Module 3 Review PDF

**MODULE 3: Antimicrobials** **[Key Terms]** **bactericidal:** substance that causes the death of bacteria, usually by interfering with cell membrane/wall stability or with proteins or enzymes necessary to maintain the cellular integrity of the bacteria **bacteriostatic:** substance that prevents...

**MODULE 3: Antimicrobials** **[Key Terms]** **bactericidal:** substance that causes the death of bacteria, usually by interfering with cell membrane/wall stability or with proteins or enzymes necessary to maintain the cellular integrity of the bacteria **bacteriostatic:** substance that prevents the replication of bacteria, usually by interfering with proteins or enzyme systems necessary for reproduction of bacteria **prophylaxis:** treatment to prevent an infection before it occurs (typically reserved for at risk patients in certain situations, not widely used) **resistance:** ability of pathogens over time to adapt to an anti-infective to produce cells that are no longer affected by a particular drug **spectrum:** range of bacteria against which an antibiotic is effective (i.e. broad spectrum antibiotics are effective against a wide range of bacteria, while narrow spectrum antibiotics are effective only against very selective bacteria) **superinfection:** infections that occur when opportunistic pathogens that were kept in check by the "normal" bacteria have the opportunity to invade tissues & cause infections because the normal flora bacteria have been destroyed by antibiotic therapy **[Foundational Info About Antibiotics]** Diagram Description automatically generated - Overall goal is to interfere with the normal function of the invading bacteria in order to prevent it from reproducing and to in some cases cause cell death, ideally without affecting host cells **Bactericidal vs. Bacteriostatic**  - Typically, bactericidal antibiotics interfere with the cell wall or cellular membrane of the bacteria, which prevents their ability to maintain cellular integrity... they burst! - Bacteriostatic antibiotics often prevent the bacteria from replicating further, but they rely on a functioning immune system to eradicate the infection... **very important to remember!** **Antibiotic Resistance** Image result for ways to reduce antibiotic resistance **Different ways antibiotic resistance can develop:** 1. Restricting access of antibiotic a. Some bacteria develop ability to change or limit the \# of entryways into cells so the antibiotic cannot get to where it needs to in order to work 2. Getting rid of the antibiotic b. Some bacteria literally pump the antibiotics out of the cells through pumps they insert in the cell walls, which flushes the antibiotics out before they can work 3. Changing or destroying the antibiotic c. Some bacteria use enzymes to change or break down the antibiotic, which renders it ineffective 4. Changing the target of the antibiotic d. Most antibiotics are designed to target specific parts of the bacteria, so if the bacteria change the target in a way that the antibiotic no longer is able to bind there then it becomes ineffective 5. Bypassing the effects of the antibiotic e. Some bacteria develop new processes where they don't need to use whatever the target of the antibiotic is in order to function, so the antibiotic's effects aren't very problematic for them  - Nurses play an important role in preventing development of antibiotic resistance... be cognizant of these strategies and educate your patients! **Gram Stains of Bacteria** Image result for gram positive vs gram negative - Differences in the peptidoglycan cell walls (gram + bacteria have thicker cell walls) & the outer membrane (only gram - bacteria have this) are what impact how they stain in the lab - Gram + stain purple, gram - stain pink **[My Approach to Antibiotics]** 1. Where is the infection in the body 2. What kinds of organisms tend to live there (gram + vs. gram -) 3. Which antibiotics cover those kinds of organisms (use spectrum chart) 4. Consider how "sick" the patient is (will help determine how broad of a drug(s) you should start with until cultures come back) 5. Know key nursing considerations for antibiotic chosen (how it works, common & potentially dangerous side effects, contraindications, patient teaching, important labs to monitor) \*\*\* ***Find a system that works for you and always follow it***... that process will help you choose antibiotics a lot more than mass memorizing every side effect, contraindication, etc. **Where is the Infection in the Body** - Pay attention to presenting clinical signs & what patient reports to you - *Do they have:* - Respiratory symptoms... cough, sputum production, fever, difficulty breathing - Urinary tract symptoms... painful urination, cloudy/foul-smelling urine, fever - Signs of sepsis (infection has entered bloodstream)... tachycardia, fever, hemodynamic instability, sometimes respiratory failure, poor urine output, extreme fatigue, confusion, poor perfusion - Remember though that it's not always clear where the infection is coming from (and sometimes the patient won't be able to tell you, like with pediatrics for example) **Where Do Bacteria Tend to Grow**  - *As a general rule...