The introduction of novel drugs into treatment must be accompanied by continuous phenotypic susceptibility testing and the analysis of genetic determinants of resistance.

The purpose of the present study was to analyse mutations in the gyrA and gyrB genes of Mycobacterium tuberculosis and define the possible correlation between these mutations and resistance to levofloxacin (LVX), moxifloxacin (MFX) and gatifloxacin (GAT), based on their MICs. One hundred and forty-two M. tuberculosis clinical isolates were collected from pulmonary tuberculosis patients in the Moscow region. All M. tuberculosis strains were tested for drug susceptibility to rifampicin and isoniazid using the BACTEC MGIT 960 System and to ofloxacin (OFX) using the absolute concentration method on solid Lowenstein-Jensen slants. All in all, 68 strains were selected at random (38 strains were resistant and 30 were susceptible to OFX) for further analysis using the TB-BIOCHIP-2 test system and DNA sequence analysis. The MICs of LVX, MFX and GAT for selected strains were determined using the BACTEC MGIT 960 System. Mutations in the gyrA gene were observed in 36 out of 38 (94.7 %) OFX-resistant M. tuberculosis strains. Asn538Asp and Asp500His substitutions in the gyrB gene only were found in two (5.3 %) strains. Twenty-nine out of 30 OFX-sensitive M. tuberculosis strains had no mutations in either gene. One (3.3 %) OFX-sensitive M. tuberculosis strain carried an Arg485His substitution in gyrB. The results of our investigation showed that there is no clear correlation between the type of mutation in the genes gyrA and gyrB, and the MIC levels of LVX, MFX and GAT for resistant strains. Mutations in gyrA and Asn538Asp, and Asp500His substitutions in gyrB were associated with cross-resistance of M. tuberculosis to fluoroquinolones. The substitution Arg485His in gyrB does not confer resistance to LVX, MFX and GAT in M. tuberculosis. INTRODUCTIONFluoroquinolones (FQs) are highly active antimicrobial agents, which are widely used in chemotherapy against multidrug-resistant (MDR) tuberculosis (TB). However, the application of ofloxacin (OFX), ciprofloxacin and levofloxacin (LVX) for the treatment of undiagnosed respiratory infections led to the development of resistance in Mycobacterium tuberculosis isolates (Wang et al., 2007). Moreover, the initial occurrences of resistance to FQs were observed in MDR strains and isoniazid (IHN)-and rifampicin (RIF)-susceptible strains isolated from newly diagnosed TB patients (Delgado & Telenti, 1996;Xu et al., 2009).The most promising drugs undergoing phase III trials are the fourth generation FQs, such as moxifloxacin (MFX) and gatifloxacin (GAT), which demonstrated high in vivo and in vitro activities against MDR strains and OFX-resistant and ciprofloxacin-resistant MDR strains (Zhao et al., 1999;Rodríguez et al., 2002;Poissy et al., 2010;Merle et al., 2012).Recent studies have shown that resistance to all FQs is due to mutations (single nucleotide polymorphisms, SNPs) not only in the gyrA (320 bp) gene, but also in the gyrB (375 bp) gene, which encode the respective subunits of the DNA topoisomerase gyrase (Takiff et al., 1994;Ginsburg et al., 2003;Shi et al., 2006;Lau et al., 2011). Th...

ObjectiveThe objective of the research was to assess the susceptibility of the slowly growing nontuberculous mycobacteria strains to the antimicrobial drugs used for mycobaterioses treatment using SLOMYCO test system.Materials and methodsWe assessed 363 NTM strains: 177 MAC (161 M. avium, 16 M. intracellulare), 112 M. kansasii and 74 M. xenopi collected from the respiratory material of the patients were under the treatment or under diagnostic procedures at our Center, affiliates and the diagnostic department in 2010–2016. Drug sucseptibility for NTM was tested using the Sensititre SLOWMYCO system (TREK DIAGNOSTIC Systems Ltd., UK). MICs were established by microdilutions in Mueller-Hinton broth on polystyrene 96-well plates. The statistical analysis was done using the StatGraphics Plus 5.0 software. The data were compared pairwise using Pearson χ2 test with Yates correction. 95% confidence interval (CI) were calculated. Statistically significant differences were considered for p <0.05. Log-rank test and Kaplan-Meier curves were used to assess the concentration-dependent surveillance probability.ResultsThe statistically significant differences were revealed in sensitivity/resistance isolates of M. avium and M. intracellulare: M. avium strains were resistant to higher concentrations of amikacin, clarithromycin, linezolid and streptomycin (p <0.01); M. intracellulare strains were resistant to higher concentrations of ethionamide (p <0.05). The isolates of M. avium were significantly more resistant than M. kansasii to amikacin, doxycycline, isoniazid, clarithromycin, linezolid, moxifloxacin, rifabutin, rifampicin, streptomycin, trimethoprim/sulfamethoxazole, ciprofloxacin, ethambutol, ethionamide (visible growth of M. avium were inhibited by higher drug concentrations, p <0.01). The isolates of M. avium showed significantly higher resistance than M. xenopi to amikacin, doxycycline, isoniazid, clarithromycin, linezolid, moxifloxacin, rifampicin, streptomycin, trimethoprim/sulfamethoxazole, ciprofloxacin, ethambutol, and ethionamide (visible growth of M. avium were inhibited by higher drug concentrations, p <0.01). Statistically significant differences in the dynamics of the response to the antibacterial effects of isoniazid, linezolid, moxifloxacin, rifampicin, trimethoprim/sulfamethoxazole, ethambutol, and ethionamide were found for M. intracellulare and M. xenopi (complete inhibition of the visible growth of M. intracellulare required higher drugs concentrations, p <0, 05). Comparison of the Kaplan-Meyer curves revealed statistically significant differences in survialence probability of M. kansasii and M. xenopi for amikacin, doxycycline, rifampicin, trimethoprim/sulfamethoxazole, ciprofloxacin, ethambutol, and ethionamide (a higher number of isolates of M. xenopi were inhibited by low drugs concentrations, p <0.05).ConclusionsOur data show that M. avium and M. intracellulare were more resistant to the majority of the studied drugs than M. kansasii and M. xenopi.

Since beta(2)-glycoprotein I (beta(2)GPI) was described as the major antigenic target for antiphospholipid antibodies, many studies have focused their attention to the physiological role of beta(2)GPI and anti-beta(2)GPI antibodies on autoimmune-mediated thrombosis. Studies reporting the physiological role of beta(2)GPI have been numerous, but the exact mechanism of action(s) has yet to be completely determined. beta(2)GPI's epitopes for anti-beta(2)GPI autoantibodies have been characterized, however, not all of the heterogeneous anti-beta(2)GPI antibodies are pathogenic. The pathophysiologic role of beta(2)GPI has been reported in the fields of coagulation, fibrinolysis, angiogenesis, and atherosclerosis. Our understanding of the impact of beta(2)GPI, its metabolites and autoantibodies to beta(2)GPI on these physiological functions may contribute to the development of better therapeutic strategies to treat and prevent autoimmune-mediated atherothrombotic vascular disease.

Infectious cellular response may be proatherogenic,while the humoral response (antibody production) maybe protective. We review the recent progress in our understanding of autoimmunity and infectious immunity that promote atherosclerosis.