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Bacillus, Clostridium
What are two genera of bacteria that are considered as spore forming gram positive bacteria?
Cells arranged in long chains, Central spores
Morphology of Bacillus spp. based on cell structure?
Aerobic, Hemolysis in B. cereus, Gelatin Liquefied, Inverted tree in gelatin stabs
What are four characteristics of the culture morphology of Bacillus spp.?
Saprophytic - prevalent in soils, water, air, and vegetation
Bacillus subtilis is described to be ___ based on its usual habitats
Bacillus thuringiensis
Bacillus species that is an insect pathogen
Herbivores
Bacillus anthracis primarily affects what kind of consumers?
Middle East, Africa, Central America
What are three areas wherein B. anthracis is endemic?
Via contact with diseased animals, 95% cutaneous, 5% inhalation of spores
How do humans get infected by B. anthracis?
Mouth
What is the portal of entry of B. anthracis in animals?
TRUE
T/F: Bacillus anthracis primarily affects herbivores
FALSE
T/F: Bacillus anthracis primarily affects carnivores
GI Anthrax
What kind of anthrax is rare among humans?
Woolsorter's Disease
Pulmonary anthrax is also known as?
Endospores, Capsule (poly-D-glutamic acid), Exotoxins (protective antigen, edema factor, lethal factor)
What are the 3 pathogenesis or virulence factors of B. anthracis?
FALSE
T/F: The virulence factors of B. anthracis are endotoxins, capsule made of poly D glutamic acid, and exotoxins
TRUE
T/F: The virulence factors of B. anthracis are endospores, capsule made of poly D glutamic acid, and exotoxins
Poly-D-Glutamic Acid
The capsules of B. anthracis are unique in a sense that they are the only bacteria whose capsules are made of?
Prevents phagocytosis
What is the function of the capsule of B. anthracis
Protective antigen (PA)
[BA] Identify the exotoxin: Promotes entry of EF, similar to a B subunit
Edema Factor (EF)
[BA] Identify the exotoxin: Active A subunit, impairs neutrophil function causing massive edema
Lethal Factor (LF)
[BA] Identify the exotoxin: Stimulates release of tumor necrosis factor
pXO1 and pXO2
The expression of the virulence factors of B. anthracis are coded for by what plasmids?
Increase of temperature to 37 deg C, Certain CO2 concentrations; When spores enter the host
What are the 2 conditions that regulate pXO1 and pXO2? Where are these conditions met?
pXO1 and pXO2 plasmids are only activated when they go in the host, so the virulence factors can only be expressed upon entry to suitable tissue
How does expression of virulence factors in B. anthracis get limited to inside the host?
Cutaneous (painless, black vesicles) , Pulmonary, GI (abdominal pain, vomiting, bloody diarrhea)
What are three categories of clinical findings for B. anthracis?
Ciprofloxacin, Doxycycline, Raxibacumab (pulmonary), Vaccines
What are four treatments for B. anthracis infections?
TRUE
T/F: B. anthracis must be quickly detected
FALSE
T/F: B. anthracis have long detection times
Gram stain, culture, serology; PCR of nasal swab
What are 2 means for diagnostics of B. anthracis?
3 spores
The PCR swab of B. anthracis is highly sensitive as a positive infection can be identified with what minimum number of spores?
Motile, non-encapsulated
Describe the cell morphology of B. cereus
When spores are ingested
How does B. cereus cause food poisoning?
Endospores, Enterotoxins (Heat-labile, Heat-stable)
What are the two pathogenesis or virulence factors of B. cereus?
Heat-labile toxin
[BC] What virulence factor: Causes nausea, abdominal pain, and diarrhea
Heat-stable toxin
[BC] What virulence factor: Causes nausea and vomiting, limited diarrhea
Food poisoning: nausea, vomiting, diarrhea; Bacteremia / endocarditis (rare)
What are 2 clinical findings for B. cereus infections?
Vancomycin, Clindamycin, No treatment for food poisoning (spores cause infection, not actual bacteria)
What are the treatments for B. cereus?
Culture from contaminated food
What is the diagnostic method for B. cereus?
Rod-shaped, Central, subterminal, terminal spores, Peritrichously-flagellated
What is the morphology in terms of cell structure of Clostridium spp.? Cell shape, Spore locations, Flagella location
Anaerobes (Few Aerotolerant), Grows well on blood-enriched media, B-hemolytic
What is the morphology in terms of culture of Clostridium spp.? Oxygen requirement, Grows well in what media, hemolysis
Soil, Canned or Bagged Food, Smoked Fish, Honey
What are four examples of food that C. botulinum is known to inhabit?
Flaccid paralysis
What kind of paralysis does C. botulinum cause?
Adult botulism, Infant botulism, Wound botulism
What are three types of botulism caused by C. botulinum?
Infant botulism
Infants below 2 years old are not recommended to take honey due to the risk of?
Constipation for 2-3 days, then dysphagia
How does foodborne infant botulism present itself in infants?
Neurotoxin that inhibits the release of acetylcholine from peripheral nerves
Describe the pathogenesis of the toxin released by C. botulinum?
Upon death of bacterium
When are C. botulinum toxins released?
GI symptoms, Cranial nerve palsies, Muscle weakness, Respiratory paralysis
What are four clinical findings under foodborne botulism?
