Barbara E. Murray, M.D.
1973, The University of Texas Southwestern Medical School, Dallas
UT-Houston Medical School
Infectious Diseases
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Barbara E. Murray, M.D. 1973, The University of Texas Southwestern Medical School, Dallas UT-Houston Medical School |
Research Interests: Genetics and mechanisms of pathogenicity and of antibiotic resistance in Enterococcus (formerly, Streptococcus) faecalis and E. faecium, important human pathogens
This laboratory's broad interests involve the genetic and biochemical mechanisms of pathogenicity and of resistance to antibiotics, particularly of enterocci (e.g., Enterococcus faecalis and E. faecium). Recent acquisition of new antibiotic resistance traits have led these organisms to be called "super bugs" because of the paucity of any known effective antimicrobials. This laboratory described the first isolate of enterococci producing beta-lactamase and also described the first gentamicin resistance transposon in these organisms, a property which has important consequences for therapy of enterococcal endocarditis. Work in pathogenicity has also focused on enterococci because they are important causes of endocarditis and hospital-acquired infections. Current work, funding by NIH, involves defining the enterococcal antigens which elicit antibody responses in patients infected by these organisms, generating isogenic mutants for studies of virulence and pathogenicity, testing antiserum for protective capabilities, investigating biofilm formation, defining the mechanism of resistance to phagocytosis by white blood cells, and studying potential virulence genes (including collagen and other extracellular matrix adhesin genes, a polysaccharide capsular gene cluster, a gelatinase-serine protease operon regulated by a homolog of a staphylococcal global regulator, and hyaluronidase, among others). Dr. Murray participated in a collaboration with Dr. George Weinstock and the Department of Energy, which resulted in sequencing in a day of a strain of Enterococcus faecium, and is currently collaborating with Dr Weinstock and Dr. Daneille Garsin of microbiology to sequence strains of E. faecalis. Procedures routinely used include genomic sequencing and annotation with Dr. George Weinstock, ELISAs, Western blot analysis, cloning, mutagenesis, microarray analyses and RT-PCR, and other molecular biology techniques, as well as extracellular matrix protein adherence assays, biofilm assays, fluorescent microscopy, transcytosis assays, and animal models (peritonitis and endocarditis). There are active collaborations between the Division of Infectious Diseases, MMG and the Center for Matrix Biology-IBT and shared graduate students with faculty in these areas. Dr. Murray is the Director of the Division of Infectious Diseases and co-director for the Center for the Study of Emerging and Re-Emerging Pathogens. Work in the Center provides a multi-disciplinary approach to the study of bacterial pathogenesis, from clinical issues to details of gene expression and protein function.
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Singh KV, Nallapareddy S, Nannini E, Murray BE (2005).Fsr independent production of protease(s) may explain the lack of attenuation of Enterococcus faecalis fsr mutant versus a gelE-sprE mutant in induction of endocarditis. Infect Immun. (in press).
Aakra A, Vebo H, Snipen L, Hirt, H, Aastveit A, Kapur V, Dunny G, Murray BE, Nes IF (2005). Transcriptional response of Enterococcus faecalis V583 to erythromycin. Antimicrob Agents and Chemother. (in press).
Singh KV and Murray BE (2005). Differences in the Enterococcus faecalis lsa locus that influence susceptibility to quinupristin-dalfopristin and clindamycin. Antimicrob Agents and Chemother 49:32-39.
Kawalec M, Potempa J, Moon JL, Travis J, Murray BE (2005). Molecular diversity of a putative virulence factor: Purification and characterization of isoforms of an extracellular serine glutamyl endopeptidase of Enterococcus faecalis with different enzymatic activities. J Bacteriol 187:266-75.
Teng F, Nannini EC, Murray BE (2005) Importance of Gls24 in virulence and stress response of Enterococcus faecalis and use of the Gls24 protein as a possible immunotherapy target. J Infect Dis 191:472-80.
Zeng J, Teng F, Murray BE (2005) Gelatinase is important for translocation of Enterococcus faecalis across polarized human enterocyte-like T84 cells. Infect Immun 73:1606-12.
Sillanpaa J, Xu Y, Nallapareddy S, Murray BE, Hook M (2004). A family of putative MSCRAMMs from Enterococcus faecalis. Microbiol 150:2069-78.
Mohamed J, Huang W, Nallapareddy S, Teng F, Murray BE (2004). Influence of clinical origin, especially endocarditis, and of various genes on biofilm formation by Enterococcus faecalis. Infect Immun 71:1301-1303.
Zeng J, Teng F, Weinstock G, Murray BE (2004). Translocation of Enterrococcus faecalis strains across a monolayer of polarized human enterocyte-like T84 cells. J Clin Microbiol 42:1149-1154.
Nallapareddy SR, Weinstock GM, Murray BE (2003). Clinical isolates of Enterococcus faecium exhibit strain-specific collagen binding mediated by Acm, a new member of the MSCRAMM family. Mol Microbiol. Mar;47(6):1733-47.
