Rationalism of antibiotic therapy copy


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Rationalism of antibiotic therapy copy

  1. 1. Rationalism InAntibiotic Therapy Dr.T.V.Rao MD Dr.T.V.Rao MD 1
  2. 2. Fleming and Penicillin Dr.T.V.Rao MD 2
  3. 3. Antibiotic brands• 50 penicillins • 9 macrolides• 71 cephalosporins • 2 streptogramins• 12 tetracyclines • 3 dihydrofolate• 8 aminoglycosides reductase• 1 monobactam inhibitors• 5 Carbapenems • 1 oxazolidinone • 5.5 quinolones Dr.T.V.Rao MD 3
  4. 4. Development of anti-microbials ertapenem tigecyclinThe development daptomicin linezolid of anti-infectives … telithromicin quinup./dalfop. cefepime ciprofloxacin aztreonam norfloxacin imipenem cefotaxime clavulanic ac. cefuroxime gentamicin cefalotina nalidíxico ac. ampicillin methicilin vancomicin rifampin chlortetracyclin streptomycin pencillin G prontosil 1920 1930 1940 1950 1960 Dr.T.V.Rao MD 1970 1980 1990 2000 4
  5. 5. 1962 and 2000, no major classes of antibiotics were introduced Fischbach MA and Walsh CT Science 2009 Dr.T.V.Rao MD 5
  6. 6. Antibiotics• Biology and Society About 50% of the antibiotics produced today are used in the livestock industry. What impact does this have on the treatment of human diseases? Dr.T.V.Rao MD 6
  7. 7. ANTIMICROBIAL RESISTANCE: The role of animal feed antibiotic additives• 48% of all antibiotics by weight is added to animal feeds to promote growth. Results in low, sub therapeutic levels which are thought to promote resistance.• Farm families who own chickens feed tetracycline have an increased incidence of tetracycline resistant fecal flora Dr.T.V.Rao MD 7
  8. 8. Prescribing an antibiotic Is an antibiotic necessary ? What is the most appropriate antibiotic ? What dose, frequency, route and duration ? Is the treatment effective ? Dr.T.V.Rao MD 8
  9. 9. How are antibiotics overused or misused?• Seven out of ten Americans receive antibiotics when they seek treatment for a common cold! Only one-third of patients use antibiotics the way doctors tell them.• .This allows bacteria to become resistant by not killing them completely. Dr.T.V.Rao MD 9
  10. 10. Antibiotic Prescribing Children are real Concern• Antibiotics were prescribed in 68% of acute respiratory tract visits – and of those, 80% were unnecessary according to CDC guidelines• Children are of particular concern because they have the highest rates of Dr.T.V.Rao MD 10 antibiotic use.
  11. 11. We too Contribute for Creating Drug Resistance • Every time a person takes antibiotics, sensitive bacteria are killed, but resistant microbes may be left to grow and multiply. Repeated and improper uses of antibiotics are primary causes of the increase in drug-resistant Dr.T.V.Rao MD bacteria. 11
  12. 12. The consequences of antibiotic resistance • Increased morbidity & mortality – “best-guess” therapy may fail with the patient’s condition deteriorating before susceptibility results are available – no antibiotics left to treat certain infections • Greater health care costs – more investigations – more expensive, toxic antimicrobials required – expensive barrier nursing, isolation, procedures, etc. • Therapy priced out of the reach of some third-world countries12 Dr.T.V.Rao MD
  13. 13. Costs Associated with Increased Bacterial Resistance• ↑Treatment failures• ↑Morbidity and mortality• ↑Risk of hospitalization• ↑Length of hospital stays• ↑Need for expensive and broad spectrum antibiotics Dr.T.V.Rao MD 13
  14. 14. Social factors fuelling resistance • Poverty encourages the development of resistance through under use of drugs – Patients unable to afford the full course of the medicines – Sub-standard & counterfeit drugs lack potency • In wealthy countries, resistance is emerging for the opposite reason – the overuse of drugs. – Unnecessary demands for drugs by patients are often eagerly met by health services and stimulated by pharmaceutical promotion – Overuse of antimicrobials in food production is also contributing to increased drug resistance. Currently, 50% of all antibiotic production is used in animal husbandry and aquiculture • Globalization, increased travel and trade ensure that resistant strains quickly travel elsewhere. So does excessive promotion.14 Dr.T.V.Rao MD
