Features of resistance formation to beta-lactam antibiotics in Francisella tularensis subsp. mediasiatica
Tsimbalistova, M.V.; Pavlovich, N.V.
Zhurnal Mikrobiologii Epidemiologii i Immunobiologii 1: 3-8
2014
ISSN/ISBN: 0372-9311 PMID: 24738287 Document Number: 677082
Determination of penicillin resistance features in tularemia causative agents of the mediasiatica subspecies, stability evaluation of differences in strains of various taxa and development of a rapid method of F. tularensis intraspecies differentiation. Beta-lactamase activity was determined in 30 strains of Francisella genus bacteria by quantitative iodometric method. All the strains regardless of subspecies membership were characterized by high resistance to beta-lactam antibiotics, and bacteria of the mediasiatica subspecies in contrast to other francisella did not synthesize beta-lactamase. Our attempts to induce beta-lactamase activity in vitro and in vivo in strains of this subspecies did not succeed. A method of intraspecies differentiation of F. tularensis by nitorcefin disks is proposed based on the distinctive feature. A high level of F. tularensis subsp. mediasiatica resistance to beta-lactams in vitro and their inefficiency during therapy of experimental tularemia due to a beta-lactamase negative strain suggests that F. tularensis beta-lactamase is not the leading factor in formation of native penicillin resistance of tularemia causative agent.