51
|
Hooper DC, Scott GS, Zborek A, Mikheeva T, Kean RB, Koprowski H, Spitsin SV. Uric acid, a peroxynitrite scavenger, inhibits CNS inflammation, blood-CNS barrier permeability changes, and tissue damage in a mouse model of multiple sclerosis. FASEB J 2000; 14:691-8. [PMID: 10744626 DOI: 10.1096/fasebj.14.5.691] [Citation(s) in RCA: 275] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Peroxynitrite (ONOO(-)), a toxic product of the free radicals nitric oxide and superoxide, has been implicated in the pathogenesis of CNS inflammatory diseases, including multiple sclerosis and its animal correlate experimental autoimmune encephalomyelitis (EAE). In this study we have assessed the mode of action of uric acid (UA), a purine metabolite and ONOO(-) scavenger, in the treatment of EAE. We show that if administered to mice before the onset of clinical EAE, UA interferes with the invasion of inflammatory cells into the CNS and prevents development of the disease. In mice with active EAE, exogenously administered UA penetrates the already compromised blood-CNS barrier, blocks ONOO(-)-mediated tyrosine nitration and apoptotic cell death in areas of inflammation in spinal cord tissues and promotes recovery of the animals. Moreover, UA treatment suppresses the enhanced blood-CNS barrier permeability characteristic of EAE. We postulate that UA acts at two levels in EAE: 1) by protecting the integrity of the blood-CNS barrier from ONOO(-)-induced permeability changes such that cell invasion and the resulting pathology is minimized; and 2) through a compromised blood-CNS barrier, by scavenging the ONOO(-) directly responsible for CNS tissue damage and death.
Collapse
Affiliation(s)
- D C Hooper
- Department of Microbiology and Immunology, Kimmel Cancer Institute, and the Biotechnology Foundation Laboratories, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| | | | | | | | | | | | | |
Collapse
|
52
|
Champion JM, Kean RB, Rupprecht CE, Notkins AL, Koprowski H, Dietzschold B, Hooper DC. The development of monoclonal human rabies virus-neutralizing antibodies as a substitute for pooled human immune globulin in the prophylactic treatment of rabies virus exposure. J Immunol Methods 2000; 235:81-90. [PMID: 10675760 DOI: 10.1016/s0022-1759(99)00223-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To provide a more defined and safer replacement for the human rabies immune globulin (HRIG) from pooled serum which is currently used for treatment of exposure to rabies virus we have developed a series of human rabies virus-specific monoclonal antibodies. Mouse-human heterohybrid myeloma cells producing rabies virus-specific human monoclonal antibodies were prepared using B cells obtained from volunteers recently-immunized with a commercial rabies virus vaccine (HDCV). Cell lines producing antibody which neutralized the Evelyn-Rokitnicki-Abelseth (ERA) rabies virus strain in vitro were cloned and the resulting monoclonal antibodies characterized for isotype, specificity against a variety of rabies virus isolates, and neutralization capacity. The ability of the monoclonal antibodies to neutralize a variety of rabies virus strains in vitro correlated with their binding specificity for these viruses in an enzyme-linked immunoadsorbant assay (ELISA). A number of these antibodies have proven suitable for the formulation of a prophylactic human monoclonal antibody-based reagent which would provide significant advantages to the HRIG in having defined, reproducible specificity, lessened possibility of contamination with viral pathogens, and consistent availability.
Collapse
Affiliation(s)
- J M Champion
- Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, Rm. 454 JAH, 1020 Locust St., Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | | | |
Collapse
|
53
|
Affiliation(s)
- D C Hooper
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114-2696, USA.
| |
Collapse
|
54
|
Fournier B, Aras R, Hooper DC. Expression of the multidrug resistance transporter NorA from Staphylococcus aureus is modified by a two-component regulatory system. J Bacteriol 2000; 182:664-71. [PMID: 10633099 PMCID: PMC94328 DOI: 10.1128/jb.182.3.664-671.2000] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To dissect genetically the regulation of NorA, a multidrug transporter of Staphylococcus aureus, we analyzed the differential expression of the norA promoter using a transcriptional fusion with a beta-lactamase reporter gene. Expression studies with an arlS mutant revealed that the norA promoter is ArlS dependent. The arlR-arlS locus was shown to code for a two-component regulatory system. The protein ArlR has strong similarity to response regulators, and ArlS has strong similarity to protein histidine kinases. We have also analyzed the 350-bp region upstream of the Shine-Dalgarno sequence of norA by gel mobility shift experiments. It was shown that only the 115-bp region upstream of the promoter was necessary for multiple binding of an 18-kDa protein. From transcriptional fusions, we have localized four different putative boxes of 6 bp, which appear to play a role in the binding of the 18-kDa protein and in the up-regulation of norA expression in the presence of the arlS mutation. Furthermore, the gel mobility shift of the 18-kDa protein was modified in the presence of the arlS mutation, and the arlS mutation altered the growth-phase regulation of NorA. These results indicate that expression of norA is modified by a two-component regulatory system.
Collapse
Affiliation(s)
- B Fournier
- Infectious Disease Division and Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696, USA
| | | | | |
Collapse
|
55
|
Dietzschold B, Morimoto K, Hooper DC, Smith JS, Rupprecht CE, Koprowski H. Genotypic and phenotypic diversity of rabies virus variants involved in human rabies: implications for postexposure prophylaxis. J Hum Virol 2000; 3:50-7. [PMID: 10774807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
OBJECTIVES Rabies virus variants associated with silver-haired bats (SHBRV) are responsible for most recent human rabies cases in the United States, which are not associated with a history of exposure. We compared their genotype and phenotype with those of dog rabies virus (DRV) variants, the classic cause of rabies in humans, to determine whether differences in these strains might have ramifications for therapeutic intervention, particularly vaccination. METHODS Eleven silver-haired bat and 8 dog rabies virus isolates were characterized by sequencing the glycoprotein gene, by assessing their ability to replicate in neuronal versus nonneuronal cultures at optimal and suboptimal temperatures, by assessing their pathogenicity in mice, and by determining the resistance of these viruses to therapeutic immunization with commercial vaccines. RESULTS SHBRV isolates were less genetically diverse, less neuronal cell specific, more temperature sensitive, but as pathogenic, on average, as DRV isolates. Immune protection was equivalent for SHBRV and DRV strains of similar pathogenicity. CONCLUSIONS SHBRV strains have unique characteristics that may explain their exceptional association with human rabies but have little bearing on their lethality in mice. The pathogenicity of a particular virus, rather than its antigenic makeup, determines the outcome of immunization.
Collapse
Affiliation(s)
- B Dietzschold
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | | | | | | | |
Collapse
|
56
|
Abstract
The mode of action of quinolones involves interactions with both DNA gyrase, the originally recognised drug target, and topoisomerase IV, a related type II topoisomerase. In a given bacterium these 2 enzymes often differ in their relative sensitivities to many quinolones, and commonly DNA gyrase is more sensitive in gram-negative bacteria and topoisomerase IV more sensitive in gram-positive bacteria. Usually the more sensitive enzyme represents the primary drug target determined by genetic tests, but poorly understood exceptions have been documented. The formation of the ternary complex of quinolone, DNA, and either DNA gyrase or topoisomerase IV occurs through interactions in which quinolone binding appears to induce changes in both DNA and the topoisomerase that occur separately from the DNA cleavage that is the hallmark of quinolone action. X-ray crystallographic studies of a fragment of the gyrase A subunit, as well as of yeast topoisomerase IV, which has homology to the subunits of both DNA gyrase and topoisomerase IV, have revealed domains that are likely to constitute quinolone binding sites, but no topoisomerase crystal structures that include DNA and quinolone have been reported to date. Inhibition of DNA synthesis by quinolones requires the targeted topoisomerase to have DNA cleavage capability, and collisions of the replication fork with reversible quinolone-DNA-topoisomerase complexes convert them to an irreversible form. However, the molecular factors that subsequently generate DNA double-strand breaks from the irreversible complexes and that probably initiate cell death have yet to be defined.
Collapse
Affiliation(s)
- D C Hooper
- Division of Infectious Diseases, Massachusetts General Hospital, Harvard Medical School, Boston 02114-2696, USA.
| |
Collapse
|
57
|
Eisenman LM, Brothers R, Tran MH, Kean RB, Dickson GM, Dietzschold B, Hooper DC. Neonatal Borna disease virus infection in the rat causes a loss of Purkinje cells in the cerebellum. J Neurovirol 1999; 5:181-9. [PMID: 10321982 DOI: 10.3109/13550289909022000] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Viral insults that occur during early postnatal periods, can affect neuronal systems which exhibit significant postnatal development, such as the cerebral cortex and cerebellum. Borna disease virus (BDV) is a single-strand RNA virus which replicates in the nervous system of many species after experimental inoculation and causes acute neurological disease. Neonatal rats infected with BDV do not mount an aggressive response to the virus like their adult counterparts, but instead develop a persistent BDV infection with less overt clinical sequelae. Recently, the cerebellum, a neural structure associated with regulation of motor behavior, and perhaps with higher cognitive functions, has been demonstrated to be a target of neonatal BDV infections in rats (Bautista et al, 1995). In the present study neonatal rats were infected with BDV and their cerebella were analyzed histologically and immunohistochemically at 7 months of age. The cerebella of infected animals were reduced in size but normal foliation and laminar organization was present. However, as visualized with immunohistochemistry for the Purkinje cell-specific antigen calbindin, there were numerous gaps within the Purkinje cell layer and in the molecular layer which contains the Purkinje cell dendritic trees. We estimated the number of Purkinje cells and found there was an approximately 75% loss of PC in adult rats neonatally infected with BDV. These results suggest that neonatal BDV infection may either (1) target the PC and cause the death of these cells directly or (2) acts indirectly by triggering an immune response which is then responsible for the loss of these cells.
