MRSA Study Guide

837 Study Guide CA-MRSA TX: DM Clinda to see her Back Line - ALL are Oral Doxycycline (Vibramycin) Minocycline Clindamycin Bactrim Linezolid (Zyvox) MRSA: “Very Determined To Cure Zyvox” Vancomycin Daptomycin Tigecycline Ceftaroline - 5th Gen, only one for MRSA Zyvox (IV/PO) No Renal Adjustment: NOC-MDMT-LA N - Naficillin O - Oxicillin C - Ceftriaxone M - Moxifloxacin D - Doxycycline M - Minocycline T - Tigecycline L - Linezolid A - Azithromycin Q24H: “Ex Credit Allowed once Today” - Ertapenem (Invanz) - Ceftriaxone (Rocephin) - Aminoglycosides - Telavancin UTIs ● ● Uncomplicated ○ “For Best Management” ○ Fosfomycin ○ Bactrim ○ Macrobid CoMpLiCaTeD ○ AmInOgLyCoSiDeS ■ Plazomicin (Zemdri) QTc Prolongation: (Normal ~450) QT Feels MACRO Today - FQ (Moxi> Levo>Cipro) MLC - Macrolides - Telavancin *Note: low K or Mg increases the risk Hepatic Dose Adjustment - Metronidazole Do NOT Refrig (Oral Susp. & IV): - Cefdinir (Omnicef) OS - Only B-Lactam to not ref. - Azithromycin - Clarithromycin (Biaxin) - Clindamycin (Cleocin) - Metronidazole (Flagyl) - IV - Fluoroquinolones - Cipro, Levaquin, Avelox - Bactrim No CNS Penetration (DOC: Ceftriaxone) - Cefazolin - Zosyn More Common Antibiotic Allergies - Cefaclor, Cephalexin, Cefadroxil - If Penicillin allergy - Aztreonam if allergy to Ceftazidime Decreases INR w/ Warfarin: - Rifampin (inducer) Increase INR w/ Warfarin: “BCFFF” - Bactrim - Clarithromycin - FQ - Fluconazole - Flagyl Take With Food: 837 Study Guide MACROBurgers at the METRO w/ DOXY - Macrobid - Metronidazole (Flagyl) - Doxycycline (Vibramycin) Urine Discoloration: - Flagyl - Macrobid - Rifampin IV Dilution: - Saline Only: - Ampicillin - Unasyn - Daptomycin - Ertapenem - Caspofungin - Dextrose Only: - Bactrim - Synercid - AmphoB Protect from Light: Light LINEs & VIBes at the BACk of the METRO - Linezolid - Doxycycline (Vibramycin) - Metronidazole - Bactrim (Sulfa) Concentration Dependent Killing: - Aminoglycosides - Daptomycin - Bactrim Atypical (L/M/C) Coverage: - Fluoroquinolones - Tetracyclines - Macrolides 837 Study Guide Inhibitors of Protein Synthesis (Kassan) & Clinical Pharmacology 2 (Lee) Target 30S: “A.T. 30” - Aminoglycoside: - Irreversible, bactericidal - CONCENTRATION dependent killing - “GNATS” G(-) coverage only (PSA coverage) - Lots of polar bonds (amino & hydroxyl groups) hydrogen bond with the 30S - MOA: ribosomal misreading & block 30S movement - protein mutation → membrane alteration (allow more AB into cell) - Low concentration → makes fake proteins 837 Study Guide - - - - Inhibit protein synthesis - High concentration → ribosome inhibition leading to cell death Resistance Mechanism: - Modifying enzymes - Inactivate aminoglycosides - Acetylation, phosphorylation, adenylation - Reduce drug uptake - Efflux pump & porin structural changes - Upregulation of membrane protease - Scans cytosol & breaks down faulty proteins - 30S mutations (drug unable to bind) - inhibit binding site Synergistic effect when combined with cell wall disrupters (Blactams & Vanco) - DO NOT mix in SAME syringe as B-Lactams! →inactive complex forms ADRs: - Nephro (reversible) & Ototoxicity (irreversible) - Avoid in pregnancy - High Peaks, low troughs targeted - dosed Q24H - Gentamycin/Tobramycin <1 mcg/mL before next dose - Neuromuscular blockade - Give Calcium Gluconate - C/I: myasthenia gravis Tetracyclines: “DMTT” - Covers what Aminoglycosides don’t - 4 linearly fused 6-member rings - Lots of polar bonds bind with RNA - Reversible, bacteriostatic - MOA: Blocks ribosome movement → inhibits AA synthesis - Resistance Mechanisms: - - Ribosomal protection proteins prevent binding Impaired penetration - Efflux pumps - Porin modification - Enzymatic inactivation Newer Tetracyclines: Amino group addition helps overcome resistance ADRs: - Chelation: Permanent teeth discoloration - C/I <8years & pregnancy - GOOD for tooth infections! - penetrates well - Chelate with cations - TAKE ON AN EMPTY STOMACH - EXCEPT Doxycycline - take with food! - Esophageal ulcers (stay upright for 30 min) - CNS (dizziness), Kidney & Liver Damage, Photosensitivity 837 Study Guide - Tigecycline BBW: high mortality rate Clinical: Good for respiratory infections & MRSA - L/M/C coverage - Lyme’s Disease DOC - Doxy & Mino - HIGH BA, no renal adjustment needed - P450 INHIBITOR - Tigecycline: covers everything but PPP Target 50S: “ML SO PC 50” - Macrolides: - “-thro- the Macro to CLOG.” - Bacteriostatic: TIME-DEPENDENT activity - Large macrocyclic lactone ring - Unstable in stomach acids - coated tablets - MOA: Bind to 50S, inhibit ribosome movement, stop peptide elongation - ADRs: “CLOG” - CV (QTc prolongation), Liver, Oto-, GI (Erythromycin causes diarrhea) - DDI: DO NOT give with Chloramphenicol - Bind to the same 50S region, compete & neither reach therapeutic effects - Resistance Mechanisms: - Binding site modification, increased efflux, enzyme modification (breaks down the Macrolide) - - - Fidaxomicin (Dificid PO) - BacteriCIDAL for C.Diff infection - Minimal BA (stays in the gut) - MOA: Inhibit RNA polymerase - Similar macrolide structure, different MOA Macrolide Clinical: - Spectrum: - Covers everything respiratory (good lung penetration) - Strep pneumoniae, H. influenzae, MCat - Atypical (LMC) Coverage - MAC Coverage - DDI: Clarithromycin >> Azithromycin - Azithromycin NO RENAL adjustment needed Lincosamides: - Clindamycin causes C.Diff SUPERinfection - MOA: Work on 50S, stop ribosome movement, prevent AA elongation - Similar to Macrolides 837 Study Guide - SHOULD NOT BE COMBINED WITH MACROLIDES OR CHLORAMPHENICOL - Same binding sites Clinical: - Spectrum: G(+) & anaerobes - NOT recommended in IAI - Anti-toxin effect! - D-test must be negative to use Cleocin! - Streptogramins: - A mixture of 2 components that must be coadministered to work - Synergistic: 100x more active than separate components - MOA: Both bind to 50S & prevent AA elongation - Water soluble: IV - Oxazolidinones: - Linezolid (Zyvox) - “3 things in the Line to be aware of” - 600mg IV/PO Q12H - PO nearly 100% BA - MOA: prevent 70S formation (the larger complex) - Translation cannot even start - ADRs: - Myelosuppression (thrombocytopenia) → monitor CBC weekly - >2 weeks – NOT good for long-term use! - Mitochondrial toxicities with prolonged tx - DDI: - MOA-A: - - - Serotonin Syndrome Tyramine Toxicity (HTN crisis) - Unaffected by CYP450 Clinical: - Spectrum: - Covers everything G(+) - same as Dapto - VRE, VSE, MRSA, VRSA - Bacteriostatic to these - Bactericidal to streptococci - Indications: VRE, CAP & HAP (pneumoniae) Metronidazole - 9 part story - Flag down the Metro train at the station (Flagyl) - Only has one stop (ONLY covers B. Frag) - While I was waiting, my stomach hurt (DOC for