* - Gram + bacteria *mostly* live **above the diaphragm** and tend to be found in the skin and in mucous membranes in the nose, mouth, respiratory tract, and vagina - Gram - bacteria *mostly* live **below the diaphragm** and tend to be found in the GI & GU tract - Knowing where bacteria tend to grow can give you a good idea of what you are dealing with when a patient presents with a localized infection... it's a starting point - ***Always culture before you start antibiotic therapy!*** **Antibiotic Spectrum Chart** - You want to choose the narrowest spectrum antibiotic that will treat whatever bacteria is causing the infection - The hard part is... [you won't know right away] (need to wait for cultures to come back), so what do you do in the meantime? - Sometimes if the patient is not terribly sick, you could wait to start therapy until preliminary culture results come back - More often than not though, patients will be started on an empiric antibiotic until the species is identified on the culture - **"Sick" vs. "not sick"** often dictates how broad the empiric antibiotics need to be... then we narrow down once the cultures are back (so long as the patient is stable) **Culture & Sensitivity Report**  - This is an example culture & sensitivity report from a urine culture - Note that you don't get all of the information you need right away... it takes a few days for the bacteria to grow and for the lab to run testing on it with different antibiotics - As the results come back, re-evaluate the empiric antibiotics and make sure they are covering what this patient is growing - Use sensitivity report to select the lowest MIC values for drugs that are susceptible (listed as S)... a lower MIC means less of the drug is needed to kill the bacteria - **Be sure to consider practicality of the various options**... is it an IV only drug, is it broader than what is needed given the status of the patient (how "sick" they seem), cost can be a consideration also **[Antibiotic Drug Families]** **Aminoglycosides** (ex. gentamicin) - Bactericidal, **broad spectrum** (gram - coverage) - [Indications for use:] used to treat serious gram - infections (typically intra-abdominal or urinary tract) (see coverage chart for specific organisms) - [Contraindications & cautions:] pre-existing renal disease or hearing loss, hepatic disease - [Key adverse effects:] **ototoxicity** (can lead to irreversible deafness), **nephrotoxicity** (can cause progressive renal failure), GI effects, hepatic toxicity, rare cardiac effects (palpitations, BP changes) and hypersensitivity reactions Major Side Effects Of AMINOGLYCOSIDE \| Pediatric nurse practitioner, Pharmacology nursing, Nursing mnemonics - [Nursing considerations:] monitor baseline renal labs, keep patient hydrated, monitor closely for hearing loss or decreased urine output, **may need to dose reduce in those with renal disease or poor kidney function** **Carbapenems** (ex. ertapenem) - Bactericidal, **very broad spectrum** (gram +, gram - & anaerobe coverage) - [Indications for use:] treatment of serious intra-abdominal, urinary tract, skin, bone & gynecological infections (see coverage chart for specific organisms) - [Contraindications & cautions:] caution with seizure disorders (can precipitate seizures), inflammatory bowel disorders (can cause pseudomembranous colitis), pre-existing renal disease - [Key adverse effects:] ***C. difficile* colitis/diarrhea** *(see image below of C. difficile colitis)*, significant GI effects (nausea/vomiting), **superinfections** (very common!), seizures can occur (typically pretty rare), nephrotoxicity  - [Nursing considerations:] monitor baseline renal labs, keep patient hydrated (important for kidneys as well as due to significant fluid losses if N/V an issue), watch for superinfections, narrow drug spectrum as soon as you can! **Cephalosporins** (ex. cefazolin \[1^st^ generation\]) Cephalosporin Antibiotic Drug Coverage by Generation Made Easy --- EZmed - There are 5 generations of cephalosporins, each differing in what organisms they cover - *Easiest way to remember*... the earlier generations have excellent gram + coverage (poor gram - coverage) and as you move towards the later generations the gram - coverage improves and the gram + coverage worsens - Exception would be the 5^th^ generation drugs that are excellent for MRSA coverage - Can be bactericidal and bacteriostatic (depends on