Collapse
Affiliation(s)
- L M Eisenman
- Department of Pathology, Anatomy and Cell Biology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | | | | | | | | | |
Collapse
|
58
|
Fournier B, Gravel A, Hooper DC, Roy PH. Strength and regulation of the different promoters for chromosomal beta-lactamases of Klebsiella oxytoca. Antimicrob Agents Chemother 1999; 43:850-5. [PMID: 10103190 PMCID: PMC89216 DOI: 10.1128/aac.43.4.850] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The two groups of chromosomal beta-lactamases from Klebsiella oxytoca (OXY-1 and OXY-2) can be overproduced 73- to 223-fold, due to point mutations in the consensus sequences of their promoters. The different versions of promoters from blaOXY-1 and blaOXY-2 were cloned upstream of the chloramphenicol acetyltransferase (CAT) gene of pKK232-8, and their relative strengths were determined in Escherichia coli and in K. oxytoca. The three different mutations in the OXY beta-lactamase promoters resulted in a 4- to 31-fold increase in CAT activity compared to that of the wild-type promoter. The G-->T transversion in the first base of the -10 consensus sequence caused a greater increase in the promoter strength of the wild-type promoter than the two other principal mutations (a G-to-A transition of the fifth base of the -10 consensus sequence and a T-to-A transversion of the fourth base of the -35 sequence). The strength of the promoter carrying a double mutation (transition in the Pribnow box and the transversion in the -35 hexamer) was increased 15- to 61-fold in comparison to that of the wild-type promoter. A change from 17 to 16 bp between the -35 and -10 consensus sequences resulted in a ninefold decrease of the promoter strength. The expression of the blaOXY promoter in E. coli differs from that in K. oxytoca, particularly for promoters carrying strong mutations. Furthermore, the blaOXY promoter appears not to be controlled by DNA supercoiling or an upstream curved DNA, but it is dependent on the gene copy number.
Collapse
Affiliation(s)
- B Fournier
- Laboratoire et Service d'Infectiologie, Centre Hospitalier de l'Université Laval, Sainte-Foy Québec, Canada.
| | | | | | | |
Collapse
|
59
|
Röhrenbeck AM, Bette M, Hooper DC, Nyberg F, Eiden LE, Dietzschold B, Weihe E. Upregulation of COX-2 and CGRP expression in resident cells of the Borna disease virus-infected brain is dependent upon inflammation. Neurobiol Dis 1999; 6:15-34. [PMID: 10078970 DOI: 10.1006/nbdi.1998.0225] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Infection of immunocompetent adult rats with Borna disease virus (BDV) causes severe encephalitis and neural dysfunction. The expression of COX-2 and CGRP, genes previously shown to be implicated in CNS disease and peripheral inflammation, was dramatically upregulated in the cortical neurons of acutely BDV-infected rats. Neuronal COX-2 and CGRP upregulation was predominantly seen in brain areas where ED1-positive macrophages/microglia accumulated. In addition, COX-2 expression was strongly induced in brain endothelial cells and the number of COX-2 immunoreactive microglial cells was increased. In contrast, despite increased expression of viral antigens, neither COX-2 nor CGRP expression was altered in the CNS of BDV-infected rats treated with dexamethasone, or tolerant to BDV. Thus, increased CGRP and COX-2 expression in the BDV-infected brain is the result of the inflammatory response and likely to be involved in the pathogenesis of virus-induced encephalitis.
Collapse
Affiliation(s)
- A M Röhrenbeck
- Institute of Anatomy and Cell Biology, Philipps University Marburg, Germany
| | | | | | | | | | | | | |
Collapse
|
60
|
Morimoto K, Hooper DC, Spitsin S, Koprowski H, Dietzschold B. Pathogenicity of different rabies virus variants inversely correlates with apoptosis and rabies virus glycoprotein expression in infected primary neuron cultures. J Virol 1999; 73:510-8. [PMID: 9847357 PMCID: PMC103858 DOI: 10.1128/jvi.73.1.510-518.1999] [Citation(s) in RCA: 216] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/1998] [Accepted: 09/23/1998] [Indexed: 11/20/2022] Open
Abstract
The mouse-adapted rabies virus strain CVS-24 has stable variants, CVS-B2c and CVS-N2c, which differ greatly in their pathogenicity for normal adult mice and in their ability to infect nonneuronal cells. The glycoprotein (G protein), which has previously been implicated in rabies virus pathogenicity, shows substantial structural differences between these variants. Although prior studies have identified antigenic site III of the G protein as the major pathogenicity determinant, CVS-B2c and CVS-N2c do not vary at this site. The possibility that pathogenicity is inversely related to G protein expression levels is suggested by the finding that CVS-B2c, the less pathogenic variant, expresses at least fourfold-higher levels of G protein than CVS-N2c in infected neurons. Although there is some difference between CVS-B2c- and CVS-N2c-infected neurons in G protein mRNA expression levels, the differential expression of G protein appears to be largely determined by posttranslational mechanisms that affect G protein stability. Pulse-chase experiments indicated that the G protein of CVS-B2c is degraded more slowly than that of CVS-N2c. The accumulation of G protein correlated with the induction of programmed cell death in CVS-B2c-infected neurons. The extent of apoptosis was considerably lower in CVS-N2c-infected neurons, where G protein expression was minimal. While nucleoprotein (N protein) expression levels were similar in neurons infected with either variant, the transport of N protein into neuronal processes was strongly inhibited in CVS-B2c-infected cells. Thus, downregulation of G protein expression in neuronal cells evidently contributes to rabies virus pathogenesis by preventing apoptosis and the apparently associated failure of the axonal transport of N protein.
Collapse
Affiliation(s)
- K Morimoto
- Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-6799, USA
| | | | | | | | | |
Collapse
|
61
|
|
62
|
Abstract
The quinolone antimicrobials are the class of inhibitors of bacterial topoisomerases that has been developed most fully for clinical use in human medicine. Initial members of the class had their greatest potency against Gram-negative bacteria, but newly developed members have exhibited increased potency against Gram-positive bacteria and soon agents will be available with additional activity against anaerobic bacteria, providing a broad spectrum of potency. After nalidixic acid, the earliest member of the class which was used for treatment of urinary tract infections, the later fluoroquinolone congeners have had sufficient potency, absorption, and distribution into tissue for additional uses in treatment of sexually transmitted diseases, infections of the gastrointestinal tract, respiratory tract, skin, and bones and joints. Tolerability of these agents in usual doses has been good. Acquired bacterial resistance resulting from clinical uses has occurred in particular among staphylococci and Pseudomonas aeruginosa. Intense drug use and ability of resistant pathogens to spread have also contributed to development of resistance in initially more susceptible pathogens such as Escherichia coli and Neisseria gonorrhoeae in certain settings. Preservation of the considerable clinical utility of the quinolone class for the long term will be affected by the extent to which their use is judicious.
Collapse
Affiliation(s)
- D C Hooper
- Infectious Disease Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114-2696, USA.
| |
Collapse
|
63
|
Dietzschold B, Hooper DC. Human diploid cell culture rabies vaccine (HDCV) and purified chick embryo cell culture rabies vaccine (PCECV) both confer protective immunity against infection with the silver-haired bat rabies virus strain (SHBRV). Vaccine 1998; 16:1656-9. [PMID: 9713943 DOI: 10.1016/s0264-410x(98)00064-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The demonstration of extensive differences in the antigenic makeups of the silver-haired bat rabies virus (SHBRV) and canine rabies virus (COSRV) strains raised concerns as to whether current licensed rabies vaccines are sufficiently protective against SHBRV. NIH mouse protection test results show that both the human diploid cell culture rabies vaccine (HDCV) and the purified chicken embryo cell rabies vaccine (PCECV) protected against lethal infection with SHBRV as well as the canine rabies strain COSRV. However, in this investigation, the potencies of both vaccines in mice were found to be significantly higher for COSRV than for SHBRV. The in vivo protection data are confirmed by in vitro virus neutralizing antibody (VNA) test results which demonstrate that mice immunized with HDCV or PCECV develop significantly higher VNA titres against COSRV than against SHBRV. In contrast, VNA tests of sera from individuals immunized with HDCV or PCECV showed that humans, as opposed to mice, develop significantly higher VNA titres against SHBRV than against COSRV. These data suggest that HDCV and PCECV will protect humans against infection with the silver-haired but rabies virus strain in addition to canine rabies virus strains.
Collapse
Affiliation(s)
- B Dietzschold
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | |
Collapse
|
64
|
Ng EW, Samiy N, Ruoff KL, Cousins FV, Hooper DC, von Gunten S, D'Amico DJ, Baker AS. Treatment of experimental Staphylococcus epidermidis endophthalmitis with oral trovafloxacin. Am J Ophthalmol 1998; 126:278-87. [PMID: 9727522 DOI: 10.1016/s0002-9394(98)00157-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE To investigate the ocular pharmacokinetics and efficacy of oral trovafloxacin, a novel fluoroquinolone antibiotic, in Staphylococcus epidermidis endophthalmitis. METHODS Albino rabbits (n = 20) were infected with an intravitreal inoculum of S epidermidis (1.0 x 10(8) colony-forming units [CFU/0.1 ml) and 24 hours later received a single oral dose of trovafloxacin (250 mg/kg). Serum and intraocular samples from infected and control (noninfected) eyes were obtained up to 24 hours after antibiotic administration for measurement of trovafloxacin levels. A second group of rabbits (n = 72) was infected intraocularly and randomized 24 hours later to oral trovafloxacin (250 mg/kg twice a day) for 6 days or no treatment (control). Treatment efficacy was assessed by vitreous culture, clinical examination, and histopathology. RESULTS Following a single dose of trovafloxacin, maximal vitreous levels were achieved at 8 hours in infected eyes, with a penetration ratio of 36%. Vitreous levels were greater than 15 times the minimum inhibitory concentration of the strain employed. In animals with established endophthalmitis, treated eyes were sterilized after 5 days (P = .0495) compared with control eyes, which autosterilized at 14 days. Clinical and histologic examination revealed significant amelioration of anterior segment inflammation in treated eyes, although severe destruction of posterior segment structures occurred in both groups after 6 days of therapy. CONCLUSIONS These data support trovafloxacin as a potential oral agent for treatment or prophylaxis of S epidermidis endophthalmitis, although retinal alterations that occur over the period required for vitreous sterilization suggest that it will not replace intravitreal therapy in established endophthalmitis.
