Curviform G- Bacteria

Vibrio cholera

Properties

  • Comma-shaped bacteria

  • Strictly attacks humans

  • Related metabolically to Enterobacteriaceae

  • Fermentative

  • Selective media with bile at 37°C

  • Oxidase positive

  • Unique O and H antigens

Vibrio cholera

Cholera

  • A devastating disease (El Tor biotype)

  • Transmitted by food and water

  • Uncommon in USA, except in Gulf of Mexico area (shellfish)

  • Infectious dose:108 cells

  • Pass stomach thru food into the duodenum and jejenum

  • Penetrate mucous barrier by flagella

  • Never enter cells (epipathogens)

  • Only multiplies outside epithelium

  • Virulence due to enterotoxin (cholera toxin)

  • Toxin make cells lose water rapidly

  • Disease spreads with force

  • Patients loses 1 liter water per hour!!

  • Untreated patient may lose 50% of body weight and death may occur within 48 hrs

Therapy

Tetracycline, trimethoprim-sulfa

Replacement of water and electrolytes

Prevention

Proper sewage disposal Water purification

Vaccines are not effective

Watch seafood

History to Read

  • Cholera in London
  • Indian Rivers (Ganges and Brahmaputra)
  • Peru (1991)

Vibrio parahaemolyticus

  • Occurs in warm climate

  • Alkaline conditions

  • Causes seafood gastroenteritis by eating raw shellfish contaminated with wastewater

  • Bacteria colonize chitin exoeskeleton of shrimps and crabs

  • Keep food refrigerated to keep infectious dose low

  • Occasionally infects wounds of swimmers, dock workers, seafood cooks, etc.

Campylobacter jejuni

  • Slender, curved or spiral bacilli, propelled by polar flagella

  • Inhabits IT, UT and oral cavity of humans and animals

  • Now considered one of the most important causes of bacterial gastroenteritis worldwide

  • Thru contaminated milk, meat, chicken, drinks

  • Incubation period: 1-7 days

  • Bacteria reach the mucosa at the last segment of the small intestine (ileum) near its junction with colon where they multiply

Symptoms

  • Headache
  • Fever
  • Abdominal pain
  • Diarrhea (bloody and watery)

Cause

Enterotoxin (CJT) stimulates secretory diarrhea (like cholera does)

Therapy

  • Rehydration
  • Electrolytes
  • Antibiotics

Campylobacter fetus subsp. venerealis

  • Causes a STD in sheep, cattle, goats

  • Agent of abortion in these animals

  • Also in humans though mode of infection is still not clear

  • Opportunistic pathogen on debilitated persons or women late in pregnancy

  • Linked to meningitis, pneumonia, arthritis, fatal septicemic infections in newborn, STD (proctitis in adults)

Spirillum minus

Rat Bite Fever

 

  • Also called "sodoku" (japanese word for poison)

  • A rare zoonosis mostly in Far East (Japan)

  • Urban areas with poor sanitation and high rat populations

  • Septicemia, eye and lung infections

  • Fleas and others arthropods do not serve as vectors

  • Can not be cultivated on artificial media

  • Control with antibiotics

Streptobacillus moniliformis

  • Equivalent of previous disease but most common in USA

  • Affects biomedical personnel who handle laboratory rats

The Rickettsias


Genera

Rickettsia

Coxiella

Bartonella

Bacteria Transmitted by

  • Lice
  • Fleas
  • Ticks
  • Mites
  • Chiggers
  • Cats

Diseases

  • Typhus

  • Spotted fever scrub typhus

  • Q-fever trench fever

  • Cat-scratch fever

Size

  • 0.3 to 0.6 µm wide
  • 0.8 to 2.0 µm long

Rickettsia prowazekii

Epidemic typhus

  • Worldwide distribution

  • Systemic infection transmitted by rubbing the feces of body lice into bite

  • Inhalation

  • Humans is the primary reservoir

  • Overcrowded conditions

  • Invasion of the vascular endothelium causing necrosis and hypotension

  • Disease is controlled with antibiotics and recovery provides immunity


Rickettsia typhi

Murine typhus

  • Less virulent than louse-born typhus

  • Transmitted by the feces of rat fleas and enters the host when bites are scratched

  • Inhalation

  • Primary reservoir

  • Rodents (rats)

  • Worldwide distribution

Rickettsia tsutsugamushi

Scrub Typhus

  • Endemic disease in Asia

  • Transmitted by chigger bites

  • Reservoir: rodents

  • Fatal if untreated

  • Respond well to antibiotics

Rickettsia rickettsii

Rocky Mountain Spotted Fever

  • North America (Montana, Idaho)

  • Reservoirs are small mammals (dogs)

  • Vectors: wood tick, American dog tick, and Lone Star tick

  • Transmits to humans by tick bites and aerosols
    (See transmission cycle in textbook)

Symptoms

  • Fever
  • Chills
  • Headache
  • Muscular pain
  • Spotted rash on all body

Epidemiology

  • Most cases are reported in eastern seaboard
    and SE states (not in Idaho and Montana)

  • Does not occur in Southern Texas

If Untreated

  • Restlessness
  • Hypotension
  • Coma
  • ThrombosisH
  • Hemorrhage
  • Convulsions
  • Tremor

Isolation

  • Expensive

  • Requires specially-qualified personnel and special laboratory facilities

Detection

  • ELISA

Therapy

Tetracycline and chloramphenicol

Prevention

Remove ticks from dogs without crushing them ==> use gloves

New Vaccine

Rickettsia grown in chicken embryonic and tissue cultures

Other Rickettisioses

Coxiella burnetii

Q-Fever

  • Q for Queensland (Australia)

  • Highly resistant because of an usual type of spores that are release when cell disintegrates

  • Transmitted by ticks, some wild & domestic vertebrates, and aerosols

  • Sources of infections: urine, feces, milk; and, aerosols from infected animals

  • Portals of entry: lungs, skin, conjunctiva, gastro-intestinal tract

  • CA and TX highest case rates in USA

  • Avoid drinking raw milk

  • Fever, chills, head and muscle aches

Bartonella quintana

Trench Fever

  • In 1st WWW afflicted about 1 million people

  • Unlike typhus rickettsia, does not multiply intra-cellularly and does not kill the louse vector

  • 5-6 day of fever (5 day = quintana), leg and tibia (shinbone fever); head, and muscle pains

  • Persist in blood and can be recurrent


Bartonella henselae

Cat-Scratch Fever

  • Caused by by cat scratch or cat bites

  • Systemic infection that travels from the initial site along the lymph vessels

  • Responds to antibiotics