Antigenicity, expression, and molecular characterization of surface-located pullulanase of Streptococcus pneumoniae.

A putative pullulanase-encoding gene from Streptococcus pneumoniae was identified by screening a genomic expression library with human convalescent-phase serum. The 3,864-bp gene encoded a 143-kDa protein. Surface location and pullulanase activity of the protein, designated SpuA, was demonstrated.

Distribution of macrolide-resistance genes in Staphylococcus aureus blood-culture isolates from fifteen German university hospitals. M.A.R.S. Study Group. Multicentre Study on Antibiotic Resistance in Staphylococci.

The purpose of the study was to analyze the distribution of the macrolide-resistance genes in 134 erythromycin-resistant Staphylococcus aureus blood-culture isolates collected at 15 German university hospitals. The most prevalent resistance gene was ermC (68/134; 50.7%), followed by ermA (52/134; 38.

Interleukin-1 inhibits gamma interferon-induced bacteriostasis in human uroepithelial cells.

The most prominent gamma interferon (IFN-gamma)-induced antimicrobial effector mechanisms are the induction of nitric oxide (NO) synthase (NOS) and of indoleamine 2,3-dioxygenase (IDO) activity. We have recently found that human glioblastoma cells and human macrophages inhibit the growth of group B streptococci after stimulation with IFN-gamma. In this report, we show that in addition, human RT4 (uroepithelial) cells can inhibit the growth of enterococci.

The adherence-associated lipoprotein P100, encoded by an opp operon structure, functions as the oligopeptide-binding domain OppA of a putative oligopeptide transport system in Mycoplasma hominis.

Mycoplasma hominis, a cell-wall-less prokaryote, was shown to be cytoadherent by the participation of a 100-kDa membrane protein (P100). To identify the gene encoding P100, peptides of P100 were partially sequenced to enable the synthesis of P100-specific oligonucleotides suitable as probes for the detection of the P100 gene. With this strategy, we identified a genomic region of about 10.

Cyto-adherence studies of the adhesin P50 of Mycoplasma hominis.

Recombinant peptides of Mycoplasma hominis adhesin P50 were expressed in Escherichia coli to investigate which regions of the P50 molecule are responsible for cyto-adherence. The respective DNA fragments were obtained by PCR amplification of the p50 gene with the use of mutating oligonucleotides to change the TGA codons of mycoplasma to TGG codons, which are translated in E. coli as tryptophan.

Differential CD86/B7-2 expression and cytokine secretion induced by Toxoplasma gondii in macrophages from resistant or susceptible BALB H-2 congenic mice.

The influence of the intracellular parasite Toxoplasma gondii on macrophage expression of co-stimulatory molecules was studied. Unlike surface expression of CD80/B7-1, that of CD86/B7-2 is increased in mouse peritoneal macrophages 24 h following exposure to live toxoplasma in vitro. Most CD86 molecules are found on infected cells bearing a maximum parasite load.

Inducible anti-parasitic effector mechanisms in human uroepithelial cells: tryptophan degradation vs. NO production.

In murine cells the most important effector mechanism directed against the intracellular pathogen Toxoplasma gondii is the production of toxic nitrogen oxides. In contrast the induction of the tryptophan degrading enzyme indolamine 2,3-dioxygenase (IDO) has been described to be the most effective anti-parasitic mechanism in most human cells. In this report we analysed IDO induction and NO production in the human uroepithelial carcinoma cell line RT4.

The effect of reserpine, an inhibitor of multidrug efflux pumps, on the in-vitro activities of ciprofloxacin, sparfloxacin and moxifloxacin against clinical isolates of Staphylococcus aureus.

