Mechanisms of Antibiotics Resistance
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What is the primary origin of antibiotics?

  • Soil animals
  • Human tissues
  • Soil bacteria and fungi (correct)
  • Plant cells

    • What is the primary concern with antibiotic resistance?

  • Increased effectiveness against gram-negative bacteria
  • Reduced toxicity to humans
  • Difficulty in treating infections (correct)
  • Increased production of antibiotics

    • Which bacterial strain's resistance to penicillin is an example of antibiotic resistance?

  • Streptococcus pneumoniae (correct)
  • Streptococcus aureus
  • E. coli
  • Staphylococcus aureus

    • What was the first antibiotic discovered?

    <p>Penicillin</p> Signup and view all the answers

    What is the outcome of antibiotic resistance among bacterial pathogens?

    <p>Infections are harder to treat</p> Signup and view all the answers

    What is the result of the development of thousands of antibiotic variants and analogues?

    <p>Varying effects on different infectious organisms and less toxicity to humans</p> Signup and view all the answers

    What is the primary function of efflux pumps in bacterial cells?

    <p>To remove noxious compounds from the cytoplasm</p> Signup and view all the answers

    Which of the following efflux pump systems is responsible for multiple antibiotics and toxic compounds in Neisseria gonorrhoeae?

    <p>MtrCDE system</p> Signup and view all the answers

    What is the energy source used by efflux pumps to transport substrates?

    <p>Proton motive force (PMF)</p> Signup and view all the answers

    Which of the following is a characteristic of the NorA pump in Staphylococcus aureus?

    <p>It provides resistance to a range of structurally unrelated antibiotics</p> Signup and view all the answers

    What is the role of the periplasmic protein in efflux pumps?

    <p>To connect the efflux pump to the outer membrane protein</p> Signup and view all the answers

    What is the result of the overexpression of an efflux pump gene in a bacterium?

    <p>A multiple antibiotic resistance phenotype</p> Signup and view all the answers

    Which of the following is a mechanism of action of efflux pump systems?

    <p>Catalyzing the active transport of substrates</p> Signup and view all the answers

    What is the role of the outer membrane protein in efflux pumps?

    <p>To form a channel through the periplasm and outer membrane</p> Signup and view all the answers

    How many families of efflux pumps have been described in microorganisms?

    <p>Five</p> Signup and view all the answers

    What is the function of the MtrR protein in Neisseria gonorrhoeae?

    <p>To repress the expression of MtrCDE</p> Signup and view all the answers

    What is the main reason why efflux is undesirable for organisms trying to treat infections?

    <p>It prevents the effective concentration of antibiotics at the site of infection</p> Signup and view all the answers

    What is the primary function of beta-lactamase enzymes produced by bacteria?

    <p>To break the beta-lactam ring of antibiotics</p> Signup and view all the answers

    What is the result of the action of erythromycin esterase (EreA) on macrolide antibiotics?

    <p>Hydrolytic cleavage of the lactone ring</p> Signup and view all the answers

    What is the difference between the Mpr strain and wild-type bacteria in terms of macrolide lincosamide and streptogramin B MLS antibiotics?

    <p>The Mpr strain has a point mutation that prevents MLS antibiotic binding</p> Signup and view all the answers

    What is the result of the modification of target enzymes by antibiotic-inactivating enzymes such as erythromycin esterases and β-lactamases?

    <p>Decreased antibiotic binding affinity</p> Signup and view all the answers

    What is the function of transpeptidase enzymes in relation to penicillin-like antibiotics?

    <p>To catalyze the acetylation of the antibiotic</p> Signup and view all the answers

    What is the reason why Flucloxacillin, a penicillin, was no longer effective against staphylococci?

    <p>It was inactivated by staphylococcal penicillinase</p> Signup and view all the answers

    What is the effect of enzymatic inactivation on antibiotics?

    <p>It makes antibiotics less effective</p> Signup and view all the answers

    What is the reason why MRSA super bacteria are resistant to penicillin-like antibiotics?

    <p>They have a low affinity for the B-lactam ring in penicillin</p> Signup and view all the answers

    What is the primary mechanism of resistance in Kmr bacteria against aminoglycoside antibiotics?

