Effects of microbial metabolites on catalase activity and growth ofStaphylococcus aureus 6538 P

The effects of cell extracts and supernatants ofLactobacillus spp. andCorynebacterium spp. on catalase activity and growth ofStaphylococcus aureus 6538 P were studied. Intra- and extracellular metabolites of lactobacilli and corynebacteria inhibited catalase activity ofS. aureus 6538 P. The growth ofS. aureus 6538 P decreased after incubation with lactobacillus metabolites. The inhibitory effect of intra- and extracellular metabolites of lactobacilli and corynebacteria on catalase activity ofS. aureus is a possible pathway of microbial interrelations responsible for the formation and/or development of microbial biocenoses. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 130, No. 7, pp. 80–82, July, 2000     

Differences in antiopsonic effects of the extracellular products ofS. aureus andN. gonorrhoeae

Extracellular products ofS. aureus andN. gonorrhoeae decrease the efficacy of opsonization of these bacteria by blood serum. Antiopsonic activity ofS. aureus exometabolites is exhibited predominantly during their contact with serum components bound to bacterial surface, which disturbed the reactions between opsonines and neutrophils, as evidenced by decreased chemiluminescent signal during phagocytosis. With gonococci, this effect was observed predominantly during preliminary contact of their extracellular products with the serum, which attenuated the intensity of opsonization. Partial parallelism between changes in the neutrophil-stimulating activity of bacterial cultures and modification of their hydrophobic properties under the effect of the studied factors cannot be regarded as an absolute relationship. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 126, No. 12, pp. 669–672, December, 1998     

Vital activity of bacteria is directly inhibitedin vitro by antibodies

The level of vital activity ofPseudomonas aeruginosa bacteria was determined according to the rate of pH decline in the culture mediumin vitro. The addition of immune serum to this medium initiated bacterial agglutination and lowered the level of vital activity of the culture. The aggregation of bacteria by centrifugation suppressed their vital activity in the same way as agglutination. Inhibition of microbial vital activity during agglutination and aggregation due to the centrifugal force may be attributed to a showing down of the rate of diffusion of nutrients and metabolites through the aggregates. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 6, pp. 662–664, June, 1995 Presented by D. S. Sarkisov, Member of the Russian Academy of Medical Sciences     

The role of opsonization ofStaphylococcus aureus in the development of local inflammation and system response

Thein vitro neutrophil-stimulating activities of twoS. aureus strains are compared with theirin vivo cytotoxic activities, including the use of intact heterologous neutrophils. After opsonization with normal autologous serum, clinical isolates ofS. aureus differ in the ability to induce luminol-dependent chemiluminescence of guinea pig peritoneal neutrophils. After opsonization, the opsonin-dependent strain markedly stimulates chemiluminescence in comparison with the opsonin-independent strain. The local inflammation induced in guinea pig by intracutaneous administration of the opsonized opsonin-dependent strain is more intense than that induced by the opsonin-independent strain. Intramuscular administration of opsonin-dependentS. aureus strain increases mortality in mice from 10 to 46% while the addition of normal guinea pig neutrophils to the inoculate has no effect on this process. Opsonization of opsonin-independent strain decreased mortality from 78 to 40%, the effect being potentiated by the addition of neutrophils to inoculate (mortality 14%). Presumably, the opsonin dependence ofS. aureus manifestedin vitro is associated with its pathogenicityin vivo, which may be caused by intense stimulation of the respiratory burst in neutrophils. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 122, No. 9, pp. 298–300, September, 1996     

Funktionen der körpereigenen Abwehr gegen Anaerobier bei Gesunden und Patienten mit chronisch-septischer Granulomatose

Summary Different strains ofBacteroides fragilis exhibit great differences in sensitivity towards serum from healthy volunteers. In the presence of 10% autologous serum, neutrophilic granulocytes and monocytes (macrophages) caused significant killing ofB. fragilis. The measured phagocytic and killing activity of the cells is comparable to their activity against aerobic bacteria (S. aureus). In four patients with chronic granulomatous disease of childhood, phagocytosis was normal but killing ofB. fragilis andS. aureus in granulocytes or monocytes (macrophages) was appreciably lowered. This malfunction of the cells was accompanied by a disturbance in oxidative metabolism and inadequate iodination after phagocytosis ofB. fragilis. The results suggest that granulocytes and monocytes play an important role in host defense against endogenous infections with anaerobes.

