08a: Micro Flashcards by Nuna H

Which part of cell wall structure is unique to gram positive bacteria?

Lipoteichoic acid

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Mycobacteria doesn’t gram stain well because:

Cell wall has high lipid content

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Chlamydia doesn’t gram stain well because:

Intracellular

2. Low muramic acid in cell wall

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Ziehl-Neelsen stain (carbol fuchsin) is used to stain (X). What are the steps that go into staining?

X = acid-fast bacteria (Mycobacteria, Nocardia) and protozoa (Cryptosporidium)

Carbol fuchsin (red) dye
Acid-alcohol wash
Methylene blue counterstain

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(X) bacteria is cultured on (Y) agar, which contains potato extract

X = Bordetella pertussis
Y = Bordet-Gengou

(Bordet for Bordetella)

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Dark black, slightly luminous colonies on cysteine tellurite agar

C. diptheriae

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Legionella grown in which agar?

Charcoal yeast extract agar, buffered with Cys and iron

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Fungi grown on which agar?

Sabouraud

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(X) antibiotics are ineffective against anaerobes because they require oxygen to enter cell

X = aminoglycosides

“AminO2glycosides require O2”

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List bacteria that are obligate intracellular. They must be in cells because they rely on (X)

Rickettsia
Chlamydia
Coxiella

X = host ATP

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T/F: H. pylori is catalase positive

True (also urease and oxidase positive)

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Bacteria that produce urease (increase/decrease) pH of environment

Increase (hydrolyze urea into ammonia and CO2)

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Bacteria bind and import short pieces of environmental, naked chromosomal DNA from another bacterial cell lysis

Transformation

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F(+/-) contains genes required for (X). When “mating bridge” is formed, what’s being transferred?

F+
X = sex pilus and conjugation (with F- cell)

Single strand of plasmid DNA to F- cell, making it an F+ cell

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F+ plasmid becomes incorporated into bacterial chromosomal DNA, making F+ cell a(n) (X) cell. If it comes in contact with F- cell, what can occur?

X = Hfr (high-frequency recombination)

Conjugation with F- cell allows Hfr cell to transfer/replicate part of chromosome (F- cell becomes “recombinant F- cell”)

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List the 5 bacterial toxins encoded in lysogenic phage

“ABCD’S”

group A strep erythrogenic toxin
Botulinum toxin
Cholera toxin
Diphtheria toxin
Shiga toxin

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Recent traveller to Latin America, Asia, or Africa presents with fever, HA, watery diarrhea that has become bloody. Hepatosplenomegaly and faint, erythematous maculopapular lesions on chest/abdomen. Dx?

Typhoid fever

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Kidney transplant patient with low-grade fever and pneumonia symptoms. Small, round organisms staining red with mucicarmine stain of bronchoalveolar fluid. Dx?

Cryptococcus neoformans lung disease

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Pseudohyphae with blastoconidia

Candida

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(X) bacteria produces (Y) factor, which enlarges area of hemolysis formed by S. aureus

X = Group B strep (agalactiae)
Y = CAMP

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Gram positive, Catalase negative, PYR positive, gamma hemolytic

Enterococcus

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(X) assay can be used to test for TB in patients with BCG vaccine due to fewer false (pos/neg)

X = Interferon gamma release assay

False pos

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AIDs patient with CD4 count recently dropped under 50: what’s a key bacterium that he should now receive prophylactic Rx for?

Mycobacterium avium (with Azithromycin)

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Penicillins/cephalosporins work by binding (X). Vancomycin works by binding (Y).

X = Penicillin-binding proteins (ex: transpeptidases)
Y = glycoproteins

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Prevention of neonatal tetanus involves efforts focused on:

Vaccination of pregnant women and those of child-bearing age (with inactivated tetanus toxoid) Also cord hygiene

Cat bite resulting in cellulitis. Most likely infectious cause:

``` Pasteurella multocida (#1) Could also be Bartonella ```

Pasteurella multocida can cause which two key presentations/diseases?

Osteomyelitis and cellulitis

Patient presents with infected calf injury that has mouse-like odor

Pasteurella multocida infection

T/F: Bacterial vaginosis can be prevented via condom use

False - not a sexually transmitted disease

(X) are mulberry-like inclusions in cytoplasm of either monocytes or granulocytes. Which disease(s)?

X = morulae 1. Ehrlichiosis (in monocytes) 2. Anaplasmosis (in granulocytes) "MEGA berry = Monocytes Ehrlichiosis, Granulocytes Anaplasmosis"

Chlamydia serotypes L1, L2, L3 cause:

Lymphogranuloma venereum (small painless ulcers on genitals with swollen painful inguinal lymph nodes that ulcerate)

(Acetylated/deacetylated) histones allow chromosome transcription

Acetylated (via HAT) "you put a HAT on to go to work"

Restrictive cardiomyopathy with amyloid deposition is typically (primary/secondary) amyloidosis

Primary (ex: MM)

Transmission of Giardia lamblia is via (X) in water. Diagnosis is via (Y)

``` X = cysts (fecal-oral route) Y = trophozoites/cysts in stool or antigen detection ```

Abscess with "Anchovy paste" exudate

Amebiasis (entamoeba histolytica); liver abscess

Transmission of Entamoeba histolytica is via (X) in water. What are the methods of diagnosis?

