Spiral-Shaped (Spirochetes) Bacteria (Lecture 17)

Lecture 17

What are the structural features of Spiral-Shaped (Spirochetes) bacteria?

Gram NEGATIVE

Flagella

Most spirochetes are non-pathogenic

What are the structural features of Campylobacter?

Tiny

Gram NEGATIVE

Flagellated

Comma, spiral, or s-shaped

50+ species but only 4 are common human pathogens

Virulence Factors:

• Antiphagocytic polysaccharide capsule and adhesins

• Cytotoxic enzymes

• Enterotoxins

• Zoonotic from ill-prepared poultry.

  • Requires high dose of bacteria

What are the clinical manifestations of Compylobacter?

C. jejuni— MOST common cause of bacterial gastroenteritis in the US

• Damages mucosal surfaces of jejunum, ileum, and colon

• Hyperactivation of immune cells and CYTOKINE STORM

Pathogenesis is related to antigenic cross-reactivity.

Guillain-Barre Syndrome and reactive arthritis.

What is the treatment for Campylobacter?

Sever cases treated with Erythromycin and Azithromycin

What are the structural features of Helicobacter?

Tiny

Gram NEGATIVE

Flagellated

Slightly helical

Gastric helicobacter/Enterohepatic Helicobacter

Virulence:

• Urease and Mucinase

• Phospholipase

  • Vacuolating cytotoxin A

What are the clinical manifestations of Helicobacter?

H. Pylori is caused by blockage of acid production and neutralization of gastric acids. Localized tissue damage caused by virulence factors.

Gastritis

Peptic ulcers

Gastric adenocarcinoma

MALT B-cell lymphoma

What is the treatment for Helicobacter?

PROTON PUMP INHIBITOR (omeprazole)

Tetracycline, metronidazole, clarithromycin

What are the structural features of Treponema pallidum?

Small

Thin

Tightly coiled spirochetes, pointy straight ends

Serology is primary diagnostic test for SYPHILIS

Virulence: Hyaluronidase: Facilitates perivascular infiltration

Fibronectin: protects against phagocytosis

What are the clinical manifestations of Treponema pallidum?

Pallidum: SYPILIS

Endemism: Bejel

Pertenue= Yaws

Tissue destruction is primarily results from host IMMUNE RESPONSE.

Syphilis is not highly contagious. 30%

Congenital syphilis: leads to BLINDNESS, deafness, and cardiovascular syphilis in untreated infants

What is the treatment for Treponema pallidum?

PENICILLIN for ALL stages of syphilis

Doxycycline or tetracycline if patient is ALLERGIC to penicillin

How do you test for Treponema pallidum?

Nontreponemal Tests: RPR and VDRL

Treponemal tests: FTA-ABS and MHA-TP

What is Syphilis caused by?

Treponema pallidum

What is the clinical manifestations of OCULAR SYPHILIS?

Uveitis is one of the more frequent ocular manifestations of syphilis.

Can involve all ocular structures.

What is the treatment of OCULAR syphilis?

IV Penicillin G for 10-14 days

Followed by IM Penicillin weekly for 3 weeks

What are the structural features of Borrelia?

Large Spirochetes

LYME DISEASE— B. burgdorferi

Virulence: Outer surface antigens help bacteria evade the host’s immune response

What are the clinical manifestations of Borrelia?

B. burgdorferi: ticks causing LYME DISEASE

Bull’s eye rash call erythema

What is the treatment for Borrelia?

ANTIBIOTICS can cure if within a month of exposure.

Penicillin or tetracycline

What are the structural features of Leptospira?

Thin

Motile

Coiled Spirochetes with a HOOK

Obligate aerobes.

Can penetrate the skin through minor breaks in the epidermis or mucous membranes

What are the clinical manifestations of Leptospira?

Leptospirosis: 1st phase: Flu-like symptoms

2nd phase: Sudden onset of stuff and CONJUNCITVAL erythema

Weil’s Disease: Jaundice, vascular collapse, thrombocytopenia, conjunctival erythema, etc

What is the treatment for Leptospira?

IV Penicillin OR Doxycycline