Neisseria gonorrhoeae: Difference between revisions

Jump to navigation Jump to search
m (Bot: Removing from Primary care)
 
(34 intermediate revisions by 5 users not shown)
Line 1: Line 1:
{{gonorrhea}}
{{Taxobox
{{Taxobox
| color = lightgrey
| color = lightgrey
Line 16: Line 17:
}}
}}
__NOTOC__
__NOTOC__
{{SI}}
{{About0|gonorrhea}}
{{CMG}}
{{CMG}}
==Overview==
==Overview==
'''''Neisseria gonorrhoeae''''', also known as '''''gonococci''''' (plural), or '''''gonococcus''''' (singular), is a species of [[Gram-negative]] coffee bean-shaped [[diplococci]] [[bacteria]] responsible for the [[sexually transmitted infection]] [[gonorrhea]].<ref name=Sherris>{{cite book |editor1-last=Ryan |editor1-first=KJ |editor2-last=Ray |editor2-first=CG |title=Sherris Medical Microbiology | edition = 4th | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 }}</ref>
''N. gonorrhoeae'' was first described by [[Albert Ludwig Sigesmund Neisser|Albert Neisser]] in 1879.


'''''Neisseria gonorrhoeae''''' (also known as ''Gonococci'') is a species of [[Gram-negative]] [[bacteria]] responsible for the [[sexually transmitted disease]] [[gonorrhoea]].<ref name=Sherris>{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0838585299 }}</ref> ''Neisseria'' are highly [[Growth medium|fastidious]] cocci, requiring nutrient supplementation to survive. Thus, they grow on [[Chocolate agar]] (heated blood agar) with carbon dioxide. These cocci are facultatively intracellular and typically appear in pairs ([[diplococci]]).
== Microbiology ==
''[[Neisseria]]'' are fastidious Gram-negative cocci that require nutrient supplementation to grow in laboratory cultures. To be specific, they grow on [[chocolate agar]] with [[carbon dioxide]]. These cocci are facultatively intracellular and typically appear in pairs (diplococci), in the shape of coffee beans. Of the eleven species of ''Neisseria'' that colonize humans, only two are pathogens. ''N. gonorrhoeae'' is the causative agent of [[gonorrhea]] (also called "The Clap") and is transmitted via sexual contact.<ref name= GencoWetzler>{{cite book |editor1-last=Genco |editor1-first=C |editor2-last=Wetzler |editor2-first=L |year=2010 |title=Neisseria: Molecular Mechanisms of Pathogenesis |publisher=Caister Academic Press |isbn=978-1-904455-51-6}}</ref>


Gonorrhoea symptoms include a purulent (or [[pus]]-like) discharge from the genitals which may be foul smelling, a burning sensation during [[urination]] and [[conjunctivitis]] commonly in neonates; that's why [[silver nitrate]] is used as a preventive measure. It also occurs occasionally in adults. ''Neisseria'' is usually isolated on a [[Thayer-Martin agar]] &mdash; an [[agar plate]] with 3 different [[antibiotic]]s and nutrients which not only facilitate the growth of ''Neisseria'' species, but inhibit the growth of [[Gram-positive]] organisms and most bacilli and fungi. Further testing to differentiate the species includes testing for [[oxidase]] (all ''Neisseria'' show a positive reaction) and the [[carbohydrates]] [[maltose]], [[sucrose]], and [[glucose]] test in which ''N. gonorrhoeae'' will only oxidize (that is, utilize) the glucose.
''Neisseria'' is usually isolated on [[Thayer-Martin agar]] (or VPN agar)—an [[agar plate]] containing [[antibiotic]]s ([[vancomycin]], [[colistin]], [[nystatin]], and [[trimethoprim]]) and nutrients that facilitate the growth of ''Neisseria'' species while inhibiting the growth of contaminating bacteria and fungi. Further testing to differentiate the species includes testing for [[oxidase]] (all clinically relevant ''Neisseria'' show a positive reaction) and the [[carbohydrates]] [[maltose]], [[sucrose]], and [[glucose]] test in which ''N. gonorrhoeae'' will oxidize (that is, utilize) only the glucose.


