Journal of Antimicrobial Chemotherapy (1999) 43, 707-709
© 1999 The British Society for Antimicrobial Chemotherapy
Brief report |
Comparison of agar dilution, microdilution, Etest and disc diffusion to test the activity of trovafloxacin against Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus and Streptococcus pneumoniae
a Departments of Pathology (Clinical Microbiology), Hershey Medical Center, 500 University Drive, Hershey, PA 17033; b Case Western Reserve University, Cleveland, OH 44106, USA
To investigate the ability of four in-vitro methods to test trovafloxacin activity, this
study evaluated susceptibility of 101 isolates of each of
Pseudomonas aeruginosa
, methicillin- resistant
Staphylococcus aureus
and
Streptococcus pneumoniae
to trovafloxacin by agar dilution, microdilution, Etest and disc diffusion methodologies. MIC
50 and MIC
90
values were very similar for all three species with all four methods. For
S. aureus
and
P. aeruginosa,
good correlation was obtained between breakpoints of 
17 mm, 14- 16 mm and 
13 mm with agar and microdilution MICs. For both species, Etests yielded susceptibility rates
lower than the other three methods. For pneumococci, excellent correlation was obtained with
all four methods.
* Corresponding author. Tel: +1-717-531-5113; Fax: +1-717-531-7953; E-mail: pappelbaum{at}psghs.edu