Modulation of gut microbiota with probiotics as a strategy to counteract endogenous and exogenous neurotoxicity

The existing data demonstrate that probiotic supplementation affords protective effects against neurotoxicity of exogenous (e.g., metals, ethanol, propionic acid, aflatoxin B1, organic pollutants) and endogenous (e.g., LPS, glucose, Aβ, phospho-tau, α-synuclein) agents. Although the protective mechanisms of probiotic treatments differ between various neurotoxic agents, several key mechanisms at both the intestinal and brain levels seem inherent to all of them. Specifically, probiotic-induced improvement in gut microbiota diversity and taxonomic characteristics results in modulation of gut-derived metabolite production with increased secretion of SFCA. Moreover, modulation of gut microbiota results in inhibition of intestinal absorption of neurotoxic agents and their deposition in brain. Probiotics also maintain gut wall integrity and inhibit intestinal inflammation, thus reducing systemic levels of LPS. Centrally, probiotics ameliorate neurotoxin-induced neuroinflammation by decreasing LPS-induced TLR4/MyD88/NF-κB signaling and prevention of microglia activation. Neuroprotective mechanisms of probiotics also include inhibition of apoptosis and oxidative stress, at least partially by up-regulation of SIRT1 signaling. Moreover, probiotics reduce inhibitory effect of neurotoxic agents on BDNF expression, on neurogenesis, and on synaptic function. They can also reverse altered neurotransmitter metabolism and exert an antiamyloidogenic effect. The latter may be due to up-regulation of ADAM10 activity and down-regulation of presenilin 1 expression. Therefore, in view of the multiple mechanisms invoked for the neuroprotective effect of probiotics, as well as their high tolerance and safety, the use of probiotics should be considered as a therapeutic strategy for ameliorating adverse brain effects of various endogenous and exogenous agents.

Role of gut microbiota in the modulation of the health effects of advanced glycation end‑products (Review)

The aim of the present review was to summarize the potential interactive effects between the gut microbiota and advanced glycation end‑product (AGE) accumulation and toxicity in the host, and to reveal potential the mediatory effects of the gut microbiota on AGE‑related health effects. The existing data demonstrate that dietary AGEs can have a significant impact on the richness and diversity of the gut microbiota, although the particular effect is dependent on the type of species, as well as the exposure dose. In addition, the gut microbiota may metabolize dietary AGEs. It has been also demonstrated that the characteristics of the gut microbiota, including its richness and relative abundance of certain taxa, is tightly associated with AGE accumulation in the host organism. In turn, a bilateral interplay between AGE toxicity and the modulation of the gut microbiota may contribute to pathogenesis of ageing and diabetes‑associated diseases. Bacterial endotoxin lipopolysaccharide appears as the molecule that mediates the interactions between the gut microbiota and AGE toxicity, specifically via the modulation of the receptor for AGE signaling. Therefore, it is proposed that the modulation of the gut microbiota using probiotics or other dietary interventions may have a significant impact on AGE‑induced glycative stress and systemic inflammation.

Gut Microbiota as a Mediator of Essential and Toxic Effects of Zinc in the Intestines and Other Tissues

The objective of the present study was to review the existing data on the association between Zn status and characteristics of gut microbiota in various organisms and the potential role of Zn-induced microbiota in modulating systemic effects. The existing data demonstrate a tight relationship between Zn metabolism and gut microbiota as demonstrated in Zn deficiency, supplementation, and toxicity studies. Generally, Zn was found to be a significant factor for gut bacteria biodiversity. The effects of physiological and nutritional Zn doses also result in improved gut wall integrity, thus contributing to reduced translocation of bacteria and gut microbiome metabolites into the systemic circulation. In contrast, Zn overexposure induced substantial alterations in gut microbiota. In parallel with intestinal effects, systemic effects of Zn-induced gut microbiota modulation may include systemic inflammation and acute pancreatitis, autism spectrum disorder and attention deficit hyperactivity disorder, as well as fetal alcohol syndrome and obesity. In view of both Zn and gut microbiota, as well as their interaction in the regulation of the physiological functions of the host organism, addressing these targets through the use of Zn-enriched probiotics may be considered an effective strategy for health management.

Zinc and respiratory tract infections: Perspectives for COVID‑19 (Review)

In view of the emerging COVID‑19 pandemic caused by SARS‑CoV‑2 virus, the search for potential protective and therapeutic antiviral strategies is of particular and urgent interest. Zinc is known to modulate antiviral and antibacterial immunity and regulate inflammatory response. Despite the lack of clinical data, certain indications suggest that modulation of zinc status may be beneficial in COVID‑19. In vitro experiments demonstrate that Zn2+ possesses antiviral activity through inhibition of SARS‑CoV RNA polymerase. This effect may underlie therapeutic efficiency of chloroquine known to act as zinc ionophore. Indirect evidence also indicates that Zn2+ may decrease the activity of angiotensin‑converting enzyme 2 (ACE2), known to be the receptor for SARS‑CoV‑2. Improved antiviral immunity by zinc may also occur through up‑regulation of interferon α production and increasing its antiviral activity. Zinc possesses anti‑inflammatory activity by inhibiting NF‑κB signaling and modulation of regulatory T‑cell functions that may limit the cytokine storm in COVID‑19. Improved Zn status may also reduce the risk of bacterial co‑infection by improving mucociliary clearance and barrier function of the respiratory epithelium, as well as direct antibacterial effects against S. pneumoniae. Zinc status is also tightly associated with risk factors for severe COVID‑19 including ageing, immune deficiency, obesity, diabetes, and atherosclerosis, since these are known risk groups for zinc deficiency. Therefore, Zn may possess protective effect as preventive and adjuvant therapy of COVID‑19 through reducing inflammation, improvement of mucociliary clearance, prevention of ventilator‑induced lung injury, modulation of antiviral and antibacterial immunity. However, further clinical and experimental studies are required.

