microbiology Flashcards
Compare and contrast paralysis of polio, guillan-barre, botulism, transverse myelitis, and enteroviral meningitis?
This is most likely poliomyelitis; the asymmetrical weakness, proximal greater than distal, and preserved sensory innervation are typical. In contrast, the paralysis of Guillan-Barre is typically ascending in nature; botulism usually affects the cranial nerves first, and transverse myelitis would cause both sensory and motor dysfunction as well as increased DTR distal to the lesion. Enteroviral meningitis would rarely present with just peripheral paralysis, and would usualy have meningeal signs.
acid-fast staining bacteria that produce diarreha in AIDS pts are 4-6 microns in diameter are cryptosporidum and not mycoplasma because
althought it produces diarrhea in AIDS pts mycoplasma is intracellular and would be much smaller than this
chancriod caused by haemophlus ducreyi
- stain, shape
- growth media, and growth pattern
- treat
- lesion
-plemorphic gram negative rod
-chocolate agar, “school of fish” growth pattern
-whole blood agar with satelilite phenomenon around staph aureus.
treat with azithromycin or ceftriaxone
-forms genital papules with red base, which can become ulcerativite and painful with accompanying lymphadenopathy
genital lesions
- haemophilus ducreyi
- HSV
- chlamydia
- HPV
- spirochetes
- ulcerative and painful
- vesicular and painful
- non painful, lymphadenopathy and elephantiasis
- genital warts not ulcers-form koilocytotic squamous cels
- hard and nonpainful
cigar shaped yeast
sporothrix schenckii
gram neg rod requiring cysteine
francisela tularensis
gram neg rod with bi polar staining
yersinia pestis
large spirochete
borrelia burgdorferi
box car shaped, gram positive rod
bacillus anthracis
viruses: transmission/common diseases:
- aerosol
- fecal-oral
- parenteral
- sexual
- arthropods
- respiratory viruses
- gasteroenteritis viruses
- enveloped viruses (direct transfusion or transplatation)
- enveloped viruses that are fragile in environment
- viral encephalitis (except HSV-direct contact with infected tissues)
toxins encoded by lysogenic phages
cholera toxin, shiga toxin, O antigen of salmonella, erthrogenic exotoxin of streptococcus pyogenes, and diptheria, and clostridium botulinum
name bacteria that are natural transformers, i.e take in free DNA from environment.
SHiN
S. pneumoniae
H. influenzae
Neisseria
window period in acute hepatitis B
when neither hep B antigen or it’s antibody can be detected in serum. b/c anitgen-antibody complexes are precipitated out. still positive for anti HBe and anti HBc
risk of hep B infection after positive needle stick
-most common outcome/ %
-other outcome/ %
% that recover-% that develop chronic-% that carry and no symptoms-% that carry with symptoms
- subclinical disease followed by complete recovery 60-65%
- 20-25% develop. acute hepatitis: most recover (90%), 10% develop chronic hep B
- chronic hep B: most asymptomatic carriers (90%), 10% symptomatic and infectious
lung sputum:
- pink (salmon color)
- red currant jelly
- rusty-redish color
- PE difference b/t last two?
- staph aureus
- klebsiella
- strep pneumoniae
- age (older=klebsiella), dsypnea and high fever
previous healthy person in southwest US who develops septic shock should be evaluated for?
plague-yersina pestis.
double strained, DNA, naked, icosahedral virus
adenovirus
negative sense, single strand RNA, non segmented, helical, enveloped
paramyoxviridae
negative sense, single strand RNA, 8 segments, helical, enveloped
orthomyxovirus-influenza
positive sense, single strand RNA, helical, enveloped
coronaviruses-common cold, acute pharyngitis, SARS-CoV (acute respiratory distress syndrome)
hepevirus-HEV
positive sense, single strand RNA, naked, icosahedral
picornaviruses-common cold and calciviruses-norovirus-viral gastroenteritis
leukocyte esterase test in urine is indicative of?
what about nitrite reactivity? rule out which bacteria family?
neutrophils-bacteria infection
-enterobacter. sp (enterbacter, e.coli, klebsiella, proteus) forms nitrite from nitrate-no reactivity=negative for enterbacter.
what causes pseduoappendicitis and grows in colder temps?
yersinia enterocolitica (from contaminated milk) also associated with colder climates b/c it growas at 22C.
types of E. Coli (PITcH)
Pediatric-enteropathogenic, no toxin, inflammation and diarrhea
Inflammatory-enteroinvasive, no toxin, invasion leads to inflammatory response no antibiotics needed
Traveler-enterotoxigenic, traveler’s diarrhea activate intestinal adenylate or guanlyate cyclase-increase cAMP
Hamburger- enterohemmorrhagic, O157:H7, shiga like toxin, bloody diarrhea, inhibits 60S
Seizures and Ct scan showing space occupying lesions, pt from mexico, south central america (brazil), philippines, and southeast asia. disease and organism?
