Candidatus neoehrlichia mikurensis- löytyi göteborgilaiselta 2009.

27.10.2011 - New tick-borne disease 

Saksalainen selvitys  tämän bakteerin löydöstä: 

Schwedische Forscher haben eine neue, von Zecken übertragene, Krankheit entdeckt, welche in den Lungen und in den Beinen Blutverklumpungen erzeugen kann. Insgesamt hat es in Europa schon 8 Infektionsfälle gegeben mit 3 Fällen in Schweden, weitere Fälle sind in Deutschland, in der Schweiz und in Tschechien beobachtet worden. Alle betroffenen Personen leiden an einem geschwächten Immunsystem. Die Krankheit, welche die Forscher als „neo Krankheit“, nach dem Namen des Bakteriums (Candidatus Neoehrlichia mikurensis) benannt haben, bewirkt auch Grippe-ähnliche Symptome mit langanhaltendem, hohem Fieber, Hustenkurensis  und Schmerzen, sie kann aber mit Antibiotika bekämpft werden. Der 1. Fall wurde 2009 bei einem 77-jährigen Mann aus Gothenburg entdeckt, der hohes Fieber hatte und dass das Bewusstsein verlor. Während seiner Behandlung entdeckten die Ärzte in seiner Lunge und in den Beinen Blutverklumpungen. Das Fieber des Mannes kam einige Male wieder zurück und dann fanden die Ärzte Spuren eines unbekannten Bakteriums in seinem Blut. Die Krankheit wird von Zecken übertragen und war zuvor in Schweden nie aufgetreten. Die beiden andern infizierten Schweden sind zwischen 60 und 70 Jahren alt. Gemäss den Forschern kann das Bakterium bei 10% der südschwedischen Zeckenpopulation nachgewiesen werden. [ProMed]

• SUOM;ALAINEN SELVITYS  punkkitaudeista mainitsee myös tämän uuden tulokkaan nimeltä. Se in intrasellulaarinen eikä ilmennä vasta-aineita  vereen ja lisäksi esiintyy henkilöillä joilla on alentunut immuunivaste  tai joilla on ollut  pitkään rituximab hoito. bakteeria ei ole vielä edes pystytty viljelemään eikä olla varma siitä solusta, jossa se esiintyy kehossa, arvellaan kuitenkin että endotelisolussa ja valkoisissa verisoluissa.  hyvä asia kuitenkin että sen aiheuttama  tauti on hoidettavissa doksisykliinillä- ongelma vain on että se on vaikea diagnosoida, ellei se n mahdollisuus tule ensin mieleen. 

  http://www.theseus.fi/bitstream/handle/10024/116647/Saarinen_Saija.pdf;jsessionid=5E97BD2E7F169E2788BED147A525B36F?sequence=1

• Lääkärilehden artikkeli tänään:
• Arya Dadgar, Anna Grankvist, Lennart Wernbro, Christine Wennerås.  Oklar feber hos patient med MS och rituximabbehandling var neoehrlichios. Ny fästingburen infektion som är svår att diagnostisera.
•  http://www.lakartidningen.se/EditorialFiles/6L/%5bEM6L%5d/EM6L.pdf

Läkartidningen 38. Sidorna  1518- 1510. 

Toinenkin punkin kantama bakteeri tunnetaan.. Se aiheuttaa neoehrlichioosia.

xp Appl Acarol. 2016 Mar;68(3):279-97. doi: 10.1007/s10493-015-9935-y. Epub 2015 Jun 17.

Neoehrlichiosis: an emerging tick-borne zoonosis caused by Candidatus Neoehrlichia mikurensis.

Silaghi C¹, Beck R², Oteo JA³, Pfeffer M⁴, Sprong H⁵.

Abstract

Candidatus Neoehrlichia mikurensis is an emerging tick-borne pathogen causing a systemic inflammatory syndrome mostly in persons with underlying hematologic or autoimmune diseases. As it is neither well-known nor well-recognized, it might be misdiagnosed as recurrence of the underlying disease or as an unrelated arteriosclerotic vascular event.

 The pathogen is transmitted by hard ticks of the genus Ixodes and is closely associated with rodents in which transplacental transmission occurs. Transovarial transmission in ticks has not yet been shown. Infection rates vary greatly in ticks and rodents, but the causes for its spatiotemporal variations are largely unknown.

 This review summarizes the current state of knowledge on the geographical distribution and clinical importance of Ca. N. mikurensis. By elucidating the life history traits of this pathogen and determining more accurately its incidence in the human population, a better assessment of its public health relevance can be made.

Most urgent research needs are

•  the in vitro-cultivation of the pathogen,
•  the development of specific serological tests,
•  the determination of the full genomic sequence, 
• the routine implementation of molecular diagnosis in diseased patients with a particular panel of underlying diseases,
•  and promoting the knowledge about neoehrlichiosis among general practitioners, hospital physicians and the risk groups such as forest workers or immune-compromised people to raise awareness about this disease that can easily be treated when correctly diagnosed.

