Uworld 2017 Flashcards Preview

Dr. Mel - Microbiology > Uworld 2017 > Flashcards

Flashcards in Uworld 2017 Deck (45):
1

Triad of gonorrheal infection

Arthritis
Dermatitis
Tenosynovitis
... in a sexually active person

2

2 ways to overcome bacterial production of beta-lactamase

Penicillinase-resistant penicillins (oxacillin, methicillin, nafcillin)
Beta-lactamase inhibitors (clavulanic acid, tazobactam, sulbactam)

3

2 parasites that can cause disease in RBC

Plasmodium (malaria)
Babesia (babesiosis)

4

3 organisms causing diseases by dog bites

Pasteurella
Streptococci
Staphylococci

5

2 intraintestinal infections caused by freshwater consumption

Cryptosporidiosis
Giardiasis

6

2 organisms causing infections by exposure to plants and soil

Nocardia
Sporotrichosis

7

2 fungal spore inhalation causing pulmonary infections

Histoplasmosis
Blastomycosis

8

3 bacterias treated by Streptomycin

Mycobacteria tuberculosis
Yersinia pestis
Francisella tularensis

9

4 diseases transmitted by arthropode bites

Leishmaniasis (sandfly bite)
Plasmodium/malaria (anopheles mosquitoe bite)
Chagas ds (reduviid bug bite)
Lyme ds/borrelia burgdorferi (ixodes tick bite)

10

4 causes of heterophile-antibody negative mononucleosis-like syndrome

CMV
HHV6
HIV
Toxoplasmosis

11

4 Cephalosporin-resistant organisms

Listeria monocytogenes
Atypicals (Mycoplasma, Chlamydia)
Methicillin-resistant staphylococcus
Enterococci

12

Botulism

Infant B: honey, spore ingestion, moderate to severe (constipation, mild weakness, lethargy, poor feeding to floppy baby)
Adult B: canned food, preformed toxin ingestion, very severe

13

Gastroenteritis acquired from domestic animals or contaminated food

Campylobacter jejuni
From cattle, chickens, dogs
Inflammatory diarrhea, fever, abdo pain, tenesmus
Ass w/ Guillain-Barré sd

14

Listeria monocytogenes

Very narrow zone beta-hemolysis on blood agar
Immotile at 37*
Tumbling motility at 22*
Cultured at 4*
Infection when weak cell-mediated immunity (neonates-3mo, ID)

15

EHEC infection

No invasion of mucosa
Shiga-like toxin that inhibits protein synthesis in colonic mucosa + renal endoth cells (inactivats 60S ribosome)
No sorbitol fermentation
No production of glucuronidase

16

Influenza epidemics + pandemics

By genetic reassortment of RNA segments coding for hemagglutinin or neuraminidase proteins
Major antigenic shifts

17

E coli virulence

Neonatal meningitis: K1 capsular antigen (bact survive in blood + cause meningitis)
UTI: fimbriae (adhesive proteins)

18

Predisposition to high bacteremia/sepsis

By indwelling central catheters
Suspect cath-related inf in hospitalized ptts w/ new fever or bacteremia

19

Resistance of Enterococci to Aminoglycosides

Produce aminoglycoside-modifying enzymes that transfer chemical groups (acetyl, ...) to aminoglycoside molecule
Impair AB binding to ribosomal subunits

20

Cells recruted when superantigens (TSST)

Nonspecific, widespread activation of T cells (IL2)
Macrophages (IL1, TNF)

21

Risk of HCC in HBV + HCV

HBV: risk always elevated bcz HBV DNA persistent in genome
HCV: lacks reverse transcriptase, no integration in genome, risk diminishes after Ab and viral replication stops

22

Reactivation of latent EBV in HIV+

Increased incidence of EBV-induced lymphoproliferative disorders (malignant B-lymphocytes, ...)

23

Meningococcus attachment to host cell

By pilli
On mucosal epith of nasopharynx

24

Vertical transmission of Hepatitis B in pregnant women

In active hepatitis B inf
HBeAg increases the risk
Newborns of mothers w/ active hepB: passively immunized at birth w/ HBIg then recombinent HBV vaccine

25

MOA of adverse effects of Amphotericin B

Antifungal effect: by binding to ergosterol in fungal cell membrane
Adv effects: by binding cholesterol in human cells
Nephrotoxicity
Hypokalemia
Hypomagnesemia

26

Corynebacterium diphtheriae

Cultured on cysteine-tellurite agar: black colonies
Bact produce intracellular phosphate granules (metachromatic granules): on methylene blue staining

27

Septic shock

From release of endotoxins (in outer membrane of G-)
LPS: O antigen, core polysacch, lipid A
Lipid A: toxic, activation of macrophages (IL1, TNFa)

28

AB exotoxin of Diphtheria toxin

Ribosylates + inactivates EF-2
Inhibits prot synthesis then cell death

29

Haemophilus influenzae type b vaccine

Reduced incidence of meningitis, pneumonia, bacteremia, epiglottitis

30

Vitamin A in measles infection

Reduce comorbidities
Recovery time
Length of hospitalization

31

Side effects of protease inhibitors

Hyperglycemia
Lipodystrophy
Drug-drug interactions (by inhib of CYP450)

32

Malignancies ass w/ EBV

Burkitt lymphoma
Nasopharyngeal carcinoma

33

Diagnosis of Genital herpes simplex virus infection

PCR
Direct fluorescence Ab testing
Viral culture
Tzank smear

34

Neonatal tetanus

Prevented by hygenic delivery + umbilical cord care + immunization of women
Passive imm: transplacental IgG
Active imm: around age 2 months

35

EBV in malignancies

In 50% of systemic B-cell lymphomas, primary CNS lymphomas in HIV+
Burkitt lymphoma if high mitotic index

36

Defense against Candida

Local: T cells; so common on HIV
Systemic: neutrophils; so common in neutropenic ptt

37

Zidovudine

NRTI: binds reverse transcriptase
Incorporated into viral genome as thymidine analog
No 3’-5’ phosphodiester bond formation

38

Foscarnet

Pyrophosphate analog
Do not require intracellular activation
Bind + inhibit: DNA polymerase in herpes virus and reverse transcriptase in HIV

39

Abacavir hypersensitivity reaction (AHR)

2-8% of ptts
Ass w/ HLA-B*57:01 allele
HS type IV
Fever, malaise, GI sympt, delayed rash

40

Mycobacterial resistance to Streptomycin, Isoniazid, Rifampin

Streptomycin inhibits prot synthesis by inactivating 30S
Decreased activity of bact catalase-peroxidase: mycobacterial resist to isoniazid
Alteration of enzymes for RNA synthesis: resist to Rifampin

41

Ttt of Lyme ds

Tetracyclines
But CI in pregnancy (fetal tooth discoloration) so Amoxicillin

42

Invasive pneumococcal ds

Elderly + young children
Vaccination (conjugate V)
Pneumo polysaccharide V (unconjugated): relative T-cell dep response
Pneumo conjugate V (polysacc + prot Ag): robust T-cell dep resp

43

Histoplasma capsulatum in immunocompromed ptt

Survive intracell in macrophages
Disseminated mycosis
Fever, weight loss, painful oral ulcers, lymphad, HSM

44

Mycobacterium avium complex (MAC)

Disseminated ds in HIV+
If CD4<50 give prophylactic azithromycin to prevent MAC

45

Ether + organic solvents

Dissolve lipid bilayer of outer viral envelope