Vibrio cholerae - Revision history

Aidan: /* Microbiology */

2022-07-06T02:05:46Z

Microbiology

← Older revision		Revision as of 02:05, 6 July 2022
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	===Microbiology===		===Microbiology===

	*~~[[Shape::~~Curved]], motile [[Stain::Gram-negative]] [[Shape::bacillus]] within the class [[Class::Gammaproteobacteria]], family [[Family::Vibrionaceae]], and genus [[Genus::Vibrio]]		*Curved, motile [[Stain::Gram-negative]] [[Shape::bacillus]] within the class [[Class::Gammaproteobacteria]], family [[Family::Vibrionaceae]], and genus [[Genus::Vibrio]]
	*Oxidase [[Oxidase::positive]] and facultatively anaerobic		*Oxidase [[Oxidase::positive]] and facultatively anaerobic
	*Serotypes differ in O-specific polysaccharide (OSP) chains of lipopolysaccharide (LPS), and are grouped into more than 200 serogroups		*Serotypes differ in O-specific polysaccharide (OSP) chains of lipopolysaccharide (LPS), and are grouped into more than 200 serogroups

Aidan at 14:29, 19 November 2020

2020-11-19T14:29:02Z

← Older revision		Revision as of 14:29, 19 November 2020
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	*Ingestion of contaminated water leads to small intestine colonization mediated by TCP (toxin coregulated pili)		*Ingestion of contaminated water leads to small intestine colonization mediated by TCP (toxin coregulated pili)
	*''Vibrio'' is non-invasive but rather causes toxin-mediated disease		*''Vibrio'' is non-invasive but rather causes toxin-mediated disease
			*VP1 pathogenic island is associated with pandemic strains of cholera and confers severity
	*Severe secratory diarrhea cause by the virulence factor cholera toxin (CT)		*Severe secratory diarrhea cause by the virulence factor cholera toxin (CT)
	**CT causes severe secretory diarrhea		**CT causes severe secretory diarrhea
			**CT comprises 1 A subunit and 5 B subunits
	**It enters epithelial cells by binding to a glycosphingolipid, GM1		**It enters epithelial cells by binding of B subunit to a glycosphingolipid, GM1
	**Inside the cell, it increases activity of adenylyl cyclase, causing an increase in cAMP, which causes chloride ion secretion		**Inside the cell, it increases activity of adenylyl cyclase, causing an increase in cAMP, which causes chloride ion secretion
	**CT is encoded by ctxAB genes, which were added to TCP-positive ''V. cholera'' by a bacteriophage		**CT is encoded by ctxAB genes, which were added to TCP-positive ''V. cholera'' by a bacteriophage
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	===Epidemiology===		===Epidemiology===

			*Fecal-oral transmission, with humans being only known host
			**Survives in brackish water
	*3-5 million people affected annually		*3-5 million people affected annually
	*100-120,000 deaths annually, but likely underestimated		*100-120,000 deaths annually, but likely underestimated
	*Human are only known hosts
	*Typically in poor countries with poor sanitation		*Typically in poor countries with poor sanitation
	*Seven pandemics described since 1817		*Seven pandemics described since 1817
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	*Incubation period [[Usual incubation period::6 hours to 5 days\|Usual incubation period::2 hours to 5 days]], depending on the size of the inoculum		*Incubation period [[Usual incubation period::6 hours to 5 days\|Usual incubation period::2 hours to 5 days]], depending on the size of the inoculum
	*Profuse painless watery diarrhea with rice-water stools, up to 1 L/h		*Profuse painless watery diarrhea with rice-water stools, up to 1 L/h when severe
	*~~Abdo~~ cramping and nausea		*Abdominal cramping and nausea
	*Only rarely associated with fever, as it is non-invasive		*Only rarely associated with fever, as it is non-invasive
	**More likely to be hypothermic from severe dehydration		**More likely to be hypothermic from severe dehydration
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	*Severe, life threatening dehydration occurs in 10-20%		*Severe, life threatening dehydration occurs in 10-20%
	**Profuse diarrhea, leading to shock from profound fluid losses, and, eventually, death		**Profuse diarrhea, leading to shock from profound fluid losses, and, eventually, death
			**Up to 1 L of diarrhea per day, with death occurring in as little as one day
	*Signs are those of severe dehydration:		*Signs are those of severe dehydration:
	**Lethargy or loss of consciousness		**Lethargy or loss of consciousness
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	**Low blood pressure and weak pulse		**Low blood pressure and weak pulse
	**Unable to drink		**Unable to drink
			*Can see significant electrolyte abnormalities due to the secretory diarrhea

			=== Cholera Sicca ===

			* Fluid builds up in abdomen and can cause dehydration and death even without significant bowel movements

