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Use of folic acid casei medium reveals trimethoprim susceptibility of Lactobacillus species
Author(s) -
Danielsen M.,
Andersen H.S.,
Wind A.
Publication year - 2004
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1111/j.1472-765x.2004.01471.x
Subject(s) - lactobacillus casei , section (typography) , identification (biology) , folic acid , library science , trimethoprim , biology , microbiology and biotechnology , medicine , advertising , genetics , computer science , botany , antibiotics , bacteria , business
Aim: Lactobacilli have been reported to have intrinsic resistance to trimethoprim. The susceptibility of lactobacilli to trimethoprim on different media was investigated in order to search for a phenotypic test method that could indicate the presence of acquired resistance genes. Methods and Results: Strains of Lactobacillus acidophilus , Lact. paracasei , Lact. rhamnosus and Lact. plantarum were susceptibility tested with E‐tests on folic acid casei medium (FACM), MRS and defined medium 1. The effects of addition or removal of nucleosides and thymidine phosphorylase were investigated. E‐tests on FACM yielded reproducible minimal inhibitory concentrations (MICs) for trimethoprim but addition of nucleosides was necessary for growth of Lact. acidophilus . MICs for the tested strains were 0·125–0·19, 0·25–3 and 0·064–0·19 μ g ml −1 for Lact. paracasei , Lact. rhamnosus and Lact. plantarum , respectively. With the addition of deoxyuridine and deoxyadenosine to FACM the MICs of Lact. acidophilus were 0·064–1 μ g ml −1 . Conclusions, Significance and Impact of the Study: Lactobacilli do not have intrinsic resistance to trimethoprim. The results show that trimethoprim susceptibility testing of the tested Lactobacillus species is possible and indicate that transferable resistance genes are absent in all the tested strains.