Collapse
Affiliation(s)
- E W Ng
- Massachusetts Eye and Ear Infirmary, and the Department of Ophthalmology, Harvard Medical School 02114-3096, USA
| | | | | | | | | | | | | | | |
Collapse
|
65
|
Fournier B, Hooper DC. Effects of mutations in GrlA of topoisomerase IV from Staphylococcus aureus on quinolone and coumarin activity. Antimicrob Agents Chemother 1998; 42:2109-12. [PMID: 9687416 PMCID: PMC105875 DOI: 10.1128/aac.42.8.2109] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The grlA genes of Staphylococcus aureus ISP794 (wild type), MT5224c4 (grlA [Phe-80]), MT5224c2 (grlA [Pro-116]), and MT111 (grlA [Glu-116]) were cloned in pSK950, a shuttle vector, and introduced into S. aureus strains derived from strain RN4220. The mutations at position 116 of GrlA (Ala-->Pro or Glu) caused an increase in the level of fluoroquinolone resistance and a decrease in the level of coumarin susceptibility, whereas the mutation at position 80 (Ser-->Phe) caused only an increase in the level of fluoroquinolone resistance. In multicopy alleles, both types of mutations were codominant for fluoroquinolone resistance, and mutations at position 116 were also codominant for coumarin resistance.
Collapse
Affiliation(s)
- B Fournier
- Infectious Disease Division and Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114-2696, USA
| | | |
Collapse
|
66
|
Abstract
Topoisomerases are ubiquitous enzymes necessary for controlling the interlinking and twisting of DNA molecules. Among the four topoisomerases identified in eubacteria, two, DNA gyrase and topoisomerase IV have been exploited by nature and the pharmaceutical industry as antibacterial targets. Natural products that are inhibitors of one or both of these topoisomerases include the coumarin and cyclothialidine classes, which interfere with adenosine triphosphate hydrolysis, cinodine, flavones, and terpenoid derivatives. The plasmid-encoded bacterial peptides micron B17 and CcdB also inhibit DNA gyrase. The quinolones, a synthetic class of antibacterials that act on both DNA gyrase and topoisomerase IV have had the broadest clinical applications, however. Quinolone congeners differ in their relative potencies for DNA gyrase and topoisomerase IV Studies of an expanding set of resistant mutant enzymes and the crystal structure of the homologous enzyme in yeast have contributed to our understanding of interactions of these drugs with topoisomerase-DNA complexes and the ways in which mutations effect resistance.
Collapse
Affiliation(s)
- D C Hooper
- Infectious Disease Division, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| |
Collapse
|
67
|
Abstract
Bacteremic nocardiosis is reported rarely. We discuss 4 recent cases seen at our institution and 32 other cases described in the English literature. We found that patients with bacteremic nocardiosis were similar in presentation, risk factors, course, and therapeutic outcome to nonbacteremic patients with nocardiosis. The presence of endovascular foreign bodies appeared to be the only unique risk factor associated with bacteremic illness. Seeding of the central nervous system appeared to be relatively uncommon. Thirty percent of patients with nocardemia had concomitant bacteremia with other pathogens, mostly Gram-negative organisms. Nocardia grew in a variety of growth media, and the median incubation time to detection was 4 days. Fifty percent of patients with Nocardia bacteremia died. Positive blood cultures were a preterminal finding in the fatal, acute cases and occurred relatively early in the subacute, nonfatal cases. Poor outcome seemed to correlate with acute onset of nocardiosis (duration less than 1 month), late identification of nocardemia, involvement of more than 2 sites, and the lack of treatment with a sulfonamide-containing regimen.
Collapse
Affiliation(s)
- D P Kontoyiannis
- Infectious Disease Division, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| | | | | |
Collapse
|
68
|
Hooper DC, Morimoto K, Bette M, Weihe E, Koprowski H, Dietzschold B. Collaboration of antibody and inflammation in clearance of rabies virus from the central nervous system. J Virol 1998; 72:3711-9. [PMID: 9557653 PMCID: PMC109593 DOI: 10.1128/jvi.72.5.3711-3719.1998] [Citation(s) in RCA: 184] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/1997] [Accepted: 01/23/1998] [Indexed: 02/07/2023] Open
Abstract
To investigate the involvement of various cellular and humoral aspects of immunity in the clearance of rabies virus from the central nervous system, (CNS), we studied the development of clinical signs and virus clearance from the CNS in knockout mice lacking either B and T cells, CD8+ cytotoxic T cells, B cells, alpha/beta interferon (IFN-alpha/beta) receptors, IFN-gamma receptors, or complement components C3 and C4. Following intranasal infection with the attenuated rabies virus CVS-F3, normal adult mice of different genetic backgrounds developed a transient disease characterized by loss of body weight and appetite depression which peaked at 13 days postinfection (p.i.). While these animals had completely recovered by day 21 p.i., mice lacking either B and T cells or B cells alone developed a progressive disease and succumbed to infection. Mice lacking either CD8+ T cells, IFN receptors, or complement components C3 and C4 showed no significant differences in the development of clinical signs by comparison with intact counterparts having the same genetic background. However, while infectious virus and viral RNA could be detected in normal control mice only until day 8 p.i., in all of the gene knockout mice studied except those lacking C3 and C4, virus infection persisted through day 21 p.i. Analysis of rabies virus-specific antibody production together with histological assessment of brain inflammation in infected animals revealed that clearance of CVS-F3 by 21 days p.i. correlated with both a strong inflammatory response in the CNS early in the infection (day 8 p.i.), and the rapid (day 10 p.i.) production of significant levels of virus-neutralizing antibody (VNA). These studies confirm that rabies VNA is an absolute requirement for clearance of an established rabies virus infection. However, for the latter to occur in a timely fashion, collaboration between VNA and inflammatory mechanisms is necessary.
Collapse
Affiliation(s)
- D C Hooper
- Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107-6799, USA
| | | | | | | | | | | |
Collapse
|
69
|
Fridkin SK, Yokoe DS, Whitney CG, Onderdonk A, Hooper DC. Epidemiology of a dominant clonal strain of vancomycin-resistant Enterococcus faecium at separate hospitals in Boston, Massachusetts. J Clin Microbiol 1998; 36:965-70. [PMID: 9542917 PMCID: PMC104669 DOI: 10.1128/jcm.36.4.965-970.1998] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In 1996, the dominant (43%) strain of vancomycin-resistant enterococci (VRE; type A) at Massachusetts General Hospital was identified at Brigham and Women's Hospital (BWH). To characterize the epidemiology of infection with type A isolates of VRE at BWH, we collected demographic and clinical data for all patients from whom VRE were isolated from a clinical specimen through September 1996. The first clinical isolates from all BWH patients from whom VRE were isolated were typed by pulsed-field gel electrophoresis of SmaI digests of chromosomal DNA. Among patients hospitalized after the first patient at BWH infected with a type A isolate of VRE was identified, exposures were compared between patients who acquired type A isolates of VRE and those who acquired other types of VRE. Isolates from 99 patients identified to have acquired VRE were most commonly from blood (n = 27), urine (n = 19), or wounds (n = 19). Three months after the index patient arrived at BWH and at a time when > or =12 types of strains of VRE were present, type A isolates of VRE became dominant; 39 of 75 (52%) of the study cohort had acquired type A isolates of VRE. We found no association between the acquisition of type A isolates of VRE and transfer from another institution or temporal overlap by service, ward, or floor with patients known to have acquired type A isolates of VRE. By multivariate analysis, only residence in the medical intensive care unit (adjusted odds ratio [OR], 3.2; 95% confidence interval [CI], 1.4 to 107) and the receipt of two or more antibiotics per patient-day (adjusted OR, 12.2; 95% CI, 1.2 to 9.0) were associated with the acquisition of strain A. This strain of VRE, dominant at two Boston hospitals, was associated with intensity of antibiotic exposures (i.e., two or more antibiotics per patient-day). We hypothesize that this strain may have unidentified properties providing a mechanism favoring its spread and dominance over other extant isolates, and further studies are needed to define these properties.
Collapse
Affiliation(s)
- S K Fridkin
- Infectious Disease Division, Massachusetts General Hospital, Boston 02114-2696, USA
| | | | | | | | | |
Collapse
|
70
|
Abstract
Passage of the mouse-adapted rabies virus strain CVS-24 (where CVS is challenge virus standard) in BHK cells results in the rapid selection of a dominant variant designated CVS-B2c that differs genotypically and phenotypically from the dominant variant CVS-N2c present in mouse-brain- or neuroblastoma-cell-passaged CVS-24. The glycoprotein of CVS-B2c has 10 amino acid substitutions compared with that of CVS-N2c. Because CVS-B2c can be reproducibly selected in BHK cells, it is likely to be a conserved minor subpopulation of CVS-24. CVS-N2c is more neurotropic in vitro and in vivo than CVS-B2c, which replicates more readily in nonneuronal cells in vitro and in vivo. These characteristics appear to be relevant to the pathogenicity of the two variants. CVS-N2c is more pathogenic for adult mice than CVS-B2c. In contrast, CVS-B2c is more pathogenic for neonatal mice. These differences in pathogenicity are reflected in the selection pattern when mixtures of CVS-N2c and CVS-B2c were used to infect neonatal and adult mice. Although CVS-N2c was highly selected in adult mice, no selection for either variant was seen in neonates, suggesting that certain aspects of development, such as maturation of the nervous and immune systems, may contribute to the selection process. We speculate that the existence of different variants within a rabies virus strain may facilitate the virus in overcoming barriers to its spread, both within the host and between species.
