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292 Cards in this Set

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  • Back

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

- Actinomyces (anaerobe, not acids fast)
- Nocardia (aerobe, acid fast)
- Actinomyces (anaerobe, not acids fast)
- Nocardia (aerobe, acid fast)
Which bacteria are G+ rods? How do you distinguish some of them?
- Clostridium (anaerobe)
- Corynebacterium
- Listeria
- Bacillus (aerobe)
- Mycobacterium (acid-fast)
- Clostridium (anaerobe)
- Corynebacterium
- Listeria
- Bacillus (aerobe)
- Mycobacterium (acid-fast)
How do you distinguish the G+ cocci?
- Catalase test
- Coagulase test
- Hemolysis
- Catalase test
- Coagulase test
- Hemolysis
Which bacteria are G+ and catalase +? How do you distinguish them?
Staphylococcus (clusters)
- Coagulase +: S. aureus
- Coagulase -: Novobiocin sensitive S. epidermidis and Novobicin resistant S. saprophyticus
Staphylococcus (clusters)
- Coagulase +: S. aureus
- Coagulase -: Novobiocin sensitive S. epidermidis and Novobicin resistant S. saprophyticus
Which bacteria are G+ and catalase -? How do you distinguish them?
Streptococcus (chains)
- Distinguish based on hemolysis
Streptococcus (chains)
- Distinguish based on hemolysis
Which bacteria are G+, catalase +, and coagulase +? Organization?
S. aureus - cocci in clusters
Which bacteria are G+, catalase +, and coagulase -? Organization?
Clusters of cocci:
- Novobiocin sensitive S. epidermidis
- Novobiocin resistant S. saprophyticus

"NO StRESs": NOvobiocin - Saprophyticus is Resistant and Epidermidis is Sensitive
Clusters of cocci:
- Novobiocin sensitive S. epidermidis
- Novobiocin resistant S. saprophyticus

"NO StRESs": NOvobiocin - Saprophyticus is Resistant and Epidermidis is Sensitive
Which bacteria are G+, catalase -, and have partial hemolysis (green)?
α-hemolytic Streptococcus (chains)
- S. pneumoniae
- Viridans streptococci
α-hemolytic Streptococcus (chains)
- S. pneumoniae
- Viridans streptococci
Which bacteria are G+, catalase -, and have complete hemolysis (clear)?
β-hemolytic Streptococcus (chains)
- Group A: S. pyogenes
- Group B: S. agalactiae
β-hemolytic Streptococcus (chains)
- Group A: S. pyogenes
- Group B: S. agalactiae
Which bacteria are G+, catalase -, and have no hemolysis?
γ-hemolytic Streptococcus (chains)
- Group D: Enterococcus - E. faecalis
- Non-enterococcus: S. bovis
γ-hemolytic Streptococcus (chains)
- Group D: Enterococcus - E. faecalis
- Non-enterococcus: S. bovis
What are the types of hemolysis?
- 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
- 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
What does α-hemolysis mean? What are the types of bacteria that fall under this category?
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 resist...
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
What does β-hemolysis mean? What are the types of bacteria that fall under this category?
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: Baci...
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
What does γ-hemolysis mean? What are the types of bacteria that fall under this category?
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
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
What does the "on the office's "staph" retreat, there was no stress" mnemonic mean?
Staphylococcus - NO StRESs:
Novobiocin -
- Saprophyticus is Resistant
- Epidermidis is Senstive
What does the "overpass" mnemonic indicate?
OVRPS:

Optochin
- Viridans is Resistant
- Pneumoniae is Sensitive
What does the "B-BRAS" mnemonic indicate?
B-BRAS

Bacitracin
- Group B strep are Resistant
- Group A strep are Sensitive
Which bacteria:
- G+ cocci in clusters
- Protein A (virulence factor)
Which bacteria:
- G+ cocci in clusters
- Protein A (virulence factor)
Staphylococcus aureus
Staphylococcus aureus
Which virulence factor does Staphylococcus aureus use? Mechanism?
Protein A:
- Binds Fc-IgG
- Inhibits complement activation and phagocytosis
Where does Staphylococcus aureus colonize / infect?
- Commonly colonizes: nose

Inflammatory Disease:
- Skin infections
- Organ abscesses
- Pneumonia (often after influenza virus infection)
- Endocarditis
- Osteomyelitis
What does Staphylococcus aureus cause?
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
What are the toxin mediated diseases of S. aureus? Toxin?
- Toxic Shock Syndrome (TSST-1)
- Scalded Skin Syndrome (Exfoliative Toxin)
- Rapid-onset food poisoning (enterotoxins)
What is an important cause of serious nosocomial and community-acquired infections?
MRSA (Methicillin-Resistant S. aureus)
- Resistant to methicillin and nafcillin because of altered penicillin binding protein
What is TSST? Mechanism of action? What does it cause?
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
What predisposes to Toxic Shock Syndrome?
Use of vaginal or nasal tampons
Which bacteria causes rapid food poisoning? Mechanism?
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
How does S. aureus form an abscess?
Forms fibrin clot around itself → abscess
Which bacteria is known for infection prosthetic devices and IV catheters? Mechanism?
Staphylococcus epidermidis
- Produces adherent biofilms to these medical devices
Characteristics of Staphylococcus epidermidis?
Catalase (+), Coagulase (-)
- Infects prosthetic devices and IV catheters by producing adherent biofilms
- Component of normal skin flora
- Contaminates blood cultures
- Novobiocin sensitive (No StRESs)
Catalase (+), Coagulase (-)
- Infects prosthetic devices and IV catheters by producing adherent biofilms
- Component of normal skin flora
- Contaminates blood cultures
- Novobiocin sensitive (No StRESs)
Which bacteria are the first and second most common cause of uncomplicated UTI in young women?
1. E. coli
2. Staphylococcus saprophyticus
Characteristics of Staphylococcus saprophyticus?
Catalase (+), Coagulase (-)
- 2nd most common cause of uncomplicated UTI in young women
- Novobiocin resistant (No StRES)
Catalase (+), Coagulase (-)
- 2nd most common cause of uncomplicated UTI in young women
- Novobiocin resistant (No StRES)
What does Streptococcus pneumoniae cause?
Most common cause of:
- Meningitis
- Otitis media (in children)
- Pneumonia
- Sinusitis