IAI & Alternative for C. Diff) - No refrigerator was there (Do NOT refrigerate IV) - But I want to eat (Take with food) 837 Study Guide - Metal everywhere (Metallic Taste) It makes me thirsty for water, not alcohol (Do NOT drink Alcohol x3 days Disulfiram Rxn) It was dark, and I had to pee (Darkened Urine) I saw a murder, so I left (BacteriCIDAL) Nitrofurantoin (MacroBID) - MOA: inhibit protein synthesis - For uUTI - NOT effective in kidney infection - High urine concentration is required for antibiotic effects - Darkens urine - Monitor: KIDNEYS! - - C/I: CrCl <60 Pleuromutilins: MOA: inhibit the start of translation - Retapamulin: introduction of the thioether Chloramphenicol: MOA similar to Macrolides & Lincosamides (Clindamycin) - ADRs: Bone marrow suppression (aplastic anemia) & “Gray Baby” Syndrome Antimicrobial PD (Lee) Cmax/MIC Ratio: Aminoglycosides - HIGH peaks: helps concentration-dependent killing - concentration over MIC is vital for bactericidal effects - low troughs: reduces nephrotoxicity - gives a washout period - Dosing strategy: use the highest possible dose w/o toxicity - Target: 10x MIC AUC/MIC: Fluoroquinolones, Aminoglycosides & Vanco - NEW Vanco TDM Target: AUC 400-600 - Above 400: increases efficacy - Below 600 avoids nephrotoxicity - Serious MRSA infections: Initial Dose: Vanco 15-20mg/kg (ABW) Q8-12H - Infusion Time: MAX 1 gram/ hour - Adjust for renal fxn T>MIC: B-Lactams - Time-dependent: MAXimize time above MIC - vital for killing bacteria - Higher dose - More frequent dose - Increase the duration of infusion (extended infusion) 837 Study Guide - - ***Continuous infusion optimizes time above MIC*** When MIC is low, the time of infusion doesn’t matter as much - Any dosing regimen works just as good - Extended infusion is preferred when the MIC is high Appropriate Use of Anti-Infective Agents (Lee) Systemic Approach to Selecting an Antimicrobial: - Is there an infection? - What’s causing it? - Which empiric tx covers this pathogen in the location of infection? - How do we monitor the efficacy? How do we know if the patient has an infectious disease? - Fever: single 101’F measurement or more than 100.4’F over 1 hour - WBC: elevated, increased left shift band ≥10% - Prolactin levels: elevated = bacterial infections in pneumonia, sepsis & CNS - Monitor: CRP & ESR Empiric Drug Selection: - Susceptibility testing in last 12 months - AB use in the past 30 days - Recent hospitalization or IV antibiotics in 90 days (more resistant) - Host Factors: allergies, age, immune & organ fxn, pregnancy, chronic diseases - Seizures: AVOID Imipenem/Cilastatin - Cystic Fibrosis or COPD: suspect resistant pathogens Penicillin Allergy & Cross-Reactivity: Do NOT challenge a pt w/ documented IgE mediated rxn (anaphylaxis) or laryngospasm - AVOID ALL B-LACTAMS except Aztreonam FOR SAFETY - Cephalosporins: 2% - Amino-cephalosporins more likely (same side chain) - Cefaclor, Cephalexin, Cefadroxil - Carbapenems: 1% - Monobactams: 0% - But if pt is allergic to Ceftazidime, do NOT give Aztreonam (same side chain) Important DDIs: - FQ: chelation & hepatic enzyme interactions - Tetracyclines: chelation - Carbapenems: decrease Valproate absorption (^ chance of seizures) - Macrolides: Clarithromycin (X), Azithromycin (C): increase Simvastatin & Atorvastatin - Increase INR w/ Warfarin: Clarithromycin, FQ, Fluconazole, Bactrim, Flagyl - Rifampin: Enzyme inducer (decrease INR w/ Warfarin) 837 Study Guide Toxicities: - Nephrotoxicity: - Aminoglycosides - Vancomycin - Polymixins (Colistin) - Zosyn - AmpB - Ototoxicity: - Aminoglycosides - Vanco - Azithromycin - Seizures: - Imipenem/Cilastatin - Cefepime - B-lactams - Neurotoxicity: - - - Polymixins - Isoniazid - FQ - Minocycline Hematologic: - Chloramphenicol - B-lactams (Nafcillin) - TMP - Linezolid - Vancomycin Photosensitivity: - FQ - Sulfa - Tetracyclines - Macrolides Always consider the cost (PO is cheaper than IV) & compliance (daily is better than BID+) No response in 2-3 days? → REEVALUATE - Consider host factors (immune fxn) - Stage 4 cancer? → immune system doesn’t work Bacterial Resistance (Lee) Gram(+): - - C. Diff: - Vanco PO - Dificid (Fidaxomicin) PO Staphylococcus Aureus: - Staph Aureus Risk Factors: - Hospitalization within 90 days - IV Antibiotics with 90 days - Exposure to pt with infection or colonization of MRSA - Treatment Options: - Very - Vanco IV - Dedicated - Dapto (Cubicin) IV - To - Tigecycline (Tygacil) IV - Cure - Ceftriaxone (Teflaro) IV - Zyvox - (Linezolid) PO/IV - VSSA (Vanco Susceptible) - For MIC = 2mg/L → use alternative agent - MRSA: resistance is mainly due to PBP alternation 837 Study Guide - CA-MRSA: - PO - - - - DM - Doxycycline (Vibramycin) / Minocycline (Minocin) Clinda - Clindamycin (Cleocin) Bac - Bactrim or Septra Line - Linezolid IV: - Very - Dedicated - To - Cure - Zyvox Problems with MRSA agents: - Vanco - slow killing, narrow TI (AUC/MIC=400-600; nephrotoxicity) - Linezolid - bacterioSTATIC, DDIs (SS), ADRs (Thrombocytopenia monitor CBC for platelets) - Daptomycin - NOT indicated for pneumonia - Tigecycline - BBW: ^ mortality, not for bacterimia (deep tissue penetration), high GI toxicity - Ceftaroline - Data limited to MRSA ABSSSI, neutopenia associated with long-term use Enterococcus spp - Clindamycin & Cephalosporins: NO Enterococcal coverage - VSE (E. Faecalis): - DOC: Ampicillin - Choose B-lactams over Vanco - VRE - ⅓ of all Enterococci - IAI - rarely community-acquire (part of normal flora) - DOC: Linezolid or Daptomycin Streptococcus Pneumoniae - Treatment: - FQ: Levfloxicin & Moxifloxicin - Warning: many BBW & high collateral damage - Cephalosporins: - 3rd Gen: - Ceftizadine (Fortaz) - Ceftriaxone (Rocephin) - Cefdinir (Omnicef) PO - Cefotaxime - 4th Gen: - Cefepime (Maxipime) 837 Study Guide - Beta-Lactamases: Mechanisms for Enzyme Resistance - Class B: Metallo-B-Lactamase - Hydrolyze carbapenems, penicillins, and cephalosporins - Resistance to these - NOT Aztreonam (we use this for treatment) - Class C: Overproduction of AmpC - 3rd gen cephalosporins & cephamycins - Resistance to these Gram(-): - - - - - - Extended Spectrum Beta-Lactamases (ESBL) - Mainly expressed in Klebsiella, E. Coli, Proteus Spp (Enterobacterales-top right) - DOC: Carbapenems - benefit, dosed q24h - Ertepenem (Invanz) - Merpenem (Merem) - Imipenem/Cilastatin (Primaxin) AmpC-Enterobacterals - DOC: Cefepime (Maxipime - 4th gen) & Carbapenems - Ceftiraxone (Recephin) is susceptible but we do NOT use it! CRE: Carbapenem-Resistant Enterobacterales - Genes: - KPC: Avycaz (Ceftazidime/Avibactam) - reversible - MBL: Avycaz + Aztreonam (Azactam) - OXA-48: Avycaz Avycaz - Limited to G(+) activity - Active against MDR gram(-) bacilli Cefiderocol (Fetroja) - new cephalosporins - “Trojan” strong antibiotic uses bacterial iron transport system to enter periplasmic space - Active against - Enterobacterales (Class A, B, C, D) - MDR-PSA - Carbapenenem resistant Acinetobacter P. Aeruginosa (PSA) - Treatment: - Beta-lactam - Penicillins: - Zosyn - Cephalosporins: 837 Study Guide - - - Ceftazidime (Fortaz) - Cefepime (Maxipime) Monobactam: - Aztreonam (Azactam) Carbapenems: - Imipenem/Cilastatin (Primaxin) - Meropenem (Merrem) - Doripenem PSA Tx When Beta-Penicillins are NOT tolerable: - Aminoglycoside - Amikacin - Plazomicin>Tobramycin>Gentamicin - FQ: - Ciprofloxacin, Levofloxacin - Polymyxins: (Nephrotoxicity, Neurotoxicity) - Polymyxin B - Colistin = Polymyxin E - DTR-PSA or “MDR PSA”: Difficult to Treat Resistance Pseudomonas - DOC: Zerbaxa (Ceftolozane/Tazobactam) - Alternates: Azvycaz….*ASK Lee* - CRAB (Carbpenem Resistant Acinetobacter) - Preferred: Sulbactam/Durlobactam (Xacduro) PLUS a Carbapenem (imipenem or meropenem) - Used for - Alternative: High-dose Unsyn (Ampicillin/Sulbactam) - The active ingredient to treat CRAB is the B-Lactamase Inhibitor!! Stenotrophomonas maltophilia - Use combo therapy: TMP/SMX (Bactrim, Septra) - Sepsis & Septic Shock (Salvatus) Sepsis: life-threatening organ dysfunction caused by a response to infection SOFA: Sequential Organ Failure Assessment qSOFA: (quick) - RR ≥ 22 - SBP ≤ 100 - ALTERED MENTATION 837 Study Guide SIRs: Systemic Inflammatory Response Syndrome - Sepsis → ≥2 criteria + infection - Hypo/Hyper Thermia: Temp > 100.4 F or <96.8 F - ^ HR (>90 bpm) - ^ RR (>20) or PaCO2 < 32 - WBC >12 or <4 or >10% bands Sepsis → ↓Blood Volume → ↓Tissue O2 → ↓Organ Fxn (failure) Organs involved: heart, liver, spleen, lung , kidneys Shock: state of hypoxia Septic Shock: distributive shock – lack of blood distribution to capillaries to provide organs with blood (& O2) - Serum lactate > 2 AND vasopressors needed to maintain MAP≥65 - Despite adequate fluids Sepsis Bundle: Measure lactate level (remeasure if >2) - Normal lactate: 0.5-1.5 mmol/L 2. Blood culture BEFORE a.b. (≥2 sets) 1. 3. Broad-spectrum a.b. 4. Crystalloids for hypotension or lactate ≥4 - 30 mL/kg minimum (rapid admin) - IBW - Balanced crystalloids preferred (Lactated Ringer, Plasma-Lyte) Start ^ these steps in the FIRST hour GOAL: improve tissue perfusion Target: MAP≥65; if not add ↓ 5. Apply VASSOPRESSORS - Levophed (Norepinephrine): 1st-line single agent - Mix w/ D5W or NS - Phenylephrine is good for pt w/ arrhythmias Adjunct Therapy: - Glucocorticoids - No mortality benefit, used if there’s an ongoing need for vasopressors - VTE Prophylaxis - UFH: 5000 units SQ q8-12h - LMWH (Enoxaparin) Lovenox PREFERRED - 40 mg SQ daily - CrCl <30: 30 mg SQ daily (or use heparin) Stress Ulcers PPX: 837 Study Guide - - - - PPI (preferred) - H2RA: Famotidine (renally adjust prn) Glucose Control - Target level: <180 - Initiate insulin if glucose ≥180 - Monitor q1-2h until stable - Goal: avoid hypo/hyperglycemia Additional: - Blood infusion, nutrition, neuromuscular blockers (for mechanical ventilation), antipyretics - Assess & follow-up after discharge: physical, cognitive, and emotional problems Response: - Resolution of Sepsis (response to fluids) may take hours to days - De-escalation & duration of Antibiotics - Narrow after cx results and/or s/sx improvement - Longer courses (7-10d) in pt w/ slow clinical