A Low-Molecular-Weight Compound Derived from Human Leukocytes Determines a Bactericidal Activity of the Interferon Preparation

The aim of this study was to characterize the structure and mode of action of antimicrobials derived from a commercial preparation of alfa-interferon. By combination of semi-preparative/analytical reversed-phase high-performance liquid chromatography, we isolated and purified a novel active substance based on carbohydrate with a complex of amino acids, which determines antimicrobial property of commercial preparation of interferon. A size-exclusion chromatography was performed and LC/ESI-MS revealed molecular masses of active substance were in the range of 180-249 Da. Edman sequencing identified phenylthiohydantoin (PTH) derivatives which consisted a set of preliminary (Asp, Glu, Gly, and Ala) and minor amino acids (Leu and Thr) at equimolar ratio. Thus, the purified active substance is a compound containing the complex of amino acids connected with carbohydrate background and called leucidin. Leucidin demonstrated antimicrobial activity against the model Escherichia coli (E. coli) K12 strain at a minimal inhibitory concentration of 20 μg mL^-1. The revealed antimicrobial mechanism of action is associated with violation of the bacterial cell wall leading to a SOS response and bacterial autolysis. Despite the preliminary nature of the results, obtained data allowed us to discover the previously unknown leukocyte-derived antimicrobial molecules.

Electronic structure and charge transport in nonstoichiometric tantalum oxide

The atomic and electronic structure of nonstoichiometric oxygen-deficient tantalum oxide TaO _x<2.5 grown by ion beam sputtering deposition was studied. The TaO _x film content was analyzed by x-ray photoelectron spectroscopy and by quantum-chemistry simulation. TaO _x is composed of Ta₂O₅, metallic tantalum clusters and tantalum suboxides. A method for evaluating the stoichiometry parameter of TaO _x from the comparison of experimental and theoretical photoelectron valence band spectra is proposed. The charge transport properties of TaO _x were experimentally studied and the transport mechanism was quantitatively analyzed with four theoretical dielectric conductivity models. It was found that the charge transport in almost stoichiometric and nonstoichiometric tantalum oxide can be consistently described by the phonon-assisted tunneling between traps.

Electronic structure of stoichiometric and oxygen-deficient ferroelectric Hf0.5Zr0.5O2

The electronic structure of oxygen-deficient Hf_0.5Zr_0.5O₂ in the non-centrosymmetric orthorhombic (ferroelectric) phase was investigated by means of x-ray photoelectron spectroscopy and first-principle density functional theory calculations. It was established that a peak in the photoelectron spectra observed at an energy above the valence band top of ferroelectric Hf_0.5Zr_0.5O₂ in ion-etched samples was due to oxygen vacancies. A method for evaluating the oxygen vacancies concentration in the material from the comparison of experimental and theoretical photoelectron spectra of the valence band is proposed. It is found that oxygen polyvacancies are not formed in ferroelectric Hf_0.5Zr_0.5O₂: an energy-favorable spatial arrangement of several oxygen vacancies in the crystal corresponds to the configuration formed by noninteracting vacancies distant from each other. The oxygen vacancies in five charged states were simulated. The electron levels in the bandgap caused by charged oxygen vacancies indicate that any type of oxygen vacancies in ferroelectric Hf_0.5Zr_0.5O₂ can capture both electrons and holes, i.e. can act as an amphoteric localization center for charge carriers.

Gut as a target for cadmium toxicity

The primary objective of the present study was to review the impact of Cd exposure on gut microbiota and intestinal physiology, as well as to estimate whether gut may be considered as the target for Cd toxicity. The review is based on literature search in available databases. The existing data demonstrate that the impact of Cd on gut physiology is two-sided. First, Cd exposure induces a significant alteration of bacterial populations and their relative abundance in gut (increased Bacteroidetes-to-Firmicutes ratio), accompanied by increased lipopolysaccharide (LPS) production, reflecting changed metabolic activity of the intestinal microbiome. Second, in intestinal wall Cd exposure induces inflammatory response and cell damage including disruption of tight junctions, ultimately leading to increased gut permeability. Together with increased LPS production, impaired barrier function causes endotoxinemia and systemic inflammation. Hypothetically, Cd-induced increase gut permeability may also result in increased bacterial translocation. On the one hand, bacteriolysis may be associated with aggravation of endotoxemia. At the same time, together with Cd-induced impairment of macrophage inflammatory response, increased bacterial translocation may result in increased susceptibility to infections. Such a supposition is generally in agreement with the finding of higher susceptibility of Cd-exposed mice to infections. The changed microbiome metabolic activity and LPS-induced systemic inflammation may have a significant impact on target organs. The efficiency of probiotics in at least partial prevention of the local (intestinal) and systemic toxic effects of cadmium confirms the role of altered gut physiology in Cd toxicity. Therefore, probiotic treatment may be considered as the one of the strategies for prevention of Cd toxicity in parallel with chelation, antioxidant, and anti-inflammatory therapy.

