Microbiology Flashcards
1
Q
Gram positive structure
A
Cell wall present; major surface antigen
Composition:
- Peptidoglycan
- Lipoteichoic acid–> TNF, IL-1 induction
2
Q
Gram negative structure
A
No cell wall, only outer membrane
- Site of Endotoxin= LPS (lipopolysaccharide)= major surface antigen
Composition:
- Lipid A–> activate macrophages–> increased TNF and IL-1
- Antigen= O polysaccharide
- Periplasm= space between cytoplasmic membrane and outer membrane; contains hydrolytic enzymes (beta-lactamases)
3
Q
Spore structure
A
Resistant to dehydration, heat, chemicals
- Must autoclave (121 C for 15 min)
Composition:
- Keratin-like coat
- Dipicolinic acid core
- Peptidoglycan
Seen in:
- Soil: B. anthracis, Clostridium perfringens, c. tetani
- Other: B. cereus, C. botulinum, Coxiella burnetti
4
Q
Gram-positive cocci
A
Staphylococcus
Streptococcus
5
Q
Gram-negative cocci
A
Neisseria
6
Q
Gram-positive rod
A
Clostridium Corynebacterium Bacillus Listeria Mycobacterium (high lipid= acid fast) Gardenerella (gram variable)
7
Q
Gram-negative rods
A
Almost everything else:
- Enterics:
- E. Coli
- Shigella
- Yersinia
- Klebsiella
- Proteus
- Enterobacter
- Serratia
- Vibrio
- Campylobacter
- Helicobacter (silver stain+)
- Pseudomonas
- Bacteroides - Respiratory:
- Haemophilus (pleomorphic)
- Legionella (intracellular; silver stain +)
- Bordetella - Zoonotic
- Francisella
- Brucella
- Pasteurella
- Bartonella
- resistant to Penicillin G (gram-negative outer membrane inhibits Pen G/Vanco from entering)
- Susceptible to Ampicillin, amoxicillin
8
Q
Spirochetes
A
Gram-negative (too thin)
- Leptospira
- Borrelia
- Treponema
9
Q
Pleomorphic bacteria
A
Giemsa-stain
- Rickettsiae (intracellular)
- Chlamydiae (intracellular, no muramic acid)
10
Q
Bacteria with no cell wall
A
Mycoplasma= no staining
- Sterols with no wall
11
Q
Giemsa-positive
A
Certain Bugs Really Try my Patience:
- Chlamydia
- Borrelia
- Rickettsiae
- Trypanosomes
- Plasmodium
12
Q
Carbol Fuschin stain (Ziehl-Neelsen)
A
Acid-fast organisms
- Nocardia
- Mycobacterium
13
Q
India ink positive
A
Cryptococcus neoformans
- can also stain with mucicarmine
14
Q
Exotoxin
A
Derived from gram + and gram -
- Secreted from cell
- Polypeptide
- Located on plasmid/bacteriophage
- Highly toxic
- Antigenic= Induces antitoxins (titer antibodies)
- Vaccine= toxoids
- Destroyed at 60C (besides staph enterotoxin)
Seen in: Tetanus, botulism, diphtheria
15
Q
Endotoxin
A
LPS= structural component of outer cell membrane in gram negative; released when lysed (NOT secreted)
Activates:
- Macrophages:
- IL-1–> fever
- TNF–> fever, hypotension
- NO–> hypotension - Complement
- C3a–> hypotension, edema
- C5a–> neutrophil chemotaxis - Tissue factor
- Coagulation cascade–> DIC
- Located on Bacterial chromosome
- Low toxicity
- Causes: Fever, shock
- Mode of action:Induces TNF and IL-l
- Antigenic: Poorly antigenic
- Vaccines= none
- Stable at 100C for 1 hour
Seen in: meningococcemia, gram-negative sepsis
16
Q
Obligate aerobes
A
Nagging Pests Must Breathe
- Nocardia
- Pseudomonas aeruginosa
- Mycobacterium tuberculosis (apices of lung)
- Bacillus
17
Q
Obligate anaerobes
A
Can’t Breathe Air
- Clostridium
- Bacteroides
- Actinomyces
Seen in GI tract, pathogenic anywhere else
** Can’t treat with aminoglycosides= need O2 to enter cell
18
Q
Obligate intracellulars
A
Rickettsia
Chlamydia
19
Q
Facultative intracellular
A
Now Listen Sally, Yer Friend Bruce Must Leave
- Neisseria
- Listeria
- Salmonella
- Yersinia Pestis
- Francisella
- Brucella
- Mycobacterium
- Legionella
20
Q
Encapsulated bacteria
A
Positive Quellung reaction–> swelling
SHiNE SKiS
- Streptococcus pneumoniae
- Haemophilus infiuenzae type B
- Neisseria meningitidis
- Escherichia coli
- Salmonella
- Klebsiella pneumoniae
- group B Strep.
21
Q
Catalase-positive
A
Degrades H2O2 before converted to microbicidal products by Myeloperoxidase (MPO) PLACESS for your cats: - Pseudomonas - Listeria - Aspergillus - Candida - E. Coli - S. Aureus - Serratia
22
Q
Urease-positive
A
CHuck norris hates PUNKSS:
- Cryptococcus
- H. pylori
- Proteus
- Ureaplasma
- Nocardia
- Klebsiella
- S. epidermidis
- S. saprophyticus
23
Q
IgA protease
A
Enzyme cleaving IgA–> colonize respiratory mucosa: SHiN
- S. pneumoniae
- H. influenza (B)
- Neisseria
** These can all take up naked DNA from environment as well= Transformation
24
Q
Protein A
A
S. Aureus
- Binds Fc region of Ig–> no opsonization/phagocytosis
25
M Protein
Group A strep
| - Prevents phagocytosis
26
Pigment-producing bacteria
Actinomyces Israelii= yellow (Israel= yellow sand)
S. Aureus= yellow (pus/gold)
Pseudomonas aeruginosa= blue/green (pyocyanin)
Serratia marcescens= red (maraschino cherry)
27
Novobicin
Used to ID catalase-positive, coagulase-negative staphylococci
- Staph Saprophyticus= resistant
- Staph Epidermis= sensitive
28
Optochin
used to ID catalase-negative alpha-hemolytic streptococci:
- Viridans= resistant
- Penumoniae= sensitive
29
Bacitracin
Used to ID Catalse-negative, beta-hemolytic streptococci:
- Agalactiae= resistant
- Pyogenes= sensitive
30
Alpha-hemolytic bacteria
Partial hemolysis; green ring around colonies
- Strep pneumo
- Strep viridans
31
Beta-hemolytic bacteria
Complete hemolysis; clear ring around colonies:
- Staph aureus
- Strep pyogenes (group A)
- Strep agalctiae (group B)
- Listeria monocytogenes
32
Staphylococcus aureus
Gram positive cocci, Clustered
Catalase positive
Coagulase positive
Virulence factor= Protein A (binds Fc-IgG--> prevents phagocytosis)
Causes:
1. Inflammatory disease: skin infections, organ abscesses, pneumonia
- Acute bacterial endocarditis
- Osteomyelitis
2. Toxin-mediated disease:
- Toxic shock syndrome (TSST-1)= superantigen, binds MHC II receptor--> T-cell activation--> IFN-gamma, IL-2 release
- scalded skin (exfoliative toxin)
- rapid-onset food poisoning (preformed enterotoxins)
* * Activates T-cells (IL-2) and macrophages (IL-1, TNF)
3. MRSA: resistant to beta-lactams (altered penicillin-binding protein)
