Prevalence of resistance to MLS antibiotics in 20 European university hospitals participating in the European SENTRY surveillance programme. Sentry Participants Group.

Macrolide, lincosamide and streptogramin (MLS) antibiotics are chemically distinct inhibitors of bacterial protein synthesis. Resistance to MLS antibiotics may be constitutive or inducible. The purpose of this study is to update our understanding of the prevalence of different forms of MLS resistance in Europe.

Early gene expression of NK cell-activating chemokines in mice resistant to Leishmania major.

Susceptibility of mice to Leishmania major is associated with an insufficient NK cell-mediated innate immune response. We analyzed the expression of NK cell-activating chemokines in vivo during the first days of infection in resistant and susceptible mice. The mRNA expression of gamma interferon-inducible protein 10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), and lymphotactin was upregulated 1 day after infection in the draining lymph nodes of resistant C57BL/6 mice but not in those of susceptible BALB/c mice.

Suppression of TNF by V antigen of Yersinia spp. involves activated T cells.

The 39-kDa V antigen (Vag) of pathogenic Yersinia species has been described to be a potent suppressor of TNF production. The underlying cellular and molecular mechanisms, however, are completely undefined. Here we show that Vag does not act directly on macrophages, the primary source of TNF, but rather requires help of activated T cells for TNF suppression.

Analysis of the Yersinia enterocolitica 0:8 V antigen for cross protectivity.

The plasmid encoded V antigen (Vag) of pathogenic Yersinia spp. is a major virulence factor as well as a protective immunogen. Recently, two main types of Vag, represented by either Yersinia enterocolitica 0:8 or Yersinia pseudotuberculosis, have been identified and it has been suggested, that antibodies generated against one type are unable to protect against Yersinia spp.

Class I integrons in Gram-negative isolates from different European hospitals and association with decreased susceptibility to multiple antibiotic compounds.

Class I integrons are associated with carriage of genes encoding resistance to antibiotics. Expression of inserted resistance genes within these structures can be poor and, as such, the clinical relevance in terms of the effect of integron carriage on susceptibility has not been investigated. Of 163 unrelated Gram-negative isolates randomly selected from the intensive care and surgical units of 14 different hospitals in nine European countries, 43.

Many class I integrons comprise distinct stable structures occurring in different species of Enterobacteriaceae isolated from widespread geographic regions in Europe.

Three sizes of inserted regions of DNA (800, 1,000, and 1,500 bp) were shown to be common among class I integrons in unrelated clinical isolates of Enterobacteriaceae from different European hospitals. Sequencing showed that 800-bp inserted regions comprised identical sequences including aacA4, that 1,000-bp inserted regions included aadA, and that 1,500-bp inserted regions included dfrI and aadA1, irrespective of host species and geographic origin. In addition promoter sequences were mostly identical for each size class.

Comparative activities of clinafloxacin, grepafloxacin, levofloxacin, moxifloxacin, ofloxacin, sparfloxacin, and trovafloxacin and nonquinolones linozelid, quinupristin-dalfopristin, gentamicin, and vancomycin against clinical isolates of ciprofloxacin-resistant and -susceptible Staphylococcus aureus strains.

The activities of eight fluoroquinolones and linezolid, quinupristin-dalfopristin (Synercid), gentamicin, and vancomycin were tested against 96 ciprofloxacin-susceptible and 205 ciprofloxacin-resistant Staphylococcus aureus strains. Overall, clinafloxacin, followed by moxifloxacin and trovafloxacin, was the most active quinolone tested. For all isolates, linezolid and quinupristin-dalfopristin showed activities that were at least comparable to vancomycin, with no cross-resistance to any other test compound.

Presence and significance of human parvovirus B19 DNA in synovial membranes and bone marrow from patients with arthritis of unknown origin.

Acute rheumatologic symptoms are frequently associated with human parvovirus B19 (B19) infections. A nested PCR (nPCR) assay was used to test for the presence of parvovirus B19 DNA in synovial fluid and/or synovial membrane specimens obtained from a total of 90 patients with arthritis of unknown origin. Whereas only one out of 73 synovial fluid samples were found positive, 15 (16.