dose used & specific drug), **spectrum varies** **based on drug (which generation)** - [Indications for use:] treatment of a wide variety of infections (see coverage chart for specific organisms) of varying severity... typically earlier generation drugs are used for milder infections & later generation drugs are used for more serious infections - [Contraindications & cautions:] known allergy (or allergy to penicillins), caution with hepatic or renal impairment, using concurrently with aminoglycosides (increases risk for nephrotoxicity), use for appropriate situations given significant rise in resistant bacteria - [Key adverse effects:] GI effects (N/V, diarrhea, anorexia), pseudomembranous colitis (later generation drugs), nephrotoxicity, **superinfections with broader spectrum drugs** - [Nursing considerations:] monitor baseline renal labs, keep patient hydrated (important for kidneys as well as due to significant fluid losses if N/V an issue), watch for superinfections, **teach patients to avoid any alcohol while taking these antibiotics (can cause disulfiram reaction)**, narrow drug spectrum as soon as you can! **Fluoroquinolones** (ex. ciprofloxacin) - Can be bactericidal and bacteriostatic (depends on dose used & specific drug), **very broad spectrum** (gram +, gram -, anaerobe & atypical coverage) - [Indications for use:] treatment of moderate to serious urinary tract, respiratory tract, and skin infections (see coverage chart for specific organisms) - [Contraindications & cautions:] caution with pre-existing renal or hepatic dysfunction, seizure disorders (can interfere with cell membrane channels), inflammatory bowel disorders (pseudomembranous colitis), **avoid use in children** **(\ - [Nursing considerations:] watch closely when giving drug (signs of anaphylaxis), teach patient to report rash or difficulty breathing if taking at home, usually pretty well-tolerated, lots of resistance has developed to these medications, **often given with clavulanic acid or sulbactam** (i.e. Augmentin, Unasyn) **in order to protect penicillin from bacterial beta lactamases** (used to combat resistance) **Sulfonamides** (ex. sulfamethoxazole) - Bacteriostatic, **broad spectrum** (gram + & gram - coverage) - [Indications for use:] **treatment of urinary tract infections** and STIs (see coverage chart for specific organisms), not being used as much for other infections due to increasing bacterial resistance - [Contraindications & cautions:] caution with renal disease or history of kidney stones, caution in elderly (increased CNS effects) - [Key adverse effects:] GI effects (N/V, diarrhea, abdominal pain, anorexia), renal effects (hematuria, proteinuria, kidney stones), CNS effects (dizziness, vertigo, ataxia), bone marrow suppression, Stevens-Johnson syndrome *(see pictures below)*  emDOCs.net -- Emergency Medicine EducationStevens-Johnson Syndrome and Toxic Epidermal Necrolysis in Pediatric Population - emDOCs.net - Emergency Medicine Education - [Nursing considerations:] monitor urine output & renal function, discontinue therapy immediately if hypersensitivity reaction (Stevens-Johnson syndrome) occurs, **encourage hydration to protect kidneys**, **often paired with trimethoprim (i.e. Bactrim) with each drug interfering with a different step in the folic acid synthesis pathway** (helps to combat resistance) **Tetracyclines** (ex. tetracycline) - Bacteriostatic, **broad spectrum** (gram +, gram - & atypical coverage) - [Indications for use:] treatment of mild to moderate respiratory tract, urinary tract, and STIs, as well as acne (see coverage charge for specific organisms), good alternative when penicillins are contraindicated - [Contraindications & cautions:] **avoid use in children \< 8 years of age (impact on developing teeth)**, caution with hepatic & renal dysfunction - [Key adverse effects:] GI effects (N/V, diarrhea, abdominal pain), **damage to teeth & bones in children (impacts mineralization & calcification causing staining & pitting, *see image below*)**, photosensitivity, superinfections, bone marrow suppression & hemolytic anemia (rare), hypersensitivity reactions  - [Nursing considerations:] teach patients about photosensitivity (wear sunscreen, avoid direct sunlight/tanning), monitor liver/renal function in patients with pre-existing insufficiency, watch for hypersensitivity reactions and superinfections **Lincosamides** (ex. clindamycin) - Primarily bacteriostatic (can be bactericidal at high doses), **broad spectrum** (gram +, MRSA & anaerobe coverage) - [Indications for use:] treatment of moderate to severe infections when less toxic antibiotics cannot be used, typically used for septicemia, skin/bone/joint infections, and severe acne, **often used for MRSA infections** *(see image below)* r/MedicalGore - The aftermath of a midnight