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Bacteria and Abx Flashcards

1
Q

Most common cause of septic arthritis

A

S. Aureus

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2
Q

IV drug user with endocarditis?

A

S. Aureus (Tricuspid is the valve most affected)

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3
Q

Most common cause of osteomyelitis in adults

Most common cause of osteomyelitis in IV drug users

Most common cause of osteomyelitis in Sickle Cell Disease

Most common cause of osteomyelitis in sexually active

A

Adults: S. Aureus

IV drug users: Pseudamonas (and diabetics), and Candida (S. Aureus still common)

Sickle Cell Disease: Salmonella

Sexually active: Neisseria gonorrhea (rare)

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4
Q

Rapid onset food poisoning with vomiting as predominant symptom

A

S. Aureus due to preformed toxin release usually from meats/mayo left out too long.

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5
Q

Nafcillin

A

used to treat non-MRSA S. Aureus “naff for staff”

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6
Q

Treatment of MRSA

A

Vancomycin (Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors. Bactericidal. Not susceptible to β-lactamases)

or Metronidazole

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7
Q

Staphylococcus Aureus basics

A

Gram positive cocci in clusters (think grapes), catalase +, coagulase positive, ferments manitol salt, Protein A is virulence factor usually colonizes the nares.

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8
Q

Staphylococcus epidermidis basics

A

Gram + Cocci

Infects prosthetic devices and indwelling catheters -most common cause of endocarditis affecting implanted heart valves -produces adherent biofilm -on normal skin flora, so often shows up positive on blood cultures when not actually infected

Novobiocin sensitive, coagulase negative, catalase positive (all staphs are)

Tx: vancomycin

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9
Q

Staphylococcus saprophyticus

A

Gram + Cocci

Second most common cause of uncomplicated UTI in young women ( rst is E. coli) Novobiocin resistant

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10
Q

Staph vs strep

A

staph is catalase positive

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11
Q

Streptococcus pyogenes (group A streptococci) can cause 3 pyrogenic infections

A

Gram + cocci

Impetigo, Strep throat, Cellulitis/erisipelas

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12
Q

Strep pyrogenase toxin (strep pyrogenous exotoxin, SPE) can cause

A
  1. scarlet fever (pharyngitis, red tongue, wide spread rash) 2. Toxic shock-like syndrome (superantigen) 3. Necrotizing fasciitis (flesh eating bacteria) (SPE-B)
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13
Q

Rheumatic fever overview

A

Inflammatory disease that can develop after inadequately treated strep pharyngitis infections M protein is main virulence factor -interferes with opsonization -very antigenic (strong humoral response- AB to myosin in heart)…effects mitral valve most often

Type II Hypersensitivity reaction (antibody mediated)

Acute rheumatic fever causes mitral regurgitation, while chronic can cause valvular stenosis.

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14
Q

Rheumatic fever symptoms

A

JONES criteria

J: joints –> polyarthritis

O: heart –> endocarditis/pericarditis

N: nodules (subcutaneous)

E: erythema marginatum

S: sydenham’s chorea

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15
Q

Post-streptococcal glomerulonephritis

A

caused by prior infection ( 2 weeks) with specific nephritogenic strains of group A beta-hemolytic streptococcus. The clinical presentation of PSGN varies from asymptomatic, microscopic hematuria to the full-blown acute nephritic syndrome, characterized by red to brown urine, proteinuria (which can reach the nephrotic range), edema, hypertension, and acute kidney injury

Type III Hypersensitivity Reaction (complement activation)

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16
Q

Post-strep glomerulonephritis vs. Rheumatic fever

A

RF only after pharyngitis

PSGN most common after superficial skin infection (impetigo)

Early dx and treatment can prevent RF but NOT PSGN (can still get this no matter what)

Can test ASO titer to see about a previous infection with Strep (useful for diagnosis of RF)

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17
Q

poststreptococcal glomerulonephritis biopsy

A

elevated ASO, decreased serum C3, immunofluorescence shows granular subepithelial deposits composed of IgG, IgM, and C3