Influence of Plantaginaceae species on E. coli K12 growth in vitro: Possible relation to phytochemical properties

CONTEXT

The data concerning the influence of Plantaginaceae water extracts on bacterial growth are contradictory.

OBJECTIVE

This study investigates the influence of Plantago maxima Juss. ex Jacq., Plantago lanceolata L., Plantago major L., Veronica teucrium L., Veronica spicata L., and Veronica incana L. aqueous extracts on growth of Escherichia coli K12 culture and the relation to antioxidant, reducing, and iron-binding activities.

MATERIALS AND METHODS

Aqueous extracts were prepared from the dried leaves with the final concentration of 1/10, 1/15, 1/20, 1/25, 1/30, 1/35, and 1/40 (w/w). Comparative analysis of total flavonoids, iridoids, and tannins in Plantaginaceae species was performed. Iron-binding, antioxidant, and reducing activities of plant extracts were analyzed spectrophotometrically. The influence of plant extracts on E. coli K12 growth was studied in vitro by estimating the bacterial growth in the extract-containing medium.

RESULTS

Total tannin content in plant leaves positively correlated with iron-binding activity (r = 0.641), whereas total flavonoids correlated with antioxidant activity (r = 0.687). In an in vitro model, it is estimated that water extracts of studied Plantaginaceae species stimulated bacterial growth. Prebiotic activity significantly of 1/20 and 1/40 plant extracts positively correlated with antioxidant (r = 0.589; r = 0.576, respectively) and reducing activity (r = 0.721; r = 0.620, respectively) of plant aqueous extracts at 6-24 h. Negative correlation was observed between iron-binding activity and bacterial growth (r = -0.503 and r = -0.534 for 1/20 and 1/40 extracts, respectively).

CONCLUSION

Aqueous Plantaginaceae extracts possess prebiotic activity depending on the phytochemical content of plant leaves.

The Effect of Brief Exposure to Sub-Therapeutic Concentrations of Chlorhexidine Digluconate on the Susceptibility of Staphylococci to Platelet Microbicidal Protein

BACKGROUND

Antiseptic agents are widely used in hospitals and are essential when prevention and control of nosocomial infections is required. It is necessary to consider several aspects that affect the biocide activity because they have direct impact on the nosocomial infection rate. Organisms belonging to the Staphylococcus genus are involved in such infections and chlorhexidine digluconate (CHXD) is one of the most used antiseptic agents for human and animal health. In the context of such infections, anti-bacterial peptides have been isolated from platelets and have been termed platelet microbicidal proteins (PMP). Platelet microbicidal proteins have been shown to enhance the bacterial inhibitory activities of sub-therapeutic concentrations of antibiotics. The main objective of this study was to investigate the effect of brief exposure to different sub-therapeutic concentrations of CHXD on the susceptibility of staphylococci to PMP.

METHODS

The influence of brief exposure to three different sub-therapeutic concentrations of CHXD (0.005%, 0.0025%, and 0.00125%) on the subsequent staphylocidal effect of PMP was evaluated.

RESULTS

Among all clinical staphylococcal strains studied, all isolates were considered to be resistant to the bactericidal action of PMP. Exposure of staphylococci to CHXD prior to PMP resulted in significantly increased staphylococcal killing compared with the killing achieved with PMP alone. This enhanced effect was most marked for concentrations of CHXD of 0.005%.

CONCLUSION

The combined data indicate that PMP exerts cooperative bactericidal effect with CHXD. The anti-staphylococcal PMP and CHXD synergistic activity in vitro demonstrated in the present study make these molecules potentially useful for preventing endovascular catheter-associated infections. Future research based on animal and human models is needed to elucidate the in vivo efficacies and toxicities and utility in clinical practice.

[Effect of thrombodefensins on the course of chronic staphylococci dermatitis on in vivo model]

AIM

Evaluate therapeutic effect of thrombodefensins (TD) on the course of chronic staphylococci dermatitis (CSD) in mice.

MATERIALS AND METHODS

TD was obtained from human thrombocytes. 24 CBRB-Rb(8.17)1Iem line female mice were used in the experiment, that were divided into 2 equal groups. Staphylococcus aureus strain producing exfoliative exotoxin was isolated from withers of each mouse with signs of affection. Mice of the experiment group subcutaneously around the locus of affection, received for 4 weeks daily a composition in the volume of 0.2 ml, that contains 1 g of dry lyophilized TD diluted in 10 ml of 0.9% NaCl (final concentration of the preparation--15 μg/ml). Control group animals similarly received 0.9% solution of NaCl without TD. Area and degree of the affected zone on the back was evaluated in all the mice. Statistical significance of differences in the values of parameters was determined by t-criteria.

