In-vitro susceptibility, tolerance and glycocalyx production in Streptococcus mutans De La Higuera, A. Castillo, A. Gutiérrez Fernández, José García-Mendoza, A. Liébana, J. This study was partially supported by the Andalusian Regional Government through the research project ‘Microbiology, Immunology and Epidemiology of Oral Diseases’ We studied the presence of high-level resistance to aminoglycosides, penicillin tolerance and glycocalyx production in 160 isolates of Streptococcus mutans. Susceptibility to amoxycillin, cefazolin, imipenem, erythromycin, clindamycin, vancomycin and teicoplanin was also investigated. Of the isolates analysed, 58.8% produced glycocalyx in vitro and 2.5% were penicillin-tolerant. High-level resistance to streptomycin was found in 16.3% of the isolates, but all were sensitive to all other antibiotics tested. We found no significant relationship between glycocalyx production and high-level streptomycin resistance, penicillin tolerance or antibiotic susceptibility, except for a greater susceptibility to clindamycin and vancomycin in isolates that produced glycocalyx. Although our findings reflect the clinically favourable pattern of susceptibility currently found in this species, the appearance in some isolates of resistance, tolerance and glycocalyx production should be investigated because of the risks involved in endocarditis caused by S. mutans. 2024-04-23T10:35:16Z 2024-04-23T10:35:16Z 1997-09 journal article De la Higuera A, Castillo A, Gutiérrez J, García-Mendoza A, Liébana J. In-vitro susceptibility, tolerance and glycocalyx production in Streptococcus mutans. J Antimicrob Chemother. 1997 Sep;40(3):359-63. DOI:10.1093/jac/40.3.359 https://hdl.handle.net/10481/91081 10.1093/jac/40.3.359 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Oxford University Press