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18
Q

Streptococcus agalactiae (group B streptococci)

A

Causes serious infections in babies (number one cause of meningitis in neonates). Also cause sepsis and pneumonia

Capsulated, CAMP test + , Hippurate test +, Beta hemolytic, bacitracin resistant (GAS is bacitracin sensitive)

Acquire GBS through vaginal canal (35 week need to colonize mother for group B strep)

-Give MOM intrapartum PCN (prophylactically)

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19
Q

Streptococcus pneumoniae overview and MOPS

A

1 cause of community acquired pneumonia, causes rust colored sputum (lobar pneumonia)

Gram + Cocci, alpha hemolytic , encapsulated (virulence factor), optochin sensitive, lancelet shape gram + dipplococci, bile soluble

M: meningitis

O: otitis media (children)

P: pneumonia

S: sinusitis

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20
Q

Streptococcus pneumoniae tx and vaccine

A

Macrolide, 3rd generation Cephalosporin (Ceftriaxone)

Two vaccines

23 valent adult IgM response

7 valent child IgG response

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21
Q

Streptococus Viridans

A

Gram + Cocci

No capsule, optochin resistant, bile resistant

normal flora of the oropharynx that cause dental caries (Streptococcus mutans) and subacute bacterial endocarditis at damaged heart valves (S. sanguinis)

Adheres to platelets

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22
Q

Enterococcus (Group D Strep)

A

Gram + Cocci

Two types: E. faecalis (more common) and E. faecium (more severe)

Bile resistant (boots), and can grow in 6.5% NaCl

“DO U HEART TREES”

U: UTI

Heart: endocarditis

Trees: Biliry tree infection

A nosocomic infection that is resistant to almost every abx we have

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23
Q

Enterococcus tx

A

A nosocomic infection that is resistant to almost every abx we have

VRE: vancomycin resistant enterococcus (D-ala D-lac) –> alters the cell wall peptidoglycan

Can use Linezolid or tigecycline to tx enterococcus

If no resistance, Ampicillin is first line treatment. Gentamycin may be added in cases of endocarditis

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24
Q

Bacillus anthracis

A

Gram + Bacilli, Obligate arobe,encapsulated poly D (made of protein, NOT polysaccharides),Spores can survive a very long time

Associated with Black Eschar

Two toxins:

  1. EF (edema factor) functions as edema –> cAMP
  2. LF: responsible for tissue necrosis. MAP kinase causes black eschar

causes pulmonary hemorrhage (nearly 100% death) via mediastinis and shock

Tx: floroquinolones, doxycycline

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25
Q

Bacillus cereus

A

Gram + Bacilli

Usually associated with food poisoning. Spores survive cooking rice. Keeping rice warm results in germination of spores and enterotoxin formation.

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26
Q

Clostridium Tetanus

A

Gram + Bacilli

Obligate Anerobe, spore forming

Puncture wound with rust

Causes a spastic paralysis (in contrast to botulinum)

Toxin travels retrograde to spinal cord, cleaves SNARE, inhibits glyceine and GABA (inhibit the inhibitors, get spastic) in Renshaw cells

Vaccine is toxoid vaccine so produce antibody response to toxin not to organism

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27
Q

Clostriudium Botulinum

A

Gram + Cocci

Transmitted by improper canning of foods (preformed toxin).

Spore forming, obligate anaerobe, only affect PNS (NOT CNS)

Sx: flaccid paralysis that is descending (opposite from Guillon Barre).