MOPS
(MOPS also stands for Most are Optochin Sensitive)
Characteristics of Streptococcus pneumoniae?
Catalase (-), α-hemolysis (partial)
- Lancet-shaped
- G+ diplococci
- Encapsulated (no virulence w/o capsule)
- IgA protease
- Optochin sensitive = OVRPS)
Catalase (-), α-hemolysis (partial)
- Lancet-shaped
- G+ diplococci
- Encapsulated (no virulence w/o capsule)
- IgA protease
- Optochin sensitive = OVRPS)
What are the signs of Streptococcus pneumoniae?
- Rusty sputum
- Sepsis in sickle cell anemia
- Splenectomy
Which bacteria is a normal flora of the oropharynx and causes dental caries?
Streptococcus mutans (Viridans group Streptococci)
Which bacteria causes subacute bacterial endocarditis at damaged valves? Mechanism?
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
Characteristics of Viridans groups Streptococci?
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)
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)
What is the name of Group A Streptococci?
Streptococcus pyogenes
What does Streptococcus pyogenes cause?
Pyogenic infections:
- Pharyngitis
- Cellulitis
- Impetigo

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

Immunologic infections:
- Rheumatic fever
- Acute glomerulonephritis
What are the pyogenic infections caused by Streptococcus pyogenes?
- Pharyngitis
- Cellulitis
- Impetigo
What are the toxigenic infections caused by Streptococcus pyogenes?
- Scarlet fever
- Toxic shock-like syndrome
- Necrotizing fasciitis
What are the immunologic infections caused by Streptococcus pyogenes?
- Rheumatic fever
- Acute glomerulonephritis
Characteristics of Streptococcus pyogenes?
Group A, β-hemolysis:
- Bacitracin sensitive
- M protein
Group A, β-hemolysis:
- Bacitracin sensitive
- M protein
What enhances host defenses against Streptococcus pyogenes?
Antibodies to M protein
How can you detect a Streptococcus pyogenes infections?
ASO titer detects recent S. pyogenes infection
What are the diagnostic criteria for Rheumatic Fever? Cause?
J♥︎NES criteria:
- Joints - polyarthritis
- ♥︎ - carditis
- Nodules (subcutaneous)
- Erythema marginatum
- Sydenham chorea

Caused by Streptococcus pyogenes (group A)
Untreated pharyngitis caused by Streptococcus pyogenes can lead to what?
- Rheumatic fever
- Glomerulonephritis
Impetigo more commonly precedes what immunologic manifestation of S. pyogenes?
Impetigo more commonly precedes glomerulonephritis than pharyngitis
What are the symptoms and cause of Scarlet Fever?
Symptoms:
- Scarlet rash w/ sandpaper-like texture
- Strawberry tongue
- Circumoral pallor

Cause:
- Streptococcus pyogenes (group A streptococci)
Which bacteria causes pneumonia, meningitis, and sepsis mainly in babies?
Streptococcus agalactiae (group B streptococci)
"Group B for Babies"
Characteristics of Streptococcus agalactiae?
Group B, β-hemolysis:
- Bacitracin resistant (B-BRAS)
- Hippurate test (+)
Group B, β-hemolysis:
- Bacitracin resistant (B-BRAS)
- Hippurate test (+)
Why does Streptococcus agalactiae (group B) commonly infect babies? Implications?
- 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
What is the mechanism of Streptococcus agalactiae (group B)?
- Produces CAMP factor
- Enlarges the area of hemolysis formed by S. aureus
Which G+ bacteria is found in normal colonic flora and can cause UTIs, biliary tract infections, and subacute endocarditis (after GI/GU procedures)?
Enterococci faecalis and faecium (group D)
Enterococci faecalis and faecium (group D)
Characteristics of Enterococci?
Group D Streptococci
- G+
- Penicillin G resistant
Group D Streptococci
- G+
- Penicillin G resistant
What kind of infections do Enterococci cause?
- UTI
- Biliary tract infections
- Subacute endocarditis (following GI/GU procedures)
What kind of bacteria are classified as Group D Streptococci? Difference?
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
What determines whether a bacteria is Group A/B/C/D?
Lancefield grouping - based on differences in the C carbohydrate on the bacterial cell wall, variably hemolysis
What is an important cause of nosocomial infection by Enterococci?
VRE: Vancomycin-Resistant Enterococci
Which G+ bacteria is found in normal colonic flora and can cause bacteremia and subacute endocarditis in colon cancer patients?
Streptococcus bovis (group D)
Characteristics of Streptococcus bovis (group D)?
- Colonizes the gut
- Causes bacteremia and subacute endocarditis in colon cancer patients (Bovis in the Blood = Cancer in the Colon)
- γ-hemolysis (no hemolysis)
- Colonizes the gut
- Causes bacteremia and subacute endocarditis in colon cancer patients (Bovis in the Blood = Cancer in the Colon)
- γ-hemolysis (no hemolysis)
Which bacteria causes pseudomembranous pharyngitis (grayish-white membrane) w/ lymphadenopathy?
Which bacteria causes pseudomembranous pharyngitis (grayish-white membrane) w/ lymphadenopathy?
Corynebacterium diphtheriae - via exotoxin encoded by β-prophage, inhibits protein synthesis via ADP-ribosylation of EF-2
Which bacteria releases diphtheria exotoxin? Mechanism?
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
What are the symptoms of Corynebacterium diphtheriae infection?
- Pseudomembranous pharyngitis (grayish-white membrane)
- Lymphadenopathy
- Myocarditis
- Arrhythmias
How do you diagnose Corynebacterium diphtheriae infection?
- G+ rods w/ metachromatic (blue and red) granules
- Elk test for diphtheria toxin
- Black colonies on cystine-tellurite agar
How can you prevent infection with Corynebacterium diphtheriae?
Toxoid vaccine
Which bacteria form spores?
Spore-forming G+ bacteria in soil:
- Bacillus anthracis
- Clostridium perfringens
- C. tetani