  15. 15. Classification of Pencillins• Natural Benzyl penicillin Phenoxymethyl penicillin Penicillin v Semi synthetic and pencillase resistant 1 Methicillin 2 Nafcillin 3 Cloxacillin 4 Oxacillin 5 Floxacillin Dr.T.V.Rao MD 15
  16. 16. Macrolides,Azalides,Ketolides• Contain macro cyclic lactone ring Erythromycin. Is popularly used drug• Other drugs Roxithromycin,Azithromy cin• Inhibits the protein synthesis.• Used as alternative to pencillin allergy patients. Dr.T.V.Rao MD 16
  17. 17. Dr.T.V.Rao MD 17
  18. 18. Cephalosporins• Like penicillin acts similar• Products of the molds of genus Cephalosporium except cefoxilin• Divided into 4 generation of Cephalosporins depending on the spectrum of activity. Dr.T.V.Rao MD 18
  19. 19. Major generations of Cephalosporins• Cephalosporins are divided into 3 generations:• 1st generation: Cephalexin, cefadroxil, cephradine• 2nd generation: Cefuroxime, cofactor• 3rd generation: cefotaxime, Ceftazidime, cefepime - these give the best CNS penetration• 4th generation Cephalosporins are already available Dr.T.V.Rao MD 19
  20. 20. Different Generations of Cephalosporins• Cephalosporins are grouped into "generations" based on their spectrum of antimicrobial activity. The first Cephalosporins were designated first generation while later, more extended spectrum Cephalosporins were classified as second generation Cephalosporins. Dr.T.V.Rao MD 20
  21. 21. 5th Generation Cephalosporins• Ceftaroline is a new intravenous (IV) cephalosporin that was FDA-approved October 2010. It is labelled for the treatment of adults with infections caused by susceptible bacteria, specifically skin and skin structure infections (SSSIs) caused by methicillin- sensitive Dr.T.V.Rao MD 21
  22. 22. 5th Generation Cephalosporins• Staphylococcus aureus (MSSA), methicillin- resistant S aureus (MRSA), Streptococcus pyogenes, Streptococcus agalactiae, Escherichia coli, Klebsiella pneumoniae, or Klebsiella oxytoca; and community acquired pneumonia (CAP) caused by Streptococcus pneumoniae (with or without concurrent bacteraemia), MSSA, E coli, Haemophilus influenza, K.pneumoniae, or K oxytoca Dr.T.V.Rao MD 22
  23. 23. Ceftaroline is effective …• Ceftaroline is a fifth generation cephalosporin with excellent activity against GPCs including MRSA & DRSP Affinity for all PBPs including PBP 2’ and PBP 2X Not ESBL stable, Not active against Non fermenters Dr.T.V.Rao MD 23
  24. 24. Advantages with Newer generations• Each newer generation of cephalosporins has significantly greater gram-negative antimicrobial properties than the preceding generation, in most cases with decreased activity against gram-positive organisms. Fourth generation cephalosporins, however, have true broad spectrum activity Dr.T.V.Rao MD 24
  25. 25. Other Beta-lactams include• Other beta-lactams include:• Aztreonam: a monocytic beta- lactam, with an antibacterial spectrum which is active only against Gram negative aerobes, including Pseudomonas aeruginosa, Neisseria meningitides and N. gonorrhoea. Dr.T.V.Rao MD 25
  26. 26. Advantages with Newer generations• Each newer generation of cephalosporins has significantly greater gram-negative antimicrobial properties than the preceding generation, in most cases with decreased activity against gram-positive organisms. Fourth generation cephalosporins, however, have true broad spectrum MD Dr.T.V.Rao activity 26
  27. 27. How are Carbapenems Used?Uses by Clinical Syndrome Use by Clinical Isolate• Bacterial meningitis  Acinetobacter spp.  Pseudomonas aeruginosa• Hospital-associated  Alcaligenes spp. sinusitis  Enterobacteriaceae• Sepsis of unknown origin  Mogenella spp.• Hospital-associated  Serratia spp. pneumonia  Enterobacter spp.  Citrobacter spp.  ESBL or AmpC + E. coli and Klebsiella spp. Reference: Sanford Guide MD Dr.T.V.Rao 27
  28. 28. Spectrum of Activity Strep spp. & Entero- Non-Drug Anaerobes MSSA bacteriaeae fermentorsImipenem + + + +Meropenem + + + + LimitedErtapenem + + activity +Doripenem + + + +