KEYWORDS:

Anaplasmataceae; Apodemus spp.; Candidatus Neoehrlichia mikurenis; Diagnostics; Haematological disorders; Immunodeficiency; Ixodes persulcatus; Ixodes ricinus; Myodes spp.; Rodents; Thrombosis; Treatment

Ruotsin lääkärilehti aloitaa  viimeksimainitusta tärkeästä asiasta:  julkaisee  yksityiskohtaisen potilastapauksen, josa ilmenee kaikki tälle bakteerille tyypilliset seikat ja täten  valaisee ongelmaa ja lisää tietoa tästäkin  anibiootilla hoidetavasta punkkibakteerista Ca. N. mikurensis. 

TBEV ja Borrelia on Ruotsissa endeemistä paikoitellen

 Tämä 17 vuoden takainen  tieto löytyy PubMed hausta- hain  tietoa punkeista joissa on sekä TBEV että Borrelia . Löysin ruotsalaisen kylån Lisö jossa on molempia tauteja väestössä. 

Sieltä tutkittiin 346  yksilöä.  3%;lla  oli aiemmin seropositiivinen TBE  ja enkefaliitin oireita. 10%:lla  oli oltu krooninen  erythema migrans. neljä henkilöä(1%) oli saanut hoidon neuroborrelioosiin ja toiset  neljä krooniseen atrofiseen akrodermatiittiin. 12%:lla oli  TBEV virusvasta-aineita ( 40 henkilöä) ja  26%:lla (89 henkilöllä oli  Borrelia burgdorferi-vasta-aineita. Seroprevalenssi Lyme borrelioosille lisääntyi iän mukana riippuen Lisöllä oloajasta ja punkin puremien määrästä.  TBE:n suhteen oli korrelaatiota vain seropositiivisuudella ja  Lisöllä vietetyllä ajalla.

 Tutkittiin 50 terveeltä verenluovuttajalta  TBEV-vasta-aineaktiivisuudet  eikä havaittu sellaista. Vain yhdellä vernluovuttajista oli vasta-aineita borreliaa vastaan (2%). 

Sitten tutkittiin 150 tukholmalaiselta  TBEV- ja borrelia-vasta-aineaktiivisuudet ja  niitä havaittiin   kahdeksalla ( 8/150,) eli 5%:lla   ja vastaavasti kolmellatoista  ( 13/150) eli  9%:lla.

• Scand J Infect Dis. 1990;22(3):297-306. Prevalence of tick-borne encephalitis and Lyme borreliosis in a defined Swedish population.
• Gustafson R¹, Svenungsson B, Gardulf A, Stiernstedt G, Forsgren M.
• Abstract, Tiivistelmä
• Sera from 346 individuals living on Lisö, an area south of Stockholm, endemic for tick-borne encephalitis (TBE) and Lyme borreliosis, were tested for antibody activity to TBE-virus (TBEV) and Borrelia burgdorferi, using a sonicate antigen, by haemagglutination-inhibition and ELISA, respectively. 10/346 (3%) individuals had a history of previous serologically confirmed TBE with encephalitic symptoms, and 33/346 (10%) had a history of previous erythema chronicum migrans (ECM). Four individuals (1%) had been treated for neuroborreliosis and another 4 (1%) for acrodermatitis chronica atrophicans (ACA). Antibodies to TBEV and B. burgdorferi were detected in 40/346 (12%) and 89/346 (26%) individuals, respectively. The seroprevalence of Lyme borreliosis increased with age, time spent on Lisö, and number of reported tick-bites. For TBE there was a correlation between seropositivity and time spent on Lisö only. In sera from 50 healthy blood-donors, living in a non-endemic area, no antibody activity to TBEV could be detected and only 1/50 (2%) had antibodies to borrelia. In sera from 150 age and sex matched control individuals, living in the city of Stockholm, antibody activity to TBEV and borrelia was found in 8/150 (5%) and 13/150 (9%), respectively.

Hyvä uutinen doxycykliinistä lasten neuroborrelioosissa (D Bremell)

Viime Läjkräiolehti nr 37/2017 antaa lääketieteellisen kommentin:
 Daniel Bremell,  Birger Trollfors.  Doxycyclin kan ges till barn i alla ålder. Ingen risk för missfärgninig av tänder eller emaljhypoplasi.
http://www.lakartidningen.se/Klinik-och-vetenskap/Kommentar/2017/08/Doxycyklin-kan-ges-till-barn-i-alla-aldrar/ 
SITAATTI:
Suomennos:
Ruotsissa diagnostisoidaan vuosittain arviolta useita satoja  lapsia, joilla on neuroborrelioosi (LNB) Kahdeksanvuotiaille ja sitä vanhemmille lapsille suositellaan suunkautta ottaavaksi doxycykliiniä  10- 14 päivää. .
vasta-aiheisena  alle vuotiaille on pidetty  ennemmin tätä lääkettä, doxisykliiniä , koska on arveltu doxisykliinin aiheuttavan (tetrasykliinin tapaan)  hampaitten  värjäytymistä ja/tai kiilteen huonoa muodostumista ( kiillehypoplasiaa), jos  sitä annetaan hampaiden kalkkiutumisjakson aikana.  Sen sijaan on alle kahdeksanvuotiaita  Lymen neuroborrelioosia (LNB)  potevia lapsia hoidettu laskimonsisäisillä  keftriaxoni-antibiooteilla 10-14 päivän  ajan.
Vaikka keftriaksonia annetaan vain kerran päivässä ja  se voidaan tehdä polikliinisen käynnin yhteydessä,  on tällainen suonensisäinen  hoito kuitenkin sekä lapselle että vanhemmille  monimutkaista ja kalliimpaa sekä   vaivalloisempaa kuin suun kautta otettava lääkehoito.

