Antimicrobial susceptibility of Mycobacterium marinum determined by E-test and agar dilution.
Mycobacterium marinum is recognized as a cutaneous pathogen requiring antibiotic treatment. We compared the E-test with a reference agar dilution method for susceptibility testing of M. marinum to amikacin, ciprofloxacin, clarithromycin, doxycycline, rifampicin, trimethoprim-sulfamethoxazole and ethambutol. MICs obtained after 6 d showed agreement between the E-test and agar dilution within +/- 2 dilutions in 95% of all cases for amikacin, ciprofloxacin, doxycycline and rifampicin. Inhibitory concentrations of trimethoprim-sulfamethoxazole were difficult to define using the E-test because of gradually decreased growth in the presence of increasing concentrations. For clarithromycin, results were generally 1-3 dilution steps lower with the E-test and for ethambutol they were often > 3 dilution steps lower. These differences always appeared in the low MIC range and did not affect the categorization of the strains as susceptible to these 2 antimicrobial agents. All strains were interpreted as susceptible to all tested antibiotics, except for doxycycline, according to recommended breakpoints. Overall, our results suggest that the E-test can be considered an alternative for susceptibility testing of certain antibacterial agents against M. marinum.
Werngren
J
J
Department of Bacteriology, Swedish Institute for Infectious Disease Control (SMI), Solna.
Olsson-Liljequist
B
B
Gezelius
L
L
Hoffner
S E
SE
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015169:Colony Count, Microbial; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D019910:Mycobacterium marinum / Q000187:drug effects* / Q000254:growth & development / Q000302:isolation & purification
D000900:Anti-Bacterial Agents