  29. 29. Emerging Carbapenem Resistance in Gram-Negative Bacilli• Significantly limits treatment options for life-threatening infections• No new drugs for gram-negative bacilli• Emerging resistance mechanisms, carbapenemases are mobile,• Detection of carbapenemases and implementation of infection control practices are necessary to limit spread Dr.T.V.Rao MD 29
  30. 30. Other drugs• Imipenem: a carbapenem with a broader spectrum of activity against Gram positive and negative aerobes and anaerobes. Needs to be given with cilastatin to prevent inactivation by the kidney. Dr.T.V.Rao MD 30
  31. 31. Quinolones• Quinolones are the first wholly synthetic antimicrobials. The commonly used Quinolones.• Act on the DNA gyrase which prevents DNA polymerase from proceeding at the replication fork and consequently stopping synthesis. Dr.T.V.Rao MD 31
  32. 32. Activity of New Fluoroquinolones Against MRSA, VRE and PRSP MRSA VRE PRSP QTc change Levofloxacin +/- +/- ++ 4.6 msc Gatifloxacin +/- +/- ++++ 2.9 msc Moxifloxacin +/- +/- ++++ 6 msc Gemifloxacin +/- +/- ++++ 5 msc Ciprofloxacin +/--- +/--- +/--- ? Dr.T.V.Rao MD 32
  33. 33. Aminoglycosides• Aminoglycosides are group of antibiotics in which amino sugars liked by glycoside bonds• Eg Streptomycin,• Act at the level of Ribosomes and inhibits protein synthesis• Other Aminoglycosides – Gentamycin, neomycins,paromomycins,tobr amycins Kanamycins and spectinomycins Dr.T.V.Rao MD 33
  34. 34. Dr.T.V.Rao MD 34
  35. 35. Tetracyclines• Broad spectrum antibiotic produced by Streptomyces species• 1. Oxytetracycle, chlortetracycle and tetracycline• Tetracyclnes are bacteriostatic drugs inhibits rapidly multiplying organisms• Resistance develops slowly and attributed to alterations in cell membrane permeability to enzymatic inactivation of the drug Dr.T.V.Rao MD 35
  36. 36. Other Antimicrobial agents• Lincomycins Clindamycin resembles Macrolides in biting site and antimicrobial activity. Streptogramins Quinpristin / dalfopristin useful in gram positive bacteria Dr.T.V.Rao MD 36
  37. 37. Antibiotics in Anaerobes• Major anaerobes – Anaerobic cocci, clostridia and Bactericides are susceptible to Benzyl pencillin• Bact.fragilis as well as many other anaerobes are treatable with Erythromycin,Lincomycin, tetracycline and Chloramphenicol• Clindamycin is effective against many strains of Bacteroides Dr.T.V.Rao MD 37
  38. 38. Metronidazole in Anaerobic Infections• Since the discovery of Metronidazole in 1973 since then it was identified as leading agent anaerobes.• But also useful in treating parasitic infections Trichomonas, Amoebiasis and other protozoan infections. Dr.T.V.Rao MD 38
  39. 39. Dr.T.V.Rao MD 39
  40. 40. Drug Resistance• In spite discovery of several antibiotics several microorganisms attained resistance.• The major factor contributing to persistence of infectious disease has been the tremendous capacity of microorganisms for circumventing the action of inhibitory drugs.• The drug resistance continues to be a threat for usefulness of the chemotherapeutic agents. Dr.T.V.Rao MD 40
  41. 41. Inappropriate Antibiotic Use Use of antibiotics with no clinical indication (eg, for viral infections) Use of broad spectrum antibiotics when not indicated Inappropriate choice of empiric antibiotics Dr.T.V.Rao MD 41
  42. 42. Multi Drug resistant pathogens• If a bacterium carries several resistance genes, it is called multiresistant or, informally, a superbug. The term antimicrobial resistance is sometimes use to explicitly encompass organisms other than bacteria MD Dr.T.V.Rao 42
  43. 43. Extended-Spectrum β-Lactamases• β-lactamases capable of conferring bacterial resistance to – the penicillins – first-, second-, and third-generation cephalosporins – aztreonam – (but not the cephamycins or carbapenems)• These enzymes are derived from group 2b β-lactamases (TEM-1, TEM-2, and SHV-1) – differ from their progenitors by as few as one AA Dr.T.V.Rao MD 43