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Abkürzungen NBT Nitroblautetrazolium - B. fragilis Bacteroides fragilis Herrn Prof. Dr. A.K. Kleinschmidt zum 70. Geburtstag gewidmet     

Ultrastructural analysis of interactions of staphylococci with mono- and polynuclear phagocytes in nonphlogogenic and phlogogenic reaction

Antibacterial activity of neutrophils and peritoneal macrophages toward massive doses ofStaphylococcus aureus is studiedin vivo. Two types of antibacterial response are revealed: nonphlogogenic (physiological) and phlogogenic (inflammatory). Nonphlogogenic reaction is characterized by pronounced antibacterial effect of phagocytes on cocci. Transition to phlogogenic response is accompanied by impaired function of phagocytes involving their self-destruction and disintegration, which decreases their antibacterial activity and promotes inflammation.     

Development and design of a novel in vivo chamber implant for the analysis of microbial virulence and assessment of antimicrobial therapy

An accurate reflection of the pathogenicity of microorganisms and the therapeutic effects of antimicrobial agents on their growth necessitates testing within an in vivo environment. We have developed a novel diffusion chamber, incorporating two 0.22 μm membrane filters, for the growth of in vivo organisms. The chamber, which is implanted intraperitoneally into the rat, has an external sampling portal. This portal allows multiple and sequential sampling of the microbial inoculum without killing the rat, thus significantly reducing the total number of animals used in such studies. In addition, the chamber is superior to other reported implants since it is well tolerated, reusable, easily constructed and can be used within two days of implantation. Staphylococcus epidermidis and a toxic shock syndrome toxin-1 (TSST-1) producing strain of S. aureus have been successfully grown within in vivo chambers, with 10⁸–10⁹ organisms per millilitre being recovered within 48 h. Scanning electron microscopy revealed clusters of staphylococci and fibrous material adhering to the inner surface of the filters, with numerous phagocytic cells attached to the outer side. Western immunoblotting indicated that higher levels of TSST-1 were produced by S. aureus grown in vivo as opposed to cells grown in vitro.     

On the mechanisms of bacteriopyknosis

Morphological examination of primary foci several hours after intramuscular infection of rats withPseudomonas aeruginosa, Staphylococcus aureus, orStaphylococcus epidermidis showed that bacteriopyknosis is associated with deficiency of compounds necessary for the microorganisms or excess of secreted microbial metabolites. Motility is a factor of virulence, since it inhibits bacteriopyknosis. The biological significance of divalent antibodies and agglutination provided by them probably lies in considerable stimulation of bacteriopyknosis in agglutinates. Formation of IgM also enhances bacteriopyknosis. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123 No. 3, pp. 349–352, March, 1997     

Cytotoxic effects of ingested Staphylococcus aureus on bovine endothelial cells: Role of S. aureus α-hemolysin

Previously we observed that Staphylococcus aureus phagocytized by cultured bovine endothelial cells do not proliferate intracellularly, but are cytotoxic to bovine endothelial cells. To investigate S. aureus virulence factors which may be produced intracellularly and cause lysis of endothelial cells, we tested S. aureus mutants defective in production of one or more potential virulence factors and corresponding parent strains for cytotoxicity to endothelial cell monolayers subsequent to being ingested. Following incubation of endothelial cell monolayers with S. aureus for 3.5 h, cultures were supplemented with lysostaphin to destroy extracellular but not intracellular S. aureus. At subsequent times, viability of endothelial cells was assayed by retention of ³H-adenine and the number of intracellular S. aureus was measured. The cytotoxic activity of S. aureus culture supernatants was also characterized. The results indicate that S. aureus α-hemolysin is cytotoxic to bovine endothelial cells and plays an important role in the damage suffered by bovine endothelial cell monolayers following ingestion of S. aureus. Ingestion of α-hemolysin-producing S. aureus by endothelial cells in vivo might be expected to result in destruction of endothelium followed by development of platelet-fibrin vegetations. This possible sequence of events is compatible with the frequently fulminant course of S. aureus endocarditis.     

Use of 16S rRNA gene sequencing to identifyLactobacillus casei in septicaemia secondary to a paraprosthetic enteric fistula

Human infections caused byLactobacillus spp. are rarely reported in the literature. Underlying conditions are frequently reported, and identification of lactobacilli to the species level remains rare. A case ofLactobacillus casei septicaemia secondary to a vascular graft infection is reported. The 16S rRNA sequencing technique was used to definitively identifyLactobacillus casei.     

Heparan sulfate proteoglycans mediate Staphylococcus aureus interactions with intestinal epithelium

