Brucella: Difference between revisions

Brucella
	;
Scientific classification
Kingdom:	Bacteria;
Phylum:	Proteobacteria;
Class:	Alpha Proteobacteria;
Order:	Rhizobiales;
Family:	Brucellaceae;
Genus:	Brucella;
Species
	B. abortus; B. canis; B. melitensis; B. neotomae; B. ovis; B. suis;

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Revision as of 16:17, 19 January 2017

This page is about microbiologic aspects of the organism(s). For clinical aspects of the disease, see brucellosis.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Danitza Lukac, Vishal Devarkonda, M.B.B.S [2]

Overview

Human brucellosis is caused by four Brucellae species: B. abortus, B. canis, B. melitensis, and B. suis.^[1]

Causes

Brucella is a genus of Gram-negative bacteria.^[2] They are small (0.5 to 0.7 by 0.6 to 1.5 µm), non-motile, encapsulated coccobacilli.
Brucella is the cause of brucellosis, a true zoonotic disease (i.e. human-to-human transmission has not been identified).^[2]
It is transmitted by ingesting infected food, direct contact with an infected animal, or inhalation of aerosols.
Minimum infectious exposure is between 10 - 100 organisms.
Brucellosis primarily occurs through occupational exposure (e.g. exposure to cattle, sheep, pigs), but also by consumption of unpasteurised milk products.
Four species infect humans: B. abortus, B. canis, B. melitensis, and B. suis.
- B. abortus, is less virulent than B. melitensis and is primarily a disease of cattle.
- B. canis affects dogs.
- B. melitensis is the most virulent and invasive species; it usually infects goats and occasionally sheep.
- B. suis is of intermediate virulence and chiefly infects pigs.

Brucella species

Brucella species have been found primarily in mammals. ^[1]^[3] Brucellla species, with their host and degree of virulence is described below:


Species	Host	Human Virulence
B. melitensis	Goats, sheep	++++
B. abortus	Cattle	++/+++
B. canis	Dogs	+
B. suis	Pigs	+
B. ovis	Sheep	-
B. neotomae	Desert woodrat	-
B. pinnipedialis	Seal	+
B. ceti	Dolphin, porpoise, whale	+
B. microti	Common vole	N/A
B. inopinata	Unknown	N/A
Brucella sp. NVSL 07-0026	Baboon	N/A

Tests to differentiate brucella species

Oxidase and catalase tests are positive for most members of the genus Brucella.^[1] Following tests may be used to differentiate between the different species of brucella.


Test	B. melitensis	B. abortus	B. suis	B. neotomae	B. ovis	B. canis
Need to CO2	-	+	-	-	+	-
Production of H2S	-	+	+	+	-	-
Growth on basic fushin 0.002%	+	+	-	-	+	-
Growth on thionin 0.004%	-	-	+	-	+	+
Growth on thionin 0.002%	+	-	+	+	+	+
Destroy with Tb phage	-	+	-	-	-	-

References

↑ ^1.0 ^1.1 ^1.2 Brucella. Wikipedia. https://en.wikipedia.org/wiki/Brucella#Characteristics. Accessed on February 2, 2016
↑ ^2.0 ^2.1 Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.
↑ Pappas G, Akritidis N, Bosilkovski M, Tsianos E (2005). "Brucellosis". N Engl J Med. 352 (22): 2325–36. doi:10.1056/NEJMra050570. PMID 15930423.

[aba-1] 1.0 ^1.1 ^1.2 Brucella. Wikipedia. https://en.wikipedia.org/wiki/Brucella#Characteristics. Accessed on February 2, 2016

[Sherris-2] 2.0 ^2.1 Ryan KJ, Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed. ed.). McGraw Hill. ISBN 0-8385-8529-9.

[pmid15930423-3] Pappas G, Akritidis N, Bosilkovski M, Tsianos E (2005). "Brucellosis". N Engl J Med. 352 (22): 2325–36. doi:10.1056/NEJMra050570. PMID 15930423.

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[2]

[3]

@@ Line 26: / Line 26: @@
 Human brucellosis is caused by four [[Brucella|Brucellae]] species: [[Brucella abortus|''B. abortus'']], [[Brucella canis|''B. canis'']], [[Brucella melitensis|''B. melitensis'']], and ''B. suis''.<ref name="aba">Brucella. Wikipedia. https://en.wikipedia.org/wiki/Brucella#Characteristics. Accessed on February 2, 2016</ref>
-==Causes==
+===Causes===
 *'''''[[Brucella]]''''' is a genus of Gram-negative bacteria.<ref name="Sherris">{{cite book | author = Ryan KJ, Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | isbn = 0-8385-8529-9 }}</ref> They are small (0.5 to 0.7 by 0.6 to 1.5 µm), non-motile, encapsulated coccobacilli.
 *''[[Brucella]]'' is the cause of brucellosis, a true zoonotic disease (i.e. human-to-human transmission has not been identified).<ref name="Sherris" />
@@ Line 38: / Line 38: @@
 **''B. suis'' is of intermediate virulence and chiefly infects pigs.
-''[[Brucella]]'' species have been found primarily in mammals:
+=== Brucella species ===
+''[[Brucella]]'' species have been found primarily in mammals. <ref name="aba" /><ref name="pmid15930423">{{cite journal| author=Pappas G, Akritidis N, Bosilkovski M, Tsianos E| title=Brucellosis. | journal=N Engl J Med | year= 2005 | volume= 352 | issue= 22 | pages= 2325-36 | pmid=15930423 | doi=10.1056/NEJMra050570 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15930423  }} </ref> Brucellla species, with their host and degree of virulence is described below:
 {| style="border: 0px; font-size: 90%; margin: 3px;" align="center"
-|+ '''Brucellae Species, Host and Human Virulente'''<ref name="aba">Brucella. Wikipedia. https://en.wikipedia.org/wiki/Brucella#Characteristics. Accessed on February 2, 2016</ref><ref name="pmid15930423">{{cite journal| author=Pappas G, Akritidis N, Bosilkovski M, Tsianos E| title=Brucellosis. | journal=N Engl J Med | year= 2005 | volume= 352 | issue= 22 | pages= 2325-36 | pmid=15930423 | doi=10.1056/NEJMra050570 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15930423  }} </ref>
+|+
 ! style="width: 180px;background: #4479BA" |{{fontcolor|#FFF| Species}}
 ! style="width: 120px;background: #4479BA" |{{fontcolor|#FFF| Host}}
@@ Line 91: / Line 92: @@
 |}
-[[Oxidase test|Oxidase]] and [[Catalase test|catalase tests]] are positive for most members of the genus [[Brucella|''Brucella'']]:
+=== Tests to differentiate brucella species ===
+[[Oxidase test|Oxidase]] and [[Catalase test|catalase tests]] are positive for most members of the genus [[Brucella|''Brucella'']].<ref name="aba" /> Following tests may be used to differentiate between the different species of brucella.
 {| style="border: 0px; font-size: 90%; margin: 3px;" align="center"
-|+ '''Brucellae Species and Host'''<ref name="aba">Brucella. Wikipedia. https://en.wikipedia.org/wiki/Brucella#Characteristics. Accessed on February 2, 2016</ref>
+|+
 ! style="width: 180px;background: #4479BA" |{{fontcolor|#FFF| Test}}
 ! style="width: 120px;background: #4479BA" |{{fontcolor|#FFF| ''B. melitensis'' }}