Antibiotic classes
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This document provides an extensive review of various antibiotic classes, including beta-lactams, cephalosporins, fluoroquinolones, and macrolides, detailing their spectrum of activity, pharmacology, adverse effects, and historical context of antibiotic resistance. Key information covers the development of different penicillin variants to combat resistant bacteria and the timeline of resistance emergence. It includes detailed descriptions of the effectiveness and limitations of these antibiotics against specific bacteria, along with relevant safety considerations.
![S. aureus
Penicillin
[1950s]
Penicillin-resistant
S. aureus
Evolution of Drug Resistance in
S. aureus
Methicillin
[1970s]
Methicillin-
resistant
S. aureus (MRSA)
Vancomycin-resistant
enterococci (VRE)
Vancomycin
[1990s]
[1997]
Vancomycin
intermediate-
resistant
S. aureus
(VISA)
[ 2002 ]
Vancomycin-
resistant
S. aureus](https://image.slidesharecdn.com/antibioticclasseskhaledsaad2014-140803004558-phpapp01/85/Antibiotic-classes-57-320.jpg)
Antibiotic classes
- 1. A Review of Antibiotic Classes Khaled Saad Zaghloul 2014
- 2. Bacteria by Site of Infection Mouth Peptococcus Peptostreptococcus Actinomyces Skin/Soft Tissue S. aureus S. pyogenes S. epidermidis Pasteurella Bone and Joint S. aureus S. epidermidis Streptococci N. gonorrhoeae Gram-negative rods Abdomen E. coli, Proteus Klebsiella Enterococcus Bacteroides sp. Urinary Tract E. coli, Proteus Klebsiella Enterococcus Staph saprophyticus Upper Respiratory S. pneumoniae H. influenzae M. catarrhalis S. pyogenes Lower Respiratory Community S. pneumoniae H. influenzae K. pneumoniae Legionella pneumophila Mycoplasma, Chlamydia Lower Respiratory Hospital K. pneumoniae P. aeruginosa Enterobacter sp. Serratia sp. S. aureus Meningitis S. pneumoniae N. meningitidis H. influenza Group B Strep E. coli Listeria
- 4. Discovery of penicillin Alexander Fleming 1928 Nobel Prize, 1945
- 5. β-Lactam Characteristics Same mechanism: Inhibit cell wall synthesis Bactericidal (except against Enterococcus sp.) Short elimination half-life Primarily renally eliminated (except nafcillin, oxacillin, ceftriaxone, cefoperazone) Cross-allergenicity - except aztreonam
- 6. β-lactams Pharmacology • Absorption: Variable depending on product • Distribution: Widely distributed into tissues and fluids Pens only get into CSF in the presence of inflamed meninges; parenteral 3rd and 4th generation cephs, meropenem, and aztreonam penetrate the CSF • Elimination: most eliminated primarily by the kidney, dosage adj required in the presence of renal insufficiency Nafcillin, oxacillin, ceftriaxone -eliminated by the liver ALL β-lactams have short elimination half-lives except for a few cephalosporins (ceftriaxone)
- 7. β-Lactams Adverse Effects • Hypersensitivity……3 to 10 % Higher incidence with parenteral administration Mild to severe allergic reactions – rash to anaphylaxis and death Antibodies produced against metabolic by- products or penicillin itself Cross-reactivity exists among all penicillins and even other β-lactams
- 8. β-Lactams Adverse Effects • Neurologic – especially with penicillins and carbapenems (imipenem and meropenem) Especially in patients receiving high doses in the presence of renal insufficiency Irritability, confusion, seizures • Hematologic: Leucopenia, neutropenia, thrombocytopenia – prolonged therapy (> 2 weeks)
- 9. β-Lactams Adverse Effects • Gastrointestinal: Nausea, vomiting, diarrhea, pseudomembranous colitis (C. difficile diarrhea) • Interstitial Nephritis: Cellular infiltration in renal tubules (Type IV hypersensitivity reaction – characterized by abrupt increase in serum creatinine; can lead to renal failure Especially with methicillin or nafcillin