Other spore formers:
- B. cereus
- C. botulinum
- Coxiella burnetti
What causes bacteria that form spores to make spores? Purpose?
- Form spores at the end of the stationary phase when nutrients are limited
- Spores are highly resistant to heat and chemicals
What are the characteristics of spores?
- Highly resistant to heat and chemicals
- Have dipicolinic acid in their core
- No metabolic activity
How do you kill spores?
Must autoclave (as is done to surgical equipment) by steaming at 121°C for 15 minutes
Which bacteria are G+, spore-forming, obligate anaerobic bacilli?
Clostridia
- C. tetani
- C. botulinum
- C. perfringens
- C. difficile
What kind of toxin is produced by Clostridium tetani?
Tetanospasmin / Tetanus toxin (exotoxin)
What bacteria releases Tetanus toxin? Effects?
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)
What is trismus? Cause?
Lockjaw - caused by Tetanus toxin from Clostridium tetani
What is Risus Sardonicus? Cause?
Spasm of facial muscles causing a grin - caused by Tetanus toxin from Clostridium tetani
What kind of toxin is produced by Clostridium botulinum?
Preformed, heat-labile toxin
What bacteria releases a preformed, heat-labile toxin? Effects?
Clostridium botulinum
- Inhibits ACh release at neuromuscular junction, causing botulism
How does C. botulinum infect adults? Infants?
"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
Why shouldn't babies eat honey?
- Honey can contain spores from C. botulinum
- Ingestion of spores causes floppy baby syndrome (toxin inhibits ACh release at neuromuscular junction causing botulism)
What kind of toxin is produced by Clostridium perfringens?
α-Toxin ("lecithinase" a phospholipase)
What bacteria releases α-Toxin? Effects?
Clostridium perfringens
- α-Toxin - a phospholipase
- Causes myonecrosis (gas gangrene) and hemolysis
- Perfringens perforates a gangrenous leg
"PERFringens PERForates a gangrenous leg"
What kind of toxin is produced by Clostridium difficile?
Produces 2 toxins
- Toxin A (enterotoxin)
- Toxin B (cytotoxin)
What bacteria releases Toxin A? Effects?
Clostridium difficile
- Enterotoxin
- Binds to brush border of gut
What bacteria releases Toxin B? Effects?
Clostridium difficile
- Cytotoxin
- Causes cytoskeletal disruption via actin depolymerization → pseudomembranous colitis → diarrhea
What often precedes infection by Clostridium difficile? Symptoms?
- Often secondary to antibiotic use, especially clindamycin or ampicillin
- Causes diarrhea
How do you diagnose Clostridium difficile infection? Treat?
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
What is the only bacterium with a polypeptide capsule (contains D-glutamate)?
Bacillus anthracis
Which bacteria causes Anthrax? Characteristics?
Bacillus anthracis
- G+, spore-forming rod
- Produces anthrax toxin
- Only bacterium with a polypeptide capsule (contains D-glutamate)
Bacillus anthracis
- G+, spore-forming rod
- Produces anthrax toxin
- Only bacterium with a polypeptide capsule (contains D-glutamate)
What are the forms of infection caused by Bacillus anthracis?
- Cutaneous anthrax
- Pulmonary anthrax
What are the symptoms of Cutaneous Anthrax?
- Boil like lesion → ulcer with black eschar (painless, necrotic)
- Uncommonly progresses to bacteremia and death
- Boil like lesion → ulcer with black eschar (painless, necrotic)
- Uncommonly progresses to bacteremia and death
What are the symptoms of Pulmonary Anthrax?
- Inhalation of spores → flu-like symptoms
- Rapidly progresses to fever, pulmonary hemorrhage, mediastinitis, and shock
What is the term for Pulmonary Anthrax caused by inhalation of spores from contaminated wool?
Woolsorters' Disease
Which bacteria causes food poisoning commonly from reheated rice?
Bacillus cereus
What kind of infection is caused by Bacillus cereus? Source of infection?
- 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
What is responsible for the emetic type of food poisoning due to Bacillus cereus? How soon?
Cereulide (preformed toxin) in rice and pasta, causes symptoms within 1-5 hours
How quickly do diarrheal type symptoms from Bacillus cereus occur?
Within 8-18 hours
What bacteria can be found in unpasteurized dairy products and infected deli meats?
Listeria monocytogenes
Characteristics of Listeria monocytogenes?
- G+ facultative intracellular microbe
- Produces LPS (only G+ organism to do so)
- G+ facultative intracellular microbe
- Produces LPS (only G+ organism to do so)
How can Listeria monocytogenes be acquired?
- Ingestion of unpasteurized dairy products and deli meats
- Transplacental transmission
- Vaginal transmission during birth
How does Listeria monocytogenes avoid host defenses?
- 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
What can infection with Listeria monocytogenes cause?
- Amnionitis, septicemia, and spontaneous abortion in pregnant women
- Granulomatosis infantiseptica
- Neonatal meningitis
- Meningitis in immunocompromised patients
- Mild gastroenteritis in healthy individuals
What does Listeria monocytogenes cause in healthy patients? How do you treat?
Gastroenteritis (mild) - usually self-limited
What does Listeria monocytogenes cause in pregnant patients?
- Amnionitis
- Septicemia
- Spontaneous abortion
What does Listeria monocytogenes cause in infants patients? How do you treat?
- Granulomatosis infantiseptica
- Neonatal meningitis (treat with Ampicillin)
What does Listeria monocytogenes cause in immunocompromised patients? How do you treat?
Meningitis (treat empirically with Ampicillin)
Which bacteria form long, branching filaments resembling fungi?
- Actinomyces
- Nocardia
Which bacteria causes oral/facial abscesses that drain through sinus tracts forming yellow "sulfur" granules? How do you treat?
Which bacteria causes oral/facial abscesses that drain through sinus tracts forming yellow "sulfur" granules? How do you treat?
Actinomyces - treat with Penicillin
Actinomyces - treat with Penicillin
Characteristics of Actinomyces?
- G+ anaerobe
- Forms ong-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
- 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
Which bacteria causes pulmonary infections in immunocompromised patients and cutaneous infections after trauma in immunocompromised patients? How do you treat?
Nocardia - treat with Sulfonamides
Characteristics of Nocardia?
- 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 wi...
- 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
What causes Tuberculosis? Different forms of infection?
Infection with Mycobacterium tuberculosis
- Primary infection: non-immune host (usually a child)
- Secondary infection: partially immune hyper-sensitized host (usually adult)
Infection with Mycobacterium tuberculosis
- Primary infection: non-immune host (usually a child)
- Secondary infection: partially immune hyper-sensitized host (usually adult)
What are the signs of a Primary Tuberculosis?
Occurs in a non-immune host (usually a child)
- Ghon Complex: Hilar nodes & Ghon focus (usually in mid zone of lung)
Occurs in a non-immune host (usually a child)
- Ghon Complex: Hilar nodes & Ghon focus (usually in mid zone of lung)
What can Primary Tuberculosis lead to?
- Heals by fibrosis → immunity and hypersensitivity → Tuberculin (+)