• I Sverige diagnostiseras årligen uppskattningsvis flera hundra barn med neuroborrelios [1]. För barn ≥8 år är den rekommenderade behandlingen peroralt doxy­cyklin i 10–14 dagar [2]. 
• Eftersom doxycyklin har misstänkts kunna orsaka permanent missfärgning av tänderna och/eller emaljhypoplasi om det ges till barn under den period kalcifieringen av tänderna sker är användning till barn <8 10="" barn="" behandlas="" ceftriaxon="" dagar="" enligt="" fass.="" i="" indicerad="" int="" kontra="" llet="" med="" nbsp="" neuroborrelios="" r="" raven="" st="">
• Även om ceftriaxon ges 1 gång per dygn, och därför kan ges poli­kliniskt, är intravenös behandling betydligt omständligare för barn och föräldrar och mer kostsam och arbetskrävande än peroral behandling.

 Vanhemmista tetrasykliinivalmisteista on osoitettu niiden käytön  voivan johtaa lapsilla pysyvään hampaitten värjäytymseen ja /tai hypoplastiseen  kiilteeseen.   Jo vuodesta 1967 on ollut doxysykliiniä käytössä ja sillä on  vähempi affiniteetti kalkkiin kuin vanhemmilla tetrasykliinivalmisteilla, ja sen takia teoreettisesti ottaen  pitäisi hammassivuvaikutusten  riskin olla   vähempi. Aiemmalta ajalta on vain rajallista  kokemusta doxysykliinistä  alle 8-vuotiaille. Kuitenkin on Ricky-Mountain pilkkukuumeessa, eräässa  mahdollisesti hengenvaarallisess rikketsioosissa suositeltu  enisijaiseksi lääkkeeksi  varmistetuissa ja epäillyissä tapauksissa doxisykliiniä vuodesta 1997 alkaen . Suositus tulee  amerikkalaiselta lastenlääkäriyhdistykseltä ja CDC:ltä.  Tästä johtuen on nyt olemassa  suhteellisen suuri määrä lapsia, jotka ovat altistuneet doxysykliinille  jo  syntymästään asti. On julkaistu kolme tutkimusta, jotka käsittävät yhteensä  99 tällaista lasta, jotka  elonsa varhaisvaiheessa ovat saaneet doksisykliiniä ja heidän hammaskuntoansa on verrattu  263 kontrollina toimineeseen  lapseen.   Ei nähty mitään  hammasten värjäytymisiä tai kiilteen muodostushäiriöitä doxisykliiniä saaneilla alle 8 vuotiailla  lapsilla  aivan  3 kuukauden ikäisiin   asti.  Tähän  ja varsinkin näistä tutkimuksista viimeisimpään perustuen CDC suosittelee nykyään  doxysykliiniä  iästä riippumatta varmistettuihin tai epäiltyihin  Anaplasma-, Ehrlichia- tai Borrelia-infektioihin.

• För äldre tetracyklinpreparat är det visat att användning hos barn kan leda till permanent missfärgning av tänder och/eller emaljhypoplasi [3]. 

• Doxycyklin, som funnits tillgängligt sedan 1967, har lägre affinitet för kalcium än äldre tetracyklinpreparat, varför risken för tandbiverkningar teoretiskt bör vara lägre [4]. Det har tidigare funnits begränsad erfarenhet av användning av doxycyklin till barn <8 1997="" alternativa="" amerikanska="" and="" antibiotika="" av="" barnl="" behandling="" centers="" ckfeber="" control="" den="" disease="" dock="" doxycyklin="" effekt="" efter="" f="" fall="" for="" i="" karf="" konstaterade="" likv="" livshotande="" med="" misst="" mountain-fl="" nbsp="" nkta="" och="" potentiellt="" prevention="" r.="" r="" rdig="" rekommenderar="" reningen="" rickettsiosen="" rocky="" rstahandsalternativ="" saknas="" sedan="" som="">
• Detta har gjort att det nu finns ett relativt stort antal barn som exponerats för doxycyklin ända sedan födseln. I tre publicerade studier har man undersökt sammanlagt 99 barn som i låg ålder behandlats med doxycyklin och jämfört deras tandstatus med 263 kontroller [6-8]. Inga fall av tandmissfärgningar eller emaljhypoplasi sågs hos de barn som exponerats för doxycyklin ner till 3 månaders ålder. 
• Baserat på detta och framför allt på den senaste av dessa studier [6] rekommenderar nu CDC doxycyklin även för behandling av barn, oavsett ålder, med bekräftade eller misstänkta infektioner med Anaplasma, Ehrlichia eller Borrelia [9]. 

