Carbapenem-nonsusceptible (Carba-NS) Acinetobacter baumannii has emerged as an important cause of nosocomial infections. In the present study, we characterized 91 Carba-NS A. baumannii isolates collected from patients of surgical departments and intensive care units at three hospitals in Moscow in 2012–2015. Multilocus sequence typing (MLST) using the Oxford (Oxf) scheme identified 16 sequence types (STs) of three clonal complexes (CCs), including CC92 ^Oxf (67%), CC109 ^Oxf (1%), CC944 ^Oxf (29%), and the singleton ST1100 ^Oxf (3%). CC944 ^Oxf was composed of ST944 ^Oxf ( n = 16) and two of its newly described single locus variants ST1103 ^Oxf ( n = 3) and ST1104 ^Oxf ( n = 7); all the three STs were identical to the Pasteur (Pas) MLST scheme ST78. All CC944 ^Oxf /ST78 ^Pas isolates were bla _OXA-40-like positive and all but one isolate harbored a bla _CTX-M-like gene. ST944 ^Oxf was the only ST found in each of the three study hospitals. Biofilm growth capacity was similar among Carba-NS and nonclonal carbapenem-susceptible isolates. Our data demonstrate the predominance of two clonal lineages among Carba-NS A. baumannii . One of these, the uncommon bla _OXA-40-like / bla _CTX-M-like -positive clone of CC944 ^Oxf /ST78 ^Pas , seems to be endemic in Russia.

Introduction. Infections associated with carbapenem-resistant (Carba-R) Klebsiella pneumoniae (KP) are a serious public health problem because they lead to an increase in hospital stays, treatment costs, and an increase in patient morbidity and mortality. Aim to characterize antimicrobial resistance, virulence factors and genotypes of Carba-R KP strains isolated from patients in intensive care and surgical units. Materials and methods. In total, 455 KP strains that were resistant to meropenem and/or imipenem, or susceptible to meropenem and/or imipenem at increased exposure were collected in 20182020. For further analysis, total 90 KP strains isolated from clinically significant sites blood/сerebrospinal fluid/urine/lower respiratory tract/wounds/abdominal cavity of patients in intensive care and surgical units were selected. Antibiotic susceptibility was determined using the broth microdilution method. Carbapenemase genes were detected by real-time PCR. The virulence genes and K1/K2 capsular serotypes were determined by multiplex PCR. Sequence types (ST) were determined using multilocus sequence typing. Results. Most of the selected isolates (97%) were recognized as extensively drug-resistant pathogens, three isolates were classified as multidrug-resistant pathogens. The major determinant of carbapenem resistance was blaOXA-48-like (53%), blaNDM-group was detected in 13% strains, a combination of blaNDM-group and blaOXA-48-like genes was found in 31% isolates. Two isolates harbored blaKPC-group. Most of the isolates had the virulence genes entB (100%), mrkD (99%), and ybtS (78%). The iutA gene was found in 16% strains. Four isolates had kfu gene and four strains carried rmpA gene. The K2 capsule type was determined in 13% isolates. Four ST dominated in the studied population: ST395 (26%), ST2975 (19%), ST198 (12%) and ST307 (11%). Conclusion. Carba-R KP isolates had a high level of resistance not only to carbapenems, but also to antibiotics of other classes. Carbapenem resistance was mainly associated with OXA-48 carbapenemase. The entB, mrkD and ybtS genes were the main determinants of virulence. The epidemically successful clones CG395 and CG307 were the predominant genetic lines. Resistance to antimicrobials was combined with the presence of various virulence factors. The data obtained are important for the epidemiological surveillance of the spread of KP and have important clinical implications.

Introduction. Carbapenemase-producing Klebsiella pneumoniae (CP-Kp), which are international high-risk clones, have become a problem of utmost importance. CP-Kps, adapting to the hospital environment, evolve into convergent pathotypes. Such variants combine traits of two genetic lineages: multidrug resistant (MDR) and hypervirulent. The pathotypes, along with MDR K. pneumoniae, pose an exceptional threat to young patients during systemic infection. The objective of this study is the detailed molecular genetic analysis of MDR isolates of K. pneumoniae detected during the monitoring of resistant Gram-negative bacteria at the National Medical Research Center for Children’s Health in 2014–2021. Materials and methods. Whole-genome sequencing with a subsequent bioinformatics analysis of eight MDR isolates from the bloodstream and cerebrospinal fluid. Results. MDR isolates belonged to 4 sublineages (SL): SL307, SL395, SL29 and SL1198. In the genomes of 6 pangrug-resistant (PDR) isolates, genes associated with resistance to all categories of antibiotics recommended for Enterobacteriaceae therapy were identified. Plasmids were present in all genomes. In 6 isolates, plasmids contained heavy metal ion resistance operons in addition to antibiotic resistance genes. Prophages within the plasmids were also involved in the transfer of resistance genes. The ST395 isolate from the cerebrospinal fluid belonged to the convergent pathotype in terms of resistance and virulence. Comparison of genomes within SLs revealed recombination events in the K- and O-locus regions and the Yersiniabactin operon. Conclusion. Thus, in a sample of resistant K. pneumoniae isolated from bloodstream and cerebrospinal fluid, 6 PDR isolates were detected, one of which belongs to the convergent pathotype ST395.