FALSE
T/F: In foodborne botulism, only facial muscles are known to be affected
TRUE
T/F: Foodborne botulism affects lung muscles.
Constipation, Flaccid Paralysis
What are two clinical findings under infant botulism?
Similar to FB but without the GI symptoms
Describe wound botulism as a clinical finding?
Bot immunoglobulin - IV (BIG IV) is human derived and has less complications so it is given to infants, BIG-N given to adults is equine derived
What is the main difference between BIG-IV and BIG-N as treatment for C. botulinum infection?
Antitoxin
For foodborne and wound botulism, what is a common treatment given?
BIG-IV
What kind of treatment is specially given for infant botulism?
Surgical debridement
What kind of treatment is specially given for wound botulism?
Penicillin
Antibiotic of choice for C. botulinum
Risus sardonicus
Symptom seen in late cases of C. tetani characterized by locked jaw
Skin trauma or punctured by sharp object with C. tetanus
How is C. tetani infection acquired?
Mortality
What usually follows after Risus sardonicus is observed in a patient with C. tetani infection?
Tetany
Sustained contraction of skeletal muscles
Tetanospasmin, C. tetani
Toxin that causes sustained contraction of skeletal muscles + what organism releases it?
Renshaw cell interneurons, GABA and glycine, inhibitory, low
Fill in the blank: C. tetani toxins inhibits release of ____, preventing the release of ___ which are ___ neurotransmitters, leading to ___ frequency impulses to the muscle cells
gamma-aminobutyric acid
What does GABA stand for?
Tetanus toxoid
What is a component of the DTaP vaccine that serves as a treatment against C. tetani?
Human tetanus immune globulin
What is the antitoxin against C. tetani?
Metronidazole, Penicillin
What are antibiotics for C. tetani?
Subterminal endospores
What is helpful for identifying C. tetani versus other Clostridium species?
Crepitus
moist spongy appearance of skin, cracks when pressed
Clostridium perfringens
Clostridium species that causes gas gangrene
Clostridium perfringens
Clostridium species that is rampant and one of the primary causes of death in soldiers before penicillin
Anaerobic, Produces gas
Describe C. perfringens in terms of oxygen requirement and gas production
Alpha toxin - lecithinase
What is a toxin virulence factor for C. perfringens
Cellulitis (wound infection), Clostridial myonecrosis, Diarrheal illness
What are 3 clinical findings for C. perfringens? 2 skin based and 1 enteric
Cellulitis
Clinical finding in C. perfringens characterized by exposure of necrotic skin and crepitus
Clostridial myonecrosis
More severe form of cellulitis, when untreated it can reach the bones
Watery Diarrhea
What kind of diarrhea is observed in C. perfringens infections?
Penicillin
What antibiotic is used for C. perfringens?
Hyperbaric oxygen
What is a treatment unique for C. perfringens infections?
Pseudomembranous colitis (antibiotic associated)
What infection or clinical finding does C. difficile cause?
Taking a broad spectrum drug for a long time wipes the gut of microflora, so the opportunistic C. difficile takes over
How does C. difficile cause antibiotic-associated pseudomembranous colitis?
Red and inflamed mucosa, with areas of white exudates
For antibiotic associated pseudomembranous colitis, what can be observed with the intestinal mucosa?
Toxin A, Toxin B, Binary Toxin CDT
What are 3 toxins that serve as virulence factors of C. difficile?
Toxin A causes diarrhea, Toxin B is cytotoxic to colonic cells
How are C. difficile Toxins A and B different from each other?
15 to 20 times
The binary toxin CDT in C. difficile (2002) produces how many times more toxins?
Discontinue antibiotics, Colonoscopy, Fidaxomycin, Vancomycin, Metronidazole, Fecal Transplantation
What are treatments recommended for C. difficile infections?
PCR for toxin detection, EIA for antigens to toxins A and B
What are 2 recommended diagnostics for C. difficile?
Opportunistic Pathogen
Once gut microflora is gone, C. difficile take advantage of lessened competition for nutrients. With this, we can say that C. difficile is what kind of pathogen?
Patients with loose diarrhea for more than 3 days
For C. difficile, what kind of patients do we usually recommend stool PCR for?
Coccobacillus or pleiomorphic rods, Club shaped
Morphology of C. diphtheriae
Facultative anaerobe, Catalase positive, Non motile
Describe the following culture characteristics of C. diphtheriae: oxygen requirement, catalase reaction, motility
Respiratory droplets from carrier
How is C. diphtheriae infection usually acquired?
TRUE
T/F: Corynebacterium diphtheriae is the only known species of the Corynebacterium genus
FALSE
T/F: Corynebacterium diphtheriae is the most prominent of the Corynebacterium genus, but there are other species
Throat is colonized first, then produces toxins in pharynx, then toxins reach brain and heart
Describe how C. diphtheria colonizes the body
Strep Throat
C. diphtheria infections are easy to confuse with?
C. diphtheria have grayish exudates and thicker coverings on throat
If we are presented with a patient with throat exudates, how do we determine if these are caused by Streptococcus or C. diphtheria?
FALSE
T/F: In C. diphtheria infections, we can scrape off exudates for further testing
TRUE
T/F: In C. diphtheria infections, we use throat swabs for further testing and not exudate scrapings
fibrin, leukocytes, nec epithelial cells, and C. diphtheriae cells
In the grayish pseudomembrane formed by C. diphtheriae, what are the components?