USMLE MICRO 2 Flashcards

Terms Definitions
No envelope
nonsurgical antimicrobial prophylaxis-history of recurrent UTIs
Snails are host
Toxicity of foscarnet
Diarrhea post travel
Tx for Babesia
Quinine, clindamycin
Enveloped, SS +, Icosahedral
Major clinical manifestations: Deafness Cataracts Heart defects (PDA, pulmonary artery stenosis) Microcephaly Mental retardation Blueberry muffin baby due to rash Which ToRCHeS organism is this?
Mononucleosis: Mononucleosis is caused by _______
Sexually transmitted diseases: Urethritis, cervicitis, conjunctivities, Reiter's syndrome, and PID are features of what diesease?
Treatment for superficial candida infection
Protozoa: Bloating, flatulence, foul-smelling, fatty diarrhea
Giardia lamblia
Parasite: Hematuria, bladder CA
Schistosoma haematobium
Tricky T's: Trichomonas vaginalis
Protozoan, STD.
Virology: Which SS-linear(-) DNA virus is responsible for "slapped cheeks" rash?
Gram-negative Lab Algorithm: Which are oxidase-positive?
Stains: PAS stains ---
glycogen, mucopolysaccharides
what nonmotile gram negative, non-lactose fermenting facultative anaerobic rod uses the human colon as its only reservoir and is transmitted by fecal oral spread
Common causes of osteomyelitis in:diabetics and drug addicts
Pseudomonas aeruginosa
HIV - Interstitial pneumonia; biopsy reveals cells with intranuclear and cytoplasmic inclusion bodies
High fever, black vomitus, jaundice
Yellow fever
Silver stain
used to visualize: fungi, Legionella
Toxicity of isoniazid (INH)
Neurotoxicity, hepatotoxicity. Pyridoxine (Vitamin B6) can prevent neurotoxicity. (INH I njures N eurons and H epatocytes)
Snails are host; Cercariae penetrate skin of humans, causes granulomas, fibrosis, and inflammation of the spleen and liver. Chronic infxn w/ S. haematobium can lead to squamous cell carcinoma of the bladder. Tx: Praziquantel.
Tricky T's: Toxoplasma
protozoan, a TORCH infxn.
Clinical use of polymyxins
resistant gram(-) infxns
Neisseria meningitidis (Meningococci)
Polysaccharide capsule Maltose fermentation (MeninGococci ferments Maltose and Glucose) Vaccine available Transmitted by respiratory and oral secretions Causes meningococcemia and meningitis, Waterhouse-Friderichsen syndrome
Osteomyelitis: What lab test is elevated in osteomyelitis?
Gram-negative Lab Algorithm: What are the gram-negative cocci?
Nosocomial infections: What is the most likely pathogen when a water source (water aerosols) is involved?
which organism causes multiple infections by antigen switching
borrelia recurrentis
why to avoid this drug during pregnancy:griseofulvin (antifungal)
Common causes of osteomyelitis in:most people
S. aureus
HIV - Chronic watery diarrhea; acid-fast cysts seen in stool
Cryptosporidium spp.
Ingestion of larvae encysted in undercooked pork. Cysticercosis and neurocysticercosis, mass lesions in brain.
Taenid solium
Neisseria (generally)
Both are: Gram(-) cocci Ferment glucose and produce IgA proteases. <img src="Neisseria gonorrhoeae.JPG" />
"Lots of spots": Varicella
Herpesvirus; chickenpox and zoster.
The following is the most common mechanism of resistance for what drug? methylation of rRNA near erythromycin's ribosome-binding site
Mechanism of griseofulvin
Interferes w/ microtubule fxn; disrupts mitosis. Deposits keratin-containing tissues (e.g., nails). [below, bottom/right] <img src="192a - Antifungal therapy.JPG" />
Haemophilus influenzae vaccine
Contains type B capsular polysaccharide conjugated to diphtheria toxoid or other protein to improve immune system recognition of polysaccharide and promote class switching. Given btw 2 and 18 months of age.
