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Hunfeld KP, Kraiczy P, Norris DE, Lohr B. The In Vitro Antimicrobial Susceptibility of Borrelia burgdorferi sensu lato: Shedding Light on the Known Unknowns. Pathogens 2023; 12:1204. [PMID: 37887720 PMCID: PMC10609913 DOI: 10.3390/pathogens12101204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/08/2023] [Accepted: 09/12/2023] [Indexed: 10/28/2023] Open
Abstract
Human Lyme borreliosis (LB) represents a multisystem disorder that can progress in stages. The causative agents are transmitted by hard ticks of the Ixodes ricinus complex that have been infected with the spirochete Borrelia burgdorferi sensu lato. Today, LB is considered the most important human tick-borne illness in the Northern Hemisphere. The causative agent was identified and successfully isolated in 1982 and, shortly thereafter, antibiotic treatment was found to be safe and efficacious. Since then, various in vitro studies have been conducted in order to improve our knowledge of the activity of antimicrobial agents against B. burgdorferi s. l. The full spectrum of in vitro antibiotic susceptibility has still not been defined for some of the more recently developed compounds. Moreover, our current understanding of the in vitro interactions between B. burgdorferi s. l. and antimicrobial agents, and their possible mechanisms of resistance remains very limited and is largely based on in vitro susceptibility experiments on only a few isolates of Borrelia. Even less is known about the possible mechanisms of the in vitro persistence of spirochetes exposed to antimicrobial agents in the presence of human and animal cell lines. Only a relatively small number of laboratory studies and cell culture experiments have been conducted. This review summarizes what is and what is not known about the in vitro susceptibility of B. burgdorferi s. l. It aims to shed light on the known unknowns that continue to fuel current debates on possible treatment resistance and mechanisms of persistence of Lyme disease spirochetes in the presence of antimicrobial agents.
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Affiliation(s)
- Klaus-Peter Hunfeld
- Institute for Laboratory Medicine, Microbiology & Infection Control, Northwest Medical Centre, Academic Teaching Hospital, Medical Faculty, Goethe University Frankfurt, Steinbacher Hohl 2-26, D-60488 Frankfurt am Main, Germany;
- INSTAND e.V., Gesellschaft zur Förderung der Qualitätssicherung in medizinischen Laboratorien e.V., Ubierstraße 20, D-40223 Düsseldorf, Germany
| | - Peter Kraiczy
- Institute for Medical Microbiology & Infection Control, University Hospital Frankfurt, Goethe University Frankfurt, Paul-Ehrlich Str. 40, D-60596 Frankfurt am Main, Germany;
| | - Douglas E. Norris
- W. Harry Feinstone Department of Molecular Microbiology & Immunology, Bloomberg School of Public Health, Johns Hopkins University, 615 N Wolfe St, Baltimore, MD 21205, USA;
| | - Benedikt Lohr
- Institute for Laboratory Medicine, Microbiology & Infection Control, Northwest Medical Centre, Academic Teaching Hospital, Medical Faculty, Goethe University Frankfurt, Steinbacher Hohl 2-26, D-60488 Frankfurt am Main, Germany;
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2
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Franco J, Scarone L, Comini MA. Novel distamycin analogues that block the cell cycle of African trypanosomes with high selectivity and potency. Eur J Med Chem 2020; 189:112043. [PMID: 31978782 DOI: 10.1016/j.ejmech.2020.112043] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/03/2019] [Accepted: 01/06/2020] [Indexed: 02/07/2023]
Abstract
Polyamides-based compounds related to the Streptomycetal distamycin and netropsin are potent cytostatic molecules that bind to AT-rich regions of the minor groove of the DNA, hence interfering with DNA replication and transcription. Recently, derivatives belonging to this scaffold have been reported to halt the proliferation of deadly African trypanosomes by different and unrelated mechanisms. Here we describe the synthesis and preliminary characterization of the anti-trypanosomal mode of action of new potent and selective distamycin analogues. Two tri-heterocyclic derivatives containing a central N-methyl pyrrole ring (16 and 17) displayed high activity (EC50 < 20 nM) and selectivity (selectivity index >5000 with respect to mammalian macrophages) against the infective form of T. brucei. Both compounds caused cell cycle arrest by blocking the replication of the mitochondrial DNA but without affecting its integrity. This mode of action clearly differs from that reported for classical minor groove binder (MGB) drugs, which induce the degradation of the mitochondrial DNA. In line with this, in vitro assays suggest that 16 and 17 have a comparatively lower affinity for different template DNAs than the MGB drug diminazene. Therapeutic efficacy studies and stability assays suggest that the pharmacological properties of the hits should be optimized. The compounds can be rated as excellent scaffolds for the design of highly potent and selective anti-T. brucei agents.