- 10. Timeline of antibiotic resistance • 1942 - penicillin available • 1942 - penicillin resistant S. aureus • 1940’s-1950’s - chlorampenicol, tetracycline, erythromycin resistance • Early ‘60s - β-lactamase resistant penicillins available • Late ‘70s - MRSA arose (methicillin resistant S. aureus) • 1997 - first vancomycin resistant Enterococcus reported • July 2002 - CDC reported first case of vancomycin- resistant S. aureus in US
- 11. Natural Penicillins (penicillin G, penicillin V) Gram-positive Gram-negative pen-susc S. aureus Neisseria sp. pen-susc S. pneumoniae Group streptococci Anaerobes viridans streptococci Clostridium sp. Enterococcus Other Treponema pallidum (syphilis)
- 12. Aminopenicillins (ampicillin, amoxicillin) Developed to increase activity against gram-negative aerobes Gram-positive Gram-negative pen-susc S. aureus Proteus mirabilis Group streptococci Salmonella, Shigella viridans streptococci some E. coli Enterococcus sp. H. influenzae Listeria monocytogenes
- 13. Penicillinase-Resistant Penicillins Antistaphylococcal Penicillins (nafcillin, oxacillin, methicillin, cloxacillin, dicloxacillin, flucloxacillin) Developed to overcome the penicillinase enzyme of S. aureus which inactivated natural penicillins Gram-positive methicillin-susceptible S. aureus Group streptococci viridans streptococci
- 14. Carboxypenicillins Antipseudomonal Penicillins (carbenicillin, ticarcillin) Developed to further increase activity against resistant gram-negative aerobes Gram-positive Gram-negative marginal Proteus mirabilis Salmonella, Shigella some E. coli H. influenzae Enterobacter sp. Pseudomonas aeruginosa
- 15. Ureidopenicillins Antipseudomonas Penicillins (piperacillin, azlocillin, mezlocillin) Developed to further increase activity against resistant gram-negative aerobes Gram-positive Gram-negative viridans strep Proteus mirabilis Group strep Salmonella, Shigella some Enterococcus E. coli H. influenzae Anaerobes Enterobacter sp. Fairly good activity Pseudomonas aeruginosa some Klebsiella sp.
- 16. β-Lactamase Inhibitor Combination (Unasyn, Augmentin, Tazosyn) Developed to gain or enhance activity against β-lactamase producing organisms. Gram-positive Gram-negative S. aureus H. influenzae E. coli Anaerobes Proteus sp. Bacteroides sp. Klebsiella sp. Neisseria gonorrhoeae Moraxella catarrhalis
- 17. IV to PO - Penicillins *Penicillin to Penicillin *Ampicillin to Amoxicillin *Unasyn to Augmentin
- 18. Classification and Spectrum of Activity of Cephalosporins • Divided into 4 major groups called “Generations” • Are divided into Generations based on: antimicrobial activity resistance to beta-lactamase
- 19. Classification of Parenteral and Oral Cephalosporins Cephalosporins 1st gen 2nd gen 3rd gen 4th gen *Parenteral Cefazolin Cefamandole Cefoperazone Cefepime Cephalexin Cefuroxime Cefotaxime Cefpirome Cephapirin Ceftazidime Cephradine Ceftriaxone *Oral Cefadroxil Cefaclor Cefdinir Cephalexin Cefprozil Cefpodoxime Cephradine Cefuroxime-axetil Cefixime
- 20. First Generation Cephalosporins Cefadroxil, Cephradine Cefazolin, Cephalexin Best activity against gram-positive aerobes, with limited activity against a few gram-negative aerobes, they are commonly used for management of skin and soft tissue infections. Gram-positive Gram-negative meth-susc S. aureus E. coli pen-susc S. pneumoniae K. pneumoniae Group streptococci Viridans streptococci
- 21. Second Generation Cephalosporins Spectrum of Activity Gram-positive Gram-negative meth-susc S. aureus E. coli pen-susc S. pneumoniae K. pneumoniae Group streptococci P. mirabilis viridans streptococci H. influenzae M. catarrhalis Neisseria sp. They are used to treat respiratory tract infections, urinary tract infections, and soft-tissue infections.
