Susceptibility testing of macrolide and lincosamide antibiotics according to DIN guidelines. Deutsches Institut für Normung.
The in-vitro activity of azithromycin, clarithromycin, erythromycin, josamycin, midekamycin, roxithromycin and clindamycin against 674 Gram-negative and Gram-positive clinical isolates, including methicillin-resistant Staphylococcus aureus, was determined by agar dilution, microdilution and agar diffusion with Mueller-Hinton medium according to the Deutsches Institut für Normung (DIN) 58940 guidelines. The results obtained by regression analysis and the error-rate-bounded method of Metzler-DeHaan indicate that common interpretative criteria (breakpoints) for test discs may be assigned to susceptible/resistant Gram-positive strains for all antibiotics tested. The following tentative DIN values are suggested for 15 microg macrolide discs: for susceptible Gram-positive and Gram-negative strains, an inhibition zone diameter (IZD) of > or = 26 mm at a corresponding MIC of < or = 2 mg/L; for resistant Gram-positive strains, an IZD of < or = 21 mm; for resistant Gram-negative strains, an IZD of < or = 19 mm at a corresponding MIC of > or = 8 mg/L. For Haemophilus influenzae only, breakpoints for azithromycin are suggested with IZDs of > or = 21 mm for susceptible and < or = 18 mm for resistant.
Schmalreck
A F
AF
Microbiology Laboratories Research & Development, Pfizer/Mack, H. Mack Nachf., Illertissen, Germany.
Kottmann
I
I
Reiser
A
A
Ruffer
U
U
Schlenk
R
R
Vanca
E
E
Wildfeuer
A
A
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D006094:Gram-Positive Bacteria / Q000187:drug effects*; D017408:Guidelines as Topic; D006193:Haemophilus influenzae / Q000187:drug effects; D006801:Humans; D055231:Lincosamides; D018942:Macrolides / Q000494:pharmacology; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects
D000900:Anti-Bacterial Agents; D055231:Lincosamides; D018942:Macrolides