Vol 11, No 3 (2021)

Melioidosis is a life-threatening infection caused by Burkholderia pseudomallei, an environmental Gram-negative bacterium, inhabitant of moist soils in the tropics and subtropics. There is no licensed vaccine against melioidosis. The main routes of B. pseudomallei infection are percutaneous inoculation, inhalation, or ingestion. Individual cases of vertical, sexual, zoonotic, and nosocomial transmission of melioidosis are described. Risk factors for infection are contact with soil or water (especially during the rainy season). The age over 45, type 2 diabetes, alcoholism, liver disease, chronic lung disease, chronic renal disease, and thalassemia, as well as long-term use of steroids and immunosuppressive therapy, are the main susceptibility factors for melioidosis. Among the affected adult residents of endemic regions, 80% had one or more predisposing factors, among children — about 20%. No significant influence of concomitant diseases on the development of melioidosis in travelers was found. Less than 50% of patients had predisposing factors. The incubation period of melioidosis ranges within 1—21 days; on average, 9 days, in case of sizeable infectious dose, it can be less than one day. There is no post-infectious immunity, and reinfection can occur with a different B. pseudomallei strain after successful treatment. B. pseudomallei is a facultative intracellular pathogen that can invade and multiply inside a wide range of cells, including phagocytic. The acute form of melioidosis is characterized by pneumonia, multiple abscesses, bacteremia, and systemic sepsis. Chronic, subacute, and latent forms are also possible. Antimicrobial therapy is divided into the initial intensive phase and the subsequent eradication phase. B. pseudomallei is resistant to penicillins, first- and second-generation cephalosporins, aminoglycosides, macrolides, chloramphenicol, fluoroquinolones, tetracyclines, trimethoprim, and in some cases to co-trimoxazole, and rarely to ceftazidime. Early diagnosis and appropriate management are crucial in reducing severe complications leading to high mortality, and in preventing disease recurrences. However, there is no pathognomonic melioidosis-specific feature, and the disease is not well known to physicians and microbiologists. The results of serological tests for detection of specific antibodies are ambiguous. The bacterial load of the tested sample limits the detection of antigens. Among the accelerated methods for identifying the causative agent of melioidosis, PCR has the highest sensitivity and specificity. Automated identification using microbiological analyzers generally shows good results, but about 15% of isolates are misidentified. Time-of-flight mass spectrometry with matrix-assisted laser desorption ionization is potentially useful for rapid identification of B. pseudomallei. However, existing databases require optimization by adding the reference spectra for B. pseudomallei.

In this Section we provide new data on the pathogenetic factors in pediatric convulsive syndrome, including a prominent role of viral infection in developing seizures and epilepsy (EPL) in children, as evidenced by clinical and experimental studies. Various forms of convulsive syndrome associated with viral infection include febrile convulsions and febrile epileptic status, encephalitis-related acute symptomatic seizures, and postencephalitic epilepsy. The human herpesvirus-6 isolated in temporal lobe epilepsy is a frequent causative agent of febrile seizures and febrile epileptic status. Febrile seizures and, especially, febrile epileptic status are associated with further developing epilepsy. Of special note is the febrile infection-related epileptic syndrome (FIRES) more often affecting school-aged children and characterized by extremely severe course and unfavorable outcome. Convulsive syndrome is associated with systemic inflammation and overproduced pro-inflammatory cytokines that increase permeability of the blood-brain barrier and functional activity of brain-resident cells, which are involved in eliciting seizures and maintaining epileptogenesis. Taking into consideration the key role of inflammation underlying convulsive syndrome, in recent decades cytokines and chemokines have been widely studied as possible prognostic criteria for epileptogenesis. Neuron-specific proteins are examined as markers of brain cell damage in various inflammatory diseases of the central nervous system. The first Section of the review presented current understanding on systemic and local cytokine/chemokine response in viral encephalitis. Here we present clinical trials published within the last 5—7 years assessing cytokines/chemokines and neuron-specific proteins in children with various forms of convulsive syndrome, including epilepsy. Association between biomarker level and disease clinical parameters as well as potential for their use to diagnose and predict its further course are discussed.

