NURS 5334 Antimicrobial Principles Detailed Exam 2026

NURS 5334 Antimicrobial Principles Detailed Exam 2026 Antibiotic - -A chemical secreted by a living organism that kills or reduces the reproduction rate of other organisms Antimicrobial - -Any agent of a natural or synthetic that can kill or suppress micro organisms Antimicrobial drugs classification by susceptible organism - -Narrow-spectrum antibiotics (preferred) Broad-spectrum antibiotics Classified by mechanism of action - -Drugs that work on cell wall synthesis Drugs that increase cell membrane permeability Drugs that cause lethal inhibition of bacterial protein synthesis Drugs that cause non-lethal inhibition of protein synthesis Drugs that inhibit bacterial synthesis of DNA and RNA, or disrupt DNA function Anti-metabolites Drugs that suppress viral replication Drugs that inhibit cell wall synthesis - -Penicillins and cephalosporins Weaken cell wall, hence promote bacterial lysis and death Drugs that increase cell membrane permeability - -Amphotericin B Increase the permeability of cell membranes causing leakage of intracellular material Drugs that cause lethal inhibition of bacterial protein synthesis - -Aminoglycosides; gentamicin Drugs that cause non-lethal inhibition of protein synthesis - -Tetracyclines Inhibit bacterial protein synthesis, and only slow microbial growth, but do not kill the bacteria at clinically achievable concentrations Drugs that inhibit bacterial synthesis of DNA and RNA, or disrupt DNA function - Rifampin, metronidazole, and fluoroquinolones Binding directly to the nucleic acids or by interacting with enzymes required for nucleic acid synthesis, and can also bind with DNA and disrupt its function Anti-metabolites - -Trimethoprim and sulfonamides NURS 5334 NURS 5334 Disrupt specific biochemical reactions, and this result is either a decrease in the synthesis of essential and constituents or a synthesis of nonfunctional analogs of minimal metabolites Drugs that suppress viral replication - -inhibit specific enzymes, either DNA, polymerase reverse transcriptase protease, integrase, or neuraminidase, which are required in viral replica Bactericidal drugs - -Directly lethal to the bacteria at clinically achievable concentrations Bacteriostatic - -Slow bacterial growth, but do not cause cell death Organisms that are once highly sensitive to an antibiotic may become less susceptible or lose drug sensitivity entirely, and resistance develops Organisms with drug resistance - -Enterococcus, Staphylococcus aureus, Pseudomonas, Acinetobacter, Klebsiella, and Clostridium difficile Four basic actions of microbial mechanisms for drug resistance - -1. Reduction of drug concentration at the site of its action (usually intracellular) 2. Alteration of drug target molecules (receptors) 3. Antagonist production 4. Drug inactivation (by bacterial enzymes) - beta-lactam ring in beta-lactamase producers Mechanisms for acquired resistance - -1. Spontaneous mutations 2. Conjugation Spontaneous mutations - -Mutation produces random changes in a microbe's DNA, resulting is a gradual increase in resistance Confer resistance only to one single drug Conjugation - -Extrachromosomal DNA is transferred from one bacterium to another, carrying resistances DNA Broad-spectrum antibiotics in drug resistance - -Broad-spectrum antibiotics kill more competing organisms than narrow-spectrum, the broad-spectrum agents do the most to facilitate emergence of resistance Healthcare-associated infections - -Can be highly difficult to treat because hospitals are sites of intensive antibiotic use Super infection - -A new infection that appears during the course of treatment for a primary infection While antibiotics eliminate the inhibitory influence of normal flora, a second infectious agent flourish NURS 5334 NURS 5334 Delay the emergence of drug-resistance - -Promote appropriate prescribing guidelines Limit prescriptions in healthy adults Emphasize drug adherence Public Health Action Plan to Combat Antimicrobial Resistance - -CDC Surveillance, prevention, control, research, and product development Organizations to combat antimicrobial resistance - -The Infectious Disease Society of America, Society for Healthcare Epidemiology, and Pediatric Infectious Disease Society, the American Board of Internal Medicine Foundation who created the Choosing Wisely campaign to decrease the amount of wasteful practice in healthcare Get Smart for Healthcare, initiated by the CDC Selecting antibiotic - -Identify the infecting organism Consider drug sensitivity of the infecting organism (match drug with the bug), host factor, such as site of infection, host defense status, allergy, heightened susceptibility of the patient to toxicity with the first drug choice Also potentially consider genetic heritage Empiric therapy - -Treatment of an infection before specific culture information has been reported or obtained Used in severe infections A broad-spectrum agent as initial treatment, a narrow-spectrum antibiotic can be used after result of culture and the drug sensitivity Polymerase chain reaction test, or nucleic acid amplification tests - -These can detect very low titers of bacteria and viruses, and testing is done using an enzyme, either a DNA polymerase or an RNA polymerase to generate thousands of copies of the DNA or RNA unique to the infecting microbe Testings to determine drug susceptibility - -A disk diffusion test, serial dilution, or a gradient diffusion test Giving penicillin in patients with unsure severity of allergy - -Skin testing to determine whether or not that patient has a true allergic reaction to penicillin Deficiency of glucose-6-phosphate dehydrogenase - -Can be the cause hemolysis patients who receive sulfonamides Dosage and duration of treatment - -The success requires that an antibiotic be present at the site of infection in the effective concentration for a sufficient amount of time Drug concentrations must be equal to or greater than the MIC for the infection being treated; drug levels of four to eight times of the MIC are the desirable levels Antibiotic combinations - -Two antibiotics are used together, it can result in the effect being additive, potentiative, or in certain cases antagonistic NURS 5334 NURS 5334 Potentiative interaction - -The effect of the combination is greater than the sum of the effects of the individual agents Antagonistic interaction - -For example, a bacteriostatic agent such as tetracycline combined with a bactericidal drug such as penicillin Used in a cases with severe infection with unknown etiology Mixed infections; multiple infectious organisms infection - -Brain abscesses and pelvic infections, abdominal perforations Require multiple antimicrobials Tuberculosis - -Drug combinations are used for suppressing the emergence of resistant bacteria Disadvantages of antibiotic combinations - -Increased risk for toxic and allergic reactions. Also possible, an antagonism of the antimicrobial effects, increased risk for super infection, and selection of drug-resistant bacteria, and expensive Prophylactic antibiotics - -Surgery; orthopedic, GI, appies, hysterectomies, etc. Prophylactic antibiotics to prevent the bacterial endocarditis Patients with neutropenia Recurrent UTIs; trimethoprim sulfamethoxazole Postcoital UTIs; after intercourse Misuses of antimicrobial drugs - -Prescribing in viral infections Most upper respiratory infections are viral and do not need to be treated with antibiotics Fever of unknown origin; only initiate antibiotic in severely immunocompromised patients Limitation of antimicrobials - -Antibiotics may have a limited efficacy in the present of foreign material or necrotic tissue or exudate Surgical procedures can promote efficacy Important clinical indicators - -Reduction of fever, resolution of signs and symptoms related to affected organ systems, and laboratory results Success of therapy is indicated by the disappearance of an infectious organism from post-treatment cultures The purpose of monitoring serum drug levels - -To ensure that therapeut