Staphylococcus aureus can be internalized by non-professional phagocytes, and may colonize the intestine in normal and antibiotic-treated individuals. Intestinal colonization may depend on the interactions of S. aureus with the intestinal epithelium. The best described mechanism of S. aureus binding to eukaryotic cells involves S. aureus fibronectin binding proteins (FnBPs), using fibronectin as a bridging molecule to β1 integrins on the eukaryotic cell surface. Because S. aureus can be internalized by enterocytes, and because S. aureus is known to bind heparan sulfate (HS), we hypothesized that heparan sulfate proteoglycans (HSPGs) widely expressed on epithelia may mediate S. aureus interactions with intestinal epithelial cells. Internalization of S. aureus RN6390 by cultured intestinal epithelial cells was inhibited in a dose-dependent fashion by the HS mimic heparin, and by HS itself. Internalization of S. aureus DU5883, which lacks expression of staphylococcal FnBPs, was also inhibited by heparin. S. aureus adherence to ARH-77 cells, transfected to express the HSPG syndecan-1, was greatly increased when compared to adherence to plasmid control ARH-77 cells which have little detergent extractable HS. In addition, compared to wild-type HS-expressing Chinese hamster ovary (CHO) cells, internalization of S. aureus was decreased using mutant CHO cells with decreased HS expression. These findings are consistent with a model wherein S. aureus internalization by intestinal epithelial cells (and perhaps other epithelia) is mediated by S. aureus binding to the HS moiety of cell-surface HSPGs, and this interaction appears independent of fibronectin binding.     

Molecular adaptation of sourdough Lactobacillus plantarum DC400 under co-cultivation with other lactobacilli

This work was aimed at investigating the molecular mechanisms of Quorum Sensing (QS) in Lactobacillus plantarum DC400 when co-cultured with other sourdough lactobacilli. The growth and survival of L. plantarum DC400 was not affected when co-cultivated with Lactobacillus sanfranciscensis DPPMA174 or Lactobacillus rossiae A7. Nevertheless, 2-DE analysis showed that the level of protein expression of L. plantarum DC400 increased under co-culture conditions. Although several proteins were commonly induced in both co-cultures, the highest induction was found in co-culture with L. rossiae A7. Overexpressed proteins, related to QS and stress response mechanisms, were identified: DnaK, GroEL, 30S ribosomal protein S1 and S6, ATP synthase subunit beta, adenosylmethionine synthetase (MetK), phosphopyruvate hydratase, phosphoglycerate kinase, elongation factor Tu, putative manganese-dependent inorganic pyrophosphatase, d-lactate dehydrogenase, triosephosphate isomerase, fructose-bisphosphate aldolase and nucleoside-diphosphate kinase. As shown by real-time PCR, expression of the luxS gene of L. plantarum DC400 was also affected during co-cultivation. According to overexpression of MetK and luxS during co-cultivation, synthesis of AI-2-like substances was also influenced by the type of microbial co-cultures.This study showed that expression of some genes/proteins, also QS-related, in L. plantarum was influenced by co-cultivation of other sourdough lactobacilli.     

Antiopsonizing effect of extracellular staphylococcal products

The ability to inhibit the opsonizing activity of immunoglobulins and the C3 component of the complement is demonstrated forStaphylococcus aureus. This ability is due to the presence of extracellular products such as the anticomplement factor and protein A. An independent and statistically significant determination of the antiopsonizing effect of these extracellular products by the given parameters is established. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 6, pp. 639–641, June, 1994 Presented by A. D. Ado, Member of the Russian Academy of Medical Sciences     

Exchange of sialic acid-containing compounds in chronic osteomyelitis

Serum content of free, oligosaccharide and protein-bound sialic acids, seromucoid components, and activity of sialidase are measured in rabbits with osteomyelitis induced by intraosteal administration ofSt. aureus. During chronic stage of purulent osteomyelitis the content of oligosaccharide-bound sialic acids is increased, while the content of seromucoid hexosamines is decreased. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 123, No. 6, pp. 701–702, June, 1997     

Microbiological criteria for assessment of ecological risk

The composition of microflora from the nasal mucosa is determined in children from 4 ecologically contrasting regions, and diagnostics of theStaphylococus carriership is performed studying the antilysozyme, antidefensin, and antihistone activity of microorganisms. It is established that the carriers ofSt. aureus strains with antihistone activity and the carriers of sporiferous bacilli predominated in ecologically unfavorable regions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 117, N ^o 6, pp. 636–638, June, 1994 Presented by A. D. Ado, Member of the Russian Academy of Medical Sciences     

Distribution of a morphogenic peptide activating the head growth of hydra in rat organs following intravascular administration of3H-labeled peptide

The organ distribution of radioactivity following intravascular bolus injection of³H-Lys-head growth activator in rats was studied. Two minutes after injection the renal level of radioactivity exceeded the blood level 7-fold; 80% of the total activity was bound with the blood cell membranes. An analysis of chemical derivatives of the labeled peptide in the plasma by means of reverse-phase high-performance liquid chromatography revealed the presence of several groups of radioactive metabolites with different hydrophilic properties. High-performance liquid chromatography of blood extracts obtained from samples taken 0.5, 1, 1.5, 2, 31, and 60 min after injection showed the transformation of initially hydrophobic head growth activator into more hydrophilic fragments. The³H-Lys-head growth activator-associated radioactivity could be reliably detected in the blood onl during the first two minutes after injection. The half-period of blood-to-organ distribution of³H-labeled head growth activator lasted less than 30 seconds. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 118, N ^o 11, pp. 466–469, November, 1994 Presented by E. I. Chazov, Member of the Russian Academy of Medical Sciences     

