Were do we find Muscarinic and Nicotinic receptors?
Muscarinic -> cell membranes of visceral organs & glands
Nicotinic -> cell m. of skeletal muscles & nerve ganglia
What best illustrates the difference in interpersonal sensitivity to increasing doses of a drug?
Quantal dose-response curve
What can be derived from a drug concentration-response curve and used to compare the potency of drugs that produce the same response?
EC50 (effective comcentration 50)
What is β-lactamases & function?
β-lactamases are enzymes produced by bacteria that provide multi-resistance to beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, monobactams and carbapenems (ertapenem)
Which antibacterial drug can be administered orally to a patient before colorectal surgery to reduce the number of intestinal bacteria & why?
Aminoglycoside
(poorly absorbed in GI tract -> sterilizes bowel)
What has been developed as a new class of ergosterol biosynthesis inhibitor for the treatment of Tinea pedis & how administered?
Terbinafine (orally & topically)
What diagnostic parameters are used to obtain post test probability of a test?
Prevalance/Pretest Probability
LR+
LR-
What is a ROC curve & function?
ROC -> Receiver Operating Characteristics
The area under the ROC curve of a test can be used as a criterion to measure the test's discriminative ability, i.e. how good is the test in a given clinical situation.
How do yu calculate sensitivity, specifity, positive and negative predictive value?
sensitivity a/a+c
specifity d/b+d
positive predictive value a/a+b
negative predictive value d/c+d
What is an ecological study?
analyze routine based data -> provide quick and cheap data on a possible hypothesis since
The relationship between exposure and dependent variable is examined using scatter plot graphs.
They are useful to develop hypothesis but the conclusions may be flawed due to ecological fallacy
What are examples of carrier state microorganisms?
Staphylococcus aureus in anterior nares
Neisseria meningitidis in nasopharynx
Streotococcus ğneumoniae in nasooharynx
What are Lactobacillus spp & where?
Lactobacillus spp -> smbiotic members in the vagina of a women in childbearing age
What causes most of the urinary catheter or ventilator related infections & why?
Pseudomonas spp & Acinetobacter spp
(survive in water)
What is used to monitor the effectiveness of killing with autoclave sterilization (moist heat)
Geobacillus Steatothermophilus spores
What is the smalleat bacteria infecting humans + characteristics?
Mycoplasmas
-> Cytoplasmic membrane contain sterols
-> Lack cell wall
How do bacterial capsules inhibit phagocytosis?
Capsules inhibit phagocytosis by depositing factor H which in turn degrades C3b
How can we serotype Streptococcus pneumoniae?
Streptococcus pneumoniae can be serotyped by using quellung reaction based on capsule swelling in the presence of homolog antiserum.
What is the antigen of Pneumococcus vaccine and Haemophilus influenzae type b vaccine
capsular polysaccharides as antigens
What do beta-lactam antibiotics target?
transpeptidation reactions catalyzed by penicillin-binding proteins
What happens to bacteria due to stressors
may lose their cell walls -> become cell wall-deficient bacteria (L-forms)
Where do we find Lysosyme & function?
Lysosyme in human secretions attack the glycosidic bond between NAG and NAM residues.
How do Helicobacter pylori, Vibrio cholera or Streptococcus pyogenes gain access to deeper tissues?
Helicobacter pylori & Vibrio cholera -> disruption of intracellular junctions
Streptococcus pyogenes -> tissue-degrading enymes
What is the toxic part in Endotoxins?
Lipid A
What is used for the classification of fungi?
Sexual spores
Which spores help fungi to survive inappropriate environmental conditions?
Chlamydospore
Which virulence factors are important in the pathogenesis of Aspergillus infections?
Phospholipase secretion
Cell wall pigments
Gliotoxin
Overexpression of efflux pumps cause resistance to which antifungal drugs?
Terbinafine
Fluconazole
Amorolfine
Which fungal infection can be diagnosed by examining KOH preparations revealing short unbranched hyphae and budding yeast cells (meat ball & pasta appearance)?
Tinea versicolor
A 50 year old gardener presented a subcutaneous lesion on his hand. It has started a few days after a wound while digging the soil in the garden. The lesion did not heal despite use of an antibiotic cream. The lesion got ulcerated and spread to his arm.
The histopathological examination of the biopsy specimen revealed asteroid bodies.
Diagnose
Sporotrichosis
Sporothrix schenkii is an environmental fungi and can cause subcutaneous infections when bypasses the skin barrier.
