RT Journal Article T1 Tinidazole inhibitory and cidal activity against anaerobic periodontal pathogens A1 Alou Cervera, Luis A1 Giménez, María José A1 Manso, Francisco A1 Sevillano Fernández, David A1 Torrico, Martha A1 González Hidalgo, Natalia A1 Granizo, Juan José A1 Bascones Martínez, Antonio A1 Prieto Prieto, José A1 Maestre, Juan Ramón A1 Aguilar, Lorenzo AB The in vitro activity of tinidazole against anaerobic periodontal pathogens (25 Prevotella buccae, 18 Prevotella denticola, 10 Prevotella intermedia, 6 Prevotella melaninogenica, 5 Prevotella oralis, 10 Fusobacterium nucleatum and 8 Veillonella spp.) was determined by agar dilution. MIC(90) values (minimum inhibitory concentration for 90% of the organisms) were 8 microg/mL for Veillonella spp., 4 microg/mL for P. intermedia, 2 microg/mL for P. buccae, 1 microg/mL for Fusobacterium spp. and 0.5 microg/mL for other Prevotella spp. Cidal activity was studied by killing curves with tinidazole and amoxicillin (alone and in combination) at concentrations similar to those achieved in crevicular fluid (41.2 microg/mL tinidazole and 14.05 microg/mL amoxicillin) against an inoculum of ca. 10(7)colony-forming units/mL of four bacterial groups, each one composed of four different strains of the following periodontal isolates: Prevotella spp., Fusobacterium spp. and Veillonella spp. (anaerobes) and one amoxicillin-susceptible Streptococcus spp. (facultative) in a proportion of 1:1:1:1. When only beta-lactamase-negative Prevotella or Fusobacterium strains were tested, significantly higher reductions were found with amoxicillin (>4 log reduction at 48 h) versus controls. The presence of beta-lactamase-positive Prevotella spp. or F. nucleatum strains rendered amoxicillin inactive (no reductions at 48 h), with no differences from controls. Amoxicillin+tinidazole produced >3 log reduction at 24h and >4 log reduction at 48 h regardless of the presence or not of beta-lactamase-positive strains. The presence in crevicular fluid of beta-lactamases produced by beta-lactamase-positive periodontal pathogens may have ecological and therapeutic consequences since it may protect beta-lactamase-negative periodontal pathogens from amoxicillin treatment. In vitro, tinidazole offered high antianaerobic activity against beta-lactamase-positive and -negative periodontal pathogens, avoiding amoxicillin inactivation. PB Elsevier SN 0924-8579 YR 2009 FD 2009-05 LK https://hdl.handle.net/20.500.14352/107992 UL https://hdl.handle.net/20.500.14352/107992 LA eng NO Alou L, Giménez MJ, Manso F, Sevillano D, Torrico M, González N, Granizo JJ, Bascones A, Prieto J, Maestre JR, Aguilar L. Tinidazole inhibitory and cidal activity against anaerobic periodontal pathogens. Int J Antimicrob Agents. 2009 May;33(5):449-52. doi: 10.1016/j.ijantimicag.2008.10.012 DS Docta Complutense RD 27 oct 2025