Chapter 21: Miscellaneous Bacteria

Spirochetes

Spirochetes

• Thin, regular, coiled cells

• Live in the oral cavity, intesitnal tract, and perigenital renions of humans and animals

• Pathogens are stict parasites

• Use endoflagella for movement

  • Move in a winding pattern

Treponema pallidum

• Thin, regular coiled cells

• Causes syphilis

• Extremely fastidious and sensitive

• Cannot live outside of the host

Syphilis

• Caused by treponema pallidum

• Sexual and transplacental transmission

• Primary, secondary, latent and tertiary

Primary syphilis

• Treponema pallidum spirochete binds to the epithelium, multiplies, and forms a chancre at the site of inoculation

  • Mouth or genitals

• Fluid from the chancre is highly contagious

• Chancre spontaneously heals as the spirochete moves into the blood

Secondary syphilis

• Treponema pallidum spirochete multiplies in the blood stream

• Rash forms on the skin, palms and soles, with fever, headache, and a sore throat

• Rash does not hurt but can persist for months

Latency and tertiary syphilis

• After secondary, ~30% enter a latent period that can last 20 years

• Tertiary syphilis forms if left untreated

• Damages multiple tissues and organs

• Gummas develop (painful swollen tumors)

Congenital syphilis

• Treponema pallidum can pass through a placenta to a fetus

• Fetal symptoms include nasal discharge, skin eruptions, bone deformation, and nervous system abnormalities

• Late form causes stigmata in the bones, eyes, inner ear, and joints

• Hutchinson’s teeth form = notched, barrel-shaped teeth

Leptospira interrogans

• Species of leptopira (tight, irregular coils with hooks at one or both ends)

• Causes leptospirosis

• Usually in tropical or warm climates

Leptospirosis

• Caused by leptospira interrogans (zoonosis)

• Bacteria shed in the urine

• Infection caused by contact with contaminated urine

• Causes sudden high fever, chills, headache, muscle aches, conjunctivitis, and vomiting

Borrelia

• Large spurochetes with 3-10 coils irregularly spaced and loose

• Transmitted via arthropod vector

• Borrelia hermsii

• Borrelia burgdorferi

Borrelia hermsii

• Transmitted by ticks; mammalian reservoirs = squirrels and chipmunks

• Causes relapsing fever

• After 2-15 days of incubation, patients have high fever, shaking, chills, headache, and fatigue

  • Nausea, vomiting, musche aches, abdominal pain

  • Damage to the liver, spleen, heart, kidneys, and cranial nerves

• Parasite changes, immune system responds and causes recurrent relapses

Borrelia burgdorferi

• Aquired by ticks

• Nonfatal, slowly progressive syndrome that mimics neuromuscular and rheumatoid conditions

• 50-70% of patients get bull’s eye rash

• Fever, headache, stiff neck, and dizziness

Vibrio

• Gram negative

• Comma shaped rods

• Singal polar flagellum

• Survive in the intestines

Vibrio cholerae

• Comma shaped bacteria

• Fermentative and grow on ordinary or selective media

• Causes cholera

• Possess unique O (somatic), H (flagella), and membrane receptor antigens

Cholera

• Caused by vibrio cholerae

• Usually in warm climates

• Spreads by ingestion of contaminated food or water

• Infects the mucous barrier of the small intestine

• Cholera toxin causes electrolyte and water loss

• “Rice water stool”; dehydration

Vibrio parahaemolyticus

• Causes gastroenteritis

• From raw seafood

• Symptoms similar to cholera

Vibrio vulnificus

• Causes gastroenteritis

• From raw oysters

• Serious complications in persons with DM or liver disease

Campylobacter jejuni

• Slender, curved, or spiral bacilli (s-shaped or gullwinged pairs)

• Polar flagella

• Important cause of bacterial gastroenteritis

• Transmitted via food and beverages

• Adheres and burrows through the mucus in the last segment of the small intestine and multiplies

• Heat labile enterotoxin CJT

Helicobacter pylori

• Gastric pathogen

• Curved cells

• Causes 90% of stomach and duodenal ulcers

• cofacto r in stomach cancer

• Produces urease = converts urea into ammonium and bicarbonate

Rickettsias

Intracellular pathogens that rely on an arethropod vector

Typhus group

• Epidemic typhus

• Endemic typhus

Spotted fever group

Rocky mountain spotted fever

Richettsii prowazekii

• Causes epidemic typhus

• Carried by lice

• Starts with a high fever, chills, headache, rash

• Brill-zinsser = chronic recurrent form

Rickettsii typhi

• Causes endemic typhus

  • Harbored by mice and rats

  • Occurs sporadically in areas of high flea infestation

  • Milder symptoms

Rickettsii rickettsia

• Causes rocky mountain spotted fever

• Zoonosis carried by dog and wood ticks

• Most cases in the south east and easter seaboard

• Fever, chills, headache, followed by a distinct spotted rash

• Can damage the heart and CNS

Coxiella burnetti

• Intracellular parasite related to rickettsiaceae

• Harbored by vertabrates and arthropods

Q fever

• Caused by coxiella burnetti

• Infectious material inclused urine, feces, milk, and droplets

• Usually inhaled , causing pneumonitis, fever, and hepatitis

Chlamydiaceae

• Small gram negative, obligate intracellular parasites

• Alternate between two stages in its life cycle

  • Elementary body

  • Reticulate body

Elementary body

• Small, metabolically inactive extracellular infectious form released by the infected host

• Cannot replicate on its own

Reticulate body

• Noninfectious, actively dividing form

• Grows within host cell vacuoles

Ocular trachoma

• Chlamydial disease of the eye

• Severe infection

• Deforms eyelid and cornea

• May cause blindness

Inclusion conjunctivitis

• Chlamydial diseas of the eye

• Occurs as a baby passess through the birth canal

• Prevented by prophylaxis

Chlamydiosis

• Sexually transmitted chlamydial disease

• Most prevalent STD

• Long term reproductive damage

• Asymptomatic in 70% of women and 10% of men

Nongonococcal urethritis (NGU)

• Sexually transmitted chlamydial disease

• Affects males

• Inflammation of the urethra

• Mimics gonhorrea

• Do not involve gonococci

Pelvic inflammatory disease (PID)

• Sexually transmitted chlamydial disease

• Affects women

• Cervivitis with a white drainage, endometritis, and salpingitis

Lymphogranuloma vereneum

• Sexually transmitted chlamydial disease

• Disfiguring disease of the external genitalia and pelvic lymphatics

Mycolasma pneumoniae

• Natually lacks a cell wall

• Pleomorphic

• Causes primary atypical pneumonia; “walking pneumonia”

• Pathogen slowly spreads over interior respiratory surfaces

• Causes fever, chest pain, and sore throat