Toxins: Enterotoxins
Organism, toxin function: S. aureus (and others) Cause food poisoning
Branching Filamentous bacteria (G+)
Actinomyces Nocardia (weakly acid-fast)
Hepatitis serologic markers: If I got a Hepatitis B vaccine (no infection), for what Ab would I have a positive serology?
More virology: The only DNA viruses that does not replicate in the nucleus is:
UTI Bugs: Leading cause of UTIs
Escherichia coli
Hepatitis transmission: Name the type of nucleic acid and the virus type for the following hepatitis viruses: Hepatitis B
DNA hepadnavirus
Haemophilus Influenzae: Use ___ to treat H. influenzae meningitis and ___ for prophylaxis of close contacts.
Ceftriaxone, rifampin
Special Culture Requirements: Pink colonies on MacConkey's agar are ---
Lactose-fermenting enterics (Klebsiella, Eschericihia, or Enterobacter
HIV capsid, core nucleocapsid, and matrix proteins are products of what structural gene
gag gene
what virus is assoc w/ norwalk agent
what bacterium is rsponsible for woolsorter's disease
bacillus anthracis
Three etio of common cold
Rhino, corona, adeno
decr uptake or incr transport out of cell
Larvae in soil penetrate skin; lung sx; intestinal infection; causes vomiting, diarrhea, and anemia, abdominal bloating, weight loss.
Strongyloides stercoralis
Trematodes (flukes): Paragonimus wetermani Transmission/dz? Tx?
Undercooked crab meat; causes inflammation and secondary bacterial infxn of the lung. Tx: Praziquantel.
Tricky T's: Typanosoma
Protozoan, causes Chagas' dz (T. cruzi) or African sleeping sickness.
Yersinina pestis Causes? Transmission?
Causes: Plague Transmission: Flea bite; rodents (esp. prairie dogs)
Mechanism of foscarnet
Viral DNA polymerase inhibitor that binds to the pyrophosphate-binding site of the enzyme. Does not require activation by viral kinase. (FOS carnet = pyroFOS phate analog) [would fit into DNA synthesis on bottom/right] <img src="193a - Antiviral sites of action.JPG" />
Toxicity of Amphotericin B
Fever/chills (shake and bake), hypotension, nephrotoxicity, arrhythmias, anemia, IV phlebitis (amphotericin = amphoterrible). Hydration reduces nephrotoxicity. Liposomal amphotericin reduces toxicity.
STD's: Secondary syphilis Organism? Clinical features?
Treponema pallidum Fever, lymphadenopathy, skin rashes, condylomata lata
STD's: Primary syphilis Organism? Clinical features?
Treponema pallidum Painless chancre
Media/Special culture requirements for: B. pertussis
Bordet-Gengou (potato) agar (Media used for isolation)
Bacterial Structures: Peptidoglycan
Gives rigid support, protects against osmotic pressure;
Sugar backbone w/ cross-linked peptide side chains. (function; chemical composition)
Name the diseases caused by the following Herpesviridae:: HSV-1
Gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, herpes labialitis
Hepatitis transmission: Mode of transmission: Hepatitis C
blood (IV drug users)
Name the dominant normal flora in each of these areas:: nose
Staph aureus
Spores: Bacterial: What disinfecting procedure kills spores?
Autoclaving (ex/ surgical equipment)
Nosocomial infections: What pathogen is often found on respiratory therapy equiptment?
Pseudomonas aeruginosa (AIRuginosa when AIR or burns are involved?
what Ab is an indication of recurrent disease for hepatitis
what enzyme does HIV use to integrate the proviral dsDNA into the host
Hepatitis type where there is AVERSION to smoking
Hep A
Eggs in dog feces when ingested can cause cysts in liver; causes anaphylaxis if Ags are released from cysts (surgeons inject ethanol before removal to neutralize Ags).
Echinococcus granulosus
HIV's genome
Diploid (2 molecules of RNA, but not dsRNA).
What HBV Ag/Ab's would show up in immunized individuals?