 Kolmentoista vuoden aikana hoidettin  Göteborgissa Kunigatar Silvian lasten ja nuortensairaalassa vuosittain keskimäärin  42 neuroborrelioosia potevaa lasta, joista  25 oli alle 8-vuotiasta.  Jos tämän extrapoloi koko Ruotsia käsittäväksi se merkitsisi, että useita  alle 8- vuotiaita  lapsia  hoidetaan  neuroborrelioosin takia ja heistä suurin osa saa laskimonsisäistä keftriaxonia. Jos nämä lapset sen sijaan saisivat suun kautta doxysykliiniä,  keventyisi sairanhoidolliset  panostukset ja    kustannukset ja lapsille sekä  vanhemmille hoito yksinkertaistusi huomattavasti.
Ruotsissa doxysykliiniä  on saatavilla   100 mg tabltetteina sekä  mixtuurana 10 mg/ ml( Vibramycin).
Lääkeaineviraston hoitosuoritukset vuodesta 2009 on  ollut  4 mg kehon painokiloa kohden vuorokaudessa kymmenen päivän ajan lapsille,  jotka ovat 8 vuotta tai sen yli. Mainitussa lastensairaalassa  on saatu hyvää kokemusta  annostukseta 8 mg painokiloa kohden  kahtena annoksena päivitäin 10 päivän  ajan maksimaalisen annoksen ollessa  400 mg päivässä.


YHTEENVETONA
 Doxysykliinin käyttöä  alle 8-vuotiaillekin  tukevaa hyvää  tietoa on saatu,  että  siihen ei sisälly pysyväisvauriotten riskiä. Käytettäessä suun kautta otettavaa doxysykliiniä  laskimoon annettavan keftriaxonin sijasta voidaan sensijaan yksinkertaistaa  huomattavasti  alle kahdeksanvuotiaitten neuroborrelioosin hoitoa. . 

•  
  Under en 13-årsperiod behandlades vid Drottning Silvias barn- och ungdomssjukhus i Göteborg i medeltal årligen 42 barn för neuroborrelios, varav årligen 25 barn var <8 2017="" dermark="" g="" i="" iv="" medd="" nbsp="" pers="" r="" s="" teborg="">
  Extrapolerat till hela Sverige innebär detta att flera hundra barn <8 absoluta="" arbetsinsats="" att="" b="" barn="" behandlades="" behandlas="" betydligt="" ceftriaxon.="" de="" den="" dessa="" det="" doxycyklin="" en="" enklare="" f="" i="" inneb="" intraven="" kostnader="" ldrar.="" llet="" majoriteten="" med="" minskad="" minskade="" neuroborrelios="" och="" om="" peroralt="" r="" ra="" rden="" rligen="" sjukv="" skulle="" st="" stor="" ut="" vara="" varav="" ver="" vinst="">
  
  Doxycyklin är i Sverige tillgängligt i tablettform i styrkan 100 mg och som mixtur i koncentration 10 mg/ml (Vibranord). 
  I Läkemedelsverkets behandlingsrekommendationer från 2009 rekommenderas 4 mg/kg kroppsvikt/dygn i 10 dagar till barn ≥8 år [2]. Det finns vid Drottning Silvias barn- och ungdomssjukhus god erfarenhet av dosering 8 mg/kg/dygn till barn ≥8 år, fördelat på 2 doser, i 10 dagar med en maxdos om 400 mg/dygn. 
  
  Sammanfattningsvis finns det nu gott stöd för att användning av doxycyklin till barn <8 anv="" att="" av="" barn="" behandlingen="" best="" betydligt="" br="" ceftriaxon="" d="" dor.="" doxycyklin="" ende="" f="" genom="" hos="" i="" inneb="" inte="" intraven="" kan="" llet="" man="" nda="" neuroborrelios="" peroralt="" r.="" r="" renkla="" risk="" rmed="" ska="" st="">

BORRELIA GENOMI 2017 TIETÄMYS

https://www.ncbi.nlm.nih.gov/pubmed/?term=Borrelia+genome

Pohdittavaksi tämäkin palsmidiasia.
 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310021/

Koska borreliainfektiossa evaasiomekanismeja on useita, eikä niitä edes kokonaan tunneta, borrelia on ehtinyt  kovasti  kohentaa olemassaoloaan  ja on pahasti invasoituvaa lajia, joka hyötyy ilmastonmuutoksesta. 

