Source: http://chestervetclinic.com/l/lf.upol.cz1.html
Timestamp: 2019-04-25 22:20:23+00:00

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l The genus can be divided: – into non-halophilic vibrios, including V. cholerae, that are able to grow in media without added salt, – and halophilic species which do not grow in these media, they require higher contents of salt.
– V. cholerae serotype O1: epidemic and pandemic cholera – V. cholerae serotype non O1: choleralike diarrhea, mild diarrhea, rarely extraintestinal infection – V. parahaemolyticus: gastroenteritis, possibly extraintestinal – other (V. mimicus, V. vulnificus.): ear, wound, soft tissue and other extraintestinal infections, all uncommon l Gramnegative, slim, curved rods about 2 to 4 mm long. l Cell may be linked end to end, forming "S" shapes and l They are non-spore forming and do not form a capsule.
– Annually 5-7 million cases, 100,000 deaths worldwide.
l V. cholerae can grow aerobically or anaerobically on a variety of simple media.
l Vibrios grow at a very high pH (8.5 to 9.5) and are rapidly killed by acid conditions.
l In alkaline peptone water they produce a turbidity and surface membrane in six hours of incubation.
l V. cholerae grows in convex, smooth, round colonies on nutrient or blood agar.
l Vibrios grow well on thiosulfate-citrate-bile-sucrose (TCBS) agar on which they form yellow colonies.
l V. cholerae strains produce catalase. Vibrios form acids without gas from a many sugars.
l Cholera biotype: – causes severe forms of cholera with a high – does not hemolyse on blood agar,– does not agglutinate chicken, sheep or human – it is susceptible to polymyxin B.
l El tor biotype: – all the properties has just opposited as given above.
l The V. cholerae serogroup O1 antigen has determinants A, B, C that make possible further subdivison into three serologic subtypes: – A,B (s.c. Ogawa) – A,C (s.c. Inaba) – A,B,C (s.c. Hikojima) – it has only a negligible significance as a virulence factor.
l The B unit mediates tight binding to a cell wall ganglioside of enterocytes in the small intestine. It means that ganglioside G serves as the mucosal receptor for subunit B, which promotes entry of subunit A into cell. l Activation of subunit A1 yields increased levels of intracellular cyclic AMP (adenosine monophosphate) and results in prolonged hypersecretion of water and electrolytes. There is increased sodium-dependend chloride secretion, and absorption of sodium and chloride is inhibited. Diarrhea occurs - as much as 20 - 30 L/day -with resulting dehydratation, shock, acidosis and death.
– diarrhea and other (vomiting, pain in the abdominal region, hypotermia, hypotension, anuria, metabolic acidosis and others) l In the treatment of cholera absolute priority must be given to the replacement of fluid and electrolytes.
– Plesiomonas sp. is most common in tropical and subtropial areas. – Plesiomonas shigeloides can cause diarrhea.
Ø Gram-negative facultatively anaerobic bacillusØ Motile species have single polar flagellum (nonmotile species apparently not associated with human disease) Ø 16 phenospecies: Most significant human pathogens A. hydrophila, A. caviae, A. veronii biovar sobria Ø Ubiquitous in fresh and brackish waterØ Acquired by ingestion of or exposure to contaminated water or food Characteristics of Plesiomonas spp.
l It is motile and a strong producer of urease. l It is present on the gastric mucosa of less than 20% of persons under age 30, but increases in prevalence to 40-60% of persons age 60. l In developing countries, the prevalence of infection may be 80% or higher in adults.

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