    <p>Phosphotransferase enzyme that inactivates aminoglycosides</p> Signup and view all the answers

    How does erythromycin resistant methylase prevent antibiotic binding?

    <p>By methylating the ribosomal target site</p> Signup and view all the answers

    What is the typical mechanism of high-level resistance to vancomycin in Enterococcus faecium?

    <p>Stepwise acetylation of cell wall precursors</p> Signup and view all the answers

    What is the role of biofilm formation in antibiotic resistance?

    <p>It renders antibiotics ineffective due to phenotypic changes</p> Signup and view all the answers

    What is the effect of aminoglycoside modifying enzymes on the antibiotic's ability to bind to the 30S subunit?

    <p>It decreases the antibiotic's affinity</p> Signup and view all the answers

    What is the mechanism of resistance in Enterococci against aminoglycosides?

    <p>Presence of aminoglycoside modifying enzymes</p> Signup and view all the answers

    What is the typical outcome of infection by vanA-containing isolates in Enterococcus faecium?

    <p>Treatment failure with vancomycin</p> Signup and view all the answers

    How does the acquisition of resistance genes contribute to biofilm resistance?

    <p>It provides high levels of drug tolerance</p> Signup and view all the answers

    What is the effect of high-affinity mechanisms on aminoglycoside uptake in P. aeruginosa biofilms?

    <p>It inhibits aminoglycoside uptake</p> Signup and view all the answers

    What is the mechanism of chloramphenicol inactivation by R-Plasmids?

    <p>Chloramphenicol acetyltransferase</p> Signup and view all the answers

    What is the primary reason for the inefficiency of antibiotics in penetrating biofilms?

    <p>Physicochemical interactions between the drug and the matrix</p> Signup and view all the answers

    What is the consequence of stepwise selection processes involving multiple genetic mutations in bacteria?

    <p>Bacteria become highly resistant to specific antibiotics while maintaining a level of resistance</p> Signup and view all the answers

    What is the relationship between biofilm organisms and the incidence of complete infection removal?

    <p>The proximity of resistance in biofilm organisms results in a lower incidence of complete infection removal</p> Signup and view all the answers

    What is the primary reason for the ineffective treatment of biofilm-related infections?

    <p>Impaired penetration of antibiotics into the biofilm</p> Signup and view all the answers

    What is the estimated cost of device-related infections in the USA?

    <p>Over $3 billion per year</p> Signup and view all the answers

    What is the primary mechanism of antibiotic resistance in biofilms?

    <p>Sequestration of antibiotics by the extracellular matrix</p> Signup and view all the answers

    What is the characteristic of biofilm cells that contributes to antibiotic tolerance?

    <p>Close-knit packing and slow growth due to nutrient limitation</p> Signup and view all the answers

    What is the function of efflux pumps in bacterial cells?

    <p>To recognize and transport antibiotics out of the cell</p> Signup and view all the answers

    What is the energy source used by efflux pumps to transport antibiotics?

    <p>ATP</p> Signup and view all the answers

    What is the primary function of the AcrAB-TolC efflux system in E. coli?

    <p>To recognize and expel various substrates</p> Signup and view all the answers

    What is the main mechanism of antibiotic resistance conferred by the QacA multidrug efflux pump in Staphylococcus?

    <p>Efflux of organic cationic compounds</p> Signup and view all the answers

    How does the SatAB efflux system in E. faecium contribute to high-level antibiotic resistance?

    <p>By both reducing drug uptake and effluxing antibiotics</p> Signup and view all the answers

    What is the mechanism of ribosomal protection in Bacillus?

    <p>Transfer of an ATP-binding ribosomal protein and phosphorylation of a hydrolytic enzyme</p> Signup and view all the answers

    How does the production of an alternative PBP with low affinity for beta-lactam compounds contribute to methicillin resistance?

    <p>By preventing amoxicillin from binding its target PBPs</p> Signup and view all the answers

    What is the function of the carbapenemase enzymes produced by certain Enterobacteriaceae?