  44. 44. Antibiotic Resistance Threat to Humans and Animals• Antibiotic resistance has become a serious problem in both developed and underdeveloped nations. By 1984 half of those with active tuberculosis in the United States had a strain that resisted at least one antibiotic. In certain settings, such as hospitals and some childcare location Dr.T.V.Rao MD 44
  45. 45. Carbapenemases• Ability to hydrolyze penicillins, cephalosporins, monobactams, and carbapenems• Resilient against inhibition by all commercially viable ß- lactamase inhibitors – Subgroup 2df: OXA (23 and 48) carbapenemases – Subgroup 2f : serine carbapenemases from molecular class A: GES and KPC – Subgroup 3b contains a smaller group of MBLs that preferentially hydrolyze carbapenems • IMP and VIM enzymes that have appeared globally, most frequently in non-fermentative bacteria but also in Enterobacteriaceae Dr.T.V.Rao MD 45
  46. 46. K. pneumonia carbapenemases)• KPCs are the most prevalent of this group of enzymes, found mostly on transferable plasmids in K. pneumonia• Substrate hydrolysis spectrum includes cephalosporins and carbapenems Dr.T.V.Rao MD 46
  47. 47. Consequences of Antibiotic drug Resistance• People infected with drug-resistant organisms are more likely to have longer and more expensive hospital stays, and may be more likely to die as a result of the infection. They require treatment with second- or third- choice drugs that may be less effective, more toxic, and more expensive. This means that patients with an antimicrobial-resistant infection may suffer more and pay more for treatment. (Issues with Insurance) Dr.T.V.Rao MD 47
  48. 48. Emerging Trends in Antibiotic Resistance• Reports of methicillin-resistant Staphylococcus aureus (MRSA)—a potentially dangerous type of staph bacteria that is resistant to certain antibiotics and may cause skin and other infections—in persons with no links to healthcare systems have been observed with increasing frequency in the United States and elsewhere around the globe. Dr.T.V.Rao MD 48
  49. 49. Gram negative bacteria a great threat • Multi-drug resistant Klebsiella species and Escherichia coli have been isolated in hospitals throughout the United States. • It is a Universal phenomenon Dr.T.V.Rao MD 49
  50. 50. Fungi too becoming resistant• Antimicrobial resistance is emerging among some fungi, particularly those fungi that cause infections in transplant patients with weakened immune systems. Dr.T.V.Rao MD 50
  51. 51. Resistance in Virus • Antimicrobial resistance has also been noted with some of the drugs used to treat human immunodeficiency virus (HIV) infections and influenza. Dr.T.V.Rao MD 51
  52. 52. Parasites too are Problematic• The development of antimicrobial resistance to the drugs used to treat malaria infections has been a continuing problem in many parts of the world for decades. Antimicrobial resistance has developed to a variety of other parasites that cause infection.• Dr.T.V.Rao MD 52
  53. 53. Identification of The Etiological Agent  Laboratory diagnosis Interpretation of the report What is isolated is not necessarily the pathogen Was the specimen properly collected ? Is it a contaminant or colonizer ? Sensitivity reports are at best a guide Dr.T.V.Rao MD 53
  54. 54. Limitations of combination of antibiotics• The role of combination antimicrobial therapy for the prevention of resistance is limited to those situations in which there is A high organism load A high frequency of mutational resistance during therapy.• Classic examples are tuberculosis or HIV infection. Dr.T.V.Rao MD 54
  55. 55. Problems With Improper Use of Antibiotics• They don’t help the patient at all• Expense: 75% of outpatient antibiotics are used for respiratory infections• Patient expectations: why no better?• Side effects: diarrhea, rash, allergy• Development of resistance: the antibiotic won’t work when you really DO need it for a bacterial infection Dr.T.V.Rao MD 55
  56. 56. WHO global strategy on reducing the antibiotic resistance• The WHO Global Strategy for Containment of Antimicrobial Resistance identifies the establishment and support of microbiology laboratories as a fundamental priority in guiding and assessing intervention efforts. Dr.T.V.Rao MD 56