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Affiliation(s)
- Jaime Franco
- Laboratorio de Química Farmacéutica, Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay; Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Laura Scarone
- Laboratorio de Química Farmacéutica, Departamento de Química Orgánica, Facultad de Química, Universidad de la República, Montevideo, Uruguay.
| | - Marcelo A Comini
- Group Redox Biology of Trypanosomes, Institut Pasteur de Montevideo, Montevideo, Uruguay.
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3
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Biodegradation of antibiotics: The new resistance determinants – part I. N Biotechnol 2020; 54:34-51. [DOI: 10.1016/j.nbt.2019.08.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 07/17/2019] [Accepted: 08/06/2019] [Indexed: 12/07/2022]
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4
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Abstract
The spirochetes Borrelia (Borreliella) burgdorferi and Borrelia hermsii, the etiologic agents of Lyme disease and relapsing fever, respectively, cycle in nature between an arthropod vector and a vertebrate host. They have extraordinarily unusual genomes that are highly segmented and predominantly linear. The genetic analyses of Lyme disease spirochetes have become increasingly more sophisticated, while the age of genetic investigation in the relapsing fever spirochetes is just dawning. Molecular tools available for B. burgdorferi and related species range from simple selectable markers and gene reporters to state-of-the-art inducible gene expression systems that function in the animal model and high-throughput mutagenesis methodologies, despite nearly overwhelming experimental obstacles. This armamentarium has empowered borreliologists to build a formidable genetic understanding of the cellular physiology of the spirochete and the molecular pathogenesis of Lyme disease.
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Affiliation(s)
- Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.
| | - D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, 59812, USA.
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5
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Kim SH, Kang PA, Han K, Lee SW, Rhee S. Crystal structure of chloramphenicol-metabolizing enzyme EstDL136 from a metagenome. PLoS One 2019; 14:e0210298. [PMID: 30645605 PMCID: PMC6333409 DOI: 10.1371/journal.pone.0210298] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 12/18/2018] [Indexed: 01/07/2023] Open
Abstract
Metagenomes often convey novel biological activities and therefore have gained considerable attention for use in biotechnological applications. Recently, metagenome-derived EstDL136 was found to possess chloramphenicol (Cm)-metabolizing features. Sequence analysis showed EstDL136 to be a member of the hormone-sensitive lipase (HSL) family with an Asp-His-Ser catalytic triad and a notable substrate specificity. In this study, we determined the crystal structures of EstDL136 and in a complex with Cm. Consistent with the high sequence similarity, the structure of EstDL136 is homologous to that of the HSL family. The active site of EstDL136 is a relatively shallow pocket that could accommodate Cm as a substrate as opposed to the long acyl chain substrates typical of the HSL family. Mutational analyses further suggested that several residues in the vicinity of the active site play roles in the Cm-binding of EstDL136. These results provide structural and functional insights into a metagenome-derived EstDL136.
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Affiliation(s)
- Sang-Hoon Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Pyeoung-Ann Kang
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Keetae Han
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Seon-Woo Lee
- Department of Applied Biology, Dong-A University, Busan, Korea
- * E-mail: (SR); (SWL)
| | - Sangkee Rhee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
- * E-mail: (SR); (SWL)
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6
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Nasrin S, Ganji S, Kakirde KS, Jacob MR, Wang M, Ravu RR, Cobine PA, Khan IA, Wu CC, Mead DA, Li XC, Liles MR. Chloramphenicol Derivatives with Antibacterial Activity Identified by Functional Metagenomics. JOURNAL OF NATURAL PRODUCTS 2018; 81:1321-1332. [PMID: 29897754 DOI: 10.1021/acs.jnatprod.7b00903] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A functional metagenomic approach identified novel and diverse soil-derived DNAs encoding inhibitors to methicillin-resistant Staphylococcus aureus (MRSA). A metagenomic DNA soil library containing 19 200 recombinant Escherichia coli BAC clones with 100 Kb average insert size was screened for antibiotic activity. Twenty-seven clones inhibited MRSA, seven of which were found by LC-MS to possess modified chloramphenicol ( Cm) derivatives, including three new compounds whose structures were established as 1-acetyl-3-propanoylchloramphenicol, 1-acetyl-3-butanoylchloramphenicol, and 3-butanoyl-1-propanoylchloramphenicol. Cm was used as the selectable antibiotic for cloning, suggesting that heterologously expressed enzymes resulted in derivatization of Cm into new chemical entities with biological activity. An esterase was found to be responsible for the enzymatic regeneration of Cm, and the gene trfA responsible for plasmid copy induction was found to be responsible for inducing antibacterial activity in some clones. Six additional acylchloramphenicols were synthesized for structure and antibacterial activity relationship studies, with 1- p-nitrobenzoylchloramphenicol the most active against Mycobacterium intracellulare and Mycobacterium tuberculosis, with MICs of 12.5 and 50.0 μg/mL, respectively.
