Leptospira,an overview

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 25-30oC 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 is usually asymptomatic in them . Contaminated water with urine of infected carrier animals enters to the human body through cuts and abrasions. It can also enter through conjunctiva.

Clinical features

Fever-irregular

Vomiting

Headache

Intense injection of eyes

Purpuric hemorrhage-skin

Albuminuria

Meningitis

Hepatorenal damage

Weil’s disease

Occupational risk to agricultural works, miners, sewer cleaners

Lab diagnosis

Includes examination of blood and urine by microscopic, culture, animal inoculation and serological methods

Prophylaxis includes rodent control, disinfection of water, vaccination of pet animals,  using of  protective wearing.

Treatment

Penicillin

Doxycycline 200mg

 

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