If ''N. gonorrhoeae'' is [[Antibiotic resistance|resistant]] to the [[penicillin]] family of antibiotics, then [[ceftriaxone]] (a third-generation [[cephalosporin]]) is often used.
''N. gonorrhoeae'' are non-motile and possess type IV pili to adhere to surfaces. The type IV pili operate mechanistically similar to a grappling hook. Pili extend and attach to a [[Substrate (biology)|substrate]] that signals the pilus to retract, dragging the cell forward. ''N. gonorrhoeae'' are able to pull 100,000 times their own weight, and it has been claimed that the pili used to do so are the strongest biological motor known to date, exerting one nanonewton.<ref>{{cite journal |author=Biais N, Ladoux B, Higashi D, So M, Sheetz M |title=Cooperative retraction of bundled type IV pili enables nanonewton force generation |journal=PLoS Biol. |volume=6 |issue=4 |pages=e87 |year=2008 |pmid=18416602 |pmc=2292754 |doi=10.1371/journal.pbio.0060087 |url=http://dx.plos.org/10.1371/journal.pbio.0060087 |laysummary=http://www.newscientist.com/article/mg19826525.300-mighty-microbe-pulls-100000-times-its-bodyweight.html |laydate=19 April 2008 |laysource=New Scientist}}</ref>


Patients should also be tested for ''[[Chlamydia]]'' infections, since co-infection is frequent.
''N. gonorrhoeae'' has surface proteins called Opa proteins, which bind to receptors on immune cells. In so doing, ''N. gonorrhoeae'' is able to prevent an immune response. The host is also unable to develop an immunological memory against ''N. gonorrhoeae'' – which means that future reinfection is possible. ''N. gonorrhoeae'' can also evade the immune system through a process called [[antigenic variation]], in which the ''N. gonorrhoeae'' bacterium is able to alter the antigenic determinants (sites where antibodies bind) such as the Opa proteins<ref>{{cite journal |doi=10.1016/0092-8674(86)90366-1|pmid=3093085|title=Opacity genes in ''Neisseria gonorrhoeae'': Control of phase and antigenic variation|journal=Cell|volume=47|issue=1|pages=61–71|year=1986|last1=Stern|first1=Anne|last2=Brown|first2=Melissa|last3=Nickel|first3=Peter|last4=Meyer|first4=Thomas F.}}</ref> and Type IV pili<ref>{{cite journal |doi=10.1111/j.1365-2958.2011.07773.x|pmid=21812841|title=Focusing homologous recombination: Pilin antigenic variation in the pathogenic Neisseria|journal=Molecular Microbiology|volume=81|issue=5|pages=1136–43|year=2011|last1=Cahoon|first1=Laty A.|last2=Seifert|first2=H. Steven}}</ref> that adorn its surface. The many permutations of surface proteins make it more difficult for immune cells to recognize ''N. gonorrhoeae'' and mount a defense.<ref>[http://blog.advocatesaz.org/2011/04/11/sti-awareness-gonorrhea/ STI Awareness: Gonorrhea]. Planned Parenthood Advocates of Arizona. 11 April 2011. Retrieved 31 August 2011.</ref>


==Diagnosis==  
''N. gonorrhoeae'' is naturally competent for DNA transformation as well as being capable of conjugation. These processes allow for the DNA of ''N. gonorrhoeae'' to acquire or spread new genes. Especially dangerous from the aspect of healthcare is the ability to conjugate, since this can lead to antibiotic resistance.<ref>{{cite journal |doi=10.1046/j.1365-2958.2002.03193.x|pmid=12410832|title=Competence for natural transformation in ''Neisseria gonorrhoeae'': Components of DNA binding and uptake linked to type IV pilus expression|journal=Molecular Microbiology|volume=46|issue=3|pages=749–60|year=2002|last1=Aas|first1=Finn Erik|last2=Wolfgang|first2=Matthew|last3=Frye|first3=Stephan|last4=Dunham|first4=Steven|last5=Løvold|first5=Cecilia|last6=Koomey|first6=Michael}}</ref>
===Pathology===
<gallery widths=300px>
<gallery widths=300px>
N. gonorrhea (GN diplococci).jpg | N. gonorrhea (gn diplococci) in conjunctivitis.<ref>http://picasaweb.google.com/mcmumbi/USMLEIIImages</ref>
N. gonorrhea (GN diplococci).jpg | N. gonorrhea (Gram-negative diplococci) in conjunctivitis.<ref>http://picasaweb.google.com/mcmumbi/USMLEIIImages</ref>
</gallery>
</gallery>
== Genome ==
The genomes of several strains of ''N''. ''gonorrhoeae ''have been sequenced. Most of them are about 2.1 Mb in size and encode 2,100 to 2,600 proteins (although most seem to be in the lower range).<ref>[https://www.broadinstitute.org/annotation/genome/neisseria_gonorrhoeae/GenomeStats.html ''Neisseria gonorrhoeae'' genome statistics, Broad Institute]</ref> For instance, '''strain NCCP11945''' consists of one circular chromosome (2,232,025 bp) encoding 2,662 predicted [[open reading frame|ORFs]] and one [[plasmid]] (4,153 bp) encoding 12 predicted ORFs. The estimated coding density over the entire genome is 87%, and the average G+C content is 52.4%, values that are similar to those of strain FA1090. The NCCP11945 genome encodes 54 tRNAs and four copies of 16S-23S-5S rRNA operons.<ref name="Chung2008">{{Cite pmid| 18586945}}</ref>