    <p>To hydrolyze carbapenems to inactive metabolites</p> Signup and view all the answers

    What is the characteristic of the single drug/MF superfamily of efflux pumps?

    <p>Recognition of multiple unrelated drugs</p> Signup and view all the answers

    What is the role of the ATP-binding ribosomal protein in Bacillus?

    <p>To confer resistance to macrolides, lincosamines, and streptogramin B</p> Signup and view all the answers

    What is the consequence of dysfunctional AcrAB-TolC systems in E. coli?

    <p>Lower resistance to fluoroquinolones and inhibitor Phe-Arg β-naphthylamide</p> Signup and view all the answers

    What is the characteristic of the efflux systems used by bacteria to remove toxic substances and drugs?

    <p>Similarity to those in higher organisms</p> Signup and view all the answers

    What is one of the negative outcomes of antibiotic resistance mentioned in the text?

    <p>Permanent hearing loss in patients with pneumococcal meningitis</p> Signup and view all the answers

    What was the first antibiotic discovered, but its efficacy was not realized until a specific event?

    <p>Penicillin</p> Signup and view all the answers

    Which genetic mechanism of antimicrobial resistance involves acquiring genes from another microorganism?

    <p>Horizontal gene transfer</p> Signup and view all the answers

    What is the main reason behind the increased medical costs associated with antibiotic resistance?

    <p>Prolonged treatment durations</p> Signup and view all the answers

    Which type of antibiotics may alter the microbial ecology of the human body?

    <p>Broad-spectrum antibiotics</p> Signup and view all the answers

    What percentage of hospital admissions is attributed to adverse effects of antibiotic therapy?

    <p>10%</p> Signup and view all the answers

    What natural process has been influenced by human activity and has led to the proliferation of antimicrobial resistance?

    <p>Hybrid gene transfer</p> Signup and view all the answers

    Which event caused infectious diseases to not be eradicated as predicted by U.S. surgeons?

    <p>Misuse and overuse of antibiotics</p> Signup and view all the answers

    What change in a bacterium's DNA sequence can provide it with a selective advantage against antibiotics?

    <p>Mutation</p> Signup and view all the answers

    What impact has the unrestricted use of newer antibiotics had according to the text?

    <p>Economic consequences</p> Signup and view all the answers

    What is the key difference between transduction and conjugation in bacteria?

    <p>Transduction involves genes being transferred through bacteriophages, while conjugation involves genes being transferred through pili.</p> Signup and view all the answers

    How do bacteria become resistant to harmful substances at low frequencies?

    <p>By changing shape in just 20 minutes due to anamorphosis.</p> Signup and view all the answers

    What is the role of penicillinase in bacteria resistance?

    <p>It breaks down the -lactam vibratory of antibacterial drugs.</p> Signup and view all the answers

    How are efflux pump systems described in bacteria resistance to antibiotics?

    <p>They are chromosome-encoded elements that expel antibiotics from the cell.</p> Signup and view all the answers

    What initiates recombination during horizontal gene transfer between bacteria?

    <p>Physical contact between two bacteria of compatible mating types.</p> Signup and view all the answers

    How do efflux pump systems provide resistance to antibiotics in bacterial cells?

    <p>By expelling several structurally unrelated antibiotics from the cell.</p> Signup and view all the answers

    What do efflux pump systems need for energization to resist antibiotics in bacterial cells?

    <p>Proton motive force.</p> Signup and view all the answers

    What can happen if the efflux pump systems in bacteria are overexpressed?

    <p>It is often associated with mutations in repressor genes.</p> Signup and view all the answers

    How does DNA-mediated transformation differ from recombination during horizontal gene transfer between bacteria?

    <p>DNA-mediated transformation involves transferring naked DNA from one bacterium to another.</p> Signup and view all the answers

    Why is the study of efflux pump systems crucial for the continued effectiveness of antibiotics?

    <p>Understanding them can help develop efflux pump inhibitors to potentiate antibiotics.</p> Signup and view all the answers

    What is the primary consequence of antibiotic resistance among bacterial pathogens?

    <p>Increased difficulty in treating infections</p> Signup and view all the answers

    What is the main outcome of the discovery of antibiotics?

