MACROLIDE ANTIBIOTIC INHIBITION OF TRANSLATION AND 50S RIBOSOMAL-SUBUNIT ASSEMBLY IN METHICILLIN-RESISTANT STAPHYLOCOCCUS-AUREUS CELLS

Methicillin-resistant Staphylococcus aureus cells were treated with th ree macrolide antibiotics to examine the inhibitory effect of the drug s on the growth rate and cell viability. Inhibition of protein synthes is and 50S ribosomal subunit assembly were also examined. The growth r ate and cell viability were reduced by each antibiotic in both erythro mycin-susceptible and erythromycin-resistant MRSA organisms. Translati on and the formation of the 50S ribosomal subunit were inhibited to an equal extent in the erythromycin-susceptible cells, but protein synth esis was affected to a greater extent by each macrolide in the erythro mycin-resistant organisms. Clarithromycin was the most inhibitory of t he three compounds, followed by erythromycin and azithromycin in relat ive effectiveness. The use of these compounds against MRSA organisms i s discussed.