RT Journal Article T1 In vitro interference of β-lactams with biofilm development by prevalent community respiratory tract isolates A1 Maestre, Juan Ramón A1 Mateo, María A1 Méndez, María Luisa A1 Aguilar, Lorenzo A1 Gimenez, María José A1 Alou Cervera, Luis A1 Coronel, Pilar A1 Granizo, Juan José A1 Prieto Prieto, José AB Interference of cefditoren (CDN) and amoxicillin/clavulanic acid (AMC) with biofilm production was studied using 11 Streptococcus pneumoniae isolates with minimum inhibitory concentrations (MICs) ranging from 0.015microg/mL to 0.5microg/mL for CDN and from 0.06microg/mL to 2microg/mL for AMC (except for one isolate with an AMC MIC of 8microg/mL) and 5 Haemophilus influenzae isolates with MICs of 0.03-0.06microg/mL for CDN and 0.5-16microg/mL for AMC. Slime production was assessed in antibiotic-free medium and with 0.03microg/mL CDN or 1/0.5microg/mL AMC by measuring the optical density at 450nm (OD(450)). Significantly lower mean OD(450) values were obtained for S. pneumoniae with antibiotics compared with controls (CDN, 0.088 vs. 0.118, P=0.003; and AMC, 0.095 vs. 0.112, P=0.003), with significant correlation between both antibiotics (r=0.752; P=0.008). Percent reduction in OD(450) values was higher for CDN compared with AMC (24.02% vs. 15.92%; P=0.008). For H. influenzae, significantly lower mean OD(450) values were obtained with CDN compared with controls (0.083 vs. 0.096; P=0.043) but not with AMC (0.086 vs. 0.095; P=0.08). Comparing percent reductions in S. pneumoniae versus H. influenzae for each antibiotic, no differences were found for AMC (15.92% vs. 9.40%; P=0.36), with a tendency for CDN (24.02% vs. 13.79%; P=0.069). Different beta-lactams may have different capabilities of interfering with S. pneumoniae biofilm development when tested under the same experimental conditions. PB Elsevier SN 0924-8579 YR 2010 FD 2010-03 LK https://hdl.handle.net/20.500.14352/107047 UL https://hdl.handle.net/20.500.14352/107047 LA eng NO Maestre JR, Mateo M, Méndez ML, Aguilar L, Gimenez MJ, Alou L, Coronel P, Granizo JJ, Prieto J. In vitro interference of beta-lactams with biofilm development by prevalent community respiratory tract isolates. Int J Antimicrob Agents. 2010 Mar;35(3):274-7. NO Tedec-Meiji Farma S.A. DS Docta Complutense RD 25 abr 2025