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

- Severe bacteremia → miliary tuberculosis → death

- Pre-allergic lymphatic or hematogenous disse...
- 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
What are the signs of a Secondary Tuberculosis?
Fibrocaseous cavitary lesion (usually in upper lobes)
Fibrocaseous cavitary lesion (usually in upper lobes)
What can Secondary Tuberculosis lead to?
Extrapulmonary Tuberculosis
- CNS: parenchymal tuberculoma or meningitis
- Vertebral body: Pott disease
- Lymphadenitis
- Renal
- GI
- Adrenals
Extrapulmonary Tuberculosis
- CNS: parenchymal tuberculoma or meningitis
- Vertebral body: Pott disease
- Lymphadenitis
- Renal
- GI
- Adrenals
What does a positive PPD test mean?
Either:
- Current infection with Mycobacterium tuberculosis
- Past exposure to Mycobacterium tuberculosis
- BCG vaccinated
What does a negative PPD test mean?
Either:
- No infection
- Anergic (steroids, malnutrition, immunocompromise) and in sarcoidosis
Which test is more specific than PPD for Mycobacterium tuberculosis infection?
Interferon-γ Release Assay (IGRA)
- More specific
- Fewer false positives from BCG vaccination
Which vaccine is used to prevent Tuberculosis?
BCG vaccine
What is the appearance of a caseating granuloma in tuberculosis infection?
- Central necrosis (pinkish region in upper left)
- Multinucleated Langhans giant cell (arrow)
- Central necrosis (pinkish region in upper left)
- Multinucleated Langhans giant cell (arrow)
What are the symptoms of TB?
- Fever
- Night sweats
- Weight loss
- Hemoptysis
What are the species of Myocbacterium? What disease do they cause?
- 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)
What are the characteristics of all Mycobacteria?
All are acid-fast organisms
All are acid-fast organisms
Which bacteria causes disseminated, non-TB disease in AIDS patients? Treatment / prevention?
Mycobacterium avium-intracellulare
- Often resistant to multiple drugs
- Prophylactic treatment with Azithromycin
What is released by virulent strains of Mycobacteria? Implication?
Cord fator is found in virulent strains
- Inhibits macrophage maturation
- Induces release of TNF-α

Sulfatides (surface glycolipids)
- Inhibit phagolysosomal fusion
Which bacteria causes this appearance?
Which bacteria causes this appearance?
Mycobacterium leprae (Leprosy / Hansen disease)
Characteristics of Mycobacterium leprae?
- Acid-fast bacillus
- Likes cool temperatures
- Cannot be grown in vitro
- Reservoir in US: armadillos
- Acid-fast bacillus
- Likes cool temperatures
- Cannot be grown in vitro
- Reservoir in US: armadillos
What does Mycobacterium leprae infect?
- Skin 
- Superficial nerves: "glove and stocking" loss of sensation

- Armadillos (reservoir)
- Skin
- Superficial nerves: "glove and stocking" loss of sensation

- Armadillos (reservoir)
What are the forms of Leprosy / Hansen disease? Characteristics?
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
- Charac...
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
Which form of Leprosy has a LOW cell-mediated immunity with a humoral Th2 response?
Lepromatous form
Which form of Leprosy has a HIGH cell-mediated immunity with a largely Th1-type immune response?
Tuberculoid form
How do you treat the two forms of Leprosy / Hansen disease?
Lepromatous form:
- Dapsone, Rifampin, and Clofazimine for 2-5 years

Tuberculoid form:
- Dapsone and Rifampin for 6 months
How should you first distinguish G- (pink) bacteria?
Shape
- Diplococci
- "Coccoid" rods
- Rods
- Oxidase (+) comme shaped
Shape
- Diplococci
- "Coccoid" rods
- Rods
- Oxidase (+) comme shaped
Which bacteria are G- diplococci? How do you distinguish them?
Distinguish based on ability to ferment maltose
- Neisseria meningitidis (ferments maltose - meningitiids starts with "m")
- Neisseria gonorrhoeae (non-fermenter)
Distinguish based on ability to ferment maltose
- Neisseria meningitidis (ferments maltose - meningitiids starts with "m")
- Neisseria gonorrhoeae (non-fermenter)
Which bacteria are G- coccoid rods? How do you distinguish them?
* Haemophilus influenzae (requires factors V and X)
* Bordetella pertussis
- Pasteurella (animal bites)
- Brucella (brucellosis)
* Haemophilus influenzae (requires factors V and X)
* Bordetella pertussis
- Pasteurella (animal bites)
- Brucella (brucellosis)
Which bacteria are G- rods? How do you distinguish them?
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 (+):...
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
Which bacteria are lactose fermenting G- rods? How do you distinguish them?
Fast fermenters:
* Klebsiella
* E. coli
- Enterobacter

Slow fermenters:
- Citrobacter
- Serratia

Lactose is "KEE" - Test with Mac"C"on"KEE'S" agar
Fast fermenters:
* Klebsiella
* E. coli
- Enterobacter

Slow fermenters:
- Citrobacter
- Serratia

Lactose is "KEE" - Test with Mac"C"on"KEE'S" agar
Which bacteria are non-lactose fermenting G- rods? How do you distinguish them?
Oxidase (+):
- Pseudomonas

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

Oxidase (-):
- Shigella
- Salmonella
- Proteus
- Yersinia
Which bacteria are oxidase (+), comma shaped G-? How do you distinguish them?
Grows in 42°C:
- Campylobacter jejuni

Grows in alkaline media:
- Vibrio cholerae

Produces urease:
- Helicobacter pylori
Grows in 42°C:
- Campylobacter jejuni

Grows in alkaline media:
- Vibrio cholerae

Produces urease:
- Helicobacter pylori
How do you determine if a bacteria can ferment lactose?
*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 ...
*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)
Can E. coli ferment lactose? Why or why not?
Yes - E. coli produces β-galactosidase, which breaks down lactose into glucose and galactose
G- bacilli are resistant to what antibiotics? What are they susceptible to?
- Resistant to Penicillin G and Vancomycin (G- outer membrane layer inhibits entry)