DNAgyraasi-inhibiittorit 2000

https://www.pharmacology2000.com/Antibacterial/dnagyr1.htm
SITAATTI:

• Mechanism of Action
  • Fluoroquinones represent an important class of antimicrobial which work through inhibition of DNA gyrase.
  • Bacterial DNA gyrase (topoisomerase II) and topoisomerase IV are required for DNA synthesis.
  • Inhibition of DNA gyrase blocks relaxation of supercoiled DNA, relaxation being a requirement for transcription and replication.
  • Inhibition of topoisomerase IV is thought to interfere with sepation of replicated chromosomal DNA
• .Fluoroquinones: Spectrum of Action
  •  Norfloxacin (Noroxin)-least active of the fluoroquinolones
  •  Enoxacin (Penetrex)
  •  Pefloxacin
  •  Ciprofloxacin (Cipro)
  •  Ofloxacin (Floxin)
  •  Lomefloxacin (Maxaquin)
  •  Sparfloxacin (Zagam) {new agent (1998) several times more potent than other currently available fluoroquinolones}

*Ciprofloxacin (Cipro) & Ofloxacin (Floxin):inhibit gram negative cocci and bacilli: Enterobacteriaceae, Pseudomonas, Neisseria, Haemophilus Campylobacter; Staphylococci and streptococci are inhibited; Legionella, Chlamydia, M. tuberculosis, M avium are inhibited;Anaerobes: generally resistant

• Pharmacokinetics
  • After oral administration, bioavailability is good, 80% - 95%.
  • Half-lives range from 3 h (norfloxacin (Noroxin) and ciprofloxacin (Cipro)) to 10 (perfloxacin and fleroxacin)and 20 hours (sparfloxacin (Zagam)).
  • Long half-lives of sparfloxacin (Zagam) and levofloxacin (Levaquin)sparfloxacin and levofloxacin allow once daily dosing.
  • Most flouroquinolones are excreted by the kidney (tubular secretion, may be blocked by probenecid (Benemid)). Sparfloxacin (Zagam) is glucuronidated by the liver then renally cleared
•  Clinical Applications
  • Effective in urinary tract infections (UTI) caused by multidrug resistant strains.
  • Effective for diarrhea caused by Shigella, Salmonella, toxigenic E. coli or Campylobacter infections.
  • Most fluorquinolones that achieve adequate tissue concentrations are effective in treating soft-tissue, bone, and joint infections by multidrug resistant strains of Pseudomonas and Enterobacter.
  • Ciprofloxacin (Cipro): second-line agent for legionellosis.
  • Ciprofloxacin (Cipro)/ofloxacin (Floxin): gonococcal infection.
• Adverse Effects
  • Generally well tolerated
  • Most common side effects are nausea vomiting diarrhea
  • Concurrent administration of theophylline and ciprofloxacin may lead to theophylline toxicity.
  • Fluoroquinolones: damage to growing cartilage (not recommend for use in patients under 18 years old); however, since such damage appears reversible, these drugs may be used in children in some special cases--pseudomonal infections in cystic fibrosis patients.
  •  Contraindicated in nursing mothers--drug excreted in breast milk.

Chambers, H.F. and Jawetz, E.Sulfonamides,Trimethoprim, and Quinolones,in Basic and Clinical Pharmacology,(Katzung, B. G., ed) Appleton-Lange, 1998, p. 765-767.

DNAgyraasi ja Borrelia

https://www.ncbi.nlm.nih.gov/pubmed/?term=DNAgyrase%2C+borrelia

Search results

Items: 15

• Showing results for dna gyrase, borrelia. Search instead for DNAgyrase, borrelia (0)

Select item 158971981.

A superhelical spiral in the Escherichia coli DNA gyrase A C-terminal domain imparts unidirectional supercoiling bias.

Ruthenburg AJ, Graybosch DM, Huetsch JC, Verdine GL.

J Biol Chem. 2005 Jul 15;280(28):26177-84. Epub 2005 May 15.

DNA gyrase is unique among type II topoisomerases in that its DNA supercoiling activity is unidirectional. The C-terminal domain of the gyrase A subunit (GyrA-CTD) is required for this supercoiling bias. We report here the x-ray structure of the Escherichia coli GyrA-CTD (Protein Data Bank code 1ZI0). The E. coli GyrA-CTD adopts a circular-shaped beta-pinwheel fold first seen in the Borrelia burgdorferi GyrA-CTD. However, whereas the B. burgdorferi GyrA-CTD is flat, the E. coli GyrA-CTD is spiral. DNA relaxation assays reveal that the E. coli GyrA-CTD wraps DNA inducing substantial (+) superhelicity, while the B. burgdorferi GyrA-CTD introduces a more modest (+) superhelicity. The observation of a superhelical spiral in the present structure and that of the Bacillus stearothermophilus ParC-CTD structure suggests unexpected similarities in substrate selectivity between gyrase and Topo IV enzymes. We propose a model wherein the right-handed ((+) solenoidal) wrapping of DNA around the E. coli GyrA-CTD enforces unidirectional (-) DNA supercoiling.Free Article

Similar articles

https://www.researchgate.net/figure/7720486_fig1_Figure-1-Reactions-catalyzed-by-DNA-gyrase-and-topoisomerase-IV-a-Representative-DNA


 

Select item 127911462.

Transcriptional regulation of the ospAB and ospC promoters from Borrelia burgdorferi.

Alverson J, Bundle SF, Sohaskey CD, Lybecker MC, Samuels DS.

Mol Microbiol. 2003 Jun;48(6):1665-77.