Collapse
Affiliation(s)
- K Morimoto
- Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | |
Collapse
|
71
|
Modelska A, Dietzschold B, Sleysh N, Fu ZF, Steplewski K, Hooper DC, Koprowski H, Yusibov V. Immunization against rabies with plant-derived antigen. Proc Natl Acad Sci U S A 1998; 95:2481-5. [PMID: 9482911 PMCID: PMC19382 DOI: 10.1073/pnas.95.5.2481] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/1997] [Indexed: 02/06/2023] Open
Abstract
We previously demonstrated that recombinant plant virus particles containing a chimeric peptide representing two rabies virus epitopes stimulate virus neutralizing antibody synthesis in immunized mice. We show here that mice immunized intraperitoneally or orally (by gastric intubation or by feeding on virus-infected spinach leaves) with engineered plant virus particles containing rabies antigen mount a local and systemic immune response. After the third dose of antigen, given intraperitoneally, 40% of the mice were protected against challenge infection with a lethal dose of rabies virus. Oral administration of the antigen stimulated serum IgG and IgA synthesis and ameliorated the clinical signs caused by intranasal infection with an attenuated rabies virus strain.
Collapse
Affiliation(s)
- A Modelska
- Biotechnology Foundation Laboratories at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | | | | | | | | | |
Collapse
|
72
|
Abstract
Rabies virus nucleoprotein (N) encapsidates negative-strand genomic RNA in vivo, and this RNA-N complex, together with the nominal viral phosphoprotein (P) and RNA polymerase (L), forms the active cytoplasmic ribonucleoprotein (RNP) complex in virus-infected cells and the RNP core in virus particles. The RNP complex is capable of initiating viral RNA transcription and replication in vivo and in vitro. To obtain insight into the events leading to the formation of the RNA-N complex, we have investigated the interaction between rabies virus N and the positive-strand leader RNA transcript. Binding studies revealed that recombinant N binds preferentially to rabies virus leader RNA and that N binding to leader RNA was 5 to 10 times stronger than to nonleader RNA. Encapsidation of leader RNA by N could be competetively inhibited by unlabeled leader RNA but not by nonleader RNA. Furthermore, N protein encapsidation of nonleader RNA but not the leader RNA was inhibited when P was simultaneously added into the encapsidation reaction, indicating that P helps confer the specificity of leader RNA encapsidation by N. The initiation signal for leader RNA encapsidation by N has been mapped to nucleotides 20-30 of the RNA sequence which is A rich. Studies with N-deletion mutants indicate that the intact N is required to encapsidate RNA, since deletion of amino acid residues from either the N- or the C-terminus of N abolishes the ability of N to encapsidate leader RNA.
Collapse
Affiliation(s)
- J Yang
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
| | | | | | | | | | | |
Collapse
|
73
|
Hooper DC, Spitsin S, Kean RB, Champion JM, Dickson GM, Chaudhry I, Koprowski H. Uric acid, a natural scavenger of peroxynitrite, in experimental allergic encephalomyelitis and multiple sclerosis. Proc Natl Acad Sci U S A 1998; 95:675-80. [PMID: 9435251 PMCID: PMC18479 DOI: 10.1073/pnas.95.2.675] [Citation(s) in RCA: 422] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Uric acid, the naturally occurring product of purine metabolism, is a strong peroxynitrite scavenger, as demonstrated by the capacity to bind peroxynitrite but not nitric oxide (NO) produced by lipopolysaccharide-stimulated cells of a mouse monocyte line. In this study, we used uric acid to treat experimental allergic encephalomyelitis (EAE) in the PLSJL strain of mice, which develop a chronic form of the disease with remissions and exacerbations. Uric acid administration was found to have strong therapeutic effects in a dose-dependent fashion. A regimen of four daily doses of 500 mg/kg uric acid was required to promote long-term survival regardless of whether treatment was initiated before or after the clinical symptoms of EAE had appeared. The requirement for multiple doses is likely to be caused by the rapid clearance of uric acid in mice which, unlike humans, metabolize uric acid a step further to allantoin. Uric acid treatment also was found to diminish clinical signs of a disease resembling EAE in interferon-gamma receptor knockout mice. A possible association between multiple sclerosis (MS), the disease on which EAE is modeled, and uric acid is supported by the finding that patients with MS have significantly lower levels of serum uric acid than controls. In addition, statistical evaluation of more than 20 million patient records for the incidence of MS and gout (hyperuricemic) revealed that the two diseases are almost mutually exclusive, raising the possibility that hyperuricemia may protect against MS.
Collapse
Affiliation(s)
- D C Hooper
- Center for Neurovirology, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA.
| | | | | | | | | | | | | |
Collapse
|
74
|
Fournier B, Hooper DC. Mutations in topoisomerase IV and DNA gyrase of Staphylococcus aureus: novel pleiotropic effects on quinolone and coumarin activity. Antimicrob Agents Chemother 1998; 42:121-8. [PMID: 9449271 PMCID: PMC105466 DOI: 10.1128/aac.42.1.121] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Previous studies have shown that topoisomerase IV and DNA gyrase interact with quinolones and coumarins in different ways. The MICs of coumarins (novobiocin and coumermycin) for MT5, a Staphylococcus aureus nov mutant, are higher than those for wild-type strains. Sequencing the gyrB gene encoding one subunit of the DNA gyrase revealed the presence of a double mutation likely to be responsible for this resistance: at codon 102 (Ile to Ser) and at codon 144 (Arg to Ile). For single-step flqA mutant MT5224c9, previously selected on ciprofloxacin, the fluoroquinolone MIC was higher and the coumarin MIC was lower than those for its parent, MT5. Sequencing the grlB and grlA genes of topoisomerase IV of MT5224c9 showed a single Asn-470-to-Asp mutation in GrlB. Genetic outcrosses by transformation with chromosomal DNA and introduction of plasmids carrying either the wild-type or the mutated grlB gene indicated that this mutation causes both increased MICs of fluoroquinolones and decreased MICs of coumarins and that the mutant grlB allele is codominant for both phenotypes with multicopy alleles. Integration of these plasmids into the chromosome confirmed the codominance of fluoroquinolone resistance, but grlB+ appeared dominant over grlB (Asp-470) for coumarin resistance. Finally, the gyrA (Leu-84) mutation previously described as silent for fluoroquinolone resistance increased the MIC of nalidixic acid, a nonfluorinated quinolone. Combining the grlA (Phe-80) and grlB (Asp-470) mutations with this gyrA mutation also had differing effects. The findings indicate that alterations in topoisomerases may have pleiotropic effects on different classes of inhibitors as well as on inhibitors within the same class. A full understanding of drug action and resistance at the molecular level must take into account both inhibitor structure-activity relationships and the effects of different classes of topoisomerase mutants.
Collapse
Affiliation(s)
- B Fournier
- Infectious Disease Division, Massachusetts General Hospital, Harvard Medical School, Boston 02114-2696, USA
| | | |
Collapse
|
75
|
Pegues DA, Colby C, Hibberd PL, Cohen LG, Ausubel FM, Calderwood SB, Hooper DC. The epidemiology of resistance to ofloxacin and oxacillin among clinical coagulase-negative staphylococcal isolates: analysis of risk factors and strain types. Clin Infect Dis 1998; 26:72-9. [PMID: 9455512 DOI: 10.1086/516270] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Coagulase-negative staphylococci are important nosocomial pathogens that increasingly are resistant to oxacillin and fluoroquinolones. To determine predictors of acquisition of oxacillin and ofloxacin resistance, we prospectively identified 150 patients from whose clinical specimens coagulase-negative staphylococci were isolated that differed in susceptibility to oxacillin and ofloxacin. In multivariate analysis, isolation of ofloxacin-resistant coagulase-negative staphylococci was associated with receipt of aminoglycosides (odds ratio [OR] = 8.45; 95% confidence interval [CI] = 2.10-34.1; P = .001) and fluoroquinolones (OR = 11.50; 95% CI = 4.15-31.6; P < .001) within 30 days; oxacillin resistance was associated with prior receipt of beta-lactam agents (OR = 5.99; 95% CI = 2.91-12.3; P < .001). Among oxacillin-resistant strains, there was heterogeneity of pulsed-field gel electrophoresis (PFGE) types, and no type was common between ofloxacin-resistant and ofloxacin-susceptible strains. Thus ofloxacin resistance may have emerged de novo among diverse oxacillin-resistant strains following the selection pressures of antimicrobial therapy. In contrast, 50% of patients with oxacillin-susceptible/ofloxacin-resistant strains had one of two PFGE types, a finding suggesting that person-to-person transmission resulted in the dissemination of some of these strains.
Collapse
Affiliation(s)
- D A Pegues
- Department of Pharmacy, Massachusetts General Hospital, Harvard Medical School, Boston 02114-2696, USA
| | | | | | | | | | | | | |
Collapse
|
76
|
Pegues DA, Pegues CF, Hibberd PL, Ford DS, Hooper DC. Emergence and dissemination of a highly vancomycin-resistant vanA strain of Enterococcus faecium at a large teaching hospital. J Clin Microbiol 1997; 35:1565-70. [PMID: 9163483 PMCID: PMC229788 DOI: 10.1128/jcm.35.6.1565-1570.1997] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We prospectively identified patients at the Massachusetts General Hospital from whom vancomycin-resistant enterococci (VRE) were isolated from a clinical specimen from 1 January 1991 through 31 December 1995. VRE strains were available from 139 (82%) of the 169 patients with clinical cases. Of these, 39 (28%) were identical or closely related by pulsed-field gel electrophoresis (i.e., VRE type A strain), including 38 (43%) of 89 VRE strains in 1995. By multivariate analysis, acquisition of the VRE type A strain was associated with receipt of clindamycin (odds ratio [OR] = 10.5), 15 or more days of hospitalization before the first isolation of VRE (OR = 2.9), and residence on one of the general medical floors (OR = 7.8). The VRE type A strain was a vanA strain of Enterococcus faecium and was highly resistant to all antimicrobial agents tested except chloramphenicol. These findings document the rapid dissemination of a highly resistant strain of E. faecium among patients and among other extant VRE strains at the Massachusetts General Hospital in 1995.
