The primary mechanism underlying the resistance of gram-positive organisms to macrolide antibiotics is (a) Methylation of binding sites on the 50S ribosomal subunit (b) Formation of esterases that hydrolyze the lactone ring (c) Increased activity of efflux mechanisms (d) Formation of drug-inactivating acetyltranferases (e) Decreased drug permeability of the cytoplasmic membrane

1 Answer

Answer :

Ans: A

Related questions

Description : The mechanism of antibacterial action of tetracycline involves (a) Binding to a component of the 50S ribosomal subunit (b) Inhibition of translocase activity (c) Blockade of binding of ... (d) Selective inhibition of ribosomal peptidyl transferases (e) Inhibition of DNA-dependent RNA polymerase

Last Answer : Ans: C

Description : The most important mechanism by which gram negative bacilli acquire chloramphenicol resistance is (a) Decreased permeability into the bacterial cell (b) Acquisition of a plasmid encoded ... bacterial ribosome for chloramphenicol (d) Switching over from ribosomal to mitochondrial protein synthesis

Last Answer : Ans: B

Description : The most important mechanism by which tetracycline antibiotics exert antiimicrobial action is (a) They chelate Ca2+ ions and alter permeability of bacterial cell membrane (b) They bind to 30S ribosomes ... peptide chain in the bacteria (d) They interfere with DNA mediated RNA synthesis in bacteria

Last Answer : Ans: B

Description : The most important mechanism by which gram negative bacilli acquire chloramphenicol resistance is: A. Decreased permeability into the bacterial cell B. Acquisition of a plasmid encoded ... the bacterial ribosome for chloramphenicol D. Switching over from ribosomal to mitochondrial protein synthesi

Last Answer : B. Acquisition of a plasmid encoded for chloramphenicol acetyl transferas

Description : The most important mechanism of bacterial resistance to an aminoglycoside antibiotic is (a) Plasmid mediated acquisition of aminoglycoside conjugating enzyme (b) Mutational acquisition of aminoglycoside ... affinity of ribosomal protein for the antibiotic (d) Mutational loss of porin channels

Last Answer : Ans: A

Description : The most important mechanism by which tetracycline antibiotics exert antimicrobial action is: A. They chelate Ca2+ ions and alter permeability of bacterial cell membrane B. They bind to 30S ribosomes ... peptide chain in the bacteria D. They interfere with DNA mediated RNA synthesis in bacteria

Last Answer : B. They bind to 30S ribosomes and inhibit bacterial protein synthesis

Description : The aminoglycoside antibiotic which is distinguished by its resistance to bacterial aminoglycoside inactivating enzymes is (a) Kanamycin (b) Sisomicin (c) Amikacin (d) Tobramycin

Last Answer : Ans: C

Description : Superinfections are more common with (a) Use of narrow spectrum antibiotics (b) Short courses of antibiotics (c) Use of antibiotics that are completely absorbed from the small intestines (d) Use of antibiotic combinations covering both gram positive and gram negative bacteria

Last Answer : Ans: D

Description : Bacteria develop tetracycline resistance by the following mechanisms except: A. Losing tetracycline concentrating mechanisms B. Elaborating tetracycline inactivating enzyme C. Synthesizing a protection protein' ... the target site D. Actively pumping out tetracycline that has entered the cell

Last Answer : B. Elaborating tetracycline inactivating enzym

Description : Beta - lactamase production by strains of Haemophilus influenzae, Moraxella catarrhalis, and Neissera gonorrhoeae confers resistance against penicillin G.which one of the following antibiotics is most likely to be ... ? (a) Ampicillin (b) Ceftriaxone (c) Clindamycin (d) Gentamicin (e) Piperacillin

Last Answer : Ans: B

Description : During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.

Last Answer : (c) association of 30S mRNA with formyl-met- tRNA

Description : .During translation initiation in prokaryotes, a GTP molecule is needed in (a) formation of formyl-met-tRNA (b) binding of 30S subunit of ribosome with mRNA (c) association of 30S mRNA with formyl-met- tRNA (d) association of 50S subunit of ribosome with initiation complex.

