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Biomedical subjects

R Marre

Publications and source records attributed to R Marre.

At least 91 records · Page 5Linked to original sources
PubMed1992

Is Escherichia coli invading tubuloepithelial cells?

The adhesion of Escherichia coli to host epithelium cells is the very first step of urinary tract infections followed by the internalization of the bacteria into these cells. These steps are influenced by several surface antigens or products of the pathogen, e.g. fimbriae or adhesins, K antigen, and hemolysin. The bacterial adherence and the internalization of several isogenic E. coli O18 strains differing in the expression of K5 antigen, hemolysin, and type of fimbriae were measured by using a permanent line of porcine tubuloepithelial cells (LLC-PK1). Strains with K5 antigen were reduced in their adherence and internalizability as compared to the K-negative strains. The expression of hemolysin by these strains lead to an increase of adherence and internalization. The internalization of bacteria is influenced mainly by their adherence to the epithelial cells. Thus, the engorgement of attached bacteria is rather a kind of endocytosis than an invasion of bacteria.

Animals↗
PubMed1992

Purification and characterisation of elastase from Staphylococcus epidermidis.

An elastase of Staphylococcus epidermidis was purified by ion exchange chromatography on CM-Sepharose and characterised. Its M(r) is c. 21 kDa, its optimal temperature for activity is 42 degrees C and the pH optimum is 6.8. The enzyme is activated by cysteine and other SH-donators and inhibited by L-trans-epoxy-succinylleucylamido-(4-guanidino)butane (E64), an inhibitor of cysteine proteases, but not by 3,4-dichloroisocoumarin (3,4-DCI), an inhibitor of serine proteases. This finding suggests that the elastase of S. epidermidis is a cysteine protease. Because S. epidermidis elastase degrades human sIgA, IgM, serum albumin, fibrinogen, and fibronectin, this enzyme may be regarded as a virulence factor.

Chromatography, Ion Exchange↗
PubMed1992

Aggregation substance of Enterococcus faecalis mediates adhesion to cultured renal tubular cells.

The sex pheromone system of Enterococcus faecalis is a unique, highly efficient plasmid collection mechanism for this species. A crucial role in this system is played by an adhesin called aggregation substance which enables the cell-cell contact between donor and recipient strains. The existence of the amino acid motif Arg-Gly-Asp-Ser in the adhesin prompted us to look for a possible binding of E. faecalis cells expressing aggregation substance to eucaryotic cells. We were able to show that the adhesin mediated binding to cultured renal tubular cells (porcine cell line LLC-PK1) via light microscopic, electron microscopic, and enzyme-linked immunosorbent assay-based studies. Synthesis of the adhesin was induced by some component(s) of serum. These data are interpreted to mean that aggregation substance is an adhesin mediating not only cell-cell contact between different E. faecalis strains but also binding of E. faecalis to eucaryotic cells, and therefore it might contribute to virulence.

Amino Acid Sequence↗
PubMed1992

Identification and characterization of a surface-associated protein (Ssp) of Staphylococcus saprophyticus.

A 95-kDa protein was isolated from Staphylococcus saprophyticus 7108 grown on dialysis membranes placed on the surface of brain heart infusion agar. Strain CCM883 did not produce this protein. Ultrathin sections revealed the presence of very thin, tuftlike, 50- to 75-nm-long structures on the surface of strain 7108, whereas strain CCM883 was comparably smooth. The surface material could be removed by digestion with proteinase K, suggesting that the surface structures contain protein. High-resolution scanning electron microscopy showed a thick layer of surface material on strain 7108, whereas strain CCM883 appeared smooth. The 95-kDa protein was purified by Sephacryl S-300 chromatography, and an antiserum was raised in rabbits. This antiserum was used in immunogold labeling experiments, which showed that the protein is associated with the surface structures. Our experiments thus demonstrate the presence of a fibrillar protein on the surface of S. saprophyticus (Ssp for S. saprophyticus surface-associated protein).

Animals↗
PubMed1992

[Myeloperoxidase, lactoferrin and elastase in bronchoalveolar lavage and plasma in pneumonia].