- Susceptible to Penicillin derivatives such as Ampicillin and Amoxicillin
Neisseria species are what type of bacteria? What can they ferment?
G- diplococci
- MeninGococci ferment both Maltose and Glucose (meningitidis)
- Gonococci ferment Glucose (gonorrhoeae)
G- diplococci
- MeninGococci ferment both Maltose and Glucose (meningitidis)
- Gonococci ferment Glucose (gonorrhoeae)
What do Neisseria species produce?
IgA proteases
Which bacteria is sexually transmitted and can also cause septic arthritis, neonatal conjunctivitis, pelvic inflammatory disease (PID), and Fitz-Hugh-Curtis Syndrome? Treatment?
Neisseria gonorrhoeae

Treat: Ceftriaxone (+ Azithromycin or Doxycycline for possible Chlamydia co-infection)
Characteristics of Neisseria gonorrhoeae?
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)
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)
What can Neisseria gonorrhoeae infection cause? Prevention?
Prevent sexual transmission w/ condoms
- Gonorrhea
- Septic arthritis
- Neonatal conjunctivitis (prevent transmission w/ erythromycin ointment)
- Pelvic Inflammatory Disease (PID)
- Fitz-Hugh-Curtis Syndrome
Which bacteria is spread via respiratory and oral secretions, causing meningococcemia and meningitis as well as Waterhouse-Friderichsen syndrome? Treatment?
Neisseria meningitidis

Treat: Ceftriaxone or Penicillin G
Characteristics of Neisseria meningitidis?
G- diplococci
- Produces IgA proteases
- Ferments glucose AND maltose
- Polysaccharide capsule
- Vaccine (none for type B)
- Spread via respiratory and oral secretions
G- diplococci
- Produces IgA proteases
- Ferments glucose AND maltose
- Polysaccharide capsule
- Vaccine (none for type B)
- Spread via respiratory and oral secretions
What can Neisseria meningitidis infection cause? Prevention?
- Meningococcemia (picture)
- Meningitis
- Waterhouse-Friderichsen syndrome

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

(Ceftriaxone or Penicillin G can be used for treatment)
- Meningococcemia (picture)
- Meningitis
- Waterhouse-Friderichsen syndrome

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

(Ceftriaxone or Penicillin G can be used for treatment)
Which bacteria causes an infection that leads to the "thumbprint sign" on lateral neck radiograph?
Which bacteria causes an infection that leads to the "thumbprint sign" on lateral neck radiograph?
Haemophilus influenzae epiglottitis
Haemophilus influenzae epiglottitis
Characteristics of Haemophilus influenzae?
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
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
Which type of Haemophilus influenzae causes the most invasive disease? What do the other types cause?
- Most invasive disease caused by capsular type B
- Nontypeable strains cause mucosa infections (eg, otitis media, conjunctivitis, or bronchitis)
What kind of infection is caused by Haemophilus influenzae?
HaEMOPhilus causes
- Epiglottitis ("cherry red" in children)
- Meningitis
- Ototis media
- Pneumonia
HaEMOPhilus causes
- Epiglottitis ("cherry red" in children)
- Meningitis
- Ototis media
- Pneumonia
How do you culture Haemophilus influenzae?
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"
How do you treat Haemophilus influenzae infections?
- Mucosal infections (eg, otitis media, conjunctivitis, bronchitis) with Amoxicillin +/- Clavulanate

- Meningitis with Ceftriaxone
How do you prevent spread / infection of Haemophilus influenzae infections?
- 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)
Which bacteria causes severe pneumonia, fever, GI and CNS symptoms?
Legionella pneumophila (Legionnaire's disease)
Characteristics of Legionella pneumophila?
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...
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)"
How do you diagnose Legionella pneumophila? Other signs?
* 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
How does Legionella pneumophila get spread?
- Aerosol transmission from environmental water source habitat (eg, A/C systems, hot water tanks)
- Not person-to-person
What disease states can Legionella pneumophila infection cause? Treatment?
- Legionnaires' Disease: severe pneumonia, fever, GI and CNS symptoms
- Pontiac Fever: mild flu-like syndrome

- Treat: Macrolide or Quinolone
Which bacteria is associated with wound and burn infections?
Pseudomonas aeruginosa
Characteristics of Pseudomonas aeruginosa?
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)
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)
What toxins does Pseudomonas aeruginosa produce? Effects?
- Endotoxin → fever and shock
- Exotoxin A → inactivates EF-2
What color is Pseudomonas aeruginosa? How?
Blue/green pigment called Pyocyanin
Blue/green pigment called Pyocyanin
What kind of infections does Pseudomonas aeruginosa cause?
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
Which bacteria causes hot tub folliculitis?
Pseudomonas aeruginosa
How does Pseudomonas aeruginosa affect immunocompromised patients?
Ecthyma gangrenosum
- Rapidly progressive
- Large ulcer (arrows)
- Necrotic cutaneous lesions (arrowheads)
Ecthyma gangrenosum
- Rapidly progressive
- Large ulcer (arrows)
- Necrotic cutaneous lesions (arrowheads)
What bacteria is associated with chronic pneumonia in cystic fibrosis patients?
Pseudomonas aeruginosa (associated with biofilms)
What are the virulence factors of E. coli?
- Fimbriae
- K capsule
- LPS endotoxin
What kind of infections are enhanced by the E. coli virulence factor "fimbriae"?
- Cystitis
- Pyelonephritis
What kind of infections are enhanced by the E. coli virulence factor "K capsule"?
- Pneumonia
- Neonatal meningitis
What kind of infections are enhanced by the E. coli virulence factor "LPS endotoxin"?
Septic shock
What are the strains of E. coli?
- EIEC
- ETEC
- EPEC
- EHEC
Which bacteria causes invasive dysentery (severe diarrhea with the presence of blood and mucus in the feces)? Mechanism?
EIEC (Invasive)
- Microbe invades intestinal mucosa and causes necrosis and inflammation
- Clinical manifestation is similar to Shigella
Which bacteria causes Travelers' Diarrhea (watery)? Mechanism?
ETEC (Travelers')
- Produces heat-labile and heat-stable enteroToxins
- No inflammation or invasion
Which bacteria causes diarrhea usually in children? Mechanism?
EPEC (Pediatrics)
- No toxin produced
- Adheres to apical surface
- Flattens villi
- Prevents absorption
Which bacteria causes non-invasive dysentery (severe diarrhea with the presence of blood and mucus in the feces)? Mechanism?
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
What are the components of Hemolytic Uremic Syndrome? Cause?
- 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
What is the difference between EIEC and EHEC?
- 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
Besides the presentation and mechanism, how does EHEC differ from other forms of E. coli?
Does not ferment sorbitol
Which form of E. coli does not ferment sorbitol?
EHEC
Which bacteria is associated with the 4 A's (Aspiration pneumonia, Abscess in lungs and liver, Alcoholics, and di-A-betics)?
Klebsiella
Characteristics of Klebsiella?
G- Rod
- Fast lactose fermenter
- Part of intestinal flora
G- Rod
- Fast lactose fermenter
- Part of intestinal flora
What does Klebsiella cause? Who is affected?
*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
Which bacteria causes patients to have a lobar pneumonia that leads to red "currant jelly" sputum?
Klebsiella
What are the similarities of Salmonella and Shigella?
G- rods
- Invades intestinal mucosa and cause bloody diarrhea
- Do not ferment lactose
- Oxidase (-)
How do Salmonella and Shigella differ in movement?
Salmonella:
- Flagella (salmon swim)

