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Block 2 > Bacteria > Flashcards

Bacteria Flashcards

1
Q

Bacterial infection clinical features

A
  • neutrophilia with left shift
  • pyogenic, encapsulated bacterial infections: B-cell deficiency
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2
Q

anaerobic bacteria

A

anaerobes Can’t Breathe Fresh Air:
C - Clostridium
B - Bacteriodes
F - Fusobacterium
A - Actinomyces israelii

these bacteria lack catalase and/or superoxide dismutase, making them susceptible to oxidative damage

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3
Q

obligate intracellular bacteria

A

stay inside when it’s Really Chilly and Cold
R - Rickettsia
Ch - Chlamydia
Co - Coxiella

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4
Q

encapsulated bacteria

A

Please SHiNE my SKiS
P - Pseudomonas
S - Streptococcus pneumoniae
Hi - Haemophilus influenzae
N - Neisseria meningitidis
E - Escherichia coli
S - Salmonella
K - Klebsiella pneumoniae
S - group B Strep

capsules serve as an antiphagocytic virulence factor

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5
Q

Extended-spectrum beta-lactamase-producing bacteria (ESBL)

A

particularly gram-negative bacteria (e.g., Enterobacteriaceae such as Klebsiella spp., Escherichia coli)

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6
Q

Staph aureus lab classification

A

gram positive cocci
catalase +
coagulase +
mannitol-salt agar plate: golden yellow

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7
Q

Staph aureus virulence factors

A

coagulase: clumping factor that binds to fibrinogen
- parting of red sea

protein A: binds to IgG, protects from opsonization and phagocytosis
- A on Moses staff

exfoliative toxins A & B: causes scalded skin syndrome
- bald man with red skin

enterotoxins: cause food poisoning, rapid onset/termination
- nauseous woman on running camel with meats and creams

Toxic Shock Syndrome toxin (TSST-1): superantigen, binds to MHC II and t-cell receptor ==> release of cytokines, leakage of endothelia
- superman cape

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8
Q

staph aureus is found in…

A

nasopharynx mainly, also skin

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9
Q

staph aureus exotoxin-mediated diseases

A

gastroenteritis (food poisoning): acute symptoms result from intoxication; pre-formed toxin that is found in food

Toxic Shock syndrome: localized growth of S. aureus and release of toxin into blood
- patients with nasal packing or superabsorbent tampons

scalded skin syndrome (Ritter’s disease in newborns): result of exfoliatin toxin

impetigo: superficial infection of epidermis; localized SSSS (fluid-filled blisters)

folliculitis: infection around hair follicle

furuncles: boils; large collection of necrotic tissue

bacteriemia: bacteria in blood

acute endocarditis: S. aureus in blood adheres to heart tissues; aggressive form of endocarditis that leads to high mortality
- Strep viridans is 2nd major cause of endocarditis (sub-acute)

osteomyelitis: bone infection with severe pain and fever

septic arthiritis: invasion of the joint

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10
Q

Staph epidermis lab classification

A

gram positive cocci
catalase +
coagulase -
does NOT ferment mannitol

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11
Q

Staph epidermis important facts

A
  • found on skin
  • production of slime layer/biofilms enables colonization of catheters, shunts, artificial valves, artificial joints, etc.
  • Novobiocin sensitive
  • often seen in blood culture contaminations
  • can cause bloodstream infections (sepsis)

plumber with belly button out, fixing slimy pipes

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12
Q

Staph saprophyticus lab classification

A

gram positive cocci
catalase +
coagulase -
does NOT ferment mannitol

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13
Q

staph saprophyticus important facts

A
  • 2nd most common cause of UTIs in young, sexually active women
  • Novobiocin resistant

sexy young woman with belly button covered

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14
Q

Strep pyogenes (Group A Strep) lab classification

A

gram positive cocci (pairs or chains)

catalase -

beta hemolytic, Lancefield group A
- red lightbulb

encapsulated, hyaluronic acid capsule
- Hot Apple pie in glass capsule

bacitracin sensitive
- basset hound

L-pyrrolidonyl arylamidase (PYR) sensitive

treat with Penicillin G
- baker holding pencil

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15
Q

Strep pyogenes (GAS) virulance factors

A

M protein: antiphagocytic factor, Class I associated with rheumatic fever <- antibodies against M protein cross-react with heart cells
- mitral pope hat with M on it

hyaluronic acid capsule: interferes with phagocytosis
- Hot Apple pie in glass capsule