Collapse
Affiliation(s)
- D A Pegues
- Infectious Disease Unit, Massachusetts General Hospital and Harvard Medical School, Boston 02114-2696, USA
| | | | | | | | | |
Collapse
|
77
|
Yusibov V, Modelska A, Steplewski K, Agadjanyan M, Weiner D, Hooper DC, Koprowski H. Antigens produced in plants by infection with chimeric plant viruses immunize against rabies virus and HIV-1. Proc Natl Acad Sci U S A 1997; 94:5784-8. [PMID: 9159151 PMCID: PMC20857 DOI: 10.1073/pnas.94.11.5784] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The coat protein (CP) of alfalfa mosaic virus was used as a carrier molecule to express antigenic peptides from rabies virus and HIV. The antigens were separately cloned into the reading frame of alfalfa mosaic virus CP and placed under the control of the subgenomic promoter of tobacco mosaic virus CP in the 30BRz vector. The in vitro transcripts of recombinant virus with sequences encoding the antigenic peptides were synthesized from DNA constructs and used to inoculate tobacco plants. The plant-produced protein (virus particles) was purified and used for immunization of mice. Both antigens elicited specific virus-neutralizing antibodies in immunized mice.
Collapse
Affiliation(s)
- V Yusibov
- Biotechnology Foundation Laboratories, Thomas Jefferson University, 1020 Locust Street, Room 346 JAH, Philadelphia, PA 19107, USA.
| | | | | | | | | | | | | |
Collapse
|
78
|
Bisognano C, Vaudaux PE, Lew DP, Ng EY, Hooper DC. Increased expression of fibronectin-binding proteins by fluoroquinolone-resistant Staphylococcus aureus exposed to subinhibitory levels of ciprofloxacin. Antimicrob Agents Chemother 1997; 41:906-13. [PMID: 9145842 PMCID: PMC163823 DOI: 10.1128/aac.41.5.906] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Bacterial adhesion, which plays an important role in Staphylococcus aureus colonization and infection, may be altered by the presence of antibiotics or/and antibiotic resistance determinants. This study evaluated the effect of fluoroquinolone resistance determinants on S. aureus adhesion to solid-phase fibronectin, which is specifically mediated by two surface-located fibronectin-binding proteins. Five isogenic mutants, derived from strain NCTC 8325 and expressing various levels of quinolone resistance, were tested in an in vitro bacterial adhesion assay with polymethylmethacrylate coverslips coated with increasing amounts of fibronectin. These strains contained single or combined mutations in the three major loci contributing to fluoroquinolone resistance, namely, grlA, gyrA, and flqB, which code for altered topoisomerase IV, DNA gyrase, and increased norA-mediated efflux of fluoroquinolones, respectively. Adhesion characteristics of the different quinolone-resistant mutants grown in the absence of fluoroquinolone showed only minor differences from those of parental strains. However, more important changes in adhesion were exhibited by mutants highly resistant to quinolones following their exponential growth in the presence of one-quarter MIC of ciprofloxacin. Increased bacterial adhesion of the highly quinolone-resistant mutants, which contained combined mutations in grlA and gyrA, was associated with and explained by the overexpression of their fibronectin-binding proteins as assessed by Western ligand affinity blotting. These findings contradict the notion that subinhibitory concentrations of antibiotics generally decrease the expression of virulence factors by S. aureus. Perhaps the increased adhesion of S. aureus strains highly resistant to fluoroquinolones contributes in part to that emergence in clinical settings.
Collapse
Affiliation(s)
- C Bisognano
- Division of Infectious Diseases, University Hospital, Geneva, Switzerland
| | | | | | | | | |
Collapse
|
79
|
Richt JA, Alexander RC, Herzog S, Hooper DC, Kean R, Spitsin S, Bechter K, Schüttler R, Feldmann H, Heiske A, Fu ZF, Dietzschold B, Rott R, Koprowski H. Failure to detect Borna disease virus infection in peripheral blood leukocytes from humans with psychiatric disorders. J Neurovirol 1997; 3:174-8. [PMID: 9111180 DOI: 10.3109/13550289709015807] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The presence of antibodies reactive with Borna disease virus (BDV) in the sera of some patients with certain psychiatric illnesses has been taken as evidence that this veterinary neurotrophic virus may occasionally infect and cause psychiatric disorders in humans. In this paper, we report the results of our studies concerning the detection of BDV-specific RNA in blood cells from patients with psychiatric diseases. Contrary to the results obtained by others, we have found no evidence for the presence of BDV-RNA in such cells. Prior work with BDV sequences in the assay environment, together with the exquisite sensitivity of RT-PCR, may account for the sporadic appearance of false positive evidence that BDV-specific RNA is present in human blood cells.
Collapse
Affiliation(s)
- J A Richt
- Institut für Virologie, Universitat Giessen, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
80
|
Hooper DC, Bagasra O, Marini JC, Zborek A, Ohnishi ST, Kean R, Champion JM, Sarker AB, Bobroski L, Farber JL, Akaike T, Maeda H, Koprowski H. Prevention of experimental allergic encephalomyelitis by targeting nitric oxide and peroxynitrite: implications for the treatment of multiple sclerosis. Proc Natl Acad Sci U S A 1997; 94:2528-33. [PMID: 9122229 PMCID: PMC20122 DOI: 10.1073/pnas.94.6.2528] [Citation(s) in RCA: 261] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
In this study we provide further evidence associating activated cells of the monocyte lineage with the lesions of multiple sclerosis (MS). Using a combination of immunohistochemistry and reverse transcriptase-dependent in situ polymerase chain reaction analysis, we have identified monocytes expressing inducible nitric oxide synthase (iNOS) to be prevalent in the plaque areas of post mortem brain tissue from patients with MS. In addition, we have obtained evidence of the nitration of tyrosine residues in brain areas local to accumulations of iNOS-positive cells. In parallel studies we have assessed the effects of inhibitors of iNOS induction, as well as scavengers of nitric oxide and peroxynitrite in the experimental allergic encephalomyelitis model. Significant therapeutic effects were seen with the inhibitor of iNOS induction, tricyclodecan-9-xyl-xanthogenate, a nitric oxide scavenger, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, and a peroxynitrite scavenger, uric acid. In particular, treatment with high doses of uric acid virtually prevented clinical symptoms of the disease. Together with our demonstration of the presence of activated macrophages expressing high levels of iNOS and evidence of peroxynitrite formation in brain tissue from patients with MS, these findings are of importance in the development of approaches to treat this disease.
Collapse
Affiliation(s)
- D C Hooper
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
81
|
Threlkeld SC, Hooper DC. Update on management of patients with Nocardia infection. Curr Clin Top Infect Dis 1997; 17:1-23. [PMID: 9189658] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S C Threlkeld
- Infectious Disease Unit, Harvard Medical School, Massachusetts General Hospital, Boston, USA
| | | |
Collapse
|
82
|
Breines DM, Ouabdesselam S, Ng EY, Tankovic J, Shah S, Soussy CJ, Hooper DC. Quinolone resistance locus nfxD of Escherichia coli is a mutant allele of the parE gene encoding a subunit of topoisomerase IV. Antimicrob Agents Chemother 1997; 41:175-9. [PMID: 8980775 PMCID: PMC163680 DOI: 10.1128/aac.41.1.175] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The locus nfxD, which contributes to high-level quinolone resistance in Escherichia coli KF111b (gyrAr nfxB nfxD), is only expressed in the presence of a gyrA mutation, and maps to the region of the parC and parE genes, was outcrossed into strain KF130, creating strain DH161 (gyrAr nfxD). DNA sequence analysis of DH161 revealed no changes in the topoisomerase IV parC quinolone resistance-determining region but did identify a single T-to-A mutation in parE at codon 445, leading to a change from Leu to His. Full-length cloned parE+ partially complemented the resistance phenotype in KF111b and DH161, but did not complement the resistance phenotype in strain KF130 (gyrAr). No complementation was seen with cloned, truncated parE+. To confirm these findings, gyrAr was first outcrossed from KF130 into E. coli W3110parE10 [parE temperature sensitive(Ts)] and KL16. The transduced strains KL16 and W3110parE10 were subsequently transformed with plasmids containing cloned parE from DH161 or KL16. Cloned parE from DH161 increased norfloxacin resistance in the parE(Ts) background twofold at 30 degrees C and fourfold at 42 degrees C compared to those for cloned parE from KL16. The same experiment with a non-Ts background revealed a twofold increase in the norfloxacin MIC at both 30 and 42 degrees C. These data identify the nfxD conditional resistance locus as a mutant allele of parE. This report is the first of a quinolone-resistant parE mutant and confirms the role of topoisomerase IV as a secondary target of norfloxacin in E. coli.
