MICROBIOLOGY Flashcards by megan king

what rickettsia rashes:
starts in periphery and moves to trunk
starts on trunk and moves to periphery

rickettsia ricketsii = periphery to trunk
(starts on ‘wrists’)
typhus (rickettsia prowazekki) = trunk to periphery
(starts on ‘trunk’)

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name the 3 comma shaped rods

campylobacter jejuni (invasive)
vibrio cholera
helicobacter pylori

all oxidase positive
all facultative anaerobes

all gram negative

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listeria can cause meningitis in what age group

elderly >60yo

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does coxiella cause a rash

from spores in animal droppings (aerosol)
obligate intracellular

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pneumonia
headache
hepatitis
fever
working with/near animals

coxiella

brucella = undulating fever

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spaghetti and meatballs histology

malassezia furfur

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francisella tularensis relies on clearance by ?

cell mediated immunity
(T cells & macrophages)

facultative intracellular

i.e. same as listeria, mycobacterium

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who is IV penicillin given to to prevent s. agalactiae infection in newborn

mother intrapartum

at 35 weeks - swabbed, can colanise vaginal tract

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positive hippurate test
positive CAMP test
seen in

s. agalactiae
(group B strep)

s. pyogenes hippurate test negative

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bacitracin resistant
PYR test negative

s. agalactiae
(group B strep)

s. pyogenes bacitracin sensitive
PYR test positive

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what is a predisposing factor to mucormycosis/rhizopus

diabetic ketoacidosis

fungus multiplies in blood vessel walls, in location shigh in glucose/ke

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fungus with non-septate 90% (wide) angle branching

mucormycosis/rhizopus

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febrile illness
followed by weakness, dyspnoea
severe anaemia
low reticulocyte count
sickel cell disease

viral cause

parvo B19
(ss DNA non-enveloped)

aplastic crisis
destruction of erythroid precursor cells

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pasteurella multocida can cause

osteomyelitis

dog and cat bite (gram negative coccobacillus)

catalase +, oxidase +, capsule, bipolar staining
also cellulitis

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salmonella or shigella acid labile

salmonella = lable
shigella = stable

salmonella infection more risk if less acidid i.e. stomach acid lower

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bacteria (4) that increase adenyl cyclase (cAMP)

E coli
V. cholera
B. pertussus
B. anthracis

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bordetella pertussus activates adenylate cyclase (cAMP) by inactivating

inhibitory subunit (Gi)

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what stain is used for bartonella henselae (cat scratch)

silver stain

hard to identify on stain

facultative intracellular organism - Tx with doxycycline or macrolides (penetrate cell)

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what neisseria species is facultative intracellular

N. gonnorrhoea

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bite
nontender nodules
blindness
microfilariae in nodules
travel overseas

onchocerca volvulus
black fly

black skin nodules
river blindness
Tx ivermectin

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conjugation

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transfer of plasmid between 2 bacteria

(conjugal bridge - **sex pilus **used to mate)

transduction

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‘packaging error’
bacterial DNA may be packaged into plasmid

infects another bacterium, transferring genes

transposition

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transposon copy and excise itself into same/another DNA

bacteria

fever
N & V
periorbital oedema
myalgia

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trichinosis
(trichinella spiralis)

encyst in striated ms
undercooked meat

larvae enter bloodstream

intestinal nematode (round worm)
Tx: bendazoles
(mbendazole) - acts on microtubues

fever, chills myalgias weakness, headache haemolytic anaemia asplenia risk ring forms / tetrads on Giemsa stain | what vector

**babesia _microti_** (Ixodes scapularis - deer tick) | malaria-like illness protozoan - intra-erythrocyte ## Footnote borellia burgdorferi - Lyme disease (spirochete)

spirochete NE USA Lyme disease transmitted by Ixodes scapularis

**borrelia _burgdorferi_**

VZV extending posteriolaterally to R of umbillicus is located aht which DRG

T10 | umbilicus location T10 dermatome

CMV is not susceptible to _\_\_ it does not possess _\_\_

guanosine analogs (acyclovir, valcyclovir) thymidine kinase

neonate **hearing loss** seizures petechial rash **intracranial calcifications** organomegaly

CMV neonate passes via placenta | mother close contact with children

fever myalgia atypical lymphocytosis abnormal liver enzymes immunocompromised host prominent inclusion bodies | atypical: colitis, encephalitis, pneumonia, oesophagitis, retinitis

CMV maternal

measles triad

cough coryza conjunctivitis | rash **face --> cephalocaudal**

measles (rubeola) type of virus

paramyxovirus (-sense enveloped RNA)

children fever cough coryza conjunctivitis maculopapular rash - start at head *(excludes hands/feed)* lymphadenopathy red macules with blue-ish center buccal mucosa

measles (rubeola)

complications of measles (2)