Neutrophilic granulocytes in the lower respiratory tract are of decisive importance for the elimination of pathogenic germs in bacterial pneumonia. On the other hand, the liberation of phagocyte products (e.g. elastase) can result in tissue damage in the parenchyma of the lungs. For this reason, we determined in patients suffering from acute pneumonia (n = 21), in patients with acute pneumonia associated with immunosuppression (n = 12), in patients who had overcome their pneumonia (n = 9) and in controls (n = 17) in bronchoalveolar lavage (BALF) and in plasma, the concentration of the locally produced granulocyte products myeloperoxidase (MPO), lactoferrin (LF) and elastase-alpha 1 proteinase complex (ELA) as well as of the alpha 1 proteinase inhibitor (alpha 1 Pi) and alpha 2 proteinase inhibitor (alpha 2 Pi) via chemoluminescence immunoassay, and compared the same with the differential cell count in the BALF. The protein concentrations were referred to the albumin concentration (Alb) for standardisation. This concentration did not differ significantly between the various patients and control groups. The BALF concentration of ELA in the group with pneumonia (median: 86.3 micrograms/l or 8.5 micrograms/mg Alb) was about eight times higher than in the group of patients suffering from pneumonia with immunosuppression (median: 16 micrograms/l or 1.0 micrograms/l Alb, p less than 0.001) or in whom the pneumonia was no longer present (17.6 micrograms/l or 0.5 micrograms/mg), and approximately 40 times higher than in the control group (3 micrograms/l or 0.2 micrograms/mg, respectively). Similar results were obtained for LF (61 micrograms/mg Alb vs. 11.3; 16.8 and 5.9 micrograms/mg; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Adhesion of Staphylococcus saprophyticus to renal tubular epithelial cells is mediated by an N-acetyl-galactosamine-specific structure.

S. saprophyticus CCM883 and 9325 were found to adhere to the tubular cell line LLC-PK1. An ELISA technique was used to determine adherence of bacteria and inhibition of adherence by various carbohydrates. Only N-acetyl-galactosamine was found to significantly inhibit adhesion (p less than 0.001), which suggests that the surface component mediating adhesion recognizes structures on the target cell that contain this carbohydrate.

Acetylgalactosamine↗
PubMed1991

Experimental studies on the nephrotoxicity of amphotericin B in rats.

The renal effects of amphotericin B alone and in combination with cyclosporin A, tobramycin, fosfomycin, D-glucaro-1,5-lactam and verapamil were studied in rats. The parameters for nephrotoxicity were urinary loss of tubular cells and malate dehydrogenase, as well as creatinine clearance. Repeated intraperitoneal injections of amphotericin B led to an increase of urinary tubular cell elimination and malate-dehydrogenase. After co-administration of amphotericin B and cyclosporin A, the urinary loss of tubular cells increased and creatinine clearance was reduced. A combination of amphotericin B and tobramycin reduced tubular cell elimination but the creatinine clearance improved. When verapamil was combined with amphotericin B, endogenous creatinine clearance increased, though the loss of tubular cells was elevated. Furthermore, fosfomycin reduced the loss of tubular cells and improved renal functional parameters in combination with amphotericin B. In addition, D-glucaro-1,5-lactam was found to reduce the urinary loss of tubular cells induced by amphotericin B.

Amphotericin B↗
PubMed1991

Temperature-dependent expression of flagella in Legionella.

Legionella pneumophila, the causative agent of Legionnaires' disease, was analysed by electron microscopy for production of surface structures. Crystalline surface (S-) layers and fimbriae were not detected, but monotrichous flagellation was seen. Polyclonal antibodies specific for the 47 kDa flagellin subunit of L. pneumophila Philadelphia I were used in Western blots to confirm the presence of flagella subunits in various L. pneumophila strains tested, but the antiserum also reacted with flagellin subunits of L. micdadei, L. hackelia [serogroup (SG) 1 and SG2] and L. longbeachae (SG2). Flagellation of Legionellae was shown to be temperature regulated. When the growth temperature of virulent and avirulent of strain L. pneumophila Philadelphia I was shifted from 30 degrees C to either 37 or 41 degrees C, a decrease in the percentage of flagellated bacteria within the population was observed.

Bacterial Outer Membrane Proteins↗
PubMed1991

Cloning, genetic analysis, and nucleotide sequence of a determinant coding for a 19-kilodalton peptidoglycan-associated protein (Ppl) of Legionella pneumophila.