Cysticercosis from ingestion of larval cysts of Taenia solium. (in pig swine) CNS invovlement=neurocysticercosis
larvae infection from dogs
echinococcus granulosus
larvae infection from new pets
toxocara carnis-visceral larva migrans (granulomatous inflammation, no calcification), toxoplasmosis (ring-enhancing lesions)
bacteria cause of spontaneous abortion. source
listeria monocytogenes, unpasteurized dairy food and deli meats
rat bites
spirillum minus or streptobacillus moniformis
ring-enhancing lesion
lesion with dark core (necrosis) and bright lesion peripherally (toxoplasma gondii)
bird droppings transmit? (2)
opportunistic fungal infections-cryptococcosis and histoplasmosis
cooling systems
legionella pneumophila, fatal pneumonia
traveler from Hawaii with fever
leptospira interrogans- freshwater contaminated with urine
intracellular gram negative rods (3)
legionella pneuomphila, brucella, francisella
erthyomycin and not cephalosporin is used to treat mycoplasma pneumoniae because
cephalosporins and penicillins interfere with peptidoglycan (cell wall synthesis) and mycoplasma doesn’t have a cell wall.
cylindrical white worm, large size, fecal contamination from other humans
ascaris lumbriciodes-nematode
petechial rash and tenderness over tendon sheaths (tenosynovitis), ankles and knees are mc invovled.
neisseria gonorrhoeae- reinfection occurs b/c antigenic variation and phase variation of pili
organisms transmitted by Ixodes tick
borrelia burdorferi, babesia microti, and ehrlichia
organisms transmitted by dermacentor tick
rickettsia rickettsii and francisella tularensis
needs cholesterol to grow
mycoplasma
low tension oxygen needed for growth (3)
microaerophiles camplyobacter, helicobacter, borrelia
source/organism ground beef/salad greens poultry rice packed fish.canned alkaline veggies
E. coli Campylobacter and salmonella Bacillus cereus E. coli Clostridium botulism
tumors associated with EBV
nasopharyngeal carcinoma, African form of Burkitt’s lymphoma, and B-cell lymphomas
aphthous ulcers
aka canker sores-painful shallow in oral cavity, SLE and Crohn disease
atelectasis
collapse of parts of the lung
distinct nuclear and ill-defined cytoplasmic inclusions
CMV
Cowdry type A inclusions
HSV-1
greatly enlarged oligodendrocyte nuclei with glassy amorphic viral inclusions
PML progressive multifocal leukencephalopahty-infects oligodendroglia caused by JC virus
microglial nodules containing multinucleated giant cells
HIV encephalitis
preferred diagnostic test of cryptococcus neoformans
latex particle agglutination test detects capsular antigens in CSF, india ink is not at sensitive
pseudomembrane on the oral and nasal mucosa-fribrinous coating=
corynebacterium
grows inside of TB lesions
aspergilloma
risk factors for etopic preg
PID (chlamydia trachcomatis or neisseria gonorrhoeae), diethylstilbesterol (DES) and induced abortion
food poisoning: food, symptoms, incubation period
- staph aureus
- bacillus cereus
- clostridium perfringens
- E coli
- shigella sonnei
- pastries, nausea and vomiting, 1-6hrs
- rice, nausea and vomiting, 6hrs (heat liable)
- re-heated meat dishes, diarrhea 8-24hrs
- watery diarrhea or bloody diarrhea
- poor hygiene, fever cramps, diarrhea, 1-4 days
gram-positive cocci with variable hemolysis
enteroccocus
pryogenic toxin (A-C) and not M protein or hyaluronic acid capsule is the cause of fever and rash in strep pyrogenes because
hyaluronic acid capsule in non-immunogenic and the M protein is anti-phagocytic surface protein. whereas the pyrogenes A-C are phage encoded and cause rash
type I hypersensitivity and not neutrophilia results from francisella tularensis because
it’s an intracellular pathogen and activates T-cell and macrophage mediated immunity leading to granuloma formation. neutrophilia is normal response to extracellular pathogens and would not be expected with francisella
missouri, arkansas, oklahoma
francisella tularensis-50% cases occur here
IgA protease and not hyaluronic capsule mediates strep pneumoniae’s attachement to repiratory mucosa because
b/c strep pneumoniae does not produce hyaluronic acid capsule, strep pyogenes does,
pt from South Asia with rash on “palms and soles” most likely has syphilis and not ricketsia rickettsii because
rickettsia begins on ankles and wrist and spreads to midline, it can involve palms and soles but does not occur in Southeast Asia and would not affect a traveler b/c is requires a Dermacentor tick vector.
