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spiral bacteria, axial filament.
Most are free-living
- Spirochetes
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syphilis. Sexually transmitted. No growth on any laboratory media.
- Treponema pallidum
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Relapsing fever. Tick borne.
Borrelia recurrentis
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Lyme disease. Tick borne. Headache, stiff neck, arthritis.
Borrelia burgdorferi
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Flagellated, no axial filaments. Most are harmless.
Aerobic/microaerophilic, motile, helical/vibrioid
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among most common causes of diarrheal illness in the US and other developed countries. May lead to septicemia. Acquired orally. Invades intestinal epithelia
Campylobacter spp
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responsible for >85% of gastric and duodenal ulcers.
Helicobacter pylori
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Inhabit soil, water, plants and animals (moist areas). Motile, many pigments,metabolically active (many enzymes) but may use few of the common nutrients and grow on anything. Extremely invasive and toxigenic in compromised patients (weakened ability to resist infectious agents)
- Aerobic rods and cocci
- Pseudomonas aeruginosa
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Urinary tract infections (UTI), septicemia, abscesses, burns, wounds.
Nosocomial infections
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Ubiquitous in warm, moist environments.
Legionella spp.
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Legionellosis, Legionnaires disease (pneumonia-like). Many toxins. Spread by aerosols. Asymptomatic infections common in all age groups.
Legionella pneumophila
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diplococci. Pathogenic species usually associated with leukocytes (neutrophils in particular).
Neisseria spp.
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gonorrhea. No capsule. Pili on virulent forms. Highly toxic LPS
Neisseria gonorrhoea
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found only in humans. Inhalation, pili attach, invasion to blood, fulminant infection,circulatory collapse, meningitis
Neisseria meningitidis
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Obligate parasites of animals (incl. humans). Often found intracellularly (survives phagocytosis). Transmitted by ingestion or passage through skin or mucous membranes.
Brucella spp.
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chronic, and involves many tissues. Endotoxin mediated.
Undulant fever (Brucellosis)
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Whooping cough, infant immunizations have been very effective. Respiratory transmission. Pertussis toxin and other toxins. Relatively non-invasive.
Bordetella pertussis
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Tularemia (ulcers, necrotic lesions, fever, malaise). Entry through abrasions following animal contact, insect bite, ingestion or inhalation. Highly infectious and toxic. Rabbits.
Francisella tularensis
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natural habitat for most is intestinal tract.Some are normal flora and cause incidental disease; some are regularly pathogenic
Enteric bacteria
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Common intestinal inhabitant. UTI's and food poisoning (traveler's diarrhea); spread by fecal contamination. LPS and many other toxins (heat stable and labile toxins). Most common normal flora, u get from humans.
Escherichia coli
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Common in many animals. Transmitted to humans by oral route. Enteric (typhoid) fever, bacteremias, and enterocolitis. Invasive (gut to blood) and toxigenic. Poop on hand -> ingestion. Typhoid mary.
Salmonella. Salmonellosis not as deadly as salmonella.
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Humans only. Shigellosis (dysentery) and traveler's diarrhea. LPS, exotoxins, and enterotoxins (interfere with nutrient uptake). Appearance in blood is rare.
Shigella
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Normal flora of gut flora. Diseases similar to E. coli, and pediatric septicemia, pneumonias in the immunocompromised, esp. chronic alcoholism
Klebsiella pneumoniae
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Normally free-living. Very opportunistic. Nosocomial infections- UTI's and respiratory tract infections (RTI)
Serratia marcescens
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UTI's, wound infections, and infant diarrhea. Highly motile.
Proteus spp.
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Many toxins. Multiply rapidly in blood and other tissues. Bubonic plague: Rats to Fleas to Humans. Pneumonic plague: Respiratory aerosols.
Yersinia pestis
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common inhabitants of soil, water, & animals.
Enterobacter cloacae and E. aerogenes
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UTI and sepsis.
Nosocomial infections
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curved rods (comma shapes). Among most common inhabitants of surface waters.
Vibrio
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cholera. Contaminated water, poor sanitation. Potent enterotoxin.
Vibrio cholerae
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A halophile. Gastroenteritis from raw or poorly cooked fish and shellfish
Vibrio parahaemolyticus
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primarily animal pathogens. Transmitted to humans by dog or cat bite.
Pasteurella
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in humans, local lymphadenopathy, followed by widespread infection, septicemia and chronic respiratory infection. Toxigenic.
Pasteurella multocida
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Non-encapsulated may be normal flora. Encapsulated is pathogenic. Spread by inhalation. Meningitis and earache in infants and children; laryngotracheitis. RTI in children and adults.
Haemophilus influenza
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Normal intestinal flora. Peritonitis, following puncture wounds
Bacteroides
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Normal oral flora. Dental abscesses
Fusobacteria
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reproduce only in host cells
Obligate intracellular parasites
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Most are arthropod borne. Multiply in endothelial cells of many organs & cause necrosis
Rickettsia
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epidemic typhus. Grows in cytoplasm
Rickettsia prowazeckii
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Rocky Mountain Spotted Fever. Grows in nucleus
Rickettsia rickettsia
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Q fever. Inhalation. Influenza, pneumonia, hepatitis, encephalopathy.
Coxiella burnetti
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Cannot synthesize ATP. Persistent parasites. Blindness, respiratory disease, venereal disease.
Chlamydia spp.
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No cell wall. Very small. Often normal flora of mouth, gut and urogenital tract. Can be intracellular parasites. Atypical pneumonia and urethritis, esp. in compromised host, post-partum disease. Toxigenic.
Mycoplasma and Ureaplasma spp.
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