Streptolysin S & O: hemolysins that make pores in host cell membranes

pyrogenic exotoxins: phage-encoded superantigens, cross-link MHC class II to T-cell receptors ==> cytokine storm ==> toxic shock like syndrome
- baker with superman cape

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16
Q

Strep pyogenes (GAS) pyogenic/supperative (pus-producing) diseases

A

pharyngitis: white spots on back of throat, gray furry tongue, swollen uvula
- red handkerchief around baker’s throat

impetigo/pyoderma: superficial skin infection, blisters
- honey crusted pie

erysipelas: infection of dermis, sharply demarcated edge
- red mittens on baker

cellulitis: deeper dermal infection, not sharply demarcated

necrotizing fascitis: flesh-eating disease, often accompanied by Streptococcal toxic shock syndrome (STSS) due to pyrogenic exotoxins
- burnt gingerbread man
- superman cape with bolt

sepsis

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17
Q

Strep pyogenes (GAS) toxin-mediated diseases

A

scarlet fever: diffuse erythematous rash beginning on chest and spreading to extremities, strawberry tongue
- baker eating strawberry, red gingerman

Streptococcal toxic shock syndrome (STSS): phage-encoded superantigens, cross-link MHC class II to T-cell receptors ==> cytokine storm ==> toxic shock like syndrome
- superman cape with bolt

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18
Q

Strep pyogenes (GAS) sequelae diseases

A

acute rheumatic fever/rheumatic fever (ARF/RF): following pharyngeal infection ONLY, antibodies raised against M-protein cross-react with heart tissue; own cells look like they have M-proteins (molecular mimicry)
- mitral hat on baker with M on it
- JONES cupcakes for symptoms: Joints, Nodules, Erythema marginatum, Sydenhams chorea

acute glomerulonephritis (AGN): follows pharyngeal and skin infections; type III hypersensitivity in glomeruli due to antibody-antigen complexes

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19
Q

Strep agalactiae (Group B Strep) lab classification

A

gram positive cocci (pairs or chains)

catalase -

beta hemolytic, Lancefield group B
- red lightbulbs in space

produces CAMP factor, which enlarges zone of hemolysis when plated with S. aureus
- camping tents
- arrow

bacitracin resistant
- basset hound with capsule/helmet

penicillin sensitive
- pencils for landing legs on spaceship (penicillin given to moms intrapartum at least 4hr before delivery to prevent GBS)

polysaccharide capsule

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20
Q

Strep agalactiae (GBS) diseases

A

largest cause of neonatal meningitis, sepsis, pneumonia
- GBS colonizes lower GI tract and genitourinary tract
- colonized mothers at risk for post-partum disease
- mothers screened at 35wk
- colonization can occur in utero, at birth, or during first few weeks of life
- neurologic complications are common

baby wearing meningitis helmet, in red suit (sepsis), coughing; baby coming out of tunnel (vaginal canal)

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21
Q

Strep pneumoniae lab classification

A

gram positive cocci (lancet shaped diplococci)
- double lance

catalase -

alpha hemolytic
- alpha knight tournament

polysaccharide capsule is main virulence factor
- armor

IgA protease is another virulence factor

bile soluble
- mud on horse’s legs

optochin sensitive
- knight’s chin is exposed

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22
Q

Strep pneumoniae diseases

A

pneumonia: bacteria multiply in alveolar spaces

otitis media: middle ear infections in young children

meningitis: young children and adults

bacteremia: bacteria in blood; endocarditis may occur

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23
Q

Strep pneumoniae treatment and vaccines

A

GBS is sensitive to penicillin, but start with broad spectrum antibiotic until GBS diagnosis confirmed

polysaccharide vaccines (PSV) + conjugate vaccines (PCV) available, both now replaced by PCV20

