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CHEMOTHERAPEUTICS OF INFECTIOUS DISEASES Anton Kohút.

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Presentation on theme: "CHEMOTHERAPEUTICS OF INFECTIOUS DISEASES Anton Kohút."— Presentation transcript:

1 CHEMOTHERAPEUTICS OF INFECTIOUS DISEASES Anton Kohút

2 Basic terminology antibacterial spectrum MIC resistance dysmicrobia superinfection bactericidal effect bacteriostatic effect

3 Basic criteria for ATB maximal microbial toxicity minimal organ toxicity

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5 Mechanism of ATB action 1 2 3 4 ab a b

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7 Mechanisms of action interference with cell wall synthesis (  -lactams, vancomycin, cycloserin) influence of cell membrane (polymyxines) interference with protein synthesis (CMP, TTC, AMG, macrolides) interference with nucleic acid metabolism (grizeofulvin, rifampicin, quinolones) interference with intermediary metabolism (sulfonamides)

8 Resistance Is antibiotic resistance inevitable?

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10 Mechanisms of resistance enzymes change of cell wall permeability ↑ synthesis of antagonist (folic acid) change of penicilin-binding protein (PBP) Resistance to antibiotics occurs through four general mechanisms: target modification; efflux; immunity and bypass; and enzyme-catalyzed destruction

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12 In the past two decades we have witnessed: the rise of so-called extended spectrum β- lactamases (ESBLs), which are mutants of enzymes that previously could only inactivate penicillins but now have gained activity against many cephalosporins; carbapenemases such as KPC and NDM-1 that inactivate all β-lactam antibiotics;

13 plasmid-mediated (and thus horizontally disseminated) resistance to fluoroquinolone antibiotics; the spread of virulent MRSA (methicillin-resistant Staphylococcus aureus) in the community; the rise of multi-drug resistant Neisseria gonorrhoea; the emergence and global dissemination of multi-drug resistant Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae and Enterobacteriaceae; the spread of extensively drug resistant Mycobacterium tuberculosis; resistance to the two newest antibiotics to be approved for clinical use - daptomycin and linezolid.

14 The discovery of antibiotic classes

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16 Toxic effects of ATB

17 myelosuppresion (CMP) hematotoxicity (sulfonamides) hepatotoxicity (macrolides) nephrotoxicity (aminoglycosides) ototoxicity (aminoglycosides) neurotoxicity (anti-TBC)

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19 Other side effects (SE) allergy (  -lactams) dysmicrobia (large spectrum ATB) superinfection (large spectrum ATB) Jarisch-Herxheimer (PNC) sy Hoigné (PNC-retard)

20 Jarisch-Herxheimer

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22 Combinations of ATB

23 Aims: increase of therapeutic effect decrease in SE prophylaxis of resistance Bacteriostatic (with rapid onset) + bactericidal  NEVER !

24 Principles of ATB therapy

25 primary focus inf. possible inf. agent sensitivity variability of pacient´s response kinetics  penetration hospitalisation ATB SE effectiveness of elimination organs start therapy in right time regular dosing optimal ther. period don´t repeat therapy price of ATB

26 Bacteria by Site of Infection

27 Inhibitors of cell wall synhesis  -lactams

28 Alexander Fleming, 1928

29 Penicillins basic PNC anti-staphyloccocal aminoPNC carboxyPNC acylureidoPNC carbapenems monobactams  -lactamase inhib.

