Micr Su12 04. Notes - Gram Positive Bacilli

Front 1

Name the 7 general of Gram-positive bacilli and categorize them: endospore forming, non-endospore forming, branching

Back 1

ENDOSPORE: 1 Bacillus, 2 Clostridium. NO ENDOSPORE: 3 Listeria, 4 Corynebacterium, 5 Gardnerella. BRANCHING: 6 Actinomyces, 7 Nocardia

Front 2

1. Understand key details of the 7 different Gram-positive bacilli: basics, virulence mechanisms and infections (a summary appears at the end of these notes on pp. 11-12)

Back 2

xxx

Front 3

2. Understand the process of sporulation, the structure and properties of endospores, and the organisms that form them.

Back 3

xxx

Front 4

3. Be able to pick up on key “trigger words” for each organism (play my bacilli trigger word game after the G-ve bacilli lectures. Answers will be posted on Canvas)

Back 4

xxx (take notes in class)

Front 5

4. Learn the primary bacterial toxins used by Gram-positive bacilli and their mechanisms of action (summary of bacterial toxins is in red font on p10)

Back 5

xxx

Front 6

5. Know key culture media used to identify Gram-positive bacilli (p8)

Back 6

1 Loeffler coagulated serium medium for Corynebacteria diphtheria, 2 Potassium -tellurite medium that turns brown when C. diphtheria converts it to elemental tellurium

Front 7

Name the endospore forming bacilli (6)

Back 7

B. anthracis, B. cereus, C. tetani, C. perfringens, C. botulinum, C. difficile

Front 8

Name the non-endospore forming bacilli (3)

Back 8

L. monocytogenes, C. diphtheriae, G. vaginalis

Front 9

Name the branching bacilli (2)

Back 9

A. israelii, Nocardia

Front 10

B. anthracis: full name, the basics (1)

Back 10

Bacillus anthracis. Endospore-forming. Usually spores found in dry fields infect herbivores, which is why you can send it in the mail.

Front 11

B. anthracis: virulence factors (4)

Back 11

1 polyPEPTIDE capsule. ANTHRAX TOXINS: 1 PA, 2 LF, 3 EF.

Front 12

PA: acronym, mechanism of virulence

Back 12

protective antigen. Binds to cell and facilitates entry of LF and EF.

Front 13

LF: acronym, mechanism of virulence

Back 13

metalloprotease of MAP kinase; signals for cell death

Front 14

EF: acronym, mechanism of virulence

Back 14

Edema factor is a calmodulin-mediated adenylate cyclase. inc cAMP > membrane more permeable > cells lose water > pulmonary edema

Front 15

B. anthracis: infections (3) by body system

Back 15

SKIN: cutaneous anthrax > eschar. GI (rare): GI inflammation. INHALATION: inhalation > eaten by macrophages > carried lymph node > start eating the macrophage and then the lymph node and then produce exotoxins > hemorrhagic mediastinitis, pulmonary edema > bacteria enter bloodstream through thoracic duct > septicemia > death

Front 16

B. cereus: full name, source

Back 16

Bacillus cereus. Found in rice and vegetables. Endospore-forming.

Front 17

B. cereus: infections (2)

Back 17

1 emetic disease, 2 diarrheal disease

Front 18

emetic disease of B. cereus, pathogenesis

Back 18

From eating ENTEROTOXIN. Poorly refridgerated fried rice > bacteria eat protein in the rice > produce enterococcin > nausea, vomiting, diarrhea

Front 19

diarrheal disease of B. cereus, pathogenesis

Back 19

From eating BACTERIA. Contaminated meat > bacteria multiply in intestines > release enterotoxins > diarrhea (no vomiting).

Front 20

Clostridium: the basics

Back 20

anaerobic. Endospore-forming.

Front 21

C. tetani: full name, morphology, source, general preferred environment

Back 21

Clostridium tetani. Look like a tennis racket due to terminal endospores. From soil. Prefers low-oxygenated tissues.

