Ch. 11 - Food and Waterborne Bacterial Diseases Flashcards Preview

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Flashcards in Ch. 11 - Food and Waterborne Bacterial Diseases Deck (25):
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Dental carries

Tooth decay

Causative agents: streptococcus mutans, streptococcus sobrinus

Results from:

Plaque building, Dietary carbohydrates (into acid by bacteria), Acidogenic bacteria (acid-producing)

Bacterial cells on pellicle will start metabolizing carbohydrates into acids

Symptoms: toothache, sensitivity

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Plaque

Biofilm

Contain salivary proteins, food debris, and bacterial cells and their products

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Gingivitis

Inflammation of gums around the teeth

Bacterial cells in plaque multiply and build up between teeth and gums

Subgingival plaque - between teeth and gums

Symptoms: swollen, soft gums; bleeding gums

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Periodontal disease (periodontitis)

Disease of soft tissue and bone supporting teeth

Bacteria in dental plaque - subgingival plaque

Symptoms: Ulcers and bleeding along gingival margin; Degradation of periodontal ligaments and bone - bond resorption; Loosened or lost teeth

Etiological agents: mixed infections by anaerobic gram negative bacteria -- secrete toxins (hyaluronic acid) that directly injure the periodontal tissues

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Streptococcus mutans

Gram pos

Major cause of dental caries (with streptococcus sobrinus)

Ferment dietary carbs (sucrose) into lactic acid

Acids in plaque cause demineralization of enamel -- lead to cavity (tiny hole or lesion in enamel)

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Intoxication

bacterial toxins ingested

(botulism, staph and clostridial food poisoning)

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Infection

live bacteria ingested

(salmonellosis, cholera)

longer incubation period than intoxication --> bacterial cells must establish themselves in body after ingestion

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Gastroenteritis

inflammation of the stomach and intestines

nausea, vomiting, stomach cramps, diarrhea

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Staphylococcal food poisoning

causative agent: staphylococcus aureas (anaerobic, Gram Pos)

intoxication - enterotoxin ingested-- consumed in protein-rich foods (dairy, meat, fish)

enterotoxin heat resistant (100C will not kill)

incubation period: 3-5hrs

Symptoms: cramps, pain, vomiting, nausea -- gastroenteritis for several hours rapid, complete recovery

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Botulism

causative agent: Clostridium botulinum (anaerobic, Gram Pos)

intoxication - exotoxin ingested

neurotoxin - inhibits release of neurotransmitter AcCH; prevents muscle contraction

Causes: flaccid paralysis - limbs lose tone, become flabby respiratory distress - failure of diaphragm and rib muscles

Treatment: antitoxin, breathing assistance (ventilators)

Prevention: heating foods before eating for at least 10 min (toxin destroyed on exposure to temp of 90C for 10 min)

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Floppy Baby Syndrome

infant botulism

infants 3-24 mo. - not established normal microbiome

produce low muscle tone

no honey

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Botox

Botulism toxin type A

Relieve movement disorders by involuntary sustained muscle contractions (stuttering, crossed eyes)

temporary relive of facial wrinkles and frown lines

relief of excessive sweating and migraines

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Inflammatory Gastroenteritis

bacterial gastroenteritis

diarrhea, vomiting, fever, no bloody stools

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Invasive Gastroenteritis

bacterial gastroenteritis

bacterial invasion beyond intestinal lumen

fever, diarrhea, vomiting, dysentery (blood and mucus in stool)

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Cholera

Inflammatory gastroenteritis

causative agent: Vibrio cholerae (aerobic, Gram Neg)

V. cholerae: -often cosumed with raw oysters and water -fecal contamination of water

cells susceptible to stomach acid -- need large infectious dose to colonize intestines

cells secrete exotoxin; exotoxin = choleragaen

loss of fluid and electrolytes = rice water stools (up to 1 L/hr)

untreated: fluid loss thickens blood -- slow blood flow to brain -- shock and coma

Treatment: oral rehydration therapy

Prevention: clean water and food

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Clostridium difficile infection

Inflammatory gastroenteritis

causative agent: clostridium difficile (anaerobic, Gram Pos, spore-forming rod)

transmission: fecal-oral route toxins

enterotoxin - fluid loss and diarrhea

cytotoxin - further mucosal injury (pseudomembranous colitis)

pseudomembranous colitis - inflammation of colon; colon can rupture

drug resistance and virulence (potent toxins)

Factors: antibiotics; exposure in hospital setting (endospores transferred via healthcare workers' hands)

Treatment: start/stop antibiotics; vancomycin, fluid replacement; fecal transplants

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Listeriosis

Inflammatory Gastroenteritis

causative agent: Listeria monocytogenes

transmission: oral-fecal route, water, milk - contaminated food

psychrophilic - thrive in cold environment (4C); fridge temps do not supress

immunocompromised - form of meningitis: infected macrophages cross blood-brain barrier - inflammation of CNS

pregnant - perinatal infection - miscarriage or stillbirth

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 E. coli

anaerobic, Gram Neg

human colon contains (indigenous) -- other E. coli serotypes can be pathogenic

transmission: fecal-oral route

E. coli diarrheas cause various forms of gastroenteritis

1. Enterogenci E. coli (ETEC) 

2. Enteropathic E. coli (EPEC) 

3. Enterohemorrhagic E. coli (EHEC) 

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Enterogenic E. coli (ETEC)

inflammatory gastroenteritis

produce 2 toxins: heat labile - similar to cholera; heat stable - traveler's diarrhea

low fluid loss, vomiting, cramps, nausea, diarrhea 3-7 days

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Enteropathic E. coli (EPEC)

inflammatory gastroenteritis

fecal-oral transmission

watery diarrhea

diarrhea in infants (esp. when sanitation lacking)

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Enterohemorrhagic E. Coli (EHEC)

Invasive Gastroenteritis

produce Shiga toxin = Shiga toxin producing E. coli (STEC)

Shiga toxin: acid tolerant; block protein synthesis

most dangerous of E. coli serotypes: E. coli 0157:H7

Hemorrhagic colitis - bloody diarrhea

Hemolytic Uremic Syndrome (HUS) - kidney failure; damaged RBC clog glomerulus

Reservoir - cattle -- exists in intestine of healthy cattle -cattle feces -undercooked hamburger

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Salmonellosis

Invasive Gastroenteritis

causative agent: salmonella enteritidis - found in unpasteurized milk or poultry products

transmission: fecal-oral route; live animlas; foodborne and waterborne -salmonella species infect chickens and turkeys when normal bacterial species of gut are absent

large infectious dose required to initiate illness

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Campylobacteriosis

Invasive Gastroenteritis

causative agent: camplylobacter jejuni

transmission: oral-fecal route - contaminated food/water; consumption of contaminated poultry or dairy products

most common cause of bacterial gastroenteritis in the US

Recent outbreaks due to drinking raw milk

Treatment: fluid replacement; erythromycin

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Gastric Ulcer Disease

Invasive Gastroenteritis

causative agent: Helicobacter pylori

Transmission: person-to-person; likely involved contaminated food/water

gastric ulcer - penetrate stomach mucasa layer; attached to stomach wall

secretes enzyme urease - digests urea, produce ammonia

ammonia neutralize acid in area of stomach (allow bacteria to survive)

urea->ammonia + CO2

ammonia + H. pylori cytotoxin---cause destruction of mucus-secreting cells -- expose underlying tissue to stomach acid

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