30 Penicillins (bactericidal) Penicillium notatum 6-aminopenicillanic acid penem

31 Basic PNC benzylpenicilline – PNC G procain-benzyl-PNC benzatine-PNC phenoxymethyl-PNC penamecilline

32 Natural Penicillins (penicillin G, penicillin VK) Gram-positive Gram-negative pen-susc S. aureusNeisseria sp. pen-susc S. pneumoniae Group streptococci Anaerobes viridans streptococciAbove the diaphragm EnterococcusClostridium sp. Other Treponema pallidum (syphilis)

33 Penicillin G

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35 Mechanism of action Gram +  peptidoglycane  PBP  lipidic bilayer

36 Mechanism of action Gram -  LPS  lipids  membrane  porines  peptidoglycane  PBP  membrane

37 Pharmacokinetics i.v. benzylpenicilline – PNC G i.m. Pc-PNC, benzatine-PNC extracellular distribution renal excretion of active substance (probenecide) acidostabile incomplete absorption (60%) hydrolytic cleavage, activation, prolonged effect (penamecilline)

38  PNC a poorly lipid soluble and do not cross the blood brain brain barrier  Whey are actively excreted unchanged by the kidney (the dose should be reduced in severe renal failure)  Tubular secretion can be blocked by probenecid to potentiate PNC action

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40 Antimicrobial spectrum gram + cocci (St. pyogenes, St.viridans, St. pneumoniae) staphylococci (  -lactamase-negative) gram + bacilly (B.anthracis, C. diphteriae, L. monocytogenes, C. perfringens  tetani) gram – bacilly (Pasteurella) spirochetes (Treponema) borelia, leptospira (B.anthracis, C. diphteriae, L. monocytogenes, C. perfringens  tetani)

41 SE anaphylaxis Jarisch- Herxheimer sy Hoigné neurotoxicity allergy pregnancy  breast feeding are not contraindicted

42 Penicillinase-Resistant Penicillins (nafcillin, oxacillin, methicillin) Developed to overcome the penicillinase enzyme of S. aureus which inactivated natural penicillins Gram-positive methicillin-susceptible S. aureus Group streptococci viridans streptococci

43 Antistaphylococcal PNC (penicillinase-resistant) meticilline (acidolabile) oxacilline cloxacilline dicloxacilline acidostabile absorption subst.- dependent strong alb. binding good diffusion in parenchym. org. weak BB barrier passage

44 Antistaphylococcal PNC (penicillinase-resistant) Sensitivity: staphylococci (  -lactamase-positive) Resistance: enterococci gram - bacteries

45 Aminopenicillins (ampicillin, amoxicillin) Developed to increase activity against gram-negative aerobes Gram-positive Gram-negative pen-susc S. aureusProteus mirabilis Group streptococciSalmonella, Shigella viridans streptococcisome E. coli Enterococcus sp.  L- H. influenzae Listeria monocytogenes

46 Amino-PNC (penicillinase-non-resistant) ampicilline amoxicilline combination with clavulanic acid acidostabile absorption variable low albumine binding good inflammatory tissue diffusion increased bile concentration mild nephrotoxicity

47 Amino-PNC (penicillinase-non-resistant) Sensitivity: gram + cocci enterococci gram – cocci (N.meningitis & gonorrhoeae) H. influenzae aerobic gram – bacilly (E.coli, Salmonella,Shigella) Resistance: enterobacteriaceae staphylococci (  -lactamase-positive) Pseudomonas B. fragilis

48  -lactamase inhibitors clavulanic acid sulbactam tazobactam irreversible inhibition combination with  - lactame ATB similar kinetics & tissue penetration with no antibacterial activity

49 Penicillin Pearls  Amoxicillin - Largest selling antibiotic Amoxicillin – High dose for otitis media  Augmentin now has several new products  Ampicillin/Sulbactam – Anaerobes!

50 Carboxypenicillins (carbenicillin, ticarcillin) Developed to further increase activity against resistant gram-negative aerobes Gram-positiveGram-negative marginalProteus mirabilis Salmonella, Shigella some E. coli  L- H. influenzae Enterobacter sp. Pseudomonas aeruginosa

51 Carboxy-PNC (antipseudomonas PNC) carbenicilline ticarcilline combination with clavulanic acid Pseudomonas Proteus anaerobs severe infections septicemies meningitis endocarditis urogenital & respiratory infections

52 Ureidopenicillins (piperacillin, azlocillin) Developed to further increase activity against resistant gram-negative aerobes Gram-positiveGram-negative viridans strepProteus mirabilis Group strepSalmonella, Shigella some EnterococcusE. coli  L- H. influenzae Anaerobes Enterobacter sp. Fairly good activityPseudomonas aeruginosa Serratia marcescens some Klebsiella sp.