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Affiliation(s)
- Shamima Nasrin
- Department of Biological Sciences , Auburn University , Auburn , Alabama 36849 , United States
| | - Suresh Ganji
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Kavita S Kakirde
- Department of Biological Sciences , Auburn University , Auburn , Alabama 36849 , United States
| | - Melissa R Jacob
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Mei Wang
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Ranga Rao Ravu
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Paul A Cobine
- Department of Biological Sciences , Auburn University , Auburn , Alabama 36849 , United States
| | - Ikhlas A Khan
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
- Department of Biomolecular Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Cheng-Cang Wu
- Lucigen Corporation , Middleton , Wisconsin 53562 , United States
| | - David A Mead
- Varigen Biosciences Corporation , Madison , Wisconsin 53719 , United States
| | - Xing-Cong Li
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
- Department of Biomolecular Sciences, School of Pharmacy , The University of Mississippi , University , Mississippi 38677 , United States
| | - Mark R Liles
- Department of Biological Sciences , Auburn University , Auburn , Alabama 36849 , United States
- Varigen Biosciences Corporation , Madison , Wisconsin 53719 , United States
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7
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Abstract
The disciplines of Borrelia (Borreliella) burgdorferi microbiology and Lyme disease pathogenesis have come to depend on the genetic manipulation of the spirochete. Generating mutants in these recalcitrant bacteria, while not straightforward, is routinely accomplished in numerous laboratories, although there are several crucial caveats to consider. This chapter describes the design of basic molecular genetic experiments as well as the detailed methodologies to prepare and transform competent cells, select for and isolate transformants, and complement or genetically restore mutants.
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Affiliation(s)
- D Scott Samuels
- Division of Biological Sciences, University of Montana, Missoula, MT, USA.
| | - Dan Drecktrah
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | - Laura S Hall
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
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8
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Vibholm L, Reinert LS, Søgaard OS, Paludan SR, Østergaard L, Tolstrup M, Melchjorsen J. Antiviral and immunological effects of tenofovir microbicide in vaginal herpes simplex virus 2 infection. AIDS Res Hum Retroviruses 2012; 28:1404-11. [PMID: 22867119 DOI: 10.1089/aid.2012.0078] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The anti-HIV microbicide, tenofovir (TFV) gel, has been shown to decrease HIV-1 acquisition by 39% and reduce herpes simplex virus 2 (HSV-2) transmission by 51%. We evaluated the effect of a 1% TFV gel on genital HSV-2 infection in a mouse vaginal challenge model. In vitro plaque assays and luminex multiplex bead analysis were used, respectively, to measure postinfection vaginal viral shedding (day 1) and cytokine secretion (day 2). To further investigate the anti-HSV-2 properties, we evaluated the direct antiviral effect of TFV and the oral prodrug tenofovir disoproxil fumerate (TDF) in cell culture. Compared to placebo-treated mice, TFV-treated mice had significantly lower clinical scores, developed later genital lesions, and showed reduced vaginal viral shedding. Furthermore, the levels of IFN-γ, IL-2, TNF-α, and other cytokines were altered in the vaginal fluid following topical tenofovir treatment and subsequent HSV-2 challenge. Finally, we found that both TFV and TDF inhibited HSV-2 infection in vitro; TDF showed a 50-fold greater potency than TFV. In conclusion, we confirmed that the microbicide TFV had direct anti-HSV-2 effects in a murine vaginal challenge model. Therefore, this model would be suitable for evaluating present and future microbicide candidates. Furthermore, the present study warrants further investigation of TDF in microbicides.