- 22. Third Generation Cephalosporins Spectrum of Activity • In general, are even less active against gram-positive aerobes, but have greater activity against gram-negative aerobes • Ceftriaxone and cefotaxime have the best activity against gram-positive aerobes, including pen-resistant S. pneumoniae
- 23. Third Generation Cephalosporins Spectrum of Activity Gram-negative aerobes: E. coli, K. pneumoniae, Pr. mirabilis, H. influenzae, Mor. catarrhalis, N. gonorrhoeae (including beta-lactamase producing); N. meningitides. Pseudomonas aeruginosa (ceftazidime and cefoperazone) They are used for serious pediatric infections, including meningitis and sepsis
- 24. Fourth Generation Cephalosporins • 4th generation cephalosporins for 2 reasons: Extended spectrum of activity gram-positives: similar to ceftriaxone gram-negatives: similar to ceftazidime, including Pseudomonas aeruginosa; also covers beta-lactamase producing Enterobacter sp. Stability against β-lactamases; poor inducer of extended-spectrum β -lactamases
- 25. Carbapenems (Imipenem, Meropenem) • Most broad spectrum of activity of all antimicrobials • Have activity against gram-positive and gram-negative aerobes and anaerobes • Bacteria not covered by carbapenems include MRSA, VRE, coagulase-negative staph, C. difficile, Nocardia
- 26. • The 1st carbapenem approved for clinical use was imipenem-cilastatin, which has a propensity to cause seizures in children, particularly in the setting of meningitis, and therefore meropenem is more suitable for pediatric use.
- 27. Monobactams Spectrum of Activity Aztreonam bind preferentially to PBP 3 of gram-negative aerobes; has little to no activity against gram-positives or anaerobes Gram-negative E. coli, K. pneumoniae, P. mirabilis, S. marcescens H. influenzae, M. catarrhalis Enterobacter, Citrobacter, Providencia, Morganella Salmonella, Shigella Pseudomonas aeruginosa
- 28. Fluoroquinolones • Novel group of synthetic antibiotics developed in response to growing resistance • The fluorinated quinolones (FQs) represent a major therapeutic advance: Broad spectrum of activity Excellent bioavailability, tissue penetration, prolonged half-lives Overall safety • Disadvantages: resistance, expense
- 29. The Available FQs Older FQs • Norfloxacin (Noroxin®) - PO • Ciprofloxacin (Cipro®) – PO, IV Newer FQs • Levofloxacin (Tavanic®) – PO, IV • Gatifloxacin (Tequin®) – PO, IV now discontinued • Moxifloxacin (Avelox®) – PO, IV
- 30. FQs Spectrum of Activity Gram-positive – newer FQs with enhanced potency • Methicillin-susceptible Staphylococcus aureus • Streptococcus pneumoniae (including PRSP) • Group and viridans streptococci – limited activity • Enterococcus sp. – limited activity
- 31. FQs Spectrum of Activity Gram-Negative – all FQs have excellent activity (cipro=levo>gati>moxi) • Enterobacteriaceae – including E. coli, Klebsiella sp, Enterobacter sp, Proteus sp, Salmonella, Shigella, Serratia marcescens, etc. • H. influenzae, M. catarrhalis, Neisseria sp. • Pseudomonas aeruginosa – significant resistance has emerged; ciprofloxacin and levofloxacin with best activity
- 32. FQs Spectrum of Activity Atypical Bacteria – all FQs have excellent activity against atypical bacteria including: • Legionella pneumophila - DOC • Chlamydia sp. • Mycoplasma sp. • Ureaplasma urealyticum Other Bacteria – Mycobacterium tuberculosis, Bacillus anthracis
- 33. Fluoroquinolones Pharmacology • Concentration-dependent bacterial killing • Absorption Most FQs have good bioavailability after oral administration • Distribution Extensive tissue distribution –liver; lung; skin/soft tissue and bone; urinary tract Minimal CSF penetration • Elimination – renal and hepatic.
