When you take an antibiotic, it enters your bloodstream and travels through your body, killing bacteria but not human cells. There are few differences, however, between harmful and friendly bacteria. Antibiotics kill not only the bad bacteria making you sick, but also your resident friendly bacteria. Friendly bacteria help keep you healthy in many ways, so when antibiotics kill friendly bacteria, your health can suffer because you lose these benefits. Additionally, losing friendly bacteria can give other types of bacteria room to multiply, leading to opportunistic infection. Sometimes opportunistic infection happens when bacteria from the environment get into your body and overrun friendly bacteria damaged by an antibiotic. Other times opportunistic infection begins when antibiotics disturb the balance of your resident microbes, and normally friendly bacteria multiply too quickly and become harmful. One common cause of opportunistic infection is clostridium difficile (klos-TRID-e-uhm dif-uh-SEEL). Like many opportunistic bacteria, C. difficile live in the environment and do not normally harm healthy people. However, certain groups of people, like older adults who have been on antibiotics for a long time, are vulnerable. When antibiotics kill too many friendly bacteria in the intestine, C. difficile multiplies and produces toxins that make the person sick with symptoms like fever, nausea, diarrhea, and inflammation. 1 Who proposed the concept of chemotherapy, that compounds might selectively kill pathogens without harming people? 2 An antimicrobial that inhibits cell wall synthesis will result in which of the following? Cells become more susceptible to osmotic pressure 3 Beta-lactam antibiotics have an effect on which of the following types of cells? 4 Which of the following is a primary advantage of semisynthetic drugs? they have a broader spectrum of action 5 Which of the following drugs specifically targets cell walls that contain arabinogalactan-mycolic acid? 6 Which of the following antibiotics disrupts cytoplasmic membrane function? 7 Which of the following is NOT a target of drugs that inhibit protein synthesis? interference with alanine-alanine bridges 8 this figure represents a petri plate. the gray area is where bacteria A is growing, the black area is where bacteria B is growing. the white area is a zone where neither organism is growing. What is the best interpretation of what is observed on the plate? Bacteria B is producing an antibiotic that inhibits the growth of bacteria A. 9 Which of the following type of antimicrobial agent has the narrowest spectrum of action? 10 The first synthetic antimicrobial widely available for treatment of infections was an attachment antagonist 11 In the compound lamivudine an -SH group replaces an -OH group found in cytosine. When used as a medication it will interfere with nucleic acid synthesis 12 Which of the following groups of drugs can become incorporated into the bones and teeth of the fetus? 13 Which of the following can result when antibiotic therapy disrupts the normal microbiota? both pseudomembranous colitis and thrush 14 A compound is extracted from a microbial culture and is modified in the laboratory for use as an oral medication. this product would be a semisynthetic antimicrobial 15 B-lactamase production is an example of which of the following types of resistance? 16 Bacillus licheniformis secretes a compound that inhibits the growth of other Gram-positive bacteria. this is an example of an 17 Most drugs that inhibit the synthesis of the cell wall act by preventing the cross-linkage of NAM subunits. 18 Most broad spectrum antibiotics act by inhibiting protein synthesis 19 Which of the following antifungals works by inhibiting ergosterol synthesis? both fluconazole and turbinafine 20 A drug is structurally similar to PABA and inhibits folic acid synthesis. It is most likely a 21 Which of the following pathways is specifically inhibited by sulfonamides? the conversion of PABA to dihydrofolic acid 22 Which of the following drugs inhibits nucleic acid synthesis in prokaryotes? 23 The cooperative activity of drugs such as beta-lactam antibiotics and clavulanic acid, a B-lactamase inhibitor, is known as 24 Alterations in the structure of which of the following are an important aspect of Gram-negative bacterial resistance to antimicrobial drugs? 25 it is inappropriate to prescribe antibacterial agents to treat colds or flu becasue these diseases are caused by viruses 26 Who discovered the first antibiotic widely available to the general public? 