Use Of Macrolides In Treatment Research Articles

The use of macrolides in treatment of upper respiratory tract infections

Antimicrobial resistance is a growing problem among upper respiratory tract pathogens. Resistance to beta-lactam drugs among Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes is increasing. As safe and well-tolerated antibiotics, macrolides play a key role in the treatment of community-acquired upper respiratory tract infections (RTIs). Their broad spectrum of activity against gram-positive cocci, such as S. pneumoniae and S. pyogenes, atypical pathogens, H. influenzae (azithromycin and clarithromycin), and Moraxella catarrhalis, has led to the widespread use of macrolides for empiric treatment of upper RTIs and as alternatives for patients allergic to beta-lactams. Macrolide resistance is increasing among pneumococci and recently among S. pyogenes, and is associated with increasing use of the newer macrolides, such as azithromycin. Ribosomal target modification mediated by erm(A) and erm(B) genes and active efflux due to mef(A) and mef(E) are the principal mechanisms of resistance in both S. pneumoniae and S. pyogenes. Recently, ribosomal protein and RNA mutations have been found to be responsible for acquired resistance to macrolides in S. pneumoniae, S. pyogenes, and H. influenzae. Although macrolides are only weakly active against macrolide-resistant streptococci species, producing an efflux pump (mef), and are inactive against pathogens with ribosomal target modification (erm), treatment failures are uncommon. Therefore, macrolide therapy, for now, remains a good alternative for treatment of upper RTIs; however, continuous monitoring of the local resistance patterns is essential.

The use of macrolides in treatment of upper respiratory tract infections

Antimicrobial resistance is a growing problem among upper respiratory tract pathogens. Resistance to beta-lactam drugs among Streptococcus pneumoniae, Haemophilus influenzae, and Streptococcus pyogenes is increasing. As safe and well-tolerated antibiotics, macrolides play a key role in the treatment of community-acquired upper respiratory tract infections (RTIs). Their broad spectrum of activity against gram-positive cocci, such as S. pneumoniae and S. pyogenes, atypical pathogens, H. influenzae (azithromycin and clarithromycin), and Moraxella catarrhalis, has led to the widespread use of macrolides for empiric treatment of upper RTIs and as alternatives for patients allergic to b-lactams. Macrolide resistance is increasing among pneumococci and recently among S. pyogenes, and is associated with increasing use of the newer macrolides, such as azithromycin. Ribosomal target modification mediated by erm(A) and erm(B) genes and active efflux due to mef(A) and mef(E) are the principal mechanisms of resistance in S. pneumoniae and S. pyogenes. Recently, ribosomal protein and RNA mutations have been found responsible for acquired resistance to macrolides in S. pneumoniae, S. pyogenes, and H. influenzae. Although macrolides are only weakly active against macrolide-resistant streptococci species producing an efflux pump (mef) and are inactive against pathogens with ribosomal target modification (erm), treatment failures are uncommon. Therefore, macrolide therapy, for now, remains a good alternative for treatment of upper RTIs; however, continuous monitoring of the local resistance patterns is essential.

Characterization of glycopeptide-resistant enterococcus faecium (GRE) from broilers and pigs in Denmark: genetic evidence that persistence of GRE in pig herds is associated with coselection by resistance to macrolides.

Glycopeptide-resistant enterococci (GRE) from broilers and pigs were characterized to investigate the background for the persistence of GRE in pig herds. All porcine isolates belonged to closely related pulsed-field gel electrophoretic (PFGE) types, with the ermB and vanA genes located on the same transferable genetic element. Broiler isolates belonged to different PFGE types. The persistence of GRE in Danish pig herds after the ban of glycopeptides may be explained by the genetic link between ermB and vanA and coselection by use of macrolides for treatment and growth promotion.

Comparative in vitro evaluation of dirithromycin tested against recent clinical isolates of Haemophilus influenzae, moraxella catarrhalis, and streptococcus pneumoniae, including effects of medium supplements and test conditions on MIC results

The use of macrolides for treatment of respiratory complaints has been complicated by susceptibility test conditions that adversely effect the in vitro test results and perceived potencies of these compounds. Dirithromycin was studied as to its in vitro activity compared to other macrolides as well as the effects that environmental incubation variations and inoculum concentrations may have on susceptibility results. Dirithromycin was less active than other macrolides tested (azithromycin, clarithromycin, erythromycin) against Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis with MIC 90 values of 16, 32, and 1 μg/ml, respectively; an activity that was most similar to roxithromycin. This reduced activity may be counteracted by the superior pharmacokinetic properties that dirithromycin possesses compared to other members in its class. Method variation studies show that incubation in CO 2 environments increase the MIC values for all macrolide compounds and dirithromycin was most effected by pH changes in three in vitro methods tested (Etest [AB BIODISK, Solna, Sweden] broth microdilution, and disk diffusion). Variations in inoculum concentration had minimal effect on dirithromycin potency. In addition the variability (lack of reproducibility) of the test results with dirithromycin were not significant. Dirithromycin is an alternative therapeutic choice among macrolide compounds for treatment of community-acquired respiratory infections caused by various streptococci, Legionella pneumophilia, Mycoplasma pneumoniae and M. catarrhalis, and also possesses a modest in vitro potency versus H. influenzae coupled with excellent pharmacokinetic properties. In vitro tests with dirithromycin will continue to be problematic for H. influenzae because of the adverse effects of recommended CO 2 incubation for some standardized methods or commercial products (Etest).