	===Asymptomatic Carriage===		===Asymptomatic Carriage===
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	*Colonized patients are asymptomatic but still infectious		*Colonized patients are asymptomatic but still infectious
	*Among those who are symptomatic, they can shed it for months after illness (though most stop 2-3 days after symptom resolution)		*Among those who are symptomatic, they can shed it for months after illness (though most stop 2-3 days after symptom resolution)

			== Differential Diagnosis ==

			* Refer to [[diarrhea in the returned traveller]]

	==Diagnosis==		==Diagnosis==
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	*Can use a cholera cot		*Can use a cholera cot

	===~~Choice of~~ Fluids===		===Rehydration Fluids===

	*D5/lactated Ringer's (D5LR) is the preferred IV fluid, though D5-NS can be used if D5LR is not available		*D5/lactated Ringer's (D5LR) is the preferred IV fluid, though D5-NS can be used if D5LR is not available
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	*Improved water hygiene and sanitation is the backbone of long-term prevention, but is expensive and slow to set up		*Improved water hygiene and sanitation is the backbone of long-term prevention, but is expensive and slow to set up

	=== Infection Prevention and Control ===		===Infection Prevention and Control===

	* Routine precautions		*Routine precautions
	* Needs contact precaution if:		*Needs contact precaution if:
	** Pediatric patient		**Pediatric patient
	** Incontinent		**Incontinent
	** Stool not contained		**Stool not contained
	** Poor hygiene		**Poor hygiene
	** Patient is contaminating the environment		**Patient is contaminating the environment
	* Continue until 48 hours after symptoms have resolved		*Continue until 48 hours after symptoms have resolved

	===Immunization===		===Immunization===

Aidan at 00:36, 19 November 2020

2020-11-19T00:36:30Z

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	== Background ==		==Background==

	*Causes '''cholera''', a severe diarrheal illness that is transmitted with the fecal-oral route (food or water), and specifically associated with improper sanitation		*Causes '''cholera''', a severe diarrheal illness that is transmitted with the fecal-oral route (food or water), and specifically associated with improper sanitation
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	**In an emergency, can add 1/2 tsp salt with 6 tsp sugar in 1 L of clean water		**In an emergency, can add 1/2 tsp salt with 6 tsp sugar in 1 L of clean water

	== Prevention ==		==Prevention==

	* Improved water hygiene and sanitation is the backbone of long-term prevention, but is expensive and slow to set up		*Improved water hygiene and sanitation is the backbone of long-term prevention, but is expensive and slow to set up

			=== Infection Prevention and Control ===

			* Routine precautions
			* Needs contact precaution if:
			** Pediatric patient
			** Incontinent
			** Stool not contained
			** Poor hygiene
			** Patient is contaminating the environment
			* Continue until 48 hours after symptoms have resolved

	===Immunization===		===Immunization===

Aidan at 00:30, 19 November 2020

2020-11-19T00:30:57Z

Show changes

Aidan: Text replacement - "== Presentation" to "== Clinical Manifestations"

2020-08-02T10:47:02Z

Text replacement - "== Presentation" to "== Clinical Manifestations"

← Older revision		Revision as of 10:47, 2 August 2020
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	* In newly affected countries, everyone is at risk		* In newly affected countries, everyone is at risk

	== ~~Presentation~~ ==		== Clinical Manifestations ==

	=== Cholera ===		=== Cholera ===

Aidan at 11:59, 16 August 2019

2019-08-16T11:59:42Z

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	* [http://www.cotsprogram.com/ Cholera Outbreak Training and Shigellosis (COTS) Program]: information and tools for managing cholera		* [http://www.cotsprogram.com/ Cholera Outbreak Training and Shigellosis (COTS) Program]: information and tools for managing cholera

			{{DISPLAYTITLE:''Vibrio cholerae''}}
	[[Category:Gram-negative bacilli]]		[[Category:Gram-negative bacilli]]

Aidan at 11:59, 16 August 2019

2019-08-16T11:59:27Z

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		⚫	* Causes '''cholera''', a severe diarrheal illness that is transmitted with the fecal-oral route (food or water), and specifically associated with improper sanitation
	= Vibrio cholerae =

⚫	* ~~Severe~~ ~~diarrheal~~ ~~illness~~ ~~caused~~ by ~~Vibrio~~ ~~cholerae~~ transmitted with the fecal-oral route (food or water), and specifically associated with improper sanitation

	== Microbiology ==		== Microbiology ==
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	* [http://www.cotsprogram.com/ Cholera Outbreak Training and Shigellosis (COTS) Program]: information and tools for managing cholera		* [http://www.cotsprogram.com/ Cholera Outbreak Training and Shigellosis (COTS) Program]: information and tools for managing cholera

			[[Category:Gram-negative bacilli]]

Aidan: Aidan moved page Vibrio to Vibrio cholerae

2019-08-16T11:58:03Z

Aidan moved page Vibrio to Vibrio cholerae

← Older revision		Revision as of 11:58, 16 August 2019
(No difference)