trip to the ER for a MRSA infection resulting in emergent surgery. - [Contraindications & cautions:] use with caution in those with hepatic or renal impairment - [Key adverse effects:] **severe GI effects (**significant N/V**, pseudomembranous colitis \[often *C. difficile*\]), superinfections**, bone marrow suppression - [Nursing considerations:] monitor for GI effects & provide supportive care (hydration, small frequent meals), **discontinue use if *C. diff* colitis occurs (can be life-threatening), monitor for other superinfections (often skin-related, GI, or vaginal)**, watch for clinical signs of bone marrow suppression **Lipoglycopeptides** (ex. vancomycin) - Bactericidal, **broad spectrum** (gram + coverage, including MRSA) - [Indications for use:] **treatment of complicated skin & skin structure infections, including MRSA, as well as *C. difficile* diarrhea (PO vancomycin)** - [Contraindications & cautions:] **caution in those with pre-existing renal dysfunction**, use appropriately & only when necessary (when other drugs will not treat the causative organism) - [Key adverse effects:] GI effects (N/V, diarrhea, taste alterations, anorexia), **nephrotoxicity**, prolonged QT interval, Redman syndrome (see image below)  - [Nursing considerations:] administer slowly & watch for development of Redman syndrome, **follow vancomycin drug levels (trough) to titrate dosing, dosing adjustments often needed with renal dysfunction**, monitor urine output & renal labs to catch renal toxicity early **Macrolides** (ex. erythromycin, azithromycin) - Can be bactericidal or bacteriostatic (depends on species of bacteria & concentration of drug), **broad spectrum** (gram +, some gram - & atypical coverage) - [Indications for use:] treatment of **acute infections of upper respiratory tract**, urinary tract, skin, soft tissue, *H.pylori* & STIs, good alternative to those with penicillin allergy, good choice for very young, unvaccinated children to treat more severe URIs - [Contraindications & cautions:] caution in those with renal or hepatic dysfunction, caution in those with cardiac conduction defects - [Key adverse effects:] GI effects (N/V, cramping), **prolonged QT interval**, risk of pseudomembranous colitis, CNS effects (confusion), superinfections, hypersensitivity reactions Prolonged QT interval - Mayo Clinic - [Nursing considerations:] **relatively well-tolerated compared to some of other antibiotic classes**, monitor for superinfections/*C. difficile* colitis, monitor for CNS effects (concern for safety) **Antiseptics** (ex. nitrofurantoin) - Can be bactericidal or bacteriostatic (depends on concentration of drug), **broad spectrum** (some gram +, gram - coverage \[though many gram - species & Pseudomonas species are resistant\]) - [Indications for use:] **treatment of lower urinary tract infections** (therapeutic effects in [urine only]), can be used for recurrent UTIs - [Contraindications & cautions:] known allergy, use with caution in those with penicillin or cephalosporin allergy (possibility of cross-reactivity, though data inconclusive thus far), caution in those with renal or hepatic dysfunction - [Key adverse effects:] GI effects (N/V, diarrhea), hepatic toxicity (elevated liver enzymes), pulmonary reactions (dyspnea, chest pain, chills, cough), bone marrow suppression, hemolytic anemia, peripheral neuropathy (extremity numbness/tingling) - [Nursing considerations:] monitor hepatic function & CBCs over time, watch for pulmonary reactions, usually not 1^st^ line therapy for UTIs given side effects profile! **Anti-mycobacterial (anti-TB drugs)** (ex. rifampin, rifapentine) - Can be bactericidal or bacteriostatic (depends on species of bacteria & concentration of drug), **broad spectrum** (gram + \[including MRSA\], gram - & *Mycobacterium tuberculosis* coverage) - 1^st^ line drugs are used in combinations of 2 or more agents until improvement is seen - Fluoroquinolones have also found to effective as 2^nd^ line agents to treat TB - [Indications for use:] **used to treat TB (typically as combination therapy)**, treatment must be continued for 6 months up to 2 years (in order to affect bacteria at various phases during their long & slow life cycle) - [Contraindications & cautions:] caution in those with pre-existing hepatic or renal disease, seizure disorders or pre-existing neuropathies - [Key adverse effects:] GI effects (N/V), **discoloration of body fluids**, peripheral neuropathies (numbness/tingling of hands & feet), bone marrow suppression - [Nursing considerations:] monitor baseline & periodic liver & renal function tests, ensure patient receives full course to prevent development of resistant strains, monitor for CNS changes, teach patients about discoloration of body fluids (so they aren't surprised by it, *see image below*)