Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 9/22/2005
Publication Date: 9/22/2005
Citation: Halling, S.M., Jensen, A.E. 2005. Susceptibility of brucella to macrolides: Analyses of the 23S rDNA, L4 and L22 [abstract]. North Central Branch American Society for Microbiology. p.44.
Technical Abstract: The variable susceptibility of Brucella classical biovars to erythromycin was observed by Margaret Meyer (Advances in Brucellosis Research, 1990, p.26.), suggesting that this might be due to ribosomal structure/function differences providing insights into the relationships among these bacteria. The Etest was used to determine the relative susceptibility of the classical Brucella spp. biovars and three marine isolates to the macrolides, erythromycin, clarithromycin, and azithromycin. MICs for these antibiotics ranged from less than 1 ug/ml to greater than 256 ug/ml. Susceptibility to macrolides among the Brucella was species specific with one notable exception, B. abortus biovar 2. The most susceptible Brucella were B. suis biovars, B. canis, B. neotomae, B. ovis, B. abortus biovar 2 and the marine isolates. The least susceptible were the B. abortus biovars, except biovar 2, and B. melitensis. The most common loci reported that confer resistance to these antibiotics were sequenced and compared: 23S rRNA and ribosomal proteins L4 or L22, encoded by rplD and rplV, respectively. The DNA sequences of 23S ribosomal RNA and ribosomal proteins rplD and rplV were polymorphic but no absolute correlation between genotypes and resistance patterns were detected. Dendograms constructed based on the sequences determined here clustered the Brucella spp. similar to those constructed from physical restriction endonuclease maps.