In vitro interference of cefditoren on slime production by Streptococcus pneumoniae
Abstract number: P1801
Maestre J.R., Mateo M., Gimenez M.J., Aguilar L., Mendez M.L., Granizo J.J., Alou L., Coronel P., Prieto J.
Objectives: To explore the in vitro effect of cefditoren (CDN) on slime production by slime-producing Streptococcus pneumoniae strains belonging to different serotypes and with different CDN MICs.
Methods: Eleven S. pneumoniae isolates with the following CDN MICs (mg/l) were used: 0.015 (serotypes 23A and 21), 0.03 (serotype 31), 0.06 (serotype 42), 0.25 (serotypes 6B and 35B) and 0.5 (serotypes 9V 2 strains 14, 19A and 23F). Slime production was assessed as previously described (J Clin Microbiol 1985;22:9961006), with modifications, in microtiter plates with HTM in the absence of CDN (basal) and in the presence of CDN 0.03 mg/l, by measuring optical density (OD) at 450 nm using an spectrophotometer. S. pneumoniae R6 was used as positive control and non-inoculated HTM broth as negative control. All experiments were performed 12 times and mean values were considered.
Results: The Figure shows mean OD corresponding to basal determinations (triangles, continuous line) and determinations in the presence of CDN (squares, dotted line) for the eleven strains distributed by CDN MIC.
Conclusion: CDN at supra-inhibitory concentration (strains with MIC of 0.015 mg/l), inhibitory concentration (strain with MIC of 0.03 mg/l) or sub-inhibitory concentration (strains with MIC of 0.060.5 mg/l), reduced slime production in slime-producing S. pneumoniae strains, regardless the serotype or the magnitude of basal slime production.
|Session name:||19th European Congress of Clinical Microbiology and Infectious Diseases|
|Location:||Helsinki, Finland, 16 - 19 May 2009|
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