Board Prep Micro Flashcards
Clostridium perfringes toxin
alpha toxin with gas gangrene
this virulence factor contains lecithinase and phospholipase c
causing the lysis of phospholipids
Lysogenic transduction
the viral genome enters the of bacterium A. When the bacterium replicates some of the DNA is incorporated into the bacteriophage and can affect Bacterium B
cholera toxin and diphtheria toxin
Sudden onset fever followed days later by a rash that spreads in a peripheral to central pattern
Rocky Mountain spotted fever (Rickettsia rickettsii)
Weil-Felix test is classic diagnoistic test: based on cross-reactivity btwn Rickettsia and certain serotypes of Proteus
The Somatic O antigen is capable of cross-reacting with anti-Rickettsia antibodies causing agglutination
Necrotizing fasciitis
rapidly evolving infection of the fascia. The M protein allows bacteria to evade phagocytosis and move rapidly through tissue
BCG vaccination
clear chest radiograph should not be treated for TB if a PPD yields response of less than 10 mm
Black non healing eschar and surrounding edema
Cutaneous Anthrax (B. anthracis, sport forming gram-positive rod) Anthrax edema toxin is an adenylate cyclase that increases intracellular cAMP
Bordetella pertussis toxin MOA
activated adenylate cyclase
Clostridium botulinum Toxin MOA
inhibits the release of acetylcholine at synaptic vesicles
C. Diphtheriae (and Pseudomonas aeruginosa) toxin MOA
ADP-ribosylation of EF-2
Clostridium tetani toxin MOA
Inhibits the release of GABA and glycine (inhibitory neurotransmitters)
Shigella dysenteriae, E. Coli O157:H7 toxin MOA
Inhibits protein synthesis by degrading ribosome subunit 60S
S. Aureus
Alpha toxin forms holes in the membrane. Beta toxin degrades sphingomyelin
Positive PPD with no risk factors
> 15 mm of induration needed for treatment
Ziehl-Neelsen stain
is an acid-fast bacterial stain
Think Mycobacterium
prophylaxis with azithro and clarithro with CD4+ counts under 50
Sterile pyuria
N. Gonorrhea is intracellular and is not detected on urinalysis or standard urinary culture
Distinguishing S. mutans from S. pneumoniae
S. mutans are optochin resistant, alpha hemolytic and insoluble in bile
S. Pneumoniae is sensitive to optochin and bile soluble
Anaerobic bacteria above the diaphragm
use clindamycin
N. Meningitis
can be differentiated from other meningitis due to the petechial skin rash
HIV positive brain biopsy
think about varicell and herpes encephalitis which present with Cowdry’s type A inclusion bodies
Intraerythrocytic protozoan transmitted by the Ixodes tick
Babesiosis activates compliment fever, chills, myalgias, GI, dark-colored urine not usually have rash Maltese cross typically have low C3, C4, and CH50
Viral myocarditis
Most common cause is Coxsackie B which is a SS linear non-enveloped RNA virus
new murmur from either mitral or tricuspid regurg
biopsy of mononuclear cell infiltration of the endomyocardium
Bartonella henselae in HIV
causes bacillary angiomatosis in HIV+ patients, painless red-purple lesions that bleed easily
ancylotoma duodenale
roundworm fecally excreted and dermally acquired
few acute problems
nutritional insuffiencies secondary to intestinal malabsorption
trypanosoma cruzi
appears as a flagellated protozoan on peripheral blood smear
achalasia
Cryptosporidiosis
chronic, watery, non-bloody diarrhea
malabsorption and vitamin deficiency
acid-fast oocysts in stool
HIV tax
conical, envelope, rna
visceral leishmaniasis
sand-fly disease, southeast asia, nonspecific syndrome
fever, weight loss, malaise, and splenomegaly
Dracunculiasis
guinea worm
copepods that ingest larvae, traverses GI mucosa and matures in abd cavity then travels subcutaneously to erupt as a blister in lower mucosa
purulent thin whitish filament
HiB
virulence factor is IgA protease
Plasmodium Falciparum treatment
artemisinin-based combination therapy (ACT)
dihydroartemisinin and piperaquine moa unknown
rhinocerebral mucormycosis
caused by zygomycetes (mucor, rhizopus)
seen in DM pt.
black nasal discharge
Histoplasma
most common cause of chronic mediastinitis ahead of TB and radiation
Quellung rxn
detects encapsulated organisms:
HiB, Strep pneumoniae, N. Meningitidis, Klebsiella, Salmonella
Adenovirus
URI, conjunctivitis, aseptic meningitis, ear infection
rarely hemorrhagic cystitis in young children
double stranded naked
linear DNA
Pneumocystis pneumonia and Toxoplasma gondii HIV prophylaxis
TMP-SMX
Transformation
uptake of free-floating DNA by competent bacteria
echinococcosis granulosus
hepatic cysts
treat with albendazole
Legionella pneumophila
detected using urinary antigen test
gram neg rod
stain with silver
R.Rickettsii
invasion of bacteria into vascular endothelial cells
Rotavirus
non-enveloped, double-stranded RNA
HPV
non-enveloped double-stranded circular DNA virus
Reactive arthritis
possible causative pathogens:
chlamydia trachomatis, yersinia, salmonella, shigella, campylobacter, e. coli, c. diff, chlamydia pneumoniae
Coccidioidomycosis
thick-walled, non-budding spherules
treat systemic=amphotericin B
mild= fluconazole/itraconazole
Erysipelas
erythematous, raised, well-demarcated rah
Strep pyogenes most common
treat with oral amoxicillin
S. pneumoniae virulence factor
polysaccharide capsule
Rubeola
paramyxovirus that has giant cell pneumonia as a sequelae
Tularemia
can be transmitted by inhalation and is a potential bioweapon
Tropical Spastic Paraparesis
caused by HTVL-1 that presents w. LE pins and needles, bladder problems, and sexual problems
dx. presence of retroviral proteins
Pseudomonas Aeruginosa
Gram-negative, aerobic, non-lactose fermenting and oxidase positive rod
Exotoxin A inactivates EF2