    <p>Major breakthrough in human health history</p> Signup and view all the answers

    Which type of bacteria are antibiotics effective against?

    <p>Gram-positive bacteria</p> Signup and view all the answers

    What is the reason behind the varying effects of antibiotics on different infectious organisms?

    <p>The development of thousands of variants and analogues</p> Signup and view all the answers

    What is the result of the evolution of bacteria to be resistant to most or all available antibiotics?

    <p>Infections becoming harder to treat and increasing the likelihood of spreading to others</p> Signup and view all the answers

    What is the example of antibiotic resistance mentioned in the text?

    <p>Streptococcus pneumoniae's resistance to penicillin</p> Signup and view all the answers

    What is the main consequence of the misuse and overuse of antibiotics?

    <p>The evolution of antibiotic-resistant bacteria</p> Signup and view all the answers

    What is the primary function of antibiotics?

    <p>To inhibit the growth of bacteria</p> Signup and view all the answers

    What is the result of the emergence of antibiotic-resistant bacteria in hospitals?

    <p>Increased medical costs</p> Signup and view all the answers

    What is the significance of studying antibiotic resistance?

    <p>To address the negative consequences of antibiotic therapy</p> Signup and view all the answers

    What is the main mechanism of antibiotic resistance?

    <p>Mutation and gene transfer</p> Signup and view all the answers

    What is the consequence of the unrestricted use of newer antibiotics?

    <p>Economic consequences</p> Signup and view all the answers

    What is the impact of antibiotic resistance on the treatment of pneumococcal meningitis?

    <p>Increased treatment failures</p> Signup and view all the answers

    What is the natural process that has been influenced by human activity and has led to the proliferation of antimicrobial resistance?

    <p>Horizontal gene transfer</p> Signup and view all the answers

    What is the result of the overuse of penicillin for streptococcal pneumonia treatment?

    <p>The emergence of antibiotic-resistant bacteria</p> Signup and view all the answers

    What is the consequence of antibiotic resistance on the natural history of diseases?

    <p>The creation of new problems</p> Signup and view all the answers

    What is the primary mechanism of horizontal gene transfer between bacteria that involves the exchange of genetic material through direct cell-to-cell contact?

    <p>Recombination</p> Signup and view all the answers

    What is the primary function of the enzyme penicillinase produced by some bacteria?

    <p>To break down the lactam ring of antibacterial drugs</p> Signup and view all the answers

    What is the characteristic of efflux pump systems that allows them to expel multiple structurally unrelated antibiotics from the cell?

    <p>Broad substrate specificity</p> Signup and view all the answers

    What is the primary mechanism of genetic change that increases the effectiveness of antibiotics against bacteria?

    <p>Genetic mutation that causes the bacteria to attack the agent</p> Signup and view all the answers

    What is the primary role of plasmid transfer in horizontal gene transfer?

    <p>To transfer genetic material through a mobile genetic element</p> Signup and view all the answers

    What is the primary mechanism of antibiotic resistance conferred by efflux pump systems?

    <p>Expelling the antibiotic from the cell</p> Signup and view all the answers

    What is the primary mechanism of action of DNA-mediated transformation in horizontal gene transfer?

    <p>Transferring genetic material through naked DNA</p> Signup and view all the answers

    What is the primary reason why efflux pump systems are a major concern in the development of antibiotics?

    <p>They can lead to multidrug resistance</p> Signup and view all the answers

    What is the primary mechanism of genetic change that allows bacteria to become resistant to harmful substances at low frequencies?

    <p>Anamorphosis and change in shape</p> Signup and view all the answers

    What is the primary mechanism of recombination in horizontal gene transfer?

    <p>Transferring genetic material through direct cell-to-cell contact</p> Signup and view all the answers

    What is the primary function of the periplasmic protein or adaptor in efflux pumps?

    <p>To connect the efflux pump to the outer membrane protein</p> Signup and view all the answers

    Which of the following efflux pump systems is responsible for the transport of tetracycline out of bacterial cells?