==Treatment==
In 2011, researchers at Northwestern University found evidence of a human DNA fragment in a ''Neisseria gonorrhoeae'' genome, the first example of [[horizontal gene transfer]] from humans to a bacterial pathogen.<ref>{{cite journal |doi=10.4161/mge.1.1.15868 |pmid=22016852 |pmc=3190277 |laysummary=http://www.sciencedaily.com/releases/2011/02/110213174143.htm |laysource=ScienceDaily |laydate=February 14, 2011|title=''Neisseria gonorrhoeae'' and humans perform an evolutionary LINE dance |journal=Mobile Genetic Elements |volume=1 |issue=1 |pages=85–87 |year=2014 |last1=Anderson |first1=Mark T. |last2=Seifert |first2=H. Steven }}</ref><ref name=anderson2011>{{cite journal |doi=10.1128/mBio.00005-11 |pmid=21325040|pmc=3042738|author1=Anderson|first1=M. T.|title=Opportunity and Means: Horizontal Gene Transfer from the Human Host to a Bacterial Pathogen|journal=MBio|volume=2|issue=1|pages=e00005–11|last2=Seifert|first2=H. S.|year=2011}}</ref>


* '''Neisseria gonorrhoeae'''<ref>{{Cite journal| issn = 1545-8601| volume = 64| issue = RR-03| pages = 1–137| last1 = Workowski| first1 = Kimberly A.| last2 = Bolan| first2 = Gail A.| title = Sexually transmitted diseases treatment guidelines, 2015| journal = MMWR. Recommendations and reports: Morbidity and mortality weekly report. Recommendations and reports / Centers for Disease Control| date = 2015-06-05| pmid = 26042815}}</ref>
==Transmission==
:* '''1. Gonococcal infections in adolescents and adults'''
''N. gonorrhoeae'' is transmitted from person to person during sexual relations. Traditionally, the bacteria was thought to move attached to [[spermatozoon]], but this hypothesis did not explain female to male transmission of the disease. A recent study suggests that rather than “surf” on wiggling [[sperm]], ''N. gonorrhoeae'' bacteria uses hairlike structures called [[pilus|pili]] to anchor onto proteins in the sperm and move through coital liquid.<ref name=Anderson2014>{{cite journal |doi=10.1128/mBio.01004-13|pmid=24595372|title=Seminal Plasma Initiates a ''Neisseria gonorrhoeae'' Transmission State|journal=MBio|volume=5|issue=2|pages=e01004–13|year=2014|last1=Anderson|first1=M. T.|last2=Dewenter|first2=L.|last3=Maier|first3=B.|last4=Seifert|first4=H. S.}}</ref>
::* '''1.1 Uncomplicated gonococcal infections of the cervix, urethra, and rectum'''
:::* Preferred regimen: [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose
:::* Alternative regimen: [[Cefixime]] 400 mg PO in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose (if ceftriaxone is not available)