  57. 57. Importance of local antibiotic Resistance data Resistance patterns vary  From country to country  From hospital to hospital in the same country  From unit to unit in the same hospital Regional/Country data useful only for looking at trends NOT guide empirical therapy Dr.T.V.Rao MD 57
  58. 58. Streamlining or De-Escalation of Therapy–On the basis of culture and sensitivity reports we can more effectively target the causative pathogens, by elimination of redundant combination therapy–Resulting in decreased Ab exposure and substantial cost savings Dr.T.V.Rao MD 58
  59. 59. Continuous Medical Education• Training and educating a Must .. health care professionals on the appropriate use of antibiotics must include appropriate selection, dosing, route, and duration of antibiotic therapy. To ensure that training and education is working, there should be extensive collaboration between the antibiotic stewardship and hospital infection prevention and control teams. Dr.T.V.Rao MD 59
  60. 60. Antibiotic Pressure and Resistance in Bacteria What factors promote their development and spread ? Alteration of normal flora Practices contributing to misuse of antibiotics Settings that foster drug resistance Failure to follow infection control principles Dr.T.V.Rao MD 60
  61. 61. Practices Contributing to Misuse of Antibiotics Inappropriate specimen selection and collection Inappropriate clinical tests Failure to use stains/smears Failure to use cultures and susceptibility tests Dr.T.V.Rao MD 61
  62. 62. Settings that Foster Drug Resistance Hospital Intensive care units Oncology units Dialysis units Rehab units Transplant units Burn units Dr.T.V.Rao MD 62
  63. 63. Implementation of WHONET CAN HELP TO MONITOR RESISTANCE • Legacy computer systems, quality improvement teams, and strategies for optimizing antibiotic use have the potential to stabilize resistance and reduce costs by encouraging heterogeneous prescribing patterns and use of local susceptibility patterns to inform empiric treatment. Dr.T.V.Rao MD 63
  64. 64. Drugs Under Development PRSP, MRSA,VISA,VRE• Lipopetides (Daptomycin: narrow therapeutic index)• Glycyclines• Glycopeptides (Vancomycin analogues)• Fluoroquinolones• Macrolides/Ketolides• Evernimicin (trials on hold) Dr.T.V.Rao MD 64
  65. 65. Physicians Can Impact Other cliniciansPatientsOptimize patient evaluation Optimize consultations withAdopt judicious antibiotic other cliniciansprescribing practices Use infection control measuresImmunize patients Educate others about judicious use of antibiotics Dr.T.V.Rao MD 65
  66. 66. A good clinical practice saves antibiotics• Treatment should be limited to bacterial infections, using antibiotics directed against the causative agent, given in optimal dosage, interval and length of treatment, with steps taken to ensure maximum patient compliance with the treatment regimen and only when the benefit of treatment outweighs the Dr.T.V.Rao MD 66
  67. 67. Continuous Medical Education a Must ..• Training and educating health care professionals on the appropriate use of antibiotics must include appropriate selection, dosing, route, and duration of antibiotic therapy. To ensure that training and education is working, there should be extensive collaboration between the antibiotic stewardship and hospital infection prevention and control teams Dr.T.V.Rao MD 67
  68. 68. Are we overusing Antibiotics Dr.T.V.Rao MD 68
  69. 69. Good hand washing practices still reduces antibiotic resistance and spread Dr.T.V.Rao MD 69
  70. 70. Conclusions Antibiotic resistance is a major problem world-wide Resistance is inevitable with use No new class of antibiotic introduced over the last two decades  Appropriate use is the only way of prolonging the useful life of an antibiotic Dr.T.V.Rao MD 70
  71. 71. Antibiotics save LivesSave Antibiotics from Misuse Dr.T.V.Rao MD 71
  72. 72. • Programme Created by Dr.T.V.Rao MD for Medical andParamedical Professionals in the Developing World • Email • doctortvrao@gmail.com Dr.T.V.Rao MD 72