RESULTS

At the start of the experiment the average area of the affected zone in mice of both groups was 167 ± 17 mm2. From day 8 to 23 the expansion of the affection zone was observed, however in the experiment group of mice these negative tendencies were less pronounced. At the end of the experiment on day 50 the area of affection was significantly smaller (2.3 times) in the experiment group of mice compared with the control (p < 0.05).

CONCLUSION

The anti-staphylococci effect of TD, demonstrated in the study, opens perspective of their clinical use in CSD therapy.

[Species structure and staphylococci bioprofile characteristics--ausative agents of perinatal infectious-inflammation pathology in children of Orenburg]

AIM

Analysis of taxonomic structure and bioprofile of staphylcocci--causative agents of cutaneous and ophthalmic forms of perinatal infectious-inflammation pathology (IIP) in Orenburg neonates.

MATERIALS AND METHODS

Bacteriologic study in 308 neonates with clinical signs of cutaneous and ophthalmic forms of perinatal IIP was carried out with isolation of microorganisms from lesions and their species (genus) identification by generally accepted methods. The presence of hemolytic, anti-lysozyme, activity, ability to form biofilms, resistance to antimicrobial cationic peptides of human leukocytes (intercid) and thrombocytes (trombodefensins), sensitivity to antibiotics were determined in the isolated staphylococci strains.

RESULTS

Staphylococci dominated in the structure of causative agents of cutaneous and ophthalmic forms of perinatal IIP (76.2%) and among those coagulase-negative staphylococci had a priority position (82.4 ± 3.4%). Staphylococci had a distinctive pathogenic potential and frequently had antibiotic resistance.

CONCLUSION

Perinatal IIP is examined as a variant of endogenous bacterial infection. The necessity of microbiologic monitoring for development of effective approaches to therapy and prophylaxis of perinatal IIP is justified.

[The comparative characteristics of antibacterial properties of the peptides of the active site of GM-CSF, and substances delivered from supernatants of hematopoietic progenitor CD34+45- cells]

The antibacterial activity of synthetic peptides of the active site of GM-CSF and supernatants of CD34+45- hematopoietic progenitor cells has been investigated GM-CSF peptides and cell supernatants were found to possess pronounced antibacterial activity, at that a combination of these substances has a more pronounced activity in comparison with the single substances. Possible mechanisms of the identified effects of synthetic peptides and substances from the supernatants of CD34+5- cells are discussed.

Phenotypic differences between coagulase-negative staphylococci isolated from seminal fluid of healthy men and men suffering from chronic prostatitis syndrome

Chronic prostatitis syndrome (CPS) is a common urologic condition that many clinicians find difficult to diagnose and treat effectively. The most common causative agents of CPS among Gram-positive bacteria are coagulase-negative staphylococci (CNS). We compared phenotypic properties among CNS isolated from semen of healthy men and patients with CPS. A significantly higher proportion of CPS strains demonstrated inhibition of lysozyme and platelet microbicidal protein. Identifying these phenotypic characteristics in clinical laboratories would be helpful to differentiate which staphylococcal bacteriospermia case should be treated and which should not.

[Role of persistence characteristics of microorganisms in pathogenesis of endogenous infections]

Definition of endogenous bacterial infections (EBI) is formulated as well as their nosological variability is demonstrated and clinical and microbiological characteristics are characterized. Universal scheme of pathogenesis of these infections with separation of key phases of their course: premorbid phase, colonization, alteration, sanation or persistence. Important role of persistence characteristics of microorganisms for the development of EBI, which provide survival of agents during contacts with humoral and cellular effectors of host's immunity, is substantiated.

Distribution of secretory inhibitor of platelet microbicidal protein among anaerobic bacteria isolated from stool of children with diarrhea

AIM: To study the secretory inhibitor of platelet microbicidal protein (SIPMP) phenotypes of faecal anaerobic isolates from patients with diarrhea.

METHODS: Faecal isolates of anaerobic bacteria (B. fragilis, n = 42; B. longum, n = 70; A. israelii, n = 21; E. lentum, n = 12) from children with diarrhea were tested. SIPMP production was tested by inhibition of platelet microbicidal protein (PMP) bioactivity against B. subtilis and was expressed as percentage of inhibition of PMP bactericidal activity.

RESULTS: Among anaerobic isolates 80% of B. longum strains, 85.7% of A. israelii strains, 50% of E. lentum strains and 92.86% of B. fragilis strains were SIPMP-positive. The isolated anaerobic organisms demonstrated SIPMP production at a mean level of 13.8% ± 0.7%, 14.7% ± 1.8%, 3.9% ± 0.9% (P < 0.05) and 26.8% ± 7.5% (P < 0.05) for bifidobacteria, A. israelii, E. lentum and B. fragilis, respectively.

CONCLUSION: Data from the present study may have significant implications in understanding the pathogenesis of microecological disorders in the intestine, as well as for future improvement in the prevention and therapy of anaerobe-associated infections.