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Affiliation(s)
- Line Vibholm
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Line S. Reinert
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Ole S. Søgaard
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | | | - Lars Østergaard
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Martin Tolstrup
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
| | - Jesper Melchjorsen
- Department of Infectious Diseases, Aarhus University Hospital, Aarhus, Denmark
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9
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Sambir M, Ivanova LB, Bryksin AV, Godfrey HP, Cabello FC. Functional analysis of Borrelia burgdorferi uvrA in DNA damage protection. FEMS Microbiol Lett 2011; 317:172-80. [PMID: 21272060 DOI: 10.1111/j.1574-6968.2011.02226.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Bacterial pathogens face constant challenges from DNA-damaging agents generated by host phagocytes. Although Borrelia burgdorferi appears to have much fewer DNA repair enzymes than pathogens with larger genomes, it does contain homologues of uvrA and uvrB (subunits A and B of excinuclease ABC). As a first step to exploring the physiologic function of uvrA(Bbu) and its possible role in survival in the host in the face of DNA-damaging agents, a partially deleted uvrA mutant was isolated by targeted inactivation. While growth of this mutant was markedly inhibited by UV irradiation, mitomycin C (MMC) and hydrogen peroxide at doses that lacked effect on wild-type B. burgdorferi, its response to pH 6.0-6.8 and reactive nitrogen intermediates was similar to that of the wild-type parental strain. The sensitivity of the inactivation mutant to UV irradiation, MMC and peroxide was complemented by an extrachromosomal copy of uvrA(Bbu). We conclude that uvrA(Bbu) is functional in B. burgdorferi.
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Affiliation(s)
- Mariya Sambir
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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10
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Rödel R, Freyer A, Bittner T, Schäfer V, Hunfeld KP. In vitro activities of faropenem, ertapenem, imipenem and meropenem against Borrelia burgdorferi s.l. Int J Antimicrob Agents 2007; 30:83-6. [PMID: 17512703 DOI: 10.1016/j.ijantimicag.2007.03.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Revised: 03/13/2007] [Accepted: 03/14/2007] [Indexed: 11/28/2022]
Abstract
Little is known about the in vitro activity of penems and carbapenems against the spirochete Borrelia burgdorferi. Here, faropenem, ertapenem, imipenem and meropenem as well as the third-generation cephalosporin ceftriaxone and tobramycin were tested in vitro against 11 isolates of the B. burgdorferi sensu lato complex. On a microg/mL basis, ertapenem was the most potent carbapenem (minimal inhibitory concentration (MIC) range: 0.015-0.125 microg/mL), with in vitro activity comparable with that of ceftriaxone against Borrelia. These findings are supported by the results of time-kill experiments in a Borrelia afzelii skin isolate, demonstrating a >3 log10 unit (99.9%) reduction of the inoculum after 96 h of exposure to either drug at a concentration of three log2 unit dilutions above the respective MIC.
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Affiliation(s)
- Rebecca Rödel
- Institute of Medical Microbiology & Infection Control, University Hospital of Frankfurt, Paul-Ehrlich Str. 40, D-60596 Frankfurt/Main, Germany
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11
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Hunfeld KP, Brade V. Antimicrobial susceptibility of Borrelia burgdorferi sensu lato: what we know, what we don't know, and what we need to know. Wien Klin Wochenschr 2007; 118:659-68. [PMID: 17160604 DOI: 10.1007/s00508-006-0693-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Human Lyme borreliosis is a multisystem disorder that can progress in stages and is transmitted by ticks of the Ixodes ricinus complex infected with the spirochete Borrelia burgdorferi sensu lato. Today, Lyme borreliosis is regarded as the most important human tickborne illness in the northern hemisphere. Soon after the causative agent was correctly identified and successfully isolated in 1982, antibiotic treatment was shown to be effective and since then a variety of in vitro and in vivo studies have been performed to further characterize the activity of antimicrobial agents against B. burgdorferi s.l. Although many antimicrobial agents have been tested for their in vitro activity against borreliae, the full spectrum of antibiotic susceptibility in B. burgdorferi s.l. has not been defined for many compounds. Moreover, our current understanding of possible antimicrobial resistance mechanisms in B. burgdorferi s.l. is limited and is largely founded on in vitro experiments on relatively few borrelial isolates. This review will summarize what is and what is not known about antimicrobial resistance in B. burgdorferi s.l. and will discuss open questions that continue to fuel the current debate on treatment-resistant Lyme borreliosis.
