E.faecium

Mechanism of Resistance. Recendy, resistance to high levels of dalbaheptides has been described in both E.faecium and E.faecalis (111). 

If the isolate is determined to be vancomycin-resistant, it is most important to know the exact species because some of the treatment options, such as quinupristin/dalfopristin, are not active against E. faecalis. Currently, the treatment options for vancomycin-resistant enterococci (VRE) are not well established by clinical studies or patient experience. The treatment recommendations for vancomycin-resistant E. faecium include linezolid or quinupristin/dalfopristin for a minimum of 8 weeks. However, newer agents, such as daptomycin, may provide another option for treatment for either enterococci species (E. faecium and E. faecalis). Additionally, guidelines suggest the use of imipenem-cilistatin plus ampicillin or ceftriaxone plus ampicillin for the treatment of E. faecalis with a minimum of 8 weeks of therapy. Consultation with an infectious diseases specialist is recommended. 

More recently, work of Scharek et al. (2005) has shown that supplementing the feed of pregnant sows and piglets with a probiotic strain of E. faecium produces an immune-stimulatory effect. Also, Davis et al. (2006) described... 

Vancomycin-resistant enterococci, particularly E. faecium, are becoming more common. 

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. ... 

Vancomycin-resistant Enterococcus faecium infections For the treatment of vancomycin-resistant E. faecium infections, including cases with concurrent bacteremia. 

E. faecium Source %Susceptibility to Quinupristin-Dalfopristin %Resistance Genes ... 

Quinupristin-dalfopristin is approved for treatment of infections caused by staphylococci or by vancomycin-resistant strains of E faecium, but not E faecalis, which is intrinsically resistant probably because of an efflux-type resistance mechanism. The principal toxicities are infusion-related events, such as pain at the infusion site, and an arthralgia-myalgia syndrome. 

In another study published in the same year, researchers at the CDC found that half of 407 supermarket chickens bought from 26 stores in four states—Georgia, Maryland, Minnesota, and Oregon—carried the sometimes fatal germ E. faecium in a form resistant to Synercid , one of the few drugs of last resort against the infection. 

An association between antibiotic resistance and chlorhexidine and QAC resistance in Providencia stuartii and Proteus has been observed, but no evidence of a plasmid link obtained [25, 73, 287,288]. Chlorhexidine hypersensitivity has been noted in ciprofloxacin-resistant variants of Ps. aeruginosa [289] and vancomycin- and gentamicin-resistant strains of E. faecium retained sensitivity to the /usbiguanide [289, 290] and to other biocides [270-272], Anderson et al. [272] studied the inactivation kinetics of VRE and vancomycin-sensitive enterococci (VSE) exposed to environmental disinfectants at concentrations well below (extended dilutions) the recommended use-dilutions and found no differences in susceptibility of VRE and VSE. This type of approach is much more relevant than the widespread usage of MICs to measure responses to biocides. 

A resistance gene, named linB, which encodes a lin-cosamide nucleotidyltransferase catalysing the adenyla-tion of the hydroxyl group in position 3 of the molecules of lincomycin and clindamycin has been characterized in a clinical isolate of Enterococcus faecium (53). Expression of linB was also observed in Escherichia coli and S. aureus, and the spread of this gene in other clinical isolates of E. faecium has been suggested. 

Among strains of Enterococcus faecium, resistance against tylosin was mainly detected in strains from poultry, but also in some strains from pork. Among strains of E. faecium and Enterococcus faecalis isolated from pigs and poultry in Denmark, resistance to tylosin was often observed among isolates from places in which these antimicrobials had been widely used, but rarely among isolates from places in which their use had been limited (83). 

In 25 liver transplant recipients who received intravenous quinupristin -I- dalfopristin 7.5 mg/kg 8-hourly for vancomycin-resistant E. faecium infection, hyperbiUmbinemia developed, but there was no evidence of drug-specific histological injury (35). 

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