Since antibiotic resistance is often associated with a fitness cost, bacteria employ multi-layered regulatory mechanisms to ensure that expression of resistance factors is restricted to times of antibiotic challenge. In Bacillus subtilis, the chromosomally-encoded ABCF ATPase VmlR confers resistance to pleuromutilin, lincosamide and type A streptogramin translation inhibitors. Here we show that vmlR expression is regulated by translation attenuation and transcription attenuation mechanisms. Antibiotic-induced ribosome stalling during translation of an upstream open reading frame in the vmlR leader region prevents formation of an anti-antiterminator structure, leading to the formation of an antiterminator structure that prevents intrinsic termination. Thus, transcription in the presence of antibiotic induces vmlR expression. We also show that NusG-dependent RNA polymerase pausing in the vmlR leader prevents leaky expression in the absence of antibiotic. Furthermore, we demonstrate that induction of VmlR expression by compromised protein synthesis does not require the ability of VmlR to rescue the translational defect, as exemplified by constitutive induction of VmlR by ribosome assembly defects. Rather, the specificity of induction is determined by the antibiotic's ability to stall the ribosome on the regulatory open reading frame located within the vmlR leader. Finally, we demonstrate the involvement of (p)ppGpp-mediated signalling in antibiotic-induced VmlR expression.

BackgroundKawasaki disease (KD) is recognized in developed countries as a fundamental reason of acquired heart diseases in children nowadays. The main treatment is infusion of intravenous immunoglobulin (IVIG) at a dose of 2 g/kg. However for about 10-30% of children is reported the development of resistance to standard therapy: continuance of fever (≥38,0 °C) or recurrency of fever after 36 hours afebrile period (T<37,5 °C), but not later than on the 7th day after completion of the IVIG infusion at a dose of 2 g/kg. Until now there are no unified recommendations for treatment of such patients. As alternative therapy researchers empirically apply second infusion of IVIG (77%), high doses of glucocorticoids (18%), blockers of tumor necrosis factor α (3%) and interleukin-1, cyclosporine and other cytostatic drugs.ObjectivesEfficacy evaluation of therapy by inhibitor of TNF-alpha (Etanercept) in treatment of KD immunoglobulin -resistant forms according to the data from Morozovskaya Children’s City Clinical Hospital,Moscow.MethodsThere were examined 152 patients (boys:girls – 2:1, median age Me = 21 months [10;36]) with KD hospitalized in Morozovskaya Children’s City Clinical Hospital in 2014-2018. The frequency of complete form of KD was 80,6%. All children had a standard therapy –IVIG. Efficacy evaluation was based on normalization of body temperature, decrease of neutrocytosis, decrease of C-reactive protein (CRP) level. In case of ineffectiveness of therapy the second infusion of IVIG, pulse-therapy and inhibitor of TNF-alpha (Etanercept) were usedResultsThe resistance to standard IVIG therapy was revealed in 16 children (10,5%), mostly in boys (4,3:1) at the age of Me = 21,5 months [9,5; 34]. Complete form of KD was diagnosed in 11 patients (68,8%), incomplete form - in 5 children (31,2%). Cardiovascular lesions were noted in 14 children (87,5%): pericarditis - in 2 (12,2%), coronary arteries (CA) lesions – in 12 (75%), with formation of aneurysms in 8 (50%), including the giant ones in 3 children (18,8%); peripheral arteries damages were noted in 2 children (12,5%), thrombosis and thromboembolism – in 4 children (25%).To all of children was made the second IVIG infusion, 13 of those children (81,2%) had a positive effect:11 children with complete form of KD, 2 children with incomplete form of KD. For 3 children (18,7%) with incomplete form of KD and significant cardiovascular changes (pericarditis, giant aneurysm of coronary and peripheral arteries,thrombosis and thromboembolism) it was needed an additional therapy. As a second-line therapy the methylprednisolone pulse-therapy was used in 2 children(12,5%) at a dose of 10 mg/kg, without sufficient effect. For these three patients(3) as a third-line therapy was applied Etanercept at a dose of 0,8 mg/kg/a week subcutaneousely. In all children normalization of body temperature, decrease of leukocytosis by factor of 1,5-3 and decrease of CRP by factor of 10-15 occurred after three injections of Etanercept. However, for 1 child it was needed the additional fourth inj...

Цель исследования-оценить эффективность и безопасность терапии метотрексатом (МТ) для подкожного (п/к) введения у пациентов с ювенильным идиопатическим артритом (ЮИА) без системных проявлений. Пациенты и методы. Представлены результаты проспективного исследования эффективности и безопасности МТ у 247 пациентов в возрасте от 1 года до 17 лет с суставными вариантами ЮИА, а также частота показаний для назначения генно-инженерных биологических препаратов данной категории больных. У всех пациентов ЮИА протекал без системных проявлений: у 106 был олигоартикулярный суставной синдром, у 94-полиартикулярный негативный по ревматоидному фактору (РФ), у 15-полиартикулярный позитивный по РФ, у 20-энтезитный, у 12-псориатический артрит. Диагноз ЮИА устанавливали на основании критериев ILAR. Всем пациентам после верификации диагноза назначался МТ в виде п/к инъекций в дозе 15 мг/м 2 /нед. Результаты и обсуждение. После 3 мес терапии МТ 50 и 70% улучшение по критериям ACRпеди было зарегистрировано у 65 и 53% пациентов соответственно. После 6, 9 и 12 мес терапии стадия неактивной болезни или ремиссия отмечалась у 44,5; 85 и 100% пациентов соответственно. Выводы. Парентеральное введение МТ способствует достижению ремиссии заболевания и восстановлению функции суставов у пациентов с ЮИА без внесуставных проявлений. Наряду с высокой терапевтической эффективностью МТ обладал хорошей переносимостью и благоприятным профилем безопасности.