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Affiliation(s)
- Klaus-Peter Hunfeld
- Institute of Medical Microbiology and Infection Control, University Hospital of Frankfurt, Frankfurt/Main, Germany.
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12
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Cluss RG, Silverman DA, Stafford TR. Extracellular secretion of the Borrelia burgdorferi Oms28 porin and Bgp, a glycosaminoglycan binding protein. Infect Immun 2004; 72:6279-86. [PMID: 15501754 PMCID: PMC523065 DOI: 10.1128/iai.72.11.6279-6286.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Borrelia burgdorferi, the Lyme disease pathogen, cycles between its Ixodes tick vector and vertebrate hosts, adapting to vastly different biochemical environments. Spirochete gene expression as a function of temperature, pH, growth phase, and host milieu is well studied, and recent work suggests that regulatory networks are involved. Here, we examine the release of Borrelia burgdorferi strain B31 proteins into conditioned medium. Spirochetes intrinsically radiolabeled at concentrations ranging from 10(7) to 10(9) cells per ml secreted Oms28, a previously characterized outer membrane porin, into RPMI medium. As determined by immunoblotting, this secretion was not associated with outer membrane blebs or cytoplasmic contamination. A similar profile of secreted proteins was obtained for spirochetes radiolabeled in mixtures of RPMI medium and serum-free Barbour-Stoenner-Kelly (BSK II) medium. Proteomic liquid chromatography-tandem mass spectrometry analysis of tryptic fragments derived from strain B31 culture supernatants confirmed the identity of the 28-kDa species as Oms28 and revealed a 26-kDa protein as 5'-methylthioadenosine/S-adenosylhomocysteine nucleosidase (Pfs-2), previously described as Bgp, a glycosaminoglycan-binding protein. The release of Oms28 into the culture medium is more selective when the spirochetes are in logarithmic phase of growth compared to organisms obtained from stationary phase. As determined by immunoblotting, stationary-phase spirochetes released OspA, OspB, and flagellin. Oms28 secreted by strains B31, HB19, and N40 was also recovered by radioimmunoprecipitation. This is the first report of B. burgdorferi protein secretion into the extracellular environment. The possible roles of Oms28 and Bgp in the host-pathogen interaction are considered.
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Affiliation(s)
- Robert G Cluss
- Department of Chemistry and Biochemistry, Middlebury College, VT 05753, USA.
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13
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Sohaskey CD. Enzymatic inactivation and reactivation of chloramphenicol byMycobacterium tuberculosisandMycobacterium bovis. FEMS Microbiol Lett 2004; 240:187-92. [PMID: 15522506 DOI: 10.1016/j.femsle.2004.09.028] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2004] [Revised: 09/01/2004] [Accepted: 09/22/2004] [Indexed: 11/25/2022] Open
Abstract
Mycobacterium tuberculosis and Mycobacterium bovis are inhibited by chloramphenicol. Chloramphenicol acetyltransferase (CAT) converts chloramphenicol to inactive diacetyl chloramphenicol, but a mycobacterial carboxylesterase hydrolyzes the diacetyl product to active chloramphenicol. The esterase activity was eliminated by proteinase K and heat treatment. Protein extracts of M. tuberculosis and M. bovis hydrolyzed four other ester substrates. cat was inserted into the chromosome of both M. tuberculosis and M. bovis resulting in a level of chloramphenicol resistance that could be used to select for transformants. CAT assays in the resistant strain of M. tuberculosis showed interference due to esterase activity. This interference could be eliminated with the addition of a heating step.
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Affiliation(s)
- Charles D Sohaskey
- Department of Veterans Affairs Medical Center, Tuberculosis Research Laboratory, 5901 East Seventh Street, Long Beach, CA 90822, USA.
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14
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Hunfeld KP, Wichelhaus TA, Rödel R, Acker G, Brade V, Kraiczy P. Comparison of in vitro activities of ketolides, macrolides, and an azalide against the spirochete Borrelia burgdorferi. Antimicrob Agents Chemother 2004; 48:344-7. [PMID: 14693564 PMCID: PMC310164 DOI: 10.1128/aac.48.1.344-347.2004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two ketolides, three macrolides, and one azalide were tested in vitro against 17 isolates of the B. burgdorferi s.l. complex. As measured in micrograms per milliliter, activity was highest for cethromycin (MIC at which 90% of the tested isolates were inhibited [MIC(90)], 0.0019 micro g/ml) and telithromycin (MIC(90), 0.0078 micro g/ml). Electron-microscope analysis and time-kill studies also supported enhanced effectiveness of both ketolides.