The aim of the study was to investigate the phenotypic features of peripheral blood B-lymphocytes in patients with widespread purulent peritonitis (WPP) during postoperative treatment depending on the disease outcome. 52 patients with acute surgical diseases and injuries of the abdominal organs complicated by WPP were examined. Blood sampling was performed before surgery (preoperative period), as well as on day 7, 14 and 21 of the postoperative period. All patients with WPP were divided into two groups depending on the disease outcome during postoperative period: patients with favorable outcome (n = 34), patients with unfavorable outcome (n = 18). 68 healthy subjects were included into control group. Immunophenotyping of blood B-lymphocytes was assessed by flow cytometry and direct immunofluorescence of whole peripheral blood stained with monoclonal antibodies. It was found that patients with WPP in preoperative period contained lowered B1-cell subset compared to control group that was paralleled with low absolute B-lymphocyte count. Moreover, a higher number of activated (based on upregulated CD23 expression) peripheral blood B1-lymphocytes was observed in the patients with unfavorable than in patients with favorable WPP outcome. In addition, dynamics of changes in frequency of B-lymphocytes during postoperative period (day 7—21) varied profoundly depending on the disease outcome. In particular, patients with favorable WPP outcome during postoperative period were found to contain decreased percentage of the most B-cell subsets (including activated cells) examined, whereas patients with unfavorable disease outcome had virtually unaltered B-cell composition in the postoperative period. Moreover, count of total B-cells, naive B-cells and B2-cells negative or positive for CD23 expression was higher in patients with unfavorable outcome than in patients with favorable WPP outcome throughout entire postoperative period. Percentage of some other B-cell subsets in patients with unfavorable than with favorable outcome was also higher only at certain stages of postoperative treatment. It is assumed that such features in peripheral blood B-cell subset composition were closely linked to the disease outcome so that patients with unfavorable WPP outcome turned out to have disturbed B-cell maturation and migration in developing immune response that might be due to lowered total sensitivity of host body to postoperative antibiotic therapy.

The protection against tuberculosis infection is largely determined by the ability of host tissue macrophages to limit the growth and spread of mycobacteria. Able to multiply within the host macrophages, mycobacteria have developed a number of protective mechanisms preventing phagosome-lysosome fusion, thereby evading damaging effects of lysosomal enzymes. Saposins are small, acidic, thermostable, non-enzymatic glycoproteins that participate as co-fac-tors in degradation of short oligosaccharide head group glycosphingolipids. Saposins A, B, C and D are formed in acidic endosomes due to cleavage of initial prosaposin molecule. The effect of saposins on human immune response is mediated by their involvement in presenting mycobacterial antigens on CD1 molecules. Preliminary studies with electron microscopy allowed to uncover saposin D-bound damaging effect on Mycobacterium tuberculosis in acidic environment. These data allowed us to suggest that saposin D is an important protective component fighting against TB infection. The aim of the study was to explore how saposin D deficiency might affect formation of anti-tuberculosis immune response and ability of macrophages to inhibit M. tuberculosis growth. Materials and methods. Interstitial pulmonary macrophages and peritoneal macrophages were isolated from wild type C57BL/6 strain and saposin D deficient C57BL/6-SapD-/- mouse strains. Results. It was found that as compared to macrophages from mice, macrophages from wild type strain significantly better controlled mycobacteria growth in vitro. To study an opportunity of compensating for deficient saposin D in peritoneal macrophages from C57BL/6-SapD-/- mice, a saposin D gene-bearing lentiviral vector was created. Transfection of SAPD-deficient peritoneal macrophages with expression vector compensated for saposin D deficiency in such cells and restored bactericidal function. The mechanisms of action for current anti-TB drugs are mediated by various metabolic pathways in mycobacteria (inhibited biosynthesis of fatty acids, arabinogalactan, peptidoglycan and protein; inhibition of DNA-dependent processes, proton pumps and cytochrome P450-dependent monooxygenases). Conclusion. It was shown that saposin D deficiency affects activation of macrophage bactericidal function in vitro. Our study data may be a prerequisite for biologically substantiated potential of using a vector construct bearing natural human protein gene such as saposin D, as a new anti-tuberculosis drug.