::*'''1.2 Uncomplicated gonococcal infections of the pharynx'''
==Survival of gonococci==
:::* Preferred regimen: [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose
The exudates from infected individuals contain many polymorphonuclear leukocytes (PMN) with ingested ''gonococci''. These ''gonococci'' stimulate the PMN to release an internal oxidative burst involving reactive oxygen species in order to kill the ''gonococci''.<ref>{{cite journal |doi=10.1128/iai.73.4.1971-1977.2005|pmid=15784537|pmc=1087443|title=Interactions of ''Neisseria gonorrhoeae'' with Adherent Polymorphonuclear Leukocytes|journal=Infection and Immunity|volume=73|issue=4 |pages=1971–7|year=2005|last1=Simons|first1=M. P.|last2=Nauseef|first2=W. M.|last3=Apicella|first3=M. A.}}</ref> However, a significant fraction of the ''gonococci'' can resist killing and are able to reproduce within the PMN phagosomes.


::::* '''1.2.1 Management of sex partners'''
Stohl and Seifert showed that the bacterial RecA protein, that mediates recombinational repair of DNA damage, plays an important role in ''gonococcal'' survival.<ref>{{cite journal |doi=10.1128/JB.00801-06|pmid=16936020|pmc=1636252|title=''Neisseria gonorrhoeae'' DNA Recombination and Repair Enzymes Protect against Oxidative Damage Caused by Hydrogen Peroxide|journal=Journal of Bacteriology|volume=188|issue=21 |pages=7645–51|year=2006|last1=Stohl|first1=E. A.|last2=Seifert|first2=H. S.}}</ref> The protection afforded by RecA protein may be linked to transformation, the process by which recipient ''gonococci'' take up DNA from neighboring ''gonococci'' and integrate this DNA into the recipient genome through recombination. Michod et al. have suggested that an important benefit of transformation in ''N. gonorrhoeae'' may be recombinational repair of oxidative DNA damages caused by oxidative attack by the hosts phagocytic cells.<ref>{{cite journal |doi=10.1016/j.meegid.2008.01.002|pmid=18295550|title=Adaptive value of sex in microbial pathogens|journal=Infection, Genetics and Evolution|volume=8|issue=3 |pages=267–85|year=2008|last1=Michod|first1=Richard E.|last2=Bernstein|first2=Harris|last3=Nedelcu|first3=Aurora M.}}</ref>
:::::* Expedited partner therapy: [[Cefixime]] 400 mg PO in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose
:::::* Recent sex partners (i.e., persons having sexual contact with the infected patient within the 60 days preceding onset of symptoms or gonorrhea diagnosis) should be referred for evaluation, testing, and presumptive dual treatment.  
:::::* If the patient’s last potential sexual exposure was >60 days before onset of symptoms or diagnosis, the most recent sex partner should be treated.
:::::* To avoid reinfection, sex partners should be instructed to abstain from unprotected sexual intercourse for 7 days after they and their sexual partner(s) have completed treatment and after resolution of symptoms, if present.


::::* '''1.2.2 Allergy, intolerance, and adverse reactions'''
==Gallery==
:::::* Preferred regimen (1): [[Gemifloxacin]] 320 mg PO in a single dose {{and}} [[Azithromycin]] 2 g PO in a single dose
<gallery>
:::::* Preferred regimen (2): [[Gentamicin]] 240 mg IM in a single dose {{and}} [[Azithromycin]] 2 g PO in a single dose
:::::: Note: Use of ceftriaxone or cefixime is contraindicated in persons with a history of an IgE-mediated penicillin allergy (e.g., anaphylaxis, Stevens Johnson syndrome, and toxic epidermal necrolysis).


::::* '''1.2.3 Pregnancy'''
Image: Gonorrhea10.jpeg| Photomicrograph of Gram-negative Neisseria gonorrhoeae bacteria, accompanied by a number of polymorphonuclear leukocytes (PMN). <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
:::::* Preferred regimen: [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose


::::* '''1.2.4 Suspected cephalosporin treatment failure'''
Image: Gonorrhea02.jpeg| 3D computer-generated image of drug-resistant Neisseria gonorrhoeae diplococcal bacteria. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
:::::* Preferred regimen: [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose
Image: Gonorrhea06.jpeg| Gram-stained photomicrograph revealed gram-negative diplococcal bacteria, Neisseria gonorrhoea. <SMALL><SMALL>''[http://phil.cdc.gov/phil/home.asp From Public Health Image Library (PHIL).] ''<ref name=PHIL> {{Cite web | title = Public Health Image Library (PHIL) | url = http://phil.cdc.gov/phil/home.asp}}</ref></SMALL></SMALL>
:::::* Alternative regimen (1): [[Gemifloxacin]] 320 mg PO  single dose  {{and}} [[Azithromycin]] 2 g PO  single dose (when isolates have elevated cephalosporin MICs)
:::::* Alternative regimen (2): [[Gentamicin]] 240 mg IM  single dose {{and}} [[Azithromycin]] 2 g PO single dose (when isolates have elevated cephalosporin MICs)
:::::* Alternative regimen (3): [[Ceftriaxone]] 250 mg IM as a single dose {{and}} [[Azithromycin]] 2 g PO as a single dose (failure after treatment with cefixime and azithromycin)
:::::: Note: Treatment failure should be considered in: (1) persons whose symptoms do not resolve within 3–5 days after appropriate treatment and report no sexual contact during the post-treatment follow-up period; (2) persons with a positive test-of-cure (i.e., positive culture ≥ 72 hours or positive NAAT ≥ 7 days after receiving recommended treatment) when no sexual contact is reported during the post-treatment follow-up period; (3) persons who have a positive culture on test-of-cure (if obtained) if there is evidence of decreased susceptibility to cephalosporins on antimicrobial susceptibility testing, regardless of whether sexual contact is reported during the post-treatment follow-up period.
 
::* '''1.3 Gonococcal conjunctivitis'''
:::* Preferred regimen: [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1 g PO in a single dose
:::: Note: Consider one-time lavage of the infected eye with saline solution.
 
::::* '''1.3.1 Management of sex partners'''
:::::* Patients should be instructed to refer their sex partners for evaluation and treatment.  
 
::* '''1.4 Disseminated gonococcal infection''' 
:::* '''1.4.1 Arthritis and arthritis-dermatitis syndrome '''
::::* Preferred regimen: [[Ceftriaxone]] 1 g IM/IV q24h for 7 days {{and}} [[Azithromycin]] 1 g PO in a single dose
::::* Alternative regimen: [[Cefotaxime]] 1 g IV q8h for 7 days {{or}} [[Ceftizoxime]] 1 g IV q 8 h  for 7 days {{and}} [[Azithromycin]] 1 g PO in a single dose
 
:::* '''1.4.2 Gonococcal meningitis and endocarditis'''
::::* Preferred regimen : [[Ceftriaxone]] 1-2 g IV  q 12-24 h  for 10-14 days {{and}} [[Azithromycin]] 1 g PO in a single dose
 
:* '''2. Gonococcal Infections Among Neonate'''
::* '''2.1 Ophthalmia neonatorum caused by N. gonorrhoeae'''
::* Preferred regimen: [[Ceftriaxone]] 25-50 mg/kg IV or IM in a single dose, not to exceed 125 mg
 
::*''' Disseminated Gonococcal Infection and Gonococcal Scalp Abscesses in Neonates'''
::*Preferred regimen : [[Ceftriaxone]] 25-50 mg/kg/day  IM/IV qd for 7 days {{or}} [[Cefotaxime]] 25 mg/kg IV /IM  q12h for 7 days.
::*Note:The  duration of  treatment is 10-14 days if meningitis is documented 
::*'''Treatment of  Neonates Born to Mothers Who Have Gonococcal Infection in the Absence of Signs of Gonococcal Infection'''
::* Preferred regimen : [[Ceftriaxone]] 25-50 mg/kg/day  IM/IV in a single dose, not to exceed 125 mg
 
::* '''Gonococcal Infections Among Infants and Children '''
::* Infants and Children Who Weigh ≤45 kg and Who Have Uncomplicated Gonococcal Vulvovaginitis, Cervicitis, Urethritis, Pharyngitis, or Proctitis
::* Preferred regimen : [[Ceftriaxone]] 25-50 mg/kg/day  IM/IV in a single dose, not to exceed 125 mg 
::*Children Who Weigh >45 kg and Who Have Uncomplicated Gonococcal Vulvovaginitis, Cervicitis, Urethritis, Pharyngitis, or Proctitis
::* Preferred regimen : [[Ceftriaxone]] 250 mg IM in a single dose {{and}} [[Azithromycin]] 1g PO in a single dose
::* Alternative regimen: [[Cefixime]] 400 mg PO  single dose {{and}} [[Azithromycin]] 1 g PO single dose.(If ceftriaxone is not available)
::*Children Who Weigh ≤45 kg and Who Have Bacteremia or Arthritis
::* Preferred regimen : [[Ceftriaxone]] 50 mg/kg (maximum dose: 1 g) IM or IV  q 24 h for 7 days 
::*Children Who Weigh >45 kg and Who Have Bacteremia or Arthritis
::* Preferred regimen : [[Ceftriaxone]] 1 g IM /IV q 24  for 7 days
 