Front 22

C. tetani: characteristic infection

Back 22

Incubation of several weeks. Produce tetanus toxin > acts on anterior horn cells > retrograde transport (dynien) > destroys synaptobrevin II > prevents inhibitory nt release > uninhibited nerve impulses > death from paralysis of throat and respiratory muscles

Front 23

Name the inhibitory nt's that are blocked by tetanus. (2)

Back 23

GABA, glycine

Front 24

C. perfringens: full name, source, typical infections

Back 24

Clostridium perfringens. From soil, feces. 1 wound infection, 2 gas gangrene

Front 25

wound infection by C. perfringens: pathogenesis and course of disease

Back 25

bacteria introduced into tissue by surgery or trauma > produce toxins, gas > gas gangrene > massive tissue destruction

Front 26

food poisoning by C. perfringens, pathogenesis

Back 26

eat contaminated meat > L secretory diarrhea > resolves within 24hr

Front 27

C. botulinum: full name, source, main virulence factor.

Back 27

Clostridium botulinum. Found in soil. Produces neurotoxin.

Front 28

C. botulinum: typical infections (3)

Back 28

1 food-born botulism, 2 infant botulism (most common form in USA), 3 wound botulism, (4) SoCal botulism aka Botox

Front 29

food-born botulism by C. botulinum: pathogenesis

Back 29

poorly canned green beans > incubates 1-2 days > bacteria produce botulism toxin which blocks ACh receptors > flaccid paralysis

Front 30

infant botulism by C. botulinum: pathogenesis

Back 30

eat honey > spores grow > floppy baby syndrome > respiratory arrest

Front 31

wound botulism by C. botulinum: pathogenesis

Back 31

bacteria infect wound > flaccid paralysis

Front 32

C. difficile: full name, source, main risk factor, types of strains, virulence factors.

Back 32

Clostridium difficile. Found in soil, feces. Overgrowth due to antibiotics. Can be toxigenic or non-toxigenic. Toxins A & B.

Front 33

C. difficile: typical infections (

Back 33

C. difficile associated disease (CDAD) 1 Environmental, or 2 endogenous

Front 34

environmental C. difficile associated disease: pathogenesis

Back 34

hospital worker touches a rectal thermometer > washes hands with alcohol that does not kill spores > transmits to next pt > mild diarrhea or pseudomembranous colitis

Front 35

pseudomembranous cholitis, ssx

Back 35

abd cramping, fever, diarrhea containing blood and pus

Front 36

endogenous C. difficile associated disease: pathogenesis

Back 36

oral antibiotics > changes enteric flora > overgrowth of bacteria

Front 37

L. monocytogenes: full name, morphology, metabolism, preferred growing conditions, source (3)

Back 37

Listeria monocytogenes. Non-endospore forming. Coccobacilli. Facultative anaerobes. Can grow in wide pH, salt, and temp range, and can grow inside cells. Found in GI tracts of animals, soil, food (deli items like cheese and meats)

Front 38

gastroenteritis due to L. monocytogenes: pathogenesis

Back 38

enters intestines > adheres to epithelial cells via E-cadherin > taken up by intestinal cells > uses listeriolysin to poke holes in phagosomes > moves to adjacent cells > infection is usually asymptomatic

Front 39

L. monocytogenes: typical infections (3)

Back 39

1 mild gastroenteritis in summertime, 2 septicemia of fetuses, 3 meningitis in immunocompromised renal transplant patients

Front 40

C. diphtheriae: full name, morphology, metabolism, source, mode of transmission

Back 40

Corynebacterium diphtheriae. Non-endospore forming. Club-shaped. Aerobes. Found in plants, animals, human skin & mucous membranes. Transmitted by droplets or skin contact.