    <p>TetA system</p> Signup and view all the answers

    What is the result of the overexpression of an efflux pump gene in a bacterium?

    <p>Multiple antibiotic resistance phenotype</p> Signup and view all the answers

    What is the energy source used by efflux pumps to transport substrates?

    <p>Proton motive force (PMF)</p> Signup and view all the answers

    Which of the following is a characteristic of the RND efflux pump system?

    <p>It spans both the inner and outer membranes of the bacteria</p> Signup and view all the answers

    What is the primary function of efflux pumps in bacterial cells?

    <p>To maintain a less toxic intracellular environment</p> Signup and view all the answers

    Which of the following is an example of an efflux pump system that is responsible for multiple antibiotics and toxic compounds?

    <p>MtrCDE system</p> Signup and view all the answers

    What is the role of the MtrR protein in Neisseria gonorrhoeae?

    <p>To regulate the expression of the MtrCDE operon</p> Signup and view all the answers

    Which of the following efflux pump systems is responsible for the removal of quinolones, hydrophilic β-lactams, erythromycin, and tetracycline from Staphylococcus aureus?

    <p>NorA system</p> Signup and view all the answers

    What is the consequence of the overexpression of an efflux pump gene or alteration to the pump or its regulators in a bacterium?

    <p>Multiple antibiotic resistance phenotype</p> Signup and view all the answers

    What is the primary mechanism of resistance to macrolide antibiotics in Gram-positive and Gram-negative species?

    <p>Action of erythromycin esterase (EreA) catalyzing the hydrolytic cleavage of the lactone ring</p> Signup and view all the answers

    What is the target of beta-lactamase enzymes produced by bacteria?

    <p>The beta-lactam ring of penicillins, cephalosporins, and carbapenems</p> Signup and view all the answers

    What is the result of the modification of target enzymes by antibiotic-inactivating enzymes such as erythromycin esterases and β-lactamases?

    <p>A weak positive selection process under antibiotic conditions</p> Signup and view all the answers

    What is the primary function of clavulanic acid in the treatment of bacterial infections?

    <p>To inhibit the action of beta-lactamase enzymes</p> Signup and view all the answers

    What is the characteristic of the Mpr strain in terms of macrolide lincosamide and streptogramin B MLS antibiotics?

    <p>It has a point mutation that prevents MLS antibiotic binding</p> Signup and view all the answers

    What is the primary mechanism of enzymatic inactivation of antibiotics?

    <p>Enzymatic modification of the antibiotic structure</p> Signup and view all the answers

    What is the primary reason for the development of antibiotic resistance in bacteria?

    <p>To survive in the presence of antibiotics</p> Signup and view all the answers

    What is the role of transpeptidase enzymes in bacterial resistance to penicillin-like antibiotics?

    <p>To split the complex before acetylating the antibiotic</p> Signup and view all the answers

    What is the primary mechanism of antibiotic resistance conferred by the Erm genes?

    <p>Erythromycin ribosome methylation</p> Signup and view all the answers

    What is the primary reason for the persistence of infections in biofilms?

    <p>The impaired penetration of antibiotics</p> Signup and view all the answers

    What is the result of the stepwise selection process involving multiple genetic mutations in bacteria?

    <p>The maintenance of a level of resistance to specific antibiotics</p> Signup and view all the answers

    What is the primary mechanism of antibiotic resistance in biofilms?

    <p>The sequestration of antibiotics by the extracellular matrix</p> Signup and view all the answers

    What is the significance of the rifampicin gene in antibiotic resistance?

    <p>It results in strains having only planktonic or biofilm resistance to rifampicin</p> Signup and view all the answers

    What is the characteristic of biofilm cells that contributes to antibiotic tolerance?

    <p>Slow growth rate due to nutrient limitation</p> Signup and view all the answers

    What is the energy source used by efflux pumps to transport antibiotics?

    <p>ATP</p> Signup and view all the answers

    What is the significance of the polysaccharide intercellular adhesion in staphylococcal biofilms?

    <p>It acts as a barrier to antimicrobial agents</p> Signup and view all the answers

    What is the consequence of the selection of inappropriate antibiotics in treating biofilm infections?