Collapse
Affiliation(s)
- D M Breines
- Infectious Disease Unit, Massachusetts General Hospital, Boston 02114-2696, USA
| | | | | | | | | | | | | |
Collapse
|
83
|
Morimoto K, Hooper DC, Bornhorst A, Corisdeo S, Bette M, Fu ZF, Schäfer MK, Koprowski H, Weihe E, Dietzschold B. Intrinsic responses to Borna disease virus infection of the central nervous system. Proc Natl Acad Sci U S A 1996; 93:13345-50. [PMID: 8917593 PMCID: PMC24095 DOI: 10.1073/pnas.93.23.13345] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Immune cells invading the central nervous system (CNS) in response to Borna disease virus (BDV) antigens are central to the pathogenesis of Borna disease (BD). We speculate that the response of the resident cells of the brain to infection may be involved in the sensitization and recruitment of these inflammatory cells. To separate the responses of resident cells from those of cells infiltrating from the periphery, we used dexamethasone to inhibit inflammatory reactions in BD. Treatment with dexamethasone prevented the development of clinical signs of BD, and the brains of treated animals showed no neuropathological lesions and a virtual absence of markers of inflammation, cell infiltration, or activation normally seen in the CNS of BDV-infected rats. In contrast, treatment with dexamethasone exacerbated the expression of BDV RNA, which was paralleled by a similarly elevated expression of mRNAs for egr-1, c-fos, and c-jun. Furthermore, dexamethasone failed to inhibit the increase in expression of mRNAs for tumor necrosis factor alpha, macrophage inflammatory protein 1 beta, interleukin 6, and mob-1, which occurs in the CNS of animals infected with BDV. Our findings suggest that these genes, encoding transcription factors, chemokines, and proinflammatory cytokines, might be directly activated in CNS resident cells by BDV. This result supports the hypothesis that the initial phase of the inflammatory response to BDV infection in the brain may be dependent upon virus-induced activation of CNS resident cells.
Collapse
Affiliation(s)
- K Morimoto
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
84
|
Ng EY, Trucksis M, Hooper DC. Quinolone resistance mutations in topoisomerase IV: relationship to the flqA locus and genetic evidence that topoisomerase IV is the primary target and DNA gyrase is the secondary target of fluoroquinolones in Staphylococcus aureus. Antimicrob Agents Chemother 1996; 40:1881-8. [PMID: 8843298 PMCID: PMC163434 DOI: 10.1128/aac.40.8.1881] [Citation(s) in RCA: 177] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mutations in the flqA (formerly ofx/cfx) resistance locus of Staphylococcus aureus were previously shown to be common after first-step selections for resistance to ciprofloxacin and ofloxacin and to map on the S. aureus chromosome distinctly from gyrA, gyrB, and norA.grlA and grlB, the genes for the topoisomerase IV of S. aureus, were identified from a genomic lambda library on a common KpnI fragment, and grlB hybridized specifically with the chromosomal SmaI A fragment, which contains the flqA locus. Amplification of grlA sequences (codons 1 to 251) by PCRs from nine independent single-step flqA mutants, one multistep mutant, and the parent strain identified mutations encoding a change from Ser to Phe at position 80 in four mutants, a novel change from Ala to either Glu or Pro at position 116 in three mutants, and no change in three mutants. In the multistep mutant, another resistance locus, flqC, was mapped by transformation to the chromosomal SmaI G fragment by linkage to omega(ch::Tn551)1051 (58%) and nov (97.9%), which encodes resistance to novobiocin. This fragment contains the gyrA gene, and flqC mutants had a mutation in gyrA encoding a change from Ser to Leu at position 84, a change previously found in resistant clinical isolates. In genetic outcrosses, the flqC (gyrA) mutation expressed resistance only in flqA mutants, including those with both types of grla mutations. The silent mutant allele of gyrA was present in a flqA background and expressed resistance only upon introduction of a grlA mutation. At fourfold the MIC of ciprofloxacin, the bactericidal activity of ciprofloxacin was reduced in a grlA mutant and was abolished in gyrA grlA double mutants. These findings provide direct genetic evidence that topoisomerase IV is the primary target of current fluoroquinolones in S. aureus and that this effect may result from the greater sensitivity of topoisomerase IV relative to that of DNA gyrase to these agents. Furthermore, resistance from an altered DNA gyrase requires resistant topoisomerase IV for its expression.
Collapse
Affiliation(s)
- E Y Ng
- Infectious Disease Unit, Massachusetts General Hospital, Boston 02114-2696, USA.
| | | | | |
Collapse
|
85
|
Pegues CF, Pegues DA, Ford DS, Hibberd PL, Carson LA, Raine CM, Hooper DC. Burkholderia cepacia respiratory tract acquisition: epidemiology and molecular characterization of a large nosocomial outbreak. Epidemiol Infect 1996; 116:309-17. [PMID: 8666075 PMCID: PMC2271439 DOI: 10.1017/s0950268800052626] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
In 1994 we investigated a large outbreak of Burkholderia (formerly Pseudomonas) cepacia respiratory tract acquisition. A case patient was defined as any patient with at least one sputum culture from which B. cepacia was isolated from 1 January to 31 December 1994. Seventy cases were identified. Most (40 [61%]) occurred between 1 February and 31 March 1994; of these, 35 (86%) were mechanically ventilated patients, 30 of whom were in an intensive-care unit (ICU) when B. cepacia was first isolated. Compared with control patients who were mechanically ventilated in an ICU, these 30 case-patients were significantly more likely to have been ventilated for 2 or more days (30/30 v. 15/30; P < 0.001) or to have been intubated more than once (12/30 v. 2/30; OR = 9.3, 95% CI 1.6-68.8; P = 0.002) before the first isolation of B. cepacia. By multivariate analysis, the 35 mechanically ventilated case-patients were significantly more likely to have received a nebulized medication (OR = 11.9, 95% CI = 1.6-553.1; P < 0.001) and a cephalosporin antimicrobial (OR = 11.9, 95% CI = 1.6-553.1) in the 10 days before the first isolation of B. cepacia, compared with B. cepacia-negative control-patients matched by date and duration of most recent mechanical ventilation. Although B. cepacia was not cultured from medications or the hospital environment, all outbreak strains tested had an identical DNA restriction endonuclease digestion pattern by pulsed-field gel electrophoresis. Review of respiratory therapy procedures revealed opportunities for contamination of nebulizer reservoirs. This investigation suggests that careful adherence to standard procedures for administration of nebulized medications is essential to prevent nosocomial respiratory infections.
Collapse
Affiliation(s)
- C F Pegues
- Infection Control Unit, Massachusetts General Hospital, Boston 02114, USA
| | | | | | | | | | | | | |
Collapse
|
86
|
Morimoto K, Patel M, Corisdeo S, Hooper DC, Fu ZF, Rupprecht CE, Koprowski H, Dietzschold B. Characterization of a unique variant of bat rabies virus responsible for newly emerging human cases in North America. Proc Natl Acad Sci U S A 1996; 93:5653-8. [PMID: 8643632 PMCID: PMC39303 DOI: 10.1073/pnas.93.11.5653] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The silver-haired bat variant of rabies virus (SHBRV) has been identified as the etiological agent of a number of recent human rabies cases in the United States that are unusual in not having been associated with any known history of conventional exposure. Comparison of the different biological and biochemical properties of isolates of this virus with those of a coyote street rabies virus (COSRV) revealed that there are unique features associated with SHBRV. In vitro studies showed that, while the susceptibility of neuroblastoma cells to infection by both viruses was similar, the infectivity of SHBRV was much higher than that of COSRV in fibroblasts (BHK-21) and epithelial cells (MA-104), particularly when these cells were kept at 34 degrees C. At this temperature, low pH-dependent fusion and cell-to-cell spread of virus is seen in BHK-21 cells infected with SHBRV but not with COSRV. It appears that SHBRV may possess an unique cellular tropism and the ability to replicate at lower temperature, allowing a more effective local replication in the dermis. This hypothesis is supported by in vivo results which showed that while SHBRV is less neurovirulent than COSRV when administered via the intramuscular or intranasal routes, both viruses are equally neuroinvasive if injected intracranially or intradermally. Consistent with the above findings, the amino acid sequences of the glycoproteins of SHBRV and COSRV were found to have substantial differences, particularly in the region that contains the putative toxic loop, which are reflected in marked differences in their antigenic composition. Nevertheless, an experimental rabies vaccine based on the Pittman Moore vaccine strain protected mice equally well from lethal doses of SHBRV and COSRV, suggesting that currently used vaccines should be effective in the postexposure prophylaxis of rabies due to SHBRV.
Collapse
Affiliation(s)
- K Morimoto
- The Center for Neurovirology, Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | | | | | |
Collapse
|
87
|
Abstract
The survival of bacteria was evaluated in custom-made saline breast implants with integral injection ports in vitro and in 10 New Zealand White rabbits for Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Serratia marcescens. Pseudomonas and Serratia survived in vitro in saline-filled implants and multiplied 24-fold and 22-fold, respectively, from the initial inocula of 300 colony-forming units per cubic centimeter in 21 days. Serratia alone survived in saline implants placed on the dorsum of rabbits, proliferated 80-fold in 7 days, and tapered to 10-fold at the end of 3 weeks. Chemical analysis revealed the presence of glucose in fluid from the implants in the animal study (mean, 1.2 mg per deciliter; standard error of mean [SEM], 0.6) after 21 days and from human subjects (mean, 3.8 mg per deciliter; SEM, 1.0) after 8 months to 10 years. Serratia incubated in human breast implant fluid samples proliferated 7-fold to 30-fold greater than in the saline control in a nonaerated environment. We conclude that some bacteria are able to proliferate in saline in breast implants. Furthermore, their survival may be facilitated by a substance (i.e., glucose) that diffuses across the implant outer shell.
