Source: http://onlinepdfcatalog.com/l/lf.upol.cz1.html
Timestamp: 2019-04-20 04:30:30+00:00

Document:
all widely distributed in nature.
l Among common pathogenic vibrio species belong: – V. cholerae, V. parahaemolyticus, V. vulnificus, V. alginolyticus, V. mimicus.
– 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.
l V. cholerae serotype O1 causes cholera in humans, while other vibrios may cause sepsis, enteritis and other infections.
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.
l Cholera vibrios are motile with a single polar flagellum. Their motility is extremely rapid.
– Humans are one of the reservoirs of this – It is also often found in the aquatic environment and is part of the normal flora of brackish water. – It is often associated with algal blooms (plankton), which are influenced by the water temperature.
l V. cholerae can grow aerobically or anaerobically on a l Vibrios grow at a very high pH (8.5 to 9.5) and are rapidly 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 l Vibrios grow well on thiosulfate-citrate-bile-sucrose (TCBS) agar on which they form yellow colonies.
l Vibrios are oxidase-positive, which differentiates them from enteric gramnegative bacteria grown on blood agar.
– 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.
– all the properties has just opposited as given above.
l Many cholera vibrios share a single heat-labile flagellar H antigen. Antibodies to the H antigen are probably not involved in the protection of susceptible host organisms.
l V. cholerae has cell wall lipopolysaccharides that confer serological specifity as somatic O antigens. There are more than 140 antigens.
l V. cholerae strains causing classical epidemic cholera belong into the O1 group. They are classified as V. cholerae O1. l Strains of other serogroups are classified as V. cholerae non O1 or non-agglutinated vibrios s.c. NAG vibrios (they do not agglutinate in anti-O1 serum) or non-cholera vibrios s.c. NCV. Many of these vibrios may cause diarrhea in humans as s.c. cholera-like disease or gastroenteritis of travellers.
– it has only a negligible significance as a virulence factor.
– it is a main factor of pathogenity,– it is heat-labile protein which can be changed by formol into – synthesis of cholera toxin is controlled by chromosomal gene. Its molecule is a complex of multiple polypeptide chains organized into a toxic unit A, consisting of A1 and A2 subunits, and unit B.
l The B unit mediates tight binding to a cell wall ganglioside of enterocytes in the small intestine. It means 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.
l V. cholerae is pathogenic only for humans. Cholera is not an invasive infection. The microorganism do not reach the blood stream but remain within the intestinal tract.
l Although cholera toxin is the most important virulence factor, the motility and the production of mucinase and other proteolytic enzymes contribute to the ability of V. cholerae to colonize. l The microorganism can colonize the entire intestinal tract from the jejunum to the colon and can multiply to high numbers. An alkaline environment is ideal for bacterial growth.
l In the treatment of cholera absolute priority must be given to the replacement of fluid and electrolytes.
l Antimicrobial therapy shortens the duration diarrhea and reduces the period of excretion ofV. cholerae in the stools of cholera patients.
– tetracyclines have been used most frequently (tetracycline for 3 days), although chloramphenicol, fluoroquinolones,cotrimoxazole and others have also been effective.
– Epidemic cholera is spread primarly by contaminated water and food, most commonly during the warmmonths of the year. Cholera vibrios can be transmittedby direct contact with patients and carrriers.
– About 50% in classical V. cholerae,– only 1% in V. cholerae El tor.
– Aeromonas hydrophila is the most important species from this genus causing disease in humans.
– The strains have been associated with diarrhea.
– Plesiomonas sp. is most common in tropical and – 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 Characteristics of Plesiomonas spp.
l Campylobacter jejuni has emerged as a common human pathogen, causing mainly enteritis and occasionally systemic invasion.
l Helicobacter pylori is associated with antral gastritis and apears to be important in the pathogenesis of ulcer disease.
– Combination of two of the following three antibiotics (amoxicillin, clarithromycin, metronidazole, tetracycline) plus omeprazole.

References: V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V. 
 V.