HBsAb only.
Nosocomial pathogen: HBV Risk factor?
Work in renal dialysis unit
Bacterial Structures: Periplasm
Space btw the cytoplasmic membrane and the outer membrane in G- bacteria; Contains may hydrolytic enzymes, including beta-lactamases (function; chemical composition)
Clinical use of aztreonam
Gram(-) rods - Klebsiella spp., Pseudomonas spp., Serratia spp. No activity against gram(+)'s or anaerobes. For penicillin-allergic pts and those w/ renal insufficiency who cannot tolerate aminoglycosides.
Clinical use of foscarnet
CMV retinitis in immunocompromised pts when ganciclovir fails; acyclovir-resistant HSV.
Mucor and Rhizopus species
Cause mucormycosis. Mold w/ irregular nonseptate hyphae branching at wide angles (> 90 degrees). <img src="159e - Mucor.JPG" />
Pneumocystis jiroveci (formerly carinii) Dx?
Diffuse, bilateral CXR appearance. Dx by lung biopsy or lavage: identified by methenamine silver stain of lung tissue.
Mucormycosis epidemiology/pathogenesis
(caused by Muro and Rhizopus spp.) Dz most likely in ketoacidotic diabetic and leukemic pts. Fungi also proliferate in the walls of blood vessels and cause infarction and necrosis of distal tissue. Rhinocerebral, frontal lobe abscesses.
what bug is carried by pets (puppies) and can mimic appendicitis or Crohn's
yersinia enterocolitica
UTI Bugs: What do E. coli colonies show on EMB agar?
metallic sheen
Stains: Stain used to diagnose Whipple's disease
PAS (Periodic Acid Schiff)
Pseudomonas Aerugenosa: What is the treatment for P. aeruginosa
Aminoglycoside plus extended-spectrum penicillin (piperacillin, ticarcillin)
Pelvic inflammatory disease: What are some of the manifestations of PID?
Purulent cervical discharge, salpingitis, endometriosis, and hydrosalpinx
what is the only DNA virus that is not icosahedral
Rash begins on palm and spreads to trunk
Rickettsia (RMSF)
Common causes of meningitis in:60yr +
S. pneumoniae, Gram-neg rods, Listeria
Rifampin's 4 R's
R NA polymerase inhibitor R evs up microsomal P-450 R ed/orange body fluids R apid resistance if used alone
STD's: Genital herpes Organism? Clinical features?
HSV-2 Painful penile, vulvar, or cervical ulcers; can cause systemic Sx such as: fever, HA, myalgia
Protozoa: Trypanosoma: T. gambiense T. rhodesiense Dz? Transmission? Dx? Tx?
Cause African sleeping sickness: enlarged LNs, recurring fever (due to antigenic variation), somnolence, coma Transmitted by Tsetse fly Dx via blood smear Tx w/ SUR amin for blood-borne dz, or MELA rsoprol for CNS penetration (it SUR e is nice to sleep; MELA tonin helps w/ sleep)
Culturing H. influenzae
Chocalate agar w/ factors V (NAD) and X (hematin) When a child has 'flu'*, mom goes to the five (V ) and dime (X ) store to buy some chocolate [*remember that H. influenzae does not cause flu]
Food poisoning from: Clostridium botulinum
Food: improperly canned foods (bulging cans)
Food poisoning from: Bacillus cereus
Food: reheated rice. (Food poisoning from reheated rice? Be Serious! [B. cereus])
Secreted by S. pneumoniae, H. influenzae, and Neisseria to prevent phagocytosis
IgA protease Who secretes it?
Common causes of pneumonia in adults (18-40yrs)
Mycoplasma Chlamydia pneumoniae Streptococcus pneumoniae
what is the Weil-Felix reaction
rxn to assay for antiricketsial antibodies which cross react with proteus (but negative with Q fever - coxiella)
Rabies virus: Rabies -- most common sources in US
bat, raccoon, skunk (>dog)
Gram-positive Lab Algorithm: When would you do the optochin test?