==Prophylaxis==
 
* Neisseria gonorrhoeae<ref>{{Cite journal| issn = 1545-8601| volume = 64| issue = RR-03| pages = 1–137| last1 = Workowski| first1 = Kimberly A.| last2 = Bolan| first2 = Gail A.| title = Sexually transmitted diseases treatment guidelines, 2015| journal = MMWR. Recommendations and reports: Morbidity and mortality weekly report. Recommendations and reports / Centers for Disease Control| date = 2015-06-05| pmid = 26042815}}</ref>
:* '''1. Ophthalmia neonatorum'''
::* Preferred regimen: [[Erythromycin]] (0.5%) ophthalmic ointment in each eye in a single application at birth
::* Alternative regimen: [[Ceftriaxone]] 25–50 mg/kg IV/IM in a single dose, not to exceed 125 mg (if erythromycin ointment is not available)


</gallery>
==References==
==References==
{{Reflist|2}}
{{refbegin}}
{{Reflist}}
*{{cite web |first=Kenneth |last=Todar |title=Pathogenic Neisseriae: Gonorrhea, Neonatal Ophthalmia and Meningococcal Meningitis |work=Todar's Online Textbook of Bacteriology |url=http://www.textbookofbacteriology.net/neisseria.html}}
*{{EMedicine|article|218059|Gonorrhea}}
{{Gram-negative bacterial diseases}}


[[Category:Gram negative bacteria]]
[[Category:Proteobacteria]]
[[Category:Infectious disease]]
[[Category:Infectious Disease Project]]
[[Category:Infectious Disease Project]]
[[Category:Gynecology]]

Latest revision as of 22:56, 29 July 2020

Sexually transmitted diseases Main Page

Gonorrhea Microchapters

Home

Patient Info

Overview

Historical perspective

Classification

Pathophysiology

Causes

Differentiating Gonorrhea from other Diseases

Epidemiology and Demographics

Risk Factors

Screening

Natural History, Complications, and Prognosis

Diagnosis

History and Symptoms

Physical Examination

Laboratory Findings

Other Diagnostic Studies

Treatment

Medical Therapy

Antibiotic Resistance

Primary Prevention

Secondary Prevention

Cost-Effectiveness of Therapy

Future or Investigational Therapies

Case Studies

Case #1

Neisseria gonorrhoeae On the Web

Most recent articles

Most cited articles

Review articles

CME Programs

Powerpoint slides

Images

American Roentgen Ray Society Images of Neisseria gonorrhoeae

All Images
X-rays
Echo & Ultrasound
CT Images
MRI

Ongoing Trials at Clinical Trials.gov

US National Guidelines Clearinghouse

NICE Guidance

FDA on Neisseria gonorrhoeae

CDC on Neisseria gonorrhoeae

Neisseria gonorrhoeae in the news

Blogs on Neisseria gonorrhoeae

Directions to Hospitals Treating Gonorrhea

Risk calculators and risk factors for Neisseria gonorrhoeae

Neisseria gonorrhoeae
Neisseria gonorrhoeae cultured on two different media types.
Neisseria gonorrhoeae cultured on two different media types.
Scientific classification
Kingdom: Bacteria
Phylum: Proteobacteria
Class: Beta Proteobacteria
Order: Neisseriales
Family: Neisseriaceae
Genus: Neisseria
Species: N. gonorrhoeae
Binomial name
Neisseria gonorrhoeae
Zopf, 1885
This page is about microbiologic aspects of the organism(s).  For clinical aspects of the disease, see gonorrhea.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

Neisseria gonorrhoeae, also known as gonococci (plural), or gonococcus (singular), is a species of Gram-negative coffee bean-shaped diplococci bacteria responsible for the sexually transmitted infection gonorrhea.[1] N. gonorrhoeae was first described by Albert Neisser in 1879.