- 34. Fluoroquinolones Adverse Effects • Gastrointestinal – 5 % Nausea, vomiting, diarrhea, dyspepsia • Central Nervous System Headache, agitation, insomnia, dizziness, rarely, hallucinations and seizures (elderly) • Hepatotoxicity LFT elevation (led to withdrawal of trovafloxacin) • Phototoxicity (uncommon with current FQs) More common with older FQs (halogen at position 8) • Cardiac Variable prolongation in QTc interval Led to withdrawal of grepafloxacin, sparfloxacin
- 35. Fluoroquinolones Adverse Effects • Articular Damage Arthopathy including articular cartilage damage, arthralgias, and joint swelling Observed in toxicology studies in immature dogs Led to contraindication in pediatric patients and pregnant or breastfeeding women Risk versus benefit Concerns of joint destruction in juvenile animals not seen in humans • Other adverse reactions: tendon rupture, dysglycemias, hypersensitivity
- 36. Pearls - Quinolones Ciprofloxacin: Gram-negative Oral and parenteral fluoroquinolone with best clinical and in vitro data for activity against pseudomonas. Experience is favorable and extensive for nosocomial pneumonia, osteomyelitis, neutropenic fever, travelers diarrhea and UTIs. Now approved for treatment of pediatric UTIs Other fluoroquinolones: Gram-positive (i.e levofloxacin, gatifloxacin, moxifloxacin) have enhanced gram positive activity and are preferred for infections due to S. pneumoniae.
- 37. Dose • Neonates: 10 mg/kg q 12 hr PO or IV. • Children: 15–30 mg/kg/24 hr divided q 12 hr PO or IV; cystic fibrosis: 20–40 mg/kg/24 hr divided q 8–12 hr PO or IV. • Adults: 250–750 mg q 12 hr; 200–400 mg IV q 12 hr PO (max dose: 1.5 g/24 hr
- 38. Macrolides • Erythromycin is a naturally-occurring macrolide derived from Streptomyces erythreus – problems with acid lability, narrow spectrum, poor GI intolerance, short elimination half-life • Structural derivatives include clarithromycin and azithromycin: Broader spectrum of activity Improved PK properties – better bioavailability, better tissue penetration, prolonged half-lives Improved tolerability
- 39. Macrolides Mechanism of Action Inhibits protein synthesis by reversibly binding to the 50S ribosomal subunit Suppression of RNA-dependent protein synthesis Macrolides typically display bacteriostatic activity, but may be bactericidal when present at high concentrations against very susceptible organisms
- 40. Macrolide Spectrum of Activity Gram-Positive Aerobes – erythromycin and clarithromycin display the best activity (Clarithro>Erythro>Azithro) • Methicillin-susceptible Staphylococcus aureus • Streptococcus pneumoniae (only PSSP) – resistance is developing • Group and viridans streptococci • Bacillus sp., Corynebacterium sp.