Staphylococcal catalase protects intracellularly survived bacteria by destroying H2O2 produced by the murine peritoneal macrophages

To determine the interrelationship between the hydrogen peroxide (H₂O₂) mediated killing and the potential role of bacterial catalase and SOD in the evasion of host defense, we examined three clinical isolates of Staphylococcus aureus and evaluated their intracellular survival mechanism within murine peritoneal macrophages. Fluorescent microscopy and bacterial colony-forming unit (cfu) count revealed that phagocytic capacity of murine peritoneal macrophages was highest after 2 h of in vitro infection with S. aureus. To understand whether catalase and SOD contributing in the intracellular survival, were of bacterial origin or not, 3 amino 1,2,4 triazole (ATZ) and Diethyldithiocarbamic acid (DDC) were used to inhibit specifically macrophage derived catalase and SOD respectively. Catalase activity from the whole staphylococcal cell in presence of ATZ suggested that the released catalase were of extracellular origin. Scanning electron microscopy revealed the degraded host cell membrane integrity during prolonged infection. Purified bacterial catalase from the intracellularly survived S. aureus recovered after 5 h of infection and its inhibition by ATZ in the zymography strengthened the scope of involvement of these anti-oxidants in the intracellular survival of S. aureus.     

Role of Bacterial Pathogens in Atopic Dermatitis

The skin of atopic dermatitis (AD) patients exhibits a striking susceptibility to colonization and infection with Staphylococcus aureus. This review summarizes our understanding about the role of S. aureus in AD. Indeed, S. aureus colonization is both a cause and a consequence of allergic skin inflammation. The mechanisms that allergic skin inflammation of AD promotes the increase of S. aureus colonization include skin barrier dysfunction, increased synthesis of the extracellular matrix adhesins for S. aureus, and defective innate immune responses due to decreased production of endogenous antimicrobial peptides. On the other hand, the exotoxins secreted by S. aureus are superantigens. Staphylococcal superantigens (SsAgs) may penetrate the skin barrier and contribute to the persistence and exacerbation of allergic skin inflammation in AD through the stimulation of massive T cells, the role of allergens, direct stimulation of antigen-presenting cells and keratinocytes, the expansion of skin-homing cutaneous lymphocyte-associated antigen-positive T cells, and the augmentation of allergen-induced skin inflammation. SsAgs also induce corticosteroid resistance. In therapeutic interventions, anti-inflammatory therapy alone is very effective in reducing S. aureus colonization on the skin, but antibiotic treatment alone is unable to improve the allergic skin inflammation of AD. Therefore, we recommend the combination therapy of anti-inflammatory drugs and antibiotics in the AD patients with secondary bacterial infection, exacerbated AD, or poorly controlled AD. However, when AD is well controlled by anti-inflammatory drugs alone, we do not recommend the antibiotic therapy.     

Lymphatic mast cell response and effect of compound 48/80 on popliteal lymph node reaction in rats following intracutaneous injection ofStaphylococcus aureus

To investigate the significance of mast cells in the popliteal lymph node during the development of an inflammatory response, rats were inoculated with 12×10⁷ colony-forming units ofStaphylococcus aureus in the hind foot pad. Numerical changes in mast cells were then measured in the corresponding popliteal lymph node. Six days after inoculation, despite the enlargement of the responding lymph node, a marked decrease in granulated mast cell number, relative to the contralateral node, was observed in the cortical and medullary compartments. Popliteal lymph nodes from rats treated with compound 48/80 and then inoculated withS. aureus showed a higher cortical and medullary hypertrophic response and a significant increase in degranulated/weakly basophilic mast cell number in the lymph node tissue. The findings suggest that (1)Staphylococcus aureus induces a reduction in granulated mast cell number in the cortical and medullary compartments of regional lymph nodes; (2) pretreatment with compound 48/80 appears to contribute to the lymphoid cell proliferation and the hypertrophic response of lymph nodes induced byS. aureus; and (3) granulated mast cells have a regulatory role on lymphoid cell proliferation.     

Some cytochemical peculiarities of the rat brain motor system after space flight

The results of cytochemical cytometry of rat brain suggest that a 9-day exposure of rats to microgravitation conditions lowers the activity of monoaminoxidase in the fibrous structures of layer V of the somatosensory cortex and in the head ofnucleus caudatus, as well as the activity of acetylcholine esterase in the bodies of neurons forming the head ofn. caudatus. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 3, pp. 288–290, March, 1995 Presented by the late O. S. Adrianov, Member of the Russian Academy of Medical Sciences