    <p>The increased resistance of bacteria to antibiotics</p> Signup and view all the answers

    What is the estimated cost of device-related infections in the USA?

    <p>Over $3 billion per year</p> Signup and view all the answers

    What is the primary reason for the high antibiotic dose strategies being less preferred in treating biofilm infections?

    <p>The increased risk of side effects and drug toxicity</p> Signup and view all the answers

    What is the characteristic of the single drug/MF superfamily of efflux pumps in bacteria?

    <p>They can confer resistance to several unrelated drugs due to their varying size, charge, and chemical composition.</p> Signup and view all the answers

    Which of the following efflux pumps is capable of recognizing and expelling various substrates, including quaternary ammonium compounds, antiseptics, and dyes?

    <p>QacA</p> Signup and view all the answers

    What is the mechanism of methicillin resistance in MRSA isolates and S. pneumoniae isolates?

    <p>Production of an alternative PBP with low affinity for beta-lactam compounds.</p> Signup and view all the answers

    Which of the following is NOT a characteristic of the AcrAB efflux system in E. coli?

    <p>It is plasmid-mediated and can be transferred between bacterial species.</p> Signup and view all the answers

    What is the mechanism of antibiotic resistance in Bacillus through ribosomal protection?

    <p>Transfer of an ATP-binding ribosomal protein and phosphorylation of a hydrolytic enzyme.</p> Signup and view all the answers

    What is the consequence of dysfunctional AcrAB-TolC systems in E. coli?

    <p>Decreased resistance to fluoroquinolones and inhibitor Phe-Arg β-naphthylamide.</p> Signup and view all the answers

    What is the function of the carbapenemase enzymes produced by certain Enterobacteriaceae?

    <p>To hydrolyze carbapenems to inactive metabolites.</p> Signup and view all the answers

    Which of the following efflux pumps is responsible for high-level resistance to many antibiotics in E. faecium?

    <p>SatAB</p> Signup and view all the answers

    What is the energy source used by efflux pumps to transport substrates across the cellular membrane?

    <p>Either ATP or a chemiosmotic gradient</p> Signup and view all the answers

    What is the result of antibiotic modification by antibiotic-inactivating enzymes such as beta-lactamases?

    <p>Prevention of antibiotic binding to the target enzyme.</p> Signup and view all the answers

    What is a common mechanism used by bacteria to resist antibiotics by making them ineffective in targeting the ribosome?

    <p>Ribosomal protection</p> Signup and view all the answers

    Which enzyme produced by some bacteria catalyzes the methylation of the ribosomal target site of erythromycin, leading to antibiotic resistance?

    <p>Erythromycin resistant methylase</p> Signup and view all the answers

    What leads to reduced affinity and bactericidal activity of aminoglycosides in bacteria?

    <p>Ribosomal protection</p> Signup and view all the answers

    In which case does a specific microbial mechanism inhibit aminoglycoside uptake in P. aeruginosa biofilms?

    <p>Iron-transport system downregulation</p> Signup and view all the answers

    Which modification alters the binding site of fosfomycin, rendering it ineffective against bacteria?

    <p>UDP-N-acetylglucosamine enolpyruvyl transferase modification</p> Signup and view all the answers

    What is a common strategy employed by bacteria to decrease the binding affinity of antibiotics to the ribosome?

    <p>Ribosomal protection</p> Signup and view all the answers

    Which enzyme is responsible for the inactivation of chloramphenicol in R-Plasmids and the antibiotic itself?

    <p>Chloramphenicol acetyltransferase</p> Signup and view all the answers

    What is a mechanism that bacteria use to resist antibiotics by altering the cell wall precursor, usually leading to low-level resistance?

    <p>Cell wall precursor alteration</p> Signup and view all the answers

    Which bacterial resistance mechanism involves stepwise acetylation of cell wall precursors by enzymes encoded by van genes?

    <p>Biofilm formation</p> Signup and view all the answers

    What is the primary action of aminoglycoside modifying enzymes in bacteria that reduce antibiotic effectiveness?

    <p>30S subunit binding inhibition</p> Signup and view all the answers

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