- 41. Macrolide Spectrum of Activity Gram-Negative Aerobes – newer macrolides with enhanced activity (Azithro>Clarithro>Erythro) H. influenzae (not erythro), M. catarrhalis, Neisseria sp. DO NOT HAVE ACTIVITY AGAINST ANY ENTEROBACTERIACEAE
- 42. Macrolide Spectrum of Activity Anaerobes – activity against upper airway anaerobes Atypical Bacteria – all macrolides have excellent activity against atypical bacteria including: • Legionella pneumophila • Chlamydia sp. • Mycoplasma sp. • Ureaplasma urealyticum Other Bacteria – Mycobacterium avium complex, Treponema pallidum, Campylobacter, Borrelia, Bordetella, Brucella. Pasteurella
- 43. Macrolides Pharmacology Absorption Erythromycin – variable absorption (15-45%); food may decrease the absorption • Base: destroyed by gastric acid; enteric coated • Esters and ester salts: more acid stable Clarithromycin – acid stable and well-absorbed, 55% bioavailable regardless of presence of food Azithromycin –acid stable; 38% bioavailable; food decreases absorption of capsules
- 44. Macrolides Pharmacology Distribution Extensive tissue and cellular distribution – clarithromycin and azithromycin with extensive penetration Minimal CSF penetration Elimination Clarithromycin is the only macrolide partially eliminated by the kidney (18% of parent and all metabolites); requires dose adjustment when CrCl < 30 ml/min Hepatically eliminated: ALL NONE of the macrolides are removed during hemodialysis! Variable elimination half-lives (1.4 hours for erythro; 3 to 7 hours for clarithro; 68 hours for azithro)
- 45. Macrolides Adverse Effects • Gastrointestinal – up to 33 % Nausea, vomiting, diarrhea, dyspepsia Most common with erythro; less with new agents • Cholestatic hepatitis - rare > 1 to 2 weeks of erythromycin estolate • Thrombophlebitis – IV Erythro and Azithro Dilution of dose; slow administration • Other: ototoxicity (high dose erythro in patients with RI); QTc prolongation; allergy
- 46. Macrolides Drug Interactions Erythromycin and Clarithromycin ONLY– are inhibitors of cytochrome p450 system in the liver; may increase concentrations of: Theophylline Digoxin, Carbamazepine Valproic acid Cyclosporine Terfenadine, Astemizole Phenytoin Warfarin Ergot alkaloids
- 47. Aminoglycosides Mechanism of Action • Multifactorial, but ultimately involves inhibition of protein synthesis • Irreversibly bind to 30S ribosomes – must bind to and diffuse through outer membrane and cytoplasmic membrane and bind to the ribosome – disrupt the initiation of protein synthesis, decreases overall protein synthesis, and produces misreading of mRNA • Are bactericidal
- 48. Aminoglycosides Spectrum of Activity Gram-Positive Aerobes most S. aureus and coagulase-negative staph viridans streptococci Enterococcus sp. Gram-Negative Aerobes (not streptomycin) E. coli, K. pneumoniae, Proteus sp. Acinetobacter, Citrobacter, Enterobacter sp. Morganella, Providencia, Serratia, Salmonella, Shigella Pseudomonas aeruginosa (amik>tobra>gent) Mycobacteria – tuberculosis - streptomycin – atypical - streptomycin or amikacin
- 49. Aminoglycosides Pharmacology • Absorption - poorly absorbed from GI tract • Distribution – primarily in extracellular fluid volume; are widely distributed into body fluids but NOT the CSF • Elimination – eliminated unchanged by the kidney via glomerular filtration; 85-95% of dose – elimination half-life dependent on renal function normal renal function - 2.5 to 4 hours impaired renal function - prolonged
- 50. Aminoglycosides Adverse Effects Nephrotoxicity – nonoliguric azotemia due to proximal tubule damage; increase in BUN and serum Cr; reversible if caught early – risk factors: long duration of therapy (> 2 weeks), underlying renal dysfunction, elderly, other nephrotoxins Ototoxicity – 8th cranial nerve damage - vestibular and auditory toxicity; irreversible and saturable – vestibular: dizziness, vertigo, ataxia – auditory: tinnitus, decreased hearing – risk factors: same as for nephrotoxicity
- 51. Sulfonamides • Spectrum includes: Staph, H. influenzae, Mor. catarrhalis. Generally not effective vs. other microbes. • Mechanism: acts on protein synthesis chain • Combined with erythromycin : it is as effective as amoxcillin in treating AOM. • Sulfonamide + Trimethoprim is alternate 1st line agent for AOM. Both drugs act on protein chain—synergistic. Effective vs. beta- lactamase producing bacteria.
