Lecture Notes Flashcards

Flashcards of lecture notes on Enterobacteriaceae, Escherichia, Shigella, Salmonella, Yersinia, Citrobacter, Klebsiella, Enterobacter, Serratia, Proteus, Edwardsiella, Providencia, Vibrio cholerae, Campylobacter jejuni, Helicobacter pylori, and Virus Structure

Enterobacteriaceae

Family of bacteria found in the intestinal tract, including normal flora, opportunistic pathogens, and frank pathogens; Gram (-) non spore forming rods

O antigen

Somatic antigen of Enterobacteriaceae; Heat stable, located in the cell wall and initiates symptoms in the host.

H antigen

Flagellar antigen of Enterobacteriaceae; Heat-labile, found in the flagellum (only in motile organisms).

K antigen

Capsular antigen of Enterobacteriaceae; Heat labile, polysaccharide found in some species (named after Klebsiella).

Enteritis

Inflammation of the intestine.

Gastroenteritis

Inflammation of the digestive tract (stomach and everything below).

Enteric fever

Acute illness presenting as fever, headache, abdominal pain, and occasional skin rash.

Food poisoning

Ingestion of food containing a preformed toxin; No growth of bacteria in the host is required.

Emesis

Vomiting

Morbidity

Incidence of disease; Number of cases.

Mortality

Incidence of death.

Escherichia coli (E. coli)

Common inhabitant of the intestinal tract; Used as an indicator of water polluted by sewage; Involved in food digestion (source of vitamin K).

Enteroaggregative E. coli (EAggEC)

E. coli that causes watery diarrhea, vomiting, dehydration, and abdominal pain by adhering to the mucosal surface of the intestine.

Enteropathogenic E. coli (EPEC)

E. coli that is noninvasive; Adheres to the cells of the small intestine and destroys microvilli without actual invasion; causes low-grade fever, malaise, vomiting, and diarrhea.

Enterotoxigenic E. coli (ETEC)

E. coli that is associated with diarrhea of infants and adults in tropical and subtropical climates; Produces heat labile and heat stable toxins; causes nonbloody, watery diarrhea, nausea, and abdominal pain.

Enteroinvasive E. coli (EIEC)

E. coli that causes dysentery and symptoms similar to Shigella disease; Invasive and penetrates the host cells, causing damage and destruction to the large intestine mucosa; causes fever, severe abdominal cramping, malaise, watery diarrhea and toxemia.

Enterohemorragic E. coli (EHEC)

Frank pathogen E. coli

Shigellosis

Bacillary dysentery characterized by blood, pus, and mucus in stools, abdominal pain, and cramps; Caused by Shigella.

Verotoxin I and Verotoxin II

Cytotoxins specific for the colon produced by some strains of E. coli and Shigella; Can cause Hemolytic Uremic Syndrome.

Salmonellosis

Gastroenteritis caused by Salmonella; Characterized by low grade fever, abdominal pain, and diarrhea (non-bloody).

Typhoid fever

Caused by Salmonella typhi; Symptoms include high fever, headache, myalgia, and GI distress; May develop rose rash.

Yersinia enterocolitica

Produce an infection that mimics symptoms of appendicitis: fever, nausea, acute sharp pain in abdomen, and diarrhea. Responds to antibiotics pretty well. Can cause community outbreaks of diarrhea

Yersinia pestis

Causative agent of bubonic and pneumonic plague

Citrobacter

Normal intestinal flora; of small clinical interest

Klebsiella

Large non motile bacterium produces large mucoid colonies when plated on nutrient media and possess large capsules; cause wound infections, bacteremia, pneumonia (blood sputum), and UTI.

Enterobacter

Normal flora of human intestinal tract and domesticated livestock; cause opportunistic infections of the urinary tract.

Serratia

Opportunistic pathogens associated with nosocomial outbreaks; can resist ranges of antimicrobials

Proteus

Normal intestinal flora in half of the population; Cause urinary tract infections and hospital acquired infections; Highly motile and forms “swarming colonies”.

Edwardsiella

Rarely causes human infection; Found in aquatic animals and reptiles; Associated with gastroenteritis, wound infection, and bacteremia.

Providencia

Rarely causes human infection; Associated with nosocomial urinary tract infections; Infections are difficult to treat because of antimicrobial resistance.

Vibrio cholerae

Frank pathogen; Curved Gram (-) rods; requires water; Acute symptoms: nausea and vomiting early on, profuse watery diarrhea (nonbloody (noninvasive) rice water stool

Campylobacter jejuni

Cause acute diarrheal disease, can become bloody;Gram negative rods; Highly contagious by fecal to oral route; Found in public pools and this organism can survive chlorination.

Helicobacter pylori

Causative agent of stomach and intestinal infections; Gastric and Duodenal ulcers; Spiral shaped cell and has an H antigen (highly motile)

Icosahedral

Virus shape that looks like a hexagon; 17-23 triangular faces. Will always look symmetrical.

Helical

Virus shape; open ended tube

Capsid

a protein rigid outer coating that surrounds a virus’s nucleic acid and genetic information

Obligate intracellular parasites

Cannot reproduce independently, requires a host cell

Attachment fibers/spikes

Specific angled part that has to specifically attach and fit into receptor sites on the host cell. Stick off of the virus.

Naked virus

result of released viruses from lysis

Enveloped virus

virus that is result of budding (exocytosis)

Bacteriophage

Icosahedral that contains capsid, genetic information, sheath, base plate, and attachment fibers. Infects bacteria.

Lysis

Rupturing the host cell and the viruses leave the host cell at once.

Budding

Viruses leave the host cell by exocytosis, where the layer of the host cell membrane surrounds one virus at a time, and it is exported out.

Proteus Mirabilis

• : cause of wound an urinary tract infections

Proteus Vulgaris

isolated less often in the lab and usually targets immunosuppressed individuals.

Providencia alcalifaciens

has been associated with diarrheal disease in children Infection is so rare, enterobacteriaceae should be considered before providencia as being causative agent