Treatment:
- Nafcillin (Naf for Staph- EXCEPT MRSA)
- Vancomycin for MRSA
THINK:
- Pus, empyema, abscess
- Surgical wound
- chronic granulomatous disease (Catalase-positive microbes)
33
Staphylococcus epidermidis
Gram positive cocci
Catalase positive
Coagulase negative
Novobicin sensitive (vs staph saprophyticus)
Infects prostehetic devices, IV catheters (biofilm)
- Seen in normal skin flora
- Contaminates blood cultures
Resistant to penicillins, tx with Vancomycin
34
Staphylococcus saprophyticus
Gram positive cocci
Catalase positive
Coagulase negative
Novobicin resistant (vs staph epidermidis)
Causes UTIs
35
Streptococcus pneumoniae
```
Gram positive cocci; lancet shaped
Catalase negative
alpha-hemolytic
Capsule (+ quelling)
Optochin sensitive (vs strep Viridans)
IgA protease
```
Causes:
- Meningitis
- Otitis media
- Pneumonia (rusty sputum)
- Sinusitis
- Sepsis, splenectomy in Sickle cell
36
Streptococcus viridans
```
Gram positive cocci
Catalase negative
alpha-hemolytic
No capsule
Optochin resistant (vs strep pneumo)
```
Causes:
- Dental caries (normal flora in mouth= strep mutans)
- Subacute bacterial endocarditis (strep sanguis)
37
Strep pyogenes
```
Group A strep
Gram positive cocci
Catalase negative
beta-hemolytic
Bacitracin sensitive (vs strep agalactiae)
```
M-protein (prevents opsonization--> blocking phagocytosis)
Exotoxin=
1. streptolysin O
- Protein degrades cell membrane (lyse RBCs)- test for ASO antibodies
2. Exotoxin A: brings MHC II and T-cell receptors together--> release IFN-gamma, IL-2 release--> Toxic shock-like syndrome
3. Streptokinase= plasminogen activator (blocks clotting)
Causes:
1. Pyogenic:
- Pharyngitis
- Cellulitis
- Impetigo (precedes glomerulonephritis, pharyngitis)
2. Toxigenic:
- Scarlet fever (spares face, strawberry tongue, throat)
- Toxic shock-like syndrome
- Necrotizing fasciitis
3. Immunologic:
- Rheumatic fever (polyarthritis, carditis, subcutaneous nodules, erythema marginatum, Sydenham's chorea)
- Acute glomerulonephritis
- Post strep glomerulonephritis= deficiency of complement due to fixation in renal tubules
* * ASO titer to detect infection (antibodies to streptolysin O)
* * Host antibodies to M-protein--> rheumatic fever
38
Strep agalactiae
```
Group B strep
Gram positive coci
Catalase negative
Beta hemolytic (Produces CAMP factor--> increased hemolysis)
Bacitracin resistant (vs strep pyogenes)
Hippurate test positive
```
Causes:
- Illnesses mainly seen in babies (due to colonization of vaginal flora): Pneumonia, meningitis, sepsis
* * Screen women at 35-37 weeks
- Prophylaxis with penicillin
39
Enterococci
```
Group D strep
Gram positive cocci
Catalase negative
Non-hemolytic/variable hemolysis
Grows in Bile and 6.5% NaCl
```
Enterococci faecalis, faecium:
- Penicillin G resistant
- Cause UTI, biliary tract infections, subacute endocarditis
- Vancomycin-resistant strains= nosocomial infection
40
Streptococcus bovis
```
Group D strep
Gram positive cocci
Catalase negative
Non-hemolytic
Grows in Bile (no NaCl)
```
Colonizes gut
- Colon cancer patients: subacute endocarditis, bacteremia
41
Corynebacterium diphtheriae
Gram positive rod (club-shaped)
Black colonies in cystine-tellurite agar
Metachromatic (blue and red) granules
AB Exotoxin= (B=binds, A= active--> EF-2)
- B-prophage encoded--> inhibits protein synthesis (ADP-ribosylates elongation factor= EF-2)
- Test= Elek's test
Causes:
- Pseudomembranous pharyngitis (gray-white)
- Lymphadenopathy
- Myocarditis
- Arrhythmias
** Toxoid vaccine= induces production of IgG against exotoxin B (toxin causes disease, not bacteria)
42
Clostridium tetani
Gram-positive rod
Spore-forming
Obligate anaerobe
Exotoxin= Tetanospasmin
- Tetanus toxin--> cleaves neurotransmitter-releasing proteins (SNARE)
- Blocks glycine, GABA release (inhibitory neurotransmitters) from Renshaw cells in spinal cord
- Causes spastic paralysis, trismus (lockjaw), risus sardonicus)
Tx: passive vaccine
43
Clostridium botulinum
Gram-positive rod
Spore-forming
Obligate anaerobe
Exotoxin= botulinum toxin
- Cleaves SNARE proteins (blocking neurotransmitter release)
- Inhibits ACh release at NM junction--> flaccid paralysis
- Adults= ingest preformed toxin
- Babies= spores in honey--> floppy baby)
Tx: passive vaccine
44
Clostridium perfringens
Gram-positive rod
Spore-forming
Obligate anaerobe
Exotoxin= alpha toxin (lecithinase= phospholipase)
- Phospholipase degrades tissue, cell membranes-->
- Causes myonecrosis (gas gangrene)
- Hemolysis
45
Clostridium difficile
Gram-positive rod
Spore-forming
Obligate anaerobe
Exotoxins:
1. Toxin A = enterotoxin binding brushborder of gut)
2. Toxin B = cytotoxin binding enterocytes--> pseudomembranous colitis
- Secondary to antibiotics (clindamycin, ampicillin)
Treatment:
- Metronidazole
- Oral vancomycin
46
Bacillus anthracis
Gram-positive rod
* Polypeptide capsule (D-glutamate containing)
Spore-forming
Exotoxin= anthrax (Edema factor)
- Mimics adenylate cyclase (increased cAMP)
- Calmodulin-dependent adenylate cyclase--> increases cAMP in smooth muscle--> vasodilation (edema), suppressed neutrophil funciton)
Forms:
- Cutaneous--> black eschar (painless ulcer)--> bacteremia, death)
- Pulmonary--> flu-like symptoms--> fever, pulmonary hemorrhage, mediastinitis, shock (Woolsorter's disease)
47
Bacillus cereus
Gram-positive rod
Spore-forming
Obligate aerobe
Enterotoxin= Cereulide
- Food poisoning (enterotoxin in rice= "reheated rice syndrome)
- Emesis: rice, pasta--> N/V in 1-5 hours
- Diarrhea: GI pain, watery, non-bloody in 8-18 hours
48
Listeria Monocytogenes
Gram positive rod
Facultative intracellular
Catalase positive
Beta hemolytic
Forms "actin rockets"--> move cell to cell
- Tumbling motility
Ingested from unpasteurized milk/cheese, deli meats
Causes:
- Amnionitis
- Septicemia
- Spontaneous abortion
- Meningitis in immunocompromised
- Gastroenteritis in healthy (self-limited)
Vaginal transmission
Causes:
- Granulomatosis infantiseptica