A genomic library of Legionella pneumophila, the causative agent of Legionnaires disease in humans, was constructed in Escherichia coli K-12, and the recombinant clones were screened by immuno-colony blots with an antiserum raised against heat-killed L. pneumophila. Twenty-three clones coding for a Legionella-specific protein of 19 kDa were isolated. The 19-kDa protein, which represents an outer membrane protein, was found to be associated with the peptidoglycan layer both in L. pneumophila and in the recombinant E. coli clones. This was shown by electrophoresis and Western immunoblot analysis of bacterial cell membrane fractions with a monospecific polyclonal 19-kDa protein-specific antiserum. The protein was termed peptidoglycan-associated protein of L. pneumophila (Ppl). The corresponding genetic determinant, ppl, was subcloned on a 1.8-kb ClaI fragment. DNA sequence studies revealed that two open reading frames, pplA and pplB, coding for putative proteins of 18.9 and 16.8 kDa, respectively, were located on the ClaI fragment. Exonuclease III digestion studies confirmed that pplA is the gene coding for the peptidoglycan-associated 19-kDa protein of L. pneumophila. The amino acid sequence of PplA exhibits a high degree of homology to the sequences of the Pal lipoproteins of E. coli K-12 and Haemophilus influenzae.

Amino Acid Sequence↗
PubMed1991

Pulsed field electrophoresis of genomic restriction fragments for the detection of nosocomial Legionella pneumophila in hospital water supplies.

Ten Legionella pneumophila strains isolated from different sources were analyzed according to their restriction fragment patterns obtained by cleavage of genomic DNA with NotI and SfiI and separation by pulsed field electrophoresis. Three L. pneumophila isolates from a nosocomial outbreak in Lübeck (Germany) and three other L. pneumophila strains independently isolated from a water tap located in the care unit where the patients were hospitalized exhibited identical restriction fragment profiles. Therefore, we concluded that these environmental specimens were the source of the Legionnaires disease. Another two isolates from patients and two strains from the environment, all unrelated to the outbreak described, showed different cleavage patterns.

Adult↗
PubMed1990

[Bronchoscopic diagnosis of pneumonia with quantitative microbial count determination].

Micro-organism counts of bronchoalveolar lavage (BAL) and microbrush swabs were obtained from 40 immunocompetent (group A) and 23 immunosuppressed (group B) patients with nosocomial pneumonia, and a control group consisting of 40 patients with noninfectious pulmonary infiltrates. The sensitivity of BAL was high: 77.5% for group A and 85% for group B, while microbrush swabs gave many false-negative results. Microorganism counts were at or above 10(5) cfu/ml in 32 of 44 examinations (bacterial or mycotic pneumonia), but in only one case of the control group. Lower counts were obtained with localized infection and microorganisms difficult to culture (Aspergilla and Legionella). Granulocytosis in the lavage fluid was demonstrated in 38 of 41 patients with bacterial pneumonia and thus proved useful in the differential diagnosis. In 16 of 40 immunocompetent and 13 of 23 immunosuppressed patients with pneumonia the results were therapeutically of importance. Thus, invasive diagnosis is indicated especially in complicated or treatment-resistant nosocomial infections.

Adult↗
PubMed1990

Beta-lactamase types and beta-lactam resistance of Escherichia coli strains with chromosomally mediated ampicillin resistance.

On the basis of isoelectric focusing six beta-lactamase types could be distinguished in ampicillin-resistant and ampicillin-sensitive strains of Escherichia coli. More than 90% of the ampicillin-resistant strains produced the same beta-lactamase type. The serotypes found in a group of ampicillin-resistant urinary tract infection strains did not represent the distribution usually found in urinary tract isolates. Chromosomal ampicillin resistance was always associated with high cephalothin MIC values and increased resistance to other beta-lactam antibiotics of the cephalosporin group.

Ampicillin Resistance↗
PubMed1990

Genome analysis of Legionella ssp. by orthogonal field alternation gel electrophoresis (OFAGE).

