Block 9 Enviroment Path And Antibiotic MCQ's
- 1.
A 65 year old retiree is admitted in respiratory failure. His past medical history is significant for rheumatoid arthritis. He dies and an autopsy reveals distinctive pulmonary lesions with central necrosis, surrounded by palisading fibroblasts, plasma cells, and macrophages containing anthraocotic pigment. What was this patient's most likely occupation?
- A.
Coal miner
- B.
Construction worker
- C.
Quarry miner
- D.
Nuclear plant worker
- E.
Ceramic artist
Correct Answer
A. Coal minerExplanation
Coal workers' pneumoconiosis, severe state, develops after the initial, milder form of the disease known as ANTHRACOSIS (anthrac — coal, carbon). This is often asymptomatic and is found to at least some extent in all urban dwellers due to air pollution. Prolonged exposure to large amounts of coal dust can result in more serious forms of the disease, simple coal workers' pneumoconiosis and complicated coal workers' pneumoconiosis (or Progressive massive fibrosis, or PMF). More commonly, workers exposed to coal dust develop industrial bronchitis, clinically defined as chronic bronchitis (i.e. productive cough for 3 months per year for at least 2 years) associated with workplace dust exposure. The incidence of industrial bronchitis varies with age, job, exposure, and smoking. In nonsmokers (who are less prone to develop bronchitis than smokers), studies of coal miners have shown a 16% to 17% incidence of industrial bronchitis.Rate this question:
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- 2.
A 16 year old girl commits suicide. A toxicology screen shows the presences of alcohol, cocaine, heroin, and some over the counter pain relievers. A section of her liver reveals massive centrilobular necrosis. Which of the following is most likely the cause of her death?
- A.
Tylenol overdose
- B.
Alcohol overdose
- C.
Cocaine overdose
- D.
Heroin overdose
Correct Answer
A. Tylenol overdoseExplanation
centrilobular necrosis means necrosis around the central vein (called zone 3)and has more Cyt-P450 so is more likely to be injured by drugs also alcohol(there is also alcohol dehydrogenase and SER) area around the portal vein is called zone 1 and has a lot of GLUTATHIONE in fulminant hepatitis and halothane type 2 toxicity, and tylenol, alcohol tox.
remember cetrilobular=zone3=central vein=least oxygen, most p450.Rate this question:
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- 3.
You are asked to implement a cancer screening program for workers at increased risk for developing cancer. Which of the following workers would NOT benefit the most from this information?
- A.
Anthracite coal workers
- B.
Quarry miners
- C.
Asbestos workers
- D.
Nuclear plant workers
- E.
Aerospace plant workers
Correct Answer
A. Anthracite coal workersExplanation
Anthracite coal workers would NOT benefit the most from the cancer screening program because although they are exposed to coal dust, which can be a potential carcinogen, the other workers listed are exposed to more well-known and established carcinogens such as asbestos, radiation, and chemicals used in aerospace plants. Therefore, the other workers have a higher risk of developing cancer and would benefit more from the screening program.Rate this question:
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- 4.
You are asked to give an educational seminar at an alcoholic's anonymous meeting. You begin by saying that chronic alcoholism may affect all organs and tissues. A participant asks you what organs are affected the most. You should respond by saying:
- A.
Brain & bone marrow
- B.
Pancreas & GI tract
- C.
Brain & liver
- D.
Heart & liver
- E.
Liver- & stomach
Correct Answer
E. Liver- & stomachExplanation
Chronic alcoholism primarily affects the liver and stomach. The liver is responsible for metabolizing alcohol, and long-term alcohol abuse can lead to liver damage such as fatty liver, alcoholic hepatitis, and cirrhosis. The stomach can also be affected as alcohol irritates the lining, leading to inflammation, ulcers, and an increased risk of gastrointestinal bleeding. While other organs may be impacted to some extent, the liver and stomach are the most commonly affected organs in chronic alcoholism.Rate this question:
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- 5.
A 12 year-old boy stated to develop episodes of upper respiratory discomfort characterized by nasal stuffiness accompanied by watery nasal and eye discharges. He lives in a small apartment but the "extended" family includes 3 cats and two dogs. He does not have these attacks at school which is several miles from home. Which of the following is germane to his condition?
- A.