- Neonatal meningitis
* Tx= ampicillin
49
Actinomyces
```
Long, branching filament (resembles fungi)
Gram-positive
Anaerobe
NOT acid-fast
Found in normal oral flora
```
Causes:
- Oral/facial abscesses that drain--> sinus tracts
- Yellow "sulfur granules"
Tx: Penicillin
50
Nocardia
```
Long, branching filament (resembles fungi)
Gram-positive
Aerobe
Acid fast
Found in soil
```
Causes:
- Pulmonary infections in immunocompromised
- Cutaneous infections (post-trauma) in healthy
Tx: Sulfonamides
51
Mycobacterium tuberculosis
Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion
Primary TB:
- Nonimmune host infected--> Ghon complex:
1. Heals (fibrosis)--> immunity/hypersensitivity
2. Progressive lung disease (immune compromised)
3. Severe bacteremia--> Miliary TB
4. Preallergic lymphatic/hematogenous dissemination--> dormant--> reactivate later in life
Secondary TB:
- Partially immune hypersensitized host (adult) reinfected)
1. Fibrocaseous cavitary lesion (upper lobes)
2. Reactivates
Reactivated TB= Extrapulmonary TB
- CNS (parenchymal TB/meningitis in base of brain)
- Vertebral body (Pott's disease)
- Lymphadenitis
- Renal
- GI
Symptoms:
- Fever, night sweats, weight loss, hemoptysis
Tx:
- Prophylaxis= Isoniazid (INH)
- Therapy= Rifampin, Isoniazid, Pyrazinamide, Ethambutol (RIPE for tx)
52
Mycobacteria Kansasii
Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion
Pulmonary TB-like symptoms
53
Mycobacterium avium-intracellulare
Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices)
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion
Disseminated non-TB disease in AIDS, resistant to multiple drugs
** Prophylaxis with azithromycin (CD4+ < 50)
Tx: Azithromycin, Rifampin, Ethambutol, Streptomycin
54
Mycobacterium leprae
Gram-positive rod
Carbol-Fuschin (Ziehl-Neelsen) stain
Acid fast (lipid membrane)
Obligate aerobe (lung apices), likes cool temps
Facultative intracellular
* Cord factor in virulent strain--> TNF-alpha release, inhibited macrophage maturation
* Sulfatides (surface glycolipids) inhibit phagolysosomal fusion
Reservoir in USA= armadillos
Causes Leprosy. 2 forms:
1. Lepromatous= lethal
- Communicable
- Low cell-mediated immunity, humoral Th2 response only
Tx: Dapsone, rifampin, clofazimine (2-5 years)
2. Tuberculoid= hypoesthetic hairless skin plaques ("glove and stocking" loss of sensation)
Tx: Dapsone, Rifampin (6 months)
55
Lactose-fermenting enteric bacteria
Gram-negative rods
Grow pink colonies on MacConkey's agar:
Fast fermenter= Lactose in KEE
- Klebsiella
- E. coli
- Enterobacter
Slow fermenter=
- Citrobacter
- Serratia
56
Neisseria Gonococci
Gram-negative diplococci
Ferments Glucose (Gonococci)
Produces IgA proteases
Facultative intracellular
Grown on special agar: Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and TMP-SMX)
- NO vaccine available (rapid antigenic variation in pilus)
- STD
Causes:
- Septic arthritis
- Neonatal conjunctivitis
- PID
- Fitz-Hugh-Curtis syndrome (adhesions due to PID; infection of liver capsule)
Tx: Ceftriaxone (+ azithromycin/doxycyclin for chlamydia coinfection)
57
Neisseria Meningococci
```
Gram-negative diplococci
Ferments Maltose and glucose (MeninGococci)
Produces IgA proteases
Facultative intracellular
Encapsulated (polysaccharide capsule)
```
Grown on special agar: Thayer-Martin agar (or VPN agar)—an agar plate containing antibiotics (vancomycin, colistin, nystatin, and TMP-SMX)
- Vaccine (none for Type B)
- Found in respiratory, oral secretions
Causes:
- Meningococcemia
- Meningitis
- Waterhouse-Friderichsen syndrom
Tx: Ceftriaxone, Pen G
** Rifampin, ciprofloxacin, ceftriaxone in close contacts
58
Haemophilus Influenza
```
Gram negative
Coccoid rods
Requires factor V and X to grow in culture (chocolate agar)
IgA protease
Encapsulated
```
- Vaccine= type B capsular polysaccharide conjugated to diphtheria toxoid (2-18 months)
- Nontypable strains cause mucosal infections (no vaccine available)
Causes:
- Epiglottitis (cherry red)
- Meningitis
- Otitis media
- Pneumonia
Tx: Ceftriaxone (meningitis)
* Rifampin prophylaxis in close contacts
THINK:
- Pediatric infection (epiglottitis)
59
Legionella pneumophilia
Gram-negative rod
Facultative intracellular
Silver stain
Grown on charcoal yeast extract with iron, cysteine
- Aerosol transmission from water source
- Detected in urine
- Labs show hyponatremia
Causes:
- Legionnaire's disease= severe pneumonia, fever, GI, CNS symptoms
- Pontiac fever= mild flu-like syndrome
Tx: Macrolide (protein synthesis), quinolone (topoisomerase II)
60
Pseudomonas aeruginosa
```
Gram negative rod (enteric)
Obligate aerobe
Catalase positive
Lactase NON-fermenting
Oxidase positive
Blue-green pigment, grape-like odor
```
Motile, oxidase positive
Produces:
- Endotoxin (fever, shock)
- Exotoxin A (inactivates EF-2)
- Elastase (breaks down vessel walls)
```
Causes: PSEUDOmonas
- Pneumonia (chronic in CF pts due to biofilm)
- Sepsis
- External otitis
- UTI
- Drug use
- Osteomyelitis (diabetic/drug user)
+ Hot tub foliculitis, wound/burn infections
+ MEO in diabetics
```
Tx:
- Aminoglycoside + extended-spectrum penicillin (piperacillin, ticarcillin)
61
Enteroinvasive E. Coli (EIEC)
Gram-negative rod
Lactose fermenting
Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)
Mechanism:
- Invades intestinal mucosa--> necrosis, inflammation
Manifestation: similar to Shigella
- Invasive
- Dysentery (blood, pus in stool)
62
Enterotoxigenic E. Coli (ETEC)
Gram-negative rod
Lactose fermenting
Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)
Mechanism:
- Labile toxin: overactivates adenylate cyclase--> increased cAMP--> Cl- secretion in gut--> H20 moves out of cells
- Stable toxin: overactivates guanylate cyclase--> increased cGMP--> decreased resorption of NaCl /H20 in gut
- NO inflammation/invasion
Manifestation: traveler's diarrhea
63
Enteropathogenic E. Coli (EPEC)
Gram-negative rod
Lactose fermenting
Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)
Mechanism:
