Uworld 2017 Flashcards by Melissa Khalil

Triad of gonorrheal infection

Arthritis
Dermatitis
Tenosynovitis
… in a sexually active person

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2 ways to overcome bacterial production of beta-lactamase

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

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2 parasites that can cause disease in RBC

Plasmodium (malaria)

Babesia (babesiosis)

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3 organisms causing diseases by dog bites

Pasteurella
Streptococci
Staphylococci

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2 intraintestinal infections caused by freshwater consumption

Cryptosporidiosis

Giardiasis

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2 organisms causing infections by exposure to plants and soil

Nocardia

Sporotrichosis

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2 fungal spore inhalation causing pulmonary infections

Histoplasmosis

Blastomycosis

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3 bacterias treated by Streptomycin

Mycobacteria tuberculosis
Yersinia pestis
Francisella tularensis

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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)

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4 causes of heterophile-antibody negative mononucleosis-like syndrome

CMV
HHV6
HIV
Toxoplasmosis

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4 Cephalosporin-resistant organisms

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

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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

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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

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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)

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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

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Influenza epidemics + pandemics

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

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E coli virulence

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

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Predisposition to high bacteremia/sepsis

By indwelling central catheters

Suspect cath-related inf in hospitalized ptts w/ new fever or bacteremia

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Resistance of Enterococci to Aminoglycosides

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

Cells recruted when superantigens (TSST)

Nonspecific, widespread activation of T cells (IL2)

Macrophages (IL1, TNF)

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

Reactivation of latent EBV in HIV+

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

Meningococcus attachment to host cell

By pilli

On mucosal epith of nasopharynx

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

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

Corynebacterium diphtheriae

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

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)

AB exotoxin of Diphtheria toxin

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

Haemophilus influenzae type b vaccine

Reduced incidence of meningitis, pneumonia, bacteremia, epiglottitis

Vitamin A in measles infection

Reduce comorbidities Recovery time Length of hospitalization

Side effects of protease inhibitors

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

Malignancies ass w/ EBV

Burkitt lymphoma | Nasopharyngeal carcinoma

Diagnosis of Genital herpes simplex virus infection

PCR Direct fluorescence Ab testing Viral culture Tzank smear

Neonatal tetanus

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

EBV in malignancies

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

Defense against Candida

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

Zidovudine

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

Foscarnet

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

Abacavir hypersensitivity reaction (AHR)

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

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

Ttt of Lyme ds

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

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

Histoplasma capsulatum in immunocompromed ptt

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

Mycobacterium avium complex (MAC)

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

Ether + organic solvents

Dissolve lipid bilayer of outer viral envelope