Rice LB, Carias L, Rudin S, Vael C, Goossens H, Konstabel C, Klare I, Nallapareddy SR, Huang W, Murray BE (2003). A potential virulence gene, hylEfm, predominates in Enterococcus faecium of clinical origin. J Infect Dis. Feb 1;187(3):508-12.
Singh KV, Weinstock GM, Murray BE (2002). An Enterococcus faecalis ABC homologue (Lsa) is required for the resistance of this species to clindamycin and quinupristin-dalfopristin. Antimicrob Agents Chemother. Jun;46(6):1845-50.
Teng F, Jacques-Palaz KD, Weinstock GM, Murray BE (2002). Evidence that the enterococcal polysaccharide antigen gene (epa) cluster is widespread in Enterococcus faecalis and influences resistance to phagocytic killing of E. faecalis. Infect Immun. Apr;70(4):2010-5.
Teng F, Wang L, Singh KV, Murray BE, Weinstock GM (2002). Involvement of PhoP-PhoS homologs in Enterococcus faecalis virulence. Infect Immun. Apr;70(4):1991-6.
Nallapareddy SR, Duh RW, Singh KV, Murray BE (2002). Molecular typing of selected Enterococcus faecalis isolates: pilot study using multilocus sequence typing and pulsed-field gel electrophoresis. J Clin Microbiol. Mar;40(3):868-76.
Singh KV, Malathum K, Murray BE (2001). Disruption of an Enterococcus faecium species-specific gene, a homologue of acquired macrolide resistance genes of Staphylococci, is associated with an increase in macrolide susceptibility. Antimicrob Agents Chemother 45:263-266.
Qin X, Singh KV, Weinstock GM, Murray BE (2001). Characterization of fsr, a regulator controlling expression of gelatinase and serine protease in Enterococcus faecalis OG1RF. J Bacteriol. Jun;183(11):3372-82.
Nallapareddy SR, Qin X, Weinstock GM, Hook M, Murray BE (2000). Enterococcus faecalis adhesin, ace, mediates attachment to extracellular matrix proteins collagen type IV and laminin as well as collagen type I.
Infect Immun. Sep;68(9):5218-24.
Rakita RM, Quan VC, Jacques-Palaz K, Singh KV, Arduino RC, Mee M, Murray BE (2000). Specific antibody promotes opsonization and PMN-mediated killing of phagocytosis-resistant Enterococcus faecium. FEMS Immunol Med Microbiol. Aug;28(4):291-9.
Qin X, Singh KV, Weinstock GM, Murray BE (2000). Effects of Enterococcus faecalis fsr genes on production of gelatinase and a serine protease and virulence. Infect Immun. May;68(5):2579-86.
Nallapareddy SR, Singh KV, Duh RW, Weinstock GM, Murray BE (2000). Diversity of ace, a gene encoding a microbial surface component recognizing adhesive matrix molecules, from different strains of Enterococcus faecalis and evidence for production of ace during human infections. Infect Immun 68:5210-5217.
Nallapareddy SR, Qin X, Weinstock GM, Hook M, Murray BE (2000). Enterococcus faecalis adhesin, ace, mediates attachment to extracellular matrix proteins collagen type IV and laminin as well as collagen type I. Infect Immun 68:5218-5224.
Qin X, Singh KV, Weinstock GM, Murray BE (2000). Effects of Enterococcus faecalis fsr genes on production of gelatinase and a serine protease and virulence. Infect Immun 68:2579-2586.
Murray BE (2000). Vancomycin-resistant enterococcal infections. New Engl J Med 342:710-721.
Xu Y, Singh KV, Qin X, Murray BE (2000). Analysis of a gene cluster of Enterococcus faecalis involved in polysaccharide biosyntheses. Infect Immun 68:815-823.
Rich RL, Kreikemeyer B, Owens RT, LaBrenz S, Narayama SVL, Weinstock GM, Murray BE, Hook M (1999). Ace is a collagen-binding MSCRAMM from Enterococcus faecalis. J Biol Chem 274:26939-26945.
Coque TM, Singh KV, Weinstock GM, Murray BE (1999). Characterization of dihydrofolate reductase genes from trimethoprim susceptible and trimethoprim resistant strains of Enterococcus faecalis. Antimicrob Agents Chemother 43:141-147.
Singh KV, Qin X, Weinstock GM, Murray BE (1998). Generation and testing of mutants of Enterococcus faecalis in a mouse peritonitis model. J Infect Dis 178:1416-1420.
Xiao J, Hook M, Weinstock GM, Murray BE (1998). Conditional adherence of Enterococcus faecalis to extracellular matrix proteins. FEMS Immun Med Microbiol 21:287-295.
Teng F, Murray BE, Weinstock GM (1998). Conjugal transfer of plasmid DNA from Escherichia coli to enterocicci: a method to make insertion mutations. Plasmid 39:182-186.
Program Affiliation:
Program in Microbiology and Molecular Genetics