Elzu's micro notes

Genus leptospira consist both pathogenic and saprophytic species. L. interrogans are medically important species. They are again classified into many serotypes.  Morphological features 6-20 µm length 0.1 µm thickness They are actively motile, Gram negative bacteria ,mainly stained by special stains Giemsa stain and silver impregnation method. They can also seen under dark ground illumination and electron microscopy. Cultural characters Enriched media with rabbit serum, Korthof’s media, Stuarts media, Fletcher’s media are used for cultivation. EMJH media is commonly used. Optimum temperature for incubation is 25-30 o C with a pH of media 7.2-7.5 . Leptospira grows in aerobic or microaerophilic conditions. It can be inoculated into guinea pigs     and also could grow in chorioallantoic membrane of chick embryos. Resistance Leptospira is susceptible to heat ,sensitive to bile acids and disinfectants. Pathogenicity Rats are the natural reservoir, infection...

Helicobacter     pylori Helicobacter pylori  is a spiral bacteria discovered by  two Australian scientists Warren and Marshall in 1983. Today H pylori  colonies the stomach of  half the human population of the world. Usually it infects from early childhood . Helicobacter pylori   is adapted to human gastric mucosa. The presence of helicobacter was detected  even in the intestine of pre Columbian mummies in USA. Helicobacter pylori  was originally named as Campylobacter pylori   but as there was differences from Campylobacter it was renamed as Helicobacter pylori. Morphological characters Helicobacter pylori  is a gram negative spiral  bacteria , motile by lophotrichous  flagella. In old culture it appears  in coccoid form. Biochemical characters It produces oxidase , catalase , phosphatase and hydrogen sulphide. A distinctive property of this bacteria is abundant production of urease. This property is u...