Introduction. Currently, there is no any unified approach to the treatment of complicated forms of acute appendicitis in children. The purpose of our study is to evaluate the effectiveness of the local Protocol for diagnostics and treatment of appendicular peritonitis (AP) in children. Material and methods. 149 children with AP, aged 2 - 17 (11 ± 3.5 ), were included into the study. All of them were treated at the Clinical and Research Institute Emergency Pediatric Surgery and Trauma (CRIEPST) in 2015-2018. In the gender structure, boys (104; 69.8%) prevailed over girls (45; 30.2%). The following parameters were evaluated: AP structure, surgical tactics, postoperative course (incidence of postoperative intestinal failure syndrome (IFS), postoperative complications, length of hospital stay). A tactics for surgical treatment and volume of intensive care in the postoperative period were defined depending on AP severity and according to the local Protocol. Laparoscopic appendectomy was performed in 145 (97.3%) patients. There were no intraoperative complications and conversions in the studied group. In case of periappendiular abscess (PA) 3 (2.7%), patients had puncture and abscess drainage under ultrasound control. Results. While analyzing the AP structure by forms , the following picture was shown: free and abscessed forms were approximately equal - 72 (48.3%) and 77 (51.7%), respectively (p > 0.05). Diffuse peritonitis - 31.5%; generalized - 16.8%; combined - 17.4%; periappendicular abscess (PA) stage 1-14.8%; PA 2-16.8%; PA 3-2.7%. Postoperative complications - 4 (2.7%): postoperative abdominal abscesses - 3 (2.0%); early adhesive intestinal obstruction - 1 (0.7%). In postoperative abscesses, puncture and drainage were performed under ultrasound control; in early adhesive intestinal obstruction - laparoscopic adhesiolysis. All the children recovered. Length of intensive care was 2.9 ± 1.8 days; hospitalization - 12.0 ± 5.2 days. Conclusion. The local Protocol developed by the researchers helps to define a surgical tactics and volume of intensive care in the postoperative period. Laparoscopic surgery, in the vast majority of cases, is an optimal and effective technique for AP surgical treatment in children. Contraindications to laparoscopic surgery are PA 3 and total abscessing peritonitis.

Обоснование. Известна важная роль митохондрий в механизмах повреждения и гибели клеток мозга при черепно-мозговой травме (ЧМТ). Однако вопросы взаимоотношений между тяжестью повреждения мозга при ЧМТ и митохондриальной дисфункцией окончательно не решены. Цель исследования: определить активность NADH- и сукцинатдегидрогеназ —ключевых ферментов окислительного фосфорилирования митохондрий; содержание аденозинтрифосфата в лимфоцитах при ЧМТ; уровень NOx и 3-нитротирозина в периферической крови у детей, перенесших травмы различной степени тяжести и имеющих разные исходы ЧМТ. Материалы и методы: определение указанных показателей проводилось в динамике до одного месяца, а в отдельных случаях — вплоть до гибели больных. Тяжесть ЧМТ оценивали в баллах по шкале комы Глазго, исход ЧМТ — по шкале исходов Глазго. Детей с ЧМТ на основании клинической оценки разделили на 3 группы — с легкой, тяжелой и с тяжелой ЧМТ и летальным исходом. Результаты: исследования показали, что активность дегидрогеназ достоверно снижалась только у больных с тяжелой ЧМТ и неблагоприятным исходом. Наибольшее снижение этих показателей выявлено у больных с летальным исходом. Обнаружена прямая корреляционная зависимость между показателями активности дегидрогеназ и содержанием аденозинтрифосфата в лимфоцитах (r =0,97, p =0,005). Содержание метаболитов NOx у детей с тяжелой ЧМТ на порядок превышало их уровень у здоровых детей и больных с легкой ЧМТ. Уровень 3-нитротирозина в плазме крови был тем выше, чем тяжелее была ЧМТ. Заключение. Обнаруженные при ЧМТ у детей митохондриальная дисфункция, нарушение мозгового энергетического обмена и окислительный стресс могут приводить к повреждению и гибели клеток мозга, а также быть мишенями для адекватной терапии ЧМТ.

Objective - assessment of RT-PCR for the detection of carbapenem-resistance genes in gram-negative bacteria. A total, 499 strains of gram-negative microorganisms isolated in two pediatric hospitals in 2019-2020 were studied. Species identification was performed using MALDI-ToF mass-spectrometry (Bruker Daltonics, Germany). Meropenem and imipenem minimal inhibitory concentration (MIC) was determined by E-test method (BioMerieux, France). The presence of acquired carbapenemase genes of IMP, NDM, VIM, KPC, OXA-48, OXA-23, OXA-40, OXA-58-groups was determined by RT-PCR. Klebsiella pneumoniae (34%), Escherichia coli (4%), Serratia marcescens (6%) and other members of Enterobacterales (6%), also gram-negative non-glucose-fermenting bacteria Acinetobacter baumannii (14%), Pseudomonas aeruginosa (36%) were found among selected strains. Carbapenemase production was found in 385 isolates (77%). The main mechanism determining carbapenem resistance in P. aeruginosa was the production of blaVIM (100%). A. baumanii strains harbored OXA-23 (55%) and OXA-40 (45%) carbapenemases. The major determinant of carbapenem resistance in K. pneumoniae isolates was OXA-48 carbapenemase, detected in 63% strains, 13% of the strains possessed blaNDM-group, 16% isolates had a combination of blaNDM-group and blaOXA-48-like. Carbapenemase of KPC-group was found in 8% K. pneumoniae strains. OXA-48 carbapenemase prevailed (95%) among S. marcescens strains. Most of E. coli isolates harbored metallo-beta-lactamase NDM (89%). Other members of Enterobacterales most often had OXA-48 carbapenemase (57%), 39% of the isolates carried blaNDM-group. In one strain, a combination of blaNDM-group and blaOXA-48-like was discovered. RT-PCR is a fast and reliable method for the detection of acquired carbapenemases and can be recommended for routine use in bacteriological laboratories.