When do we see Id reactions
ld reactions are seen with dermatophyr infections (superficial fungal infections).
How are systemic mycoses transmitted?
İnhalation of conidia
What fungi cause thrush in newborn babies?
Candida albicans
A rhinocerebral infection has been suspected in a patient with diabetic ketoacidosis.
Gram stain of the sinus aspirate showed broad, nonseptate hypha branching at right angles. The culture of the specimen revealed a mold.
What is the diagnosis for this patient?
Mucormycosis
What attacks the peptidoglycan layer on bacteria?
Lysozyme
Describe the correct chronological order of the T cell status, from the entrance to the Thymus until it becomes a functional effector cell after its interaction with an Antigen.
Immature T cell, Naive T cell, Activated T cell
Name PAMPs
Flagrllin
LPS
Mannose
Double strand RNA
What are the genes in the MHC class I & II loci?
MHC I -> HLA A, B, C
MHC II -> HLA DP, DQ, DR
What are MHC I molecules assoc. with?
beta 2 Microglobulin
What does TCR bind?
MHC bound antigens
Why does the immune response differ among individuals?
Polymorphism of cytokine and chemokine genes
Individual polymorphisms of MHC genes that control peptide binding
Variations in immune regulation through the number or function of Treg cells
Non-MHC genes that regulate the activity of Antigen Presenting Cells such as macrophages
What is essential for Treg, what fct & what if deficient?
FoxP3 gene essential
Treg supress Th1 & Th2 responses
deficiency -> IPEX (İmmune dysregulation polyendocrinopathy enteropathy x-linked)
Which immunoglobulin class is the most efficient to produce a Precipitation reaction, such as in an Ouchterlony immunoprecipitation test?
IgG
bc high affinity, bivalent binding to induce immune complex lattice formation leading to precipitation
E.coli
What is more resistant to bacterial beta lactamase enzyme penicillin or cephalosporins?
The cephalosporins are usually more resistant than the penicillins to the bacterial beta-lactamase enzymes
Trichophyton spp
What does a Nitrite positivity in the urine dipstick test indicate?
Nitrite positivity in the urine dipstick test indicates a Gram negative enteric bacteria in the urine sample
What is used to treat Urinary tract infections?
Nitrofurantoin
southeastern U.S.
sputum smear revealing thick-walled, refractile, doublecontoured yeast cells
What described & common site of dissemination?
Blastomyces dermatitidis
most common site of dissemination skin
What attacks the lipid bilayer in bacteria?
Defensins
What is the function of echinocandins?
echinocandins, inhibit glucan synthesis
What is a potent inhibitor of RNA and DNA synthesis?
5 Flucytosine
How does azole work?
inhibit enzyme responsible for conversion of lanosterol to ergosterol (major component of the fungal cell membrane)
What do allylamines do?
inhibition of an enzyme in the early stages of ergosterol synthesis.
How does fungi reproduce and what are the forms called?
reproduce asexual or sexual
sexual form -> teleomorph
asexual form -> anamorph (repr. element conidia)
What is more sensitive than conventional acid-fast staining to detect acid-fast bacteria?
Fluorescent stains like auramine-rhodamine
What are common features of Neisseria meningitidis, Streptococcus pneumoniae and Haemophilus influenzae & difference?
Common
IgA1 protease
Polysaccharide capsule
Nasopharynx colonization
Cause meningitis
Vaccines available
Difference
Neisseria meningitidis -> Gram neg. diplococci
Streptococcus pneumoniae -> Gram pos. diplococci
Haemophilus influenzae -> Gram neg. coccobacilli
What is the causative agent and is it Catalase, Coagulasepositive or negative & novobiocin sensitive or resistant?
S.saprophyticus
catalase positive
coagulase negative
novobiocin resistant
What does sensitivity, specifity, positive & negative predictive value mean?
Sensitivity is “proportion of people who have a positive test result among people with the disease
Specifity is “proportion of people who have a negative test result among people WITHOUT the disease ”.
Positive predictive value is “proportion of people who have disease among positive test results”.
Negative predictive value is “proportion of people who do not have disease among negative test results”.
Which immunoglobulin isotype crosses the gut epithelium of infants?