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24
Q

Strep viridans lab classification

A

gram positive cocci
catalase -
alpha hemolytic

optochin resistant
- jester’s mask covers chin

bile resistant
- jester’s shoes on donkey

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25
Q

Strep viridans important facts

A
  • commensal species found in oral cavity (also GI/GU tracts)
  • dental caries
  • dental manipulations can send bacteria into bloodstream ==> repeated buildup ==> sub-acute endocarditis

optochin resistant:
“viridans strep live in the mouth because they are not afraid of-the-chin”

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26
Q

Enterococcus lab classification

A

E. faecalis and E. faecium

gram positive cocci
catalase -
gamma hemolytic

grow in 6.5% NaCl and bile
- resist the 6.5% N.CA sign
- jester’s boots

resistant to most antibiotics, including vancomycin (source of vancomycin resistance in S. aureus)
- protestors resisting arrest, resisting getting put into van

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27
Q

Enterococcus diseases

A

one of the most common nosocomial (hospital origin) infections

  • UTIs
  • wound infections
  • endocarditis
  • bacteremia and sepsis following IV catheters
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28
Q

Streptococcus bovis (Group D Strep)

A

non-Enterococcal Group D Strep, AKA Strep gallolyticus

  • gamma hemolysis (no hemolysis)
  • grows in bile, but NOT 6.5% NaCl
  • colonizes gut
  • colon cancer patients: bacteremia, sub-acute endocarditis

“Bovis in the blood = cancer in the colon”

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29
Q

Bacillus anthracis classification

A
  • gram positive rod, spore-forming; “boxcar” like chains
  • only bacteria with polypeptide capsule (buff Vikings), made of D-glutamate
  • toxin has 3 protein subunits: Protective Antigen (PA), Edema Factor (EF), Lethal Factor (LF)

PA: needed for binding and cell entry
EF: mimics adenylate cyclase ==> increased cAMP
LF: protease that inhibits cell-signaling ==> apoptosis

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30
Q

Bacillus anthracis: inhaled, cutaneous, GI transmission

A

bioterrorism or wool-sorting disease (from animal contact)

Inhaled:
- clinical manifestations: fever, chills, sweats, GI symptoms, headache, malaise, NO CORYZA (runny nose)
- widened mediastinum

Cutaneous:
- eschar: dry, dark dead skin

GI:
- nausea, vomiting, fevers 1-5 days after eating infected meat

Viking standing in middle of burnt fire

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31
Q

Bacillus anthracis treatment

A

doxycycline, fluoroquinolone (ciprofloxacin), amoxicillin

flower and bicycle wheel on Viking ship

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32
Q

Bacillus cereus

A
  • gram-positive rod
  • spore-forming, motile
  • heat-stable enterotoxin (cereulide): nausea and vomiting within hours of eating (reheated rice)
  • heat-labile enterotoxin: diarrhea, symptoms arrive a little later (6-8hr)

Viking eating rice and throwing up

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33
Q

Clostridium classification

A
  • gram positive rod
  • spore-forming
  • obligate anaerobe
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34
Q

Clostridium tetani

A
  • nervous system disorder characterized by muscle spasms due to blocking of inhibitory transmitter release (continuous stimulation)
  • glycine-producing Renshaw cells preferentially targeted
  • lockjaw (rismus): intense, painful spasms of masseter muscles
  • opisthotonus: spasm of spinal extensors
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35
Q

Clostridium tetani treatment and vaccines

A
  • halt toxin production, neutralize unbound toxin, airway protection, control muscle spasms
  • antimicrobials play minor role
  • active immunity through vaccination only: 3 doses of tetanus and diphtheria toxoid immediately upon diagnosis
36
Q

Clostridium botulinum

A

anaerobic heat-resistant spores: germinate in canned foods
- robots made of cans

neurotoxin: most potent known bacterial toxin ==> neuroparalytic syndrome affecting peripheral nervous system only (cannot cross blood-brain barrier), descending paralysis as toxin blocks release of ACh from vesicles (stimulation blocked)
- robots struggling to keep upright

after ingesting raw honey, babies lack gut flora that can outcompete C. botulinum ==> floppy baby syndrome
- robot pouring honey all over baby robot

iatrogenic (within healthcare setting) botulsim: unlicensed Botox

37
Q

Clostridium botulinum treatment

A
  • prompt intubation with mechanical ventilation
  • antitoxin: equine serum heptavalent botulism antitoxin or human-derived botulism immune globulin
38
Q

