title: In vitro activity of cefditoren and other antimicrobial agents against 288 Streptococcus pneumoniae and 220 Haemophilus influenzae clinical strains isolated in Zaragoza, Spain.
abstract: In vitro cefditoren antimicrobial activity was tested against 288 Streptococcus pneumoniae and 220 Haemophilus influenzae clinical strains isolated in our hospital from January 2005 to May 2006 by agar dilution and broth microdilution method, respectively. MICs were also determined for 13 and 10 comparison drugs, respectively. The pneumococci tested comprised 113 (39.2%) penicillin susceptible, 91 (31.6%) penicillin intermediate, and 84 (29.2%) penicillin resistant. Cefditoren was the most active drug on the basis of the MICs (MIC(90)=0.5 microg/mL), followed by ceftriaxone and levofloxacin (MIC(90)=1 microg/mL). Cefditoren MICs ranged from 0.25 to 1 microg/mL for ceftriaxone-resistant isolates, with a modal MIC of 0.5 microg/mL and an MIC(90) of 1.0 microg/mL. No S. pneumoniae isolates evaluated in this study showed MICs to cefditoren higher than 1 microg/mL (MIC range, <or=0.015 to 1 microg/mL). Against penicillin-resistant pneumococci, the rank order of intrinsic activity (MIC(90), microg/mL) was cefditoren (0.5)<ceftriaxone (2.0)=cefotaxime (2.0)<amoxicillin/clavulanate (8.0)=amoxicillin (8.0)=cefuroxime (8.0). Among the 220 strains of H. influenzae, 42 (19.09%) produced a beta-lactamase (Hi beta+) and 3 (1.1%) were beta-lactamase (Hi beta-) negative but have reduced susceptibility to ampicillin (BLNAR). The most active drugs on the basis of MICs were cefditoren and levofloxacin, showing MIC(50) and MIC(90) values of 0.015/0.06 microg/mL. Cefditoren at concentration of 0.06 microg/mL inhibited all 3 BLNAR (ampicillin MICs >4 microg/mL). Against H. influenzae (Hi beta+), the rank order of intrinsic activity (MIC(90), microg/mL) was cefditoren (0.03) < cefixime (0.06)<ceftriaxone (0.12)=cefotaxime (0.12)<cefuroxime (1.0)<amoxicillin/clavulanate (2.0)<ampicillin (>8.0).
authors: Department of Microbiology, Hospital Clinico Lozano Blesa, 50009 Zaragoza, Spain. cristinaseral@hotmail.com
authors: Cristina
authors: C
authors: Seral
authors: Laura
authors: L
authors: Suárez
authors: Carmen
authors: C
authors: Rubio-Calvo
authors: Rafael
authors: R
authors: Gómez-Lus
authors: Mercedes
authors: M
authors: Gimeno
authors: Pilar
authors: P
authors: Coronel
authors: Estrella
authors: E
authors: Durán
authors: Raquel
authors: R
authors: Becerril
authors: Mercedes
authors: M
authors: Oca
authors: F Javier
authors: FJ
authors: Castillo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002511:Cephalosporins / Q000494:pharmacology*; D006192:Haemophilus Infections / Q000382:microbiology; D006193:Haemophilus influenzae / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010403:Penicillin Resistance; D011008:Pneumococcal Infections / Q000382:microbiology; D011018:Pneumonia, Pneumococcal / Q000382:microbiology; D012141:Respiratory Tract Infections / Q000382:microbiology*; D013030:Spain; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C073460:cefditoren