Shigella:
- No flagella
How do Salmonella and Shigella differ in dissemination?
Salmonella
- Hematogenously (salmon swimming)

Shigella
- Cell-to-cell transmission
- No hematogenous spread
How do Salmonella and Shigella differ in reservoirs?
Salmonella
- Many animal reservoirs (salmon is an animal)

Shigella
- Only in humans and primates
How do Salmonella and Shigella differ in production of hydrogen sulfide?
Salmonella
- Produces hydrogen sulfide

Shigella
- Does not produce hydrogen sulfide
How do Salmonella and Shigella differ in their response to antibiotics?
Salmonella
- Antibiotics may PROLONG fecal excretion of organism

Shigella
- Antibiotics SHORTEN duration of fecal excretion of organism
How do Salmonella and Shigella differ in their immune system response?
Salmonella
- Invades intestinal mucosa and causes a MONOCYTIC response

Shigella
- Invades intestinal mucosa and causes a PMN infiltration
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?
Typhoid Fever (caused by Salmonella typhi) - only found in humans
What are the symptoms of Typhoid Fever (Salmonella typhi)?
- Rose spots on abdomen
- Fever
- Headache
- Diarrhea
- Can remain in gallbladder and cause a carrier state
Characteristics of Salmonella?
- 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 ...
- 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
Characteristics of Shigella?
- 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 caus...
- 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
What bacteria is a major cause of bloody diarrhea (especially in children), and is spread through foods such as poultry, meat, and unpasteurized milk?
Campylobacter jejuni
Characteristics of Campylobacter jejuni?
G- Comma or S-shaped
- Oxidase (+)
- Grows at 42°C ("Campylobacter likes the hot campfire")
G- Comma or S-shaped
- Oxidase (+)
- Grows at 42°C ("Campylobacter likes the hot campfire")
How is Campylobacter jejuni acquired?
Fecal-oral transmission through foods such as:
- Poultry
- Meat
- Unpasteurized milk
What does Campylobacter jejuni cause?
- Major cause of bloody diarrhea (especially in children)
- Common antecedent to Guillain-Barré syndrome and reactive arthritis
Which bacteria produces profuse "rice-water diarrhea"? Mechanism? Treatment?
Vibrio cholerae
- Enterotoxin permanently activates Gs → ↑cAMP → rice-water diarrhea
- Treat with prompt oral rehydration
Characteristics of Vibrio cholerae?
G- comma shaped
- Oxidase (+)
- Grows in alkaline media
Where is Vibrio cholerae more common? Treatment?
- Endemic to developing countries
- Prompt oral rehydration is necessary
Which bacteria causes mesenteric adenitis that can mimic Crohn disease or appendicitis? Transmission?
Yersinia enterocolitica
- Transmitted from pet feces (eg, puppies), contaminated milk, or pork
What disease does Yersinia enterocolitica cause? Transmission?
- Mesenteric adenitis that can mimic Crohn disease or appendicitis
- Transmitted from pet feces (eg, puppies), contaminated milk, or pork
Which bacteria causes gastritis and peptic ulcers (especially duodenal)?
Helicobacter pylori
Helicobacter pylori
Characteristics of Helicobacter pylori?
G- comma shaped rods
- Oxidase (+)
- Catalase (+)
- Urease (+) - can use urea breath test or fecal antigen test
- Creates alkaline environment
G- comma shaped rods
- Oxidase (+)
- Catalase (+)
- Urease (+) - can use urea breath test or fecal antigen test
- Creates alkaline environment
What does Helicobacter pylori cause?
- Causes Gastritis and Peptic Ulcers (especially duodenal)
- Risk factor for gastric adenocarcinoma
- Risk factor for lymphoma
How do you treat Helicobacter pylori infection?
Triple therapy:
- Proton Pump Inhibitor (PPI)
- Clarithromycin
- Amoxicillin or Metronidazole
What is the name for spiral-shaped bacteria? Types? Visualization?
What is the name for spiral-shaped bacteria? Types? Visualization?
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)
Which type of bacteria can be visualized with dark-field microscopy?
Treponema (type of spirochete)
Which type of bacteria is found in water contaminated with animal urine?
Leptospira interrogans
What diseases are caused by Leptospira interrogans infection?
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
What is the cause and symptoms of Leptospirosis?
Leptospira interrogans
- Flu-like symptoms
- Jaundice
- Photophobia
- Conjunctival suffusion (erythema without exudate)
What is the cause and symptoms of Weil Disease?
Caused by Leptospira interrogans
AKA icterohemorrhagic leptospirosis
- Severe form of leptospirosis with jaundice and azotemia from liver and kidney dysfunction
- Fever
- Hemorrhage
- Anemia
Who is more likely to get infected with Leptospira interrogans (which causes leptospirosis and Weil disease)?
Prevalent among surfers and in tropics (eg, Hawaii)
What causes Lyme Disease?
* Borrelia burgdorferi, which is transmitted by the tick Ixodes (also vector for Babesia)
- Natural reservoir is the mouse (important for tick life cycle)
Where is Lyme disease more common?
NE United States
What are the initial symptoms of Lyme Disease (Borrela burgdorferi)?
- Erythema chronicum migrans - expanding bulls eye red rash (picture)
- Flu-like symptoms
- +/- Nerve palsy
- Erythema chronicum migrans - expanding bulls eye red rash (picture)
- Flu-like symptoms
- +/- Nerve palsy
What are the later symptoms of Lyme Disease (Borrela burgdorferi)?
- Monoarthritis (large joints)
- Migratory polyarthritis
- Cardiac - AV nodal block
- Neurologic - encephalopathy, facial nerve palsy, polyneuropathy
What mnemonic can you use to remember the symptoms of Lyme Disease?
FAKE a Key LYME pie:
- Facial nerve palsy (typically bilateral)
- Arthritis
- Kardiac block
- Erythema migrans
How do you treat Lyme Disease (Borrelia burgdorferi)?
Doxycycline and Ceftriaxone
What bacteria causes Syphilis?
Treponema pallidum (spirochete)
What are the stages of Syphilis?
- 1° Syphilis
- 2° Syphilis
- 3° Syphilis
- Congenital Syphilis
What are the signs of 1° Syphilis?
Localized disease, presents with PAINLESS chancre
Localized disease, presents with PAINLESS chancre
What are the microscopic and lab findings of 1° Syphilis?
- Dark-field microscopy can visualize treponemes in fluid from chancre
- Serologic testing: VDRL/RPR (non-specific), confirm diagnosis with specific test (eg, FTA-ABS)
What are the signs of 2° Syphilis?
- Disseminated disease / Systemic
- Constitutional symptoms
- Maculopapular rash (palms and soles)
- Condylomata lata (wart like lesions on the genitals)
What are the microscopic and lab findings of 2° Syphilis?
- Dark-field microscopy can visualize treponemes
- Serologic testing: VDRL/RPR (non-specific), confirm diagnosis with specific test (eg, FTA-ABS)
Following the systemic (2° stage) of syphilis, what happens?
Latent syphilis stage
- Positive serology without symptoms
What are the signs of 3° Syphilis?
- 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
What are the lab findings of 3° Syphilis?
For neurosyphilis: test spinal fluid with VDRL or RPR
What are the signs of congenital syphilis?
- Saber shins
- Saddle nose
- CN VIII deafness
- Hutchinson teeth
- Mulberry molars