X = cysts (fecal-oral route) 1. Trophozoites with engulfed RBCs; cysts with up to 4 nuclei in stool 2. Ag detection

Flask-shaped ulcers formed on intestinal biopsy

Entamoeba histolytica

Which drugs used to eliminate E. histolyctica cysts from intestinal lumen?

Paromomycin or Iodoquinol | Otherwise, general Rx is metronidazole

Severe diarrhea in AIDs patient caused by protozoa

Cryptosporidium

Rx for cryptosporidium

Immunocompetent: Nitazoxanide Immunocompromised: Spiramycin

Toxoplasma: (X) are transmitted in cat feces. What's the treatment?

X = oocyts Sulfadiazine and pyrimethamine

Toxoplasmosis (X) brain lesions can be mistaken for (Y) and the two can be differentiated via which method?

``` X = ring-enhancing (calcified) Y = CNS lymphoma (usually solitary lesion) ``` Biopsy

Rapidly fatal meningoencephalitis from swimming in freshwater lake

Naegleria fowleri (enters via cribiform plate)

Naegeria fowleri diagnosis via (X) and Rx is (Y)

``` X = amoebas in spinal fluid Y = Amphotericin B (linked to few survivors) ```

Patient presents with cervical/axillary lymphadenopathy, somnolence, and recurring fevers. Reports recent bug bite that was very painful

``` African sleeping sickenss via: Trypanosoma brucei (CNS protozoa) - transmitted by Tsetse fly ```

Trypanosoma brucei diagnosed via (X) and treated with (Y)

``` X = trypomastigotes in blood smear Y = Suramin (for blood disease), Melarsoprol (for CNS penetration) ```

Test for G6PD deficiency before administering which anti-malarial drugs?

1. Primaquine | 2. Artesunate

Severe, irregular fever patterns and cerebral malaria

P. falciparum

(X) drug is used to treat both malaria and babesia

X = atovaquone

Malaria: mosquitos are carrying (X) form of protozoan. Enters human and matures to (Y) form in (blood/liver).

X = sporozoite Y = merozoite (contained in schizont) Liver

Malaria: (X) form of protozoan enters/infects RBCs.

X = merozoite

T/F: All merozoites in malaria come from liver

False - after initial infection of RBCs, life cycle (trophozoite to schizont to merozoite) continues in RBCs

Fever, respiratory distress (crackles, infiltrates), hemolytic anemia. Severe disease in asplenic patients. Which protozoan?

Babesia

Chagas disease caused by (X) and treated with (Y)

``` X = Trypanosoma cruzi Y = Benznidazole or nifurtimox ```

Leishmania donovani transmitted via (X) and diagnosed via (Y)

``` X = sandfly Y = presence of amastigotes in macrophages ```

Black fever, aka kala-azar, is caused by (X) and presents with which symptoms?

X = Leishmania donovani (visceral leishmaniasis) Spiking fevers, hepatosplenomegaly, pancytopenia (fatal if left untreated)

Leishmaniasis treatment:

Stibogluconate (cutaneous; ulcers) or amphotericin B (visceral)

(X) nematode can auto-infect host by ability to produce which larvae form?

X = Strongyloides stercoralis (threadworm) Rhabditiform (non-infectious; seen in host feces) lay eggs in intestine that hatch Filariform larvae (infectious; penetrate mucosa and re-enter blood)

Visceral larva migrans caused by which organism?

Toxocara canis

Skin changes, due to loss of (X), and river blindness caused by which organism?

X = elastic fibers Onchocerca volvulus

Worm crawling across eyeball

Loa loa

Liver cystic mass with eggshell calcifications

Echinococcus granulosus

Fluke egg with lateral spine

Schistosoma mansoni

Fluke egg with terminal spine

Schistosoma haematobium

Schistosoma transmitted via (X) and Clonorchis sinensis transmitted via (Y)

``` X = contact with fresh water snails Y = eating undercooked fish ```

(X) fluke/trematode causes (Y) type of gallstone

``` X = Clonorchis sinensis Y = pigmented (brown; injured hepatocytes release beta-glucoronidase which hydrolyzes BRDG so high levels of unconjugated BR) ```

Klebsiella is lactose (fermenter/non-fermenter)

Fermenter

IgA proteinase role is to allow bacteria to:

Adhere to mucosa (via cleaving IgA at hinge region and reducing effectiveness)

1 yo child with 3-5 days high fever, febrile seizures followed by maculopapular rash on trunk

Roseola infantum (by HHV-6)

Viral particle with envelope highly similar to that of nuclear cell membrane

Herpesviruses (acquire envelope via budding from nucleus)

T/F: Cryptococcus is a budding yeast

True

HIV patient with pain and itching in peri-rectal area. Single, hard mass with superficial ulceration. No hemorrhoids, no lymphadenopathy. Dx?