IgA (in breastmilk)
What is Cefoxitin disk & function
Cefoxitin disk, is a known inducer of mecA gene in S aureus so it is necessary to apply during antimicrobial susceptibility testing
What bacteria can survive and grow in phagocytes by inhibiting the phagosome-lysosome fusion and/or by inhibiting the acidification process
Mycobacterium tuberculosis
Legionella pneumophilia
What is used for serological diagnosis of Aspergillus
Galactomannan
How are molds most often identified?
by the morphology of their conidia and conidiophores
A 40-y.o. woman recently diagnosed with a urinary tract infection receives a trimethoprim−sulfamethoxazole combination. Although, both antibiotics are bacteriostatic when given alone, a bactericidal effect is obtained when the two given in combination. How do you best define this drug interaction?
Synergism -> response elicited by combined drugs is greater than the combined responses of the individual drugs
(bactericidal effect is greater than a bacteriostatic)
Infective organism was resistant to piperacillin. What drug group & mechanism of bacterial resistance to this antibiotic?
piperacillin -> β-lactam antibiotic
Production of β-lactamase enzymes
Development of penicillin-binding proteins that have decreased affnity for the antibiotic
Decreased permeability of the cell membrane to the drug
Development of an active efflux pump
What is the primary advantage of liposomal preparations over the regular colloidal suspension of amphotericin B?
Reduced nephrotoxicity
Which of the following may have caused red urine in a 50-y.o. Chinese man with atrial fibrillation taking standard doses of warfarin, an anticoagulant drug metabolized by the CYP2C9 isozyme?
caused by excessive anticoagulation due to decreased metabolism of warfarin via the CYP2C9 enzyme
How do you visualize spirochetes of syphilis?
Dark-field microscopy
A 76–year–old woman with a prosthetic (artificial) hip comes to you complaining of fever and pain in
that joint. You are concerned about an infection by Staphylococcus epidermidis. Using your
knowledge of normal flora, what is the most likely source of this organism?
Skin
Vascular catheter-related bloodstream infections are mostly due to what bacteria?
Gram positive cocci, especially Staphylococcus aureus & Staphylococcus epidermidis
The colon is the site of the largest number of normal flora bacteria most of which are anaerobic. Which one of the following bacteria is found in the greatest number in the colon?
Bacteroides fragilis
A 45-year-old woman has an inflamed ulcer on her right hand and several tender nodules on the inner aspect of her right arm. She is a gardener and especially likes pruning her roses. Biopsy of the lesion reveals budding yeasts. Which of the following is the most likely cause?
Sporothrix schenckii
A 45-year-old woman having chemotherapy via a subclavian catheter for acute leukemia has developed fever of 39°C. Her total white blood cell (WBC) count is 12.90*103/µL. Blood cultures grew budding yeasts that formed germ tubes. What is the most likey cause?
A farmer from South America presents to an urgent care facility with acneiform eruptions on his trunk and extremities. He denies any recent illness or travel. Several months ago he was admitted with a dry cough but required no treatment. On physical examination, the papules and pustules with the absence of true comedones are present mainly over trunk and back. A biopsy of skin lesions was taken and sent for histopathology. The specimen tissue showed spherule (more substantial in diameter than an RBC) filled with endospores. Which of the following may be responsible for his clinical presentation?
C.immitis
An 10-year-old boy has a pruritic rash on his chest. Lesions are round or oval with an inflamed border and central clearing. Fungal culture of the skin scrapings from the lesion revealed only macroconidia on lactophenol cotton staining. What is the most likely cause?
E.floccosum
What are the most important receptors for fungi?
a lectin-like structure on phagocytes (dectin-1) that binds glucan, and Toll-like receptors (TLR2, TLR4)
What is the newly formed daughter cell of yeasts often called?
blastoconidium
What does Caspofungin have a good function against?
Candida and Aspergillus
What term is associated with the antigen presentation for the intracellular organisms?
Proteasome
What attacks the chemical bonds between N-acetylglucosamine and N-acetylmuramic acid to destroy
the Peptidoglycan layer in gram-positive bacteria?
Name Pattern Recognition Receptors
RIG-like receptors
C-type Lectin receptors (MBL)
Toll Like receptors (TLR)
NOD-like receptors
Which immunoglobulin isotype crosses the placenta?
What is the function of Fc receptors on immune cells?
bind the heavy chain of IgG (Fc) to promote opsonization and phagocytosis
Assume you are working in a clinic with a high prevalence of a disease. Which diagnostic tests should you prefer to rule in that disease?
The test with a high LR+ & high specificity
What approach is used to obtain the cutoff value of a biochemical laboratory test?