When you have alpha hemolytic strep
name the plasmodium spp...1. no persistent liver stage or relapse; blood smear shows multiple ring forms and crescent-shaped gametes; irregular febrile pattern; assoc w/ cerebral malaria2. no persistent liver stage or relapse; blood smear sho
1. plasmodium falciparum2. plasmodium malariae3. plasmodium ovale4. plasmodium vivax
UTI, hospitalized pt w/ urinary catheter
Klebsiella pneu / E. faecalis
Anthrax via inhalation of spores
Flulike Sx that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, and shock
Antibiotics to avoid in pregnancy (list -- what are they, and why for each one?)
S ulfonamides -- kernicterus
A minoglycosides -- ototoxicity
F luoroquinolones -- cartilage damage
E rythromycin -- acute cholestatic hepatitis in mom (and clarythromycin -- embryotoxic)
M etronidazole -- mutagenesis
T etracyclines -- discolored teeth, inhibition of bone growth R ibavirin (antiviral) -- teratogenic
G riseofulvin (antifungal) -- teratogenic
C hloramphenicol -- gray baby
(SAFE M oms T ake R eally G ood C are.)
Bloody diarrhea O157:H7 Can cause HUS Makes Shiga-like toxin [bugs that cause diarrhea: type of diarrhea and findings]
Bugs that cause diarrhea: Enterohemorrhagic E. coli (EHEC)
What is salpingitis a risk factor for?
Ectopic pregnancy Infertility Chronic pelvic pain Adhesions
what group are aminoglycosides ineffective against
anaerobes - bc they require O2 dependent uptake
Hepatitis serologic markers: If I recently had a Hepatitis B infection, for what Ab would I have a positive serology
HBsAb and HBcAb (positive during window period)
Haemophilus Influenzae: Culture on ___ agar requires ___ and ___
Chocolate agar, Factor V (NAD), X (hematin)
What causes this type of red rash in childhood:vesicular rash on palms and soles, ulcers in oral mucosa
Cocksackievirus type A (Hand-foot-mouth disease)
Organisms causing rash on palms and soles
Coxackie A, syphilis, Rocky Mountain spotted fever
3 Most common causes of ambulatory UTI
1.) E. coli (50-80%) 2.) Staphylococcus saprophyticus (10-30%): 2nd most common cause of UTI in young, sexually active, ambulatory women 3.) Klebsiella (8-10%)
what protozoa shows a maltese cross and ring formation
babesia (fever and hemolytic anemia)- tx clindamycin
Bacterial Growth Curve: Describe the four phases of bacterial growth.
1) Lag phase of metabolic activity without division. 2) Log phase of rapid cell division. 3) Stationary phase in which nutrient depletion slows growth. 4) Death due to prolonged nutrient depletion and buildup of waste products.
what is the only trematode that is not hermaphroditic
schistosoma have boys and girls
5 bacterial toxins encoded in a lysogenic phage
ABCDE ShigA -like toxin B otulinum toxin (certain strains) C holera toxin D iphtheria toxin E rythrogenic toxin of Streptococcus pyogenes
HIV diagnosis: How do I make a diagnosis of HIV?
ELISA --> confirmed by Western blot
CSF findings in meningitis: You do a quick smear of the spinal tap under the microscope and see increased polys. What type of infectious agent does this suggest?
bacterial. In fungal, TB, and viral, you see increased lymphocytes.
nonsurgical antimicrobial prophylaxis-gonorrhea
Tx of Schistosoma
River blindness
Onchocerca volvulus
Visualizing Mycobacteria
Acid-fast stain
Mechansm:vancomycin, bacitracin
blocks peptidoglycan synthesis
Tx for Diphyllobothrium latum
Enveloped, SS+, linear, icosahedral
Dimorphic fungi
(Histoplasmosis, Blastomycosis, Coccidioidomycosis, and Paracoccidioidomycosis) Mold in soil (@ lower temps) and yeast in tissue (@higher/body temp: 37C), except coccidioidomycosis, which is a spherule in tissue. Cold = Mold, Heat = Yeast All can cause pneumonia and can disseminate. Tx: fluconazole or ketoconazole for local infxn, amphotericin B for systemic infxn. Systemic mycoses can mimic TB (granuloma formation)
Macrolides (list)
Erythromycin, azithromycin, clarithromycin
HBV Jaundice Disease?