- Adheres to apical surface, flattens villi
- Prevents absorption
Manifestation:
- Pediatric diarrhea
64
Enterohemorrhagic E. Coli (EHEC)
Gram-negative rod
Lactose fermenting
Virulence factors:
- P fimbriae (cystitis/pyelonephritis)
- K-1 capsule (pneumonia, neonatal meningitis)
- LPS endotoxin (septic shock)
Mechanism:
- O157:H7= most common--> Shiga-like toxin
- Shiga-like toxin (SLT)= inactivates 60S ribosomal subunit by removing adenine from rRNA
- Endothelial swelling, narrowed lumen--> hemolysis, reduced renal blood flow
- Damaged endothelium--> thrombocytopenia
Cuases:
- Dysentery (Shiga-like)
- Hemolytic-uremic syndrome (HUS) due to cytokine release in response to SLT--> vascular damage--> capillary thrombus formation--> anemia, thrombocytopenia, acute renal failure, increased bleeding time
65
Klebsiella
Gram negative rod
Lactose fermenter
Polysaccharide capsule (mucoid colonies)
4As:
- Aspiration pneumonia
- Abscess (lungs/liver)
- Alcoholics
- diAbetics
* can also cause nosocomial UTI: positive urease test
66
Salmonella
```
Gram negative rod
Lactose non-fermenter
Oxidase negative
Facultative intracellular
Encapsulated
```
- Flagellated
- Hematogenous dissemination
- Animal reservoir
- Produce hydrogen sulfide
- Invades intestinal mucosa--> monocytic response
Causes:
- Bloody diarrhea
- Non-typhoidal= appendicitis mimicker
- Typhi= Typhoid fever (humans only): rose spots on abdomen, fever, headache, diarrhea
- Osteomyelitis in sickle cell pts
Tx: Antibiotics prolong symptoms
67
Shigella
Gram negative rod
Lactose non-fermenter
Oxidase negative
Shiga toxin= inactivates 60S ribosomal subunit by removing adenine from rRNA
- No flagella
- Cell to cell transmission
- Reservoir= humans/primates
- Invades intestinal mucosa--> PMN infiltration
- Shiga toxin--> Cytokine release--> HUS: due to cytokine release in response to Shige toxin--> vascular damage--> capillary thrombus formation--> anemia, thrombocytopenia, acute renal failure, increased bleeding time
Tx: antibiotics shortens excretion of organism in feces
68
Campylobacter jejuni
Gram negative comma-shaped
Oxidase positive
Grows at 42C
Transmitted through poultry, meat, unpasteurized milk
Causes:
- Bloody diarrhea (esp. children)
- Guillain-Barre syndrome, reactive arthritis
- Mimics appendicitis
69
Vibrio cholerae
Gram negative comma-shaped
Oxidase positive
Grows in alkaline media
Mechanism:
- Cholera toxin Activates Gs of adenylate cyclase--> increased cAMP--> increased Cl- secretion, H20 efflux
Causes:
- Profuse rice-water diarrhea (common in developing countries)
Tx: rehydration
70
Yersinia enterocolitica
Gram negative rod
Facultative intracellular
Mechanism:
- Transmitted from pet feces, contaminated milk, pork
Causes:
- Mesenteric adentitis (Crohn's, appendicitis mimicker)
71
H. Pylori
Curved Gram-negative rod
Silver stain
Urease positive (urease breath test)- alkaline environment created in stomach
Causes:
- Gastritis
- 90% duodenal ulcers
- Increased peptic ulcer, gastric adenocarcinoma, B-cell lymphoma risk
Tx: triple therapy:
- PPI
- Clarithromycin
- Amoxicillin/ Metronidazole
72
Spirochetes
Borrelia (BIG)= Wright/Giemsa stain
Leptospira
Treponema= dark field microscopy
73
Leptospira interrogans
Spirochete
Water contaminated with animal urine (triathletes in tropics)
Causes:
- Flu-like symptoms
- Jaundice
- Photophobia with conjunctivitis
- Weil's disease= icterohemorrhagic leptospirosis: severe; jaundice, azotemia (liver, kidney dysfunction), fever, hemorrhage, anemia
74
Borrelia Burgdorferi
Spirochete (visualized with Wright/Giemsa stain)
Lyme disease:
- Transmitted by Ixodes tick
- Reservoir= wood mouse
- Stages:
1. Erythemia migrans (bull's eye), flu-like
2. Neurologic (Bell's palsy), cardiac (AV node block)
3. Musculoskeletal (chronic monoarthritis, migratory polyarthritis), neurological (encephalopathy, polyneuropathy), cutaneous
75
Treponema Pallidum
Spirochete
- Visualized by dark-field microscopy
- Screened with VDRL, confirmed with FTA-ABS
Syphillis:
1. Primary: localized painless chancre (treponemes)
2. Secondary: disseminated disease
- Constitutional symptoms
- Maculopapular rash
- Condylomata lata (treponemes found on warty lesions)
3. Tertiary:
- Gummas (chronic granulomas)
- Aortitis (vaso vasorum destruction)
- Neurosyphilis (tabes dorsalis)
- Argyll-Robertson pupil (non-reactive, accomodative)
- Signs: broad-based ataxia, + Romberg, Charcot joint, stroke w/o HTN
- Treponemes in spinal tap
Congenital syphilis:
- Saber shins
- Sadle nose
- CNVII deafness
- Hutchinson's teeth
- Mulberry molars
* * VDRL= nonspecific; can also indicate:
- Viruses
- Drugs
- Rheumatic fever
- Lupus, leprosy
Tx: Pen G
- Can lead to Jarisch-Herxheimer reaction (killed bacteria release pyrogens)- administer steroids, low dose antibiotics
76
Bartonella
Cat scratch disease
| - Can cause bacillary angiomatosis in immune compromised
77
Borrelia Recurrentis
Recurrent fever
Source: Louse
78
Brucella
Gram negative rod
Facultative intracellular
Causes: Undulent fever
Source: unpasturized dairy
79
Chlamydia psittaci
Obligate intracellular organism (cannot make own ATP)
- Giemsa positive
- Pleomorphic
Elementary body= Enters cell via Endocytosis
Reticulate body= replicates in cell via fission (seen on tissue culture)
- Cytoplasmic inclusions on Giemsa, fluorescent antibody
Psittacosis (pneumonia)
Source: parrots, birds
Tx:
- Azithromycin (one time)
- Doxycycline
80
Coxiella burnetii
Q fever
Source: aerosol of cattle, sheep amniotic fluid
- Survives in soil for years (spore)
Tx: Doxycycline
81
Ehrlichia chaffeensis
Monocyte with morula (berry-like) inclusion in cytoplams
Ehrlichiosis
Source: lone star tick
Tx: Doxycycline
82
Francisella tularensis
Tularemia
Source: ticks, rabbits, deer fly
83
Pasteurella multocida
Cellulitis, osteomyelitis
Source: animal bite (cat, dog)
84
Rickettsia prowazekii
Obligate intracellular
Need CoA and NAD+
```
Epidemic typhus (pro-WAr)
- Rash sparing palms and soles
```
Source: louse
