Enterococcus methicillin-resistant

Infections acquired from an external source are referred to as exogenous infections. These infections may occur as a result of human-to-human transmission, contact with exogenous bacterial populations in the environment, and animal contact. Resistant pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus spp. 

Enterococcus spp. 50% resistance to methicillin Resistance to vancomycin greater... 

Linezohd (Zyvox) is an oxazolidinone, a tive-membered heterocychc ring that forms the core of the hnezohd structure. The approval of hnezohd by the FDA in 2000 marked the first new structural class of antibacterial introduced into medical practice in the United States in 40 years. It is notable for its activity against methicillin-resistant Staph aureus, MRSA, and vancomycin-resistant Enterococcus faecium, VRE. It is bacteriostatic rather than bactericidal but finds significant use in patients with an intact immune system. Like several other classes of antibacterials, linezolid is an inhibitor of protein synthesis. It interacts specifically with the RNA component of a bacterial ribosome subunit to prevent initiation of protein synthesis. 

An additional mechanism of antibiotic resistance involves an alteration of PBPs. Resistant bacteria, usually gram-positive organisms, produce PBPs with low affinity for p-lactam antibiotics. The development of mutations of bacterial PBPs is involved in the mechanism for p-lactam resistance in Streptococcus pneumoniae. Enterococcus faecium, and methicillin-resistant S. aureus (MRS A). 

Most appropriate use is when vancomycin-resistant Enterococcus faecium infection is documented or strongly suspected, or for oral therapy of methicillin-resistant Staphylococcus aureus infection... 

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. 

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. 

Mupirocin (Fig. 10.16C) is the main fermentation product obtained from Ps. fluorescens. Other pseudomonic acids (B, C and D) are also produced. Mupirocin is active predominantly against staphylococci and most streptococci, but Enterococcus faecalis and Gram-negative bacilli are resistant. There is also evidence of plasmid-mediated mupirocin resistance in some clinical isolates of Staph, aureus. Mupirocin is employed topically in eradicating nasal and skin carriage of staphylococci, including methicillin-resistant Staph, aureus (MRSA) colonization. 

ISPD International Society of Peritoneal Dialysis MRSA methicillin-resistant Staphylococcus aureus MRSE methicillin-resistant enterococcus NKF-K/DOQl National Kidney Foundation Kidney Disease Outcomes Quahtative Initiative PAN polyacrylonitrile PMMA polymethylmethacrylate PS polysulfone URR urea reduction ratio USRDS United States Renal Data System VRE vancomycin-resistant enterococcus WBC white blood cell (count)... 

TABLE 4. Antibacterial activity of gold(I) complexes against the problem Gram-positive cocci , methicillin-resistant Staphylococcus aureus and Enterococcus faecalis... 

Yet another mechanism has been the increased expression of one or more PBP in Enterococcus faecium. This overproduction of the PBP enables the overly produced PBP to take over the functions of the beta-lac-tam inhibited PBPs. A similar mechanism has been reported for methicillin-resistant Staphylococcus aureus. However where the E. faecium is a naturally occurring type of PBP related resistance, the MRSA results from a horizontal transfer of genetic material. Once transferred, the PBP production can be induced to overproduction following exposure to a beta-lactam. Again,... 

Indicated only for non-methicillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis. Compared to other penicillins, these penicillinase-resistant penicillins lack activity against Listeria monocytogenes and Enterococcus spp. 

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