Pleural tuberculosis (pTB) is a very common form of extrapulmonary tuberculosis (TB). pTB diagnostics represents a major burning challenge worldwide due to the limitations of available conventional diagnostic tools. These latter include microscopic examination of the pleural fluid for acid-fast bacilli, mycobacterial culture of pleural fluid in solid or liquid media, sputum or pleural tissue, and histopathological examination of pleural tissue; these tests have recognized limitations for clinical use. Hence, to overcome these limitations, attention has been devoted to new nucleic acid amplification (NAA) diagnostic tests such as the polymerase chain reaction (PCR) and real-time PCR (RT-PCR), owing to their accuracy, rapidity, high sensitivity and specificity. Within this context, this prospective study was conducted to evaluate the performance of molecular diagnosis methods for differentiation between tuberculosis and non-tuberculosis pleural effusions. Fifty patients with pleural effusion were enrolled in this prospective study in Rabat, Morocco. The efficacy of conventional polymerase chain reaction (PCR) in the diagnostics of tuberculous pleurisy by targeting IS6110 and mycobacterial internal transcribed spacer (MYITS) was evaluated compared to histopathologic examination and culture data. Our results showed that IS6110 PCR could “rule in” pTB, the sensitivity and specificity being 41.6% and 85.7%, respectively. Therefore, the findings confirmed that molecular tests exert a relatively high specificity in EPTB but lower sensitivity, thus a positive test is considered as a pTB case whereas negative one cannot exclude the disease. Although the study was limited by a small sample size, it adds to the body of evidence of usefulness of molecular testing as adjuncts to histopathologic examination for accurate diagnosis of pTB, to treat timely and to avoid the emergence and spread of drug resistant pTB. However, further efforts should be made to increase the sensitivity of NAA methods and to identify the best molecular targets to be useful in clinical practice.

Here we provide molecular and genetic characteristics of the Klebsiella pneumoniae KP254 clinical strain belonging to clonal group 23 based on the genome-wide sequencing data. It is known that representatives of such clonal group exert highly virulent properties and cause community-acquired infections. Phenotypically, K. pneumoniae KP254 strain is characterized by multidrug resistance, including carbapenems. The determinants of antibiotic resistance (bla_SHV-1, oqxAB, fosA) and pathogenicity encoding fimbriae 1, 3 types and the siderophore yersineobactin synthesis were found in the chromosome structure. However, there was uncovered the lack of conjugative element ICEKp1, the pathogenicity island KPHPI208, and the allantoin regulon genes which are often found in highly virulent strains. Analyzing nucleotide sequences in silico allowed to reveal the replicons of incompatibility group plasmids for FII, FIA_HI1/FII_K, Col_440I, Col_pVC, FIB_K, FII_pCRY. Combining contigs relative to reference sequences by using the BLASTN service allowed to identify two putative antibiotic resistance plasmids IncFII and IncFII_pCRY as well as one virulence plasmid IncFIB_K. The determinants of the aerobactin siderophore, the RmpA2 mucoid phenotype regulator as well as heavy metal resistance genes constitute the virulence plasmid structure. The virulence plasmid nucleotide sequence coverage comprised 93% relative to the virulence plasmid pK2044 with 99.38% identity level; the genomic regions responsible for the salmochelin and RmpA protein synthesis were deleted. The set of antibiotic resistance determinants identified in the mobilome structure includes the genes for beta-lactamase LAP-2 (IncFII_pCRY plasmid) — a TEM-1 analogue, as well as extended-spectrum beta-lactamase CTX-M-55 (IncFII plasmid), both of which are rarely recorded in the Russian Federation. Additionally, widespread genes bla_OXA-1, aac(3’)-IIa, ΔcatB4, aac (6’)-Ib-cr, tet(A), qnrSI, sul2, catA2 were also found in the plasmid DNA. The carbapenemase genes are absent in the resistome structure, whereas the examined strain exerts carbapenem resistance. The analysis of the ompK35 and ompK36 porin gene translated sequences revealed mutational changes which resulted in emerged stop codon within the ompK35 gene, whereas OmpK36 amino acid sequence contains a large number of substitutions, insertions, and deletions. The changes identified serve as one of the factors determining the carbapenem resistance. A synergistic effect may be accounted for by activity of the efflux pumps found in the structure of the K. pneumoniae KP254 genome, particularly AcrAB-TolC and KpnEF. Thus, the strain examined by us preserves the most significant signs specific to the highly virulent evolutionary branch Klebsiella strains, and at the same time, acquires the multidrug resistance genetic determinants.

