Spirochaetes Introduction And Lab Diagnosis, Assignments of Microbiology

Download Spirochaetes Introduction And Lab Diagnosis and more Assignments Microbiology in PDF only on Docsity!

SPIROCHAETES

By Suhar Achar

INTRODUCTION

• (^) Member of the phylum Spirochaetes which contains distinctive diderm (double-membrane) bacteria.
• (^) Spirochaetes are distinguished from other bacterial phyla by the location of their flagella, sometimes called axial filaments , which run lengthwise between the bacterial inner membrane and outer membrane in periplasmic space. These cause a twisting motion which allows the spirochaete to move about.

PATHOGENICITY

• (^) Many organisms within the Spirochaetes phylum cause prevalent diseases. Pathogenic members of this phylum include the following:
• (^) Leptospira species , which causes leptospirosis.
• (^) Borrelia burgdorferi , B. garinii , and B. afzelii , which cause Lyme disease
• (^) Borrelia recurrentis , which causes relapsing fever
• (^) Treponema pallidum subspecies which cause treponematoses such as syphilis and yaws.
• (^) Brachyspira pilosicoli and Brachyspira aalborgi , which cause Intestinal spirochaetosis

• (^) Spirochetes may also cause dementia and may be involved in the pathogenesis of Alzheimer's disease. Salvarsan , the first partially organic synthetic antimicrobial drug in medical history, was effective against spirochetes only and was primarily used to cure syphilis.
• (^) Treponema includes the agents of syphilis ( T. pallidum pallidum ) and yaws ( T. pallidum pertenue ). Borrelia includes several species transmitted by lice and ticks and causing relapsing fever ( B. recurrentis and others) and Lyme disease ( B. burgdorferi ) in humans. Spirochaeta are free-living nonpathogenic inhabitants of mud and water, typically thriving in anaerobic (oxygen-deprived) environments. Leptospirosis , caused by Leptospira , is principally a disease of domestic and wild mammals and is a secondary infection of humans.

WARTHIN–STARRY STAIN

• (^) The Warthin–Starry stain ( WS ) is a silver nitrate-based staining method (a silver stain) used in histology. It was first introduced in 1920 by American pathologists Aldred Scott Warthin (1866-1931) and Allen Chronister Starry (1890- 1973), for the detection of spirochetes. It has been considered a standard stain for the detection of spirochetes, and is also used to stain Helicobacter pylori , Lawsonia intracellularis, Microsporidia , and particulates. It is also important for confirmation of Bartonella henselae , a causative organism in cat-scratch disease.
• (^) Warthin–Starry stains organisms dark brown to black, and the

HELICOBACTER PYLORI COLONIZED ON THE SURFACE OF REGENERATIVE EPITHELIUM, STAINED WITH THE WARTHIN- STARRY METHOD.

PRINCIPLE

• (^) This technique involves the argyrophilic reaction. The spirochetes are argyrophilic, which means they will absorb silver from a silver solution, but need a separate reducing agent in a solution to reduce the adsorbed silver to visible metallic silver.
• (^) The stain demonstrates black spirochetes against a yellow to pale brown background.

REQUIREMENT

1.Acetate buffer, pH 3. sodium acetate = 4.1 gm acetic acid = 6.25 gm distilled water = 500 gm 2.1% silver nitrate solution in pH 3. acetate buffer 2.Developer solution 2% silver nitrate = 15 ml 5% gelatin solution = 3.75 ml 15% hydroquinone = 12 ml

4.Remove slides from silver solution. Do not rinse.

• (^) Place slides horizontally on a slide rack and cover with developer.
• (^) Allow sections to develop until they are light yellow to golden brown, approximately 1 minute or less. 5.Wash quickly and thoroughly on hot tap water. 6.Rinse in distilled water. 7.Dehydrate, clear and mount.

RESULTS AND

INTERPRETATION

• (^) Spirochetes : black Helicobacter pylori : black Klebsiella : brown/black Nuclei : brown Background : golden yellow

IDENTIFICATION OF SPIROCHETES BY WARTHIN-STARRY STAINING (×1,000). ARROW INDICATES THE TREPREPONEMA PALLIDUM

H. PYLORI COLONIZATION IN GALLBLADDER MUCOSA WITH RESPECT TO GASTRIC MUCOSA COLONIZATION.