53 Acylureido-PNC (wider spectrum against gram – bacilly) piperacilline azlocilline combination with tazobactam gram + cocci gram - bacteries Pseudomonas severe infections septicemies meningitis endocarditis abdominal cavity inf. pneumonia

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55 Carbapenems (  -lactams with the widest spectrum) imipenem combination with cilastatin (renal dehydropeptidase inhibitor) good tissue penetration good BB barrier difusion renal excretion-70% of active substance rest as metabolites

56 Carbapenems (  -lactams with the widest spectrum) gram + cocci, staphylococci (even producing penicillinase) Enterococcus faecalis, Listeria monocytogenes gram – aerobs enterobacteries anaerobic bacteries

57 Monobactams aztreonam good tissue & body fluid penetration good BB barrier difusion good bone penetration renal elimination

58 Monobactams Sensitivity: exclusively gram – aerobic bacteries (N.meningitis a gonorrhoeae, H. influenzae) aerobic gram – bacilly (E.coli, Salmonella,Shigella) Pseudomonas aeruginosa Resistance: gram + bacteries anaerobs

59 Cephalosporins

60 Cephalosporins (bactericidal) Acremonium chrysogenum 7- aminocephalosporanic acid cefem

61 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

62 Cephalosporins - I. generation cephazolin cephalotin ----------------------- cephalexin cephadroxil good GI absorption higher levels & activity (parent.) renal elimination of active substance allergies, flebitis, blood cell formation

63 Cephalosporins - I. generation Sensitivity: high effectiveness gram + cocci resistance to  -lactamases of staphylococci Resistance: gram - bacteries weak resistance to  -lactamases of gram - bacteries

64 Cephalosporins - II. generation cefuroxim cephamandol --------------------------- cefuroxim-axetil cephaclor current gram – infections with good sensitivity renal elimination 85-95% (50% in cefuroxim-axetil) risk of bleeding (cephamandol)

65 Cephalosporins - II. generation Sensitivity: high effectiveness gram + cocci good effectiveness some gram - bacteries Resistance: Proteus vulgaris Providencia spp. Serratia spp.

66 Cephalosporins - III. generation cephotaxim cephtrizoxim cephtriaxom cephtazidine ---------------------- cephixim cephtibutem cephetamet- pivoxil rare gram – infections mixed gram – & + gram – meningitis severe pseudomonas infections severe Haemophilus inf. infections renal elimination in dependence on substance pseudomembranous colitis, bleeding, allergy

67 Cephalosporins - III. generation Sensitivity: lower effectiveness: gram + cocci the highest effectiveness gram – bacteries majority of pseudomonas Resistance: Klebsiella pneumoniae (produces cephotaximases) some E.coli, Proteus mirabilis, Salmonella spp. (chromosome encoding  -lactamases)

68 Cephalosporins - IV. generation cefpirom cefepim high effectiveness gram + & gram – bacteries Pseudomonas aer. enterobacter spp. & citrobacter spp. resist. to III. gen.

69 Pearls - Cephalosporins  For gram positive coverage: Cefazolin –When being used for osteomyelits, maximum dosing (150 mg/kg/day) should be used to ensure adequate distribution to affected areas.  For meningitis in pediatrics patients: Neonates-cefotaxime (plus ampicillin) Infants and Children-ceftriaxone Excreted via biliary and urinary tract. May cause biliary sludging and cholecystitis.  For Anaerobic coverage: cefoxitin  For pseudomonas coverage: ceftazidime and cefepime

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72 cephalosporins cephalosporins ethanol ethanol

73 QUESTIONS?

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