Kirn - Gram Negative Rods Flashcards
What do HOK stand for and what are they used for?
H-flagella
O-LPS
K-Kapsule
Used for stereotyping to describe the different characteristics of the bacteria
What is the name and difference between the three types of intestinal infections?
1) non inflammatory - bacteria in lumen
2) inflammatory - bacteria invade wall
3) penetrating - bacteria beyond wall
What kind of culture do u use to cholera
TCBS - stool sample will show up as green/yellow
Mechanism of action of cholera vibrio
A unit adds ADP-ribose group to Gs to permenantly activate it
Gs stimulates adenylyl Cyclase
This causes high levels of cAMP
CFtR pumps a lot of chlorine out of cell into lumen
This causes osmotic inflow of water
ETEC
Common cause of travelers diarrhea.
Two exotoxins - acid labile and acid stable
Acid labile - like cholera, causes increased cAMP
Acid stable - causes increased cGMP
“eL Agua del San Gabriel”
EPEC
Type III secretion
- causes brush border to disappear in intestine and pedestals to form via that whole mechanism in the video
- Basically the bacteria comes down and the brush border just dissapears to make way for landing. The pili attach to the epithelial lining allowing for a smooth landing. A tube like structure comes down and spits proteins into the epithelium which then come back up and live in the epithelial lining. They built actin filaments that become very long and push up on the epithelial lining. The original microbe then has these pedestals that cup the top of the proteins and pull it up.
Shigella
Painful, bloody, low volume stools with WBC and mucus
- transocytosis by M cells –> invade enterocytes via type III system —> lyses phagocytic vacuole so that the enter cytosol –> actin polymerization causes actin tail to form that pushes bacteria through palmsa membrane into adjacent tails
Shiga toxin
A subunit cleaves RNA of large ribosomal subunit causing the ribosome to be inactive
- causes hemolytic uremic syndrome (HUS)- micro vascular damage in the kidneys that cause red cell lysis
EHEC
Shiga like toxin Causes HUS Causes bloody diarrhea Predominant serotype is O157:H7 Sorbitol it from undercooked meat
Non-typhoidal salmonella
Get it from meat and eggs
Can get it from pet reptiles
Causes gastroenteritis
Exit M cells and invade enterocytes to multiply locally
Induce apoptosis via type III system
Non bloody diarrhea, fever, nausea, vomiting
Campylobacter jejuni
Association with guillan barre
Gullwing morphology
Transmitted from chicken
Helicobacter pylori (H pylori)
Causes peptic ulcers
Resides below mucus layer of stomach
Has urease which converts urea to ammonia
Diagnosis: gastric biopsy, breath test with labeled carbon to test for ammonia, stool antigen assay
Typhoidal salmonella
Has capsule
Penetrate intestine via m cells
May be cultured from bone marrow
Can establish chronic state in gall bladder
P-fimbrae
Allows E. coli to adhere to bladder epithelium
Additional things that E. coli causes
K1 causes neonatal meningitis
S fimbrae adheres to endothelium and choroid plexus
What are the common nosocomial infections?
Enterobacter
Klebsiella
Serratia
“Sloan Kettering entrance”
Haemophilus influenzae
Chocolate agar
- with NAD and hemin
Common in upper respiratory
Virulence factor - Type b capsule, IgA capsule, iron acquisition mechanisms
Causes otitis media, epiglottitis, pneumonia, meningitis, septic arthritis
Hib vaccine
Vaccine for haemophilus influenza that is given to all kids at 2 months of age.
Treatment for haemophilus influenzae
Ceftriaxone or other 3rd gen cephalosporins
Haemophilus ducreyi
School of fish gram stain morphology
Chancroid - genital infection that spreads to the lymph node
Bordatella pertussis
Small colonies in blood agar
Usually use NAAT for diagnosis
Small colonies on blood agar
Causes whooping cough
Long lasting disease
Virulence factors - filamentous hemagglutinin (binds integrins on ciliated epithelial cells), fimbrae phase variation, BrkA protein (causes complement resistance). Tracheal toxin, adenylate Cyclase toxin, pertussis toxin.
Prevention - DTaP vaccine ( diphtheria, pertussis, acellular pertussis)
Legionella pneumophila
Respiratory infection usually coming from aerosol for a bad water supply.
Pontiac fever is milder form
Needs BCYE agar with iron and cysteine, highly fastidious
Usually use Urine Ag test to detect
Brucella
From livestock and dairy
Systemic febrile illness
Pasteurella multocida
Normal oral flora of domestic animals such as cats and dogs.
- causes snuffles in rabbits
- infections associated with animal bites
- causes soft tissue Infection
Francisella tularensis
Transmission from wild animals, usually rabbits.
- low infectious dose so a irks to la workers
Causes:
ulceroglandular - ulcer at inoculation site, lymphadenopathy
Oculoglandular - eye is site of inoculation, lymphadenopathy
Oral or pharyngeal - contaiminated food/water
Respiratory infection - aerosol transmission
Yersinia Pestis
Cause of bubonic plague
Transmitted from rodents to humans by flee bite
Prairie dog
Flee bites sick animal and then the blood clots in its stomach. Upon biting a human the flea regurgitates the blood into us.
Causes bubous, enlarged lymph nodes.
Bipolar staining that looks like a safety-pin using Wayson stain
Can get into lungs and cause “pneumonic plague” which can lead to human to human transmission.
Has a capsule
Pseudomonas aeruginosa
Present in soil, water, vegetation Forms biofilms Siderosphores Smell like grapes/OJ - community acquired infection - hot tub folliculitis - otitis externa - more common in burn victims and incubated patients - in CF patients you will see chronic respiratory infection
What does P. Auruginosa look like when plated?
Produces greenish pigment that looks slimy due to the presence of an extracellular polysaccharide capsule.
