Uworld 2017 Flashcards
Triad of gonorrheal infection
Arthritis
Dermatitis
Tenosynovitis
… in a sexually active person
2 ways to overcome bacterial production of beta-lactamase
Penicillinase-resistant penicillins (oxacillin, methicillin, nafcillin)
Beta-lactamase inhibitors (clavulanic acid, tazobactam, sulbactam)
2 parasites that can cause disease in RBC
Plasmodium (malaria)
Babesia (babesiosis)
3 organisms causing diseases by dog bites
Pasteurella
Streptococci
Staphylococci
2 intraintestinal infections caused by freshwater consumption
Cryptosporidiosis
Giardiasis
2 organisms causing infections by exposure to plants and soil
Nocardia
Sporotrichosis
2 fungal spore inhalation causing pulmonary infections
Histoplasmosis
Blastomycosis
3 bacterias treated by Streptomycin
Mycobacteria tuberculosis
Yersinia pestis
Francisella tularensis
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)
4 causes of heterophile-antibody negative mononucleosis-like syndrome
CMV
HHV6
HIV
Toxoplasmosis
4 Cephalosporin-resistant organisms
Listeria monocytogenes
Atypicals (Mycoplasma, Chlamydia)
Methicillin-resistant staphylococcus
Enterococci
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
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
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)
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
Influenza epidemics + pandemics
By genetic reassortment of RNA segments coding for hemagglutinin or neuraminidase proteins
Major antigenic shifts
E coli virulence
Neonatal meningitis: K1 capsular antigen (bact survive in blood + cause meningitis)
UTI: fimbriae (adhesive proteins)
Predisposition to high bacteremia/sepsis
By indwelling central catheters
Suspect cath-related inf in hospitalized ptts w/ new fever or bacteremia
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