In Staphylococcus aureus, in addition to mutations in the grl and gyr gene loci, multidrug efflux pumps like NorA contribute to decreased fluoroquinolone susceptibility. Efflux pumps can be inhibited by the plant alkaloid reserpine, which, at 20 mg/L, reduced sparfloxacin, moxifloxacin and ciprofloxacin IC50s and MICs by up to four-fold in 11, 21 and 48 of the 102 unrelated clinical isolates tested, respectively. The effect was less pronounced with the hydrophobic drugs sparfloxacin and moxifloxacin than with the hydrophilic drug ciprofloxacin and was stable in all 25 clonally related isolates tested.

Reduction in cytokine release from human monocytes by modifications in cell wall structure of Staphylococcus aureus induced by subinhibitory concentrations of oxacillin.

Whole bacterial cells of Staphylococcus aureus as well as purified staphylococcal peptidoglycan (PG) have been demonstrated to stimulate human monocytes to release cytokines. Hypothesising that the phenomenon of changes induced by beta-lactam antibiotics in cell-wall composition may alter the immunological properties of the intact cell wall as well as of purified cell-wall components, this study assessed whether cytokine release by human monocytes is altered if cells from strains grown in the presence or absence of sub-minimal inhibitory concentrations of oxacillin are used as stimuli. Whole bacterial cells and isolated PG from these strains, grown in the presence of oxacillin, showed a significantly reduced stimulation of tumour necrosis factor-alpha, interleukin (IL)-1beta and IL-6 release by human monocytes in a concentration-dependent fashion.

Truncation as a novel form of variation of the p50 gene in Mycoplasma hominis.

A characteristic feature of the mycoplasmas is the presence of variable surface proteins which may play an important role in the adaptation of the cell-wall-less organisms to their host environments. In addition, this antigen variation may be an important pathogenic property of the organism. The ubiquity of the gene encoding P50, an adhesin of Mycoplasma hominis FBG, and its transcription were analysed in different isolates of M.

Cloning and expression of P60, a conserved surface-localized protein of Mycoplasma hominis, in Escherichia coli.

The clp60 gene encoding P60, a conserved lipoprotein of Mycoplasma hominis, was cloned and sequenced from both the type strain PG21 and the isolate FBG. Both open reading frames were identical in length, comprising 1746 nucleotides. The deduced amino acid sequences differed in 16 out of 582 amino acids.

Interferon-gamma-induced activation of indoleamine 2,3-dioxygenase in cord blood monocyte-derived macrophages inhibits the growth of group B streptococci.

Neonatal sepsis is most often caused by group B streptococci (GBS) and is a major cause of death in the neonatal period. The response of the immune system in the newborn child has received much attention and is thought to be deficient in a number of ways. The effector response of neonatal monocyte-derived macrophages (MDM) was investigated.

Characterization of grlA, grlB, gyrA, and gyrB mutations in 116 unrelated isolates of Staphylococcus aureus and effects of mutations on ciprofloxacin MIC.

One hundred sixteen unrelated clinical isolates of Staphylococcus aureus (70 ciprofloxacin resistant and 46 ciprofloxacin susceptible) from eight countries were studied for the presence of mutations in the grlA, grlB, gyrA, and gyrB gene loci. Two mutations within grlA (located at codons 80 and 84) and two mutations within gyrA (located at codons 84 and 88) were clearly associated with ciprofloxacin resistance, although other mutations detected within the four genes studied may also contribute to decreased susceptibility.

Development of a multiplex-PCR for direct detection of the genes for enterotoxin B and C, and toxic shock syndrome toxin-1 in Staphylococcus aureus isolates.

As well as conventional methods such as immunodiffusion, ELISA, or agglutination for the detection of toxin production in Staphylococcus aureus, amplification techniques like PCR allow a very sensitive and specific identification of the genes responsible for enterotoxin B and C, and TSST-1 production. These toxins might be a cause of the toxic shock syndrome (TSS). For that reason an easy and quick test system for determining the toxin production pattern of S.

Methicillin resistant Staphylococcus aureus strains in the greater Düsseldorf area.

