Fa: Microbiology - Clinical Bacteriology

Front 1

Which bacteria are G+ with branching filaments? How do you distinguish them?

Back 1

- Actinomyces (anaerobe, not acids fast)
- Nocardia (aerobe, acid fast)

Front 2

Which bacteria are G+ rods? How do you distinguish some of them?

Back 2

- Clostridium (anaerobe)
- Corynebacterium
- Listeria
- Bacillus (aerobe)
- Mycobacterium (acid-fast)

Front 3

How do you distinguish the G+ cocci?

Back 3

- Catalase test
- Coagulase test
- Hemolysis

Front 4

Which bacteria are G+ and catalase +? How do you distinguish them?

Back 4

Staphylococcus (clusters)
- Coagulase +: S. aureus
- Coagulase -: Novobiocin sensitive S. epidermidis and Novobicin resistant S. saprophyticus

Front 5

Which bacteria are G+ and catalase -? How do you distinguish them?

Back 5

Streptococcus (chains)
- Distinguish based on hemolysis

Front 6

Which bacteria are G+, catalase +, and coagulase +? Organization?

Back 6

S. aureus - cocci in clusters

Front 7

Which bacteria are G+, catalase +, and coagulase -? Organization?

Back 7

Clusters of cocci:
- Novobiocin sensitive S. epidermidis
- Novobiocin resistant S. saprophyticus

"NO StRESs": NOvobiocin - Saprophyticus is Resistant and Epidermidis is Sensitive

Front 8

Which bacteria are G+, catalase -, and have partial hemolysis (green)?

Back 8

α-hemolytic Streptococcus (chains)
- S. pneumoniae
- Viridans streptococci

Front 9

Which bacteria are G+, catalase -, and have complete hemolysis (clear)?

Back 9

β-hemolytic Streptococcus (chains)
- Group A: S. pyogenes
- Group B: S. agalactiae

Front 10

Which bacteria are G+, catalase -, and have no hemolysis?

Back 10

γ-hemolytic Streptococcus (chains)
- Group D: Enterococcus - E. faecalis
- Non-enterococcus: S. bovis

Front 11

What are the types of hemolysis?

Back 11

- α-hemolysis: partial (forms green ring around colonies on blood agar)
- β-hemolysis: complete (forms clear area of hemolysis on blood agar)
- γ-hemolysis: none

Front 12

What does α-hemolysis mean? What are the types of bacteria that fall under this category?

Back 12

Partial hemolysis (green ring around colonies on blood agar)

*Streptococcus pneumoniae
- Catalase (-)
- Optochin sensitive
- Capsule
- Bile soluble (lysed by bile)

*Viridans streptococci (eg, S. mutans)
- Catalase (-)
- Optochin resistant
- No capsule
- Bile insoluble (not lysed by bile)

"OVRPS (overpass): Optochin - Viridans is Resistant; Pneumoniae is Sensitive

Front 13

What does β-hemolysis mean? What are the types of bacteria that fall under this category?

Back 13

Comlete hemolysis (clear area around colonies on blood agar)

*Streptococcus pyogenes
- Group A Strep
- Catalase (-)
- Bacitracin sensitive

*Streptococcus agalactiae
- Group B Strep
- Catalase (-)
- Bacitracin resistant

"B-BRAS: Bacitracin - group B is Resistant, group A is Sensitive"


*Staphylococcus aureus
- Catalase (+)
- Coagulase (+)

*Listeria monocytogenes
- Tumbling motility
- Meningitis in newborns
- Unpasteurized milk

Front 14

What does γ-hemolysis mean? What are the types of bacteria that fall under this category?

Back 14

No hemolysis

*Enterococcus (E. faecalis)
- Grows in bile and 6.5% NaCl
- Group D

*Non-Enterococcus (S. bovis)
- Grows in bile, not 6.5% NaCl

Front 15

What does the "on the office's "staph" retreat, there was no stress" mnemonic mean?

Back 15

Staphylococcus - NO StRESs:
Novobiocin -
- Saprophyticus is Resistant
- Epidermidis is Senstive

Front 16

What does the "overpass" mnemonic indicate?

Back 16

OVRPS:

Optochin
- Viridans is Resistant
- Pneumoniae is Sensitive

Front 17

What does the "B-BRAS" mnemonic indicate?

Back 17

B-BRAS

Bacitracin
- Group B strep are Resistant
- Group A strep are Sensitive

Front 18

Which bacteria:
- G+ cocci in clusters
- Protein A (virulence factor)

Back 18

Staphylococcus aureus

Front 19

Which virulence factor does Staphylococcus aureus use? Mechanism?

Back 19

Protein A:
- Binds Fc-IgG
- Inhibits complement activation and phagocytosis

Front 20

Where does Staphylococcus aureus colonize / infect?

Back 20

- Commonly colonizes: nose

Inflammatory Disease:
- Skin infections
- Organ abscesses
- Pneumonia (often after influenza virus infection)
- Endocarditis
- Osteomyelitis

Front 21

What does Staphylococcus aureus cause?

Back 21

Inflammatory Disease:
- Skin infections
- Organ abscesses
- Pneumonia (often after influenza virus infection)
- Endocarditis
- Osteomyelitis

Toxin-Mediated Disease
- Toxic Shock Syndrome (TSST-1)
- Scalded Skin Syndrome (Exfoliative Toxin)
- Rapid-onset food poisoning (enterotoxins)

MRSA (Methicillin-Resistant S. aureus)
- Important cause of serious nosocomial and community-acquired infections
- Resistant to methicillin and nafcillin because of altered penicillin binding protein

Front 22

What are the toxin mediated diseases of S. aureus? Toxin?

Back 22

- Toxic Shock Syndrome (TSST-1)
- Scalded Skin Syndrome (Exfoliative Toxin)
- Rapid-onset food poisoning (enterotoxins)

Front 23

What is an important cause of serious nosocomial and community-acquired infections?

Back 23

MRSA (Methicillin-Resistant S. aureus)
- Resistant to methicillin and nafcillin because of altered penicillin binding protein

Front 24

What is TSST? Mechanism of action? What does it cause?

Back 24

Toxic Shock Syndrome Toxin → Toxic Shock Syndrome
- Superantigen that binds to MHC II and T-Cell Receptor
- Results in polyclonal T-cell activation
- Presents as fever, vomiting, rash, desquamation, shock, and end-organ failure

Front 25

What predisposes to Toxic Shock Syndrome?

Back 25

Use of vaginal or nasal tampons

Front 26

Which bacteria causes rapid food poisoning? Mechanism?

Back 26

S. aureus food poisoning is due to ingestion of preformed toxin (enterotoxins)
- Short incubation period (2-6 hours)
- Enterotoxin is heat stable → not destroyed by cooking

Front 27

How does S. aureus form an abscess?

Back 27

Forms fibrin clot around itself → abscess

Front 28

Which bacteria is known for infection prosthetic devices and IV catheters? Mechanism?

Back 28

Staphylococcus epidermidis
- Produces adherent biofilms to these medical devices

Front 29

Characteristics of Staphylococcus epidermidis?

Back 29

Catalase (+), Coagulase (-)
- Infects prosthetic devices and IV catheters by producing adherent biofilms
- Component of normal skin flora
- Contaminates blood cultures
- Novobiocin sensitive (No StRESs)

Front 30

Which bacteria are the first and second most common cause of uncomplicated UTI in young women?

Back 30

1. E. coli
2. Staphylococcus saprophyticus

Front 31

Characteristics of Staphylococcus saprophyticus?

Back 31

Catalase (+), Coagulase (-)
- 2nd most common cause of uncomplicated UTI in young women
- Novobiocin resistant (No StRES)

Front 32

What does Streptococcus pneumoniae cause?

Back 32

Most common cause of:
- Meningitis
- Otitis media (in children)
- Pneumonia
- Sinusitis

MOPS
(MOPS also stands for Most are Optochin Sensitive)

Front 33

Characteristics of Streptococcus pneumoniae?