Microbiology

Neisseria are fastidious Gram-negative cocci that require nutrient supplementation to grow in laboratory cultures. To be specific, they grow on chocolate agar with carbon dioxide. These cocci are facultatively intracellular and typically appear in pairs (diplococci), in the shape of coffee beans. Of the eleven species of Neisseria that colonize humans, only two are pathogens. N. gonorrhoeae is the causative agent of gonorrhea (also called "The Clap") and is transmitted via sexual contact.[2]

Neisseria is usually isolated on Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and trimethoprim) and nutrients that facilitate the growth of Neisseria species while inhibiting the growth of contaminating bacteria and fungi. Further testing to differentiate the species includes testing for oxidase (all clinically relevant Neisseria show a positive reaction) and the carbohydrates maltose, sucrose, and glucose test in which N. gonorrhoeae will oxidize (that is, utilize) only the glucose.

N. gonorrhoeae are non-motile and possess type IV pili to adhere to surfaces. The type IV pili operate mechanistically similar to a grappling hook. Pili extend and attach to a substrate that signals the pilus to retract, dragging the cell forward. N. gonorrhoeae are able to pull 100,000 times their own weight, and it has been claimed that the pili used to do so are the strongest biological motor known to date, exerting one nanonewton.[3]

N. gonorrhoeae has surface proteins called Opa proteins, which bind to receptors on immune cells. In so doing, N. gonorrhoeae is able to prevent an immune response. The host is also unable to develop an immunological memory against N. gonorrhoeae – which means that future reinfection is possible. N. gonorrhoeae can also evade the immune system through a process called antigenic variation, in which the N. gonorrhoeae bacterium is able to alter the antigenic determinants (sites where antibodies bind) such as the Opa proteins[4] and Type IV pili[5] that adorn its surface. The many permutations of surface proteins make it more difficult for immune cells to recognize N. gonorrhoeae and mount a defense.[6]

N. gonorrhoeae is naturally competent for DNA transformation as well as being capable of conjugation. These processes allow for the DNA of N. gonorrhoeae to acquire or spread new genes. Especially dangerous from the aspect of healthcare is the ability to conjugate, since this can lead to antibiotic resistance.[7]

Genome

The genomes of several strains of N. gonorrhoeae have been sequenced. Most of them are about 2.1 Mb in size and encode 2,100 to 2,600 proteins (although most seem to be in the lower range).[9] For instance, strain NCCP11945 consists of one circular chromosome (2,232,025 bp) encoding 2,662 predicted ORFs and one plasmid (4,153 bp) encoding 12 predicted ORFs. The estimated coding density over the entire genome is 87%, and the average G+C content is 52.4%, values that are similar to those of strain FA1090. The NCCP11945 genome encodes 54 tRNAs and four copies of 16S-23S-5S rRNA operons.[10]

In 2011, researchers at Northwestern University found evidence of a human DNA fragment in a Neisseria gonorrhoeae genome, the first example of horizontal gene transfer from humans to a bacterial pathogen.[11][12]

Transmission

N. gonorrhoeae is transmitted from person to person during sexual relations. Traditionally, the bacteria was thought to move attached to spermatozoon, but this hypothesis did not explain female to male transmission of the disease. A recent study suggests that rather than “surf” on wiggling sperm, N. gonorrhoeae bacteria uses hairlike structures called pili to anchor onto proteins in the sperm and move through coital liquid.[13]

Survival of gonococci

The exudates from infected individuals contain many polymorphonuclear leukocytes (PMN) with ingested gonococci. These gonococci stimulate the PMN to release an internal oxidative burst involving reactive oxygen species in order to kill the gonococci.[14] However, a significant fraction of the gonococci can resist killing and are able to reproduce within the PMN phagosomes.