Over a period of three years the incidence of methicillin resistant Staphylococcus aureus (MRSA) isolates in 11 hospitals in the greater Düsseldorf area was observed. From a total of 7,814 S. aureus isolates, 489 (6.

Enterotoxin and toxic shock syndrome toxin-1 production of methicillin resistant and methicillin sensitive Staphylococcus aureus strains.

In this study the production of enterotoxin A-D and toxic shock syndrome toxin-1 (TSST-1) of 181 methicillin resistant (MRSA) and 100 methicillin sensitive (MSSA) Staphylococcus aureus first isolates from different patients was investigated. All the MRSA- and MSSA isolates in the study were collected in a period between 1993 and 1995 from specimens sent from 11 different acute care hospitals in the greater Düsseldorf area. As far as possible the isolates were matched according to ward and hospital.

[Insertion possibility of 16S-23S space amplification and random amplified polymorphic DNA analysis for typing of methicillin-resistant Staphylococcus aureus strains in the context of nosocomial infections].

Within the scope of the present study n = 183 MRSA isolates from the extended area of Düsseldorf and n = 93 international MRSA strains from seven different countries were typed by pulsed-field gel electrophoresis and two PCR methods (RAPD and 16S-23S-spacer amplification). The isolates could be subdivided into 30 different types by PFGE, into 21 by means of RAPD and 18 by 16S-23S-spacer amplification. PFGE had the highest discriminatory potential, however, a combined use of the three typing methods allows a more detailed differentiation even of those isolates with identical PFGE pattern.

Cytokine responses induced by Toxoplasma gondii in astrocytes and microglial cells.

To investigate the role of astroglia in intracerebral immune response to Toxoplasma gondii, astrocytes cultured from mouse brain were inoculated with mouse-virulent or -avirulent toxoplasma strains. In comparison to microglia/ brain macrophages, astrocytes as host cells allowed stronger proliferation of avirulent parasites. Toxoplasma infection of astroglia was accompanied by release of interleukin- (IL)1 alpha, IL-6, and granulocyte/macrophage colony-stimulating factor (GM-CSF) activity, whereas alternative challenge by lipopolysaccharide (LPS) evoked no IL-1 response and significantly higher titers of IL-6 and GM-CSF.

Cellular immune reactions directed against Toxoplasma gondii with special emphasis on the central nervous system.

Toxoplasma gondii is an obligate intracellular parasite which, after primary infection of humans, is maintained in a dormant state by the host cellular immune system. In the event of an acquired immunosuppression, those parasites surviving as dormant cysts in the host may undergo a change in status, proliferate and cause a life-threatening toxoplasmic encephalitis. Over the last decade much knowledge has accumulated concerning the immune response against T.

Host cells of Toxoplasma gondii encystation in infected primary culture from mouse brain.

In order to identify brain cell types that serve as host cells of Toxoplasma gondii encystation primary cultures from murine brain were infected and stained for neural and parasite stage-specific markers. In mixed culture inoculated with T. gondii tachyzoites, MAP2+ neurons, GFAP+ astrocytes, F4/80+ microglia, and O1+ oligodendrocytes proved to be infected as detected by parallel labeling of SAG1.

Biovar-specific epitopes of the urease enzyme of Ureaplasma urealyticum.

The importance of Ureaplasma urealyticum as a pathogen in premature neonates and patients with a profound defect in humoral immunity has, over the last few years, become well recognised. U. urealyticum is unique amongst the Mycoplasmataceae for its use of urea metabolism as an essential source of energy.

Repetitive elements of the Mycoplasma hominis adhesin p50 can be differentiated by monoclonal antibodies.

The gene encoding p50, an adhesin of Mycoplasma hominis, was identified, cloned, and sequenced. Comparison of the derived amino acid sequence with the N-terminal amino acids sequenced by the Edman reaction of the native protein revealed that p50 is expressed as a 467-amino-acid precursor. Posttranslational modification leads to a 441-amino-acid lipoprotein with an extended, predominantly helical structure and a leucine zipper.