Vancomycin resistance

FCC,b c trimethoprim-sulfamethoxazole, clindamycin ampidllin-sulbadam, or amoxidllin[Pg.393]

Cardiac surgery S. aureus, Staphylococcus epidermidis, Corynebaderium Cefazolin 1 g every 8 hours x 48 hours Patients >80 kg should receive 2 g of cefazolin instead in areas with high prevalence of 5. aureus resistance, vancomycin should be considered IA... 

Methicillin-resistant Vancomycin TMP-SMZ,1 minocycline, linezolid, daptomycin, tigecycline... 

Staphylococcus aureus Abscesses bacteremia cellulitis endocarditis osteomyelitis pneumonia others If methicillin-sensitive nafcillin or oxacillin If methicillin-resistant vancomycin gentamicin or rifampin 1 st-generation cephalosporin clindamycin erythromycin trimethoprim-sulfamethoxazole a penicillin + a penicillinase inhibitor... 

Streptococcus pneumoniae Arthritis otitis pneumonia sinusitis If penicillin sensitive ampicillin or penicillin G or V If penicillin resistant vancomycin rifampin A cephalosporin erythromycin azithromycin clarithromycin imipenem meropenem a fluoroquinolone trimethoprim-sulfamethoxazole... 

Regimen for Methicillin-Resistant Vancomycin hydrochloride Staphylococci 30 mg/kg per 24 h IV in 2 or 4 equally >6 ... 

Cardiothoracic S. aureus, S. epidermidis, Corynebacterium, enteric gram-negative bacilli Cefazolin 1 g q8h x 48h Second-generation cephalosporins also have been advocated In areas with high prevalence of S. aureus resistance, vancomycin should be considered... 

Although glycopeptide resistance as a result of morphological adaptation is only indirectly related to enzymatic mechanism (and thus peripheral to the focus of this review) it merits summary, as relevant introduction to the basis for the second, and enzymatic, mechanism of vancomycin resistance. Vancomycin and teicoplanin interfere with cell wall biosynthesis as a result of their ability to form a noncovalent complex with the -D-Ala-D-Ala dipeptide terminus of the peptide stem of peptidoglycan precursors (Figure As described previously (with reference to /3-lactam resistance), the key event in early stage of peptidoglycan... 

The role of the penicillinase-resistant penicillins for most staphylococcal disease is decreasing with the increasing frequency of so-called methicilhn-resistant microorganisms. Both S. aureus and S. epidermidis increasingly are resistant. Vancomycin is the drug of choice for serious infection caused by methicillin-resistant variants of these strains rifampin is given concurrently when a foreign body is present. 

MECHANISMS OF ACTION AND RESISTANCE Vancomycin inhibits ceU wall synthesis by binding with high affinity to the D-Ala-D-Ala terminus of precursor units (Figure 46-4). It is bactericidal for dividing microorganisms. 

ANTIBACTERIAL ACTIVITY Because of its unique mechanism of action, linezolid is active against strains that are resistant to multiple other agents, including penicilhn-resistant strains of S. pneumoniae, methicillin-resistant, vancomycin-intermediate and vancomycin-resistant strains of staphylococci and vancomycin-resistant strains of enterococci. 

Staphylococcus (methicillin-resistant) Vancomycin TMP-SMZ. VRSA linezolid or streptogramin... 

Other specific discovery assays have been used such as differential inhibition of a vancomycin resistant S. aureus strain and its susceptible parent, and an assay based on antagonism of the antibacterial activity by N,A/-diacetyl-L-Lys-D-Ala-D-Ala [24570-39-6] a tripeptide analogue of the dalbaheptides receptor. AppHcation of this latter test to 1936 cultures (90) led to the isolation of 42 dalbaheptides, six of which, including kibdelin (Table 3), parvodicin (Table 3), and actinoidin A2 (68) were novel. A colorimetric assay based on competition between horseradish peroxidase bound teicoplanin and the... 

This resistance, inducible by low concentrations of dalbaheptides, is plasmid mediated and is transferable. Concomitant with the induction of resistance is the appearance or increased expression of a protein having a molecular weight of either 39,500 or 39,000. The enzymatic activity of this material has been postulated (112). Although the mechanism of resistance induction by dalbaheptides is unknown, different dalhabaheptides have different induction capacity. Vancomycin (39) is the most powerful inducer teicoplanin is a very weak inducer. 

Vancomycin group of antibiotics and the fight against resistant bacteria 99AG(E)1172. 

As recently as 1970, only about 30 naturally occurring organohalogen compounds were known. It was simply assumed that chloroform, halogenated phenols, chlorinated aromatic compounds called PCBs, and other such substances found in the environment were industrial pollutants. Now, only a third of a century later, the situation js quite different. More than 5000 organohalogen compounds have been found to occur naturally, and tens of thousands more surely exist. From a simple compound like chloromethane to an extremely complex one like vancomycin, a remarkably diverse range of organohalogen compounds exists in plants, bacteria, and animals. Many even have valuable physiological activity. Vancomycin, for instance, is a powerful antibiotic produced by the bacterium Amycolatopsis orientalis and used clinically to treat methicillin-resistant Staphylococcus aureus (MRSA). 

Problems of recent years involving listeriosis, salmonellosis, giardiasis and Legionnaire s disease have received attention, as have the re-emergence of tuberculosis and the importance of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). 

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... 

Gaspar-Marques,C. Rijo,P. Sim5es, M. F. Duarte,M. A. Rodriguez, B. Abietanesfrom Plectranthus grandidentatus and P. hereroensis against methicillin- and vancomycin-resistant bacteria. Phytomedicine 2006, 13, 267-271. 

Inpatient treatment of methicillin-resistant S. aureus can consist of IV vancomycin or oral agents as described above, depending on the severity of infection and concomitant organisms. IV vancomycin may also be converted to oral step-down therapy upon discharge. 

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