Back 33

Catalase (-), α-hemolysis (partial)
- Lancet-shaped
- G+ diplococci
- Encapsulated (no virulence w/o capsule)
- IgA protease
- Optochin sensitive = OVRPS)

Front 34

What are the signs of Streptococcus pneumoniae?

Back 34

- Rusty sputum
- Sepsis in sickle cell anemia
- Splenectomy

Front 35

Which bacteria is a normal flora of the oropharynx and causes dental caries?

Back 35

Streptococcus mutans (Viridans group Streptococci)

Front 36

Which bacteria causes subacute bacterial endocarditis at damaged valves? Mechanism?

Back 36

Streptococcus sanguinis (Viridans group Streptococci)
(sanguis = blood and the heart contains a lot of blood)
- Makes dextrans which bind to fibrin-platelet aggregates on damaged heart valves

Front 37

Characteristics of Viridans groups Streptococci?

Back 37

Streptococcus mutans & Streptococcus sanguinis
- α-Hemolytic
- Resistant to optochin

Viridans group strep live in the mouth because they are not afraid of-the-chin (op-to-chin resistant)

Front 38

What is the name of Group A Streptococci?

Back 38

Streptococcus pyogenes

Front 39

What does Streptococcus pyogenes cause?

Back 39

Pyogenic infections:
- Pharyngitis
- Cellulitis
- Impetigo

Toxigenic infections:
- Scarlet fever
- Toxic shock-like syndrome
- Necrotizing fasciitis

Immunologic infections:
- Rheumatic fever
- Acute glomerulonephritis

Front 40

What are the pyogenic infections caused by Streptococcus pyogenes?

Back 40

- Pharyngitis
- Cellulitis
- Impetigo

Front 41

What are the toxigenic infections caused by Streptococcus pyogenes?

Back 41

- Scarlet fever
- Toxic shock-like syndrome
- Necrotizing fasciitis

Front 42

What are the immunologic infections caused by Streptococcus pyogenes?

Back 42

- Rheumatic fever
- Acute glomerulonephritis

Front 43

Characteristics of Streptococcus pyogenes?

Back 43

Group A, β-hemolysis:
- Bacitracin sensitive
- M protein

Front 44

What enhances host defenses against Streptococcus pyogenes?

Back 44

Antibodies to M protein

Front 45

How can you detect a Streptococcus pyogenes infections?

Back 45

ASO titer detects recent S. pyogenes infection

Front 46

What are the diagnostic criteria for Rheumatic Fever? Cause?

Back 46

J♥︎NES criteria:
- Joints - polyarthritis
- ♥︎ - carditis
- Nodules (subcutaneous)
- Erythema marginatum
- Sydenham chorea

Caused by Streptococcus pyogenes (group A)

Front 47

Untreated pharyngitis caused by Streptococcus pyogenes can lead to what?

Back 47

- Rheumatic fever
- Glomerulonephritis

Front 48

Impetigo more commonly precedes what immunologic manifestation of S. pyogenes?

Back 48

Impetigo more commonly precedes glomerulonephritis than pharyngitis

Front 49

What are the symptoms and cause of Scarlet Fever?

Back 49

Symptoms:
- Scarlet rash w/ sandpaper-like texture
- Strawberry tongue
- Circumoral pallor

Cause:
- Streptococcus pyogenes (group A streptococci)

Front 50

Which bacteria causes pneumonia, meningitis, and sepsis mainly in babies?

Back 50

Streptococcus agalactiae (group B streptococci)
"Group B for Babies"

Front 51

Characteristics of Streptococcus agalactiae?

Back 51

Group B, β-hemolysis:
- Bacitracin resistant (B-BRAS)
- Hippurate test (+)

Front 52

Why does Streptococcus agalactiae (group B) commonly infect babies? Implications?

Back 52

- It colonizes the vagina - then it is spread to babies during a vaginal birth
- Screen pregnant women at 35-37 weeks (patients w/ + culture receive intrapartum penicillin prophylaxis

Front 53

What is the mechanism of Streptococcus agalactiae (group B)?

Back 53

- Produces CAMP factor
- Enlarges the area of hemolysis formed by S. aureus

Front 54

Which G+ bacteria is found in normal colonic flora and can cause UTIs, biliary tract infections, and subacute endocarditis (after GI/GU procedures)?

Back 54

Enterococci faecalis and faecium (group D)

Front 55

Characteristics of Enterococci?

Back 55

Group D Streptococci
- G+
- Penicillin G resistant

Front 56

What kind of infections do Enterococci cause?

Back 56

- UTI
- Biliary tract infections
- Subacute endocarditis (following GI/GU procedures)

Front 57

What kind of bacteria are classified as Group D Streptococci? Difference?

Back 57

Enterococci (E. faecalis and E. faecium)
- Can grow in 6.5% NaCl and bile (lab test)

Non-enterococcal (S. bovis)
- Can grow in bile but not 6.5% NaCl

Front 58

What determines whether a bacteria is Group A/B/C/D?

Back 58

Lancefield grouping - based on differences in the C carbohydrate on the bacterial cell wall, variably hemolysis

Front 59

What is an important cause of nosocomial infection by Enterococci?

Back 59

VRE: Vancomycin-Resistant Enterococci

Front 60

Which G+ bacteria is found in normal colonic flora and can cause bacteremia and subacute endocarditis in colon cancer patients?

Back 60

Streptococcus bovis (group D)

Front 61

Characteristics of Streptococcus bovis (group D)?

Back 61

- Colonizes the gut
- Causes bacteremia and subacute endocarditis in colon cancer patients (Bovis in the Blood = Cancer in the Colon)
- γ-hemolysis (no hemolysis)

Front 62

Which bacteria causes pseudomembranous pharyngitis (grayish-white membrane) w/ lymphadenopathy?

Back 62

Corynebacterium diphtheriae - via exotoxin encoded by β-prophage, inhibits protein synthesis via ADP-ribosylation of EF-2

Front 63

Which bacteria releases diphtheria exotoxin? Mechanism?

Back 63

Corynebacterium diphtheriae - exotoxin encoded by β-prophage, inhibits protein synthesis via ADP-ribosylation of EF-2

ABCDEFG:
- ADP-ribosylation
- β-prophage
- Corynebacterium
- Diphtheriae
- Elongation Factor 2
- Granules

Front 64

What are the symptoms of Corynebacterium diphtheriae infection?

Back 64

- Pseudomembranous pharyngitis (grayish-white membrane)
- Lymphadenopathy
- Myocarditis
- Arrhythmias

Front 65

How do you diagnose Corynebacterium diphtheriae infection?

Back 65

- G+ rods w/ metachromatic (blue and red) granules
- Elk test for diphtheria toxin
- Black colonies on cystine-tellurite agar

Front 66

How can you prevent infection with Corynebacterium diphtheriae?

Back 66

Toxoid vaccine

Front 67

Which bacteria form spores?

Back 67

Spore-forming G+ bacteria in soil:
- Bacillus anthracis
- Clostridium perfringens
- C. tetani

Other spore formers:
- B. cereus
- C. botulinum
- Coxiella burnetti

Front 68

What causes bacteria that form spores to make spores? Purpose?

Back 68

- Form spores at the end of the stationary phase when nutrients are limited
- Spores are highly resistant to heat and chemicals

Front 69

What are the characteristics of spores?

Back 69

- Highly resistant to heat and chemicals
- Have dipicolinic acid in their core
- No metabolic activity

Front 70

How do you kill spores?

Back 70

Must autoclave (as is done to surgical equipment) by steaming at 121°C for 15 minutes

Front 71

Which bacteria are G+, spore-forming, obligate anaerobic bacilli?

Back 71

Clostridia
- C. tetani
- C. botulinum
- C. perfringens
- C. difficile

Front 72

What kind of toxin is produced by Clostridium tetani?