(spreads typically after first trimester)
How do you prevent syphilis and congenital syphilis?
*Treat with Penicillin G

- Prevent congenital syphilis: treat mother early in pregnancy, as placental transmission typically occurs after 1st trimester
What is the "Prostitute Pupil"? AKA? Sign of?
Argyll Robertson Pupil
- Pupil constricts with accommodation but is not reactive to light
- Associated with 3° syphilis
What is the VDRL test used for? Utility?
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
What is the term for flu-like syndrome that begins after antibiotics are started? Why?
Jarish-Herxheimer Reaction
- Due to killed bacteria releasing pyrogens (produces fever)
What is the Jarish-Herxheimer Reaction?
- Causes flu-like syndrome that begins after antibiotics are started
- Due to killed bacteria releasing pyrogens (produces fever)
What is the term for infectious disease transmitted between animals and humans?
Zoonosis
Which zoonotic species is transmitted by Ixodes ticks? Source? Disease?
Anaplasma species
- Live on deer and mice
- Causes anaplasmosis

Borrelia burgdorferi
- Lives on deer and mice
- Causes Lyme disease
Anaplasma species
- Live on deer and mice
- Causes anaplasmosis

Borrelia burgdorferi
- Lives on deer and mice
- Causes Lyme disease
Which zoonotic species is transmitted by a cat scratch? Disease?
Bartonella species
- Cat scratch disease, bacillary angiomatosis
Bartonella species
- Cat scratch disease, bacillary angiomatosis
Which zoonotic species is transmitted by louse? Disease?
Borrelia recurrentis
- Relapsing fever
- Recurrent due to variable surface antigens

Rickettsia prowazekii
- Epidemic typhus
Borrelia recurrentis
- Relapsing fever
- Recurrent due to variable surface antigens

Rickettsia prowazekii
- Epidemic typhus
Which zoonotic species is transmitted by unpasteurized dairy? Disease?
Brucella specia
- Brucellosis / undulant fever
Brucella specia
- Brucellosis / undulant fever
Which zoonotic species is transmitted by puppies and livestock? Source? Disease?
Campylobacter
- Fecal-oral transmission via ingestion of undercooked meat
- Bloody diarrhea
Campylobacter
- Fecal-oral transmission via ingestion of undercooked meat
- Bloody diarrhea
Which zoonotic species is transmitted by parrots and other birds? Disease?
Chlamydophila psittaci
- Psittacosis
Chlamydophila psittaci
- Psittacosis
Which zoonotic species is transmitted by aerosols of cattle / sheep amniotic fluid? Disease?
Coxiella burnetii
- Q fever
Coxiella burnetii
- Q fever
Which zoonotic species is transmitted by lone star ticks? Disease?
Ehrlichia chaffeensis
- Ehrlichiosis
Ehrlichia chaffeensis
- Ehrlichiosis
Which zoonotic species is transmitted by rabbits? Disease?
Francisella tularensis (also via ticks and deer fly)
- Tularemia
Francisella tularensis (also via ticks and deer fly)
- Tularemia
Which zoonotic species is transmitted by animal urine? Disease?
Leptospira species
- Leptospirosis
Leptospira species
- Leptospirosis
Which zoonotic species is transmitted by armadillos? Disease?
Mycobacterium leprae
- Leprosy
- Also spread by humans with lepromatous leprosy
Mycobacterium leprae
- Leprosy
- Also spread by humans with lepromatous leprosy
Which zoonotic species is transmitted by animal bites (cats, dogs)? Disease?
Pasteurella multocida
- Cellulitis and osteomyelitis
Pasteurella multocida
- Cellulitis and osteomyelitis
Which zoonotic species is transmitted by Dermacentor ticks? Disease?
Rickettsia rickettsii
- Rocky Mountain spotted fever
Rickettsia rickettsii
- Rocky Mountain spotted fever
Which zoonotic species is transmitted by fleas? Disease?
Rickettsia typhi
- Endemic typhus

Yersinia pestis
- Plaque
- Rats and prairie dogs are reservoirs
Rickettsia typhi
- Endemic typhus