He should be isolated from other family members
- B.
A skin test would probably show a" wheal and flare" reaction
- C.
Psychological counseling might help alleviate the situation
- D.
Sjogren's syndrome is a real possibility
- E.
If this persists he is at risk of nasopharyngeal carcinoma
Correct Answer
B. A skin test would probably show a" wheal and flare" reactionExplanation
The correct answer suggests that the boy is most likely experiencing allergies, specifically allergic rhinitis. The presence of pets in the small apartment indicates a potential trigger for his symptoms. A skin test showing a "wheal and flare" reaction is commonly used to diagnose allergies. This type of reaction occurs when the skin becomes raised and red, indicating an allergic response. Therefore, the answer suggests that the boy should undergo a skin test to confirm if his symptoms are indeed caused by allergies.Rate this question:
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- 6.
A major independent risk factor for myocardial infarction, and acts synergistically with other risk factors, such as high blood pressure and elevated blood cholesterol levels is:
- A.
Repeated viral infections
- B.
Alcohol consumption
- C.
High carbohydrate intake
- D.
Cigarette smoking
- E.
Environmental CO pollution
Correct Answer
D. Cigarette smokingExplanation
Cigarette smoking is a major independent risk factor for myocardial infarction. It not only increases the risk of heart attack on its own but also acts synergistically with other risk factors such as high blood pressure and elevated blood cholesterol levels. Smoking damages the blood vessels, increases blood clotting, reduces oxygen supply to the heart, and promotes the development of atherosclerosis, all of which contribute to the increased risk of myocardial infarction.Rate this question:
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- 7.
Regarding electrical injury, among the following statements choose the best answer:
- A.
Damage is produced only through an electrical dysfunction of cardiovascular conduction system.
- B.
The amount of current necessary to produce a disruption depends on its pathway through the brain
- C.
Electrical burns of the skin do not reflect the voltage, the area of electrical conductance, and the duration of current flow.
- D.
Because electrical energy has the potential to disrupt the electrical system within the heart, it frequently causes death through ventricular fibrillation
- E.
Damage is caused through the conversion of electrical energy to electromagnetic energy when the current encounters the resistance of the tissues
Correct Answer
D. Because electrical energy has the potential to disrupt the electrical system within the heart, it frequently causes death through ventricular fibrillationExplanation
The given answer explains that electrical energy has the potential to disrupt the electrical system within the heart, leading to ventricular fibrillation, which is a life-threatening condition. This is a well-known fact in the field of electrical injury. Ventricular fibrillation is a chaotic, irregular heartbeat that can result in cardiac arrest and death if not treated immediately. Therefore, this statement provides a clear and accurate explanation of the relationship between electrical energy and its potential consequences on the heart.Rate this question:
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- 8.
Which of the following beta-lactam antibiotics has only single ring in its structure?
- A.
Penicillin G
- B.
Cefotetan
- C.
Aztreonam
- D.
Ampicillin
- E.
Imipenem
Correct Answer
C. AztreonamExplanation
Aztreonam is the correct answer because it is the only beta-lactam antibiotic listed that has only a single ring in its structure. Penicillin G, Cefotetan, Ampicillin, and Imipenem all have multiple rings in their structures.Rate this question:
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- 9.
Which of the following molecular actions is catalyzed by the penicillin binding proteins in cell wall synthesis?
- A.
The transport of penicillins through the poring channels
- B.
The transpeptidation reaction
- C.
The breakdown of the beta-lactarn ring
- D.
The binding of penicillins to peptidoglycan layer
Correct Answer
B. The transpeptidation reactionExplanation
Penicillin binding proteins (PBPs) are enzymes that catalyze the transpeptidation reaction in cell wall synthesis. This reaction involves the cross-linking of peptidoglycan chains, which strengthens the cell wall structure of bacteria. PBPs bind to penicillins, which are antibiotics that inhibit their activity, leading to cell wall damage and bacterial death. Therefore, the transpeptidation reaction is the molecular action catalyzed by PBPs in cell wall synthesis.Rate this question:
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- 10.
Which of the following is a mechanism of resistance to beta-lactam antibiotics?
- A.
Increased affinity of penicillin binding protein to the drug
- B.
Inhibition of drug binding to 50S subunit
- C.