Back 72

Tetanospasmin / Tetanus toxin (exotoxin)

Front 73

What bacteria releases Tetanus toxin? Effects?

Back 73

Clostridium tetani
- Protease that cleaves releasing proteins for NTs
- Blocks glycine and GABA release (both are inhibitory NTs) from Renshaw cells in spinal cord
- Causes spastic paralysis (tetanic), trismus (lockjaw), and risus sardonicus (spasm of facial muscles causing a grin)

Front 74

What is trismus? Cause?

Back 74

Lockjaw - caused by Tetanus toxin from Clostridium tetani

Front 75

What is Risus Sardonicus? Cause?

Back 75

Spasm of facial muscles causing a grin - caused by Tetanus toxin from Clostridium tetani

Front 76

What kind of toxin is produced by Clostridium botulinum?

Back 76

Preformed, heat-labile toxin

Front 77

What bacteria releases a preformed, heat-labile toxin? Effects?

Back 77

Clostridium botulinum
- Inhibits ACh release at neuromuscular junction, causing botulism

Front 78

How does C. botulinum infect adults? Infants?

Back 78

"BOTulinum is from bad BOTtles of food and honey)
- Adults: disease is caused by ingestion of preformed toxin
- Babies: disease is caused by ingestion of spores in honey → floppy baby syndrome

Front 79

Why shouldn't babies eat honey?

Back 79

- Honey can contain spores from C. botulinum
- Ingestion of spores causes floppy baby syndrome (toxin inhibits ACh release at neuromuscular junction causing botulism)

Front 80

What kind of toxin is produced by Clostridium perfringens?

Back 80

α-Toxin ("lecithinase" a phospholipase)

Front 81

What bacteria releases α-Toxin? Effects?

Back 81

Clostridium perfringens
- α-Toxin - a phospholipase
- Causes myonecrosis (gas gangrene) and hemolysis
- Perfringens perforates a gangrenous leg
"PERFringens PERForates a gangrenous leg"

Front 82

What kind of toxin is produced by Clostridium difficile?

Back 82

Produces 2 toxins
- Toxin A (enterotoxin)
- Toxin B (cytotoxin)

Front 83

What bacteria releases Toxin A? Effects?

Back 83

Clostridium difficile
- Enterotoxin
- Binds to brush border of gut

Front 84

What bacteria releases Toxin B? Effects?

Back 84

Clostridium difficile
- Cytotoxin
- Causes cytoskeletal disruption via actin depolymerization → pseudomembranous colitis → diarrhea

Front 85

What often precedes infection by Clostridium difficile? Symptoms?

Back 85

- Often secondary to antibiotic use, especially clindamycin or ampicillin
- Causes diarrhea

Front 86

How do you diagnose Clostridium difficile infection? Treat?

Back 86

Diagnose:
- Detection of one or both toxins in stool (Toxin A / enterotoxin or Toxin B / cytotoxin)

Treat:
- Metronidazole or oral vancomycin
- Recurring cases: fecal transplant may prevent relapse

Front 87

What is the only bacterium with a polypeptide capsule (contains D-glutamate)?

Back 87

Bacillus anthracis

Front 88

Which bacteria causes Anthrax? Characteristics?

Back 88

Bacillus anthracis
- G+, spore-forming rod
- Produces anthrax toxin
- Only bacterium with a polypeptide capsule (contains D-glutamate)

Front 89

What are the forms of infection caused by Bacillus anthracis?

Back 89

- Cutaneous anthrax
- Pulmonary anthrax

Front 90

What are the symptoms of Cutaneous Anthrax?

Back 90

- Boil like lesion → ulcer with black eschar (painless, necrotic)
- Uncommonly progresses to bacteremia and death

Front 91

What are the symptoms of Pulmonary Anthrax?

Back 91

- Inhalation of spores → flu-like symptoms
- Rapidly progresses to fever, pulmonary hemorrhage, mediastinitis, and shock

Front 92

What is the term for Pulmonary Anthrax caused by inhalation of spores from contaminated wool?

Back 92

Woolsorters' Disease

Front 93

Which bacteria causes food poisoning commonly from reheated rice?

Back 93

Bacillus cereus

Front 94

What kind of infection is caused by Bacillus cereus? Source of infection?

Back 94

- Food poisoning: spores survive cooking rice, keeping rice warm results in germination of spores and enterotoxin formation
- Emetic type usually seen w/ rice and pasta (nausea and vomiting within 1-5 hours), d/t cereulide (preformed toxin)
- Diarrheal type causes watery, non-bloody diarrhea and GI pain w/in 8-18 hours

Front 95

What is responsible for the emetic type of food poisoning due to Bacillus cereus? How soon?

Back 95

Cereulide (preformed toxin) in rice and pasta, causes symptoms within 1-5 hours

Front 96

How quickly do diarrheal type symptoms from Bacillus cereus occur?

Back 96

Within 8-18 hours

Front 97

What bacteria can be found in unpasteurized dairy products and infected deli meats?

Back 97

Listeria monocytogenes

Front 98

Characteristics of Listeria monocytogenes?

Back 98

- G+ facultative intracellular microbe
- Produces LPS (only G+ organism to do so)

Front 99

How can Listeria monocytogenes be acquired?

Back 99

- Ingestion of unpasteurized dairy products and deli meats
- Transplacental transmission
- Vaginal transmission during birth

Front 100

How does Listeria monocytogenes avoid host defenses?

Back 100

- Avoids antibody by forming "rocket tails" (via actin polymerization) that allows them to move through the cytoplasm and into the cell membrane
- Characteristic tumbling motility

Front 101

What can infection with Listeria monocytogenes cause?

Back 101

- Amnionitis, septicemia, and spontaneous abortion in pregnant women
- Granulomatosis infantiseptica
- Neonatal meningitis
- Meningitis in immunocompromised patients
- Mild gastroenteritis in healthy individuals

Front 102

What does Listeria monocytogenes cause in healthy patients? How do you treat?

Back 102

Gastroenteritis (mild) - usually self-limited

Front 103

What does Listeria monocytogenes cause in pregnant patients?

Back 103

- Amnionitis
- Septicemia
- Spontaneous abortion

Front 104

What does Listeria monocytogenes cause in infants patients? How do you treat?

Back 104

- Granulomatosis infantiseptica
- Neonatal meningitis (treat with Ampicillin)

Front 105

What does Listeria monocytogenes cause in immunocompromised patients? How do you treat?

Back 105

Meningitis (treat empirically with Ampicillin)

Front 106

Which bacteria form long, branching filaments resembling fungi?

Back 106

- Actinomyces
- Nocardia

Front 107

Which bacteria causes oral/facial abscesses that drain through sinus tracts forming yellow "sulfur" granules? How do you treat?

Back 107

Actinomyces - treat with Penicillin

Front 108

Characteristics of Actinomyces?

Back 108

- G+ anaerobe
- Forms long-branching filaments that resemble fungi
- Not acid fast
- Normal oral flora
- Causes oral/facial abscesses that drain through sinus tracts forming yellow "sulfur granules"
- Treat with Penicillin

Front 109

Which bacteria causes pulmonary infections in immunocompromised patients and cutaneous infections after trauma in immunocompromised patients? How do you treat?

Back 109

Nocardia - treat with Sulfonamides

Front 110

Characteristics of Nocardia?

Back 110

- G+ aerobe
- Forms long, branching filaments resembling fungi
- Acid fast (weak)
- Found in soil
- Causes pulmonary infections in immunocompromised patients
- Causes cutaneous infections after trauma in immunocompromised patients
- Treat with Sulfonamides

Front 111

What causes Tuberculosis? Different forms of infection?

Back 111

Infection with Mycobacterium tuberculosis
- Primary infection: non-immune host (usually a child)
- Secondary infection: partially immune hyper-sensitized host (usually adult)

Front 112

What are the signs of a Primary Tuberculosis?

