Antibiotics NCLEX Questions & Rationales with complete solutions

Antibiotics NCLEX Questions & Rationales with complete solutions An antimicrobial medication that has selective toxicity has which characteristic? A. Ability to transfer DNA coding B. Ability to suppress bacterial resistance C. Ability to avoid injuring host cells D. Ability to act against a specific microbe C. Ability to avoid injuring host cells Selective toxicity refers to an antibiotic that has the ability to injure only invading microbes, not the host. Conjugation is the process through which DNA coding for drug resistance is transferred from one bacterium to another. Antibiotics do not suppress bacterial resistance, but rather promote the emergence of drug-resistant microbes. Antibiotics that are narrow spectrum are active against only a few microbes. The development of a new infection as a result of the elimination of normal flora by an antibiotic is referred to as what? A. Resistant infection B. Superinfection C. Nosocomial infection D. Allergic reaction B. Superinfection Antibiotic therapy can destroy the normal flora of the body, which normally would inhibit the overgrowth of fungi and yeast. When the normal flora is decreased, these organisms can overgrow and cause a new infection, or superinfection. 00:30 01:09 A microbe acquires antibiotic resistance by which means? A. Development of medication resistance in the host B. Over-riding of the minimum bactericidal concentration C. Incorrect dosing, which contributes to ribosome mutations D. Transfer of DNA coding to other bacteria D. Transfer of DNA coding to another bacteria All alterations in structure and function result from changes in the microbial genome. The microbe, not the host, becomes medication resistant. Genetic changes in a microbe result either from spontaneous mutation or from acquisition of DNA from conjugation with other bacteria. The minimum bacterial concentration (MBC) is used in testing for drug sensitivity. Incorrect dosing does not lead to microbe mutations. The nurse identifies which host factor as the most important when choosing an antimicrobial drug? A. Age B. Competent immune function C. Genetic heritage D. Previous medication reactions B. Competent immune function Two factors—host defenses and the site of infection—are unique to the selection of antibiotics. It is critical for success that antibiotics act synergistically with the immune system to subdue infection. Other host factors, such as age, genetic heritage, and previous drug reactions, are the same factors that must be considered when choosing any other medication. What is the minimum bactericidal concentration (MBC)? A. The lowest concentration of an antibiotic needed to suppress bacterial growth completely B. The lowest concentration of an antibiotic needed to reduce the number of bacterial colonies by 99.9% C. The lowest concentration of an antibiotic needed to produce effects D. The lowest dose of an antibiotic needed to eradicate bacteria B. The lowest concentration of an antibiotic needed to reduce the number of bacterial colonies by 99.9% The MBC is the lowest concentration of drug that produces a 99.9% decline in the number of bacterial colonies (indicating bacterial kill). The lowest antibiotic concentration needed to suppress bacterial growth or to produce effects and the lowest antibiotic dose needed to eradicate bacteria are incorrect descriptions of MBC. Which test is the most widely used method for assessing drug sensitivity? A. Minimum inhibitory concentration (MIC) B. Minimum bacterial concentration (MBC) C. Broth dilution D. Disk diffusion D. Disk diffusion The most widely used method for assessing drug sensitivity is the disk diffusion test, also known as the Kirby-Bauer test. Through diffusion, an antibiotic-containing zone becomes established around each disk. As the bacteria proliferate, growth is inhibited around the disks that contain an antibiotic to which the bacteria are sensitive. A nurse removes a central line access device once the patient no longer requires intravenous (IV) antibiotics. This action is an example of which strategy to prevent antimicrobial resistance established by the Centers for Disease Control and Prevention (CDC)? A. Preventing transmission B. Proper diagnosis C. Preventing infection D. Prudent antibiotic use C. Preventing infection The CDC's campaign to prevent the development of antimicrobial resistance in hospitals focuses on four approaches: (1) prevent infection, (2) diagnose and treat infection effectively, (3) use antimicrobials wisely, and (4) prevent transmission. Expeditious removal of invasive devices, such as IV catheters, and restricting these devices to essential use are examples of the CDC's strategy to prevent infection. The nurse identifies what as the first step in the Campaign to Prevent Antimicrobial Resistance, established in 2002 by the CDC? A. Target the pathogen B. Access the experts C. Isolate the pathogen D. Vaccinate D. Vaccinate Although all responses are components of the Campaign to Prevent Antimicrobial Resistance, step one is vaccination. A patient has acquired an infection while in the hospital. The nurse identifies this type of infection as what? A. Superinfection B. Suprainfection C. Nosocomial infection D. Resistant infection C. Nosocomial infection Nosocomial infections are acquired by patients while in the hospital. Superinfection and suprainfection are terms used to describe the emergence of drug resistance. A nurse is assessing the effects of antimicrobial therapy in a patient with pneumonia. The nurse should establish which outcomes when planning care? (Select all that apply.) A. Potassium level of 4 mEq/dL B. Reduction of fever C. Sterile sputum cultures D. Oxygen saturation of 98% E. Elastic skin turgor B. Reduction of fever C. Sterile sputum cultures D. Oxygen saturation of 98% Antimicrobial therapy is assessed by monitoring clinical and laboratory responses. Clinical indicators of success in a patient with pneumonia may include afebrile status and resolution of an infectious infiltrate, resulting in an oxygen saturation above 95%. The disappearance of infectious organisms from post-treatment cultures also indicates resolution of infection. Potassium levels and elastic skin turgor are not assessment parameters for clinical infections, including pneumonia. Which are examples of the improper use of antibiotic therapy? (Select all that apply.) A. Using surgical drainage as an adjunct to antibiotic therapy B. Treating a viral infection C. Basing treatment on sensitivity reports D. Treating fever in an immunodeficient patient E. Using dosing that results in a superinfection B. Treating a viral infection E. Using dosing that results in a superinfection Common misuses of antibiotics include (1) treatment of a viral infection, which results in exposure of the patient to the risks of the medication without providing any benefits; and (2) improper dosing (dosing that is too high results in superinfection). The other answers are examples of the proper use of antimicrobial therapy. A nurse should recognize that antibiotic prophylaxis is appropriate in patients with which medical conditions? (Select all that apply.) A. Aortic valve replacement B. Ruptured appendix C. Bronchitis D. Neutropenia E. Chickenpox A. Aortic valve replacement D. Neutropenia Antibiotic prophylaxis is appropriate and effective in certain situations. These include patients who have prosthetic valves and are at risk for bacterial endocarditis. The use of antibiotics in "dirty" surgeries, such as those for ruptured organs, is considered treatment, not prophylaxis. Severe neutropenia can put patients at risk for severe infection, and antibiotics can reduce infections but may encourage fungal invasion. Antibiotics are not prescribed preventively for bronchitis or chickenpox.