Clostridium perfringens

A

found in soil
- knocked over dirt

alpha-toxin: phospholipase (lecithinase) that breaks down tissue and cell membranes ==> myonecrosis (gas gangrene: gas produced under tissue and has cracking sound on palpation)
- gas leaking out of motorcycle
- alpha flag

exotoxin: heat-resistant spores in food reproduce in gut ==> release exotoxin ==> slow onset diarrheal illness
- slow sign

IV penicillin G
- woman holding pencil

“perfringens perforates a gangrenous leg”

39
Q

Corynebacterium classification

A

gram positive rod

40
Q

Corynebacterium diphtheriae classification

A
  • gram-positive, non-spore forming
  • club-shaped bacteria
  • mycolic acid on cell wall
  • NOT acid fast
  • cystine-tellurite agar (lipid supplemented)
41
Q

Corynebacterium diphtheria pathogenesis

A

diphtheria toxin: inhibits protein synthesis via ADP-ribosylation of elongation factor (EF-2) ==> cell death
- man playing accordian wearing bow tie

pseudomembrane: fibrinous exudate found in oral pharynx that contains dead tissue, inflammatory cells, bacteria
- kids eating grey cotton candy wrapped in plastic wrap

airway obstruction, lymphopathy: thickening of the neck
- thick bull’s neck

myocarditis: arrhythmias, heart block; lethal
- heart-shaped cape

peripheral and cranial neuropathies: damaged myelin sheaths; top-down symptoms that usually resolve
- sausage-eating man

42
Q

Corynebacterium diphtheria treatment and vaccines

A

treatment: penicillin
- score keeper with pencil

natural infection doesn’t result in protective immunity; recovered patients still need vaccine (DTaP, toxoid vaccine)

43
Q

Listeria classification

A
  • gram positive rod
  • only gram(+) to produce lipopolysaccharide (LPS) endotoxin <- fat Santa
  • non-branching
  • individual rods or short chains
  • motile at cold temperatures: tumbling motility
  • intracellularly, uses actin polymerization to spread from cell to cell (rocket tails) without having to go outside cells
44
Q

Listeria monocytonegenes pathogenesis

A

transmitted in food, even refrigerated food like milk and cheese
- Santa eating milk and cheese

high risk: neonates, elderly, pregnancy, those with severe defects in cell-mediated immunity
- pregnant mom and baby

health adults: febrile diarrhea

immunocompromised/elderly: bacteremia with or without CNS infection

pregnant women: can result in spontaneous abortion

neonates: meningitis

45
Q

Actinomyces classification

A
  • gram positive rods
  • branching filaments (tree branches)
  • obligate anaerobes
  • NOT acid fast
  • part of normal oral flora (also GI, GU tracts)
46
Q

Actinomyces israelli

A

infection associated with dental caries/extractions or gingival disease ==> cervical facies atinomyces infection
- soldier with bandage around head

does NOT respect anatomic borders, so can form sinus tracts (channel from source to skin)
- drain with water

yellow sulfur granules composed of bacteria, tissue debris, neutrophils
- yellow rocks on ground

treatment: penicillin, erythromycin, clindamycin
- solder writing with pencil

47
Q

Nocardia classification

A
  • gram positive rod
  • branching filaments
  • cell wall has mycolic acid (similar to Mycobacteria, but a lot less)
  • weakly acid fast staining (Ziehl-Neelsen stain + carbol fuchsin), decolorized by hydrochloric acid
  • catalase positive
  • exogenous flora found in soil

cowboys playing cards

48
Q

Nocardia asteroides pathology

A

risk factor: defects in cell-mediated immunity (transplant, HIV/AIDS, underlying lung disease)
- cowboy leaning on cane

clinical symptoms:
cavitary lung lesions (cough, SOB); pneumonia
- bullet hitting cowboy’s chest and denting the star

brain abscess (headache, fever, focal neurologic deficits)
- bullet shooting a hole through his hat

cutaneous indurated (hard) lesions and inflammation <- immunocompromised people can get cutaneous disease alone following trauma
- cowprint on cowboy with redness