Hepatitis B
Hematuria, bladder cancer
Schistosoma haematobium
Legionella Pneumophilia: T/F: Legionella pneumophilia is transmitted through environmental water source habitat.
Copious watery diarrhea
V. cholera
Treatment for Haemophilus influenzae meningitis
Ocular problems (cataracts, retinopathy, micropthalmos, glaucoma), cardiovascular problems (PDA, VSD, pulmonary stenosis), deafness, thrombocytopenia purpura, hepatosplenomegaly, CNS problems, bony lesions
Congenital rubella
Enveloped. ss(-)circular RNA, 2 segments. Helical capsid. LCMV -- lymphocyticc choriomeningitis virus. Lassa fever encephalitis -- spread by mice.
No envelope. ss(+)RNA, linear. Icosahedral capsid. Norwalk virus -- viral gastroenteritis.
Transmitted by arthropods (mosquitoes, ticks). Classic examples: dengue fever (aka break-bone fever) and yellow fever . A variant of dengue fever in SE Asia is hemorrhagic shock syndrome . ARBO virus = AR thropod-BO rne virus Includes some members of F lavivirus, T ogavirus, and B unyavirus: F ever T ransmitted by B ites
RNA viruses: Poliovirus, Echovirus,Rhinovirus, Coxsackievirus, and HAV are all members of which viral family?
Picornaviruses ("PERCH")
Special Culture Requirements: Lowenstein-Jensen agar for growing ---
Mycobacterium tuberculosis
Sexually transmitted diseases: What serotypes of Chlamydia trachomatis cause Lymphogranuloma venereum?
What branching filamentous bacteria affects the respiratory system of immunocompetent pts
blocks protein synthesis at 50S ribosomal subunit
HIV - Non-hodgkin's lymphoma (large cell type); often on oropharynx (Waldeyer's ring)
All contain surface F "fusion" protein
Streptococcus agalactiae (GBS)
Bacitracin resistant Beta-hemolytic Causes: Pneumonia meningitis Sepsis (mainly in babies) B is for Babies!
Common cause of pneumonia w/ aspiration
Clostridium botulinum
produces preformed, heat-labile toxin that inhibits ACh release at the NMJ, causing botulism (flaccid paralysis). In adults, dz is caused by ingestion of preformed toxin. In babies, ingestion of bacterial spores in honey causes dz (floppy baby syndrome). BOTulinum is from bad BOTtles of food and honey.
Treponemal diseases
Treponemes are spirochetes. Treponema pallidum: Causes syphilis Treponema pertenue: Causes yaws; Infxn of skin, bone, and joints --> healing w/ keloids --> severe limb deformities Dz of the tropics. Not an STD, but VDRL positive.
HIV immunity: Persons with ______________ have a rapid progression to AIDS
CXCR1 mutation
Name diarrheal organism associated with the following:: Transmitted through pet feces (puppies), bloody diarrhea
Yersenia enterocolitica
Nosocomial infections: Which pathogen would most associated with hyperalimentation (total parenteral nutrition)
Candida albicans
what facultative intracellular fungus is assoc w/ hepatosplenomegaly
histoplasma capsulatum
Most likely pathogen in HIV+ adult: retinitis, cotton-wool spots on funduscopic exam
Shiga toxin
Cleaves host cell rRNA (inactivates 60S ribosome); enhances cytokine release, causing HUS.
Enveloped, SS -, circular, 3 segments, helical
Prophylaxis in close contacts of pts w/Haemophilus influenzae meningitis
Risk factor for a nosocomial pathogen: Work in renal dialysis unit What is the pathogen?
Bug hints (if all else fails):Traumatic open wound What is the bug?