Healthcare-workers are at risk of contact with measles patients and disease transmission. Measles-infected employees of healthcare facilities may contribute to the nosocomial measles spread and serve as a source of infection for most susceptible cohorts such as pregnant women, neonates, and immunocompromised patients. In order to study the humoral immunity against measles in healthcare workers and reveal factors associated with seronegative status, we performed a cross-sectional study by enrolling 847 healthcare workers of the Arkhangelsk Regional Clinical Hospital. Anti-measles virus serum immunoglobulin G antibodies were quantified by using VectorMeasles-IgG ELISA kit (Vector-Best, Russia). According to the manufacturer's recommendations specific IgG anti-measles titer cut-off value higher than 0.18 IU/ml, equal to 0.12—0.17 IU/ml, or lower than 0.12 IU/ml was considered as positive (protective), equivocal, or negative, respectively. Assessing an impact of employee's gender, age, affiliation (department), current position was carried out by using binary logistic regression analysis while analyzing seronegative status of healthcare workers. Study participants dominated by females (92.1%). The median age was 48 (39; 57) years. The employees of somatic departments prevailed (26.7%). It was found that 93.7% of medical workers had concentration of anti-measles antibodies exceeding magnitude of protective titer (above 0.18 IU/ml), 4.4% and 1.9% were measles seronegative and equivocal, respectively. The level of antibodies against measles was associated with age of healthcare workers, but not with gender. All employees older than 60 years were measles seropositive, whereas those younger than 35 or within range 35 to 60 years of age had protective antibody titer in 77% and 95.5% of cases, respectively. The proportion of subjects with seronegative results did not depend on employee's position (doctor, nurse, cleaning worker), but varied a lot between different hospital departments. According to the data of logistic regression, the odds to have a seronegative test result among employees from somatic and remaining departments were 4.4-fold higher. Importantly, the rate of seronegative results was by 10-fold lower in employees born between 1968 and 1984 than those found in subjects born after 1985. On the other hand, subjects older than 60 years of age were seronegative at 50-fold lower rate than those who were under 35. The median concentration of measles immunoglobulin G among vaccinated healthcare workers vs. subjects recovered after natural infection was significantly lower reaching 0.56 IU/ml and 4.2 IU/ml (p < 0.001), respectively. Five-year monitoring showed that titer of measles IgG antibodies decreased by 1.2-1.9-fold (average — 1.5). Thus, a cohort of healthcare workers from multidisciplinary healthcare facility demonstrated that the proportion measles-susceptible subjects was 6.3%. Importantly, age of examined subjects mainly affected seronegative status. Taking into consideration age-related lowered serum antibody level in vaccinated healthcare workers, seroprevalence studies and subsequent revaccination of seronegative people should be performed at least once every 5 years to prevent measles spread in healthcare facilities.

A search for prognostic markers of HIV and tuberculosis coinfection (HIV/TB), especially in case of Mycobacterium tuberculosis multidrug resistance (MDR MBT) associated with low rates of TB eradication, is of relevance in connection with the problem of choosing adequate anti-TB therapy which is able to decrease mortality. 113 HIV/TB patients aged 24 to 58 years were examined: 70 males and 43 females hospitalized at the Novokuznetsk TB Clinic during the 2017—2019 period. MDR MBT (concomitant resistance to Isoniazid and Rifampicin) was found in 50 patients (12 patients with MDR MBT had additional resistance to Fluoroquinolones) aged 24 to 54 years — 31 males and 19 females. The control group consisted of 49 healthy individuals aged 27 to 72 years (26 females and 23 males) lacking focal and systemic infections with moderately pronounced age-related changes. In plasma samples, concentration of total (non-specific) immunoglobulins of classes E, M, G, A (including secretory immunoglobulin A, sIgA) were measured by using enzyme-linked immunosorbent assay. Data statistical processing was performed by using licensed software packages InStatII, Microsoft Excel, IBM SPSS Statistics 22. An extended range of individual variability in count of peripheral blood CD4 lymphocytes was revealed both among non-survivor and survivor patients with HIV/TB examined, being a drawback of using such parameter as lethality predictor. It was found that the serum level of total IgE, IgM, IgG, IgA and sIgA in patients with HIV/ TB was higher than that one in control group, whereas in non-survivor vs. survivor patients the concentration of IgE and sIgA was elevated. The coefficient of disease outcome prediction (CP) for patients with HIV/TB and MDR MBT was calculated being equal to the ratio of the multiplication of serum concentration of IgE, IgM, IgA and secretory IgA to CD4 lymphocyte count (CP = IgE x IgM x IgA x sIgA/CD4). CP higher than 200 was detected in 77% non-survivor and 6% of survivor patients. The relative risk of death with CP > 200 was very high (OR = 56.7, p < 0.0001) being 8.5 times higher than that one upon CD4 < 200 (OR = 6.7, p = 0.0237). A positive correlation between CP and lethal outcome was more valuable than that of CD4. The data presented allow us to propose CP for clinical use as an effective prognostic criterion for HIV/TB with MDR MBT.