Back 112

Occurs in a non-immune host (usually a child)
- Ghon Complex: Hilar nodes & Ghon focus (usually in mid zone of lung)

Front 113

What can Primary Tuberculosis lead to?

Back 113

- Heals by fibrosis → immunity and hypersensitivity → Tuberculin (+)

- Progressive lung disease (HIV, malnutrition) → death (rare)

- Severe bacteremia → miliary tuberculosis → death

- Pre-allergic lymphatic or hematogenous dissemination → dormant tubercle bacilli in several organs → REACTIVATION in adult life

Front 114

What are the signs of a Secondary Tuberculosis?

Back 114

Fibrocaseous cavitary lesion (usually in upper lobes)

Front 115

What can Secondary Tuberculosis lead to?

Back 115

Extrapulmonary Tuberculosis
- CNS: parenchymal tuberculoma or meningitis
- Vertebral body: Pott disease
- Lymphadenitis
- Renal
- GI
- Adrenals

Front 116

What does a positive PPD test mean?

Back 116

Either:
- Current infection with Mycobacterium tuberculosis
- Past exposure to Mycobacterium tuberculosis
- BCG vaccinated

Front 117

What does a negative PPD test mean?

Back 117

Either:
- No infection
- Anergic (steroids, malnutrition, immunocompromise) and in sarcoidosis

Front 118

Which test is more specific than PPD for Mycobacterium tuberculosis infection?

Back 118

Interferon-γ Release Assay (IGRA)
- More specific
- Fewer false positives from BCG vaccination

Front 119

Which vaccine is used to prevent Tuberculosis?

Back 119

BCG vaccine

Front 120

What is the appearance of a caseating granuloma in tuberculosis infection?

Back 120

- Central necrosis (pinkish region in upper left)
- Multinucleated Langhans giant cell (arrow)

Front 121

What are the symptoms of TB?

Back 121

- Fever
- Night sweats
- Weight loss
- Hemoptysis

Front 122

What are the species of Myocbacterium? What disease do they cause?

Back 122

- M. tuberculosis (TB, often resistant to multiple drugs)
- M. kansasii (pulmonary TB-like symptoms)
- M. avium-intracellulare (causes disseminated, non-TB disease in AIDS; often resistant to multiple drugs; prophylactic tx with azithromycin)
- M. leprae (Leprosy / Hansen disease)

Front 123

What are the characteristics of all Mycobacteria?

Back 123

All are acid-fast organisms

Front 124

Which bacteria causes disseminated, non-TB disease in AIDS patients? Treatment / prevention?

Back 124

Mycobacterium avium-intracellulare
- Often resistant to multiple drugs
- Prophylactic treatment with Azithromycin

Front 125

What is released by virulent strains of Mycobacteria? Implication?

Back 125

Cord fator is found in virulent strains
- Inhibits macrophage maturation
- Induces release of TNF-α

Sulfatides (surface glycolipids)
- Inhibit phagolysosomal fusion

Front 126

Which bacteria causes this appearance?

Back 126

Mycobacterium leprae (Leprosy / Hansen disease)

Front 127

Characteristics of Mycobacterium leprae?

Back 127

- Acid-fast bacillus
- Likes cool temperatures
- Cannot be grown in vitro
- Reservoir in US: armadillos

Front 128

What does Mycobacterium leprae infect?

Back 128

- Skin
- Superficial nerves: "glove and stocking" loss of sensation

- Armadillos (reservoir)

Front 129

What are the forms of Leprosy / Hansen disease? Characteristics?

Back 129

Lepromatous:
- Diffuse presentation over skin
- Leonine (lion-like) facies
- Communicable
- Characterized by low cell-mediated immunity w/ a humoral Th2 response

Tuberculoid:
- Limited to a few hypoesthetic, hairless skin plaques
- Characterized by high cell-mediated immunity with a largely Th1 type immune response

Front 130

Which form of Leprosy has a LOW cell-mediated immunity with a humoral Th2 response?

Back 130

Lepromatous form

Front 131

Which form of Leprosy has a HIGH cell-mediated immunity with a largely Th1-type immune response?

Back 131

Tuberculoid form

Front 132

How do you treat the two forms of Leprosy / Hansen disease?

Back 132

Lepromatous form:
- Dapsone, Rifampin, and Clofazimine for 2-5 years

Tuberculoid form:
- Dapsone and Rifampin for 6 months

Front 133

How should you first distinguish G- (pink) bacteria?

Back 133

Shape
- Diplococci
- "Coccoid" rods
- Rods
- Oxidase (+) comme shaped

Front 134

Which bacteria are G- diplococci? How do you distinguish them?

Back 134

Distinguish based on ability to ferment maltose
- Neisseria meningitidis (ferments maltose - meningitiids starts with "m")
- Neisseria gonorrhoeae (non-fermenter)

Front 135

Which bacteria are G- coccoid rods? How do you distinguish them?

Back 135

* Haemophilus influenzae (requires factors V and X)
* Bordetella pertussis
- Pasteurella (animal bites)
- Brucella (brucellosis)

Front 136

Which bacteria are G- rods? How do you distinguish them?

Back 136

Distinguish based on ability to ferment lactose and distinguish non-fermenters by oxidase capability:

Lactose fermenters:
- Fast: Klebsiella, E. coli, Enterobacter
- Slow: Citrobacter, Serratia, etc.

Lactose non-fermenters:
- Oxidase (+): Pseudomonas
- Oxidase (-): Shigella, Salmonella, Proteus, Yersinia

Front 137

Which bacteria are lactose fermenting G- rods? How do you distinguish them?

Back 137

Fast fermenters:
* Klebsiella
* E. coli
- Enterobacter

Slow fermenters:
- Citrobacter
- Serratia

Lactose is "KEE" - Test with Mac"C"on"KEE'S" agar

Front 138

Which bacteria are non-lactose fermenting G- rods? How do you distinguish them?

Back 138

Oxidase (+):
- Pseudomonas

Oxidase (-):
- Shigella
- Salmonella
- Proteus
- Yersinia

Front 139

Which bacteria are oxidase (+), comma shaped G-? How do you distinguish them?

Back 139

Grows in 42°C:
- Campylobacter jejuni

Grows in alkaline media:
- Vibrio cholerae

Produces urease:
- Helicobacter pylori

Front 140

How do you determine if a bacteria can ferment lactose?

Back 140

*If it can grow pink colonies on MacConkey agar

Remember macConKEE'S agar to remember which bacteria can ferment lactose -
- Citrobacter (slow)
- Klebsiella (fast)
- E. coli (fast)
- Enterobacter (fast)
- Serratia (slow)

*Can also test on EMB agar - lactose fermenters grow as purple/black colonies (E. coli grows purple colonies w/ a green sheen)

Front 141

Can E. coli ferment lactose? Why or why not?

Back 141

Yes - E. coli produces β-galactosidase, which breaks down lactose into glucose and galactose

Front 142

G- bacilli are resistant to what antibiotics? What are they susceptible to?

Back 142

- Resistant to Penicillin G and Vancomycin (G- outer membrane layer inhibits entry)

- Susceptible to Penicillin derivatives such as Ampicillin and Amoxicillin

Front 143

Neisseria species are what type of bacteria? What can they ferment?

Back 143

G- diplococci
- MeninGococci ferment both Maltose and Glucose (meningitidis)
- Gonococci ferment Glucose (gonorrhoeae)

Front 144

What do Neisseria species produce?

Back 144

IgA proteases

Front 145

Which bacteria is sexually transmitted and can also cause septic arthritis, neonatal conjunctivitis, pelvic inflammatory disease (PID), and Fitz-Hugh-Curtis Syndrome? Treatment?

Back 145

Neisseria gonorrhoeae

Treat: Ceftriaxone (+ Azithromycin or Doxycycline for possible Chlamydia co-infection)

Front 146

Characteristics of Neisseria gonorrhoeae?