Squamous cell cancer (anus); linked to HPV infection

All RNA virus genomes are single stranded except:

Reovirus (dsRNA)

All DNA viruses replicate in (nucleus/cytoplasm) except:

Nucleus | Pox ("Pox out of the box")

All RNA viruses replicate in (nucleus/cytoplasm) except:

Cytoplasm Influenza and Retrovirus (HIV, HTLV)

Which DNA virus has a reverse transcriptase?

Hepadna (HBV)

Parvovirus is highly tropic for (X) cells and enters via (Y) receptor

``` X = erythroid precursors Y = P antigen (aka Globoside) ```

Number one cause of aseptic meningitis

Enteroviruses (picornavirus family)

Zika is part of which virus family?

Flaviviruses

Nearly all positive sense RNA viruses have (helical/icosahedral) capsids except:

Icosahedral Coronavirus (helicall) and HIV (complex, conical)

Nearly all negative sense RNA viruses have (helical/icosahedral) capsids except:

Helical; Delta virus (uncertain)

#1 rabies carrier in US

Bats

Eosinophilic negri bodies in neural tissue on microscopy

Rabies

Ebola is what type of virus?

Filovirus (neg sense RNA)

Ambisense virus

Arenavirus (both pos and neg sense RNA)

(Pos/neg) strand RNA viruses must always carry their own (X) polymerase

Neg | X = RNA-dep RNA pol (to make pos strand)

List the segmented RNA viruses

All neg-sense | "BOAR" (Bunyavirus, Orthomyxovirus, Arenavirus, Reovirus)

High fever, black vomit, and jaundice after mosquito bite

Yellow fever (flavivirus; aedes mosquito)

Most important global cause of infantile gastroenteritis is (X). Prevention via:

X = rotavirus Live vaccine (recommended by CDC for all infants)

(X) change in genome causes genetic shift. (Y) causes genetic drift.

``` X = reassortment (cause pandemics) Y = random mutations (cause epidemics) ```

Mumps symptoms

Parotids and testes as big as "POM-Poms" 1. Parotitis 2. Orchitis (can cause sterility) 3. Meningitis 4. Pancreatitis

Bullet-shaped virus; capsule studded with (X) spikes

X = glycoprotein Rabies

HIV: ELISA/Western blot tests are often false (pos/neg) on newborns born to infected mothers. What should be used to detect viral load in infant?

False positive (anti-gp120 Ab cross placenta) PCR

Viral hepatitis liver biopsy: granular eosinophilic "ground glass" appearance with cytotoxic T cells

HBV infection (note: cytotoxic T cells, NOT HBV, mediate damage)

Viral hepatitis liver biopsy: ballooning degeneration, spotty necrosis, monocyte infiltration, (X) bodies

X = councilman HAV infection

Prions are normally (PrPC) predominantly (alpha-helical/beta-pleated) proteins.

Alpha-helical | PrPSC transformation higher in beta-pleated sheets

Just about any healthy patient over 6 months old presenting with septic meningitis most likely has infection with (X). Which age group is the exception within this age range?

X = S. pneumo Teens (N. meningitidis is #1)

Pneumonia in an otherwise healthy neonate: top two infectious causes. What about for septic meningitis in a neonate?

1. Group B step 2. E. coli Same pathogens for meningitis!

Kids and teens presenting with pneumonia symptoms are most likely infected with:

Virus (RSV)

Adults (up until age of 40) presenting with pneumonia symptoms are most likely infected with:

Mycoplasma

Patients over 40 presenting with pneumonia symptoms are most likely infected with:

S. pneumo

Painless, beefy red genital ulcer that bleeds easily on contact

Granuloma inguinale (Klebsiella granulomatis; uncommon in US)

Which antibiotics inhibit 30S ribosome? And 50S?

"buy AT 30, CCEL (sell) at 50" 30S: Aminoglycosides, Tetracyclines 50S: Chloramphenicol, Clindamycin, Erythromycin, Linezolid

Aminoglycosides: bacteria mechanism of resistance to drug

1. Transferase enzyme (on cytoplasmic surface) catalyze transfer or acetyl, methyl, or other groups to drug (inactive it) 2. Efflux pumps

Aminoglycosides are absolutely contraindicated in patients with (X) disease

X = Myasthenia gravis (can cause neuromuscular blockade)

Dapsone mechanism of action

(Like sulfonamides) inhibits Dihydropteroate synthase (blocks PABA to DHF conversion in folate synthesis)

(X) antimicrobial drug has same target as methotrexate

X = Trimethoprim (inhibits dihydrofolate reductase)

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08a: Micro Flashcards

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