Cleaves SNARE protein, but target is motor neurons, ACh (when inhibitted, will cause flacid

In babies, same flaccid paralysis. Likely ingested and lack flora. Usually from honey (spores in honey, not preformed)

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28
Q

Clostridium Difficile (C. Diff)

A

Gram + bacilli, spore forming, obligate anerobe

Nosocomial infection. can be caused by Clindamycin (esp by improper hand washing)

Two exotoxins:

A: binds to brush border of intestine (A for apple) cause wattery diarrhea

B: Depolymerize actin, cause pseudomembrane colitis (B for licorice)

PCR Assay to detect TOXIN, not bacteria in stool

Tx: ORAL vancomycin (NOT IV), metronidazole

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29
Q

Clostridium Perfringens

A

Gram + Bacilli, spore former that can be found in soil, obligate anaerobe

  1. Motorcycle accident
  2. Military accidents (both have large flesh exposed to soil)

Can cause:

  1. Gas Gangrene: gas produced under tissue as organism consumes carbohydrates. Produces α toxin lecithinase (produce a double zone of hemolysis on agar)

Tx: IV PCN G

  1. Food Poisoning: late onset (from ingesting spores), watery diarrhea. Transient, no tx
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30
Q

The 4 Clostridium and what defines them

A
  1. Clostridium Difficile
  2. Clostridium Botulinism
  3. Clostridium Perfringens
  4. Clostridium Tetani

Defined by: Gram-positive, spore-forming, obligate anaerobic bacilli.

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31
Q

Corynebacterium diphtheriae

A

Gram + bacilli,

toxin inhibits Elongation factor 2 to inhibit protein synthesis (inhibiting the translocation step)–> cell death –> Pharyngitis with pseudomembranes (like C-Diff) in throat and severe lymphadenopathy (bull neck)

Plated on Tellurite and Loeffler plates

ELEK test to tell if toxic strain or not (usually immigrant who was not immunized)

Toxoid vaccine routinely administered in US

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32
Q

Listeria monocytonegenes

A

Gram + Bacillus, catalase +, Beta hemolytic

usually associated with infections in pregnent women (20x more likely)

Motile (due to flagella) extracellular, when intracellular polymerizes actin (Actin rocket)

Can survive cold temperatures (contaminate refrigerated items, milk, cheese)

3rd most common cause of meningitis in newborn (after group B strep and E. Colo) as well as adults >60 years old

Tx: ampicillin

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33
Q

Yersinia enterocolitica

A

Cause of pseudoappendicitis characterized by fever, vomiting, diarrhea, and right lower quadrant pain with imaging studies showing a normal appendix (also C. Jejuni is associated with pseudoappendicitis)

  • also associated with erythema nodosum (C. Jejuni is NOT)
  • associated with puppy feces, toddlers affected, transmitted via milk products, rodents are host in US, buboes form on skin, Streptomycin (with tetracycline) for treatment
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34
Q

Name:

2 Gram + Cocci

2 Gram + Rod

2 Gram - Cocci

2 Gram - Rod

…and how to differentiate the Gram + Cocci, and the Gram - Rod

A
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35
Q

Non Gram-staining bacteria (3 reasons)

A
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36
Q

Bacteriostatic vs Bactericidal

A

Bacteriostatic: arrests the growth and replication of bacteria, thus allowing host immune system to complete pathogen elimination. Inhibition of protein synthesis (except aminoglycosides)

Bactericidal: kills bacteria and reduces the total number of organisms. Inhibit cell wall synthesis, interference with DNA function or synthesis

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37
Q

Broad spectrum antibiotics (definition, and abx)

A

Covers Gram + and Gram - bacteria

ALL are Bacteriostatic!

Ex: chloramphenicol, sulfonamides, tetracycline, trimethoprim

  • not really useful with immune compromised pts
  • Can cause superinfections, and growth of fungal infections
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38
Q

most common cause of otitis externa (swimmer’s ear)

A

Pseudomonas aeruginosa, isolated in 38% of cases

peaks between ages 7-12. Found in swimmers or someone who spends a lot of time in water (summer camp)

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39
Q

vancomycin resistance

A

wild type terminus is D-alanyl-D-alanine, to which vancomycin binds. Vancomycin resistance is achieved by an enzyme that switches the terminus to D-alanyl-D-lactate, resulting in the loss of one hydrogen-bonding interaction, and a 1000-fold decrease in affinity. Alters cell wall peptidoglycan

-Found in enterococcus often

40
Q

doxycycline side effects

A

sun sensitivity

discoloration of teeth in children <8 years old

41
Q

Protein synthesis inhibitors abx

A

30S inhibitors
A = Aminoglycosides [bactericidal]

T = Tetracyclines [bacteriostatic]

50S inhibitors

C = Chloramphenicol, Clindamycin [bacteriostatic]

E = Erythromycin (macrolides) [bacteriostatic]

L = Linezolid [variable]

“Buy AT 30, CCEL (sell) at 50.