Back 146

G- diplococci
- Produces IgA proteases
- Ferments glucose only
- Often intracellular (within neutrophils)
- No polysaccharide capsule
- No vaccine (d/t rapid antigenic variation of pilus proteins)

Front 147

What can Neisseria gonorrhoeae infection cause? Prevention?

Back 147

Prevent sexual transmission w/ condoms
- Gonorrhea
- Septic arthritis
- Neonatal conjunctivitis (prevent transmission w/ erythromycin ointment)
- Pelvic Inflammatory Disease (PID)
- Fitz-Hugh-Curtis Syndrome

Front 148

Which bacteria is spread via respiratory and oral secretions, causing meningococcemia and meningitis as well as Waterhouse-Friderichsen syndrome? Treatment?

Back 148

Neisseria meningitidis

Treat: Ceftriaxone or Penicillin G

Front 149

Characteristics of Neisseria meningitidis?

Back 149

G- diplococci
- Produces IgA proteases
- Ferments glucose AND maltose
- Polysaccharide capsule
- Vaccine (none for type B)
- Spread via respiratory and oral secretions

Front 150

What can Neisseria meningitidis infection cause? Prevention?

Back 150

- Meningococcemia (picture)
- Meningitis
- Waterhouse-Friderichsen syndrome

Prevent: Rifampin, Ciprofloxacin, or Ceftriaxone prophylaxis in close contacts

(Ceftriaxone or Penicillin G can be used for treatment)

Front 151

Which bacteria causes an infection that leads to the "thumbprint sign" on lateral neck radiograph?

Back 151

Haemophilus influenzae epiglottitis

Front 152

Characteristics of Haemophilus influenzae?

Back 152

Small G- coccobacillary rod
- Aerosol transmission
- Most invasive disease caused by capsular type B
- Produces IgA protease
- Culture on chocolate agar requires factors V (NAD+) and X (Hematin) for growth

Front 153

Which type of Haemophilus influenzae causes the most invasive disease? What do the other types cause?

Back 153

- Most invasive disease caused by capsular type B
- Nontypeable strains cause mucosa infections (eg, otitis media, conjunctivitis, or bronchitis)

Front 154

What kind of infection is caused by Haemophilus influenzae?

Back 154

HaEMOPhilus causes
- Epiglottitis ("cherry red" in children)
- Meningitis
- Ototis media
- Pneumonia

Front 155

How do you culture Haemophilus influenzae?

Back 155

On Chocolate agar, requires:
- Factor V (NAD+), also can be grown w/ S. aureus which provides Factor V
- Factor X (hematin)

"When a child has "flu", mom goes to five (V) and dime (X) store to buy some chocolate"

Front 156

How do you treat Haemophilus influenzae infections?

Back 156

- Mucosal infections (eg, otitis media, conjunctivitis, bronchitis) with Amoxicillin +/- Clavulanate

- Meningitis with Ceftriaxone

Front 157

How do you prevent spread / infection of Haemophilus influenzae infections?

Back 157

- Prevention in close contacts exposed to AEROSOL TRANSMISSION: Rifampin

- Prevention w/ vaccine: contains type B capsular polysacchardie (polyribosylribitol phosphate) conjugated to diphtheria toxoid or other protein (given between 2-18 months)

Front 158

Which bacteria causes severe pneumonia, fever, GI and CNS symptoms?

Back 158

Legionella pneumophila (Legionnaire's disease)

Front 159

Characteristics of Legionella pneumophila?

Back 159

G- rod
- Gram stains poorly (use SILVER stain)
- Grow on CHARCOAL yeast extract culture with IRON and CYSTEINE
- Detected clinically by presence of antigen in urine
- Aerosol transmission from environmental water source habitat (eg, AC systems, hot water tanks); no person-to-person transmission

"Think of a French LEGIONNAIRE (soldier) with his SILVER helmet, sitting around a campfire (CHARCOAL) with his IRON dagger - his is no SISSY (CYSTEINE)"

Front 160

How do you diagnose Legionella pneumophila? Other signs?

Back 160

* Presence of antigen in urine is used clinically
- Labs show hyponatremia
- G- rod, better stained w/ Silver Stain
- Cultured on Charcoal yeast extract with Iron and Cysteine

Front 161

How does Legionella pneumophila get spread?

Back 161

- Aerosol transmission from environmental water source habitat (eg, A/C systems, hot water tanks)
- Not person-to-person

Front 162

What disease states can Legionella pneumophila infection cause? Treatment?

Back 162

- Legionnaires' Disease: severe pneumonia, fever, GI and CNS symptoms
- Pontiac Fever: mild flu-like syndrome

- Treat: Macrolide or Quinolone

Front 163

Which bacteria is associated with wound and burn infections?

Back 163

Pseudomonas aeruginosa

Front 164

Characteristics of Pseudomonas aeruginosa?

Back 164

G- Rod:
- Aerobic (AERuginosa
- Non-lactose fermenting
- Oxidase (+)
- Produces pyocyanin (blue-green pigment)
- Grape-like odor
- Water source
- Produces endotoxin (fever, shock) and exotoxin A (inactivates EF-2)

Front 165

What toxins does Pseudomonas aeruginosa produce? Effects?

Back 165

- Endotoxin → fever and shock
- Exotoxin A → inactivates EF-2

Front 166

What color is Pseudomonas aeruginosa? How?

Back 166

Blue/green pigment called Pyocyanin

Front 167

What kind of infections does Pseudomonas aeruginosa cause?

Back 167

PSEUDOmonas associated with wound and burn infections:
- Pneumonia (especially in cystic fibrosis)
- Sepsis
- External otitis (swimmer's ear)
- UTI
- Drug use
- Diabetic Osteomyelitis (and malignant otitis externa in diabetics)

- And hot tub folliculitis

Front 168

Which bacteria causes hot tub folliculitis?

Back 168

Pseudomonas aeruginosa

Front 169

How does Pseudomonas aeruginosa affect immunocompromised patients?

Back 169

Ecthyma gangrenosum
- Rapidly progressive
- Large ulcer (arrows)
- Necrotic cutaneous lesions (arrowheads)

Front 170

What bacteria is associated with chronic pneumonia in cystic fibrosis patients?

Back 170

Pseudomonas aeruginosa (associated with biofilms)

Front 171

What are the virulence factors of E. coli?

Back 171

- Fimbriae
- K capsule
- LPS endotoxin

Front 172

What kind of infections are enhanced by the E. coli virulence factor "fimbriae"?

Back 172

- Cystitis
- Pyelonephritis

Front 173

What kind of infections are enhanced by the E. coli virulence factor "K capsule"?

Back 173

- Pneumonia
- Neonatal meningitis

Front 174

What kind of infections are enhanced by the E. coli virulence factor "LPS endotoxin"?

Back 174

Septic shock

Front 175

What are the strains of E. coli?

Back 175

- EIEC
- ETEC
- EPEC
- EHEC

Front 176

Which bacteria causes invasive dysentery (severe diarrhea with the presence of blood and mucus in the feces)? Mechanism?

Back 176

EIEC (Invasive)
- Microbe invades intestinal mucosa and causes necrosis and inflammation
- Clinical manifestation is similar to Shigella

Front 177

Which bacteria causes Travelers' Diarrhea (watery)? Mechanism?

Back 177

ETEC (Travelers')
- Produces heat-labile and heat-stable enteroToxins
- No inflammation or invasion

Front 178

Which bacteria causes diarrhea usually in children? Mechanism?

Back 178

EPEC (Pediatrics)
- No toxin produced
- Adheres to apical surface
- Flattens villi
- Prevents absorption

Front 179

Which bacteria causes non-invasive dysentery (severe diarrhea with the presence of blood and mucus in the feces)? Mechanism?