A nested-PCR assay for the simultaneous amplification of HSV-1, HSV-2, and HCMV genomes in patients with presumed herpetic CNS infections.

To facilitate early diagnosis of herpes virus infection of the central nervous system (CNS), a nested polymerase chain reaction (nPCR) assay was developed to test simultaneously for the presence of HSV-1, HSV-2, and HCMV DNA in the cerebrospinal fluid (CSF) of patients with herpetic CNS disease suspected on clinical grounds. The virus type-specific PCR products were differentiated either by agarose gel electrophoresis or by DNA enzyme immunoassay. Using titrated viral stocks as standards, a sensitivity of at least 0.

Evidence for persistence of human parvovirus B19 DNA in bone marrow.

A nested polymerase chain reaction assay (nPCR) was used to investigate the potential of human parvovirus B19 DNA to persist in blood or bone marrow samples obtained either from blood donors or cadaveric bone donors or from patients presenting with clinical signs of parvovirus B19 infection. The presence of parvovirus B19 specific antibody in blood was tested by enzyme immunoassay (EIA). B19 virus genome was not detected in any blood sample of 115 blood donors, of whom 92 (80%) had anti-B19 IgG antibody only as an indication of past infection.

Effect of antiviral treatment on the shedding of HIV-1 in semen.

Objective: The potential role of antiretroviral treatment on the infectiousness of HIV-1-infected men was examined by studying the effect of antiviral treatment on the shedding of HIV-1 in semen.

Methods: Forty-four patients enrolled in various treatment protocols were asked to donate a semen sample before they began a new antiviral treatment and at a follow-up visit after 6 to 15 weeks of treatment. Since most patients were on blinded protocols, patients were stratified by response of blood viral load.

Quantification of HIV in semen: correlation with antiviral treatment and immune status.

Objective: This study examined the concentration of HIV in semen and the effects of biological factors on HIV excretion.

Methods: Semen samples from 101 men at different stages of the disease were evaluated by quantitative HIV culture and HIV RNA detection. Blood plasma samples were available from 56 patients.

In vivo blocking of L-selectin rescues BALB/c mice from fatal Leishmania major infection.

Susceptibility and resistance to experimental Leishmania major (L. major) infection in mice are associated with a Th2- or Th1-type response, respectively. We have previously shown that immunological events occurring within the first 24 h after infection in the lymph node (LN) draining the site of parasite challenge are critical for the development of either type of T-cell responses.

Identification of active-site residues in protease 3C of hepatitis A virus by site-directed mutagenesis.

Picornavirus 3C proteases (3Cpro) are cysteine proteases related by amino acid sequence to trypsin-like serine proteases. Comparisons of 3Cpro of hepatitis A virus (HAV) to those of other picornaviruses have resulted in prediction of active-site residues: histidine at position 44 (H44), aspartic acid (D98), and cysteine (C172). To test whether these residues are key members of a putative catalytic triad, oligonucleotide-directed mutagenesis was targeted to 3Cpro in the context of natural polypeptide precursor P3.

Control of Leishmania major infection in BALB/c mice by inhibition of early lymphocyte entry into peripheral lymph nodes.

A single i.p. injection with the anti-CD62L (anti-L-selectin) mAb Mel-14 before parasite challenge protected BALB/c mice from the otherwise lethal infection with Leishmania major.

Suitability and clinical application of a multiplex nested PCR assay for the diagnosis of herpes simplex virus infections.

A novel multiplex nested polymerase chain reaction (PCR) assay was designed and evaluated for routine diagnosis of herpes simplex virus (HSV) infections in patients with either putative HSV infection of the central nervous system or suspected HSV keratitis. Single-tube amplification of HSV type 1 (HSV-1) or type 2 (HSV-2) DNA extracted from cerebrospinal fluid (CSF) or from keratectomy specimens was followed by differentiation of the virus type-specific PCR products either by agarose gel analysis or by DNA enzyme immunoassay. Among 417 CSF specimens obtained from 395 consecutive patients with clinically suspected HSV infection, 11 (2.