49
Q

Nocardia treatment

A

trimethoprim-sulfamethoxazole
- eggs on the counter: treat with sulfonamides

prolonged therapy: 12mo

50
Q

almost all gram-negative bacteria have what endotoxin on their cell membranes

A

lipopolysaccharide (LPS)

51
Q

Neisseria spp. classification

A

gram-negative diplococci, often intracellular
- red theme
- double handcuffs

aerobic, oxidase positive
- blue ring

carbohydrate utilization pattern:
N. meningitidis = glucose(+) and maltose(+)
N. gonnorrhoeae = glucose(+) and maltose(-)
- “MeninGococci ferment Maltose and Glucose”

grows on chocolate agar, inhibited on blood agar
- detective holding chocolate bar

Thayer-Martin agar: selective agar with vancomycin, polymixin, nystatin
- Vice city Private Nvestigator (VPN)

Noir series

52
Q

Neisseria meningitidis

A
  • encapsulated; capsule is primary virulence factor
  • primarily colonizes nasopharynx
  • easily spread in areas with a lot of people via respiratory droplets
  • 10% mortality even in healthy patients
  • risk factors: complement deficiency (MAC deficiency), asplenia (lack of spleen, sickle cell disease), history of respiratory tract infections, preterm birth
  • wide range of illness: transient fever, pneumonia, meningitis, meningococcemia, septic shock, disseminated intravascular coagulation (DIC)

Meningococcal meningitis: headache, nuchal rigidity, photophobia, petechial rash, hemorrhage on mucous membranes of soft palate/conjunctiva

Shock & DIC: tachycardia, hypotension, cold extremeties, adrenal infarction, bleeding occurring from skin/mucous membranes/GI tract/respiratory tract

college dorm murder scene

53
Q

Neisseria meningitidis treatment

A

Drug of choice is ceftriaxone, can also use IV penicillin G
- firefighter with 3 axes

patients placed in droplet isolation, continued for 24hr after antibiotics

close contacts will need rifampin
- police with rifle holding back crowd

There IS a vaccine for N. meningitidis

mortality is still high despite treatment

54
Q

Neisseria gonorrheae

A
  • not encapsulated
  • gonococcal infection can be localized (urethritis), localized invasive (pelvic inflammatory disease), or systemic (disseminated gonococcal infection)
  • pelvic inflammatory disease: inflammatory diseases of upper female genital tract (endometritis, salpingitis, etc)
  • diganose with PCR/NAT

Treatment: ceftriaxone
- statue with 3 axes

55
Q

Chlamydia classification

A

3 species pathogenic to humans:
1) Chlamydia trachomatis
2) Chlamydophila psittaci
3) Chlamydophila pneumoniae

  • obligate intracellular organisms (unable to make their own ATP)
  • lack peptidoglycan layer, lacks muramic acid
  • cannot grow on artificial media so PCR/NAT is needed for diagnosis
  • 2 developmental phases: elementary body (infectious form), reticulate body (replicative, non-infectious form)

Elementary body: “Enfectious and Enters cell via Endocytosis, transforms into reticulate body”; extracellular
Reticulate body: “Replicates in cell by fission; Reorganizes into elementary bodies”; intracellular

56
Q

Chlamydia trachomatis biovars (biologic variants)

A

Trachoma biovars
- A, B, Ba, C serovar
- D-K serovar: Urogenital tract disease (urethritis)

LGV biovars
- L1, L2, L3 serovar: lymphogranuloma venereum

affects mucous membranes: urethra, endocervix, endometrium fallopian tubes, anorectum, respiratory tract, conjunctivae

clinical manifestations due to direct destruction of cells during replication, post-inflammatory cytokine response

infection does not confer long-lasting immunity due to antigenic variation

57
Q

Chlamydia trachomatis: lymphogranuloma venereum (LGV)

A
  • caused by LGV serovars L1, L2, L3
  • organisms gain access through small abrasions/lacerations
  • primary lesion: small, painless vesicular lesion that ulcerates; lesion heals in 3-5 days
  • second stage: 1-4wk after primary lesion; enlarged lymph nodes become painful buboes that can rupture and drain