Back 179

EHEC (O157:H7 is the most common serotype)
- Produces Shiga-like toxin → Hemolytic-Uremic Syndrome
- AKA STEC (Shiga Toxin-producing E. Coli)
- Microthrombi form on endothelium damaged by toxin → mechanical hemolysis (forms schistocytes) and ↓ renal blood flow
- Microthrombi consume platelets → thrombocytopenia

Front 180

What are the components of Hemolytic Uremic Syndrome? Cause?

Back 180

- Anemia
- Thrombocytopenia
- Acute renal failure

- Caused by EHEC

- Microthrombi form on endothelium damaged by toxin → mechanical hemolysis (forms schistocytes) and ↓ renal blood flow
- Microthrombi consume platelets → thrombocytopenia

Front 181

What is the difference between EIEC and EHEC?

Back 181

- EIEC: invasive, the microbe invades intestinal mucosa, causing necrosis and inflammation leading to dysentery

- EHEC: not-invasive, toxin alone causes necrosis and inflammation leading to dysentery

Front 182

Besides the presentation and mechanism, how does EHEC differ from other forms of E. coli?

Back 182

Does not ferment sorbitol

Front 183

Which form of E. coli does not ferment sorbitol?

Back 183

EHEC

Front 184

Which bacteria is associated with the 4 A's (Aspiration pneumonia, Abscess in lungs and liver, Alcoholics, and di-A-betics)?

Back 184

Klebsiella

Front 185

Characteristics of Klebsiella?

Back 185

G- Rod
- Fast lactose fermenter
- Part of intestinal flora

Front 186

What does Klebsiella cause? Who is affected?

Back 186

*Causes lobar pneumonia (via Aspiration)
- Forms Abscesses in lungs and liver
- Common in Alcoholics and di-A-betics
- Forms mucoid colonies d/t abundant polysaccharide capsules
- Red "currant jelly" sputum
(remember 4 A's)

*Also cause of nosocomial UTIs

Front 187

Which bacteria causes patients to have a lobar pneumonia that leads to red "currant jelly" sputum?

Back 187

Klebsiella

Front 188

What are the similarities of Salmonella and Shigella?

Back 188

G- rods
- Invades intestinal mucosa and cause bloody diarrhea
- Do not ferment lactose
- Oxidase (-)

Front 189

How do Salmonella and Shigella differ in movement?

Back 189

Salmonella:
- Flagella (salmon swim)

Shigella:
- No flagella

Front 190

How do Salmonella and Shigella differ in dissemination?

Back 190

Salmonella
- Hematogenously (salmon swimming)

Shigella
- Cell-to-cell transmission
- No hematogenous spread

Front 191

How do Salmonella and Shigella differ in reservoirs?

Back 191

Salmonella
- Many animal reservoirs (salmon is an animal)

Shigella
- Only in humans and primates

Front 192

How do Salmonella and Shigella differ in production of hydrogen sulfide?

Back 192

Salmonella
- Produces hydrogen sulfide

Shigella
- Does not produce hydrogen sulfide

Front 193

How do Salmonella and Shigella differ in their response to antibiotics?

Back 193

Salmonella
- Antibiotics may PROLONG fecal excretion of organism

Shigella
- Antibiotics SHORTEN duration of fecal excretion of organism

Front 194

How do Salmonella and Shigella differ in their immune system response?

Back 194

Salmonella
- Invades intestinal mucosa and causes a MONOCYTIC response

Shigella
- Invades intestinal mucosa and causes a PMN infiltration

Front 195

Which disease is characterized by rose spots on the abdomen, fever, headache, and diarrhea and can remain in the gallbladder causing a carrier state? Cause?

Back 195

Typhoid Fever (caused by Salmonella typhi) - only found in humans

Front 196

What are the symptoms of Typhoid Fever (Salmonella typhi)?

Back 196

- Rose spots on abdomen
- Fever
- Headache
- Diarrhea
- Can remain in gallbladder and cause a carrier state

Front 197

Characteristics of Salmonella?

Back 197

- Flagella (salmon swim)
- Can disseminate hematogenously
- Have many animal reservoirs
- Produce hydrogen sulfide
- Antibiotics may PROLONG fecal excretion of organism
- Invades intestinal mucosa and causes a monocytic response
- Can cause bloody diarrhea
- Does not ferment lactose

Front 198

Characteristics of Shigella?

Back 198

- No flagella
- Cell to cell transmission, no hematogenous spread
- Only reservoirs are humans and primates
- Does not produce hydrogen sulfide
- Antibiotics shorten duration of fecal excretion of organism
- Invades intestinal mucosa and causes a PMN infiltration
- Often causes bloody diarrhea
- Does not ferment lactose

Front 199

What bacteria is a major cause of bloody diarrhea (especially in children), and is spread through foods such as poultry, meat, and unpasteurized milk?

Back 199

Campylobacter jejuni

Front 200

Characteristics of Campylobacter jejuni?

Back 200

G- Comma or S-shaped
- Oxidase (+)
- Grows at 42°C ("Campylobacter likes the hot campfire")

Front 201

How is Campylobacter jejuni acquired?

Back 201

Fecal-oral transmission through foods such as:
- Poultry
- Meat
- Unpasteurized milk

Front 202

What does Campylobacter jejuni cause?

Back 202

- Major cause of bloody diarrhea (especially in children)
- Common antecedent to Guillain-Barré syndrome and reactive arthritis

Front 203

Which bacteria produces profuse "rice-water diarrhea"? Mechanism? Treatment?

Back 203

Vibrio cholerae
- Enterotoxin permanently activates Gs → ↑cAMP → rice-water diarrhea
- Treat with prompt oral rehydration

Front 204

Characteristics of Vibrio cholerae?

Back 204

G- comma shaped
- Oxidase (+)
- Grows in alkaline media

Front 205

Where is Vibrio cholerae more common? Treatment?

Back 205

- Endemic to developing countries
- Prompt oral rehydration is necessary

Front 206

Which bacteria causes mesenteric adenitis that can mimic Crohn disease or appendicitis? Transmission?

Back 206

Yersinia enterocolitica
- Transmitted from pet feces (eg, puppies), contaminated milk, or pork

Front 207

What disease does Yersinia enterocolitica cause? Transmission?

Back 207

- Mesenteric adenitis that can mimic Crohn disease or appendicitis
- Transmitted from pet feces (eg, puppies), contaminated milk, or pork

Front 208

Which bacteria causes gastritis and peptic ulcers (especially duodenal)?

Back 208

Helicobacter pylori

Front 209

Characteristics of Helicobacter pylori?

Back 209

G- comma shaped rods
- Oxidase (+)
- Catalase (+)
- Urease (+) - can use urea breath test or fecal antigen test
- Creates alkaline environment

Front 210

What does Helicobacter pylori cause?

Back 210

- Causes Gastritis and Peptic Ulcers (especially duodenal)
- Risk factor for gastric adenocarcinoma
- Risk factor for lymphoma

Front 211

How do you treat Helicobacter pylori infection?

Back 211

Triple therapy:
- Proton Pump Inhibitor (PPI)
- Clarithromycin
- Amoxicillin or Metronidazole

Front 212

What is the name for spiral-shaped bacteria? Types? Visualization?

Back 212

Spirochetes: BLT -
- Borrelia (big size - only spirochete that can be visualized using aniline dyes (Wright or Giemsa stain) with light microscopy)
- Leptospira
- Treponema (visualized with dark-field microscopy)

Front 213

Which type of bacteria can be visualized with dark-field microscopy?

Back 213

Treponema (type of spirochete)

Front 214

Which type of bacteria is found in water contaminated with animal urine?

Back 214

Leptospira interrogans

Front 215

What diseases are caused by Leptospira interrogans infection?

Back 215

Leptospirosis
- Flu-like symptoms
- Jaundice
- Photophobia
- Conjunctival suffusion (erythema without exudate)

Weil Disease (icterohemorrhagic leptospirosis)
- Severe form with jaundice and azotemia from liver and kidney dysfunction
- Fever
- Hemorrhage
- Anemia

Front 216

What is the cause and symptoms of Leptospirosis?