Collapse
Affiliation(s)
- N T Chen
- Department of Surgery, Massachusetts General Hospital, Boston 02114, USA
| | | | | | | |
Collapse
|
88
|
Truong QC, Ouabdesselam S, Hooper DC, Moreau NJ, Soussy CJ. Sequential mutations of gyrA in Escherichia coli associated with quinolone therapy. J Antimicrob Chemother 1995; 36:1055-9. [PMID: 8821606 DOI: 10.1093/jac/36.6.1055] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A clinical isolate of Escherichia coli HM73 (MIC norfloxacin 2 mg/L) was isolated during norfloxacin therapy from an urinary tract infection in a patient who had been previously treated with pipemidic acid and infected by E. coli HM72 (norfloxacin 0.25), known to harbour a substitution Ser 83-->Leu in the gyrA gene. No difference in accumulation of norfloxacin was found between the two strains. DNA gyrases were isolated by affinity chromatography and assayed for supercoiling activity in the presence of norfloxacin. The minimal effective doses (MEDs) were 20 mg/L, for HM72 and 80 for HM73. DNA sequencing identified in HM73, two mutations leading to substitutions Ser 83 to Leu and Asp 87 to Gly.
Collapse
Affiliation(s)
- Q C Truong
- Centre National de la Recherche Scientifique, Thiais, France
| | | | | | | | | |
Collapse
|
89
|
McGarvey PB, Hammond J, Dienelt MM, Hooper DC, Fu ZF, Dietzschold B, Koprowski H, Michaels FH. Expression of the rabies virus glycoprotein in transgenic tomatoes. Biotechnology (N Y) 1995; 13:1484-7. [PMID: 9636308 DOI: 10.1038/nbt1295-1484] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have engineered tomato plants (Lycopersicon esculentum Mill var. UC82b) to express a gene for the glycoprotein (G-protein), which coats the outer surface of the rabies virus. The recombinant constructs contained the G-protein gene from the ERA strain of rabies virus, including the signal peptide, under the control of the 35S promoter of cauliflower mosaic virus. Plants were transformed by Agrobacterium tumefaciens-mediated transformation of cotyledons and tissue culture on selective media. PCR confirmed the presence of the G-protein gene in plants surviving selection. Northern blot analysis indicated that RNA of the appropriate molecular weight was produced in both leaves and fruit of the transgenic plants. The recombinant G-protein was immunoprecipitated and detected by Western blot from leaves and fruit using different antisera. The G-protein expressed in tomato appeared as two distinct bands with apparent molecular mass of 62 and 60 kDa as compared to the 66 kDa observed for G-protein from virus grown in BHK cells. Electron microscopy of leaf tissue using immunogold-labeling and antisera specific for rabies G-protein showed localization of the G-protein to the Golgi bodies, vesicles, plasmalemma and cell walls of vascular parenchyma cells. In light of our previous demonstration that orally administered rabies G-protein from the same ERA strain elicits protective immunity in animals, these transgenic plants should provide a valuable tool for the development of edible oral vaccines.
Collapse
Affiliation(s)
- P B McGarvey
- Thomas Jefferson University, Department of Microbiology and Immunology, Philadelphia, PA 19107, USA.
| | | | | | | | | | | | | | | |
Collapse
|
90
|
Ouabdesselam S, Hooper DC, Tankovic J, Soussy CJ. Detection of gyrA and gyrB mutations in quinolone-resistant clinical isolates of Escherichia coli by single-strand conformational polymorphism analysis and determination of levels of resistance conferred by two different single gyrA mutations. Antimicrob Agents Chemother 1995; 39:1667-70. [PMID: 7486897 PMCID: PMC162804 DOI: 10.1128/aac.39.8.1667] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Twelve quinolone-resistant clinical isolates of Escherichia coli (nalidixic acid MICs, 64 to 512 micrograms/ml; norfloxacin MICs, 0.25 to 8 micrograms/ml) were transformed with plasmid pJSW101 carrying the gyrA+ gene and with plasmid pJB11 carrying the gyrB+ gene to examine the proportion of gyrA and gyrB mutations. Transformation with pJSW101 resulted in complementation (nalidixic acid MICs, 4 to 32 micrograms/ml; norfloxacin MICs, 0.06 to 0.25 micrograms/ml). In contrast, no change in MICs were observed after transformation with pJB11. A 418-bp fragment of gyrA from the 12 strains was amplified by PCR. Direct DNA sequencing of that fragment identified the causes of quinolone resistance in eight strains as a single point mutation leading to a substitution of the serine at position 83 (Ser-83) to Leu and in four strains as a single point mutation leading to a substitution of Asp-87 to Gly. Exchange of the fragment from one of these strains with that of gyrA+ and transformation of resistance with the hybrid gyrA plasmid indicated the contribution of Gly-87 to resistance and the stabilities of mutants containing GyrA (Gly-87). Thus, gyrA gene mutations are probably encountered more often than gyrB gene mutations in clinical isolates of E. coli. In addition, the substitution of Asp-87 to Gly can be encountered in such strains. On the basis of the level of resistance found in the fragment exchange experiment, the quinolone resistance attributable to Gly-87 appears to be comparable to that attributable to Leu-83. The levels of resistance found in the clinical isolates shown to have a Gly-87 mutation (nalidixic acid MICs, 64 to 512 micrograms/ml; norfloxacin MICs, 0.5 to 4 micrograms/ml) suggest that the Gly-87 mutation causes resistance at the level of the nalidixic acid MIC (64 micrograms/ml) or the norfloxacin MIC (0.5 micrograms/ml or less) and that the additional increments in resistance seen in the other strains with higher levels of resistance may be attributable to additional mutations. The single-strand conformational polymorphism analysis with PCR products readily detected te Leu-83 and Gly-87 mutations.
Collapse
Affiliation(s)
- S Ouabdesselam
- Centre Hospitalier Universitaire Henri Mondor, Créteil, France
| | | | | | | |
Collapse
|
91
|
Hooper DC, Ohnishi ST, Kean R, Numagami Y, Dietzschold B, Koprowski H. Local nitric oxide production in viral and autoimmune diseases of the central nervous system. Proc Natl Acad Sci U S A 1995; 92:5312-6. [PMID: 7539914 PMCID: PMC41684 DOI: 10.1073/pnas.92.12.5312] [Citation(s) in RCA: 142] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Because of the short half-life of NO, previous studies implicating NO in central nervous system pathology during infection had to rely on the demonstration of elevated levels of NO synthase mRNA or enzyme expression or NO metabolites such as nitrate and nitrite in the infected brain. To more definitively investigate the potential causative role of NO in lesions of the central nervous system in animals infected with neurotropic viruses or suffering from experimental allergic encephalitis, we have determined directly the levels of NO present in the central nervous system of such animals. Using spin trapping of NO and electron paramagnetic resonance spectroscopy, we confirm here that copious amounts of NO (up to 30-fold more than control) are elaborated in the brains of rats infected with rabies virus or borna disease virus, as well as in the spinal cords of rats that had received myelin basic protein-specific T cells.
Collapse
Affiliation(s)
- D C Hooper
- Department of Microbiology and Immunology, Jefferson Cancer Institute, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | |
Collapse
|
92
|
Affiliation(s)
- D C Hooper
- Infectious Disease Unit, Massachusetts General Hospital, Boston, USA
| |
Collapse
|
93
|
Dietzschold B, Schwaeble W, Schäfer MK, Hooper DC, Zehng YM, Petry F, Sheng H, Fink T, Loos M, Koprowski H, Weihe E. Expression of C1q, a subcomponent of the rat complement system, is dramatically enhanced in brains of rats with either Borna disease or experimental allergic encephalomyelitis. J Neurol Sci 1995; 130:11-6. [PMID: 7544401 DOI: 10.1016/0022-510x(94)00269-t] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
In situ hybridization, RT-PCR and Northern blot analysis as well immunohistochemistry were used to examine the expression of C1q, a subcomponent of the rat complement system, in brains of rats infected with Borna disease virus (BDV) and rats afflicted with experimental allergic encephalomyelitis (EAE) induced by the adoptive transfer of myelin basic protein specific T cells. C1q mRNA, which was not detected in normal brain, became clearly detectable using RT-PCR analysis by d14 post infection (p.i.) with BDV. Maximal levels of C1q mRNA were reached 21 days p.i. when inflammatory reactions in the brain were also at a peak. Similarly, C1q mRNA was elevated when the clinical symptoms of EAE became evident 5 days following cell transfer. C1q positive cells, as identified by immunohistology, were preferentially localized in grey and white matter of the hippocampus and basolateral cortex. The C1q positive cells resembled microglial cells in morphology. The correlation of C1q expression with the development of neurological disease as well as the dramatic increase of C1q within brain regions with inflammatory lesions suggest that local biosynthesis of C1q may play a role in the pathogenesis of Borna virus induced and autoimmune encephalomyelitis.
Collapse
Affiliation(s)
- B Dietzschold
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107-6799, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
94
|
Affiliation(s)
- D C Hooper
- Infectious Disease Unit, Massachusetts General Hospital, Boston 02114-2696, USA
| |
Collapse
|
95
|
Hooper DC, Molowitz EH, Bos NA, Ploplis VA, Cebra JJ. Spleen cells from antigen-minimized mice are superior to spleen cells from germ-free and conventional mice in the stimulation of primary in vitro proliferative responses to nominal antigens. Eur J Immunol 1995; 25:212-7. [PMID: 7843233 DOI: 10.1002/eji.1830250135] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
T lymphocytes from mice reared under conditions of differential exposure to food, environmental and microbial antigens were compared for phenotypic shifts that may be associated with prior exposure to antigens as well as functional variations in the ability to respond to antigens de novo. While the intra-epithelial CD8 T cell compartment was found to differ significantly in the type of T cell receptor predominantly expressed, CD4 T cells from various lymphoid organs of conventionally reared specific pathogen-free (CL-SPF) mice showed only subtle phenotypic differences from cells obtained from antigen-minimized germ-free (AF) and germ-free (GF) mice. Cells derived from mice exposed to a reduced antigen load exhibited primary in vitro proliferative responses to antigens such as dinitrophenyl-keyhole limpet hemocyanin which were significantly enhanced when compared with similar responses of cells from conventional mice. In cell mixing experiments, differences in the reactivity of T cells from the spleens of AF, GF and CL-SPF mice were dependent on the source of the spleen cells employed as antigen-presenting cells (APC). Experiments in which the T cell population was held constant revealed that, as APC, spleen cells from AF mice were most often superior to spleen cells from GF mice which were in turn considerably better than a similar population from SPF mice. We conclude that the enhanced primary reactivity of spleen cells from AF mice to nominal antigen in vitro is likely to be the result of a difference in the function and/or regulatory activities of the cell population employed as APC in this investigation.