Yersinia pestis
- Plaque
- Rats and prairie dogs are reservoirs
Which zoonotic species has a reservoir in rats and prairie dogs? Disease?
Yersinia pestis
- Causes the plague
- Transmitted by fleas
Yersinia pestis
- Causes the plague
- Transmitted by fleas
Which bacteria presents as a gray vaginal discharge with a fishy smell?
Gardnerella vaginalis
Characteristics of Gardnerella vaginalis?
- Pleomorphic
- Gram-variable rod
- Involved in vaginosis
- CLUE cells or vaginal epithelial cells covered with Gardnerella bacteria are visible under the microscope (arrow)
- Pleomorphic
- Gram-variable rod
- Involved in vaginosis
- CLUE cells or vaginal epithelial cells covered with Gardnerella bacteria are visible under the microscope (arrow)
What causes Gardnerella vaginalis?
* Not sexually transmitted
- Associated with sexual activity
- Overgrowth of certain anaerobic bacteria in vagina
How is Gardnerella vaginalis treated?
Metronidazole or (to treat anaerobic bacteria) Clindamycin
What are the vector-born illnesses? Vector?
- 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
How do you treat all Rickettsial diseases and vector-borne illnesses?
Doxycycline
In which Rickettsial diseases and vector-borne illnesses is a rash common?
Rash common:
- Rocky Mountain spotted fever (Rickettsia rickettsii - tick)
- Typhus (R. typhi - fleas (endemic); R. prowazekii - human body louse (epidemic))
In which Rickettsial diseases and vector-borne illnesses is a rash rare?
Rash rare:
- Ehrlichiosis (Ehrlichia - tick)
- Anaplasmosis (Anaplasma - tick)
- Q fever (Coxiella burneii - tick feces and cattle placenta)
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?
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?
Rickettsia rickettsii (Rocky Mountain Spotted Fever)
- Primarily in S. Atlantic states, especially N. Carolina
Characteristics of Rickettsia rickettsii?
Obligate intracellular organisms
- Requires CoA and NAD+ because they can't synthesize ATP
What is the classic presentation of Rocky Mountain Spotted Fever?
Triad: headache, fever, rash (vasculitis)
In which infections is there a "palms and soles" rash?
CARS = you drive CARS using your palms and soles
- Coxsackievirus A infection (hand foot and mouth disease)
- Rocky mountain spotted fever
- 2° Syphilis (systemic)
What are the different causes of Typhus? How do they differ?
Rickettsia typhi
- Endemic
- Spread by fleas

Rickettsii prowazekii
- Epidemic
- Human body louse
What are the symptoms of Typhus?
Rash starts centrally (trunk) and spreads out, SPARING the palms and soles
What are the characteristics of Ehrlichiosis?
- Caused by Ehrlichia - vector is tick
- Monocytes with morulae (berry like inclusions) in cytoplasm (picture)
- Rarely presents with a rash
- Caused by Ehrlichia - vector is tick
- Monocytes with morulae (berry like inclusions) in cytoplasm (picture)
- Rarely presents with a rash
Which disease is pictured: monocytes with morulae (berry-like inclusions) in cytoplasm?
Which disease is pictured: monocytes with morulae (berry-like inclusions) in cytoplasm?
Ehrlichiosis - caused by Ehrlichia (vector is a tick)
Ehrlichiosis - caused by Ehrlichia (vector is a tick)
What are the characteristics of Anaplasmosis?
- Caused by Anaplasma, vector is tick
- Granulocytes with morulae in cytoplasm
- Rarely presents with rash
Which disease is characterized by granulocytes with morulae in cytoplasm?
Anaplasmosis - caused by Anaplasma (vector is tick)
What are the characteristics of Q fever?
- 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
Which bacteria has Elementary bodies and Reticulate bodies?
Chlamydiae
What are the requirements of Chlamydiae?
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
What kind of infections does Chlamydiae cause?
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)
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)
What are the two forms of Chlamydiae?
- 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
Which bacteria causes reactive arthritis (Reiter syndrome), follicular conjunctivitis (picture), non-gonococcal urethritis, and PID?
Which bacteria causes reactive arthritis (Reiter syndrome), follicular conjunctivitis (picture), non-gonococcal urethritis, and PID?
Chlamydiae trachomatis
Which bacteria causes atypical pneumonia and is transmitted by an aerosol?
Chlamydiae pneumoniae and Chlamydiae psittaci (notable for an avian reservoir)
How do you treat Chlamydiae infections?
Azithromycin (favored because one time treatment) or Doxycycline
How do you diagnose Chlamydiae infection?
Lab: cytoplasmic inclusions seen on Giemsa stain or fluorescent antibody-stained smear
What are the Chlamydiae trachomatis serotypes?
- Types A, B, and C
- Types D-K
- Types L1, L2, and L3
Which serotypes of Chlamydiae trachomatis cause chronic infection and can cause blindness due to follicular conjunctivitis? Other characteristics?
Types A, B, and C
- Africa
- Blindness
- Chronic Infection
Which serotypes of Chlamydiae trachomatis cause urethritis / PID, ectopic pregnancy, neonatal pneumonia (staccato cough), and neonatal conjunctivitis?
Types D-K (everything else)
- Neonatal disease can be acquired during passage through infected birth canal
Which serotypes of Chlamydiae trachomatis cause Lymphogranuloma Venereum? Symptoms?
Types L1, L2, and L3
- Small, painless ulcers on genitals
- Swollen, painful inguinal lymph nodes that ulcerate (buboes)
- Treat with doxycycline
Which bacteria is the classic cause of atypical "walking pneumonia"?
Mycoplasma pneumoniae (more common in patients < 30 years old; common outbreaks in military recruits and prisons)
What are the symptoms of "walking pneumonia"? When is this more common? Cause?
- 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
What are the lab results for a patient with "walking pneumonia" caused by Mycoplasma pneumoniae?
- 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
How do you treat "walking pneumonia" caused by Mycoplasma pneumoniae?
Macrolide, Doxycycline, or Fluoroquinolone

(penicillin ineffective since Mycoplasma have no cell wall)
Why will penicillin be ineffective in a case of walking pneumonia?
Typical cause is Mycoplasma pneumoniae (which has no cell wall so penicillin will be ineffective)
Characteristics of Mycoplasma pneumoniae?
- No cell wall
- Not seen on Gram stain
- Bacterial membrane contains sterols for stability