Back 216

Leptospira interrogans
- Flu-like symptoms
- Jaundice
- Photophobia
- Conjunctival suffusion (erythema without exudate)

Front 217

What is the cause and symptoms of Weil Disease?

Back 217

Caused by Leptospira interrogans
AKA icterohemorrhagic leptospirosis
- Severe form of leptospirosis with jaundice and azotemia from liver and kidney dysfunction
- Fever
- Hemorrhage
- Anemia

Front 218

Who is more likely to get infected with Leptospira interrogans (which causes leptospirosis and Weil disease)?

Back 218

Prevalent among surfers and in tropics (eg, Hawaii)

Front 219

What causes Lyme Disease?

Back 219

* Borrelia burgdorferi, which is transmitted by the tick Ixodes (also vector for Babesia)
- Natural reservoir is the mouse (important for tick life cycle)

Front 220

Where is Lyme disease more common?

Back 220

NE United States

Front 221

What are the initial symptoms of Lyme Disease (Borrela burgdorferi)?

Back 221

- Erythema chronicum migrans - expanding bulls eye red rash (picture)
- Flu-like symptoms
- +/- Nerve palsy

Front 222

What are the later symptoms of Lyme Disease (Borrela burgdorferi)?

Back 222

- Monoarthritis (large joints)
- Migratory polyarthritis
- Cardiac - AV nodal block
- Neurologic - encephalopathy, facial nerve palsy, polyneuropathy

Front 223

What mnemonic can you use to remember the symptoms of Lyme Disease?

Back 223

FAKE a Key LYME pie:
- Facial nerve palsy (typically bilateral)
- Arthritis
- Kardiac block
- Erythema migrans

Front 224

How do you treat Lyme Disease (Borrelia burgdorferi)?

Back 224

Doxycycline and Ceftriaxone

Front 225

What bacteria causes Syphilis?

Back 225

Treponema pallidum (spirochete)

Front 226

What are the stages of Syphilis?

Back 226

- 1° Syphilis
- 2° Syphilis
- 3° Syphilis
- Congenital Syphilis

Front 227

What are the signs of 1° Syphilis?

Back 227

Localized disease, presents with PAINLESS chancre

Front 228

What are the microscopic and lab findings of 1° Syphilis?

Back 228

- Dark-field microscopy can visualize treponemes in fluid from chancre
- Serologic testing: VDRL/RPR (non-specific), confirm diagnosis with specific test (eg, FTA-ABS)

Front 229

What are the signs of 2° Syphilis?

Back 229

- Disseminated disease / Systemic
- Constitutional symptoms
- Maculopapular rash (palms and soles)
- Condylomata lata (wart like lesions on the genitals)

Front 230

What are the microscopic and lab findings of 2° Syphilis?

Back 230

- Dark-field microscopy can visualize treponemes
- Serologic testing: VDRL/RPR (non-specific), confirm diagnosis with specific test (eg, FTA-ABS)

Front 231

Following the systemic (2° stage) of syphilis, what happens?

Back 231

Latent syphilis stage
- Positive serology without symptoms

Front 232

What are the signs of 3° Syphilis?

Back 232

- Gummas (chronic granulomas)
- Aortitis (vasa vasorum destruction)
- Neurosyphilis (tabes dorsalis, "general paresis")
- Argyll Robertson pupil (constricts w/ accommodation but not reactive to light)

- Broad-based ataxia
- (+) Romberg's test
- Charcot joint (progressive degeneration of a weight bearing joint, marked by bony destruction, bone resorption, and eventual deformity)
- Stroke without hypertension

Front 233

What are the lab findings of 3° Syphilis?

Back 233

For neurosyphilis: test spinal fluid with VDRL or RPR

Front 234

What are the signs of congenital syphilis?

Back 234

- Saber shins
- Saddle nose
- CN VIII deafness
- Hutchinson teeth
- Mulberry molars

(spreads typically after first trimester)

Front 235

How do you prevent syphilis and congenital syphilis?

Back 235

*Treat with Penicillin G

- Prevent congenital syphilis: treat mother early in pregnancy, as placental transmission typically occurs after 1st trimester

Front 236

What is the "Prostitute Pupil"? AKA? Sign of?

Back 236

Argyll Robertson Pupil
- Pupil constricts with accommodation but is not reactive to light
- Associated with 3° syphilis

Front 237

What is the VDRL test used for? Utility?

Back 237

Detects non-specific antibody that reacts with beef cardiolipin; widely used for syphilis (quantitative, sensitive, but not specific)

False positives can be caused by:
- Viruses (mono, hepatitis)
- Drugs
- Rheumatic fever
- Lupus and leprosy

Front 238

What is the term for flu-like syndrome that begins after antibiotics are started? Why?

Back 238

Jarish-Herxheimer Reaction
- Due to killed bacteria releasing pyrogens (produces fever)

Front 239

What is the Jarish-Herxheimer Reaction?

Back 239

- Causes flu-like syndrome that begins after antibiotics are started
- Due to killed bacteria releasing pyrogens (produces fever)

Front 240

What is the term for infectious disease transmitted between animals and humans?

Back 240

Zoonosis

Front 241

Which zoonotic species is transmitted by Ixodes ticks? Source? Disease?

Back 241

Anaplasma species
- Live on deer and mice
- Causes anaplasmosis

Borrelia burgdorferi
- Lives on deer and mice
- Causes Lyme disease

Front 242

Which zoonotic species is transmitted by a cat scratch? Disease?

Back 242

Bartonella species
- Cat scratch disease, bacillary angiomatosis

Front 243

Which zoonotic species is transmitted by louse? Disease?

Back 243

Borrelia recurrentis
- Relapsing fever
- Recurrent due to variable surface antigens

Rickettsia prowazekii
- Epidemic typhus

Front 244

Which zoonotic species is transmitted by unpasteurized dairy? Disease?

Back 244

Brucella specia
- Brucellosis / undulant fever

Front 245

Which zoonotic species is transmitted by puppies and livestock? Source? Disease?

Back 245

Campylobacter
- Fecal-oral transmission via ingestion of undercooked meat
- Bloody diarrhea

Front 246

Which zoonotic species is transmitted by parrots and other birds? Disease?

Back 246

Chlamydophila psittaci
- Psittacosis

Front 247

Which zoonotic species is transmitted by aerosols of cattle / sheep amniotic fluid? Disease?

Back 247

Coxiella burnetii
- Q fever

Front 248

Which zoonotic species is transmitted by lone star ticks? Disease?

Back 248

Ehrlichia chaffeensis
- Ehrlichiosis

Front 249

Which zoonotic species is transmitted by rabbits? Disease?

Back 249

Francisella tularensis (also via ticks and deer fly)
- Tularemia

Front 250

Which zoonotic species is transmitted by animal urine? Disease?

Back 250

Leptospira species
- Leptospirosis

Front 251

Which zoonotic species is transmitted by armadillos? Disease?

Back 251

Mycobacterium leprae
- Leprosy
- Also spread by humans with lepromatous leprosy

Front 252

Which zoonotic species is transmitted by animal bites (cats, dogs)? Disease?

Back 252

Pasteurella multocida
- Cellulitis and osteomyelitis

Front 253

Which zoonotic species is transmitted by Dermacentor ticks? Disease?

Back 253

Rickettsia rickettsii
- Rocky Mountain spotted fever

Front 254

Which zoonotic species is transmitted by fleas? Disease?

Back 254

Rickettsia typhi
- Endemic typhus

Yersinia pestis
- Plaque
- Rats and prairie dogs are reservoirs

Front 255

Which zoonotic species has a reservoir in rats and prairie dogs? Disease?