The spleen is a secondary immune and the largest organ of the reticuloendothelial system, actively involved during infectious mononucleosis. Clinically, assessing a degree of organ involvement in the pathological process seems unlikely. As a rule, only palpation and percussion are used to determine the size of the spleen, which represents a late and subjective sign of potential splenomegaly. Ultrasound examination provides ample opportunities to estimate the spleen size during infectious mononucleosis. Our study was aimed at identifying morphometric and Doppler ultrasound changes in the spleen in patients with infectious mononucleosis. Materials and methods. There were enrolled 24 patients with infectious mononucleosis to be compared with 30 healthy medical institute students in control group. All participants underwent splenic ultrasound examination. Spleen echotexture and contour clarity together with measuring linear dimensions: length, width, and thickness were analyzed. Splenic artery and vein velocity parameters were measured at the gates of the spleen. Elastographic window for fibroelastometry was positioned within the window for standard grayscale examination. Measurements were performed at 5 or more points of the spleen parenchyma at least 4—5 mm away from the capsular zone and the zone of large vessels. Based on the morphometric measurements obtained, the mass, spleen mass coefficient (SMC), as well as the spleen mass/body height ratio and spleen mass/body surface area ratio were calculated. Results. We found that patients with infectious mononucleosis had the length, thickness and weight of the spleen significantly greater than those observed in control group. However, the mass of the spleen varies widely and justified to calculate the CMS as an objective criterion to assess the size of the spleen. It was revealed that infectious mononucleosis may proceed in one of the three variants of the splenic response: decreased size, CMR < 1.5; normal size, CMR ranged from 1.5 to 4; splenomegaly, CMR > 4. Splenomegaly is associated with increased organ stiffness, peak blood flow velocity and pressure in v. lienalis, as well as periportal lymphadenopathy. Identified changes are characteristics of young patients. Conclusion. Ultrasound examination of the spleen is of high diagnostic value for patients with infectious mononucleosis allowing highly accurate assessment state of the immune organs in the acute disease period. At the preclinical stage, gradation of splenomegaly is possible depending on its intensity, assessed hemodynamics and organ stiffness.

Acute intestinal infections are widespread and hold the second place among infectious diseases, giving way solely to respiratory diseases. In this regard, much attention has been paid to examining acute intestinal infections, including immunopathogenetic mechanisms. And since proinflammatory and antiinflammatory cytokines play an important role in development of inflammatory reactions affecting disease severity and outcome, it becomes reasonable to study polymorphism of genes governing production of related molecules. Thus, the aim of our study was to examine the polymorphism in the IL-1β Т31С and IL-2 T330G genes; such mutations were characterized by nucleotide replacement affecting the gene promoters, which influenced production rate and level of the relevant cytokines. There were enrolled 108 patients with acute intestinal infections comprising main group as well as 94 apparently healthy subjects in the control group. Genomic DNA was isolated from the whole blood leukocytes by using a DNA-express-blood reagent, followed by conducting amplification reaction with two pairs of allele-specific primers. The polymorphism in the IL-1β, IL-2 genes was determined by PCR with primers purchased from Litech LLC (St. Petersburg). Data processing was carried out by using the statistical Statistica 6 suite software. While assessing the carriage rate of IL-1β T31C gene polymorphic markers by using the multiplicative inheritance model in both groups, the prevalence of the normal T allele and, respectively of the —31TT and —31TC genotypes with OR = 1.83 and an interval of 1.04—3.22 (χ² = 6.35, p = 0.04, df = 2) was found, which allowed us to identify a relationship between the carriage of IL-1β в gene heterozygous variant and potentially elevated risk of AII. Regarding the IL-2 T330G gene, it was found that pathological G alleles was more markedly abundant in patients with acute intestinal infections compared to control group. Analyzing diverse IL-2 T330G carriage rate in patients with acute intestinal infections revealed that carriers of the TG heterozygous variant predominated — 56.48% (χ² = 17.75, F = 0.000031), whereas pathological genotype GG was found in 13.89% (χ² = 12.31, F = 0.000663, p < 0.05), with high probability of the relationship between carriage of these genotypes and a risk of disease development (OR — 3.63 [1.97—6.68] and OR — 6.91 [2.12—22.59]). Hence, the carriage of polymorphic variants of the IL-1β T31C and IL-2 T330G genes was associated with elevated risk of developing AII in case of infection with pathogenic microorganisms.

