[BIO 120.3] Q1: Gram Positive Rods - Bacillus and Clostridium (Spore Forming), Corynebacterium and Listeria (Non Spore Forming)

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?