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Flashcards in Infectious Disease - Specific Findings Deck (63):
1

Staphylococcus aureus (S. aureus)

Gram positive cocci arranged in clusters

Catalase positive - increased susceptibility in granulomatous disease

Coagulase positive - coagulase cleaves fibrinogen to fibrin causing clotting and formation of fibrin clot around infection leading to abscess thayer

2

Red Man Syndrome

Drug reaction to rapid infusion of Vancomycin mediated by non-specific degranulation of mast cells; characterized by diffuse flushing / erythematous rash of the face, neck, and upper torso

Prevented with slower infusion and pre-treatment with anti-histamines

3

Thayer-Martin agar

AKA VPN Media

Chocolate agar plate suffused with vancomycin (inhibits gram positive organisms), polymixin (inhibits gram negative organisms except for Neisseria), and nystatin (inhibits fungi); suppresses the growth of endogenous flora while supporting growth of N. gonorrhoeae

Gold standard for diagnosis of Neisseria gonorrhoeae

4

Lowenstein-Jensen agar

Used to culture mycobacterium tuberculosis

Selects against gram positive bacteria in respiratory flora

5

MacConkey agar

Used to culture lactose-fermenting enteric bacter (E. coli, Klebsiella) commonly found in UTIs

6

Bordet-Gengou (Potato) agar

Used to culture Bordetella Pertussis

7

Erythema migrans

Red bullseye rash, specific for early phase of Lyme disease

8

Roth spots

Round, white spots on the retina, surrounded by hemorrhage

Associated w/ bacterial endocarditis

9

Janeway lesions

Small, painless, erythematous lesions on palms or soles

Associated with bacterial endocarditis

10

Thumbprint sign

Thickening of the epiglottis and aryepiglottic folds

Associated with epiglottitis, often caused by H. flu

11

UTI - Urine Labs

+ Leukocyte Esterase (Bacterial)
+ Nitrites (Gram negative)
+ Urease (Klebsiella, Proteus)
- Urease (E. coli, enterobacter)

12

Morulae

"Berry-like" cytoplasmic inclusions in macrophages / neutrophils

Associated with Erlichosis (Erlichia Chaffeensis infection)

13

Charcoal yeast extract agar

Gold standard for growth of Legionella (i.e. respiratory legionellosis / Legionnaire's disease)

14

Strawberry cervix

Associated with trichomonas vaginalis

15

Pneumonia in neonates (< 4 weeks) - Common pathogens

Group B. Strep
E. coli

16

Pneumonia in children - Common pathogens

Viruses (RSV)
Mycoplasma
C. trachomatis (infants - 3 years)
C. pneumoniae (school-aged children)
S. pneumoniae

17

Pneumonia in adults (18-40, 40-65)) - Common pathogens

Mycoplasma
C. pneumoniae
S. pneumoniae

+ in older adults (40-65)
H. influenzae
Anaerobes
Viruses

18

Pneumonia in the elderly - Common pathogens

S. pneumoniae
Influenza virus
Anaerobes
H. influenzae
Gram negative rods

19

Black colonies on cystine-tellurite agar

Corynebacterium diptheria (gram positive rod)

20

HBsAg / anti-HBsAg

HBsAg = HBV surface antigen; indicates active HBV infection

Anti-HBsAg indicates immunity to HBV

21

HBcAg

HBcAg = HBV core antigen

Anti-HbcAg (IgM) = acute / recent infection

Anti-HbcAg (IgG) = prior / chronic infection

22

HbeAg

HBeAg = HBV core antigen which is a marker of active viral replication / high transmissability

anti-HbEAg - indicates low transmissability

23

CSF findings in Polio

Elevated WBCs, slightly elevated protein
Normal glucose

24

Histologic findings in chlamydia conjunctivitis

Epithelial cells of the conjunctival lining show basophilic intracytoplasmic inclusions, which are representative of the organism C. trachomatis itself

25

"Violin string" adhesions

Adhesions between the liver capsule and the peritoneum

Seen in "Fitz-Hugh-Curtis" syndrome - infection of the liver capsule by C. trachomatis or N. gonorrhea secondary to pelvic inflammatory disease

26

Common causes of meningitis - Newborn (0-6 months)

Group B streptococci
E. coli
Listeria

27

Common causes of meningitis - Children (6 months - 6 years)

S. pneumoniae
N. meningitidis
H. influenza
Enteroviruses (esp. Coxsackievirus)

28

Common causes of meningitis in adolescents and adults (6 - 60 years)

S. pneumonia
N. meningitidis (#1 in teens)
Enteroviruses
HSV-2

29

Common causes of meningitis in the elderly (60+)

S. pneumoniae
Gram negative rods
Listeria

30

Viral causes of meningitis

Enteroviruses (esp. Coxsackievirus)
HSV-2
HIV
West Nile Virus
VZV

31

Pulmonary Aspergillosis - CT and culture findings

CT shows "air crescent sign" - represents the presence of air between Aspergillus-infected and normal tissue

Culture shows 45-degree branching septated hyphae with rare fruiting bodies

32

Most common cause of osteomyelitis - in general?