Treatment: doxycycline (21 days)
- erythromycin in pregnant women

58
Q

Chlamydia trachomatis: ocular trachoma

A
  • caused by serovars A, B, Ba, C
  • leading cause of preventable blindness, commonly occurs in children
  • chronic/repeated infection ==> inflammation and follicle formation of entire conjuctiva (turning in of eyelids, scarring, ulceration, blood vessel formation in cornea) ==> blindness
59
Q

Chlamydia trachomatis: urogenital tract disease

A
  • most caused by serovars D-K
  • most common STD reported in USA
  • dual infection with Neisseria gonorrhea is common
  • pelvic inflammatory disease, cervicitis, endometritis, urethritis
  • reactive arthritis: triggered by urethritis, conjunctivitis, polyarthritis

Treatment: doxycycline (7 days)
- bicycle wheel as wheel of ship

60
Q

Chlamydia psittaci

A

causes psittacocis (“parrot fever”) and atypical pneumonia

61
Q

Chlamydia pneumoniae

A

causes atypical pneumonia

62
Q

Haemophilus influenzae classification

A

gram-negative coccobacillus
- pink candy machine shaped like a bullet

chocolate agar: Factor V (NAD+) and X (hematin/hemin), which are found in hemolyzed blood
- chocolate shop, 5 and 10 cent signs
- “hemophilic” influenzae
- can also be grown with Staph aureus, which is beta hemolytic and promotes release of factor V

virulence factors:
capsular polysaccharide
IgA protease: cleaves mucosal IgA

63
Q

Haemophilus influenzae diseases and treatment

A

epiglottis (H. influenzae type b)
- coughing child with red tongue

non-typeable (no capsule):
otitis media
- child sticking fingers in his ears

pneumonia
- child coughing + aerosol spray

Treatment: ceftriaxone and rifampin for close contacts
- coughing boy has 3 axes
- unaffected boy has rifle

Vaccine: capsular polysaccharide conjugated to a protein (only for type b)

64
Q

Pseudomonas classification

A
  • encapsulated gram-negative rod
  • obligate aerobe
  • oxidase positive (blue ring)
  • non-lactose fermenting
  • thrives in hot environments
  • blue-green culture
  • pyocyanin: blue-green pigment that acts as a virulence factor, helps with biofilm formation, generates ROS
  • pyoveridine: blue-green pigment that is an iron-chelating molecule, acts as a virulence factor, helps with biofilm formation
  • exotoxin A: inactivates elongation factor 2 (EF-2) ==> inhibition of protein synthesis ==> cell death (accordion player)
  • endotoxin: fever and shock
  • phospholipase C: helps degrade cell membranes
  • cystic fibrosis
65
Q

Pseudomonas infections

A
  • nosocomial pneumonia and UTI: hospital infections (nurse coughing, chamber pot)
  • bacteremia in hospitalized patients
  • chronic pnuemonias in patients with cystic fibrosis
  • skin infections: burn wound infections, hot tub folliculitis
66
Q

Enterobacterales species

A
  • Escherichia coli: UTIs
  • Klebsiella spp.: pneumonia
67
Q

Escherichia coli

A
  • gram-negative
  • fast lactose-fermenter
  • MacConkey agar (contains lactose); E. coli grows pink
  • green sheen on Eosin-methylene blue (EMB) agar <- stains for gram(-)
  • facultative anaerobic, oxidase negative
  • encapsulated
  • P Fimbriae (aka P pili): adhere to urogenital epithelium
  • K capsule: capsular polysaccharide that inhibits phagocytosis
  • Lipid A and O-antigen of lipopolysaccharide (LPS) endotoxin: shock and fever
68
Q

Klebsiella pneumoniae

A
  • gram-negative
  • fast lactose-fermenter
  • grows pink on MacConkey agar; thick and mucoid
  • natural flora of GI tract
  • capsular polysaccharide: thick capsule reflected in very mucoid colonies seen on agar
  • can cause pneumonia
69
Q

Mycobacteria species

A
  • aerobic
  • weakly gram-positive bacilli
  • acid-fast (Ziehl-Neelsen stain)
  • gold standard is culture: solid (Lowenstein Jensen agar) and liquid media, but takes 6-8wk to culture
  • mycolic acid cell wall (hydrophobic, lipid rich)
  • patient’s cell-mediated immunity is key to prognosis: TH1 response, activation of CD4+ T-cells, secretion of INF-y, macrophage/CD8+ cell response
70
Q

