Gram (+) bacilli - Sketchy Copy Flashcards
Bacillus, Clostridium, Corynebacterium, Listeria
Bacillus anthracis
lab tests
King Anthra’s Axe
Large gram (+) rods in _c_hains
Obligate Aerobe
ELISA of Anti-PA IgG
Spore forming
Capsulated with Poly-D glutamate
Bacillus anthracis
VF
King Anthra’s Axe
EF (edema factor) toxin:
Increases cAMP intercellularily → fluid goes to extracellular space → edema → inhibits host defenses and prevents phagocytosis.
LF (lethal factor) toxin:
Exotoxin that acts as portease and cleaves MAP kinase (a signal transduction protein resposible for cell growth) → Necrosis and Black Eschar (with erythematous ring)
Bacillus anthracis
GI anthrax
King Anthra’s Axe
Gi anthrax - Ingestion of Spores
Ulcers, Messenteric LAD, Abdominal Pain, Vomiting, Edema and Sepsis
Bacillus anthracis
Cutanoeus anthrax
King Anthra’s Axe
Cutanoeus anthrax - Soil Spores germinate on skin
Painless papules, Ulcers with vesicles and Eventually Necrosis
Bacillus anthracis
Pulmonary anthrax
King Anthra’s Axe
Pulmonary anthrax (AKA Wool Sorters Disease)
-Spores get into wool and hide, and people inhale the spores when the animal is handled.
Pulmonary anthrax → can move to mediastinal lymph node → hemorrhagic mediastianitis
Widened mediastinum seen on chest xray
Bacillus anthracis
treatment
King Anthra’s Axe
fluoroquinolone or doxycycline
Bacillus cereus
Treatment
King Anthra’s Axe
Self-limiting
Bacillus cereus
Food Poisoning + Other Pathogenesis
King Anthra’s Axe
Emetic Form - Short incubation: up to 6Hrs (Rice)
Heat Stable Enterotoxin-Emetic Toxin
Diarrheal Form - Long Incubation: up to 16Hrs (Meat)
Heat Labile Enterotoxin - Activates Adenylate Cyclase
Wound Infection
Bacillus cereus
Biochemical And General Features
King Anthra’s Axe
Obligate Aerobe, Gram Positive Rod and Spore forming
Pilli and No Capsule
PLC+ - Egg Yolk Medium
Beta Hemolytic - Blood Agar
Clostridium tetani
lab tests
Rhesus Research Revolution
Mostly Clinical Diagnosis from Signs - Spastic Paralysis, Risus Sardonicus, Opisthotonus.
(Quick analysis is needed so no culturing)
Clostridia Genus: gram (+) bacilli, Obligate Anaerobe, Spore forming
Clostridium tetani
Immidate Treatment
Rhesus Research Revolution
Passive immunization- anti-toxin (Human Tetanus Immunoglobulin, TETIG)
Can also give DTP if not vaccinated (if vaccinated 10 years)
Clostridium tetani
MOA
Rhesus Research Revolution
Spores in dirt enter through puncture wounds and vegetate in wound site, releasing tetanus toxin which travels retrograde through the motor axons to the spinal cord.
* Tetanus toxin cleaves SNARE and inhibits exocytosis of the NT (GABA and glycine) into the synapse or Renshaw cells.
Inhibited GABA and glycine → uncontrolled firing of the motor neurons → spastic paralysis
Renshaw cells sense over activity of nearby motor neurons and attempt to fire to inhibit the motor neurons by releasing GABA and glycine which are inhibited leading to spasm.
Clostridium tetani
signs and symptoms
Rhesus Research Revolution
Spastic paralysis leading to rigidity
Rhesus Sardonicus (to grin evilly), with lock jaw.
Opisthotonos - Arching back
Clostridium tetani
Vaccines
Rhesus Research Revolution
DTaP vaccine
Given with diphtheria and pertussis
It is a Toxoid Vaccine (toxin conjugated to protein)
Antibody response is to the toxin (not the organism)
Clostridium botulinum
Immidate Treatment
Robotulism
Passive immunization- polyvalent (serotypes A-G) antitoxin serum
Clostridium botulinum
lab tests
Robotulism
Isolation of Toxin - ELISA
Toxin detection by Mouse Inoculation with patient serum
Clostridia Genus: gram (+) bacilli, Obligate Anaerobe, Spore forming
Clostridium botulinum
MOA
Robotulism
Improper canning of food → C. botulinum grows in the anaerobic environment → produces heat stable toxin (a protease)
Cleaves SNARE protein (sim. to tetany toxin) but attacks the motor neurons that release ACh → inhibiting motor neuron release → flaccid paralysis
Toxin is unable to cross the BBB → only the peripheral nervous system
Clostridium botulinum
signs and symptoms
Robotulism
Flaccid paralysis
Descending paralysis (opposite of Guillen barre)
Multiple people
Early symptoms include ptosis (droppy eyes) and diplopia (double vision)
*“Floppy baby syndrome”
Clostridium botulinum
Source of toxin:
Babies vs. Adults
Robotulism
Adults:
Get the toxin by ingestion of pre-formed antigen from improperly canned foods.
Babies:
Get the toxin by ingestion of spores. (*HONEY!!!)
Babies lack robust flora in the gut to out compete C. botulinum → C botulinum will colonize → toxin produced → Floppy baby syndrome
Clostridium difficile
lab tests
Field trip to the chocolate factory
Assay to detect TOXIN in stool - ELISA
Culture on CCFA Medium (Cycloserin-Cefoxine Fructose Agar) - Selective for C. Difficle = Colonies are gray with Barnyard Smell
Clostridia Genus: gram (+) bacilli, Obligate Anaerobe, Spore forming
Clostridium difficile
VF
Field trip to the chocolate factory
2 exotoxins:
Exotoxin A: Binds to the brush border of intestine → causes inflammation, cell death, and watery diarrhea.