intracellular prokaryote that elicits the Weil-Felix rxn
leptospira interrogans
spirillar prokaryote with internal flagellum
syphillis
a pt with history of colerectal cancer, splinter nails and heart murrur has strep bovis and not strep mutans because
s. bovis is associated with colon cancer and endocarditis s. mutans or s. sanguis are associated with dental work, and endocarditis on previously damaged valves (heart valve defect)
diptheria toxin inactivates translation elongation and not transcription elongation because
the toxin inactivates eEF2 (eukaryotic elongation factor 2) via ADP-ribosylation. transcription termination is usually affected by chromatin structure
pt with pulomnary crackles and history of urinary retention sencondary to BPH has E. coli and not s.pneumoniae because
E. coli is associated with UTIs and cystitis
virus/first step after entering cytoplasm
- negative-sense single stranded RNA
- negative-sense double stranded RNA
- positive-sense RNA exception?
- double stranded DNA
- convert negative to positive sense mRNA with RNA dependent RNA polymerase (ex. paramoxyvirus)
- viron core enzymes uses negative sense strand as a template to make mRNA (reovirus)
- translation of protein using cellular ribosome (exception is retrovirus-uses viron RNA dependent DNA polymerase to created double stranded DNA and parasitive the host)
- use cellular DNA-dependent RNA polymerase to create mRNA, poxivirus can do this in cytoplasm with it’s own DNA-dependent RNA polymerase
transposons and not restriction endonucleases play a role in multidrug resistance because
transposons are mobile DNA the move and can copy themselves from DNA molecule to another. they usually contain genes for drug resistance and help to build multi-drug resistant plasmids. restriction endonucleases cleave DNA at site-specific base sequences. they are involved in transposon movement but are not directly how drug resistance is acquired.
VDRL and not microhemaglutination is used to test for 2ndary syphilis because
VDRL is best used first b/c of low cost and ease, use hemagglutination or FTA-ABS as confirmatory tests
a child with behavior changes, intellectual deterioration, laziness, clumsiness, involuntary jerky movements has measles and not polio because
antibodies directly against measles can lead to SSPE there’s not treatment can pt dies. polio causes GI disturbances, viremia, and paralysis
quesiotn 27
answer
pt in shock is mediated by lipid A and not lecithinase because
shock is mediated by gram negative release of endotoxin lipopolysaccharide (LPS) whose most toxin component is lipid A. lecithinase is a toxin produced by clostridium perfringens to cause holes in cell membrane.
pt with ear pain and drainage and pus from ear with swelling and tenderness of mastoid bone is caused by pseduomas aeuginosa and not strep pneumo because
p. aeruginosa causes malignant otitis externa which can spread to mastoid bone. strep pneumo causes otitis media in children (no pus drainage or malignancy)
ecthyma gangrenosum
black necrotic center and raised hemorrhagic ring p. aeruginosa causes this lesion
child from daycare with 3-day history of bloody pus filled diarrhrea has shigellosis (aka?) and not Norovirus because
norovirus does not cause bloody or diarrhea or pus and only last 24-72 hrs. shigella (baccillary dysentery) is not self limited and can be deadly if pt becomes to dehydrated. note rotavirus can also cause diarrhea in daycare but is not bloody and is also self-limiting.
HIV T cell destruction affects anti-p24 and not ant-env becuase
env proteins (gp41/gp40) are constantly changing and the IgM anti body can be made in the absence of TH cells. anit-p24 will decline b/c it’s not IgM anitbody.
the toxin similar to cholera is heat labile toxin of E. Coli and not verotoxin of E.Coli because
both heat labile and cholera toxin activate adenylate cyclase by ADP ribosylation of a GTP-binding protein. verotoxin is similar to shiga toxin and causes hemorrhagic diarrhea due to 28S and 60S ribosomal protein synthesis blockage
tuberculin,sufatides, mycolic acid
mycobacterium tuberculosis.