Last Answer : (c) association of 30S mRNA with formyl-met- tRNA

Description : Which binding is inhibited by pactamycin? A- Aminoacyl-tRNA to the A-site of 30S subunit B- Initiator-tRNA to 30S/40S initiation complexes C- Peptidyl t-RNA to the 50S subunit D- Formation of peptide bond in P site

Last Answer : Initiator-tRNA to 30S/40S initiation complexes

Description : Which fluoroquinolone has markedly enhanced activity against gram positive bacteria and anaerobes ? (a) Pefloxacin (b) Ciprofloxacin (c) Sparfloxacin (d) Norfloxacin

Last Answer : Ans: C

Description : Methicillin resistant staphylococci do not respond to ß-lactam antibiotics because (a) They produce a ß-lactamase which destroys methicillin and related drugs (b) They elaborate an amidase which destroys ... low affinity for ß-lactam antibiotics (d) They are less permeable to ß-lactam antibiotics

Last Answer : Ans: C

Description : The plasma half life of pencillin-G is longer in the new born because their (a) Plasma protein level is low (b) Drug metabolizing enzymes are immature (c) Glomerular filtration rate is low (d) Tubular transport mechanisms are not well developed

Last Answer : Ans: D

Description : Binding of formylmehtionyl tRNA to 30 S ribosomal subunit of prokaryotes is inhibited by (A) Streptomycin (B) Chloramphenicol (C) Erythromycin (D) Mitomycin

Last Answer : Answer : A

Description : eIF-1A and eIF-3 are required (A) For binding of amino acyl tRNA to 40 S ribosomal subunit (B) For binding of mRNA to 40 S ribosomal subunit (C) For binding of 60 S subunit to 40 S subunit (D) To prevent binding of 60 S subunit to 40 S subunit

Last Answer : Answer : D

Description : This drug has activity against many strains of Pseudomomas aeruginosa. However, when it is used alone, resistance has emerged during the course of treatment. The drug should not be used in ... with tazobactam (a) Amoxicillin (b) Aztreonam (c) Imipenem (d) Piperacillin (e) Vancomycin

Last Answer : Ans: D

Description : Which one of the following antibiotics is a potent inducer of hepatic drug-metabolizing enzymes? (a) Ciprofloxacin (b) Cyclosporine (c) Erythromycin (d) Rifampin (e) Tetracycline

Last Answer : Ans: D

Description : Spectinomycin is an aminoglycoside-like antibiotic indicated for the treatment of (a) Gram-negative bacillary septicemia (b) Tuberculosis (c) Penicillin-resistant gonococcal infections (d) Syphilis (e) Gram-negative meningitis due to susceptible organisms

Last Answer : Ans: C

Description : A high school student presents with headache, fever, and cough of 2 day's duration. Sputum is scant and nonpurulent and a Gram stain reveals many white cells but no organisms. Since this ... initiate treatment with (a) Cefazolin (b) Clindamycin (c) Erythromycin (d) Gentamicin (e) Trovafloxacin

Last Answer : Ans: C

Description : Widespread and prolonged used of an antibiotic leads to emergence of drug resistant strains because antibiotics (a) Induce mutation in the bacteria (b) Promote conjugation among bacteria (c) Allow resistant strains to propagate preferentially (d) All of the above

Last Answer : Ans: C

Description : Gram negative organisms are largely insensitive to benzyl penicillin because (a) They produce large quantities of penicillinase (b) They do not utilize D-alanine whose incorporation in the cell wall is ... lipoprotein-peptidoglycan multiplayer cell wall of gram-negative bacteria (d) Both (a) and (b)

Last Answer : Ans: C

Description : Tetracylin prevents synthesis of polypeptide by (A) Blocking mRNA formation from DNA (B) Releasing peptides from mRNA-tRNA complex (C) Competing with mRNA for ribosomal binding sites (D) Preventing binding of aminoacyl tRNA

Last Answer : Answer : D

Description : Under certain circumstances, the gut may become a source of sepsis and serve as the motor of systemic inflammatory response syndrome. Microbial translocation is the process by which microorganisms ... intestinal mucosal permeability c. Decreased host defense mechanisms d. Lack of enteral feeding

Last Answer : Answer: a, b, c, d 99 Translocation is promoted in three general ways: 1) altered permeability of the intestinal mucosa as caused by shock, sepsis, distant injury, or cell toxins; 2) ... trauma patient d. Fifty percent of non-nitrogen caloric requirements should be provided in the form of fat

Description : Peptidyl transferase activity is present in (A) 40 S ribosomal subunit (B) 60 S ribosomal subunit (C) eEF-2 (D) Amino acyl tRNA

Last Answer : Answer : B

Description : Of the following which is the most important mechanism of concurrent acquisition of multidrug resistance among bacteria ? (a) Mutation (b) Conjugation (c) Transduction (d) Transformation

Last Answer : Ans: B

Description : Bacteria become erythromycin resistant by the following mechanisms except: A. Becoming less permeable to erythromycin B. Elaborating an erythromycin esterase enzyme C. Elaborating a protection ... the erythromycin binding site D. Altering the ribosomal binding site through a methylase enzyme

Last Answer : C. Elaborating a ‘protection protein’ which blocks the erythromycin binding site

