Vibrio

History:

During the 19th century ,cholera spread across the world wide.The current pandemic started in South Asian in  1961 after reached Africa in 1971and the America's in 1991.

Scientific classification

             Domain:Bacteria

                     Phylum:pseudomonadota

                             Class:Gammproteobacteria

                                      Order:vibrionales

                                          Family:vibrionaceae

                                                  Genum:vibrio

Morphology:

* vibrio is a genus of gram negative curved bacilli.

*They are actively motile by means of polar flagellum.

*The name vibrio is derived from its characteristics vibratory motility                                        

(From vibrare meaning 'to vibrate')

* vibrios are present in marine environments and surface waters worldwide.

*The most important member of the genus is vibrio cholerae.

* The vibrio cholerae is a short curved rods,about 1.5×0.2_0.4MU m.

*pleomorphism is common in old culture.

*In stained films of mucus flakes taken from acute cholerae cases,the vibrios are seen arranged in parallel rows this is described as a' Fish in a stream' appearance.

Classification:

Based on their requirement of sodium chloride, vibrios are classified as halophilic and non- halophilic .

*Halophilic: v.parahemolyticus ,v.alginolyticus,v.vulnificus.

*Non-halophilic: vibrio cholerae

Resistance:

* vibrio cholera are susceptible to heat,drying and acids but resist high alkalinity.

*They are killed at 55° c in 15 minutes.

*In clean tap water they survive for thirty days .

* In untreated soil,they may survive for several days.

* On fruits, they survive for 1-5 days at room temperature and for a week in the refrigerator.

*vibrio cholera killed in gastric juice with in few minutes.

Symptoms:

* high fever

* weight loss

*feeling of nausea

* bloating in the belly

*blood pressure becomes low

Adapted from: public health notes.com

Pathogenesis:

* The vibrio cholera remain in the gut and does not multiply  into the blood stream.

*It adheres to the mucosa of the small intestines by both outer membrane protein and flagella adhesions.

*vibrio cholera produces enterotoxin that causes excessive fluid and electrolyte loss.

*sodium chloride aborsorption is inhibited and therefore excreted resulting in water ,sodium chloride and potassium bicarbonate loss.

Lab diagnosis:

Specimen collection and transport

* Stool specimens suspected of containing vibrio species should be collected and transported only in the cairy Blair medium.

*Buffered glycerol medium is not acceptable because in vibrio glycerol is toxic.

*Feces is preferable ,but rectal swabs are acceptable during the acute phase of diarrheal illness.

Direct Detection Method

*vibrio cholera toxin can be detected in stool using an enzyme linked assay (ELISA)or latex agglutination test.

* when stool specimens are examined using a dark field microscopy , the bacilli exhibit characteristics rapid darting ( or) shooting star motility

Treatment:

* Rehydration

            - IV lactated Ringer's ( L R)

             -ORS : by mouth (or) by N G tube

             -Zinc supplement

* Antibiotics

              Adults : Deoxycycline 300 mg PO×1

              Children or pregnant women: TMP-SMX ×3 days

Adapted from: Hind pharma

Prevention:

*Drink boiled water.

* Avoid consumption of raw foods.

*Avoid dairy products as much as possible .

*Wash your hands with soap.

* Wash fruits and vegetables before you eat.

* Drink plenty of water.

References :

1. Ananthanarayan and Paniker's textbook of microbiology

 2.vibrio A presentation by Dr ALPANA VERMA  International medical and Technological University, Tanzania

3.cholera By JAMES NYIRENDA