S. aureus

33

Most common cause of osteomyelitis - in IDUs and diabetics?

Pseudomonas
Serratia

34

Most common cause of osteomyelitis - in Sickle Cell Anemia?

Salmonella

35

Most common cause of osteomyelitis with vertebral involvement (Pott's Disease)?

Mycobacterium tuberculosis

36

Most common cause of osteomyelitis with prosthetic joint involvement?

S. aureus
S. epidermidis

37

Most common cause of osteomyelitis in sexually active adults?

N. gonorrhea

38

Koplik Spots

Blue/white lesions of the buccal mucosa

Seen in primary measles infection

39

Cowdry A Inclusion Bodies

Seen in biopsies of Varicella Zoster (Shingles) lesions

Appear as intranuclear, eosinophilic inclusions surrounded by a clear halo

40

Bordatella Pertusis - Culture requirements

Bordet-Gengou (potato) agar

41

Bacterial meningitis - Most common organisms in young adults (2)

Strep pneumo
N. meningiditis

42

Red pigment observed in UTI culture - what's the pathogen?

Serratia - gram negative bacillus commonly causing nosocomial UTI

43

Clue Cells

Vaginal epithelial cells coated in bacteria (Gardenella vaginalis)

Classic microscopic finding of bacterial vaginosis

44

Bacterial pneumonia occurring secondary to influenza - most common pathogens? (3)

Streptococcus pneumoniae
Staphylococcus aureus
H. influenzae

45

Neonatal conjunctivitis - how to differentiate 2 common causes?

Presents as inflammation, swelling around the eyelids, and purulent yellow discharge

Chlamydia trachomatis - sx begin 5-14 days after birth

Neisseria gonorrhoeae - sx present 2-5 days after birth

46

CMV Retinitis

Presents with rapidly diminishing sight - loss of central vision with floaters and blind spots

Fundoscopic exam demonstratates necrotizing retinitis, perivascular hemorrhages, and retinal detachment

47

Maculopapular rash on the palms & soles - Associated diseases

Secondary syphilis
Cocksackie A virus
Rocky Mountain Spotted Fever

48

Which bacterial exotoxins work by ADP-ribosylation of EF-2?

Diptheria

Pseudomonas

49

What is the mechanism of Shiga toxin, and in which diseases is it seen?

Shiga toxin inactivates ribosomes, leading to inhibition of protein synthesis and cell death

Causes hemolytic uremic syndrome including renal failure, microangiopathic hemolytic anemia, DIC, thrombocytopenia

Seen in Shigella infection and Enterohemorrhagic E. coli (EHEC)

50

"Slapped cheeks"

AKA erythema infectiosum - blanchable erythema on the cheeks with perioral pallor

Seen in "Fifth Disease" caused by Parvovirus B19; rash appears after fever has resolved

51

"Strawberry tongue"

Scarlet fever
Kawasaki Disease
Toxic Shock Syndrome

52

Flavivirus

Enveloped, positive sense, single-stranded RNA virus

HCV
Yellow Fever
Dengue
St. Louis encephalitis
West Nile Virus

Part of the Arbovirus classification (except HCV)

53

Filoviruses

Enveloped, negative-sense, single stranded RNA Virus

Ebola
Marburg

54

Paramyxoviruses

Enveloped, negative-sense, single stranded RNA Viruses

Parainfluenza
RSV
Measles
Mumps

55

Rhabdoviruses

Enveloped, single stranded, negative sense RNA virus

Rabies

56

Picornaviruses

Non-enveloped, single-stranded, positive-sense RNA virus

Rhinovirus
Poliovirus

57

Coronaviruses

Enveloped, single-stranded, positive-sense RNA Viruses

SARS
MERS

58

Orthomyxoviruses

Enveloped, negative-sense, single stranded RNA virus genome in 8 segments

Influenza

59

Bunyavirus

Enveloped, negative-sense, single-stranded RNA virus

California encephalitis
Hantavirus

60

Romana Sign

Unilateral periorbital swelling

Characteristic of the acute phase of Chagas Disease

61

Urease positive organisms

Staphylococcus
Ureaplasma
Proteus
Klebsiella
Pseudomonas

62

Is candida germ tube positive or germ tube negative?

Germ tube positive

63

Special stain for identification of Bartonella henslae

Warthrin-Starry stain shows gram-negative proteobacterium