- surface protein that elicits type I hypersensitivity
- inhibit fusion of phagosome and lysosome allow M. T to survive inside macs
- long fatty acid chains that protect M.T. from temp, pH changes and gram stain.
methenamine-silver staining cysts causing pneumonia in AIDS, “crushed tennis ball”
P.jiroveci
iodine staining intraepithelial inclusion bodies
chlamydia
Guarnueri bodies
poxviruses, used to be called Cowdry type B inclusion bodies,
negri bodies
rabies virus
CAMP test positivity
test for incomplete hemolysin group B strep (streptococcus agalactiae)
muscarinic antagonist symptoms (hot as a hare, mad as a hatter etc…. )+ muscle weakness=
botulism toxin affects both muscarinic and nicotinic (muscle weakness) b/c of overall decreases Ach release. atropine only works on muscarinic
pt with cough, foul smelling sputum and oxidase positive cultures with fruity odor has
pseudomonas aeruginosa and CF
pt with diarrhea and infection of small intestine with cresent shaped protozoa has giardia lambila and not entamoeba histolytic because
g. l. infest small intestine and has face like appearance on smears vs e.h. which tends to infect large intestine or liver
no cell wall and sterols in membrane
mycoplasma
spore formation occurs during stationary phase and not death phase because
stationary phase toxins build up and bac aren’t dying yet.
alpha toxin
C. perfringens toxin cause myonecorsis (gas gangrene)
SSPE
rubeola-subacute sclerosing panencephalitis
order of transfer of Hfr donor genes is
from oriT towards the tra operon. tra operon is never transferred. genes closer to oriT are more likely to be transmitted
pt with urinary retension and BPH and pulmonary systems is due to e.coli and not strep pneumonae because
e. coli related cycstitis can lead to bacteremia, shock culminating in acute respiratory syndrome (ARD). strep pneumoniae can cause the community acquired pneumonia but does not explain the GU symptoms
syncytia formation and not viral hemagglutinin protects mumps from extracelluar immune complex because
syncytia (allows mumps virus to travel from cell to cell) why cell medicated immunity (live vaccine) is necessary. viral hemagglutin is a complex forms with neuramindase and is not found in mumps and can also be neutralized by antibodies. (-mivir drugs for influenza)
during summer most viral encephalitis is transmitted via
arthropods- St. Louis virus, west nile, eastern/western equine and togaviridae
reason histoplasmosis is not communicable from person to person
b/c it’s found intracellularly in cells of reticuloendothelial system and lungs
intranuclear inclusion bodies and multinulceated giant cells
HSV
homologous recombination (def)
linear DNA pieces are integrated into bac chromosomes with rec A. must have it or can only use F+ to F- conjugation
name 6 capsulated organisms
strep pneumo, klebsiella pneumo, haemophilus, p. aeruginosa, n. meningitidis, and c. neoformans (think SHiN Neo KlP)
pt from Africa with dermal granulomas with rare acid fast bacilli, affecting cooler parts of body (nose, ears etc..) has tuberculoid leprosy and not rihnoscleroma because
rhinocleroma is a granulomatous infection of nasopharynx associated with klebsiella rhinoscleromatis and would have gram negative rods not acid fast cyts
newborn with respiratory distress and needle biopsy shows spherical bodies with sharp outlined walls and stained with methenamine silver has pneumocystis jiroveci and no RSV because
RSV would be giant nuclear cells or syncytia in sputum. “spherical cells with outlined walls”-pneumocystis jiroveci
name three bacteria that can cause non specific epidydymis and orchitis and their associated age group. name most common
N. gonorrhoeae-young, most common
E. Coli- older
Pseuduomonas-older
pt with AIDS and diarrhea, acid-fast stool has cryptosporidium parvum and not cryptococcus neoformans becuase. also mechanism of pathogenesis is intracellular multiplication in the bush border and not through a toxin the ribosylates Gs becuase
cryptococcocus neofromans causes meningitis not diarrhea.
it’s usually self-limiting in healthy pts, mechanism is through direct lysis of cells at bush border as parasites multiply there. ribosylation of Gs is a toxin from E. coli. plus cryptosporidium doesn’t produce any toxins
pt from Panama with relasping flu like symptoms and blood smear with punctate granulation and RBCS with oval bodies has plasmodium vivax and not P. falciparum because
Schuffner dots indicates vivax or ovale, also these can cause relapsing episodes due to hypnozoites. it’s vivax not ovale b/c vivax is in the Western hemisphere.
diptheroid vs c. diphtheriae. name of test that differentiate b/t the two.
d-non-toxin producing strain of c.d., normal flora organism
c.d-is a d. that has been infected with a bacterium with a phage encoding the toxin-lysogenic conversion
ELEK test
can ELISA and WEstern Blot be used to diagnosis newborns with HIV?