Mycobacterium tuberculosis

A

virulence factors:
cord factor (trehalose dimycolate) and mycolic acid glycolipids elicit granuloma formation by increasing TNF-a (activates other alveolar macrophages) ==> CD4+ T-cells come help, forming collar around macrophages ==> sulfatides prevent phagolysosome fusion ==> ceseating granuloma formation
- cowboy lasso

inhalation of M. tuberculosis into lungs results in latent infection and disease onset many years later (reactivation)
- latent TB: infection without any symptoms = 90% of pts
- reactivation disease: cavitary lung lesion in upper portion of lung

clinical findings:
- fear, weight loss, anorexia, hemoptysis (coughing up blood), drenching night sweats

71
Q

Mycobacterium tuberculosis treatment, hospital procedures

A

airborne isolation: N95 mask
- suspected TB: at lest 3 consecutive sputum specimens collected in 8-24hr intervals

PPD test: purified protein derivative skin test
- false negatives due to immunosuppressive drugs or immunocompromised pts
- false positives due to hx of BCG vaccine

Quantiferon TB Gold In-Tube test/Interferon Gamma Release Assay (IGRA): single blood test, no cross-reactivity with other Mycobacteria
- antigen provided in tube ==> pt’s antigen-presenting cells process antigen ==> APC presents to antigen specific T-cell ==> T-cell produces IFN-y
- detection based on IFN-y amounts
- only tests for latent TB infection, does NOT say if pt has active infection

Bacillus Calmette Guerin (BCG) vaccine:
- attenuated M. bovis
- used in countries where TB is endemic

Treatment:
4 drugs for 2 months, then 2 drugs for 4 months
- RIPE: Rifampin (RIF), Isoniazid (INH), Pyrazinamide (PZA), Ethambutol (EMB)

72
Q

Mycobacterium leprae

A
  • affects the skin, peripheral nerves, upper respiratory tract mucosa, eyes
  • consider in patients with cutaneous lesions + enlarged nerves/sensory loss
  • not very transmissible
  • inhalation of M. leprae from respiratory drops
  • armadillo/Mangabey monkey contact
  • diagnosis: skin biopsy of skin lesion shows acid-fast bacilli (AFB); PCR

Spectrum of leprosy: influenced largely by patient’s immune status
- high cell mediated immunity = tuberculoid disease, paucibacillary leprosy (low AFB load), Th1 response
- low cell mediated immunity = lepromatous leprosy, multibacillary leprosy (high AFB load), Th2 response (inappropriate)

73
Q

Mycobacterium avium complex (MAC)

A

M. avium + M. intracellulare
- asymptomatic colonization, leads to enlarged lymph nodes (lymphadenitis)
- disseminated disease in AIDS patients: most common mycobacterial disease in USA, diagnosis made with blood culture (CD4 < 50cells/mm3); chronic condition (diarrhea, fevers, anemia)
- AIDS-defining illness
- pulmonary disease in immunocompetent patients

74
Q

Mycobacterium marinum

A
  • tuberculosis-like symptoms in fish
  • cutaneous lesions
75
Q

major spirochetes

A
  • Treponema pallidum (syphilis)
  • Borrelia (Lyme disease)
  • Leptospira (leptospirosis, Weil disease)

technically gram-negative, but very weak gram-negative stain and not truly considered gram-negative organisms

76
Q

Borrelia

A

Lyme disease from hard ticks, ixodes
- early Lyme: bulls-eye skin lesion develops at tick bite, called Erythema Chronicum Migrans (ECM)
- late disease: neurologic signs (meningitis, Bell’s palsy), monoarticular arthritis, cardiac

Also causes relapsing fever from body louse or soft ticks; relapsing due to antigenic variation

Treatment: doxycycline
- treat if high clinical suspicion

spiraly wood shavings from arrow

77
Q

Leptospira

A
  • infection via urine-contaminated water and animal exposure (rodents, dogs, domestic/wild animals)
  • severe headaches, flu-like illness, aseptic meningitis, scleral icterus (yellow sclera)
  • Weil’s disease (severe disease): vascular collapse, thrombocytopenia, hemorrhage, liver/kidney failure