OspA, OspB and OspC are the major outer surface proteins of Borrelia burgdorferi that are differentially synthesized in response to environmental conditions, including culture temperature. We found that DNA was more negatively supercoiled in B. burgdorferi cultures grown at 23 degrees C compared with cultures grown at 35-37 degrees C. We examined the regulation of ospAB and ospC transcription by temperature and DNA supercoiling. DNA supercoiling was relaxed by adding coumermycin A1, an antibiotic that inhibits DNA gyrase. Syntheses of the major outer surface proteins, expression of the ospA and ospC genes and the activities of the ospAB operon and ospC gene promoters were assayed. ospA product levels decreased, whereas ospC product levels increased after shifting from 23 degrees C to 35 degrees C or after adding coumermycin A1. In addition, OspC synthesis was higher in a gyrB mutant than in wild-type B. burgdorferi. Promoter activity was quantified using cat reporter fusions. Increasing temperature or relaxing supercoiled DNA resulted in a decrease in ospAB promoter activity in B. burgdorferi, but not in Escherichia coli, as well as an increase in ospC promoter activity in both bacteria. ospC promoter activity was increased in an E. coli gyrB mutant with an attenuated DNA supercoiling phenotype. These results suggest that B. burgdorferi senses environmental changes in temperature by altering the level of DNA supercoiling, which then affects the expression of the ospAB operon and the ospC gene. This implies that DNA supercoiling acts as a signal transducer for environmental regulation of outer surface protein synthesis.Free Article

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Select item 123748433.

groEL expression in gyrB mutants of Borrelia burgdorferi.

Alverson J, Samuels DS.

J Bacteriol. 2002 Nov;184(21):6069-72.

GroEL protein and groEL mRNA transcript were up-regulated in gyrB mutants of Borrelia burgdorferi, a causative agent of Lyme disease. Furthermore, the protein and transcript levels in gyrB mutants were greater than those in experimentally heat-shocked cultures of wild-type B. burgdorferi. Circular DNA in the gyrB mutants was more relaxed than in wild-type cells, although groEL is on the linear chromosome of B. burgdorferi. To our knowledge, this is the first evidence, albeit indirect, for the effect of DNA topology on gene expression from a linear DNA molecule in a bacterium.Free PMC Article

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Select item 121424244.

Simultaneous coexpression of Borrelia burgdorferi Erp proteins occurs through a specific, erp locus-directed regulatory mechanism.

El-Hage N, Stevenson B.

J Bacteriol. 2002 Aug;184(16):4536-43.

An individual Borrelia burgdorferi bacterium can encode as many as 13 different Erp (OspE/F-related) proteins from mono-and bicistronic loci that are carried on up to 10 separate plasmids. We demonstrate through multilabel immunofluorescence analyses that individual bacteria simultaneously coexpress their entire Erp protein repertoire. While it has been proposed that B. burgdorferi controls expression of Erp and other plasmid-encoded proteins through changes in DNA topology, we observed regulated Erp expression in the absence of detectable differences in DNA supercoiling. Likewise, inhibition of DNA gyrase had no detectable effect on Erp expression. Furthermore, expression of loci physically adjacent to erp loci was observed to be independently regulated. It is concluded that Erp expression is regulated by a mechanism(s) directed at erp loci and not by a global, plasmid-wide mechanism.Free PMC Article

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Select item 107622445.

Efficient targeted mutagenesis in Borrelia burgdorferi.

Bono JL, Elias AF, Kupko JJ 3rd, Stevenson B, Tilly K, Rosa P.

J Bacteriol. 2000 May;182(9):2445-52.

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.Free PMC Article

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 https://en.wikipedia.org/wiki/Kanamycin_A
 

Select item 107150166.

Disruption of the Borrelia burgdorferi gac gene, encoding the naturally synthesized GyrA C-terminal domain.

Knight SW, Kimmel BJ, Eggers CH, Samuels DS.

J Bacteriol. 2000 Apr;182(7):2048-51.

The C-terminal domain of the A subunit of DNA gyrase, which we term Gac, is naturally synthesized in Borrelia burgdorferi as an abundant DNA-binding protein. Full-length GyrA, which includes the C-terminal domain, is also synthesized by the spirochete and functions as a subunit of DNA gyrase. We have disrupted synthesis of Gac as an independent protein and demonstrated that it is not essential for growth in a coumarin-resistant background. We detected no alterations in DNA maintenance, condensation, or topology in B. burgdorferi lacking this small DNA-binding protein.

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Select item 111195607.

Homologous and heterologous Borrelia burgdorferi challenge of infection-derived immune rabbits using host-adapted organisms.

Shang ES, Wu XY, Lovett MA, Miller JN, Blanco DR.

Infect Immun. 2001 Jan;69(1):593-8.