Clostridium perfringens
Features: Leading cause of UTI. Colonies show metallic sheen on EMB agar. Which UTI bug is this?
Escherichia coli
Mechanism of aztreonam
A monobactam resistant to beta-lactamases. Inhibits cell wall synthesis (binds to PBP3). Synergistic w/ aminoglycosides. No cross-allergenicity w/ penicillins.
Generalized transduction
Lytic phage infects bacterium, leading to cleavage of bacterial DNA and synthesis of viral proteins. Parts of bacterial chromosomal DNA may become packaged in viral capsid. Phage infects another bacterium, transferring these genes.
Quellung (+) Bacteria
Encapsulated (Some Nasties Have Kapsules) Streptococcus pneumoniae Neisseria meningitidis Haemophilus influenzae (esp. type B) Klebsiella pneumoniae Polysaccharide capsule is an antiphagocytic virulence factor for above bacteria.
Tricky T's: Typhus
caused by bacteria Rickettsia prowazekii (epidemic), Rickettsia typhi (endemic), and Rickettsia tsutsugamushi (scrub typhus)
what is used to tx anaerobic infections below the diaphragm (and antiprotazoal)
Common causes of pneumonia: The same patient also aspirated some peas prior to getting sick. What organisms do you add to your list?
Viral Pathogens: RNA nucleocapsid enteroviruses include which pathogens?
poliovirus, coxsackievirus, echovirus, HAV
Viridans Strep: S. sanguis causes ___
bacterial endocarditis
Gram Stain Limitations: --- stain with silver
Legionella pneumophila
what small gram pos, non-spore forming rod is a faultative intracellular parasite that grows in the cold and is assoc w/ unpasteurized milk products
listeria monocytogenes
what are the three Cs of measles
what is the most likely causitive organism for a patient with folliculitis after spending time in a hot tub
Most highly resistant bug causing subacute endocarditis and hospital catheter acquired UTI
E. faecalis
Fungal infection with rhinocerebral, frontal lobe abscesses
Mucor or Rhizopus spp.
Ingestion of larvae in raw freshwater fish. Causes vitamin B12 deficiency, resulting in anemia. Tx: Praziquantel.
Diphyllobothyrium latum
Clostridium dificile
Produces a cytotoxin, an exotoxin that kills enterocytes, causing pseudomembranous colitis. Often 2' to ABX use, especially clindamycin or ampicillin. DI fficile causes DI arrhea Tx: metronidazole
Clinical use of ganciclovir
CMV, especially in immunocompromised pts
Clinical use of azoles
Systemic mycoses. Fluconazole for cyptococcal meningitis in AIDS pts (b/c it can cross the BBB) and candidal infxns of all types (i.e., yeast infxns). Ketoconazole for Balstomyces, Coccidioides, Histoplasma, Candida albicans, hypercortisolism. Clotrimazole and miconazole for topical fungal infxns.
Mechanism of metronidazole
Forms toxic metabolites in the bacterial cell that damage DNA. Bactericidal, antiprotozoal.
Antimycobacterial drugs: for M. avium-intracellulare
Prophylaxis: Azithromycin Tx: Azithromycin Rifampin Ethambutol Streptomycin
RNA enveloped viruses (list)
Influenza virus, parainfluenza virus, RSV, measles virus, mumps virus, rubella virus, rabies virus, HTLV, HIV
Dominant normal flora of the: Oropharynx
Viridans group streptococci
Mumps virus
A paramyxovirus. Sx: P arotitis O rchitis (inflammation of the testes)* [aseptic] M eningitis Mumps makes your parotid glands and testes as big as POM -poms *Can cause sterility (especially after puberty)
Name the routes of transmission for the following Herpesviridae:: VSV
respiratory secretions
HIV immunity: What % of US caucasians have a slower course of HIV infection because of heterozygosity for the above allele?
