Vancomycin alternative antibiotics

Some streptococci have developed a different mechanism of acquired resistance to penicillin drugs. These bacteria have altered transpeptidases (also known as penicillin-binding proteins) that no longer bind penicillin, and thus peptidoglycan synthesis is not disrupted. This mechanism of resistance is found in Streptococcus pneumoniae. Estimates of penicillin-resistant S. pneumoniae in the United States range from 25% to 66%, including strains recovered from ocular and periocular infections. Many isolates of penicillin-resistant S.pneumoniae also are resistant to the cephalosporins, macrolides, and the older fluoroquinolones. Use of alternative antibiotics such as vancomycin is necessary for infections caused by penicillin-resistant isolates. 

Initial therapy should include discontinuation of the offending agent with a change to an alternative antibiotic if possible. Fluid and electrolyte replacement therapy is necessary. Although diarrhea will resolve in 15% to 23% of patients without therapy, most patients will require antibiotics. Both vancomycin and metronidazole are effective, but metronidazole 250 mg orally four times daily is the drug of choice. It is similar to vancomycin in time to resolution of diarrhea, incidence of side effects, and relapse rates. However, it is less expensive than vancomycin, and the concern for vancomycin resistance promotes metronidazole use. 

Due to the increasing resistance of most staphylococci to gentamicin, other alternative antibiotics such as vancomycin, tobramycin, chndamycin, fusidic acid, cefamandol. 

In penicillin-allergic patients, oral or parenteral clindamycin may be used. Alternatively, a first-generation cephalosporin such as cefazolin (1 to 2 g IV every 6 to 8 hours) may be used cautiously for patients who have not experienced immediate or anaphylactic penicillin reactions and are penicillin skin test negative. In severe cases in which cephalosporins cannot be used because of documented methicillin resistance or severe allergic reactions to /1-lactam antibiotics, IV vancomycin should be administered. 

Penicillin antibiotics must be used with caution because some strains of Bacillus anthracis possess an enzyme that inactivates penicillin. Other antimicrobial agents can be used as alternatives if the listed drugs are unavailable or in short supply. These include erythromycin, imipenem, clindamycin, vancomycin, and chloramphenicol.3... 

In the case of vancomycin [72], an original study was performed to obtain a well-defined stationary phase structure, since it was reasonably assumed that the antibiotic is randomly linked to the silica by one or both of its amino groups, one belonging to the disaccharide portion (primary), and the other one to the heptapeptide core (secondary). Thus, alternate fluorenylmethyloxycarbonyl (FMOC)-amino-protected derivatives were prepared and immobilized in a packed column, and then vancomycin was recovered by cleavage of the protecting groups. The two defined CSPs obtained, when compared with the CSP produced from native randomly linked vancomycin, showed lower retention and enantioselectivity, also if they still separated the same compounds. Thus, no advantages could be found to choose these phases as an alternative to the native vancomycin CSP. 

Even newer is the natural product daptomycin (Cubicin), a complex cyclic lipopeptide structure, approved for use in the United States in 2003. Daptomycin has a spectrum similar to that of linezolid and specifically includes MRSA and VRE. In contrast to linezolid, daptomycin is bactericidal for these Gram-positive organisms. It is, like vancomycin, a parenteral antibiotic and is given intravenously. It is indicated for treatment of complicated skin and skin structure infections and for some cases of bacteremia, including endocarditis. Daptomycin may be thought of as an alternative to vancomycin. 

INDOMETACIN AMINOGLYCOSIDES T amikacin, gentamicin, and vancomycin levels in neonates Uncertain indometacin possibly 1 renal clearance of these aminoglycosides Halve the dose of antibiotic. Uncertain whether this applies to adults but suggest check levels. Otherwise use an alternative NSAID... 

Our recent work on the study of binding of the antibiotic vancomycin to bacterial cell wall with isothermal titration calorimetry also illustrated the effect of entropy enthalpy compensation (119). The backbone of the cell wall is made up of alternating V-acetylglucosamine (NAG) and V-acetylmuramic acid (NAM). The NAM residues are incorporated with a pentapep-tidyl stem, which terminates in acyl-D-Ala-D-Ala. The study found that the binding of vancomycin to the acyl-D-Ala-D-Ala... 

Pharmacokinetics of vancomycin Renal transport of vancomycin Epidemiology of vancomycin nephrotoxicity Risk factors for nephrotoxicity Therapeutic drug monitoring of vancomycin Prevention of vancomycin nephrotoxicity Alternative gram positive antibiotics References ... 

Although the intraperitoneal administration of antibiotics offers a convenient and effective treatment alternative for PD-related peritonitis, potential toxicities should be considered. Chemical peritonitis is a potential toxicity associated with IP vancomycin therapy. A series of early reports of chemical peritonitis with vancomycin snggested that the problem may be brand-specific or associated with large doses (1 to 2 g). One prospective study suggested the incidence may be as high as 23% with IP doses of 1 g or more. There may be a hypersensitivity component to the effect, yet patients exhibiting chemical peritonitis have received subsequent doses without adverse effects. The exact etiology of vancomycin-associated chemical peritonitis remains to be clarified. IP amphotericin B also causes pain and chemical peritonitis. However, since IV amphotericin B poorly penetrates into the peritoneal cavity the therapeutic options are limited. ... 

Vancomycin has been used in combination with anion-exchange resins dosed to avoid drug-resin binding, and this has been used successfully in a small number of cases. " Cholestyramine 4 g orally three to four times daily and colestipol 5 g orally twice daily have been used as alternatives to antibiotics in mild cases. 

A type of bacteria called enterococci possess enzymes that weave together alternating protein-sugar strands to create a tough cell wall—the bacteria s main defense against the outside world. The antibiotic drug vancomycin interferes with production of the cell wall (see drawing/illustration above). This kills the bacteria, which stops infection. 

FIGURE 100 Vancomycin, a bactericidal antibiotic, inhibits cell-wall synthesis in Gram-positive bacteria. It is effective against methicillin-resistant organisms and as an alternate to semisynthetic penicillins or cephalosporins in patients with severe staphylococcal infections. 

In penicillin-allergic patients, vancomycin is an effective alternative for the treatment of endocarditis caused by viridans streptococci or, combined with an aminoglycoside, for enterococcal endocarditis. Vancomycin has become an important antibiotic in the management of known or suspected penicillin-resistant pneumococcal infections. 

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