42
Q

Parvovirus

A

“part-of-a- virus” (parvovirus) is ssDNA.

B19 virus—aplastic crises in sickle cell disease, “slapped cheeks” rash in children (erythema infectiosum, or fth disease)

RBC destruction in fetus leads to hydrops fetalis and death, in adults leads to pure RBC aplasia and rheumatoid arthritis–like symptoms

43
Q

Gram + vs. Gram -

A

Gram +: teichoic acid, thick peptidoglycan layer, stain purple on gram stain, single membrane, produce exotoxins primarily

Gram -: endotoxin/LPS, double membrane, thin layer of peptidoglycan, outer membrane, stain red/pink

44
Q

Bugs that do NOT gram stain well

A

These Microbes May Lack Real Color

Treponema

Mycobacteria

Mycoplasma

Legionella

Rickettsia

Chlamydia

45
Q

Periodic Acid-schiff stain (PAS)

A

stains glycogen, used to diagnose Whipple Disease

“PaSs the sugar”

Whipple Disease: foamy macrophages in intestinal lamina propria, mesenteric nodes. Cardiac symptoms, Arthralgias, and Neurologic symptoms are common. Most often occurs in older men.

46
Q

Common bugs that show up on these stains

  1. PAS stain
  2. Ziehl-Neelsen Stain
  3. India Ink Stain
  4. Silver Stain
A
  1. PAS stain: Tropheryma Whipplei
  2. Ziehl-Neelsen Stain: Acid fast bacteria (mycobacteria), Nocardia, protozoa
  3. India Ink Stain: Cryptococcus neoformans
  4. Silver Stain: Fungi, Legionella, H. Pylori
47
Q

MacConkey agar

A

Lactose-fermenting enterics. Fermentation produces acid, causes colonies to turn pink

ex: Klebsiella, E.Coli, Enterbacter and Serratia (weak)

MacConKEE’S

48
Q

Actinomyces vs Nocardia

A

Both are gram + branching filamentous rods (Nocardia is weakly acid fast)

Nocardia is aerobic, catalase and urease +, treat with sulfonuria

Actinomyces is anaerobic, treat with PCN G

49
Q

alpha hemolytic bacteria

A

Partial reduction of hemoglobin causes greenish or brownish color without clearing around growth on blood agar

  • Strep pneumonia
  • Viridans Streptococci
50
Q

beta hemolyic bacteria

A

Complete lysis of RBC. Clear area surrounding colony on blood agar

  • S. Aureus
  • Strep Pyrogens (GAS)
  • Strep Agalactiae (GBS)
  • Listeria
51
Q

Neisseria Meningococci

A

Easily spread in college dorms (has 15% mortality)

  • Has polysaccharide capsule, ferments maltose.
  • There is a vaccine but NO type B (most commonly infected with type B)
  • Resiratory/oral secretions

Presentation: petechial hemorrhages, Waterhouse Friderichsen syndrome (adrenal insufficiency), fever, DIC, shock

Tx: Ceftriaxone, Rifampin for prophylaxis in close contacts

52
Q

Waterhouse-Friderichsen Syndrome

A

Seen in Neisseria Meningocci

-Hemorrhagic adrenalitis or fulminant meningococcemia is defined as adrenal gland failure due to bleeding into the adrenal glands

53
Q

Neisseria Gonococci

A

Gram - Dipplococci

NO polysaccharide capsule

NO maltose metabolism

NO vaccine

Can cause gonorrhea, septic arthritis (unilateral), PID (white purulent discharge), Fitz Hugh Curtic Syndrome (spreads to peritoneum), violin string adhesions to capsule of liver

  • cause neonatal blindness that happens immediately
  • hangs out in PMNs

Tx: Ceftriaxone (add in azithromycin or doxycycline for possible concurrent Chlamydial infection

54
Q

Haemophilus Influenzae

A

Small gram - coccobacillary (hybrid) rod.