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Affiliation(s)
- Klaus-Peter Hunfeld
- Institute of Medical Microbiology, University Hospital of Frankfurt, D-60596 Frankfurt/Main, Germany.
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15
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Hunfeld KP, Kraiczy P, Kekoukh E, Schäfer V, Brade V. Standardised in vitro susceptibility testing of Borrelia burgdorferi against well-known and newly developed antimicrobial agents--possible implications for new therapeutic approaches to Lyme disease. Int J Med Microbiol 2002; 291 Suppl 33:125-37. [PMID: 12141737 DOI: 10.1016/s1438-4221(02)80024-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Lyme disease represents a disorder of potentially chronic proportions, and relatively little is known about the in vivo pharmacodynamic interactions of antimicrobial agents with borreliae. So far, evidence-based drug regimens for the effective treatment of Lyme disease have not been definitively established. Moreover, therapeutic failures have been reported for almost every suitable antimicrobial agent currently available. Resistance to treatment and a protracted course of the disease, therefore, continue to pose problems for clinicians in the management of patients suffering from chronic Lyme disease. Further characterisation of the antibiotic susceptibility pattern and a better understanding of the interactions of B. burgdorferi with antimicrobial agents are urgently needed and continue to be crucial owing to considerable differences in the experimental conditions and test methods applied. The development of easily performed, new techniques for the sensitivity testing of B. burgdorferi provides the opportunity to study factors affecting the bacteriostatic and bactericidal action of recently introduced chemotherapeutic agents under more standardised conditions. For the first time, these studies provide direct evidence that, in addition to beta-lactams, macrolides, and tetracyclines which are recommended for stage-dependent treatment of Lyme borreliosis, other recently introduced substances, such as fluoroquinolones, everninomycins, and the ketolide family of antimicrobial agents, also show enhanced in vitro activity against borreliae. Some of these compounds, if effective in vivo as well, may prove to be useful agents in the treatment of certain manifestations of Lyme disease. As such, their potential role should be evaluated further by in vivo experiments and clinical trials. Finally, these antimicrobial agents may turn out to be very effective therapeutic alternatives on account of their oral availability, favourable pharmacodynamic profiles, and high tissue levels in cases where beta-lactames or tetracyclines cannot be administered without detrimental side-effects.
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Affiliation(s)
- Klaus-Peter Hunfeld
- Institute of Medical Microbiology, University Hospital of Frankfurt, Germany.
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16
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Bono JL, Elias AF, Kupko JJ, Stevenson B, Tilly K, Rosa P. Efficient targeted mutagenesis in Borrelia burgdorferi. J Bacteriol 2000; 182:2445-52. [PMID: 10762244 PMCID: PMC111306 DOI: 10.1128/jb.182.9.2445-2452.2000] [Citation(s) in RCA: 183] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Genetic studies in Borrelia burgdorferi have been hindered by the lack of a nonborrelial selectable marker. Currently, the only selectable marker is gyrB(r), a mutated form of the chromosomal gyrB gene that encodes the B subunit of DNA gyrase and confers resistance to the antibiotic coumermycin A(1). The utility of the coumermycin-resistant gyrB(r) gene for targeted gene disruption is limited by a high frequency of recombination with the endogenous gyrB gene. A kanamycin resistance gene (kan) was introduced into B. burgdorferi, and its use as a selectable marker was explored in an effort to improve the genetic manipulation of this pathogen. B. burgdorferi transformants with the kan gene expressed from its native promoter were susceptible to kanamycin. In striking contrast, transformants with the kan gene expressed from either the B. burgdorferi flaB or flgB promoter were resistant to high levels of kanamycin. The kanamycin resistance marker allows efficient direct selection of mutants in B. burgdorferi and hence is a significant improvement in the ability to construct isogenic mutant strains in this pathogen.
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Affiliation(s)
- J L Bono
- Laboratory of Human Bacterial Pathogenesis, National Institute of Allergy and Infectious Disease, National Institutes of Health, Hamilton, Montana 59840, USA.