Front 41

C. diphtheriae: virulence factors, typical infections (2)

Back 41

diptheria toxin, aka A-B toxin. Inhibits protein synthesis in the oropharyngeal mucosa, heart, nerve cells. Typical infections: 1 respiratory diphteria, 2 cutaneous diphtheria

Front 42

Respiratory infection by C. diphtheriae: pathogenesis, clinical outcomes leading to death (2)

Back 42

incubate in oropharynx 2 days > exudative pharyngitis > dirty white pseudomembrane (can obstruct airway leading to suffocation) > toxins (not bacteria) invade into body > "bull necked" appearance, myocarditis, cardiac failure

Front 43

Cutaneous infection by C. diphtheriae: pathogenesis

Back 43

skin contact with infected person > breaks through skin > papule > chronic nonhealing ulcer > toxins invade > myocarditis, cardiac dysfunction, laryngeal nerve palsy

Front 44

G. vaginalis: full name, metabolism, source, morphology

Back 44

Gardenerella vaginalis. Non-endospore forming. Facultative anaerobe. Gram-variable cells that form "clue cells"

Front 45

clue cell, def

Back 45

vaginal epithelial cell covered in bacteria

Front 46

Bacterial vaginosis due to G. vaginalis: pathogenesis

Back 46

Usually inhibited by acidic Lactobacillus > something kills it > fishy smelling vagina that gets worse with intercourse (semen is basic)

Front 47

A. israelii: full name, metabolism, source

Back 47

Actinomyces israelii. Branching bacillus. Anaerobic. Found in mucous membranes (gingiva, vagina).

Front 48

endogenous infection of A. israelii: pathogenesis

Back 48

trauma (tooth extraction, IUD) compromises tissue blood flow > bacteria grow with no respect for anatomic boundaries > lump, abscess (possibly brain), sinus formation with hard yellowish microcolonies > may be misdiagnosed a sa neoplasm

Front 49

Nocardia: metabolism, morphology, source

Back 49

Branching bacilli. Aerobic. Filaments that break into rods. Found in soil.

Front 50

Nocardia: typical infections

Back 50

1 pulmonary nocardiosis, 2 cutaneous or subcutaneous infection, 3 brain abscess

Front 51

pulmonary nocardiosis or brain abscess due to Nocardia: pathogenesis

Back 51

inhalation of bacteria by immunocompromised individual > spreads to organs such as brain > can cause a brain abscess

Front 52

cutaneous infection due to Nocardia: pathogenesis

Back 52

traumatic implantation of bacteria > abscess

Front 53

calcium dipicolinate: fxn, producing cell genera

Back 53

calcium dipicolinatedehydrates nucleic acids. Produced by Bacillus, Clostridium.

Front 54

Name the stain used to detect endospores (and the counter-stain used).

Back 54

Schaefer-Fulton endospore stain w/ malachite green. Counter-stain: safranin.

Front 55

Name the layers of an endospore, innermost to outermost, starting with DNA. (5)

Back 55

1 core (DNA w/ calcium dipicolinate), 2 cytoplasmic membrane, 3 spore wall (peptidoglycan), 4 cortex (less cross-linked peptidoglycan), 5 keratin spore coat

Front 56

Name the organism with a polyPEPTIDE capsule. How do the effects of this differ from those of a normal capsule? (2)

Back 56

polypeptide capsule is 1 immunogenic, 2 antiphagocytic

Front 57

CLINICAL APPLICATION: A pt presents with a widened mediastinum on X-ray. Which organism?

Back 57

Indicative of hemorrhagic mediastinitis due to B. anthracis, a Gram-positive bacillus.

Front 58

toxins produced by C perfringens? (2)

Back 58

alpha toxins (aka phospholipase C, destroys membranes), theta toxins (destroys

Front 59

Name the Gram-positive bacilli that cause food poisoning and the type of food.

Back 59

B. cereus (fried rice if emetic, contaminated meat if diarrheal), C. perfringens (reheated meat dishes), C. botulinum (poorly canned beans, honey NOTE: only food poisoning that is neurotoxic)

Front 60

Toxins produced by C. difficile, mechanisms (2)

Back 60

Toxin A: intestinal fluid secretion, mucosal injury. Toxin B: depolymerizes actin.