- 52. Vancomycin Mechanism of Action • Inhibits bacterial cell wall synthesis at a site different than beta-lactams • Inhibits synthesis and assembly of the second stage of peptidoglycan polymers • Bactericidal (except for Enterococcus)
- 53. Vancomycin Spectrum of Activity Gram-positive bacteria – Methicillin-Susceptible AND Methicillin-Resistant S. aureus and coagulase-negative staphylococci – Streptococcus pneumoniae (including PRSP), viridans streptococcus, Group streptococcus – Enterococcus sp. – Corynebacterium, Bacillus. Listeria, Actinomyces – Clostridium sp. (including C. difficile), Peptococcus, Peptostreptococcus No activity against gram-negative aerobes or anaerobes
- 54. Vancomycin Pharmacology • Absorption – absorption from GI tract is negligible after oral administration except in patients with intense colitis – Use IV therapy for treatment of systemic infection • Distribution – widely distributed into body tissues and fluids, including adipose tissue. – inconsistent penetration into CSF, even with inflamed meninges • Elimination – primarily eliminated unchanged by the kidney via glomerular filtration – elimination half-life depends on renal function
- 55. Vancomycin Clinical Uses • Infections due to methicillin-resistant staph including bacteremia, empyema, endocarditis, peritonitis, pneumonia, skin and soft tissue infections, osteomyelitis • Serious gram-positive infections in β-lactam allergic patients • Infections caused by multidrug resistant bacteria. • Endocarditis or surgical prophylaxis in select cases. • Oral vancomycin for refractory C. difficile colitis.
- 56. ***DOSE: • Children: 45–60 mg/kg/24 hr divided q 8–12 hr IV; • Clostridium difficile-associated colitis; 40–50 mg/kg/24 hr divided q 6–8 hr PO. • Adults: 0.5–1 g IV q 12 hr IV.
- 57. S. aureus Penicillin [1950s] Penicillin-resistant S. aureus Evolution of Drug Resistance in S. aureus Methicillin [1970s] Methicillin- resistant S. aureus (MRSA) Vancomycin-resistant enterococci (VRE) Vancomycin [1990s] [1997] Vancomycin intermediate- resistant S. aureus (VISA) [ 2002 ] Vancomycin- resistant S. aureus
- 58. Vancomycin Adverse Effects Red-Man Syndrome – flushing, pruritus, erythematous rash on face and upper torso – related to RATE of intravenous infusion; should be infused over at least 60 minutes – resolves spontaneously after discontinuation – may lengthen infusion (over 2 to 3 hours) or pretreat with antihistamines in some cases
- 59. Vancomycin Adverse Effects • Nephrotoxicity and Ototoxicity – rare with monotherapy, more common when administered with other nephro- or ototoxins – risk factors include renal impairment, prolonged therapy, high doses, ? high serum concentrations, other toxic meds • Dermatologic - rash • Hematologic - neutropenia and thrombocytopenia with prolonged therapy • Thrombophlebitis
- 60. Oxazolidinones • Linezolid (Zyvox®) is the first available agent which received FDA approval in April 2000; available PO and IV • Developed in response to need for agents with activity against resistant gram- positives (MRSA, VRE)
- 61. Linezolid Mechanism of Action • Binds to the 50S ribosomal subunit near to surface interface of 30S subunit – causes inhibition of 70S initiation complex which inhibits protein synthesis • Bacteriostatic (cidal against some bacteria)
- 62. Linezolid Spectrum of Activity Gram-Positive Bacteria – Methicillin-Susceptible, Methicillin-Resistant AND Vancomycin-Resistant Staph aureus and coagulase- negative staphylococci – Streptococcus pneumoniae (including PRSP), viridans streptococcus, Group streptococcus – Enterococcus faecium AND faecalis (including VRE) – Bacillus. Listeria, Clostridium sp. (except C. difficile), Peptostreptococcus, P. acnes Gram-Negative Aerobes – relatively inactive Atypical Bacteria – Mycoplasma, Chlamydia, Legionella