Identification of hepatitis A virus non-structural protein 2B and its release by the major virus protease 3C.

The RNA genome of hepatitis A virus (HAV) encodes a giant polyprotein that is putatively cleaved proteolytically into four structural and seven non-structural proteins. So far, most of the proposed non-structural proteins and their respective cleavage sites have not been identified. A vaccinia virus recombinant (vRGORF) containing the complete HAV ORF under the control of the bacteriophage T7 promoter was used to express HAV in recombinant animal cells (BT7-H) that constitutively expressed T7 DNA-dependent RNA polymerase.

Bone and joint infections caused by gram-negative bacteria.

Infections of the bones and joints caused by gram-negative bacteria from the family Enterobacteriaceae account for 10%-15%. This family usually cause opportunistic infections, due to a low virulence factor, host and environmental factors. Gram-negative bacteria cause osteomyelitis, infectious arthritis and Reiter's syndrome.

Lack of inducible nitric oxide synthase activity in T cell clones and T lymphocytes from naive and Leishmania major-infected mice.

Nitric oxide (NO) generated by the inducible isoform of nitric oxide synthase (iNOS) is implicated in a number of immunological processes including killing of intracellular parasites, suppression of T cell proliferation, production of cytokines and destruction of tissue in autoimmune diseases. Considering that cytokine-activated mouse macrophages, fibroblasts and endothelial cells are potent producers of NO, we investigated whether T cells, as central participants in immune responses, can also be activated for the release of NO. Neither thymocytes nor type 1 or type 2 T helper cell clones generated significant amounts of nitrite (the stable end product of NO in culture supernatants) when stimulated by T cell mitogens, cytokines or antigen in the presence of irradiated antigen-presenting cells.

Leishmania major infection: the overture.

Local infection of mice with Leishmania major results in either healing or death depending on the preferential action of Th1 or Th2 T helper cells, respectively. Although the parasite-induced T-cell responses and their consequences for the disease are well understood, relatively little is known about the initial events that kindle the adaptive immune response. Werner Salbach and Tamás Laskay here discuss how differences in parasites spreading from the site of infection to different immune organs during the first 10-24 hours and, in consequence, the 'where and when' of the first encounter of Leishmania with the cells of the immune system may well be the starting point for the development of resistance or susceptibility.

Early parasite containment is decisive for resistance to Leishmania major infection.

We investigated the early spread of Leishmania major in various mouse strains. In BALB/c mice, which are extremely vulnerable to L. major infection, the parasites disseminated within 10-24 h from the site of subcutaneous footpad infection in to the popliteal lymph node, spleen, lung, liver and bone marrow.

Association between human parvovirus B19 infection and arthritis.

Objective: To gain information concerning the association between parvovirus B19 infection and arthritis.

Methods: Blood or synovial fluid, or both, from a total of 77 adult patients with various arthropathies (rheumatoid arthritis 13; mechanical arthropathies 11; crystal induced arthritis 13; idiopathic mono/oligoarthritis 25; suspicion of viral arthritis 15) were tested for the presence of the viral genome and anti-B19 antibodies. B19 DNA in blood and synovial fluid was investigated by nested polymerase chain reaction, and anti-B19 IgM and IgG antibodies were detected in blood by enzyme immunoassay.

2,4-Diamino-6-hydroxypyrimidine, an inhibitor of tetrahydrobiopterin synthesis, downregulates the expression of iNOS protein and mRNA in primary murine macrophages.

2,4-diamino-6-hydroxy-pyrimidine (DAHP), an inhibitor of GTP cyclohydrolase I, blocks the synthesis of tetrahydrobiopterin (BH4), which is a known cofactor of inducible nitric oxide synthase (iNOS). Previously, DAHP was shown to suppress the production of nitric oxide by cytokine-activated fibroblasts, smooth muscle cells or endothelial cells which could be attributed to its function as a cofactor antagonist. Here, we demonstrate that in interferon-gamma-activated murine peritoneal macrophages DAHP suppresses the expression of iNOS mRNA and protein in a BH4-independent manner and, thus, acts by a novel mechanism.