Chapter 1.9 Enterics Flashcards
What is the shape of enterics?
Gram-negative
Where are the enterics normally located?
In the normal intestinal flora
What are the main groups of enterics?
Enterobacteriaceae, vibrionaceae, pseudomonadaceae, and bacteroidaceae
What can contaminate water to cause disease from enterics?
Feces
What bacteria is found in contaminated fecal water?
E. Coli which is normally only found in the intestine and not outside of the body
How can lactose help with E.coli findings?
If lactose if fermented, gas is produces and the dye is visualized– then E. Coli is in the water
What color is E.coli on a streak EMB agar plate?
Metallic green sheen
What are the 3 major surface antigens of the enterics?
O antigen, K antigen, H antigen
What are the main 2 types of diseases caused by the enterics?
Diarrhea with or without systemic invasion
Infections of urinary tract, pneumonia, bacteremia, and sepsis
Who is most likely at risk for an infection from the enterics?
Hospitalized patients
What is the appearance of diarrhea when there is on cell invasion from the enterics?
Watery diarrhea without systemic symptoms- caused by enterotoxin that causes fluid and electrolyte loss from intestinal cells
What is the appearance of diarrhea that invades the intestinal epithelial cells from the enterics?
Red blood cell leakage into the stool from systemic immune response and local WBC infiltration
What enterics are associated with red blood cell leakage into the stool?
E. Coli, Shigella, and Salmonella enteritidis
What clinical manifestations are present when the enterics invade the lymph nodes and bloodstream?
Abdominal pain, diarrhea with red and white cells, systemic symptoms, lymph node enlargement, bacteremia, and sepsis
What are the systemic symptoms associated with invasion of the lymph nodes and bloodstream from the enterics?
Fever, headache, white blood cell count elevation
What are examples of the enterics that invade the lymph nodes and bloodstream?
Salmonella typhi, Yersinia enterocolitica, Campylobacter jejuni
How can the enterics invade debilitating patients in hospitals nursing homes?
Through Foley catheters in the urethra
What are examples of hospital-acquired gram-negative?
E.coli, Klebsiella pneumoniae, proteus mirabilis, enterobacter, serratia, and pseudomonas aeruginosa
*also called nosocomial gram-negatives
Where is E.coli normally present without causing disease?
Colon
What causes E.coli to become pathogenic and cause disease?
When it combines with virulence factors
What are the virulence factors associated with E.coli?
Mucosal interaction
Exotoxin production- shiga-like toxin, heat-labile and stable toxin
Endotoxin- lipid A of LPS
Iron binding siderophore
What diseases can be caused by E.coli?
Diarrhea, Urinary tract infection, Neonatal meningitis, Gram-negative sepsis
Who can E.coli diarrhea affect?
Infants or adults
What is the usually cause of death from E.coli diarrhea?
Dehydration from water lost in stool
What is another name for E.coli diarrhea?
Travelers’ diarrhea
What are the 3 groups of diarrhea-producing E.coli?
EnteroToxigenic E. Coli (ETEC)
EnteroHemorrhagic E.Coli (EHE)
EnteroInvasive E.Coli (EIEC)
What toxins are associated with enterotoxigenic e.coli?
heat Labile Toxin (LT) and heat Stable Toxins (ST)
What is the clinical presentation of ETEC?
Severely watery diarrhea that looks like rise water
What toxin is secreted in enterohemorrhagic e.coli?
Shiga-like toxin (verotoxin)
What is the clinical presentation of someone with enterohemorrhagic e.coli?
Bloody (hemorrhagic) diarrhea and severe abdominal cramps
*called hemorrhagic colitis
How does hemolytic uremic syndrome relate to EHEC?
Associated with stain E.coli 0157:H7
Occurs secondary to infected hamburger meat at fast food chains
What are the characteristics of enteroinvasive e.coli?
Same as disease caused by shigella
EIEC can invade epithelial cells and produce Shiga-like toxin
What is the clinical manifestation of a person with EIEC?
Immune-mediated inflammatory reaction with fever
WBCs invade intestinal wall
Diarrhea is bloody with WBCs
What do different types of diarrhea from E.oli depend on?
Virulence acquisition from plasmids
How can E.coli for Urinary Tract Infections (UTI)?
Pili from E.coli allow travel through the urethra and infect the bladder (cystitis) and potentially the kidney (pyelonephritis)
What bacteria is the most common cause of UTIs?
E.coli usually in women and hospitalized patients with catheters
What are the patient symptoms of a UTI from E.coli?
Burning on urination (dysuria)
Having to pee frequently
Feeling of fullness in the bladder
What can E.coli cause in neonates in the first month of life?
Neonatal meningitis
How does E.coli sepsis occur?
Lipid A of LPS causes gram-negative sepsis in debilitated hospitalized patients
What type of pneumonia is caused by E.coli?
Hospital-acquired pneumonia
What diseases are caused by Klebsiella pneumoniae?
Sepsis, urinary tract infections
Who is most prone to Klebsiella pneumoniae?
Hospitalized patients and alcoholics
What is the clinical presentation of a person with Klebsiella pneumoniae?
Bloody sputum *looks like red jelly
Lung tissue destruction producing cavities
What is the function of Proteus mirabilis?
Breakdown urea
*often called urea-splitting Proteus
What diseases can be caused by Klebsiella pneumoniae?
Urinary tract infections and hospital-acquired infections
What would a urine sample from a patient with Proteus mirabilis show?
Alkaline pH
Where is enterobacter normally present?
Normal flora of intestinal tract
What infection is associated with Enterobacter?
Hospital-acquired infections
What infections are associated with Serratia?
Urinary tract infections, wound infections, and pneumoniaW
What is the main notable characteristic of Serratia?