Exotoxin B: disrupts cytoskeleton integrity by depolymerizing actin → enterocyte death and necrosis → Yellow grey exudate forms pseudomembrane that covers the colonic mucose (a pseudomembranous colitis)
Clostridium difficile
source
Field trip to the chocolate factory
Caused by poorly washed hands (Nosocomial diarrhea) transfering spores
or
Antibiotics (Clindamycin) wiping out normal flora allowing C. difficile to colonize then create the toxins.
Clostridium difficile
treatment
Field trip to the chocolate factory
Oral Vancomycin
Metronidazole
Corynebacterium diphtheria
lab tests
Corazon de la Corrida (Heart of the bullfight)
gram (+) bacilli
Neisser Stain: Club shaped and y or v shaped with Metachromatic granules that Yellow body and Purple edges
Tellurite Media (with Glycerin, Blood and Cysteine) - Black with Garlic Smell (also Loeflers media)
Eleks test: in-vitro assay w/ antitoxin onit to determine if toxic or non-toxic strain
Corynebacterium diphtheria
MOA
Corazon de la Corrida (Heart of the bullfight)
Found in throat and tonsil, transmitted by respiratory droplets.
2 subunits A and B (A is active and B is binding)
Toxin causes ribosylation of EF2 (elongation factor) → inhibits ribosome function → inhibits protein synthesis → cell death
Leads to pseudomembranous exudate in oral pharynx
Will damage myelin of nerve fibers → neuropathy
Corynebacterium diphtheria
signs and symptoms
Corazon de la Corrida (Heart of the bullfight)
* Immigrants most likely to get C. diphtheria
Can cause airway obstruction and lymphopathy → * bulls neck (thickening of the neck)
Myocarditis like arrhythmias and heart block (lethal effect).
Neuropathy from damaged myelin.
Corynebacterium diphtheria
Vaccines
Corazon de la Corrida (Heart of the bullfight)
DTaP vaccine
Given with tetanus and pertussis
It is a Toxoid vaccine
Listeria monocytogenes
lab tests
Santa’s List
gram (+) bacilli, Catalase (+)
CAMP Test+ (like Agalactiae)
ß hemolytic in Cold Enrichment
PFGE Pulsed feild Gell Electrophoresis / Phage Typing
ELISA - Serological Types Ia/Ib/IVb
Listeria monocytogenes
MOA
Santa’s List
Facultative Intracellular: (“Actin Rocket”)
Rapidly polymerizes actin along the cell wall allowing it to move quickly inside the cell.
Extracellular:
Tumbling motility using flagella
Listeria monocytogenes
Source
Santa’s List
Listeria survives AND multiplies in near freezing temperatures and can contaminate food even if refrigerated.
* Milk and cheese
Listeria monocytogenes
Pregnancy
Santa’s List
Pregnant women are more likely to get listeria then anyone else. (adults over 60 also high risk)
May lead to termination or disease in the newborn.
Newborns can get meningitis from the mom.
Listeria monocytogenes
treatment
Santa’s List
Ampicillin
Clostridium Perfringens
Food Poisoning
Private Ringen’s Motorcycle Crash
Reheated Meat Dishes - Slow Unset, 8-24 Hours
Self-limiting-Non Inflammatory - Wattery Diahrrea
Clostridium Perfringens
Gas Gangrane
Private Ringen’s Motorcycle Crash
Aka Clostridial Myonecrosis: Fever, Tachycardia, Diaphoresis, Pallor - High Mortality if Untreated
Clostridium Perfringens
Other Toxins apart from α toxin
Private Ringen’s Motorcycle Crash
β Toxin - Necrotizing Activity in the Intestine
ε Toxin** - Enterotoxin that increases **vascular permeability of GI
Iota Toxin - Both ε and β Toxin Manifestations
Clostridium Perfringens
α Toxin
Private Ringen’s Motorcycle Crash
- Spores Germinate 1-3 Days
- Mature Form Produces α Toxin (PLC/Lecithinase)
- Lysis of RBCs, WBCs and Endothels
- Massive Hemolysis, Tissue Death and Hepatotoxcity
Clostridium Perfringens
Transmission and Classification
Private Ringen’s Motorcycle Crash
Transmitted by Food** or **Trauma**: **Military/Motorcycle Accidents
Classified - A to E by Toxins Composition
Clostridium Perfringens
Biochemical Properties
Private Ringen’s Motorcycle Crash
Obligate Anaerobe (ddx from Bacillus)
Spore Forming
Lecithinase Positive
Gas Producer - CO2, H2S, CH4
Capsule and Invasion Proteases
Clostridium Perfringens
General Features
Private Ringen’s Motorcycle Crash
Gram Positive Rod (large)
Habitat - Soil (Sometimes even in human Normal Flora)
Clostridium Perfringens
Diagnosis
Private Ringen’s Motorcycle Crash
Double Hemolysis Zone: α and β Hemolysis
Nagler’s Medium - Egg yolk plate with Anti-α Toxin showing PLC activity.
(Specimens - Pus, Necrotic Tissue and Blood)
Clostridium Perfringens
Treatment
Private Ringen’s Motorcycle Crash
Penicilin G - High Dose
Amputation or Hyperbaric Chamber if Gangrane
Constant Surgical Intervention to prevent anaerobic conditions for infection