  • Aerosol transmission
  • Culture on Chocolate agar (which contains factor V (NAD+) and X (hematin)

Presentation: HaEMOPhilis: Epiglottitis (cherry red, drooling child), Meningitis (capsular form, Type B), Otitis media, Pneumonia

Tx: Amox/clav for mucosal, Ceftriaxone for meningitis

Rifampin prophylaxis for close contacts

55
Q

Legionella Pneumophilia

A

Gram - Rod…but gram stains poorly. Seem on Silver Stain.

  • Grows on charcoal yeast extract medium with iron and cysteine
  • Labs may show hyponatremia <130

Concerning for Legionnaire’s Disease and Pontiac Fever

tx: macrolide or quinolone

56
Q

Legionnaires’ Disease and Pontiac Fever

A

Legionnaires’ Disease: severe pneumonia (unilateral), fever (>104), GI (diarrhea), CNS symptoms (HA, confusion). Common in smokers and in chronic lung disease

Often arises from air conditioning sysyems, hot water tanks

Pontiac Fever: flu-like syndrome that is self limiting

57
Q

Pseudomonas Aeruginosa

A

Gram - Rod, motile. Oxidase +, Obligate anaerobe.

  • Produces pyocyanin (blue-green pigment), has grape-like odor.
  • Produces endotoxin (fever, shock), and exotoxin A (inactivates EF-2)

Associated with: Pneumonia (#1 cause), Ecthyma gangrenosum, UTI, Diabetes/IV drug use, Osteomyelitis, Otitis EXTERNA, Hot tub folliculitis

Tx: Aminoglycosides, Fluoroquinolones, Extended spectrum PCN (piperacillin)

58
Q

Ecthyma gangrenosum

A

Rapidly progressive, necrotic cutaneous lesion caused by Pseudomonas bacteremia. Typically seen in immunocompromised patients

59
Q

4 strains of E. Coli (and some fun facts about each)

A
  1. EIEC: microbe Invades Intestinal mucosa
  2. ETEC: travelers diarrhea. Watery. from poor water (Montezuma Revenge)
  3. EPEC: no toxin produced, diarrhea in pediatrics
  4. EHEC: hemorrhagic diarrhea, from undercooked hamburgers. associated O157:H7. Can cause Hemolytic Uremic Syndrome (shiga-like toxin, damages 60S subunit). does NOT ferment sorbitol (defining feature from others)
60
Q

Klebsiella

A

Gram - Rod. Intestinal flora that causes lobar pneumonia in alcoholics and diabetics. Ferment lactose, Urease +

Alcoholics

Aspiration pneumonia

Abscess in lung and liver

diAbetics

-Dark red “current jelly” sputum. Also causes nosocomial UTI’s that are often MDR.

61
Q

Helicobacter Pylori

A

Gram - Rod, curved, terminally flagellated

TRIPLE +/TRIPLE therapy

Catalase +, Oxidase +, Urease +

Amoxicillin, Clarithromycin, PPI (Abx Cure Pylori)

-urease produces ammonia which creates alkaline environment which helps it survive acididc mucosa in stomach

95% duodenal ulcers caused H. Pylori, can progress to adenocarcinoma and MALT lymphoma

62
Q

Lyme Disease (bacteria and stages)

A

Borellia Burgdoferi-a spirochete, spiral shaped bacteria that does not gram stain well. Visualized wit aniline dyes (Wright or Giemsa stain)

Ixodes deer tick is vector, mouse is reservoir, and white tailed dear is obligatory host.

usually confined to Northeast USA

Stage 1. erythema migrans (bulls eye rash), flu-like sx

Stage 2: myocarditis, Bilateral Bells Palsy (CN VII)

Stage 3: encephalopathy, arthritis (can migrate)

Tx: Doxycycline if early, Ceftriaxone if later, more severe

63
Q

Leptospira interrogans

A

Spirochete (spiral shaped bacteria with axial filaments)

Found in water contaminated with animal urine. Prevelent in tropics, esp Hawaii.