Description : Antibacterial agents can be classified with regard to their structure, mechanism of action, and activity pattern against various types of bacterial pathogens. Which of the following ... are both bacteriostatic d. Sulfonamides and trimethoprim act synergistically to inhibit purine synthesis

Last Answer : Answer: a, b, d Penicillins, cephalosporins, and monobactams possess a b-lactam ring of some type and act to bind bacterial division plate proteins, thus inhibiting cell wall ... act in different mechanisms to inhibit protein synthesis, therefore two agents in combination act synergistically

Description : Porins are located in A- the outer membrane of gram-negative bacteria B- he peptidoglycan layer of gram-positive bacteria C- the cytoplasmic membrane of both gram-negative and gram-positive bacteria D- the periplasmic space of gram-negative bacteria

Last Answer : the outer membrane of gram-negative bacteria

Description : Clarithromycin and erythromycin have very similar spectrums of antimicrobial activity. The major advantage of clarithromytcin is that it (a) Eradicates mycoplasmal infections in a single dose (b ... not inhibit live drug-metabolizing enzymes (e) Acts on methicillin-resistant strains of staphylococci

Last Answer : Ans: C

Description : Which one of the following statements about ampicillin is false? (a) Its activity is enhanced by sulbactam (b) It causes maculopapular rashes (c) It is the drug of choice for Listeria monocytogenes infection (d) It eradicates most strains of MRSA (e) Pseudomembranous colitis may occur with its use

Last Answer : Ans: D

Description : If therapy with multiple drugs causes induction of drug metabolism in your asthma patient, it will (a) Result in increased smooth endoplasmic reticulum (b) Result in increased rough endoplasmic reticulum ... soluble cytoplasmic fraction (d) Require 3-4 months to reach completion (e) Be irreversible

Last Answer : Ans: A

Description : Isoniazid is a primary antitubercular agent that (a) Requires pyridoxine supplementation (b) May discolor the tears, saliva, urine or feces orange-red (c) Causes ocular complications that are reversible if ... (d) May be ototoxic and nephrotoxic (e) Should never be used due to hepatotoxic potential

Last Answer : Ans: A

Description : Which of the following organisms is notorious for developing antimicrobial resistance rapidly ? (a) Streptococcus pyogenes (b) Meningococcus (c) Treponema pallidum (d) Escherichia coli

Last Answer : Ans: D

Description : In a patient with culture-positive enterococcal endocarditis who has failed to respond to vancomycin because of resistance, the treatment most likely to be effective is (a) Clarithromycin (b) Erythromycin (c) Linezolid (d) Minocycline (e) Ticarcillin

Last Answer : Ans: D

Description : Which one of the following antibiotics is likely to be most effective agent in the treatment of an infection due to enterococci if used in conjuction with penicillin G? (a) Amikacin (b) Gentamicin (c) Netilmicin (d) Streptomycin (e) Tobramycin

Last Answer : Ans: D

Description : What is the most important reason for restricted clinical use of chloramphenicol ? (a) Its narrow spectrum of activity (b) Emergence of chloramphenicol resistance (c) Its potential to cause bone marrow depression (d) Its potential to cause superinfections

Last Answer : Ans: C

Description : The mechanism of action of cyclosporine involves (a) Activation of calcineurin (b) Binding to cyclophilin to cause inhibition of a cytoplasmic phosphatase (c) Blockade of interleukin – 2- receptors (d) Inhibition of phospholipase A2 (e) Suppression of bone marrow progenitors

Last Answer : Ans: B

Description : Anyone else terrified of taking antibiotics? How do you cope?

Last Answer : KEEP TAKING IT! If the bad bacteria in your system doesn’t get killed off by the antibiotics you’re taking, they could come back stronger that ever! So strong that no antibiotic will kill them and then they will kill YOU!!! So KEEP TAKING IT like the good doctor said!!!

Description : Anyone else scared of taking antibiotics due to reactions?

Last Answer : Every single freaking thing you put in your mouth can have side effects. No, I’m not going to beat myself up over something so unlikely to happen.

Description : Had anyone got rid of strep throat without taking antibiotics?

Last Answer : I’ve had them on and off since I had mono in junior high. I burn it out with scalding tea, then soothe with gargling salt water. Good luck. Go see a doctor though for real please.

Description : Do anti-vaxxers also eschew things like tetanus shots and antibiotics?

Last Answer : Some do I am sure. I am anti- OVER vaccinating, and this is why I won't be re-vaccinating my 7 and 10 yr. old cats that are indoors only at this time. They have enough immunity ... horses. Horses are highly susceptible to Tetanus, more so than other farm animals, though they are vaccinated as well.

Description : Antibiotics causing swollen lymph nodes under jawline?

Last Answer :

Description : Can a course of antibiotics leave you feeling very run down?

Last Answer : Absolutely.