Microbiology and Parasitology Flashcards
What is deficient in ataxia telangiectasia?
IgA
What is the treatment of Di George syndrome?
Transplant of fetal thymus
How do you differentiate Scalded Skin Syndrome (Ritter’s Disease) from TEN (Lyell Disease)?
Separation occurs at STRATUM GRANULOSUM in Ritters disease vs. separation at DERMO EPIDERMAL JUNCTION at Lyell Disease
What 3 diseases present with a strawberry tongue?
Toxic shock syndrome, Kawasaki disease, Scarlet fever
What is the DOC for VRSA?
Linezolid
What is the 2nd most common cause of UTI in sexually active women?
Staph saprophyticus
Most common bacterial cause of sore throat?
Strep pyogenes (group A beta hemolytic streptococci)
What facilitates cellulitis caused by Strep pyogenes?
Hyaluronidase (spreading factor)
Rash begins in the trunk then spreads to the extremities but spares the face
Scarlet fever
What test is used to determine a patient’s susceptibility to scarlet fever?
Dick test
Most common cause of neonatal pneumonia, sepsis and meningitis
Strep agalactiae (GBS)
Differentiate Strep pyogenes from Strep agalactiae
B - BRAS: gBs Resistant, gAs Sensitive
Gram positive “lancet-shaped” cocci in pairs or short chains
Strep pneumoniae
What bacteria is sensitive to optochin and exhibits a (+) Quellung reaction?
Strep pneumoniae
Most common cause of subacute endocarditis?
viridans Streptococci (S. sanguis)
Aerobic, gram (+) box car like rods, spore forming
Bacillus anthracis
DOC for cutaneous anthrax
Ciprofloxacin
The capsule of Bacillus anthracis is unique, what is it made of?
poly-D-glutamic acid
What gram (+) bacteria causes ophthalmitis described as no light perception within 48hrs of traumatic eye injury?
Bacillus cereus
What is the DOC for Bacillus cereus?
None. Symptomatic treatment only. (Tricky!!)
What anaerobic gram (+) bacteria looks like a tennis racket?
Clostridium tetani. Due to the presence of a terminal spore
What are the most common immunologic types of C. botulinum in humans?
Types A, B and E
What makes up the triad of Botulism?
Symmetric descending paralysis, absence of fever, and intact sensorium
Anaerobic, gram (+), non motile bacteria that grows on egg yolk agar
Clostridium perfringens
What toxin is involved in Gas Gangrene?
Alpha toxin - Clostridium perfringens
Gram (+) bacteria that exhibits double hemolysis on blood agar
Clostridium perfringens
What is the most common cause of antibiotic associated diarrhea?
Clindamycin
Non-motile, gram (+) club/comma shaped rods arranged in a V or L shape that looks like chinese characters
Corynebacterium diphtheriae
What test do you use to detect toxigenicity of Corynebacterium diphtheriae?
Modified Elek test
Metachromatic granules of Corynebacterium diphtheriae
Babes-ernst granules or Volutin granules
Where do you culture Corynebacterium diphtheriae?
Tellurite plate
Gram (-), kidney bean diplococci with an insignificant capsule
Neisseria gonorrhea
Gram (-) diplococci that ferments maltose and glucose
Neisseria meningitidis
Classic medium for culture of Neisseria meningitidis
Thayer - Martin VCN media
Most severe form of meningococcemia that results to adrenal insufficiency
Waterhouse - Friderichsen Syndrome
What do you call the rash in meningococcemia?
Purpura fulminans
DOC for Neisseria gonorrhea
Ceftriaxone + Doxycycline
Perihepatitis associated with gonorrhea
Fitz - Hugh - Curtis Syndrome
What is the most common cause of epiglottitis?
H. Influenzae
Most common cause of COPD exacerbations?
H. Influenzae
2nd most common cause of otitis media
Non - typable H. Influenzae
Most common cause of septic arthritis in infants
H. Influenzae
Where do you culture Bordetella pertussis?
Bordet - Gengou agar or Regan Lowe charcoal medium
What toxin causes whooping in B. Pertussis infection?
Tracheal cytotoxin
What organism causes Pontiac Fever? Described as a mild flu-like illness
Legionella pneumoniae
What E. coli toxin causes bloody diarrhea?
Verotoxin (shiga-like)
What causes traveler’s diarrhea or Montezuma’s Revenge?
Enterotoxigenic E. Coli
What teat detects Salmonella antibodies in the patient’s serum?
Widal Tests
What causes Salmonella setpticemia?
Salmonella choleraesuid
Where does the chronic carrier state of Salmonella typhi occur?
Gallbladder - treated with Ampicillin or cholecystectomy
Where is Shigella and Salmonella cultured?
XLD (xylosine lysine deoxycholate) medium
Gram (-), non-lactose fermenting rod, non-motile. Humans are its only host.