NO, only the mother b/c the tests indicate presence of IgG antibodies (which could have crossed placenta from mother even if the virus hadn’t). must use PCR or viral cultures to determine state of infant.
name 5 types of neurosyphilus
acute septic meningtis, meningovascular, and tabes dorsales, general paresis, optic atophy
acute syphilitic meningitis
headache, meningeal irriation, and crainial nerve abornalities
meningovascular syphlilis
unilateral umbness, parethesias, vertigo, upper-lower estremety weakeness, and personality changes.
tabes dorsalis syphilis
Argyll-robertson pupils (accomodate but don’t react to light), stabbing pain, loss of vibration sensation and reflexes
paresis mnemonic for neurosyphilis
Personality, Affect, Reflexes, Eyes (Argyll-Robertson pupils), Sensorium defects, Intellectual decline, and Speech deficiencies .
what stain us used to diagnose syphilis?
screen with VDRL and confirm with FTA-ABS
poxvirus replicates where?
cytoplasm
external otitis is caused by pseudomonas aeruginosa and not streptococcus pneumoniae because
strep pneumo causes otitis media .
pseudo a. can also lead to temporal bony erosions and soft tissue swelling on CT (invades underlying epithelium)
spherules found in deserts that cause fungal meningitis
coccidiodies immitis (San Jaoquin Valley Fever)
pt acquires ascaris lumbricoides from ingestion of eggs from human feces and not from infected pet b/c
ingestion of eggs from pet sources leads to visceral lava migrans (anorexia, fever coughing, wheezing, abdominal pain, maybe rash or hepatosplenoegaly)
hyphae with rosettes of microconidia
enviromental form of sporothrix schenckii
mcroconidia
environmental form of histoplasma casulatum
protein in E. Coli that causes neonatal disease is K1 capsule and not biofilm production because
k1 prevents phagocytosis, biofilm production is seen in staph epidermidis, and strep mutans and enteroaggregative E. Coli but not the E. Coli strain that infects neonates
two infections that can cause damage to dorsal columns and roots of spinal cord.
diphylloborthrium latum(ingest poorly cooked fish)- will also have pernious anemia and B12 deficiency tabes dorsalis syphilis-look for previous signs of 2ndary and primary syphilis.
diagnose signs of secondary syphilis with VDRL and not dark field microscopy because
VDRL is easy and less expensive. chancres in primary syphilis can be biposied.
which causes pandemics (worse), genetic shift or drift
shift
elderly pt with pneumonaie from nursing home and reddish sputum, has klebsiella and not strep. pneuom because
although strep. pneumo is more common in this group it’s sputum is rusty colored and klebsiella is more common in nusring homes
pleural friction rub
leathery creaking sound produced by movement of roughed pleural surfaces against each other
pt with CSF sample showing decreased glucose (50), and lymphocytes likely has a fungal not viral infection because
vial infection would have normal glucose
67 y/o w. from nursing home with positive rapid influenza test, flu like symptoms, and cavitary lesions on X-ray has a bacteria with gram positive, catalase, positive, couagulase-positive coccus and not silver staining cyst because
pt has influenzae complicated by staph aureus infection. other common bac that produce pneumonia in context of influ are haemophilus influ and strep pneumo. staph is most destructive.
pneumocystis jirovecii causes atypical pneumo in immunocompromised or infants
4 y/o w. with pain in fingers and toes and raised facial rash, severe anemia, has parvovirus and not coxsackie because
parvovirus causes ertythema infectious (in children) and severe anemia. coxsackie can cause a cold like illness, herpangina, myocarditis and meningitis
42 y/o w. with PMH of heart transplant surgery and toxoplasmosis acquired it from reactivation of latent infection and not ingestion of cat feces because
ingestion of cat feces would have caused other symptoms (lymphadenoapthy,and low grade fever) also this method of transmission is rare in the US. toxo last in host for lifetime and usually presents with no symptoms unless immunocompromised or immunosuppressed (from transplant)
18 month g. with otisis media has what bacteria? the capsule and not the lipopolysaccahride is the most important virulence factor because
the capsule protects against phagocytosis. strep pneumonia, is gram positive. only ram-negative have have lipopolysaccharide.
most common cause of atypical pneumonia, how do you test for it?
atypical because it doesn’t respond to ampicillin, but responses to erthromycin, mc is mycoplasma pneumonia. test using cold agglutinins
ecthyma gangrenosum
lesion in pseudomonas septicemia black necrotic center with raised hemorraghic ring on outside
most common transmission of neonatal encepahalitis
passage through infected birth canal during active infection
pt with bacteria meningitis at base of brain has
strep pneumoncitis menningitis- only bacteria that causes meningitis at base of brain.