Treatment: penicillin or doxycycline

coiled ankle strap on surfboard; yellow sea (pee)

78
Q

Treponema pallidum

A

Syphilis:
Primary syphilis:
- painless chancre
- diagnose with dark-field microscopy

Secondary syphilis:
- disseminated disease: fever, lymphadenopathy (swollen lymphs), maculopapular rash, condyloma lata (painless wart-like lesions on genitals)
- diagnose with nontrepenomal / treponemal tests

Tertiary syphilis:
- gummas (chronic granulomas of skin), aortitis, neurosyphilis
- diagnose with CSF examination (lumbar puncture)

Latent syphilis:
- no clinical symptoms
- diagnose with CSF examination

Congenital syphilis:
- early: hepatomegaly, nasal discharge (snuffles), skeletal abnormalities, rash, lymphadenopathy
- late: saddle nose, sensorineural hearing loss, Hutchinson’s teeth/incisors, mulberry molars, saber shins

Treatment: penicillin G

spiral galaxy at the Pallidum observatory

79
Q

Treponema pallidum testing

A

Dark-field microscopy:
- only for primary syphilis dx

Non-treponemal (non-specific) testing:
- detects anti-cardiolipin antibodies
- used to monitor response to therapy
- can be falsely negative early or late in disease
- false positive with other conditions: (pregnancy, HIV, autoimmune disease, recent immunization, acute febrile illness)
- VDRL
- RPR

Treponemal (specific) testing:
- detect antibodies that specifically target T pallidum
- very specific, positive test remains for life
- TP-EIA
- FTA
- TP-PA
- MHA-TP

80
Q

Major zoonotics

A

Rickettsial diseases:
- Rickettsia rickettsii (Rocky Mountain Spotted Fever)
- Rickettsia akari (pox) from mites
- Rickettsia typhi (typhus) from fleas
- Rickettsia prowazekii (typhus) from body lice
- Ehrlichia chaffeensis (ehrlichiosis)
- Anaplasma phagocytophilum (anaplasmosis)
- Coxiella burnetti (Q fever)

Other:
- Yersinia pestis (bubonic plague)
- Bartonella spp (cat-scratch disease)
- Bartonella quintana / B. henselae (regional lymphadenopathy)
- Francisella tularensis (tularemia)

81
Q

Rikettsia rickettsi

A

Rocky Mountain spotted fever
- dog tick and wood tick
- fever, severe headache, myalgias, rashes on hands/wrists/feet that move to trunk
- severe: pulmonary and renal failure, cardiac and neurologic damage
- 10-25% fatality without treatment

Treatment: doxycycline

82
Q

Anaplasmataceae diseases

A

Ehrlichia chaffeensis
- Lone star tick
- ehrlichiosis: YES rash, leukopenia, high fever, headache
- morulae (berry-like inclusions in cytoplasm) in monocytes
- Central-South USA

Anaplasma phagocytophilum
- Ixodes tick
- high fever, headache, NO rash
- morulae in granulocytes

Treatment: doxycycline

83
Q

Coxiella burnetii

A

Q fever
- infected via aerosols from cattle/sheep amniotic fluids or contaminated milk
- replicates within vacuoles
- most cases are asymptomatic
- symptoms: mild, flu-like symptoms OR pneumonia
- Chronic Q fever: subacute endocarditis in those with underlying valvular heart disease or immunosuppression

Treatment: doxycycline

84
Q

Yersinia pestis

A

Bubonic plague
- Western US with prairie dogs, squireels, rodents; transmitted through fleas
- fevers, headaches, myalgias, painful swollen lymph nodes (buboes)
- diagnosis: bacteria stain bipolar (safety pin appearance)

85
Q

Bartonella spp

A

Bartonella quintana
- non-zoonotic pathogen
- transmitted by humans

Bartonella henselae
- zoonotic
- cat-scratch disease
- regional lymphadenopathy

86
Q

Francisella tularensis

A

Tularemia
- rabbits, ticks
- ulceroglandular: fever, single ulcer with central eschar at site of tick bite

Treatment: streptomycin

Block 2 (10 decks)

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