Tx: Doxycycline
85
Rickettsia Typhi
Obligate intracellular
Need CoA and NAD+
Endemic typhus
Source: fleas
Tx: Doxycycline
86
Yersinia pestis
Facultative intracellular
Plague
Source: fleas (rats/prairie dogs= reservoir)
87
Gardenerella vaginalis
Gram-variable pleomorphic rod
"Clue cells" on vaginal swab
KOH prep= fishy smell
Causes: Bacterial vaginitis
- Non-painful, smelly
- Not STD (associated with sexual activity)
Tx: Metronidazole
88
Rickettsia Rickettsii
Obligate intracellular
Need CoA and NAD+
Causes:
- Rocky Mountain Spotted Fever (Broad distribution)
- Rash: wrists, ankles--> trunks, palms, soles
- Headache, fever
89
Anaplasma
Anaplasmosis:
| Granulocytes with morula in cytoplasm
90
Chlamydia trachomatis
Obligate intracellular organism (cannot make own ATP)
- Giemsa positive
- Pleomorphic
Elementary body= Enters cell via Endocytosis
Reticulate body= replicates in cell via fission (seen on tissue culture)
- Cytoplasmic inclusions on Giemsa, fluorescent antibody
```
Causes:
Reiter's syndrome:
- Reactive arthritis
- Conjunctivitis
- Nongonococcal urethritis
- PID
```
Serotypes:
- A, B, C= chronic infection--> follicular conjuntivitis--> blindness (ABC= Africa, Blindness, Chronic infection)
- D-K= Urethritis/PID, ectopic pregnancy, neonatal pneumonia (staccato cough), neonatal conjunctivitis)
- L1, L2, L3= lymphogranuloma
Tx:
- Azithromycin (one time)
- Doxycycline
91
Mycoplasma pneumoniae
No cell wall (no stain)
- Sterol membrane (stability)
Atypical "walking" pneumonia
- Insidious onset, H/A, nonproductive cough, diffuse interstital infiltrate
- IgM titer--> agglutinate, lyse RBCs
Tx: macrolide, fluoroquinolone
92
Bordetella pertussis
Pertussis toxin
- Overactivates adenylate cyclase--> increased cAMP (disables Gi)--> impairs microbial phagocytsosis
Causes:
- Whooping cough= cough on expiration, whoop on inspiration
93
Histoplasmosis
```
Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission
```
Location:
- Mississippi, Ohio river valleys
- Bird/bat droppings in CAVES
Causes: pneumonia
- Hilar adenopathy
Histo: Macrophage filled with histo (Histo hides in macrophages)
Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B
94
Blastomycosis
```
Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission
```
Location:
- States East of Mississippi river, Central America
Causes: inflammatory, lung disease
- Disseminates to skin, bone
- Granulomatous nodules
Histo: broad-based budding (Blasto Buds)
Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B
95
Coccidioidomycosis
```
Dimorphic fungi (20C= cold mold, 37C= heat SPHERULE)
- Can mimic TB with no person-person transmission
```
Location:
- SW USA, California (Valley fever)
Causes: pneumonia, meningitis
- Disseminate to skin, bone
- Increased cases after earthquakes
Histo: Spherule filled with endospores (larger than RBC)
- Coccidio crowds
Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B
96
Paracoccidioidomycosis
```
Dimorphic fungi (20C= cold mold, 37C= heat yeast)
- Can mimic TB with no person-person transmission
```
Location: Latin America (Paracoccdio parasails with Captain's wheel all the way to Latin America)
Histo:
- Budding yeast, captain's wheel formation
Tx:
- Local= fluconazole, itraconazole
- Systemic= Amphotericin B
97
Tinea Versicolor
Malassezia furfur
- Lipid degradation--> acids--> malanocyte damage--> hypo/hyperpigmented areas
- Seen in hot, humid weather
Histo:
- "spaghetti and meatball" on KOH
Tx:
- Topical miconazole
- Selenium sulfide (Selsun Blue)
98
Candida albicans
Tx:
- Topical azole for vaginal infection
- Fluconazole/capsofungin for oral/esophageal
- Fluconazole, ampho B, caspofungin for systemic tx
99
Aspergillus Fumigatus
Invasive= immunocompromised, chronic granulomatous disease
Allergic broncopulmonary (ABPA)= Asthma, CF
Aspergillomas in lung cavities (post-TB)
** Produce aflatoxins= associated with Hepatocellular carcinoma
100
Cryptococcus neoformans
Encapsulated (crypt) yeast
- Found in soil, pigeon droppings
- Inhaled, hematogenous dissemination to meninges
Culture:
- Sabouraud's agar
- India Ink stain
- Latex agglutination= polysaccharide capsular antigen
Can cause meningitis ("soap bubble lesions" in brain) in immune-compromised (AIDS patients with CD4+ < 50)
Tx:
- Amphotericin B + Flucytosine
101
Pneuomcystis jirovecii
PCP= diffuse interstitial pneumonia
- bilateral CXR
- Dx= biopsy, lavage
- Disc-shaped yeast on methenamine silver stain
Tx: TMP-SMZ, pentamidine, dapsone
- Prophylax with CD4+ < 200
102
Sporothrix schenckii
Dimorphic
Cigar-shpaed budding yeast
"Rose-pickers" thumb= pustule, ulcer with nodules along lymphatic drainage
Tx: itraconazole, potassium iodide (plant a rose in the pot)
103
Giardia Lamblia
Trophozoite
Giardiasis: bloating, flatulence, foul-smelling, fatty diarrhea
Transmission: cysts in water
Dx: stool: trophozoites, cysts
Tx: Metronidazole (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)
104
Entamoeba histolytica
Trophozoite
Amebiasis: bloody diarrhea (dysentery), liver abscess (anchovy paste exudate), RUQ pain (flask-shped ulcer if submucosal colon abscess ruptures)
Transmission: cysts in water
Dx: Serology, trophozoites (with phagocytosed RBCs) or cysts (multinucleated) in stool
Tx: Metronidazole (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)
- Iodoquinol for asymptomatic carriers
105
Cryptosporidium
AIDS patients: severe diarrhea
- Milder (watery diarrhea) in immunocompetent
Transmission: Cysts in water)
Dx: Cysts on acid-fast stain
Tx: Prevent (filter water)
- Nitazoxamide in immunocompetent
106
Toxoplasma Gondii
HIV: brain abscess (ring-enhancing lesions)
Congenital: Triad= chorioretinitis, hydrocephalus, intracranial calcifications
Transmission: cysts in meat, cat feces
Dx: Serology, biopsy
Tx: Sulfadiazine, pyrimethamine
107
Naegleria Fowleri
Rapidly fatal meningoencephalitis
Transmission: swimming in freshwater lakes, Netti pot (cribiform plate--> brain)
Dx: Amoebas in CSF
Tx: Amphotercin (maybe?)