response URTI (Van) Acute Otitis Media (AOM): (1 of 3 subtypes w/ the greatest A.B. role) - Presentation: - Inflammation of the middle ear - PAIN is the differentiating symptom - Follows viral URTI, children more susceptible - Bacteria: - Strep. Pneuomoniae - H. influenzae - M. cat - Diagnosis: - Middle Ear Effusion - Ear discharge - Red & bulging tympanic membrane - Ear pain within 48 hrs - Fever, severe if ≥102.2F - ABX Indication - 6 months- 12 yrs bi/unilateral & severe s/sx → give AB tx - 6mo-2y bilateral ear infection → give AB tx - 6mo-2y unilateral ear infection→ AB tx or observe - 2-12y w/o s/sx→ AB tx or observe - Treatment: (for Pain & Infection) - Pediatric: 837 Study Guide - - 1st Line: Amoxil 45mg/kg BID - If AB in past month, hx of dx, eye infection w/ discharge - Augmentin (same dose) - Penicillin Allergy: - Omnicef (Cefdinir) - Ceftin (Cefuroxime) - Vantin (Cefpodoxime) - Rocephin (Ceftriaxone) - Tx Fail after 2-3 d: - Augmentin - Rocephin - Alternates: Cleocin - Adjunct: pain & fever management (Tylenol & IBU) - Duration: - ≤2 y or severe sx → 10 days - Severe sx: pain (48h) & fever ≥102.2F - 2-5 y → 7 days - ≥6 y → 5-7 days Prevention: Pneumococcal & Flu Vaccines Complications: - Mastoiditis - Bacteremia - Meningitis - Speech & language impairment Acute Bacterial Rhinosinusitis: - Presentation: - inflammation/infection of paranasal sinuses - Bacteria: - S. pneumoniae - H. influenzae - Persistant s/sx ≥ 10d - Severe s/sx 3-4d - Worsening after viral infection “double sickening” - Nasal discharge/congestion - Facial pain - Fever - Diagnosis: - Gold standard: sinus puncture (invasive costly, painful) - Treatment: - Children: - 1st Line: Augmentin 22.5mg/kg BID - 2nd Line: Augmentin 45 mg/kg BID 837 Study Guide - - Alternative (Failed tx or Penicillin allergy): Cleocin + Cefixime or Cefpodoxime - Non-type 1 allergy - Levaquin for type 1 allergy Severe Infection (Hospitalization): IV Unasyn, Rocephin, cefotaxime or Levaquin - Adult: - 1st Line: Augmentin 500mg TID or 875mg BID - 2nd Line: Augmentin 2,000 mg BID - Risk for Resistance or Failed Tx: Augmentin 2,000mg BID - High-Dose Augmentin: - Regions w/ ≥10% invasive S. pneumoniae - Severe Infection (Fever 102.2F or 39c) - Daycare - < 2 or >65 years - Hospitalized in past 5 days - Antibiotic use in past month - Immunocompromised Duration: - Uncomplicated: 5-7 days - Risk for Resistance: 7-10 days - Children: 10-14 days Adjunct: saline irrigation, intranasal corticosteroids (hx of rhinitis), Referral: - Sx worsen after 2-3 days despite AB use → change tx - Sx persist/worsen 72 hrs after use of second line→Referral - - Acute Pharyngitis: - Presentation: - oropharynx/nasopharynx infection - Swollen uvula, whitish spots on tonsils, gray furry tongue - Sore throat, Pain swallowing - Enlarged lymph nodes - Scarlatiniform rash - Bacteria: GAS (Group A Strep = Strep Throat) - Diagnosis: - RADT - Gold Standard: Throat Swab Culture (24-48 h) - Not routinely recommended - Who not to Test for GAS: - NOT for children <3 years or if s/sx are viral (cough, oral ulcers) - Unless a sibling has GAS - Treatment: 837 Study Guide - - - - 1st Line: - Penicillin V→10 days - Penicillin G→ 1 dose - Amoxicillin (Amoxil) → 10 day Penicillin Allergy - Keflex (Cephalexin) → 10 days - Duricef (Cefadroxil) → 10 days - Cleocin (Clindamycin) → 10 days - Biaxin (Clarithromycin) → 10 