Causes Leptospirosis: flu-like symptoms, myalgias (calves classically), conjunctival suffusion (erythema without exudate),

Cause Weil Disease: severe form with jaundice, and azotemia from liver and kidney dysfunction.

64
Q

Syphilis overview

A

Caused by Spirochete Treponema Pallidum

  • Visualized by dark field microscopy or direct flourescent antibody (DFA)
  • Can do RPR or VLDR (although has false negatives with SLE, MONO, RF, Leprocy, IV drugs)
  • Primary
  • Secondary
  • Tertiary
  • Congenital

Tx: ALL WITH PCN!!!!

65
Q

Primary Syphilis

A

Painless Chancre.

Localized disease.

VLDR + 80% in this stage.

If not treated in 3-6 weeks, will progress to secondary

66
Q

Secondary Syphilis

A
  • Secondary=Systemic
  • Maculopapular Rash (including palms and soles)
  • Condylomata lata (smooth, moist, wart-like white lesions on genitals)
  • VDRL/RPR nonspecific. Use FTA-ABS test
67
Q

Tertiary Syphilis

A

Gummas (chronic granulomas)

Aortitis (vasa vasorum destruction)

Neurosyphilis (tabes dorsalis, general paresis)

Argyll Robertson pupil (constricts with accomodation but is not reactive to light) = prostitute pupil

68
Q

Congenital Syphilis

A
  • Facial abnormalities such as rhagades (linear scars at angle of mouth)
  • Snuffles
  • Saddle nose
  • Notched Hutchinson teeth (notched incisors)
  • Mulberry molars
  • Short maxilla
  • Saber shins
  • CN VIII deafness
69
Q

Jarisch-Herxheimer reaction

A
  • Seen in syphilis patients several hours after abx are started. Flu-like syndrome (fever, chills, myalgia)
  • Due to killed bacteria (usually spirochetes) releasing toxins
70
Q

Leprosy (Hansen Disease)

A
  • Caused by Mycobacterium Leprae, an acid-fast bacillus that likes cool temperatures.
  • Reservoir is ARMADILLO

2 forms:

  1. Lepromateous: L=lethal. Th2 response. Leonine (lion-like) facies. Highly communicable.
  2. Tuberculoid: hairless skin plaques. Th1 immune response.

Tx: Tuberculoid: dapsone and rifampin (6 months)

Lepromateous: dapsone, rifampin, clofazimine (2-5 years)

71
Q

VDRL (Venerial Disease Research Laboratory) false positives

-usually positive in what disease??

A

Usually positive in Syphilis, along with RPR

-False positive in VDRL

V: Viral infection (EBV, hepatitis)

D: Drugs (IV drug use)

R: Rheumatic Fever

L: Leprosy and Lupus

72
Q

Red Man Syndrome

A

Caused by Vancomycin due to a secondary realease of histamine

-Can be avoided by slow injection (over 1-2 hours)

73
Q

Mechanism of resistance of Cephalosporins

A

Alteration of Penicillin Binding Protein (PBP) and through expelling B-lactams with cell membrane efflux pumps

74
Q

Most common cause of pneumonia in CF pt and what is the treatment? (esp pts under 21 years old)

A

Pseudamonas and treatment is Gentamycin

75
Q

Cat Scratch Disease causing bacteria

A

Bartonella Henselae a gram - bacteria closely related to Rickettsia

-appear as darkly staining bacilli on Warthin-Starry stain, a silver nitrate based stain

76
Q

Chancroid

A

Painful genital ulcer with exudate, inguinal adenopathy

Haemophilus ducreyi (it’s so painful, you “do cry”)

30% of people also present with painful inguinal lymph nodes

Gram - coccobacillus

77
Q
A
78
Q

use of macrolides clinically

A

-Atypical pneumonias (Mycoplasma, Chlamydia, Legionella), STIs (Chlamydia), gram-positive cocci (streptococcal infections in patients allergic to penicillin), and B. pertussis.