108
Trypanosoma brucei gambiense
West African Sleeping sickness:
- Slowly progressive fevers, wasting, late neuro symptoms
- Recurrent fevers: due to Variable Surface Glycoproteins (change with each generation--> immune system can't keep up)
Transmission: Tsetse fly (painful bite)
Diagnosis: blood smear
Tx:
Blood borne= Suramin
CNS= Melarsoprol
"Sure is nice to go to sleep. Melatonin helps with sleep"
109
Trypanosoma brucei rhodesiense
East African sleeping sickness:
- More severe, rapid progression (recurrent fevers--> neurological disease--> coma--> death)
Transmission: Tsetse fly (painful bite)
Diagnosis: blood smear
Tx:
Blood borne= Suramin
CNS= Melarsoprol
110
Plasmodium vivax/ovale
Malaria: fever, H/A, anemia, splenomegaly
- 48 hr cycle (fever on 1st, 3rd day)
- Dormant form in liver
Transmission: Mosquito
Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites
Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)
- **Add primaquine (test for G6PD) to kill hypnozoites in liver
111
Plasmodium falciparum
Malaria: fever, H/A, anemia, splenomegaly
- Severe, irregular fever
- Parasitized RBCs occlude brain capillaries--> cerebral malaria, kidneys, lungs
Transmission: Mosquito
Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites
Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)
112
Plasmodium malariae
Malaria: fever, H/A, anemia, splenomegaly
- 72 hour cycle of fever
Transmission: Mosquito
Diagnosis: Blood smear
- Trophozoite ring
- RBC schizont with merozoites
Tx:
- Chloroquine (blocks heme ploymerase)
- Mefloquine for resistant strains
- Life-threatening: IV quinidine (test for G6PD)
113
Babesia
Babesiosis: fever, hemolytic anemia
- Seen in NE USA
- Increased risk of severe disease in asplenia
Transmission: Ixodes tick
Diagnosis: blood smear (ring form, "Maltese cross), PCR
Tx: Atovaquone + azithromycin
114
Trypanosoma cruzi
Chagas' disease: dilated cardiomyopathy, megacolon, megaesophagus
Transmission: Reduviid bug ("kissing bug")- painless bite--> feces enter wound
Diagnosis: Blood smear
Tx: Nifurtimox
115
Leishmania donovani
Visceral leishmaniasis: spiking fevers, hepatosplenomegaly, pancytopenia
Transmission: sandfly
Diagnosis: macrophages with amastigotes
Tx: sodium stibogluconate
116
Trichomonas Vaginalis
Vaginitis: foul-smelling, greenish discharge
- Itching, burning
Transmission: sexual (must have host- no cyst form)
Diagnosis: Trophozoites (motile) on wet mount
- Strawberry cervix
Tx: Metronidazole (patient and partner) (GET on the Metro: G= giardia, E= entamoeba, T= Trichomonas)
117
Enterobius Vermicularis
Pinworm
Intestinal infection--> anal pruritis ("Scotch tape test")
Transmission: food contaminated with eggs
Tx: Bendazoles, pyrantel pamoate ("Bendy" worms)
118
Ascaris Lumbricoides
Giant roundworm
Intestinal infection
Transmission: Fecal-oral; see eggs under microscope
Tx: Bendazoles, pyrantel pamoate
119
Strongyloides stercoralis
Intestinal infection: N/V, diarrhea, anemia
Transmission: **larvae in soil penetrate skin**
Tx: Albendazole, ivermectin
120
Ancylostoma duodenale, Necator Americanus
Old world, new world hookworm
Intestinal infection--> anemia (suck blood) (microcytic anemia)
Transmission: **larvae penetrate skin**
Treatment: Bendazoles, pyrantel pamoate
121
Dranunculus medinensis
Skin inflammation, ulceration
Transmission: drinking water
Tx: slow extraction of worm
122
Onchocerca volvulus
"River blindness": microfilariae migrate to eye--> die--> inflammatory response--> opacity
- Hanging groin
- Lymphadenopathy
- Allergic reactions
Transmission: Female black fly
Tx: Ivermectin (Iver for River blindness)
123
Loa Loa
Swelling in skin, pain and edema in eye (worm in conjunctiva)
Transmission: female deer fly (horse, mango fly)
Treatment: Diethycarbamazine
124
Wucheria bancrofti
Blocks lymphatic drainage--> elephantiasis (~1 year after bite)
Transmission: female mosquitoes (night)
Tx: Diethylcarbamazine
125
Toxocara canis
Visceral larval migrans: granulomas in viscera (including CNS)--> death from respiratory failure, cardiac arrhythmias, brain damage
Transmission: food contaminated with eggs (carried by cats, dogs)
Tx: Albendazole, mebendazole
126
Taenia Solium
Cestode (tapeworm)
1. Ingestion of larvae in undercooked pork--> Intestinal infection
Tx: Praziquantel
2. Ingestion of eggs (fecal-oral)--> Cysticercosis, neurocysticercosis
Tx: Praziquantel, bendazoles for neurocysticercosis
127
Diphyllobothrium latum
Cestode (tapeworm)
Vitamin B12 deficiency (tapeworm competes for B12 in intestine)--> anemia
Transmission: Ingestion of larvae from raw freshwater fish
Treatment: Praziquantel
128
Echinococcus granulosus
Cestode (tapeworm)
Ingestion of eggs (dog feces)
Cysts in liver (anaphylyaxis if released--> pretreat with ethanol injection before removing)
Tx: Bendazoles
129
Schistosoma
Trematode
- Liver and spleen granulomas, fibrosis, inflammation
* * S. haematobium--> SCC of bladder
* * S. Mansoni--> portal HTN
Transmission: Snails= host--> cercariae penetrate skin
Tx: praziquantel
130
Clonorchis sinensis
Trematode= Chinese liver fluke
- Biliary tract inflammation--> pigmented gallstones
* Associated with cholangiocarcinoma
Transmission: undercooked fish
Tx: Praziquantel
131
Paragonimus Westermani
Trematode
- Lung inflammation; secondary bacterial infection--> hemoptysis
Transmission: undercooked crab meat
Tx: Praziquantel
132
Live, attenuated vaccines
```
Smallpox
Yellow fever
Chicken pox (VZV)
Sabin's polio virus
MMR (only one can be given to HIV+ patients without immune deficiency)
Influenza (flumist nasal spray)
```
133
Killed vaccines
Rabies
Influenza
Salk Polio
HAV
134
Recombinant vaccine
HBV: antigen= recombinant HBsAg
HPV: 6, 11, 16, 18
135
RNA viral genomes
* All are ssRNA except Reoviridae
* All replicate in cytoplasm except Retrovirus (diploid ssRNA), influenza
+ ssRNA:
I went to a RETRO(virus) TOGA(virus) party, where I drank FLAVored(flavivirus) CORONA(virus) and ate Hippy(hepevirus) CALIfornia (calcivirus) PICkles (picornavirus)