We have recently found that strain B31 infection-immune rabbits are completely protected against homologous challenge with large numbers (>10(6)) of host-adapted Borrelia burgdorferi (HAB) (E. S. Shang, C. I. Champion, X. Wu, J. T. Skare, D. B. Blanco, J. N. Miller, and M. A. Lovett, Infect. Immun. 68:4189-4199, 2000). In this study, we have extended these findings to determine whether B31 strain infection-immune rabbits are also protected against heterologous HAB challenge. Infection-immune rabbits challenged with large numbers (>10(6)) of homologous HAB strain B31 were completely protected from erythema migrans (EM) and skin and disseminated infection. In contrast, infection-immune rabbits challenged with heterologous HAB strains N40 and Sh-2-82 were completely susceptible to EM and skin and disseminated infection; challenge with strain 297 also resulted in EM and infection of the skin and viscera, but clearance of infection occurred 3 weeks postchallenge. These findings confirm that immunity elicited in rabbits by B31 strain infection confers complete protection against large-dose homologous HAB challenge but not against a heterologous strain.Free PMC Article

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Select item 104696658.

Natural synthesis of a DNA-binding protein from the C-terminal domain of DNA gyrase A in Borrelia burgdorferi.

Knight SW, Samuels DS.

EMBO J. 1999 Sep 1;18(17):4875-81.

We have identified a 34 kDa DNA-binding protein with an HU-like activity in the Lyme disease spirochete Borrelia burgdorferi. The 34 kDa protein is translated from an abundant transcript initiated within the gene encoding the A subunit of DNA gyrase. Translation of the 34 kDa protein starts at residue 499 of GyrA and proceeds in the same reading frame as full-length GyrA, resulting in an N-terminal-truncated protein. The 34 kDa GyrA C-terminal domain, although not homologous, substitutes for HU in the formation of the Type 1 complex in Mu transposition, and complements an HU-deficient strain of Escherichia coli. This is the first example of constitutive expression of two gene products in the same open reading frame from a single gene in a prokaryotic cellular system.Free PMC Article

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Select item 97972249.

Mutations in Bartonella bacilliformis gyrB confer resistance to coumermycin A1.

Battisti JM, Smitherman LS, Samuels DS, Minnick MF.

Antimicrob Agents Chemother. 1998 Nov;42(11):2906-13.

This study describes the first isolation and characterization of spontaneous mutants conferring natural resistance to an antibiotic for any Bartonella species. The Bartonella bacilliformis gyrB gene, which encodes the B subunit of DNA gyrase, was cloned and sequenced. The gyrB open reading frame (ORF) is 2,079 bp and encodes a deduced amino acid sequence of 692 residues, corresponding to a predicted protein of approximately 77.5 kDa. Sequence alignment indicates that B. bacilliformis GyrB is most similar to the GyrB protein from Bacillus subtilis (40.1% amino acid sequence identity) and that it contains the longest N-terminal tail (52 residues) of any GyrB characterized to date. The cloned B. bacilliformis gyrB was expressed in an Escherichia coli S30 cell extract and was able to functionally complement a temperature-sensitive E. coli Cour gyrB mutant (strain N4177). We isolated and characterized spontaneous mutants of B. bacilliformis resistant to coumermycin A1, an antibiotic that targets GyrB. Sequence analysis of gyrB from 12 Cour mutants of B. bacilliformis identified single nucleotide transitions at three separate loci in the ORF. The predicted amino acid substitutions resulting from these transitions are Gly to Ser at position 124 (Gly124-->Ser), Arg184-->Gln, and Thr214-->Ala or Thr214-->Ile, which are analogous to mutated residues found in previously characterized resistant gyrB genes from Borrelia burgdorferi, E. coli, Staphylococcus aureus, and Haloferax sp. The Cour mutants are three to five times more resistant to coumermycin A1 than the wild-type parental strainFree PMC Article

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Select item 904312710.

Oligonucleotide-mediated genetic transformation of Borrelia burgdorferi.

Samuels DS, Garon CF.

Microbiology. 1997 Feb;143 ( Pt 2):519-22.

We have used short oligonucleotides to genetically transform the Lyme disease spirochaete Borrelia burgdorferi. The oligonucleotides are derived from the sequence of an Arg-133 to Ile mutant gyrB (chromosomal) gene that confers resistance to the antibiotic coumermycin A1. Oligonucleotides were about 10,000-fold less efficient at transformation, on a molar basis, than longer PCR-generated substrates. All of the transformants tested contained the predicted site-directed silent mutation in their gyrB genes. Antisense oligonucleotides were more efficient at transformation than either sense or double-stranded oligonucleotides. This is the first demonstration of oligonucleotides used to introduce site-directed mutations directly into the genome of a bacterium.

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Select item 883069111.

Directed insertion of a selectable marker into a circular plasmid of Borrelia burgdorferi.

Rosa P, Samuels DS, Hogan D, Stevenson B, Casjens S, Tilly K.

J Bacteriol. 1996 Oct;178(20):5946-53.