Spores: Bacterial: T or F: Spores are highly resistant to destruction by heat and chemicals
Anthrax: Anthrax is caused by ___ (bacteria)
Bacillus anthracis
which dimorphic fungus is found as hyphae with nondescript conidia in rotting wood in the upper great lakes, ohio, mississippi, eastern seaboard of the US and southern canada
blastomyces dermatitidis
what non spore forming gram pos aerobic rod produces bull neck, sore throat w/ pseudomembranes, myocarditis, and sometimes respiratory obstructions
corynebacterium diphtheria
t or fall proteus spp are urease pos
Common causes of osteomyelitis in:sexually active people
N. gonorrhoeae (rare), septic arthritis more common
Viral family: Bunyaviruses Envelope? RNA structure? Capsid symmetry? Medical importance?
Enveloped. ss(-)circular RNA, 3 segments. Helical capsid. California encephalitis* Sandflly/Rift Valley fevers Crimean-Congo hemorrhagic fever* Hantavirus -- hemorrhagic fever, pneumonia (*=arbovirus)
STD's: AIDS Organism? Clinical features?
HIV Opportunistic infxns, Kaposi's sarcoma, lymphoma
Clinical use of terbinafine
Used to Tx dermatophytoses (especially onychomycosis)
Common cause of pneumonia in alcoholics/IV drug users
Streptococcus pneumoniae Klebsiella Staphylococcus
Mechanism of ganciclovir
5'-monophosphate formed by a CMV viral kinase or HSV/VZV thymidine kinase. Guanosine analog. Triphosphate formed by cellular kinases. Preferentially inhibits viral DNA polymerase. [fits in w/ NA analogs below, bottom/right] <img src="193a - Antiviral sites of action.JPG" />
Protozoa: Trypanosoma cruzi Dz? Transmission? Dx? Tx?
Causes Chagas' dz (dilated cardiomyopathy, megacolon, megaesophagus); predominantly in South America Transmitted by Reduviid bug (kissing bug) Dx by blood smear Tx w/ Nifurtimox <img src="162a - Trypanosoma cruzi.JPG" />
Endotoxin and Macrophages
Activates Macs: IL-1 causes fever TNF causes fever, hemorrhagic tissue necrosis NO causes hypotension (shock) <img src="144a - endotoxins.JPG" />
what are G+ cocci that are catalase - in clusters
Urinary tract infections: What are symptoms of a UTI?
dysuria, frequency, urgency, suprapubic pain
Virology: All DNA viruses are linear except these two:
papoviruses, hepadnavirus (circular)
Naegleria: How is it transmitted?
Swimming in fresh water lakes
Gram-positive Lab Algorithm: What are the 4 types of gram-postive rods?
Corynebacterium, Listeria, Bacillus, Clostridium
Helicobacter Pylori: What is a test for H. pylori?
Urease breath test
Pelvic inflammatory disease: What are the top bugs that cause PID?
Chlamydia trachomatis (subacute, often undiagnosed), Neisseria gonorrheae (acute, high fever)
what is the first Ag seen in an individual w/ hep
What is the MC late manifestation of Lyme dz
Joint involvement
What organism(s) cause(s) pneumonia in:adults (40-65yr)
S. pneumoniae, H. flu, anaerobes, viruses, mycoplasma
Protein synthesis inhibitors: 30S inhibitors
A = A minoglycosides (streptomycin, gentamycin, tobramycin, amikacin) [bacteriostatic] T = T etracyclines [bacteriostatic] (But AT 30 , CCELL (sell) at 50) [*note different specific sites of action of Aminoglycosides and TCNs below] <img src="187a - Protein synthesis inhibitors.JPG" />
Bacteria w/ unusual cell membranes/walls
Mycoplasma: contain sterols and have no cell wall Mycobacteria: Contain mycolic acid. High lipid content.
Mechanism of macrolides (Erythromycin, azithromycin, clarithromycin)
Inhibit protein synthesis by blocking translocation; bind to the 23S rRNA of the 50S ribosomal subunit. Bacteriostatic.
Both HBV and HCV...
... predispose pt to chronic active hepatitis, cirrhosis, and hepatocellular carcinoma.