Back 255

Yersinia pestis
- Causes the plague
- Transmitted by fleas

Front 256

Which bacteria presents as a gray vaginal discharge with a fishy smell?

Back 256

Gardnerella vaginalis

Front 257

Characteristics of Gardnerella vaginalis?

Back 257

- Pleomorphic
- Gram-variable rod
- Involved in vaginosis
- CLUE cells or vaginal epithelial cells covered with Gardnerella bacteria are visible under the microscope (arrow)

Front 258

What causes Gardnerella vaginalis?

Back 258

* Not sexually transmitted
- Associated with sexual activity
- Overgrowth of certain anaerobic bacteria in vagina

Front 259

How is Gardnerella vaginalis treated?

Back 259

Metronidazole or (to treat anaerobic bacteria) Clindamycin

Front 260

What are the vector-born illnesses? Vector?

Back 260

- Rocky Mountain Spotted Fever - tick is vector and carries Rickettsia rickettsii
- Typhus - endemic vector is fleas (R. typhi) and epidemic vector is human body louse (R. prowazekii)
- Ehrlichiosis - tick is vector and carries Ehrlichia
- Anaplasmosis - vector is tick and carries Anaplasma
- Q fever - no arthropod vector, Coxiella burnetii spread via tick feces and cattle placenta

Front 261

How do you treat all Rickettsial diseases and vector-borne illnesses?

Back 261

Doxycycline

Front 262

In which Rickettsial diseases and vector-borne illnesses is a rash common?

Back 262

Rash common:
- Rocky Mountain spotted fever (Rickettsia rickettsii - tick)
- Typhus (R. typhi - fleas (endemic); R. prowazekii - human body louse (epidemic))

Front 263

In which Rickettsial diseases and vector-borne illnesses is a rash rare?

Back 263

Rash rare:
- Ehrlichiosis (Ehrlichia - tick)
- Anaplasmosis (Anaplasma - tick)
- Q fever (Coxiella burneii - tick feces and cattle placenta)

Front 264

Which bacteria causes a rash that typically starts at wrists and ankles and then spreads to trunk, palms, and soles? Where is it more common?

Back 264

Rickettsia rickettsii (Rocky Mountain Spotted Fever)
- Primarily in S. Atlantic states, especially N. Carolina

Front 265

Characteristics of Rickettsia rickettsii?

Back 265

Obligate intracellular organisms
- Requires CoA and NAD+ because they can't synthesize ATP

Front 266

What is the classic presentation of Rocky Mountain Spotted Fever?

Back 266

Triad: headache, fever, rash (vasculitis)

Front 267

In which infections is there a "palms and soles" rash?

Back 267

CARS = you drive CARS using your palms and soles
- Coxsackievirus A infection (hand foot and mouth disease)
- Rocky mountain spotted fever
- 2° Syphilis (systemic)

Front 268

What are the different causes of Typhus? How do they differ?

Back 268

Rickettsia typhi
- Endemic
- Spread by fleas

Rickettsii prowazekii
- Epidemic
- Human body louse

Front 269

What are the symptoms of Typhus?

Back 269

Rash starts centrally (trunk) and spreads out, SPARING the palms and soles

Front 270

What are the characteristics of Ehrlichiosis?

Back 270

- Caused by Ehrlichia - vector is tick
- Monocytes with morulae (berry like inclusions) in cytoplasm (picture)
- Rarely presents with a rash

Front 271

Which disease is pictured: monocytes with morulae (berry-like inclusions) in cytoplasm?

Back 271

Ehrlichiosis - caused by Ehrlichia (vector is a tick)

Front 272

What are the characteristics of Anaplasmosis?

Back 272

- Caused by Anaplasma, vector is tick
- Granulocytes with morulae in cytoplasm
- Rarely presents with rash

Front 273

Which disease is characterized by granulocytes with morulae in cytoplasm?

Back 273

Anaplasmosis - caused by Anaplasma (vector is tick)

Front 274

What are the characteristics of Q fever?

Back 274

- Caused by Coxiella burnetti (can survive outside in its endospore form)
- No arthopod vector
- Tick feces and cattle placenta release spores that are inhaled as aerosols
- Presents as pneumonia
- Rarely presents with rash

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Which bacteria has Elementary bodies and Reticulate bodies?

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Chlamydiae

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What are the requirements of Chlamydiae?

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Obligate intracellular organisms - cannot make their own ATP
- Cytoplasmic inclusions seen on Giemsa or fluorescent antibody-stained smear
- Chlamydial cell wall is unusual in that it lacks muramic acid

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What kind of infections does Chlamydiae cause?

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Mucosal infections
- C. trachomatis causes reactive arthritis (Reiter syndrome), follicular conjunctivitis (picture), non-gonococcal urethritis, and PID
- C. pneumoniae and C. psittaci cause atypical pneumonia (aerosol transmission)

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What are the two forms of Chlamydiae?

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- Elementary Body (small dense) is "Enfectious" and "Enters" cells via "Endocytosis" where it transforms into a Reticulate Body
- Reticulate Body "Replicates" in cell by fission; "Reorganizes" into Elementary Bodies

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Which bacteria causes reactive arthritis (Reiter syndrome), follicular conjunctivitis (picture), non-gonococcal urethritis, and PID?

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Chlamydiae trachomatis

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Which bacteria causes atypical pneumonia and is transmitted by an aerosol?

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Chlamydiae pneumoniae and Chlamydiae psittaci (notable for an avian reservoir)

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How do you treat Chlamydiae infections?

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Azithromycin (favored because one time treatment) or Doxycycline

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How do you diagnose Chlamydiae infection?

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Lab: cytoplasmic inclusions seen on Giemsa stain or fluorescent antibody-stained smear

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What are the Chlamydiae trachomatis serotypes?

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- Types A, B, and C
- Types D-K
- Types L1, L2, and L3

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Which serotypes of Chlamydiae trachomatis cause chronic infection and can cause blindness due to follicular conjunctivitis? Other characteristics?

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Types A, B, and C
- Africa
- Blindness
- Chronic Infection

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Which serotypes of Chlamydiae trachomatis cause urethritis / PID, ectopic pregnancy, neonatal pneumonia (staccato cough), and neonatal conjunctivitis?

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Types D-K (everything else)
- Neonatal disease can be acquired during passage through infected birth canal

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Which serotypes of Chlamydiae trachomatis cause Lymphogranuloma Venereum? Symptoms?

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Types L1, L2, and L3
- Small, painless ulcers on genitals
- Swollen, painful inguinal lymph nodes that ulcerate (buboes)
- Treat with doxycycline

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Which bacteria is the classic cause of atypical "walking pneumonia"?

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Mycoplasma pneumoniae (more common in patients < 30 years old; common outbreaks in military recruits and prisons)

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What are the symptoms of "walking pneumonia"? When is this more common? Cause?

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- Insidious onset
- Headache
- Non-productive cough
- Patchy or diffuse interstitial infiltrate
- X-ray looks worse than patient
- More common in patients < 30 years old
- Frequent outbreaks in military recruits and prisons

- Cause: Mycoplasma pneumoniae

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What are the lab results for a patient with "walking pneumonia" caused by Mycoplasma pneumoniae?

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- X-ray looks worse than patient (patchy or diffuse interstitial infiltrate)
High titer of cold agglutinins (IgM), which can agglutinate or lyse RBCs - (remember it is cold in Moscow)
- Grows on Eaton agar

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How do you treat "walking pneumonia" caused by Mycoplasma pneumoniae?

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Macrolide, Doxycycline, or Fluoroquinolone

(penicillin ineffective since Mycoplasma have no cell wall)

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Why will penicillin be ineffective in a case of walking pneumonia?

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Typical cause is Mycoplasma pneumoniae (which has no cell wall so penicillin will be ineffective)

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Characteristics of Mycoplasma pneumoniae?

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- No cell wall
- Not seen on Gram stain
- Bacterial membrane contains sterols for stability