Studies of the biology of Borrelia burgdorferi and the pathogenesis of Lyme disease are severely limited by the current lack of genetic tools. As an initial step toward facile genetic manipulation of this pathogenic spirochete, we have investigated gene inactivation by allelic exchange using a mutated borrelial gyrB gene that confers resistance to the antibiotic coumermycin A1 as a selectable marker. We have transformed B. burgdorferi by electroporation with a linear fragment of DNA in which this selectable marker was flanked by sequences from a native borrelial 26-kb circular plasmid. We have identified coumermycin A1-resistant transformants in which gyrB had interrupted the targeted site on the 26-kb plasmid via homologous recombination with the flanking sequences. Antibiotic resistance conferred by the mutated gyrB gene on the plasmid is dominant, and transformed spirochetes carrying this plasmid do not contain any unaltered copies of the plasmid. Coumermycin A1 resistance can be transferred to naive B. burgdorferi by transformation with borrelial plasmid DNA from the initial transformants. This work represents the first example of a directed mutation in B. burgdorferi whereby a large segment of heterologous DNA (gyrB) has been inserted via homologous recombination with flanking sequences, thus demonstrating the feasibility of specific gene inactivation by allelic exchange.Free PMC Article

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Select item 792896512.

Genetic transformation of the Lyme disease agent Borrelia burgdorferi with coumarin-resistant gyrB.

Samuels DS, Mach KE, Garon CF.

J Bacteriol. 1994 Oct;176(19):6045-9.

No useful method to genetically manipulate Borrelia burgdorferi, the causative agent of Lyme disease, has been developed previously. We have used resistance to the coumarin antibiotic coumermycin A1, an inhibitor of DNA gyrase, as a genetic marker to monitor the transformation of B. burgdorferi by electroporation. Introduction of site-directed mutations into the gyrB gene demonstrated that transformation was successful, provided evidence that homologous recombination occurs on the chromosome, and established that mutations at Arg-133 of DNA gyrase B confer coumermycin A1 resistance in B. burgdorferi. The coumermycin A1-resistant gyrB marker and genetic transformation can now be applied toward dissecting the physiology and pathogenesis of the Lyme disease agent on a molecular genetic levelFree PMC Article

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Select item 818860913.

gyrB mutations in coumermycin A1-resistant Borrelia burgdorferi.

Samuels DS, Marconi RT, Huang WM, Garon CF.

J Bacteriol. 1994 May;176(10):3072-5.

We have isolated and characterized mutants of Borrelia burgdorferi that are resistant to the antibiotic coumermycin A1, which targets the B subunit of DNA gyrase. Mutants had either 100- or 300-fold higher resistance to coumermycin A1 than wild-type B. burgdorferi. In each case, a single point mutation in the gyrB gene converted Arg-133 to Gly or Ile. Mutations in the homologous Arg residue of Escherichia coli DNA gyrase are also associated with resistance to coumarin antimicrobial agents.Free PMC Article

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Select item 838163914.

Coumermycin A1 inhibits growth and induces relaxation of supercoiled plasmids in Borrelia burgdorferi, the Lyme disease agent.

Samuels DS, Garon CF.

Antimicrob Agents Chemother. 1993 Jan;37(1):46-50.

Coumermycin A1 is an inhibitor of DNA gyrase, an enzyme that catalyzes supercoiling of DNA and is required for bacterial DNA replication. We have investigated the activity of this coumarin antibiotic on Borrelia burgdorferi, a spirochete and the causative agent of Lyme disease. B. burgdorferi was more susceptible than many other eubacteria to coumermycin as well as novobiocin, another coumarin antibiotic; this contrasted with its relative resistance to the DNA gyrase inhibitors nalidixic acid, oxolinic acid, and ciprofloxacin. Coumermycin at 0.2 micrograms/ml inhibited the growth of B. burgdorferi B31 in BSK II medium. A 100-fold-lower concentration induced the relaxation of two negatively supercoiled circular plasmids within 2 h. Plasmid supercoiling was restored within 2 h of removal of coumermycin. These results suggest that B. burgdorferi has a DNA gyrase and that this enzyme's activity is required for growth. Furthermore, structural analogs of coumermycin may be considered as treatments for Lyme disease.Free PMC Article

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 https://en.wikipedia.org/wiki/Coumermycin_A1

 

Select item 164475015.

Linear- and circular-plasmid copy numbers in Borrelia burgdorferi.

Hinnebusch J, Barbour AG.

J Bacteriol. 1992 Aug;174(16):5251-7.

Borrelia burgdorferi, the Lyme disease agent, and other members of the spirochetal genus Borrelia have double-stranded linear plasmids in addition to supercoiled circular plasmids. The copy number relative to the chromosome was determined for 49- and 16-kb linear plasmids and a 27-kb circular plasmid of the type strain, B31, of B. burgdorferi.

 All three plasmids were present in low copy number, about one per chromosome equivalent, as determined by relative hybridizations of replicon-specific DNA probes. The low copy number of Borrelia plasmids suggests that initiation of DNA replication and partitioning are carefully controlled during the cell division cycle. The copy numbers of these three plasmids of strain B31 were unchanged after approximately 7,000 generations in continuous in vitro culture. A clone of B. burgdorferi B31 that did not contain the 16-kb linear plasmid was obtained after exposure of a culture to novobiocin, a DNA gyrase inhibitor. The plasmid-cured strain contains only one linear plasmid, the 49-kb plasmid, and thus has the smallest genome reported to date for B. burgdorferi.Free PMC Article

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