Stohl and Seifert showed that the bacterial RecA protein, that mediates recombinational repair of DNA damage, plays an important role in gonococcal survival.[15] The protection afforded by RecA protein may be linked to transformation, the process by which recipient gonococci take up DNA from neighboring gonococci and integrate this DNA into the recipient genome through recombination. Michod et al. have suggested that an important benefit of transformation in N. gonorrhoeae may be recombinational repair of oxidative DNA damages caused by oxidative attack by the hosts phagocytic cells.[16]

Gallery

References

  1. Ryan, KJ; Ray, CG, eds. (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. ISBN 0-8385-8529-9.
  2. Genco, C; Wetzler, L, eds. (2010). Neisseria: Molecular Mechanisms of Pathogenesis. Caister Academic Press. ISBN 978-1-904455-51-6.
  3. Biais N, Ladoux B, Higashi D, So M, Sheetz M (2008). "Cooperative retraction of bundled type IV pili enables nanonewton force generation". PLoS Biol. 6 (4): e87. doi:10.1371/journal.pbio.0060087. PMC 2292754. PMID 18416602. Lay summaryNew Scientist (19 April 2008).
  4. Stern, Anne; Brown, Melissa; Nickel, Peter; Meyer, Thomas F. (1986). "Opacity genes in Neisseria gonorrhoeae: Control of phase and antigenic variation". Cell. 47 (1): 61–71. doi:10.1016/0092-8674(86)90366-1. PMID 3093085.
  5. Cahoon, Laty A.; Seifert, H. Steven (2011). "Focusing homologous recombination: Pilin antigenic variation in the pathogenic Neisseria". Molecular Microbiology. 81 (5): 1136–43. doi:10.1111/j.1365-2958.2011.07773.x. PMID 21812841.
  6. STI Awareness: Gonorrhea. Planned Parenthood Advocates of Arizona. 11 April 2011. Retrieved 31 August 2011.
  7. Aas, Finn Erik; Wolfgang, Matthew; Frye, Stephan; Dunham, Steven; Løvold, Cecilia; Koomey, Michael (2002). "Competence for natural transformation in Neisseria gonorrhoeae: Components of DNA binding and uptake linked to type IV pilus expression". Molecular Microbiology. 46 (3): 749–60. doi:10.1046/j.1365-2958.2002.03193.x. PMID 12410832.
  8. http://picasaweb.google.com/mcmumbi/USMLEIIImages
  9. Neisseria gonorrhoeae genome statistics, Broad Institute
  10. PMID 18586945 (PMID 18586945)
    Citation will be completed automatically in a few minutes. Jump the queue or expand by hand
  11. Anderson, Mark T.; Seifert, H. Steven (2014). "Neisseria gonorrhoeae and humans perform an evolutionary LINE dance". Mobile Genetic Elements. 1 (1): 85–87. doi:10.4161/mge.1.1.15868. PMC 3190277. PMID 22016852. Lay summaryScienceDaily (February 14, 2011).
  12. Anderson, M. T.; Seifert, H. S. (2011). "Opportunity and Means: Horizontal Gene Transfer from the Human Host to a Bacterial Pathogen". MBio. 2 (1): e00005–11. doi:10.1128/mBio.00005-11. PMC 3042738. PMID 21325040.
  13. Anderson, M. T.; Dewenter, L.; Maier, B.; Seifert, H. S. (2014). "Seminal Plasma Initiates a Neisseria gonorrhoeae Transmission State". MBio. 5 (2): e01004–13. doi:10.1128/mBio.01004-13. PMID 24595372.
  14. Simons, M. P.; Nauseef, W. M.; Apicella, M. A. (2005). "Interactions of Neisseria gonorrhoeae with Adherent Polymorphonuclear Leukocytes". Infection and Immunity. 73 (4): 1971–7. doi:10.1128/iai.73.4.1971-1977.2005. PMC 1087443. PMID 15784537.
  15. Stohl, E. A.; Seifert, H. S. (2006). "Neisseria gonorrhoeae DNA Recombination and Repair Enzymes Protect against Oxidative Damage Caused by Hydrogen Peroxide". Journal of Bacteriology. 188 (21): 7645–51. doi:10.1128/JB.00801-06. PMC 1636252. PMID 16936020.
  16. Michod, Richard E.; Bernstein, Harris; Nedelcu, Aurora M. (2008). "Adaptive value of sex in microbial pathogens". Infection, Genetics and Evolution. 8 (3): 267–85. doi:10.1016/j.meegid.2008.01.002. PMID 18295550.
  17. 17.0 17.1 17.2 "Public Health Image Library (PHIL)".