Various Legionella isolates from different sources and origins were analysed by orthogonal field alternation gel electrophoresis of NotI cleaved genomic DNA. The genome of L. pneumophila Philadelphia I, the original isolate of the epidemics in 1976, exhibits only five NotI fragments. Two virulent derivatives, derived from L. pneumophila Philadelphia I, which were obtained by prolonged passage on artificial culture media, did not differ from their isogenic virulent strain according the NotI fragment pattern. By summing the lengths of the NotI fragments, the genome size of L. pneumophila Philadelphia I was calculated as approximately 3.9 Mb. Environmental L. pneumophila strains exhibited different NotI patterns, as did Legionella strains not belonging to the species pneumophila. The usefulness of DNA long range mapping of Legionella ssp. with NotI for epidemiology and evaluation of their evolutionary relationships is discussed.

Biological Evolution↗
PubMed1990

Deletions of chromosomal regions coding for fimbriae and hemolysins occur in vitro and in vivo in various extraintestinal Escherichia coli isolates.

Fimbrial adhesins and hemolysins contribute to pathogenicity of extraintestinal Escherichia coli isolates causing urinary tract infections (UTI), sepsis and new born meningitis (NBM). Using gene cloning techniques and pulse field electrophoresis in combination with Southern hybridizations it was demonstrated that the genetic determinants coding for P and 'P-related' fimbrial adhesins and hemolysins are closely linked on the chromosomes of different pathogenic E. coli wild-type isolates. For two UTI strains, 536 (O6:K15) and J96 (O4:K6), a co-deletion of the linked gene clusters coding for hemolysin and fimbriae was observed. The deleted DNA regions which also comprise flanking DNA sequences were termed 'pathogenicity DNA islands'. Such 'pathogenicity DNA islands' were also detected in the genome of O18:K1 isolates of OMP type 6 but were absent on the chromosomes of O18:K1 strains of OMP type 9. A mutant strain, 536-22 was selected from rat kidneys after intraurethral infection of animals with the wild-type parental strain 536. This particular isolate also shows deletions of 'pathogenicity islands' leading to a non-pathogenic phenotype. It is therefore concluded that excisions of 'pathogenicity islands' from chromosomes of pathogenic E. coli strains are not restricted to the laboratory but also occur in vivo. The generation of deletions may represent a general mechanism of bacterial virulence modulation.

Adhesins, Escherichia coli↗
PubMed1990

Experimental studies on nephrotoxicity and pharmacokinetics of LY 146032 (daptomycin) in rats.

The nephrotoxicity and pharmacokinetics of LY 146032 (daptomycin) were studied in an experimental rat model. Nephrotoxicity was assessed by measuring urinary loss of tubular cells and malate dehydrogenase. LY 146032 (10-250 mg/kg daily iv) led to a dose-dependent and reversible increase of cell elimination. The tubulo-toxic threshold dose is stated to be 10 mg/kg daily. Nephrotoxicity induced by LY 146032 can be reduced by coadministration of fosfomycin or D-glucaro-1.5-lactam, and enhanced by combination with tobramycin. LY 146032 accumulated in renal tissue during repeated administration. Electron microscopy revealed histopathological changes in the kidneys. Therefore the nephrotoxic potential of LY 146032 should be taken into consideration in clinical trials.

Animals↗
PubMed1990

Genetically engineered S and F1C fimbriae differ in their contribution to adherence of Escherichia coli to cultured renal tubular cells.

Escherichia coli K-12 strains producing S-fimbrial adhesins, F1C fimbriae, and mutagenized fimbriae were tested in a binding assay with a renal tubular cell line. S-fimbrial adhesins and F1C fimbriae mediated binding to tubular cells. The SfaA, SfaG, and SfaS subunits of S fimbriae contributed to attachment. Site-specific mutations in the sfaS gene reduced binding. The inhibition profile of F1C fimbriae resembled that of S fimbriae.

Adhesins, Escherichia coli↗
PubMed1990

[Microbiological diagnosis of lower respiratory tract infections].

Successful microbiological diagnosis of lower respiratory tract infections demands a close cooperation between clinician and clinical microbiologist. Because of the broad spectrum of possible respiratory pathogens precise requests are necessary for adequate laboratory procedures. The high rate of potential pathogens requires quantitative microbiological and cytological data in order to differentiate between colonisation and infection. Pathophysiological reactions on microbial colonisation of the bronchial tree may contribute to acute exacerbations of a chronic bronchitis. The precise role of microbial nocuous agents, however, remains to be clarified.

Bronchi↗