JAC Advance Access originally published online on October 20, 2005
Journal of Antimicrobial Chemotherapy 2005 56(6):1047-1052; doi:10.1093/jac/dki362
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Evaluation of PPI-0903M (T91825), a novel cephalosporin: bactericidal activity, effects of modifying in vitro testing parameters and optimization of disc diffusion tests
1 JMI Laboratories, Inc., 345 Beaver Kreek Centre, Suite A, North Liberty, IA 52317, USA; 2 Tufts University School of Medicine, Boston, MA, USA; 3 Peninsula Pharmaceuticals, Alameda, CA, USA; 4 Universidade Federal de São Paulo, São Paulo, Brazil
Received 30 March 2005; returned 16 June 2005; revised 8 September 2005; accepted 12 September 2005
* Corresponding author. Tel: +1-319-665-3370; Fax: +1-319-665-3371; E-mail: helio-sader{at}jmilabs.com
Objectives: To evaluate bactericidal activity of PPI-0903M and in vitro testing parameters for this compound.
Methods: A total of 110 strains were tested to determine MIC and MBC values of PPI-0903M. MIC values were determined by reference broth microdilution whereas MBC was assessed by plating the broth from the MIC well and from those wells above the MIC for each organism onto appropriate drug-free growth media. Seventeen strains were tested by the kill-curve methodology to again evaluate the bactericidal activity of PPI-0903M. Broth microdilution results for 15 strains (in triplicate) were compared with the standard, reference method after modifying several testing parameters. Optimal disc content was assessed by testing seven reference strains with five PPI-0903M disc concentrations (5, 10, 30, 50 and 100 µg).
Results: PPI-0903MMBC/MIC ratios were 
4 in 90% of strains tested. Kill-curve studies showed >99.9% killing at concentrations 4x MIC within 8 to 24 h against staphylococci and Enterobacteriaceae tested. PPI-0903M MIC results were rarely influenced by the test or medium changes evaluated [high inoculum, low calcium or reduced pH (5.0)]. Human serum had no effect on in vitro antimicrobial activity of PPI-0903M. The 10 µg disc content would be recommended for optimal correlation of MIC breakpoints of 1–4 mg/L.
Conclusions: PPI-0903M was generally bactericidal against tested species, and the MIC results were stable across numerous susceptibility test condition changes.
Keywords: PPI-0903M , anti-MRSA cephalosporins , MRSA
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  C. Vidaillac, S. N. Leonard, H. S. Sader, R. N. Jones, and M. J. Rybak In Vitro Activity of Ceftaroline Alone and in Combination against Clinical Isolates of Resistant Gram-Negative Pathogens, Including {beta}-Lactamase-Producing Enterobacteriaceae and Pseudomonas aeruginosa Antimicrob. Agents Chemother., June 1, 2009; 53(6): 2360 - 2366. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. D. Brown and M. M. Traczewski In Vitro Antimicrobial Activity of a New Cephalosporin, Ceftaroline, and Determination of Quality Control Ranges for MIC Testing Antimicrob. Agents Chemother., March 1, 2009; 53(3): 1271 - 1274. [Abstract] [Full Text] [PDF]
|
|