- 63. Linezolid Pharmacology • Concentration-independent bactericidal activity • Absorption – 100% bioavailable • Distribution – readily distributes into well- perfused tissue; CSF penetration ≈ 70% • Elimination – both renally and nonrenally, but primarily metabolized; t½ is 4.4 to 5.4 hours; no adjustment for RI; not removed by HD
- 64. Linezolid Adverse Effects • Gastrointestinal – nausea, vomiting, diarrhea (6 to 8 %) • Headache – 6.5% • Thrombocytopenia – 2 to 4% – Most often with treatment durations of > 2 weeks – Therapy should be discontinued – platelet counts will return to normal
- 65. Clindamycin Mechanism of Action Inhibits protein synthesis by binding exclusively to the 50S ribosomal subunit Binds in close proximity to macrolides – competitive inhibition Clindamycin typically displays bacteriostatic activity, but may be bactericidal when present at high concentrations against very susceptible organisms
- 66. Clindamycin Spectrum of Activity Gram-Positive Aerobes • Methicillin-susceptible Staphylococcus aureus (MSSA only) • Streptococcus pneumoniae (only PSSP) – resistance is developing • Group and viridans streptococci
- 67. Clindamycin Spectrum of Activity Anaerobes Peptostreptococcus some Bacteroides sp Actinomyces Prevotella sp. Propionibacterium Fusobacterium Clostridium sp. (not C. difficile) Other Bacteria – Toxoplasmosis gondii, Malaria
- 68. Clindamycin Pharmacology Absorption – available IV and PO Rapidly and completely absorbed (90%); food with minimal effect on absorption Distribution Good serum concentrations with PO or IV Good tissue penetration including bone; minimal CSF penetration Elimination Clindamycin primarily metabolized by the liver; half- life is 2.5 to 3 hours Clindamycin is NOT removed during hemodialysis
- 69. Clindamycin Adverse Effects • Gastrointestinal – 3 to 4 % Nausea, vomiting, diarrhea, dyspepsia • C. difficile colitis – one of worst offenders Mild to severe diarrhea Requires treatment with metronidazole • Hepatotoxicity - rare Elevated transaminases • Allergy - rare
- 70. Agents for Infections Due to Gram Positive BacteriaStaph.epidermidis MRSA Staph.aureus Streptococci (GroupAandGroupB) GNR RGNR Pseudomonasaeruginosa Penicillin G Penicillin V Anti staph penicillin: Methicillin, Oxacillin, Nafcillin Dicloxacillin, Cloxacillin, Cloxacillin Vancomycin Linezolid
- 71. Broad and Extended Spectrum PenicillinsStaph.epidermidis MRSA Staph.aureus Streptococci (GroupAandGroupB) GN RGN Pseudomonasaeruginosa Ampicillin Amoxicillin Carbenicillin, Mezlocillin, Piperacillin, Ticarcillin Ticarcillin + Clavulanic Acid = Timentin ®, Piperacillin + Tazobactam = Tazosyn® Ampicillin + Sulbactam = Unasyn® Amoxicillin + Clavulanic Acid = Augmentin®
- 72. CephalosporinsStaph.epidermidis MRSA Staph.aureus Streptococci (GroupAandGroupB) GNR RGNR Pseudomonasaeruginosa Cefazolin Cephalexin, Cefadroxil Cefepime Cefuroxime, Cefoxitin Cefaclor, Loracarbef, Ceftibuten Cefprozil, Cefuroxime axetil, Cefpodoxime, Ceftriaxone, Cefotaxime Cefdinir Cefixime Cefoperazone & Ceftazidime 1st Generation 2nd Generation 3rd Generation 4th Generation
- 73. Macrolides, Azalides and KetolidesStaph.epidermidis MRSA Staph.aureus Streptococci (GroupAandGroupB) GNR RGNR Pseudomonasaeruginosa Erythromycin Clarithromycin, Azithromycin, Telithromycin
- 74. Broad Spectrum AntibioticsStaph.epidermidis MRSA Staph.aureus Streptococci (GroupAandGroupB) GNR RGNR Pseudomonasaeruginosa Ciprofloxacin, Levofloxacin, Moxifloxacin, Gatifloxacin Tetracycline, Doxycycline, Minocycline Gentamicin, Tobramycin, Netilmicin, Amikacin Imipenem, Meropenem Trimethoprim/Sulfamethoxazole