27 Which of the following statements is true of selective toxicity? Selective toxicity takes advantage of structural differences between host and pathogen. 28 Antimicrobials that block protein synthesis by binding to the mRNA are 29 The E-test determines which of the following? both susceptibility and MIC(minimum inhibitory concentration) 30 The therapeutic range of an antimicrobial is the range of concentrations at which the antimicrobial is both effective and non-toxic 31 Which of the following interferes with cell wall synthesis by blocking alanine bridge formation? both cycloserine and vancomycin 32 Antimicrobial sugars analogs are effective for preventing virus attachment 33 Which of the following is a measurement associated with the broth dilution test? 34 Infection of the _____ would be the hardest to treat with antimicrobial drugs. 35 Disruption of the normal microbiota can result in infections caused by which of the following microbes? Candida albicans, Mycobacterium, and Clostridium difficile 36 The antimicrobials called quinolone act by inhibiting DNA replication 37 How does resistance to drugs spread in bacterial populations? Both horizontal gene transfer and the growth of biofilms spread drug resistance 38 The mechanism of action of the antibiotic vancomycin is inhibition of cell wall synthesis 39 The tetracyclines interfere with 40 Pentamidine is an example of an antimicrobial that 41 The mechanism of action of erythromycin is inhibition of protein synthesis 42 Methicillin is an example of the beta-lactam class of drugs that inhibits cell wall synthesis 43 Ribavirin is an antiviral that interferes with 44 The antimicrobial polymyxin disrupts cytoplasmic membranes 45 Drug resistant populations of microbes arise when exposure to drugs selectively kills sensitive cells, allowing overgrowth of resistant cells. 46 Any drug that acts against a disease is called a (analog/ antibiotic/ chemotherapeutic) agent. 47 Selective (toxicity/ action/ treatment) means that a given antimicrobial agent is more toxic to a pathogen than to the host being treated. 48 Nucleotide or nucleoside (analogs/ antisense/ acids) are antimicrobial agents that mimic the chemical structure of DNA building blocks. 49 A microbe resistant to a variety of different antimicrobials is said to have (cross/ drug/ multiple) resistance. 50 Secondary infections that result from the killing of some of the normal microbiota are called (antagonism/ superinfection/ resistance). 51 Competition between beneficial microbes and potential pathogens is called (synergy/ antagonism). 52 A (bacteriostatic/ bacteriocidal/ minimum) concentration of a drug is one at which microbes survive but are not able to grow and reproduce. 53 the ratio of a medication's dose that cane tolerated to its effective dose is the therapeutic (range/ index) of the medication. 54 Some bacteria develop resistance to groups of drugs because the drugs are all structurally similar to each other; this is a phenomenon known as (cross/ multiple) resistance. 55 Second generation drugs are semisynthetic drugs developed to combat (immunity/ resistance) against an existing drug. 56 Drugs that slow down bacterial growth would be (competitive/ synergistic/ antagonistic) to penicillin. 57 External infections can be treated by (surface/ topical) administration, in which a drug is applied directly to the site of infection. 58 the abbreviation (MIC/ MID/ MD) stands for the smallest amount of a drug that will inhibit the growth and reproduction of a pathogen. 59 Antiviral medication frequently block unique (proteins/enzymes/ molecules) to prevent production of new virus. 60 Some medications for influenza are (attachment/ binding/ microbial) antagonists that block the ability of the virus to enter cells. Which of the following structures is the target of betaβ-Lactam antibiotics inhibit bacteria by binding covalently to PBPs in the cytoplasmic membrane. These target proteins catalyze the synthesis of the peptidoglycan that forms the cell wall of bacteria.
What are betaBeta-lactam antibiotics are used in the management and treatment of bacterial infections.
Why does betaWhy do the beta-lactam drugs affect bacteria but NOT human cells? The beta-lactam antibiotics act on bacterial cell walls; human cells do not have cell walls.
Why are βBeta-lactam antibiotics kill sensitive bacteria by inactivating key enzymes involved in cell wall synthesis, termed penicillin-binding proteins. The specific beta-lactam agents have different half-lives, but all demonstrate time-dependent killing [1].
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