days - Azithromycin (Zithromax) → 5 days - 500 mg 1 day then 250 mg for 4 days Adjunct - Acetaminophen or NSAIDs (Fever) Complications: - Acute rheumatic fever - Fever & affects multiple organ systems - CV, Musculoskeletal, Skin, CNS (Chorea) Skin & Soft Tissue Infections (Lee) Classification of SSTI’s ● Simple Uncomplicated g(+) ○ Boils folliculitis, furuncles, carbuncles (Purulent) ○ Impetigo ○ Cellulitis ○ Erysipelas (Non-Purulent) ● Complicated g(+), g(-), anaerobes ○ Diabetic foot infection (Non-Purulent) ○ Necrotizing fasciitis (Non-Purulent) ○ Celulitis ○ Gangrene ● Purulent ○ Staphylococcus aureus (MSSA + MRSA) ● Nonpurulent ○ GAS (S. Pyogenes) ○ MSSA + MRSA Severity of Purulent vs Non-purulent ● Mild ○ Local Infection ● Moderate ○ Systemic signs- Fever + leukocytosis ● Severe ○ Failed incision + oral antibiotics 837 Study Guide ○ ○ Immunocompromised SIRS (=Sepsis) ■ Sepsis- Dysregulated response organ failure due to infection ■ SIRS (Must meet 2 criteria) ● Temperature- >38C (100.4 F) or <36C (96.8 F) ● HR- > 90 beats/min ● RR- >20 breaths/min ● WBC- > 12,000 or < 4,000 or 10% bands Purulent “BDBDC” ● Mild ○ Warm heat promote drainage ● Moderate ○ TX: Incision + Drainage, C/S, PO meds ○ Empiric: Bactrim or Doxycycline (minocycline) 5-10 days ○ Definitive: ■ MRSA: Bactrim ■ MSSA: Dicloxacillin or Cephalexin ● Severe (Sepsis) ○ Tx: Incision + Drainage, C/S, IV meds ○ Empiric Tx: Vancomycin, Daptomycin, Linezolid, Telavancin, or Ceftaroline ○ Definitive Tx: ■ MRSA: Empiric ■ MSSA: Nafacillin, Cefazolin or Clindamycin CA-MRSA “DM Clinda Bactrim Line” ● Empiric PO antimicrobial therapy ○ Doxycycline ○ Minocycline ○ Clindamycin ○ Bactrim ○ Linezolid ● Severe MRSA IV therapy ○ Vancomycin ○ Linezolid ○ Daptomycin ○ Tigecycline Impetigo ● GAS (S.Pyogenes) ● S. aureus ○ Small, fluid vesicle, lesion dry to form golden yellow crusts commonly on hands and face of children ○ Transmittable 837 Study Guide ○ ○ TX: ■ Dicloxacillin ■ Cephalexin TX MRSA: ■ Doxycycline ■ Bactrim ■ Clindamycin Erysipelas ● GAS (S.Pyogenes) ○ Painful lesion with defined demarcated edges ○ TX: ■ Penicillin V PO or Penicillin G IV/IM Lymphangitis ● GAS (S.Pyogenes) ○ Inflammation involving the subcutaneous lymphatic channels ○ Secondary to puncture wounds, infected blisters or skin lesions ○ TX: ■ Penicillin G IV 1-2 million units Q 4-6 h for 2-3 days then followed by Penicillin VK PO for 10 days Cellulitis (Non-Purulent) ● S. aureus ● GAS (S.Pyogenes) ○ TX: ■ Mild PO ● Penicillin VK, Cephalexin, Dicloxacillin or Clidamycin ■ Moderate IV ● Nafacillin, Ceftriaxone, Cefazolin, Clindamycin ■ Severe IV ● Vancomycin + Zosyn OR meropenem OR imi/cilastatin Necrotizing Fascitis ● Severe ● Empiric TX: ○ (Vancomycin or Linezolid) +( Zosyn or Carbapenem) ● Definitive TX: ○ Monomicrobial ■ S. Pyogenes: Penicillin + Clindamycin (anti-toxic effects) ○ Polymicrobial ■ Vancomycin + Zosyn Acute Bacterial Skin and Skin structural Infections ● Ceftaroline ● Tedizolid ● Lipoglycopeptide IV ○ Dalbavancin T1/2 (1,000 mg day 1 & 500 mg day 8) 837 Study Guide ■ Lasts in the body for a whole week Decubitus Ulcer (Pressure Sores) ● Ulcer Infection can reach muscle or bone ● Occurs when someone is sitting down for too long (Larger obsessed people) Bite Wounds (Human, dog or cat) ● Animals: Pasteurella multocida ● Humans: Streptococcus, S. aureus, anaerobes, Eikenella ● TX: ○ Amoxicillin-Clavulanate (Augmentin) ○ Antimicrobial prophylaxis for 3-5 days: All human bite due to high infection risk or animal bite in immunocompromised pts or deeper wounds Lyme Disease ● Borrelia burgdorferi→ Infected blacklegged ticks ● Sx ○ Skin Rash= Erythema migrans= Bull's Eye ● Tx: ○ Doxycycline 100 mg PO BID x 10 days ■ ADR’s ● Photosensitivity ● Chelation- avoid milk + antacids ■ CI ● Children <8 ● Pregnancy ● Alternative TX: ○ Amoxicillin or Cefuroxime Bone Infections (Lee) Osteomyelitis ● Infection by 3 routes: ○ Hematogenous Spread (Blood infection) ○ Contiguous Source (Injury) ○ Vascular Insufficiency (Diabetic Foot Ulcer) ● S. aureus ● Diagnosis tool ○ MRI ○ CT ○ Identification of causative microorganism ● Duration of therapy ○ 4-8 weeks ● Success for eradication 837 Study Guide ● ○ Antibiotic and Surgical Therapy Approach to TX: ○ Bactericidal ○ High dose ○ IV ○ Long duration if therapy Epidemiology + Etiology of Hematogenous Osteomyelitis ● Risk Factor ○ Sickle Cell- Salmonella ○ ICU, hemodialysis - P. aeruginosa Vertebral Osteomyelitis ● S. aureus ● Diagnosis Tool ○ MRI ○ Blood Cultures ○ CT (biopsy) ● Duration of therapy ○ 6-8 weeks or longer ● If hardwear presents with early (1 month) post-op infection ○ Debridement + Long term antibiotic tx ● If hardwear presents with late post-op infection ○ Remove hardware + antimicrobial therapy ● Follow-Up ○ ESR ■ Erythrocyte Sedimentation Rate (Increases when infection) ○ CRP ■ C-Reactive Protein (Increases when Inflammation) DM or Vascular Insufficiency ● Foot commonly involved ● Probe to the bone test ● Management ○ Dead space ○ Adequate surgical drainage ● TX ○ Failure due to inadequate debridement ● Lab Test ○ ESR, CRP, WBC ○ Positive B/C in 50 % pts ● Antibiotic TX ○ MRSA ■ Vancomycin, Daptomycin, linezolid 837 Study Guide ○ ○ ○ ○ ○ ○ VSE ■ Ampicillin VRE ■ Linezolid, Daptomycin Enterobacteriales ■ Cefepime, Ertapenem ■ Penicillin allergy - Ciprofloxacin, Aztreonam Pseudomonas ■ Cefepime, meropenem Streptococcus ■ Penicillin G or Ceftriaxone Salmonella ■ Ciprofloxacin Empiric Antibiotic therapy of Osteomyelitis ● Newborn ○ Cefazolin ● Adult ○ Vancomycin IV or Cefazolin ● IVDA (IV Drug Abusers) S. aureus, p. Aeruginosa ○ Vancomycin IV + Ceftazidime, Cefepime, Ciprofloxacin Monitoring Protocols ● Culture and sensitivity ○ Initiation of tx ● WBC count ○ Weekly until normal range ● ● ● CRP ESR ○ Weekly Sign/Sx ○ Daily during initiation tx Compliance of out px ○ Reinforce before starting oral tx ○ Every office visit Candidate for Oral AB Therapy ● Confirmed osteomyelitis ● Initial positive response to IV antibiotics ● PO available ● Adherence ensured ○ Adults don't have DM or PVD ○ Infection sensitive to FQ Duration of Therapy 837 Study Guide ● ● ● ● ● ● 4-8 weeks Acute Osteomyelitis: 4-6 Weeks Septic Arthritis (Joints): 3-4 Weeks Vertebral Osteomyelitis: 6-8 weeks Children: 4 weeks Prosthetic Devices: 8 Weeks Prosthetic Joint Infection (PJI) ● Coagulase Negative Staphylococcus ● Removal of prosthetic ○ Duration tx: 6 Weeks of bactericidal tx ● Surgical drainage + prosthetic retention ○ Hip: 3 weeks ○ Knee: 6 week ● Antimicrobial Treatment of PJI ○ Rifampin ■ Tuberculosis ■ Added for infection with biofilm of prosthesis for better penetration (adjuct therapy) ■ ADR ● Hepatotoxicity ● Orange Discoloration of body fluids ■ Cyp450 inducer ● INR down (Only one)