136
DNA viruses
All dsDNA, linear, icosahedral, replicate in nucleus:
```
Hepadna (circular, incomplete)
Herpes
Adeno
Pox (complex, has DNA-dependent RNA polymerase--> replicates in cytoplasm)
Parvo (ssDNA)
Papilloma (circular, supercoiled)
Polyoma (circular, supercoiled)
```
137
Herpesviruses
Enveloped
dsDNA, linear
```
HSV1= oral, Spontaneous temporal lobe encephalitis, keratoconjunctivitis
HSV2= genital
HSV3= VZV= chickenpox
HSV4= EBV= mono, Burkitt's, Hodgkin's, nasopharyngeal carcinoma
HSV5= CMV= AIDS retinitis, congenital defects (latent in mononuclear cells= "owl's eyes")
HSV6= roseola
HHV7= roseola (less common)
HHV8= Kaposi's sarcoma
```
Diagnosis:
1. PCR (#1)
2. Tzanck test= smear of opened vesicle (used for HSV1, 2, VZV)
- See **intranuclear Cowdry A inclusions**
3. Monospot (EBV): heterophile antibodies on agglutination of sheep/horse RBCs
- Atypical lymphocytes= reactive cytotoxic T cells
138
Hepadnavirus
Enveloped
dsDNA, partial circular
Hep B:
- Acute or chronic (incubation= months)
- Vaccine= recombinant (HBsAg)
- Contains reverse transcriptase (NOT retrovirus)= DNA-dependent DNA polymerase
- Uses host RNA polymerase--> viral proteins
Transmission: Parenteral, sexual, maternal-fetal
Serology:
- HBsAg= infected (acute/chronic)
- Anti-HBs= immunity (vaccine/recovered)
- HBcAg= antigen to core (infected)
- Anti-HBc= positive during infection (IgM= acute/recent, IgG= prior/chronic)
- HBeAg= Active (acute/chronic)
- Anti-HBe= Window, chronic (low infectivity, recovery)
* * Risk of HCC
* * ALT > AST (vs alcoholics: AST > ALT
139
Adenovirus
Non-enveloped
dsDNA, linear
Pharyngitis, hemorrhagic cystitis
Pneumonia
Conjunctivitis
140
Parvovirus
Non-enveloped
ssDNA, linear negative (smallest DNA virus)
B19= "slapped cheeks" (erythema infectiosum), 5th disease
- In SC pts--> aplastic crisis
- In uteros--> hydrops fetalis
- Adults: RBC aplasia, RA symptoms
141
Papillomavirus
Non-enveloped
dsDNA, circular
HPV:
1, 2, 6, 11= warts
16, 18= CIN, cervical cancer
** Recombinant vaccine
Diagnosis:
- Koilocytes on Papanicolaou smear (pap smear)
142
Polyomavirus
Non-enveloped
dsDNA, circular
- JC virus= PML in HIV
- BK virus= transplant patients, kidney targeted (Bad Kidney)
143
Poxvirus
Enveloped
dsDNA, linear (largest DNA virus)
Smallpox= germ warfare
Vaccinia= cowpox
Molluscum contagiosum= flesh-dome lesion with central dimple
144
Reovirus
Nonenveloped
dsRNA, linear
Icosahedral
Coltavirus= colorado tick fever (arbovirus)
Rotavirus:
- villus destruction, atrophy--> decreased Na absorption, loss of K+
145
Picornavirus
Non-enveloped
ssRNA+, linear
Icosahedral
PERCH:
Poliovirus
Echovirus (aseptic meningitis)
Rhinovirus (common cold)
Coxsackievirus (aseptic meningitis, herpangina, hand foot mouth disease, myocarditis)
HAV (acute Hep A virus): asymptomatic, acute, alone (no carriers)
** All but Rhino (acid-labile) are fecal-oral enteroviruses
146
Hepevirus
Non-enveloped
ssRNA+, linear
Icosahedral
Hep E
- Transmission= fecal-oral (waterborne epidemics)
- No carrier state, short incubation, no HCC
- Enteric, Expectant mothers (bad), Epidemic
147
Calcivirus
Non-enveloped
ssRNA+, linear
Icosahedral
Norovirus
148
Flavivirus
Enveloped
ssRNA+, linear
Icosahedral
Hep C:
- Transmission= blood, IVDU, post-transfusion
- Long incubation
- HCC risk
- Chronic, Cirrhosis, Carcinoma, Carrier
Yellow fever (arbovirus): fever, black vomit, jaundice
Dengue (arbovirus)
St. Louis Encephalitis (arbovirus)
West Nile (arbovirus)
149
Togavirus
Enveloped
ssRNA+, linear
Icosahedral
Rubella (German measles)
- Postauricular lymphadenopathy, arthralgias, truncal rash (head--> trunk)
- Mild in children, serious congenital disease
Eastern Equine Encephalitis (arbovirus)
Western Equine Encephalitis (Arbovirus)
150
Retrovirus
Enveloped
ssRNA+, linear
Icosahedral (HTLV--> T-cell leukemia)
Complex conical (HIV--> AIDS)
** contain reverse transcriptase
HIV:
* envelope proteins acquired by budding from host plasma membrane= ENV
- Env glycosylation--> gp160--> cleaved in ER/golgi--> gp120, gp41
1. gp120= docking glycoprotein*;
- attach to host CD4+ cell (early= CCR5, late= CXCR4)
- attach to CCR5/CD4 on host macrophages
- CCR5 mutation--> immunity (homo), slow course (hetero)
2. gp41= transmembrane protein*; fusion and entry
3. p17= matrix protein
4. p24= capsid protein: GAG
5. reverse transcriptase: POL
Diagnosis:
1. ELISA= rule out (high false-positive)
2. Western Blot= rule in (high false-negative)
3. PCR for viral load
4. CD4+ count (< 200= AIDS) or CD4/CD8 < 1.5
151
Coronaviruses
Enveloped
ssRNA+, linear
Helical
Corona= common cold, SARS
152
Orthomyxoviruses
Enveloped
ssRNA- , linear, 8 segmented
Helical
Influenza:
- Hemagglutin= viral entry
- Neuraminidase= progeny virion release
- Genetic shift/antigenic shift= pandemics (high frequency recombination) ex: swine and human virus recombine
- Genetic drift= epidemics (minor, random mutation)
153
Paramyxovirus
Enveloped
ssRNA-, nonsegmented
Helical
Parainfluenza (croup)
RSV (bronchiolitis in babies, Rx= Ribavirin)
Measles:
- Cough--> conjunctivitis-> spots--> Maculopapular rash: head to toe
- Koplik spots (buccal mucosa)
- Delayed encephalitis (SSPE)
- Giant cell pneumonia (immune suppressed)
Mumps: (makes your parotids and testes as big as POM poms)
- Parotitis
- Orchitits
- Meningitis
* * surface F (fusion) protein= respiratory epithelial cells fuse--> multinucleated cells
- Use Palivizumab (MAB against F) to prevent RSV in premies)
154
Rhabdovirus
Enveloped
ssRNA-, linear
Helical
RABIES!:
- Bullet-shaped
- Negri bodies= cytoplasmic inclusions in neurons (Purkinje of Cerebellum)
- Post-exposure prophylaxis= Wound cleansing + Rabies Ig
- Bite--> nerve axons--> CNS--> salivary glands
155
Filovirus
Enveloped
ssRNA-, linear
Helical
Ebola/Marburg hemorrhagic fever
156
Arenaviruses
Enveloped
ssRNA-, circular segments
Helical
Lymphocytic Choriomeningitis Virus (LCMV)
Lassa Fever encephalitis (mouse-borne)
157
Bunyaviruses
Enveloped
ssRNA-, circular segmets