Collapse
Affiliation(s)
- D C Hooper
- Leidy Laboratory of Biology, Department of Biology, University of Pennsylvania, Philadelphia 19104
| | | | | | | | | |
Collapse
|
96
|
Abstract
Physical studies have further defined interactions of quinolones with their principal target, DNA gyrase. The binding of quinolones to the DNA gyrase-DNA complex suggests 2 possible binding sites of differing affinities. Mutations in either the gyrase A gene (gyrA) or the gyrase B gene (gyrB) that affect quinolone susceptibility also affect drug binding, with resistance mutations causing decreased binding and hypersusceptibility mutations causing increased binding. Combinations of mutations in both GyrA and GyrB have further demonstrated the contribution of both subunits to the quinolone sensitivity of intact bacteria and purified DNA gyrase. A working model postulates initial binding of quinolones to proximate sites on GyrA and GyrB. This initial binding then produces conformational changes that expose additional binding sites, possibly involving DNA. Quinolones also inhibit the activities of Escherichia coli topoisomerase IV (encoded by the parC and parE genes), but at concentrations higher than those inhibiting DNA gyrase. The patterns of resistance mutations in gryA and parC suggest that topoisomerase IV may be a secondary drug target in E. coli and Neisseria gonorrhoeae. In contrast, in Staphylococcus aureus these patterns suggest that topoisomerase IV may be a primary target of quinolone action. Regulation of expression of membrane efflux transporters may contribute to quinolone susceptibility in both Gram-positive and Gram-negative bacteria. The substrate profile of the NorA efflux transporter of S. aureus correlates with the extent to which the activity of quinolone substrates is affected by overexpression of NorA. In addition, the Emr transporter of E. coli affects susceptibility to nalidixic acid, and the MexAB OprK transport system of Pseudomonas aeruginosa affects susceptibility to ciprofloxacin.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- D C Hooper
- Infectious Disease Unit, Massachusetts General Hospital, Harvard Medical School, Boston, USA
| |
Collapse
|
97
|
Hooper DC, Pierard I, Modelska A, Otvos L, Fu ZF, Koprowski H, Dietzschold B. Rabies ribonucleocapsid as an oral immunogen and immunological enhancer. Proc Natl Acad Sci U S A 1994; 91:10908-12. [PMID: 7971982 PMCID: PMC45135 DOI: 10.1073/pnas.91.23.10908] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The administration of rabies ribonucleocapsid (RNP) by oral as well as parenteral routes was found to prime specific T cells and elicit N-protein-specific antibodies. per os and intramuscular immunization led to the production of antibodies of the IgA and IgG isotypes, respectively. Mice primed orally with RNP produced significantly enhanced amounts of virus-neutralizing antibody, compared with non-immune controls, upon subsequent parenteral booster immunization with inactivated rabies virus. Thus oral immunization with rabies RNP primed cells capable of mediating a secondary systemic response to rabies virus. The results of experiments in which peptide and protein antigens were administered either physically coupled to or mixed with RNP indicate that RNP has an inherent capacity to enhance immune responses.
Collapse
Affiliation(s)
- D C Hooper
- Department of Microbiology and Immunology, Thomas Jefferson University, Philadelphia, PA 19107-6799
| | | | | | | | | | | | | |
Collapse
|
98
|
Ng EY, Trucksis M, Hooper DC. Quinolone resistance mediated by norA: physiologic characterization and relationship to flqB, a quinolone resistance locus on the Staphylococcus aureus chromosome. Antimicrob Agents Chemother 1994; 38:1345-55. [PMID: 8092836 PMCID: PMC188209 DOI: 10.1128/aac.38.6.1345] [Citation(s) in RCA: 161] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We identified a quinolone resistance locus, flqB, linked to transposon insertion omega 1108 and fus on the SmaI D fragment of the Staphylococcus aureus NCTC 8325 chromosome, the same fragment that contains the norA gene. S. aureus norA cloned from flqB and flqB+ strains in Escherichia coli differed only in a single nucleotide in the putative promoter region. There was no detectable change in the number of copies of norA on the chromosomes of flqB strains, but they had increased levels of norA transcripts. Cloned norA produced resistance to norfloxacin and other hydrophilic quinolones and reduced norfloxacin accumulation in intact cells that was energy dependent, suggesting active drug efflux as the mechanism of resistance. Drug efflux was studied by measurement of norfloxacin uptake into everted inner membrane vesicles prepared from norA-containing E. coli cells. Vesicles exhibited norfloxacin uptake after the addition of lactate or NADH, and this uptake was abolished by carbonyl cyanide m-chlorophenylhydrazone and nigericin but not valinomycin, indicating that it was linked to the pH gradient across the cell membrane. Norfloxacin uptake into vesicles was also saturable, with an apparent Km of 6 microM, a concentration between those that inhibit the growth of flqB and flqB+ S. aureus cells, indicating that drug uptake is mediated by a carrier with a high apparent affinity for norfloxacin. Ciprofloxacin and ofloxacin competitively inhibited norfloxacin uptake into vesicles. Reserpine, which inhibits the multidrug efflux mediated by the bmr gene of bacillus subtilis, which is similar to norA, abolished norfloxacin uptake into vesicles as well as the norfloxacin resistance of an flqB mutant, suggesting a potential means for circumventing quinolone resistance as a result of drug efflux in S. aureus. These findings indicate that the chromosomal flqB resistance locus is associated with increased levels of expression of norA and strongly suggest that the NorA protein itself functions as a drug transporter that is coupled to the proton gradient across the cell membrane.
Collapse
Affiliation(s)
- E Y Ng
- Infectious Disease Unit, Massachusetts General Hospital, Harvard Medical School, Boston 02114-2696
| | | | | |
Collapse
|
99
|
Abstract
Under normal circumstances most lymphoid cell populations do not exhibit strong proliferative reactions in culture unless provoked by antigen or mitogen. The autologous mixed lymphocyte reaction (AMLR) mediated by adult T cells is a relatively weak proliferative response that occurs in the absence of known heterologous stimuli. In this investigation we demonstrate that Peyer's patch (PP) cells possess an inherent capacity to commence dividing in vitro and to display an exceptionally vigorous AMLR. The magnitude and kinetics of this spontaneous proliferation resemble that of a secondary response to a strong mucosal immunogen such as reovirus type 1/Lang. Analysis of the cellular components of the PP cultures implicates CD4+CD8- T cells as the major responding population and dendritic cells (DC) as stimulators. Mixing experiments indicate that spleen contains a cell population which can stimulate PP T cells, albeit to a lesser extent than PP cells. Similarly, splenic T cells have a reduced but significant capacity to respond to PP DC, in comparison to PP T cells. These differences suggest the possibility that there may be a decreasing gradient of antigenicity between the gut and the spleen which is reflected in the spontaneous activity of PP versus splenic T cells in vitro. We propose that PP cells are in fact responding in vitro to heterologous antigens derived from food, enteric microbes and other environmental sources. This notion is supported by the observation that PP cells from antigen-minimized germ-free mice fail to proliferate spontaneously in culture.
Collapse
Affiliation(s)
- D C Hooper
- Leidy Laboratory of Biology, Department of Biology, University of Pennsylvania, Philadelphia 19104-6018
| | | | | |
Collapse
|
100
|
Soussy CJ, Wolfson JS, Ng EY, Hooper DC. Limitations of plasmid complementation test for determination of quinolone resistance due to changes in the gyrase A protein and identification of conditional quinolone resistance locus. Antimicrob Agents Chemother 1993; 37:2588-92. [PMID: 8109921 PMCID: PMC192746 DOI: 10.1128/aac.37.12.2588] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Plasmid pJSW101 derived from pUC19 and carrying the wild-type gyrA gene was found to be unstable in HM72, a quinolone-resistant (QR) clinical isolate of Escherichia coli, and resulted in no change in quinolone MICs. MICs determined in the presence of ampicillin to ensure plasmid presence, however, resulted in complementation. HM72 was proved to have a gyrA mutation based on the DNA sequence of a 418-bp fragment of gyrA. DNA sequencing identified a common mutation encoding Leu-83 as the cause of QR. To identify loci other than gyrA and nfxB contributing to QR in KF111b, zgh-3075::Tn10 (67 min) in CAG12152 was transduced into KF111b. Sixteen percent of the transductants had a fourfold decrease in norfloxacin MIC, indicating the presence of a locus, nfxD, which contributes to QR. Outcross of nfxD from DH151 (gyrA nfxB nfxD zgh-3075::Tn10) resulted in 8% of the KF130 gyrA, 2% of the EN226-3 gyrA, and none of the KL16 (wild-type) transductants, with a four- to eightfold increase in norfloxacin MIC. In the presence of ampicillin, the resistance of a gyrA nfxD double mutant, DH161 nfxD gyrA (from EN226-3), was fully complemented by gyrA+. Thus, gyrA+ plasmid complementation tests for QR may be falsely negative with plasmid instability, a difficulty which may be circumvented by maintenance of plasmid selection. In addition, if nfxD-like mutations occur in gyrA clinical isolates, a positive test may overestimate the level of resistance attributable to gyrA alone.
Collapse
Affiliation(s)
- C J Soussy
- Service de Bactériologie-Virologie-Hygiène, Hôpital Henri Mondor, Université de Paris XII, Créteil, France
| | | | | | | |
Collapse
|