Hydrolysis of beta-lactams by bacterial beta-lactamases
- D.
Inhibition of the efflux pump of bacteria membrane
- E.
Increased production of autolytic enzymes
Correct Answer
C. Hydrolysis of beta-lactams by bacterial beta-lactamasesExplanation
Bacterial beta-lactamases are enzymes that can hydrolyze beta-lactam antibiotics, rendering them ineffective. This mechanism of resistance allows the bacteria to break down the beta-lactam ring in the antibiotic structure, preventing it from inhibiting cell wall synthesis. This is a common mechanism of resistance seen in many bacteria, and it can be overcome by using beta-lactamase inhibitors in combination with beta-lactam antibiotics.Rate this question:
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- 11.
A 5-year-old boy presented with fever and sharp pain at his left ear. On physical examination the left tympanic membrane was red, opaque and bulging. Amoxicillin was prescribed but three days later the symptoms were not reduced. The pediatrician decided to modify the therapy and prescribed amoxicillin/potassium clavulanate. Which of the following statement best explains the advantage to add potassium clavulanate to amoxicillin?
- A.
The drug inhibits the bacterial inactivation of amoxicillin
- B.
The drug is active against Pseudornonas and Serratia species
- C.
The drug inhibits the renal secretion of arnoxicillin
- D.
The drug increases amoxicillin penetration through bacterial membrane
- E.
The drug inhibits the synthesis of peptidoglycan
Correct Answer
A. The drug inhibits the bacterial inactivation of amoxicillinExplanation
Adding potassium clavulanate to amoxicillin helps to inhibit the bacterial inactivation of amoxicillin. This is important because some bacteria produce enzymes called beta-lactamases, which can break down and inactivate amoxicillin. Potassium clavulanate is a beta-lactamase inhibitor, meaning it prevents these enzymes from inactivating amoxicillin. By inhibiting the bacterial inactivation of amoxicillin, the combination of amoxicillin and potassium clavulanate can effectively treat the infection.Rate this question:
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- 12.
Which of the following statements best explains why broad-spectrum penicillins can cause superinfections?
- A.
They lower the immunological defense of the host
- B.
They select viral mutants resistant to most antimicrobial drugs
- C.
They mask the symptoms of the disease which can progress undetected
- D.
They alter the normal microflora of the host
- E.
They block the activity of mediators of the normal inflammatory reaction
Correct Answer
D. They alter the normal microflora of the hostExplanation
Broad-spectrum penicillins can cause superinfections because they alter the normal microflora of the host. These antibiotics not only target the pathogenic bacteria causing the infection but also disrupt the balance of beneficial bacteria in the body. This disruption can lead to the overgrowth of opportunistic pathogens, causing secondary infections that may be resistant to the penicillin or other antimicrobial drugs.Rate this question:
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- 13.
Which of the following statements regarding fluoroquinolones are correct?
- A.
They prevent the relaxation of supercoiled DNA
- B.
Their ultimate effect is mainly bacteriostatic
- C.
Resistance is completely crossed between quinolones and sulfonamides
- D.
They are primarily effective against gram positive bacteria
- E.
They are much safer than penicillins during pregnancy
Correct Answer
A. They prevent the relaxation of supercoiled DNAExplanation
Fluoroquinolones prevent the relaxation of supercoiled DNA by inhibiting the action of DNA gyrase, an enzyme responsible for unwinding DNA during replication and transcription. This prevents the bacteria from replicating and ultimately leads to their death. The statement is correct as it accurately describes one of the mechanisms of action of fluoroquinolones.Rate this question:
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- 14.
A 22-year-old man was admitted to the hospital because of an erythematous, macular eruption on the extremities, followed by the appearance of vesicles and bullae on the lips, oral mucosa, anogenital region and conjunctiva, Few days ago he started a treatment with trimethopr}m-sulfamethoxazole for an acute pharyngitis. Vital signs on admission were: temperature 103 F, pulse 120 bpm, blood pressure 120178 mm Hg, respirations 30/min. Which of the following best explains the syndrome of this patient?
- A.
Lupoid syndrome
- B.
Stevens-Johnson syndrome
- C.
Disulfiram reaction
- D.
Dermatophytosis
- E.