Helical
California encephalitis (Arbovirus)
Sandfly/Rift valley fever (Arbovirus)
Crimean-Congo hemorrhagic fever (Arbovirus)
Hantavirus--> hemorrhagic fever, pneumonia
158
Delta virus
Enveloped
ssRNA-, cricular
Hep D:
Defective (needs HBV for coinfection)
- Transmission: parenteral, sexual, maternal-fetal
- Short superinfection, long coinfection
159
Negative stranded viruses
```
Must transcribe negative strand to positive:
Always Bring Polymerase Or Fail Replication
- Arenavirus
- Bunyavirus
- Paramyxovirus
- Orthomyxovirus
- Filovirus
- Rhabdovirus
```
160
Segmented viruses
RNA viruses: BOAR
- Bunyaviruses
- Orthomyxoviruses
- Arenaviruses
- Reoviruses
161
Systemic symptoms of HIV infection
Histoplasma capsulatum (pulm symptoms only in immune competent): low grade fever, hepatosplenomegaly, tongue ulcer
- CD4 < 100
- Oval yeast cells in macrophages
162
Dermatologic symptoms of HIV infection
C. albicans (thrush): cottage-cheese lesions
- oral: CD4 < 400
- esophageal: CD4< 100
- Pseudohyphae
Bartonella henselae: superficial vascular proliferation
- Neutrophilic inflammation
163
GI symptoms of HIV
Cryptosporidium: chronic watery diarrhea
- CD4 < 200
- Acid-fast cysts in stool
164
Neurologic symptoms of HIV
JC virus: encephalopathy
- CD4 < 200
Toxoplasma: abscesses
- CD4 < 100
Cryptococcus neoformans: Meningitis
- CD4 < 50
CMV: Retinitis
- CD4 < 50
Dementia due to HIV
165
Oncologic processes in HIV
HHV8: Kaposi's sarcoma
- Lymphocytic inflammation
EBV:
1. hairy leukoplakia (tongue);
2. non-Hodgkin's lymphoma (large cell)- seen on Waldeyer's ring
3. CNS lymphoma (focal or multiple)
HPV: Squamous cell carcinoma (anus, cervix)
166
Respiratory processes in HIV
CMV: Interstitial pneumonia
- Owl's eye intranuclear inclusions
Aspergillus: invasive
- pleuritic pain, hemoptysis, infiltrate on imaging
Pneumocystis jirovecii: Pneumonia
- CD4 < 200
Mycobacterium aviium intracellulare: TB-like
- CD4 < 50
- Prophylax with azithromycin
167
CD4 < 200
1. Pneumocystis jirovecii: Pneumonia
2. JC virus: encephalopathy
3. Cryptosporidium: chronic watery diarrhea
168
CD4 < 100
1. C. albicans (esophageal thrush): cottage-cheese lesions
2. Toxoplasma: abscesses
3. Histoplasma capsulatum (pulm symptoms only in immune competent): low grade fever, hepatosplenomegaly, tongue ulcer
169
CD4 < 50
1. CMV: Retinitis
| 2. Cryptococcus neoformans: Meningitis
170
Prion diseases
PrPc= normal cellular prion protein
PrPsc= Beta-pleated form; transmissible
- Accumulation--> spongiform encephalopathy (dementia, ataxia, death)
Creutzfeld-Jacob= sporadic, rapidly progressive dementia
Gerstmann-Straussler-Scheinker= inherited
Acquired= Kuru, New Variant CJD
171
Normal flora in body
Skin= staph epidermidis
Nose= staph epidermidis, colonized by s. aureus
Oropharynx= viridans group strep
Dental plaque= strep mutans
Colon= Bacteroides fragilis > e. coli
Vagina= lactobacillus; colonized by e. coli and group B strep
172
Bugs causing food poisoning
Vibrio parahaemolyticus, vulnificus= contaminated seafood (wounds for vulnificus)
Bacillus cereus= reheated rice
S. aureus= meats, mayonnaise, custard; preformed toxin
Clostridium perfringens= reheated meat
C. botulinum= improperly canned food
E. coli= undercooked meat (O157:H7)
Salmonella= poultry, meat, eggs
173
Bloody diarrhea
```
Campylobacter
Salmonella
Shigella
EHEC
EIEC
Yersinia enterocolitica
Entamoeba histolytica
```
174
Watery diarrhea
```
ETEC (Stable and Labile toxins)
Vibrio
C. Diff (can also have blood)
C. perferingens
Protozoa (giardia, crypto)
Noro, Rotavirus
```
175
Common causes of pneumonia neonates
Group B strep
| E. coli
176
Common causes of pneumonia: children
```
RSV/ viruses
Mycoplasma
Chlamydia trachomatis
C. pneumoniae
Streptococcus pneumonia
```
"Runts May Cough Chunky Sputum"
177
Common causes of pneumonia: adults 18-40
Mycoplasma
C. pneumoniae
S. pneumoniae
178
Common causes of pneumonia: adults 40-65
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S. pneumoniae
H. influenzae
Anaerobes
Viruses
Mycoplasma
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179
Common causes of pneumonia: elderly
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S. pneumoniae
Influenza
Anaerobes
H. influenzae
Gram-negative rods
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180
Common causes of meningitis: newborns
Group B strep
E. coli
Listeria
181
Common causes of meningitis: children (6 months-6 years)
Strep pneumo
N. meningitidis
H. flu type B
Enteroviruses
182
Common causes of meningitis in 6-60 year olds
S. pneumo
N. meningitidis
Enteroviruses
HSV
183
Common causes of meningitis in 60+ years
S. pneumo
Gram-negative rods
listeria
184
Meningitis: CSF findings
Bacterial= normal pressure, PMNs, increased protein, decreased sugar
Fungal/TB= normal pressure, Lymphocytes, increased protein, decreased sugar
Viral= normal pressure, lymphocytes, normal/elevated protein, normal sugar
185
UTI findings
Predisposition:
- Women (10x more common)
- Males= congenital defects in infants, vesicoureteral reflux
- Elderly males= enlarged prostate
Diagnostics:
- Bacterial UTI= positive leukocyte esterase
- Gram-negative UTI= positive nitrite test
Causes:
1. E. coli
2. Staph saprophyticus
3. Klebsiella pneumoniae (urease positive)
- Serratia marascens= nosocomial, drug resistant
- Enterobacter cloacae= nosocomial, drug resistant
- Proteus mirabilis= motile, "swarm" in agar; urease positive--> struvite stones
- Pseudomonas= nosocomial, drug resistant
186
ToRCHeS
Toxoplasma:
- triad: chorioretinitis, hydrocephalus, intracranial calcifications
Rubella:
- triad: Septal defects/PDA/pulmonary artery hypoplasia or stenosis, cataracts, deafness (+/- "blueberry" rash)
CMV:
- Hearing loss, seizures, petechial rash, "blueberry" rash
HIV:
- Recurrent infections, chronic diarrhea
Herpes Simplex Virus 2:
- Encephalitis, herpetic lesions
Syphillis:
- Stillbirth, hydrops fetalis, facial abnormalities (Hutchinson's teeth, saddle nose, short maxilla), saber shins, deafness (CNVIII)