79
Q

Neisseria overview

A
  • Gram - Dipplococci (synonymous with Neisseria)
  • Unable to grow on blood agar
  • Can be grown on headed blood agar called Chocolate Agar
  • VPN agar (polymycin, vancomycin, nistatin)
  • Thayer Martin agar = VPN agar
  • C5-C9 deficiency are more susceptible to Neisseria
  • Pillus is big virulence factor. Antigenic variation (why so good at evading)
  • IgA protease
80
Q

Endotoxin vs Exotoxin

A

Endotoxin: LPS found in outer membrane of gram - bacteria (both cocci and rods). Composed of O antigen + core polysaccharide + Lipid A (the toxic component**). Released upon lysis or by living cells in bleds. Ex: Meningococcemia, sepsis by gram - rods

Exotoxin: Actively released by certain species of gram + and gram - bacteria. Highly fatal at low doses. Toxoids used as vaccines. Ex: Tetanus, botulism, diptheria

81
Q

Some examples of bugs with exotoxins and basic mechanism (13)

A

1. Cornybacterium diptheriae: Inactive EF-2

2. Pseudamonas aeruginosa: Inactive EF-2

3. Shigella: Inactivate 60S ribosome by removing adenine

4. EHEC: Inactivate 60S ribosome by removing adenine

5. ETEC: Heat labile, increase cAMP. Heat stable, increase cGMP

6. Bacillus anthracis: Mimic AC to increase cAMP

7. Vibrio Cholerae: overactivate AC to increase cAMP

8. Bordetella Pertussis: disable Gi, overactivate AC, increase cAMP

9. Clostridium Tetani/Botulinism: cleave SNARE

10. Clostridium Perfringens: alpha toxin phospholipase (lecithinase) that degrades tissue and cell membranes

11. Strep Pyogens: Steptolysin O, degrades cell membrane

12. S. Aureus: TSST, bind MHC II and TCR cause release of IL-1, IL-2, IFN-y, TNF-a –> shock

13. Strep pyogens: Exotoxin A, bind MHC II and TCR cause release of IL-1, IL-2, IFN-y, TNF-a –> shock

82
Q

TORCHES infections. What are they and what do they cause?

A

Infectious agents that can cross placenta and cause congenital infections to fetus

ToRCHeS

  • *T**oxoplasmosis
  • *R**ubella
  • *C**MV
  • *H**IV
  • *H**erpes virus
  • *S**yphilis
83
Q

Norovirus

A

-Caliciviruses + ssRNA, Icosahedral, non-enveloped, fecal-oral transmission

MAJOR cause of viral gastroenteritis. Often seen on cruise ships, can be caused by shellfish

-Cause watery diarrhea, N/V

84
Q

EBV is strongely associated with what types of Hodgkins Lymphoma (2)

A
  1. Mixed (also has the most Reed Sternberg cells)
  2. Lymphocyte Poor
85
Q

Penicillinase-sensitive penicillins are what 3 abx and cover what bugs

A

-Amoxicillin, Ampicillin, Aminopenicillin

These are Animopenicillins that have wide spectrum.