Distribution of secretory inhibitor of platelet microbicidal protein among urethral isolates with its correlation with prostatitis

AIM

To report the detection in vitro of secretory inhibitor of platelet microbicidal protein (SIPMP) phenotypes of urethral isolates along with a comparison with isolates from patients with or without chronic bacterial prostatitis (CBP).

METHODS

Urethral isolates of Staphylococcus spp. (n=4), diphtheroids (n=28), micrococci (n=15), streptococci (n=21), Enterobacteriaceae (n=9) and Enterococcus faecalis (n=19) from patients with or without CBP were tested. SIPMP production was tested by inhibition of platelet microbicidal protein (PMP) bioactivity against Bacillus subtilis and was expressed as percentage of inhibition of PMP bactericidal activity.

RESULTS

A significantly higher proportion of CBP-strains (57.78% vs. 16.67%) reduced PMP-induced killing of Bacillus subtilis than non-CBP strains did (P<0.01). SIPMP levels of staphylococci and Enterococcus faecalis from the CBP group were significantly higher than those of the control group.

CONCLUSION

These results suggest that SIPMP production is associated with the CBP source. Data from the present study might have significant implications for the understanding of the pathogenesis of CBP.

Staphylococcal secretory inhibitor of platelet microbicidal protein is associated with prostatitis source

This study reports the detection of an extracellular staphylococcal product, designated secretory inhibitor of platelet microbicidal protein (SIPMP), that causes local inhibition of the bactericidal action of platelet microbicidal protein (PMP) in the fluid phase. Urethral isolates of Staphylococcus aureus (n=24) and coagulase-negative staphylococci (CNS) (n=47) from patients with or without chronic bacterial prostatitis (CBP) were tested. SIPMP production was tested by inhibition of PMP bioactivity against Bacillus subtilis and was expressed as percentage inhibition of PMP bactericidal activity. The PMP susceptibility of staphylococcal strains was determined by exposing bacterial cells to serial dilutions of PMP. Staphylococci from patients without CBP produced SIPMP at levels of 10.3+/-1.2 and 13.25+/-1.72 % for S. aureus and CNS, respectively. Strains isolated from men with CBP inhibited PMP-induced killing of B. subtilis by 23.38+/-4.2 % (P<0.05) and 23.69+/-1.87 % (P<0.01) for S. aureus and CNS, respectively. SIPMP production correlated with staphylococcal resistance to PMP (r2=0.6082 and 0.7264 for S. aureus and CNS, respectively). SIPMP represents a hitherto unrecognized determinant of staphylococcal pathogenicity. These results suggest that SIPMP production is associated with the CBP source. Data from this study may have significant implications for the understanding of the pathogenesis of CBP.

[Physico-chemical properties of staphylococci of different species in resistance to human thrombodefensins]

Testing 54 strains of staphylococci (Staphylococcus aureus, S. epidermidis, S. haemolyticus, S. warneri, S. hominis, S. capitis) revealed that S. aureus in contrast to coagulase-negative staphylococci (CNS) is more resistant to bactoriocidal action of human thrombodefensins (resistance index: 60.3 vs 25.6%), less hydrophilicolipophilic balance-HLB: -0.42 vs -0.64) and less charged (x-potential: -32.4 vs -35.6 mV). In groups of staphylococci (S. aureus and CNS) correlation links of bacterial resistance to human thrombodefensins with their HLB and x-potential (r=-0.32...-0.36). By In vitro experiments, it was shown that 5 passages of staphylococci in meat-peptonic broth with human thrombodefensins (50 mkg protein/ml) lead to adaptation of bacteria followed by the formation of resistance to cationic peptides from thrombocytes, a decrease of hydrophobicity and x-potencial. The role of physico-chemical properties in providing thrombodefensin-resistance of staphylococci as a developmental factor of infectious-and-inflammatory process and persistence of bacteria was confirmed with Salmonella infection.

[Taxonomic spectrum and antibiotic resistance of Enterobacteriaceae isolated from bile of patients with cholangitis]

The data on the taxonomic structure and antibiotic resistance of Enterobacteriaceae isolated from bile of patients with various clinical variants of cholangitis are presented. It was shown that bacteriocholia was registered in 53.3-90.9% of the patients during operations and in 88.9-100% of the patients during the postoperative period. Among bilicultures enterobacteria dominated (93.4% of the cases) with predominance of E. coli and Klebsiella spp. (the total about 70%). The enterobacteria isolates were frequently resistant to ampicillin and amoxycillin/clavulanate (92.6 and 70.4% of the strains respectively), gentamicin and amikacin (74.1 and 22.2%), cefazolin and cefotaxime (88.9 and 37.0%). The resistance to imipenem and ciprofloxacin (7.4%) was rare, that should be considered while prescribing drugs for empirical antimicrobial chemotherapy.