Shigella
Most common cause of bacillary dysentery
Group D: Shigella sonnei - Duval’s bacillus
Most severe form of bacillus dysentery. Also the most common cause of epidemic dysentery.
Group A: Shigella dysenteriae type 1 - Shiga bacillus
Bacteria found in contaminated raw seafood and among shellfish handlers
V. parahaemolyticus and V. vulnificus
True or False: Shigella has a low infectious dose making it highly virulent
True
What is the toxin released by cholera?
Choleragen
What is the culture medium of cholera?
TCBS (thiosulfate citrate bile salts) agar
Short term immunity with the cholera vaccine may cause?
Herd immunity
Comma shaped, gram (-) rod that grows well on Skirrow’s agar
Campylobacter jejuni
True or false: V. Cholera is the most common cause of bacterial gastroenteritis
False - most common is Campylobacter jejuni
What are the 2 disease associations of Campylobacter jejuni infection?
Guillain-Barre Syndrome and Reiter’s Syndrome
Triad of Reiter’s Syndrome
Urethritis, Uveitis, and Arthritis
H. Pylori is the most common cause of?
Duodenal ulcers
What organism is associated with “currant jelly sputum”?
Klebsiella pneumoniae - necrotizing pneumonia
What are struvite stones made of and what organism is this associated with?
Magnesium ammonium phosphate, Proteus mirabilis
What is the medium used to culture Pseudomonas aureginosa?
Cetrimide agar
Gram (-) rod, obligate aerobe, non-lactose fermenting which gives a green-blue stain on wound dressings
Pseudomonas aureginosa
Organism responsible for malignant otitis externa among diabetics
Pseudomonas aureginosa
Predominant anaerobe of the human colon
Bacteroides fragilis
Only 2nd gen cephalosporin with good anaerobic coverage. Used to treat Bacteroides fragilis infections.
Cefoxitin
What is the treatment for undulating fever?
Brucella abortus (Brucellosis) - doxycycline plus rifampicin
Gram (-) rod with bipolar (safety pin) staining
Yersenia pestis
Assay used to determine drug resistance for Mycobacterium tuberculosis
Luciferase assay
Most important virulence factor in TB
Cord factor
Radiologically detectable calcification in TB
Ranke’s complex
Differentiate primary complex TB from reactivation TB
Primary - middle or lower lobes. Reactivation - apices.
Culture medium of M. Leprae
Mouse footpads, armadillo
Most common presentation of TB in adults? In children?
Adults - cough. Children - weight loss.
DOC for acute flare-ups of Lepromatous Leprosy
Erythema nodosum leprosum - Thalidomide
Medium for the smallest free living organism
Eaton’s culture - Mycoplasma pneumoniae
Most common infectious cause of Stevens-Johnson syndrome
Mycoplasma pneumoniae (walking pneumoniae)
Gram (+), beaded, filamentous anaerobic organism that grows as normal flora in the mouth
Actinomyces israelii
Fite-Faraco stain can be used on what 2 organisms?
M. Leprae and Nocardia asteroides
Tiny gram (-) bacteria that look like corkscrews
Spirochetes
Specialized flagella of spirochetes that run sideways along the organism under the outer membrane sheath
Periplasmic flagella
Cause of death of congenital syphylis
Pulmonary hemorrhage
What is the Hutchinson Triad seen in congenital syphylis?
Hutchinson teeth, deafness, keratitis
Pupils that accommodate but do not react seen in Tertiary Syphylis
Argyll Robertson pupils or Prostitute’s Pupil
What is the screening test for syphylis?
RPR-VDRL
Confirmatory test for Syphylis
FTA-ABS
Diagnostic lesion in secondary Syphylis
Condyloma lata
Influenza-like symptoms few hours after receiving penicillin
Jarisch - Herxheimer Reaction
Organism responsible for a firm, ulcerated painless lesion with a punched out base and rolled edges
Treponema pallidum, chancre of primary syphylis
What 2 bacteria exhibit a CSF analysis with lymphocytic predominance?
Treponema pallidum, Mycobacterium tuberculosis
DOC for Treponema pallidum infection
Syphilis - Benzathine penicillin G
Largest medically important bacteria
Borrelia burgdorferi
Lyme disease is caused by a bite from?
Deer tick (Ixodes scapularis)
DOC for Borrelia burgdorferi infection
Lyme Disease - Doxycycline
Pathognomonic lesion for Borrelia burgdorferi infection
Lyme disease - erythema chronicum migrans
DOC for Relapsing Fever
Borrelia recurrentis - Doxycyline or erythromycin
Transmission of relapsing fever is through?
Human body louse - Pediculus humanus
Obligate aerobe with a Shepherd’s crook appearance. In what medium does it grow?
Leptospira interrogans - EMJH or Fletcher’s Medium
Gold standard in diagnosing Leptospirosis
Leptospire Microscopic Agglutination Test (MAT)