ROC curve
A 95% confidence interval estimate for the difference between two population means, is determined to be (62.75, 68.52.) Assume you increased the number of people in each sample and calculate 95% confidence interval of the difference again. Which of the following is correct for the width of the confidence interval?
becomes narrower
The grades on the exam for biostatistics are normally distributed with a mean of 75.0 and a standard deviation of 5.0. A student scored 85.0 on the exam. Approximately what % of the class scored higher than that student?
2.5%
bc ~95% in area of standard deviation rest below & above
What criteria can be used to define a new disease?
Common symptoms occurring more often in patients than others of similar age, gender, social class etc.
Similar epidemiological patterns seen in different geographical regions.
Clustering of common symptoms more frequently in patients.
How do those bacteria survive phagocytosis?
Streptococcus pyogenes
Helicobacter pylori
Vibrio cholera
Legionella pneumophilia -> inh. the phagosome-lysosome fusion and/or acidification
Streptococcus pyogenes -> disrupt extracellular matrix by enzymes like collagenase and hyaluronidase
Mycobacterium tuberculosis -> inh. the phagosome-lysosome fusion and/or acidification
Helicobacter pylori -> disrupt intercellular junctions
Vibrio cholera -> disrupt intercellular junctions
What class of antibiotics could be combined w ith aminoglycosides to produce a synergistic bactericidal action?
cephalosporins
What effect does atropine have on drug absorption & why?
Delays drug absorption bc gatric emptying delayed
What Gram positive cocci resistant to novobiocin & other tests & what disease?
Staphylococcus saprophyticus
Catalase positive & Coagulase negative
UTI
What is often causing neonatal sepsis
Streptococcus agalactiae
An 84-year-old man presents with 4 days of headache and fever. A lumbar puncture is performed, and cerebral spinal fluid cultures are obtained. Bacterial meningitis is confirmed. The bacterium responsible can translocate from cell to cell via actin polymerization. What is the bacteria, how did he get it and what is most likely seen on Gram stain?
Listeria monocytogenes
Gram positive rod
a foodborne illness, can causr meningitis
Actin polymerization allows the bacteria to move quickly from cell to cell
Which immunoglobulin class is the most efficient to produce an Complement activation?
IgM
What is common & different between S. epidermidis and S. saprophyticus?
both Catalase pos & Coagulasr neg
S. epidermidis novobiocin sensitive, S. saprophyticus resistant
Which of the following Candida species produces chlamydospores?
What is a sexual spore of fungi?
Basidiospore
What is an asexual fungal spore
Blastospore (of yeast)
Chlamidospore (of candida)
Sporangiospore (Mucor mycetes)
Arthrospore (by fragmentation of hyphal segments)
Which reproduces only as a yeast colony?
Cryptococcus neoformans
What fungi enters the tissue as a result of trauma and causes infection?
Sporothrix schenkii
Which of the following is one of the primary pathogenic fungi?
Coccidioides immitis
Which dermatophyte form microconidia?
Trichophyton rubrum
Microsporum canis
Trichophyton violaceum
Trichophyton mentagrophytes
What is the most common clinical form of mucormycosis?
Rhinoorbitocerebral mucormycosis
A 16-year-old boy presents to the emergency department with headaches and
vomiting. He was discharged four days ago after sustaining a basilar skull fracture
while playing hockey. Vital signs are temperature 38.6º C heart rate 112 bpm, and
blood pressure 129/78 mmHg. He is pale and covering his eyes. The CSF culture
revealed Gram positive alpha hemolytic colonies on blood agar. The colonies were
optochin sensitive and bile soluble. What is the most likely organism causing his
illness?
Streptococcus pneumoniae
What cells presents antigens and activates naive T cell?
Dendritic cells
What function do Th1 & 2 have?
Th1: induce mactophage activation
Th2: induce IgE productşon, act against helminthic parasites, signature cytokinr Il4
What is the function of M cells?
take up a variety of antigens from the gastrointestinal lumen, transport them by transcytosis across the cell and deliver them to immune cells
What provides immunity faster vaccine or immunoglobulin serum?
Immunoglobulin preparation
Which agents reported and examined by a sample of health institutions according to the sentinel surveillance system in Türkiye?
Severe acute respiratory Illness (SARI)
Influenza-like illness (ILI)
Which vaccines should be added to the vaccination schedule according to the vaccine advisory committee recommendations?
Human papilloma virus
meningococcal vaccination
Influenza
What binds longer peptides MHC I or II?
MHC II
Whatis the result of E.coliin those tests
Indole
methyl red
Voges proskaeur
citrate
E.coli. Indole (+), methyl red (+), Voges proskaeur (-), citrate (-)
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