[Taxonomic characterization and antibiotic resistance of pathogens of perinatal infectious inflammatory pathology in infants in Orenburg]

The materials on regional features of the nosologic structure, taxonomic spectrum and antibiotic resistance of the pathogens of perinatal infectious inflammatory pathology (IIP) in infants in Orenburg are presented. From 2002 to 2005 the average level of IIP of 19.0 cases per 1000 living new borns and the dominance of skin inflammatory diseases (vesiculopustulosis in particular) in the nosologic structure among the other forms of IIP (including conjunctivitis and pneumonia) were observed. The prevalence of the gram positive cocci with the leadership of coagulase negative staphylococci among the skin and eye forms of IIP was shown. Their portion reached 62.8%. The portion of the other microorganisms was much lover. Gramnegative bacteria (Neisseria spp., E. coli, K. ozaenae) were isolated from 6.1, 4.3 and 0.6% of the cases. The Candida isolates were detected in 1% of the cases. The regional antibiotic resistance register for the pathogens of IIP was developed. Its use is obligatory in prescribing drugs for empirical therapy of such pathology and prevention of its complications.

[Properties of Staphylococcus aureus in case of the unfavorable course of burn infection]

Clinical and microbiological study of wound discharge from 35 patients demonstrated a relationship between biological properties of S. aureus, the causative agent of burn infection, and the course of the infected burn trauma. The prognostic importance of the antioxidant properties of these staphylococci was established: in cases of the unfavorable course of the burn process they showed essentially greater resistance to peroxinitrite and higher superoxide dismutase activity in comparison with the cultures isolated from patients with uncomplicated wound infection.

[Comparative analysis of the sensitivity of enterobacteria to bile]

The analysis of the sensitivity of 195 enterobacterial cultures to bile revealed that their level of resistance decreased in the following row: Shigella > Salmonella > Klebsiella > Escherichia > Providencia. As shown on a sample of 136 E. coli isolates the level of resistance of these bacteria to bile depended on their isolation source: in E. coli isolated from bile in cholecystitis, from urine in pyelonephritis and from feces in intestinal dysbacteriosis resistance was 1.1-1.3 times higher than in E. coli isolated from the water of open reservoirs, from the feces of healthy persons and from extraintestinal foci of purulent inflammation. The level of sensitivity to bile is regarded as a property making it possible for enterobacteria to colonize biliary tracts and the proximal sections of the digestive tract.

[Characteristics of enterobacteria isolated from patients with urogenital pathology]

Species composition and a number of persistence characteristics enterobacteria isolated from urine of 42 pregnant and 22 nonpregnant women with pyelonephritis (relapse, remission), from prostatic fluid of 225 males and secretions of cervical canal of 124 women with urogenital pathology (prostatitis, salpingo-oophoritis) were studied. The study revealed that enterobacteria, including Escherichia coli, prevailed in the structure of uromicroflora (66.7-83.3%) and constituted a relatively small proportion among "genital" isolates of microorganisms (19.9-22.2%). Male and female sterility and the presence of enterobacteria in the reproductive tract of patients were found to be directly correlated. Clinical isolates of enterobacteria were shown to possess pronounced seroresistance and the complex of persistence characteristics, including antilysozyme, anti-intercidal and anticomplementary activity.

[Ecovariant differences of Escherichia coli strains with respect to colicinogenicity and colicin resistance]

The analysis of 173 Escherichia coli strains, isolated from different sources, for colicinogenicity and colicin resistance revealed that frequency of these signs increased in the following order: water in open reservoirs, intestine, extraintestinal localizations. In most cases resistance to 5 or more bacterial colicins was due to the absence of the corresponding receptors to colicins. Colicin resistance and colicinogenicity render E. coli selective advantages under the conditions of intestinal microbiocenosis.

[Resistance of Escherichia coli to "Intercid", a leukocyte cation protein]

In vitro experiments on 120 E. coli strains isolated from different sources (43 from water, 22 from the feces of healthy persons, 55 from patients with extraintestinal E. coli infections) have demonstrated that some of E. coli isolated, mainly the causative agents of extraintestinal infections, are resistant to the antibacterial action of "intercid" and have anti-Intercid activity (AIA) and a high level of antilysozyme activity. The use of the correlation and two-factor analyses has made it possible to establish the relationship between these characteristics and to find out an even more important contribution of AIA to the determination of bacterial Intercid-resistance (fusion force h2 = 13.1-25.0%). Experiments on E. coli isogenic variants with phenotypes AIA+ and AIA- have shown that AIA is an additional factor which determines the resistance of E. coli to "intercid".

[The ecological and medical aspects of the symbiosis between Escherichia coli and man]

In this work different variants of the symbiosis of E. coli with a human body are analyzed, and the symbiotic relationships between them are shown to follow the type mutualism, commensalism, parasitism and habitation. The authors emphasize that the multiplicity of variants of bacteria-host relationships is based on the phenotypic polymorphism of E. coli clones (clone lines). Taking into account their ecological (symbiotic) features and biomedical importance, all E. coli clones are divided into 4 groups (clusters): mutualists as nonpathogenic organisms; commensals as potential pathogens (causing extraintestinal E. coli infections); parasites as real pathogens (causing acute intestinal infections); "occasional" symbionts of man. The proposition on the cluster structure of E. coli as a species is formulated.