“HHELPSS”

H. Pylori

H. Infleunza

E. Coli

Listeria monocytogenes

Proteus mirabilis

Salmonella

Shigella

86
Q

Drug given prior to surgery to prevent S. Aureus wound infections

Drug given prior to ABDOMINAL surgery

A

Cefazolin (ancef), a first generation cephalosporin given prior to non-abd surgery

A subset of the second generation cephalosporins is the cephamycin group (cefoxitin). Cephamycins are used for their activity against gram-negative gut anaerobes (usually given before abdominal surgery),

B. fragilis

E. coli

Klebsiella

Proteus

87
Q

Uses of Ceftriaxone (3 main ones)

A
  • Meningitis, gonorrhea, disseminiated Lyme disease, Pseudomonas aeruginosa (ceftazidime only)
  • Important to note that 3rd generation cephalosporins can cross the CNS (reason why can treat meningitis)
88
Q

General rule concerning coverage of Cephalosporins as increase in generations and what are the organisms NOT covered by cephalosporins?

A

-There are 5 different generations of cephalosporins with varying properties and coverage. As a general rule, progressive generations migrate from gram-positive to gram-negative coverage.

Organisms typically not covered by cephalosporins can be remembered by the mnemonic LAME

Listeria

Atypicals (Chlamydia, Mycoplasma)

MRSA (ceftaroline is the exception)

Enterococci

89
Q

What bacteria colonizes the female vaginal tract and causes neonatal meningitis

A

Group B Strep (Streptococcus agalactiae)

90
Q

What bug and what stain and what tx?

A

Cryptococcus Neoformans. India ink (clear halo). Tx with Amphotericin B

91
Q

Alcoholic pt aspirates food –> pneumonia. What types of pneumonia are most common and what is the common tx?

A
  • Anaerobics (Bacteroides, Fusobacterium, Peptostreptococcus) or S. Aureus.
  • Most often found in R lung. Location depends on position during aspiration

Upright: basal segment R lung

Supine: posterior segment of right upper lobe or superior sebment of right lower lobe

Tx: Clindamycin

92
Q

Mechanism of spread of Rabies?

A

-commonly found in Purkinje cells of cerebellum and in hippocampal neurons. Rabies has long incubation period (weeks to months) before symptom onset. Postexposure prophylaxis is wound cleaning plus immunization with killed vaccine and rabies immunoglobulin. Example of passive-active immunity.

Travels to the CNS by migrating in a retrograde fashion up nerve axons after binding to ACh receptors.

93
Q

Pasteurella multocida

A

Gram - Bacilli (zoonotic bacteria)

  • Lives in oropharynx of cats and dogs, often transmitted by bites.
  • Catalase +, Oxidase +, Grown 5% sheeps blood agar
  • Cause of osteomyelitis and cellulitis (<24 hours)

Demonstrates double staining (safety pin)

Tx: PCN

94
Q

Bartonella Henselae

A

Cause of Cat Scratch Fever

Gram -, stained with Warthyn Starry Stain (SIlver)

  • Can cause lymphadenitis (axillary), can occur in healthy people
  • Also causes bacillary angiomatosis (raised red vascular lesions all over skin). Affects immunocompromised pts (HIV) (looks like kaposi sarcoma)

Tx: Doxycycline for bacillary angiomatosis

Bartonella usually self limiting, can use macrolides

95
Q

Proteus Mirabilis

A

-Gram - Bacilli

Motility causes swarming on agar.

Urease +

Associated with struvite stones (ammonia, magnesium, phosophate), UTI

Staghorn Calculus

Tx: Sulfonamides

96
Q

Coxiella Burnetii

A

Gram - Zoonotic bacteria that causes Q fever.

  • Acquired through aerosols of cattle/sheep feces (via spores)
  • NO rash.
  • Obligate intracellular that resides within phagolysosomes (ONLY ONE TO LIVE IN THIS HOSTILE ENVIRONMENT)
97
Q

Adenovirus

A

DS linear DNA virus that is not enveloped

-Most common cause of tonsilitis. Can cause pneumonia and conjunctivitis “pink eye”

Can cause hemorrhagic cystitis

Found in public swimming pools, children, military recruits

Fecal/oral, respitatory droplet transmission

Serotype 40,41 can cause gastroenteritis

STEP COPY (36 decks)

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