Front 61

Organisms covered by Tdap?

Back 61

Corynebacterium diphtheriae, Clostridium tetani

Front 62

CLINICAL APPLICATION: How can thrichomonas vaginalis and Gardnerella vaginalis be distinguished (ssx are similar)?

Back 62

wet mount - if clue cells are present, it's G. vaginalis

Front 63

From eating ENTEROTOXIN. Poorly refridgerated fried rice > bacteria eat protein in the rice > produce enterococcin > nausea, vomiting, diarrhea

Back 63

emetic disease of B. cereus, pathogenesis

Front 64

From eating BACTERIA. Contaminated meat > bacteria multiply in intestines > release enterotoxins > diarrhea (no vomiting).

Back 64

diarrheal disease of B. cereus, pathogenesis

Front 65

bacteria introduced into tissue by surgery or trauma > produce toxins, gas > gas gangrene > massive tissue destruction

Back 65

wound infection by C. perfringens: pathogenesis and course of disease

Front 66

eat contaminated meat > L secretory diarrhea > resolves within 24hr

Back 66

food poisoning by C. perfringens, pathogenesis

Front 67

poorly canned green beans > incubates 1-2 days > bacteria produce botulism toxin which blocks ACh receptors > flaccid paralysis

Back 67

food-born botulism by C. botulinum: pathogenesis

Front 68

eat honey > spores grow > floppy baby syndrome > respiratory arrest

Back 68

infant botulism by C. botulinum: pathogenesis

Front 69

bacteria infect wound > flaccid paralysis

Back 69

wound botulism by C. botulinum: pathogenesis

Front 70

hospital worker touches a rectal thermometer > washes hands with alcohol that does not kill spores > transmits to next pt > mild diarrhea or pseudomembranous colitis

Back 70

environmental C. difficile associated disease: pathogenesis

Front 71

abd cramping, fever, diarrhea containing blood and pus

Back 71

pseudomembranous cholitis, ssx

Front 72

oral antibiotics > changes enteric flora > overgrowth of bacteria

Back 72

endogenous C. difficile associated disease: pathogenesis

Front 73

enters intestines > adheres to epithelial cells via E-cadherin > taken up by intestinal cells > uses listeriolysin to poke holes in phagosomes > moves to adjacent cells > infection is usually asymptomatic

Back 73

gastroenteritis due to L. monocytogenes: pathogenesis

Front 74

incubate in oropharynx 2 days > exudative pharyngitis > dirty white pseudomembrane (can obstruct airway leading to suffocation) > toxins (not bacteria) invade into body > "bull necked" appearance, myocarditis, cardiac failure

Back 74

Respiratory infection by C. diphtheriae: pathogenesis, clinical outcomes leading to death (2)

Front 75

skin contact with infected person > breaks through skin > papule > chronic nonhealing ulcer > toxins invade > myocarditis, cardiac dysfunction, laryngeal nerve palsy

Back 75

Cutaneous infection by C. diphtheriae: pathogenesis

Front 76

Usually inhibited by acidic Lactobacillus > something kills it > fishy smelling vagina that gets worse with intercourse (semen is basic)

Back 76

Bacterial vaginosis due to G. vaginalis: pathogenesis

Front 77

trauma (tooth extraction, IUD) compromises tissue blood flow > bacteria grow with no respect for anatomic boundaries > lump, abscess (possibly brain), sinus formation with hard yellowish microcolonies > may be misdiagnosed a sa neoplasm

Back 77

endogenous infection of A. israelii: pathogenesis

Front 78

inhalation of bacteria by immunocompromised individual > spreads to organs such as brain > can cause a brain abscess

Back 78

pulmonary nocardiosis or brain abscess due to Nocardia: pathogenesis

Front 79

traumatic implantation of bacteria > abscess

Back 79

cutaneous infection due to Nocardia: pathogenesis