[The in-vitro effect of the leukocytic cationic protein preparation Intercide on Escherichia coli]

Intercide is a cationic protein with the molecular weight of 11.0-11.5 kD from human leukocytes. The in vitro effect of its different concentrations (0.6 to 1.8 mg/ml) on populations of Escherichia coli M17 and K12 and 120 E.coli isolates from various sources such as water, feces of healthy humans and patients with extraintestinal escherichiosis was studied. The experiments with the bacterial suspensions and broth cultures demonstrated that Intercide had an antibacterial action on both the stationary and growing cells. However, some strains of E.coli were resistant to the lethal effect of Intercide. It was observed for the first time that in a concentration of 1.8 mg/ml Intercide was able to stimulate the biomass growth of some E.coli strains in broth culture. The factor analysis showed that the Intercide stimulating effect was more often evident with respect to extraintestinal escherichiosis pathogens with high anti-Intercide and antilysozyme activities.

[Nonenteric escherichiosis and the problem of human reproductive health]

The contribution of nonenteric Escherichia infections (NEI) to the formation of male and female infertility is analyzed. The negative influence of NEI, and particularly pyelonephritis, on the course of pregnancy, parturition and the postnatal period is shown. The role of E. coli in the development of life-threatening meningoencephalitides, pneumonia, sepsis in newborn infants is emphasized, NEI risk factors are systematized with due regard to concrete stages in the pathogenesis of this pathology. Phenotypic differences between the causative agents of NEI and nonpathogenic and diarrhea-inducing E. coli are characterized.

[The properties of Escherichia isolated from the bodies of mice in bacterial translocation after immobilization stress]

As revealed in experiments on mice, 6-hour immobilization stress initiates the process of the translocation of intestinal flora to mesenteric lymph nodes and the blood. This process is accompanied by the infection of parenchymatous organs (the liver, the spleen, the kidneys, the lungs) and the increase of the concentration of E. coli in the proximal sections of the digestive tract (the duodenum and the jejunum). As the result of the comparative analysis of the phenotypic signs of bacterial isolates obtained from intestinal and "extraintestinal" E. coli populations, the accumulation of clones with highly pronounced seroresistance and such persistence characteristics as anticomplementary and antilysozume signs, as well as resistance to the bactericidal action of leukocytic cation protein with a molecular weight of 11.0-11.5 kD, has been found to occur in the body (the blood, parenchymatous organs and the small intestine).

[The ecological determinacy of the intraspecies diversity of pathogenic bacteria]

The review deals with some theoretical and applied problems of the intraspecific diversity of pathogenic microorganisms. Special attention is given to the role of ecological factors in the formation of the phenotypic polymorphism of bacteria. The possibility of using the methods of mathematical analysis for the evaluation of the influence of the environment (ecotopes) on individual phenotypic characteristics of bacteria and their complex (bioprofile) is shown. The proposition on the bioprofile of microorganisms as a criterion of their ecological (ecotopic) marking is substantiated. The examples of using the data of the ecological marking of pathogenic bacteria in clinical epidemiology and ecological practice are presented.

[Phasic changes in reproductive potential, intracellular polyamines and antilysozyme activity in Escherichia coli in periodic culture]

Growth-phase associated changes in and relationships between the specific growth rate (mu) characterizing the reproductive capacity of the cells, the contents of intracellular biogenic polyamines (BPA), such as putrescine (P), cadaverine (C), and spermidine (S), and antilysozyme activity (ALA) were studied in 37 strains of Escherichia coli grown in batch culture on solid medium. A decrease in mu upon the transition of the culture to the stationary growth phase was accompanied by a decrease in the pool of free BPA, mainly P and C, and by the appearance of ALA. The interrelations between the parameters studied were described as a complex of direct and negative correlations; the combination of low initial P and C contents, reduced P/S and C/S ratios, and a high level of ALA was designated as a factor of slight inhibition of E. coli reproduction. It is argued that BPA and ALA are integrated in a system controlling both the metabolism and stability of peptidoglycan in E. coli.

[The seroresistance of enterobacteria isolated from different sources]

395 representatives of the family Enterobacteriaceae, isolated from household and drinking water, from healthy and sick persons, were used as an example to demonstrate that their seroresistance was greatly connected with the type of the source from which these bacteria had been isolated. Experiments showed the phenotypic conversion of Escherichia coli towards an increase in their seroresistance on contact with human blood serum. The study revealed the pleiotropic effect produced by the action of serum on a number of other properties, responsible for survival in a macroorganism (anticomplement and antilysozyme activities, adhesive capacity and hydrophobic properties of the outer surface).

[An analysis of the interrelation of antilysozyme activity and reproductive function in escherichiae]

In vitro experiments on 72 E. coli strains showed the presence of relationship between the level of their antilysozyme activity and a number of parameters of the reproduction of these bacteria. The factor analysis revealed the integration of the antilysozyme sign with the factors which determined the inhibition of the development of bacterial populations at early stages and controlled the accumulation of bacterial biomass. The study established that the beginning of the expression of the antilysozyme sign of E. coli was associated with the transition of the culture to the phase of slow growth, and the subsequent dynamics of the level of antilysozyme activity was only partially linked with the increase of biomass. The suggestion was made that the antilysozyme factor was one of the elements of the intracellular system regulating the synthesis (and/or stabilization) of peptidoglycan of bacterial cell walls.