Subacute Sclerosing Panencephalitis (SSPE) Giant cell pneumonia | Brain & Lung ## Footnote Subacute Sclerosing Panencephalitis (**SSPE**) - (neurodegenerative) **giant cell pneumonia -immunosuppressed**

what vitamin is associated with severe measles disease and complications

vitamin A | provide supplement, especially malnourished

West Nile virus causes (2)

meningoencephalitis acute asymmetric flaccid | flavivirus (+sense enveloped RNA)

HSV lies dormant where? reactivation causes? | genital HSV

sacral doral root ganglia recurrent genital ulcers

VZV lies dormant where? reactivation causes?

sensory dorsal doot ganglion *herpes* zoster (shingles)

m/c cause haematogenous osteomyelitis

**S aureus** (m/c) S pyogens (2nd) | children long bones LL (adults - vertebrae, IVDU, catheters)

m/c cause osteomyelitis is SSD patients

salmonella

what effect do antibiotic use have on vaginal flora balance

**decreased** number of **gram positive (+) lactobacilli** | facilitates **candidia** growth

E coli can cause sepsis, pneumonia and _\_\_

ARDS

severe diarrhoea in AIDS pt

cryptosporidium parvum (small round oocysts on colonic epithelial surface) | watery diarrhoea abdominal cramps ## Footnote transmission: oocysts in water wt loss, fever, dehydration, orthostasis, n&v dX: STOOL ANTIGEN TESTING - **LUMINAL OOCYSTS,** *acid fast staining* i.e. carbol fushcin, zeel-neelson GIARDIA LAMBLIA - also watery diarrhoa & flagellated pear shaped trophozoite, can demonstrate cysts (usually mentions exposure to unfiltered water) - if AIDS more likely cryptosporidium

vector - fleas, animals (cats) gram negative bacillus, encapsulated bloody ddiarrhoea fever, leukcocytosis, abscesses ulcers, buboes - LN mass pneumonia New Mexico (SW USA)

yersinia pestis | bacteremia, DIC bilateral infiltrates **Tx aminoglycosides, doxycyline** ## Footnote black death bubonic plaque

cutaneous erythema warmth induration following inocculation injury/abrasion fever tachycardia leukocytosis

cellulitis | strep pyogenes (GAS) - non purulent staph aureus - purulent

# gram positive, chains, B haemolytic, bacitracin sensitive a cause of cellulitis ## Footnote or pharyngitis, scarlet fever, necrotising fasciitis, glomerulonephritis, rheumatic fever

strep pyogenes (GAS) pyogenes is not | anothe cause would be staph aureus - puruent

features of strep pyogenes | GAS

gram positive chains B-haemolytic bacitracin sensitive non-purulent in cellulitis

Legionella pneumophilia can be treated by

fluroquinolones - i.e. ciprofloxacin macrolides

HIV generalised tonic clonic seizure small solitary enhancing lesione frontal lobe lymphocytes, plasma cells, macrophages (biopsy) crescent shaped organisms with central nuceli | Tx with sulfonamide and pyrimethamine

toxoplasma gondii | ingestion of oocyts from cat feaces or infected meat ## Footnote protozoan parasite

what 2 organisms can enter the brain by crossing the cribiform plate

naegleria fowleri murcormycosis ## Footnote **naegleria fowleri **- freshwater amoeba, meningoencephalitis, mortality 100%, affects communocompetent and immunocompromised **murcormycosis** - fungal, common in DM, direct sinus invasion

a auseus virulence factor that kills leukocytes and causes necrosis

leukocedin (Panton-Valentine Leukocidin (PVL)) | skin and soft tissue infections necrotizing pneumonia ## Footnote 🛡️** Immune evasion:** Protein A: Binds Fc region of IgG → prevents opsonization and phagocytosis Capsule: Anti-phagocytic Leukocidins (like PVL): Kill neutrophils ** 🧪 Toxins:** Hemolysins: Lyse RBCs and other cells Exfoliative toxins: Cause scalded skin syndrome Toxic Shock Syndrome Toxin (TSST-1): Superantigen → massive T-cell activation Enterotoxins: Preformed in food → rapid-onset food poisoning ** 🧷 Enzymes (spread/invasion):** Coagulase: Clots plasma → walls off infection Hyaluronidase: Breaks down connective tissue Staphylokinase: Dissolves clots Lipases: Help in skin colonization DNases: Break down neutrophil extracellular traps (NETs)

MICROBIOLOGY Flashcards

(51 cards)