Glycopeptide-resistant enterococci

After 5 days administration of quinupristin + dalfopristin 7.5 mg/kg infused over 1 hour bd, the fecal microflora in 20 healthy volunteers increased significantly during treatment and returned within 12 weeks to baseUne concentrations after the end of treatment. There were anerobes and enterococci resistant to erythromycin or to quinupristin - - dalfopristin, but glycopeptide-resistant enterococci did not emerge (22). 

Antimicrobial resistance of major consequence may be detected, e.g., the test is very useful in detecting glycopeptide-resistant enterococci and glycopeptide-intermediate Staphylococcus aureus and slow-growing pathogens such as Mycobacterium tuberculosis. Furthermore, it can be used for detecting extended spectrum P-lactamases. In conclusion, the E-test is a simple, accurate and reliable method to determine the MIC for a wide spectrum of infectious agents [33, 34]. 

Messer J, Reynolds P. Modified peptidoglycan precursois produced by glycopeptide-resistant enterococci. FEMS Microbiol Lett 1992 1992 195-200. 

Arthur M., Reynolds P. Courvalin P. (1996) Glycopeptide resistance in enterococci. Trends Microbiol, 4,401-407. 

Acquired resistance to the glycopeptides is transposon-mediated and has so far been largely confined to the enterococci. This has been a problem clinically because many of these strains have been resistant to all other antibiotics and were thus effectively untreatable. Fortunately, the enterococci are not particularly pathogenic and infections have been confined largely to seriously ill, long-term hospital patients. Two types of acquired glycopeptide resistance have been described (Woodford et al. 1995). The VanA phenotype is resistant to vancomycin and teicoplanin, whereas VanB is resistant... 

Nicas, T.I. et al. Semisynthetic glycopeptide antibiotics derived from LY264826 active against vancomycin-resistant enterococci, Antimicrob. Agents Chemother., 40, 2194, 1996. 

Zirakzadeh A, Patel R. Epidemiology and mechanisms of glycopeptide resistance in enterococci. Curr Opin Infect Dis. 2005 18 507-512. 

M Arthur, P Courvalin. Genetics and mechanism of glycopeptide resistance in enterococci. Antimicrob Agents Chemother 37 1563-1571, 1993. 

Vancomycin-resistant enterococci and staphylococci (see later) are important pathogens. The latter contain rather thicker cell walls than vancomycin-sensitive S. aureus [153] and in the absence of a fuller explanation at present, it is tempting to speculate that the cell wall in the resistant organisms could reduce uptake of this glycopeptide antibiotic. 

Over the past decade the emergence of resistant enterococci and S. aureus strains has been observed in clinics. Already, nowadays, the increase of glycopeptide-resistant... 

In a study of antibiotic resistance in enterococci from raw meat, there was a high prevalence of glycopeptide-resistant strains (49). Resistance to vancomycin was significantly associated with resistance to teicoplanin, erythromycin, tetracycline, and chloramphenicol. 

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). 

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