[The characteristics of the hydrophobic properties of bacteria when interacting with blood serum]

Considerable variability of the hydrophobic properties of bacterial surface was demonstrated on 132 representatives of Escherichia coli, Neisseria, staphylococci and enterococci, belonging to museum strains and isolated from clinical material. Taxonomic and pathovariant differences in their susceptibility to hydrophobic modification induced by the thermostable and thermolabile components of blood serum were experimentally established. Extracellular bacterial products were found to be capable of preventive and restorative counteraction to such hydrophobic modifications. The antilysozyme and anticomplement activities of bacteria were shown to take part in the expression of hydrophobic/hydrophilic properties in the interaction of bacteria with blood serum.

[Role of intraspecific phenotypic diversity in the ecology of escherichia coli and staphylococcus aureus]

Investigating a complex of biological characteristics, including the inactivating ability of some antiinfectious resistance agents (lysozyme, complement, immunoglobulins, the bactericide component of interferon) in 229 and 257 E. coli and S. aureus strains, respectively, isolated from various sources has revealed the phenotypical polymorphism in the populations of these microorganisms, whose degree and specific features may be characterized by the indices of biological diversity and by the spectra of dominant biological profiles. Interpopulational variability in the bacteria was found to be determined by the specific features of their colonized ecotopes and to reflect the level of their adaptation to their inhabitance. There is a view of the organizational structure of the bacterial species as a whole complex of discrete populations of microorganisms, which include representatives of phenotypically different clone lines that occupy the optimum and some marginal econiches whose relation is supported by migration processes.

[The information value of Escherichia coli persistence markers in the bacteriological diagnosis of chronic pyelonephritis in children]

In 181 E. coli strains isolated from sick children having chronic pyelonephritis and risk factors of its development, as well as from healthy children, the complex of phenotypic signs, and among them bacterial persistence markers (antilysozyme, anticomplementary and "anti-interferon" activity), adhesive capacity, antibiotic resistance and colicinogenicity, were analyzed. The specific bioprofiles of E. coli, the causative agents of pyelonephritis, were established. The most informative biological characteristics of E. coli were determined and used as the basis for the development of the algorithm for differentiating the causative agents of pyelonephritis from transitory and contaminating flora. The effectiveness of the proposed diagnostic algorithm was confirmed by clinical approbation.

[The use of a bioprofile of Escherichia for its epidemiological marking]

The analysis of the penetrating and expressing capacity of the markers of bacterial persistence, adhesive capacity, antibiotic resistance and colicinogenicity in 254 E.coli strains of 7 groups, isolated from different ecotopes, including different environmental objects and bodies of healthy and sick children, revealed the specific character of their population bioprofiles, i.e. complexes of phenotypical signs of microorganisms. The results of the cluster analysis carried out with regard to the totality of data on E.coli bioprofiles made it possible to detect two clusters: the first cluster included pathogenic E.coli isolated from children with pathogenic processes, the second one included non-pathogenic E.coli isolated from healthy children and from aqueous objects. The levels of the information content of individual signs of microorganisms were determined and the use of E.coli bioprofiles for their epidemiological marking was substantiated.

[The immunobiological characteristics of a Salmonella typhimurium strain acquiring a plasmid that controls antibiotic resistance and antibactericidal activity]

The influence of Rdf (resistance defense factor) plasmid inherited by Salmonella typhimurium recipient strain 189, previously deprived of its own virulence plasmid of 60 MD, on the immune status of F1 (CBA x C57BL/6) mice was studied. Experimental infection induced by genetically related pairs of S. typhimurium strains, differing by the presence of Rdf plasmid, revealed the stereotypical character of changes in the number of thymic, splenic, marrow and blood cells with some variations. In mice infected by transconjugant carrying Rdf plasmid immunological shifts were, on the whole, less pronounced than those in the animals infected with clone Rdf.

[A comparative evaluation of the persistence characteristics of Escherichia isolated from different econiches]

The multiple evaluation of the persistence characteristics, including antilysozyme, anti-interferon and anticomplement activity, as well as other biological properties, such as adhesiveness, colicinogenicity and resistance to antibiotics, was carried out in 173 E. coli strains isolated from water, healthy and sick children. This evaluation revealed that each group of E. coli, depending on the source of its isolation, had its characteristic set of properties (or bioprofiles) to be analyzed, making it different from other bacterial populations. The comparative intergroup analysis showed differences between E. coli isolated from children with pathological conditions (enteric coli-bacteriosis, pyelonephritis) and E. coli isolated from water and feces of healthy children. These differences were manifested by more pronounced persistence characteristics. Dispersion analysis, having confirmed this feature, revealed that the most labile characteristics of E.coli, subject to the influence of ecological conditions, were their markers of persistence and antibiotic resistance. The results of factor analysis made it possible to unite the above mentioned properties which determined, together with adhesiveness, pathogenic potential of these bacteria.