Maintenance script: Imported from text file

2019-08-11T17:58:26Z

Imported from text file

New page

= Vibrio cholerae =

* Severe diarrheal illness caused by Vibrio cholerae transmitted with the fecal-oral route (food or water), and specifically associated with improper sanitation

== Microbiology ==

* Curved, motile Gram-negative bacillus
* Serogroups O1 and O139 cause epidemic cholera, others cause mild gastroenteritis

== Pathogenesis ==

* Can grow in salt water with organic material
* Human are only known hosts
* Ingestion of contaminated water leads to small intestine colonization mediated by TCP (toxin coregulated pili)
** ''Vibrio'' is non-invasive
* Severe secratory diarrhea cause by cholera toxin (CT)
** CT causes severe secretory diarrhea
** It enters epithelial cells by binding to a glycosphingolipid, GM1
** Inside the cell, it increases activity of adenylyl cyclase, causing an increase in cAMP, which causes chloride ion secretion
** CT is encoded by ctxAB genes, which were added to TCP-positive ''V. cholera'' by a bacteriophage

== Epidemiology ==

* 3-5 million people affected annually
* 100-120,000 deaths annually, but likely underestimated
* Typically in poor countries with poor sanitation
* Seven pandemics described since 1817
** The seventh and current pandemic started in Indonesia in 1961, and is currently still circulating
*** The current strain is called El Tor

== Risk Factors ==

* Limited access to clean water and sanitation
* In endemic countries, Very young less than four
* In newly affected countries, everyone is at risk

== Presentation ==

=== Cholera ===

* 6h to 5d onset requiring very low innoculum
* Profuse painless watery diarrhea with rice-water stools
** Up to 1 L/h
* Abdo cramping and nausea
* Only rarely associated with fever, as it is non-invasive
** More likely to be hypothermic from severe dehydration

=== Severe cholera (cholera gravis) ===

* Severe, life threatening dehydration occurs in 10-20%
** Profuse diarrhea, leading to shock from profound fluid losses, and, eventually, death
* Signs are those of severe dehydration:
** Lethargy or loss of consciousness
** Sunken eyes
** Low skin turgor
** Low blood pressure and weak pulse
** Unable to drink

=== Asymptomatic carriage ===

* 90% of colonized patients are asymptomatic but still infectious [CITATION NEEDED]
* Among those who are symptomatic, they can shed it for months after illness (though most stop 2-3 days after symptom resolution)

== Diagnosis ==

* Usually clinical diagnosis in low-resource settings
* Stool culture
** Helpful for determining resistance during outbreaks, but not routinely done
* Rapid stool tests, requiring dark field microscopy to see "shooting star" appearance of vibrios
* Serology, sometimes

== Treatment ==

* Isolation
* Rehydration is the main way to reduce mortality
** Mild: alert with normal exam
*** Oral rehydration at home, guided by thirst
*** Should be observed until they are reliably replacing their losses, then can be discharged home
** Moderate: alert to restless, with some abnormalities on exam to suggest dehydration
*** Oral or IV rehydration in hospital
*** Bolus 75 mL/kg over 3-4 hours
*** Replace losses
*** Observe until signs of dehydration resolves and patient peeing
** Severe: cholera gravis, as described above
*** Aggressive IV rehydration in hospital
*** Bolus >100 mL/kg as rapidly as possible until circulation is restored, then the remainder over 3 hours
*** Replace losses
* Replace electrolytes as needed, but laboratory assistance is not required in most cases
* Antibiotics decrease duration and volume of diarrhea, and are indicated in cases of moderate or severe cholera
** Doxycycline 300 mg po once, avoided in pregnant women and children <8 years
** Azithromycin 1 g po once
** Ciprofloxcin used previously, but increasing resistance
* Avoid antiemetics and antimotility agents
* Consider zinc supplementation in children 10-30 mg daily x5-7 days
* Can use a cholera cot

=== Choice of fluids ===

* D5/lactated Ringer's (D5LR) is the preferred IV fluid, though D5-NS can be used if D5LR is not available
** "Dhaka solution" has more potassium, bicarbonate, and glucose, and is optimal
* NS can be used for circulatory support
* Oral rehydration solutions (ORS) have salt and glucose
** In an emergency, can add 1/2 tsp salt with 6 tsp sugar in 1 L of clean water

== Vaccination ==

* Dukoral and Shanchol are both killed ''Vibrio'' vaccines
* Immunity lasts 6 months to a few years, not approved in children
** Boosters every 2 years
* Both vaccines are well-tolerated but only 60-80% effective
* During outbreaks, they have about 80% effectiveness

== Prognosis ==

* Depends on context (rich vs poor)

== Further Reading ==

* [http://www.cotsprogram.com/ Cholera Outbreak Training and Shigellosis (COTS) Program]: information and tools for managing cholera