likewise, tuberculosis (TB) has killed about 1 billion people worldwide over the past two centuries. Some 3.5 milUon people in India are currently infected with TB [197]. 

Evers S, Reynolds P, Courvalin P. Sequence of the vanB and ddl genes encoding D-abnine D lactate and D-alanine D-alanine ligases in vancomycin-resistant Enterococcus faecalis V583. Gene 1994 140 97-102. 

Nicas Tl. Wu CYE, Hobbs JN]r, Allen NE. Characterization of vancomycin resistance in Emerococcus faecium and Enterococcus faecalis. Antimicrob Agents Chemother 1989 33 1121-1124. 

Handwerger 5, Pucci M], Volk KJ, Liu, Lee MS. The cytoplasmic peptidoglycan precursor of vancomycin-resistant Enterococcus faecalis terminates in lactate. J Bacteriol 1992 174 5982-5984. 

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