Spirochetes

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Dr. Harisingh gour central University Sagar
(M.P.)
Structure, function,properties and economic
importance of gram
negative bacteria
Spirochetes gram negative bacteria
Submitted to- Dr. Yogesh Bhargav (Department of
applied microbiology)
Submitted by- Priyanshi mishra, Msc Ist Sem.
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overview

• Introduction,
• General characteristics,
• Taxonomy,
• Structure,
• Kind of stain used,
• Microscopy,
• Disease,
• Test for diagnosis of spirochetes,
• Culture,
• Transmission,
• Economic importance.

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Gram negative bacteria

• Group of bacteria that do not retain the crystal
  violet stain,
• Used in the Gram staining method of bacterial
  Differentiation,
• making positive identification possible.
• They appear pink due to counter-stain.

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Spirochetes Introduction
Greek spira - a coil, Chaeta
hair. Spirochetes are gram negative Eubacteria.
Distinguished from all bacteria by there slender
helical morphology and corkscrew like movement.
This is possible because of endoflagella enclosed
in space between cell and flexible sheath that
surround it. Comprises both aerobic and anaerobic
bacteria that inhibit a wide range of habitat
including water and soil. As well as the gut and
oral cavities of both vertebrates and
invertebrates.
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General Characteristics

• Gram negative,
• Structurally more complex than other bacteria.

• Elongated, motile, flexible
• bacteria twisted spirally
• along the long axis
• are termed spirochetes.

• Contain endoflagella which are along the helical
  protoplasmic cylinder and
• situated between the outer membrane and cell
  wall.
• Replication slow (doubling time 30 hr.).
• Size vary widely, some being as long as 500um
  and other as short as 5um.

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Cont

• Many are free living saprophytes, while some are
  obligate parasites.
• They may be aerobic, anaerobic or facultative.
• Reproduction is by transverse fission.

• Tightly coiled bacteria.

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Taxonomy
Family spirochetes Genus cristispira,
treponema,
borrelia.
Family- leptospiraceae Genus- leptospira
Order spirocheatales
Members of Genus spirocheta are saprophytes
found in water and sewage, while members of
Genus cristispira are found in molluses.

• Human pathogens are found in
• genera
• Treponema,
• Borrelia ,
• Leptospira.

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Treponema
Greek Trepos Turn, Nema Thread.

• Short,
• Slender with fine spirals,
• Pointed or rounded ends,
• Pathogenic,
• Occurs as commensals in mouth, intestines,
• genitalia,
• Identical in morphology,
• Antigenic structure
• The species T. Pallidum is considered to include
• 3 subspecies-
• T. Pallidum causing venereal syphilis,
• Endemicum causing endemic syphilis,
• Pertenue Causing yaws.

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Borrelia

• Large,
• Motile,
• Refractive spirochetes.
• irregular, wide, open coils.
• Usually 5-30um long and 0.3-0.7um wide
• Species of borrelia occurs as commensals on the
  buccal and genital mucosa.

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Leptospira
O
Leptos fine or thin.

• Motile,
• Delicate spirochetes,
• Possessing large number of closely wound
• spirals and characteristics hooked ends,
• Too thin to be seen under light microscope,
• Several Leptospires are Saprophytic and
• many are parasitic in rodents and other
• animals.

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Structure

• The spirochetes cell consists of
• protoplasmic cylinder- surrounded by
• plasma membrane.
• Gram negative type cell wall.
• Two or more than 100 flagella called
• axial fibrils, periplasmic flagella or
• endoflagella are located in periplasm.
• Whole complex of periplasmic flagella
• is called axial filament.
• Axial fibrils and periplasmic cylinder
• surrounded by multilayered but
• flexible outer membrane or outer sheath.
• Contain lipid, protein and
• carbohydrates.

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Staining with special stain"

• Dark field microscopy ??

• Giemsa,
• Fontana stains,
• Morozovstain
• (silver impregnation)

Microscopy

• Flouroscent microscopy ??

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Disease caused by spirochetes"
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Test for diagnosis of spirochetes

• Serological tests
• Venereal disease research laboratory (VDRL
  test),
• Treponema pallidum haemagglutination (TPHA),
• Rapid plasma reading (RPR),

• Other
  tests
• Haematological and biochemical tests in
  leptospirosis,
• Antimicrobial sensitivity- high doses of
  penicillin will be effective against
• Leptospira interrogans.
• ELISA test,
• Polymerase chain reaction (PCR).

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Culture"

• Microaerophilic,
• Hardly to grow in routine culture,
• Able to survive in some fluid including citrate
  whole blood,
• Maintained by intratesticular inoculation in
  rabbit ??,

Transmission

• Direct or indirect contact with urine of infected
  animal,
• Enter damaged skin which has immersed for a long
  time in water or mud contaminated
• with infected urine,
• Microorganism penetrate the lining of mouth,
  nose, eyes.
• Person to Person transmission really occur.

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Economic Importance

• In ruminants spirochetes are beneficial their
  chemical activity help
• the cow and other ruminants to digest food.
• Spirochetes also live in harmony with mussels and
  oyster, where the bacteria help in feeding by
  acting as cilia to sweep food into mollusks
• Spirochetes known as aquaspirillium
  manetotacticum is of interest to microbiologist
  because it is one of a number of bacteria that
• possess magnetic particles. This particles allow
  a bacterium to orient
• itself in water in relation to earths magnetic
  field.

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Thank you