Bright red pigment
What are the 4 types of Shigella?
Dysenteriae, flexneri, boydii, sonnei
What are the main characteristics of Shigella?
Non-motile, no flagella, does not ferment lactose, does not produce H2S
*used to distinguish from e.coli (lactose fermenter) and salmonella (produces H2S)
Where is Shigella found?
In preschool age children and nursing home populations
**Shigella is NEVER considered part of the normal intestinal flora– it is always a pathogen
What exotoxin is released by Shigella?
Shiga toxin- causing cell destruction
What is the clinical presentation of a person with Shigella?
Fever, abdominal pain, diarrhea that contains bright red blood and pus
What organisms are associated with the release of Shiga toxin?
Shigella, EHEC, and EIEC
What are the characteristics of Salmonella?
Non-lactose fermenter, motile, and produces H2S
What are the 3 groups of Salmonella?
Salmonella typhi, Salmonella cholerae-suits, and Salmonella enteritidis
*named according to the disease they cause
How is Salmonella different from other enterics?
Lives in the GI tracts of animals and infects humans when there is contamination of food or water with animal feces
*except Salmonella typhi is NOT transmitted from animal to man
What are the most common ways of getting Salmonella in the US?
Eating chickens and uncooked eggs
What is zoonotic?
An infectious diseases of animals that can be transmitted to man
What is unique about Salmonella typhi?
Not zoonotic and is carried only by humans
What is the illness caused by Salmonella typhi?
Typhoid fever (enteric fever)
What makes Salmonella a facultative intracellular parasite?
It invades the intestinal epithelial cells, lymph nodes and seeds multiple organ systems
What is the clinical presentation of a patient with Salmonella typhi?
Fever, headache, abdominal pain in lower right quadrant, diarrhea, rose spots on abdomen
What are rose spots?
Transient rash of small pink marks seen on light-skinned people with typhoid fever
Why is the story of Typhoid Mary important?
She was a carrier of typhoid fever and infected dozens of people that she cooked for
What does the systemic effect of Salmonella choleraesuis occur?
Travels through bloodstream to infect the lungs, brain or bone
Does not involve the GI tract
Who is particularly susceptible to Salmonella osteomyelitis?
Patients with sickle-cell anemia
What is the most common type of Salmonella infection?
Salmonella diarrhea (gastroenteritis)
What is the clinical presentation of a patient with Salmonella diarrhea?
Nausea, abdominal pain, and diarrhea that is water or contains mucous and trace blood
What is the shape of Yeresinia enterocolitica?
Motile gram-negative rod
What disease is associated with Yersinia enterocolitica?
Acute gastroenteritis (diarrhea)
What is the major source of Yersinia enterocolitica?
Animals from the transfer of fecal-oral route
What is the clinical presentation of a patient with Yersinia Enterocolitica?
Fever, diarrhea, and abdominal pain in right lower quadrant after ingestion of contaminated food
What is the pathogenesis of Yersinia enterocolitica?
Invasion and enterotoxin
What is the shape of vibrio cholera?
Curved gram-negative rod with a single polar flagellum
What is cholera?
Diarrheal disease caused by Vibrio Cholera
How is cholera transmitted?
By fecal-oral route and fecal contamination foo water
Who is primarily affected by cholera?
Adult travelers’ in the US and children in endemic areas
What is the mechanism of vibrio cholera?
Attach to epithelial cells and release cholera toxin
What is the toxin associated with cholera?
Choleragen
What is the clinical presentation of a person infected with cholera?
Abrupt onset of watery diarrhea (rice water diarrhea)
How can cholera cause death?
From dehydration
What would a microscopic exam of stool show if the patient has cholera toxin?
Curved rods with fast darting movements and NO leukocytes
What organism is involved with ingestion of uncooked seafood?
Vibrio parahaemolyticus
*leading cause of diarrhea in Japan
What is the shape of Campylobacter Jejuni?
Gram-negative rod that has curved single polar flagellum
Where is campylobacter jejuni found?
Wild and domestic animals and poultry from fecal-oral route via contaminated water
Unpasteurized milk
What is the clinical presentation of a patient infected with campylobacter jejuni?
Start: Fever and headache
After a day: Abdominal cramps and bloody, loose diarrhea
What is the most common organism to cause duodenal ulcers?
Helicobactor pylori
*second leading cause of stomach ulcers
What diseases are associated with Helicobactor pylori?
Duodenal and gastric ulcers
Gastritis
What kind of bacteria makes up 99% of the normal flora in our intestinal tract?
Obligate anaerobic gram-negative rods with the family Bacteroidaceae
What are the characteristics of Bacteroides fragilis?
Gram-negative bacteria
Does NOT contain lipid A
No endotoxin
What situation may Bacteroides fragilis become present?
Bullet tears into the intestine, seat belt laureates the intestine in a car wreck, abdominal surgery performed with bowel penetration, intestine ruptures
Then the bacteria goes into the peritoneal cavity
What is formed when Bacteroides fragilis enters the peritoneal cavity?
Abscesses
What are the components of an abscess?
Bacteria, white cells, and dead tissue
Where does Bacteroides melaninogenicus normally live?
Mouth, vagina, intestine
What disease is associated with Bacteroides melaninogenicus?
Necrotizing anaerobic pneumonia from aspiration of lots of sputum from the mouth causing periodontal disease
What diseases are associated with Fusobacterium?
Periodontal disease, aspiration pneumonia, abdominal and pelvic abscesses, and otitis media
What are the 2 gram-positive cocci anaerobes?
Peptostretococcus and Peptococcus
Where are Peptostretococcus and Peptococcus normally found?
Flora of the mouth, vagina and intestine