Bilirubin encephalopathy
Correct Answer
B. Stevens-Johnson syndromeExplanation
The patient in this scenario is presenting with an erythematous, macular eruption followed by vesicles and bullae on various parts of the body, including the lips, oral mucosa, anogenital region, and conjunctiva. This is consistent with the clinical presentation of Stevens-Johnson syndrome (SJS). SJS is a severe and potentially life-threatening skin reaction that is often triggered by medications, such as trimethoprim-sulfamethoxazole. The patient's vital signs, including a high temperature, elevated heart rate, and increased respiratory rate, are also indicative of the systemic inflammatory response seen in SJS.Rate this question:
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- 15.
Which of the following statement correctly pairs the binding site of gentamicn with the action that follows that binding?
- A.
30S ribosomal subunit - misreading of mRNA template
- B.
50S ribosomal subunit- blockade of transpeptidase enzymes
- C.
30S ribosomal subunit- blocks the entry of aminoacyl tRNA
- D.
50S ribosomal subunit - blockade of translocation of peptidyl-tRNA
- E.
Cell wall - blockade of elongation of peptidoglycan chain
Correct Answer
A. 30S ribosomal subunit - misreading of mRNA templateExplanation
The correct answer is 30S ribosomal subunit - misreading of mRNA template. This is because gentamicin is an antibiotic that binds to the 30S ribosomal subunit in bacteria, which is responsible for reading the mRNA template during protein synthesis. When gentamicin binds to this site, it causes the ribosome to misread the mRNA template, leading to the incorporation of incorrect amino acids into the growing protein chain. This ultimately results in the production of nonfunctional or faulty proteins, leading to the inhibition of bacterial growth and reproduction.Rate this question:
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- 16.
A 67-year-old man has been receiving an antibiotic for three weeks to treat a urinary tract infection apparently due to Pseudomonas aeroginosa. Now the patient complains of headache, nausea and vomiting, vertigo, tinnitus, and a decreasing nearing capacity, The drug used was most likely a member of which of the following antibiotic classes?
- A.
Penicillins
- B.
Fluoroquinolones
- C.
Cephalosporins
- D.
Sulfonamides
- E.
Aminoglycosides
Correct Answer
E. AminoglycosidesExplanation
Based on the symptoms described, the patient is experiencing ototoxicity, which is a known side effect of aminoglycosides. Ototoxicity can cause symptoms such as headache, nausea and vomiting, vertigo, tinnitus, and a decreasing hearing capacity. Therefore, the drug most likely used to treat the urinary tract infection was a member of the aminoglycosides antibiotic class.Rate this question:
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- 17.
A 25-year-old woman, late in her third trimester of pregnancy, presented with low grade fever and burning upon urination. The history of the patient was significant for a recurrent urinary tract infection. An antibiotic was prescribed which resulted in arthropathy in the new born. The prescribed antibiotic most likely acts by:
- A.
Inhibition of DNA gyrase
- B.
Inhibition of protein synthesis by binding to 30S subunit of ribosome
- C.
Binding to D-Ala-D-Ala terminus of peptidoglycan
- D.
Inhibition of Folic acid synthesis
Correct Answer
A. Inhibition of DNA gyraseExplanation
Quinolones should not be used in the pregnant female.Rate this question:
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- 18.
A 6-year-old boy presented with low grade fever, sore throat, nonproductive cough and headache. Physical examination revealed a maculopapular rash over the trunk and chest x- ray showed extensive nodular infiltrates in the left lower lobe. The presumptive diagnosis of mycoplasmal pneumonia was confirmed later by the complement fixation test. Which of the following drugs would be appropriate for this boy?
- A.
Tetracycline
- B.
Erythromycin
- C.
Ampicillin
- D.
Ceftazidime
- E.
Streptomycin
- F.
Metronidazole
Correct Answer
B. ErythromycinExplanation
The correct answer is Erythromycin because it is the drug of choice for treating mycoplasmal pneumonia in children. Mycoplasma pneumoniae is a common cause of respiratory tract infections in children, and erythromycin is effective against this bacteria. Tetracycline is contraindicated in children due to its potential for causing tooth discoloration. Ampicillin and ceftazidime are not effective against mycoplasma. Streptomycin is not commonly used for treating mycoplasmal pneumonia, and metronidazole is not effective against bacteria.Rate this question:
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