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Sartakova M, Dobrikova E, Cabello FC. Development of an extrachromosomal cloning vector system for use in Borrelia burgdorferi. Proc Natl Acad Sci U S A 2000; 97:4850-5. [PMID: 10781091 PMCID: PMC18321 DOI: 10.1073/pnas.080068797] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Molecular genetic analysis of Borrelia burgdorferi, the cause of Lyme disease, has been hampered by the absence of any means of efficient generation, identification, and complementation of chromosomal and plasmid null gene mutants. The similarity of borrelial G + C content to that of Gram-positive organisms suggested that a wide-host-range plasmid active in Gram-positive bacteria might also be recognized by borrelial DNA replication machinery. One such plasmid, pGK12, is able to propagate in both Gram-positive and Gram-negative bacteria and carries erythromycin and chloramphenicol resistance markers. pGK12 propagated extrachromosomally in B. burgdorferi B31 after electroporation but conferred only erythromycin resistance. pGK12 was used to express enhanced green fluorescent protein in B31 under the control of the flaB promoter. Escherichia coli transformed with pGK12 DNA extracted from B31 expressing only erythromycin resistance developed both erythromycin and chloramphenicol resistance, and plasmid DNA isolated from these transformed E. coli had a restriction pattern similar to the original pGK12. Our data indicate that the replicons of pGK12 can provide the basis to continue developing efficient genetic systems for B. burgdorferi together with the erythromycin resistance and reporter egfp genes.
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Affiliation(s)
- M Sartakova
- Department of Microbiology and Immunology, New York Medical College, Valhalla, NY 10595, USA
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Abstract
The free-living spirochete Spirochaeta aurantia was nearly as susceptible to diacetyl chloramphenicol, the product of chloramphenicol acetyltransferase, as it was to chloramphenicol itself. This unexpected susceptibility to diacetyl chloramphenicol was wholly or partly the consequence of intrinsic carboxylesterase activity, as indicated by high-performance liquid chromatography, thin-layer chromatography, and microbiological assays. The esterase converted the diacetate to chloramphenicol, thus inhibiting spirochete growth. The esterase activity was cell associated, reduced by proteinase K, eliminated by boiling, and independent of the presence of either chloramphenicol or diacetyl chloramphenicol. S. aurantia extracts also hydrolyzed other esterase substrates, and two of these, alpha-napthyl acetate and 4-methylumbelliferyl acetate, identified an esterase of approximately 75 kDa in a nondenaturing gel. Carboxylesterases occur in Streptomyces species, but in this study their activity was weaker than that of S. aurantia. The S. aurantia esterase could reduce the effectiveness of cat as either a selectable marker or a reporter gene in this species.
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Affiliation(s)
- C D Sohaskey
- Departments of Microbiology and Molecular Genetics and Medicine, University of California, Irvine, Irvine, California 92697, USA
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Sohaskey CD, Zückert WR, Barbour AG. The extended promoters for two outer membrane lipoprotein genes of Borrelia spp. uniquely include a T-rich region. Mol Microbiol 1999; 33:41-51. [PMID: 10411722 DOI: 10.1046/j.1365-2958.1999.01443.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OspA and B proteins of Borrelia burgdorferi and Vmp proteins of Borrelia hermsii are abundant outer membrane lipoproteins, whose expression varies with the environment. The genes for these proteins have the '-35' and '-10' elements of a sigma70-type promoter. Deletions of the promoters for these genes were analysed with a chloramphenicol acetyltransferase (CAT) reporter gene and plasmid constructs that were stably maintained in Escherichia coli or transiently transfected into B. burgdorferi. Reporter expression was measured as susceptibility of transformed E. coli cells to chloramphenicol and the CAT activity of E. coli and B. burgdorferi lysates in vitro. Presence of the '-10' element was essential for full activity in both B. burgdorferi and E. coli. Upstream of the '-35' elements of the ospAB and vmp promoters were tracts with Ts in 16 of 20 positions for B. burgdorferi and 18 of 20 positions for B. hermsii. Deletion of the T-rich region from the ospAB or vmp promoter caused a greater reduction of CAT activity in B. burgdorferi than in E. coli. The findings indicate that ospAB and vmp promoters are extended promoters with two parts: (i) a core region containing typical '-35' and '-10' elements and (ii) a unique T-rich region.
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Affiliation(s)
- C D Sohaskey
- Departments of Microbiology and Molecular Genetics and Medicine, B240 Med Sci I, University of California Irvine, Irvine, CA 92697 4025, USA
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