The aim of the study was to assess the measles immunity level among employees of medical organizations of various specialties, young subjects, and neonates. Materials and Methods. The measles immunity status was assessed for all the employees of St. Petersburg State Budgetary Healthcare Institution Maternity Hospital No. 10 (386 subjects), civilian medical staff of the clinics of the Military Medical Academy named after S.M. Kirov (Military Medical Academy) (1399 subjects), cadets of the Military Medical Academy (304 subjects) and 34 neonates. Laboratory testing was performed by using ELISA with test kits “VektoKor-IgG” (RF). Results. Medical workers displayed high total level of protection against measles virus serologically confirmed in 87.5% of the maternity hospital staff and 81.6% of the employees at the Military Medical Academy clinics. No differences in the immune status between the varying categories of medical personnel from the departments of various specialties were revealed. Lower population immunity was observed in the 20-40-year age group. Among the employees of the maternity hospital, the proportion of measles virus seropositive subjects aged 20—40 years was 75.9% (95%, CI 67.2—82.9%), 40—59 years — 91.5% (95%, CI 86.7—94.7%), 60 year and older subjects were all seropositive (95%, CI 94.6—100%). Dual vaccination did not guarantee emergence of effective measles immunity. The majority of seronegative subjects were dually vaccinated, hence, even in case of previous dual measles vaccination, it is necessary to perform a serological examination prior to recruitment to medical facilities. Females comprised more than 90% of medical workers. Therefore, women of fertile age previously dually vaccinated, but immunologically seronegative, are at risk of measles and intrauterine fetal infection, as well as the risk of its development is increased in vaccination age children. It was confirmed by demonstrating that as few as 70.6±15.3% of neonates were immune to the measles virus. The proportion of seronegative infants (29.4±15.3%) was comparable to that one in seronegative subjects aged 20—40 years (24.1±8.1%) working at the maternity hospital. Among the younger age group (aged 18—23 years) such as cadets of the Military Medical Academy, a significantly higher proportion of seronegative individuals was found — 48.3±5.6%, thereby increasing probability for measles outbreak therein. Conclusions. In order to eradicate measles, it is necessary to develop a screening program for detecting antibodies against measles among young and middle-aged subjects.

The study's purpose was the developing of the method for Acinetobacter nosocomialis bacteria identification by the totality of phenotypic characteristics of the Acinetobacter baumannii (Ab) group based on the urease activity trait.

The research's objects were clinical strains of the Ab group, isolated in 2018—2019 in the bacteriological laboratory of Kirov Military Medical Academy (St. Petersburg), of which were A. baumannii (n = 85), A. nosocomialis (n = 12), A. pittii (n = 10). In addition, 9 strains of A. nosocomialis were isolated from water samples from the Neva River and 2 strains of A. calcoaceticus from the cyanobacterial mats. The belonging of the strains to Ab group was determined by the combination of the metabolic and physiological characteristics of the taxonomic tests for this group. The species identification of the studied strains was determined by the matrix-associated laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). The urease activity of bacteria was determined using the microvolume method. We used a medium with urea in the following composition (g/l): Na₂HPO₄ — 1.1; KH₂PO₄ — 1.1; NaCI — 5.0; 40% alkaline solution phenol red — 5 ml; urea — 10—15; distilled water — 1 l. The ingredients, without urea, were dissolved in distilled water, dispensed to vials, sterilized for 20 minutes at 121°C, urea was added in the calculated amount. The medium with urea was added in 0.1 ml to wells of the plate, then inoculated the daily agar culture of the studied and control strains by full loop (2 mm in diameter) and incubated under aerobic conditions at 37°C. The reaction results for a rapid urease activity were determined after 3 hours by a change in the initial color of the medium. The reactions were accounted after 7—24 hours to detect activity urease. It was found that 100% of A. nosocomialis strains and 18.82% of A. baumannii strains had urease activity. At the same time, high activity urease was found only in one strain of A. baumannii (1.17%) and in all strains of A. nosocomialis. Therefore, the presence of high urease activity is of taxonomic importance for the species A. nosocomialis as the marker of distinguishing this species from other bacteria species of the Ab group. The sensitivity and specificity of the identifying A. nosocomialis strains by suggested approach compared to the studied strains identification by MALDI-TOF MS were 100 and 98.83% (x² = 103.2; p < 0.0001), respectively.