Parasite hints - Finding: Diphyllobothrium latum
Parasite hints - organism: B12 deficiency
Tzanck test
A smear of an opened skin vesicle to detect multinucleated giant cells. Used to assay for HSV-1, HSV-2, and VZV. Tzanck heavens I don't have herpes!
Clinical use of flucytosine
Used in systemic fungal infxns (e.g., Candida, Cryptococcus) in combination w/ amphotericin B
Yellow fever: Yellow fever -- histology
Liver: councilman bodies (acidophilic inclusions)
Main Exotoxin and Endotoxin Features: What are exotoxins and endotoxin chemically?
Exotoxins are polypeptides, while endotoxins are lipopolysaccharides.
Viridans Strep: How do you differentiate viridans strep from S. pneumoniae in the laboratory?
Both are alpha-hemolytic, but viridans strep is resistant to optochin (live in the mouth, not afraid of-the-chin)
Bacterial Strucutre & Cell Walls: What are spores made of and what do they do?
Keratin-like coat, dipicolinic acid. Provide resistanceto dehydration, heat and chemicals
Salmonella Vs. Shigella: More virulent
Shigella (10e1 innocumlum compared to 10e5 innoculum for Salmonella)
t or fall spore formers are gram pos
t(bacillus and clostridium)
t or finterferons are eukaryotic proteins that inhibit viral replication by being virus specific
falseinterferons are produced by virally infected cells to inhibit viral replication via RNA endonucleases. They do not act directly on the virus, nor ar they virus specific
Common causes of meningitis in:Newborn (0-6 mo)
Group B strep, E. coli, Listeria
Common causes of pneumonia in neonates (< 4wks)
Group B streptococci E. coli
Toxicity of macrolides (Erythromycin, azithromycin, clarithromycin)
GI discomfort (most common cause of noncompliance) Acute cholestatic hepatitis Eosinophilia Skin rashes Increases serum concentration of theophyllines, oral anticoagulants.
UTI bugs: Serratia maracescens Features?
Some strains produce a red pigment; often nosocomial and drug-resistant.
Eggs are visible in feces; intestinal infxn. Tx: Mebendazole/pyrantel pamoate.
Ascaris lumbricoides (giant round worm)
Babesia: How is it diagnosed?
Blood smear, no RBC pigment, apears as "maltese cross"
Intracellular Bugs: Name the 2 obligate intracellular organisms
Rickettsia, Chlamydia - "They stay inside (cells) when it's Really Cold"
Cholera and Pertussi toxins: How does Pertussis toxin work?
Permanently disables Gi, causing whooping cough, also promotes lymphocytosis by inhibiting chemokine receptors
Sexually transmitted diseases: What are the three clinical stages of syphilis
1st degree, 2nd degree, and thrid degree
Most likely pathogen in HIV+ adult: non-Hodgkin lymphoma, large-cell type, esp in lymphoid tissue around oropharynx
EBV- happens b/c cytotoxic lymphocytes are so important in controlling EBV-induced proliferation
G(-) Rods | Lactose fermenters | ?
Fast fermenters: Klebsiella E. coli Enterobacter Slow fermenters : Citrobacter Serratia (others)
UTI Bugs: Two UTI bugs that are nosocomial and drug resistant
Pseudomonas aeruginosa and Serratia marcescens
Osteomyelitis in most ppl is due to...? Who gets most osteomyelitis?
Staph aureus in most ppl. Most osteomyelitis occurs in children.
Name the causes of meningitis in the following age groups:: Newborn (0-6 months)
Group B strep, E. coli, Listeria
Gram (+) | Cocci | Catalase (-), in chains (Streptococcus) | partial hemolysis (green - alpha hemolysis) | ?
(+) Quellung (has capsule), Optochin sensitive, Bile soluble: Streptococcus pneumoniae (-) Quellung (no capsule), Optochin resistant, not bile soluble: Streptococcus viridans
Staph aureus: What is the function of protein A?
Virulence factor - binds to Fc-IgG and inhibits complement fixation and phagocytosis
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