Chair of Medical biology, Microbiology, Virology, and Immunology Doctrine about antibiotics. Antimicrobial chemotherapy. Clinical use of antibiotics Lecturer Prof. S.I. Klymnyuk

Lectures schedule 1. History of antibiotics discovery. 2. Classification of antibiotics. 3. Examination of bacterial susceptibility to antibiotics. Complication of antibioticotherapy.

- Diarrheal diseases - 4 billions cases, Malaria - 500 mln, acute infection of respiratory tract - 395 mln, sexual transmitted diseases - 330 mln, measles - 42 mln, whooping cough - 40 mln tuberculosis – 1,9 bln of infected persons, 9 mln of new cases of diseases AIDS – 50 mln cases, 6 mln people died SARS, hemorrhagic fever

This idea has been called the "magic bullet" concept The earliest evidence of successful chemotherapy is from ancient Peru, where the Indians used bark from the cinchona tree to treat malaria. Other substances were used in ancient China, and we now know that many of the poultices used by primitive peoples contained antibacterial and antifungal substances. Modern chemotherapy has been dated to the work of Paul Ehrlich in Germany, who sought systematically to discover effective agents to treat trypanosomiasis and syphilis. He discovered p-rosaniline, which has antitrypanosomal effects, and arsphenamine, which is effective against syphilis. Ehrlich postulated that it would be possible to find chemicals that were selectively toxic for parasites but not toxic to humans. This idea has been called the "magic bullet" concept

It had little success until the 1930s, when Gerhard Domagk discovered the protective effects of prontosil, the forerunner of sulfonamide. Ironically, penicillin G was discovered fortuitously in 1929 by Fleming, who did not initially appreciate the magnitude of his discovery. In 1944 Waksman isolated streptomycin and subsequently found agents such as chloramphenicol, tetracyclines, and erythromycin in soil samples. A. Fleming

In 1939 Florey and colleagues at Oxford University again isolated penicillin G. Florey E. Chainy

S. Waksman

Antibiotics are chemical substances produced by microorganisms (such as bacteria, fungi, actinomyces) or other organisms which suppress the growth of other microorganisms and eventually destroy them. Some antibiotics have been produced by chemical synthesis or semi-synthetically from natural substances.

Microbial antagonism is the basis of modern use of antibiotics L. Pasteur

It means: anti – against, bios - life The term “antibiotics” proposed in 1942 S. Waksman It means: anti – against, bios - life

Peculiarities of antibiotics - high level of biological activity high election specificity

Activity of antibiotics is evaluated in International Unit

Classification of antibiotics according to 1. Antibiotics from fungi: their origin 1.  Antibiotics from fungi: Penicillins (Penicillium notatum, P. chryzogenum), Cephalosporins (Cephalosporium salmosynnematum), Griseofulvinum (P. griseofulvum, P. patulum, P. nigricans), Fusidin (Fusidium coccineum),

Antibiotics from Actinomyces: а) Aminoglicosides: Streptomycin (Streptomyces griseus), neomycin (S. fradiae), kanamycin (S. kanamyseticus), tobramycin (S. tenebrarius), gentamycin (Micromonospora purpurea), sisomicin (Micromonospora inyoensis); б) Tetracyclines: chlortetracycline (S. aureofaciens), oxytetracycline (S. rimosus); в) Chloramphenicol (S. venezuelae); г) Macrolides: oleandomycin, (S. antibioticus), erythromycin (S. erythreus), д) Linkomycin (S. lincolniensis); е) Rifampicin (S. mediterranei); є) Polyenes: nystatin (S. noursei), levorin (S. levorys Krass), amphotericin B (S. nodosus); ж) Inhibitors of beta-lactamases: klavulanic acid (S. clavuligerus), Carbapenem (S. olivaceus), thienamycin (S. cattleya).

3. Antibiotics from bacteria: а) Bacillus: polymyxin (B 3.  Antibiotics from bacteria: а) Bacillus: polymyxin (B. polymyxa), licheniformin (B. licheniformis), gramicidin С (B. brevis), subtilin (B. subtilis); б) Pseudomonas: piocianin (P. aeruginosa), sorbistin (P. sorbistini), в) other bacteria: monobactams (Chromobacterium violaceum), nisin (Streptococcus lactis), prodigiosin (Serratia marcescens), coliformin (E. coli), streptosin, diplococcin (штами Streptococcus), azomycin, nocardamin (nocardia)

Antibiotics from plants а) Chorellin (Chlorella vulgaris); в) Arenarin (Helichrysum arenarium); c) Gordecin (barley); d) Chinin (cinchona tree); e) Alicin (garlic, Allium sativum); f) Raphanin (radish, Raphanus sativum); g) Phaseolin (haricot bean, Phaseolus vulgaris).

5.  Antibiotics from animal tissues: а) interferons (spleen, macrophages, tissue cells), б) lysozyme (most body fluid, salive, eggs); в) erythrin (red cells, liver); г) ecmolin (fish)

Classification of antibiotics according to the spectrum of biological action 1. Antibacterial: А. Narrow spectrum of action which are active against gram-positive bacteria: а) natural Penicillins; b) semi-synthetic Penicillins (methicillin, oxacillin); c) Cephalosporins d) Lincomycin; е) Macrolodes. Б. Broad spectrum of action а) semi-synthetic Penicillins (Ampicillin, Amoxicillin); b) Cephalocporins of ІІ-IV generation; c) Tetracyclines; d) Chloramphenocol; e) Aminoglycosides; f) Polymixins; g) Fluoride quinolones

2. Antifungal (amphotericin). 3. Antiviral (amantadin, vidarabin). 4. Antiprotozoal (emethin, хінін, фумагілін). 5. Antineoplastic (bleomycin, mitomycin C, actinomycines).

Antimicrobial agents may be either bactericidal, killing the target bacterium or fungus, or bacteriostatic, inhibiting its growth. Bactericidal agents are more effective, but bacteriostatic agents can be extremely beneficial since they permit the normal defenses of the host to destroy the microorganisms.

Antibacterial drugs Beta-lactam antibiotics Penicillins Beta-lactamase inhibitors C. Cephalosporins D. Thienamycins (carbapenems) E. Monobactams (monocyclic beta-lactams) F. Some pharmacokinetic aspects of beta-lactam antibiotics G. Adverse reactions of beta-lactam antibiotics H. Interactions of beta-lactam antibiotics

I. Aminoglycosides and polymyxins A. Aminoglycosides B. Polymyxins J. Macrolides, lincomycin and clindamycin A. Macrolides B. Lincomycin and clindamycin K. Tetracyclines and chloramphenicol A. Tetracyclines B. Chloramphenicol L. Glycopeptides and fusidanes A. Vancomycin B. Fusidic acid

L. Rifamycins M. Fosfomycin O. Sulfonamides and trimethoprim P. The new quinolones Q. Nitroimidazoles R. Antifungal agents S. Antiviral agents

Basic structures of ß-lactam antibiotics

Vancomycin interrupts cell wall synthesis by forming a complex with the C-terminal D-alanine residues of peptidoglycan precursors

Diagrammatic representation of inhibition sites of protein biosynthesis by various antibiotics that bind to the 30S and 50S ribosomes

Examination of susceptibility of bacteria to antibiotics serial dilutions: - in a liquid medium - in a solid medium Disc diffusion method Rapid methods

Demands to nutrient media - to be standard and provide optimal conditions for microbial growth; · do not have inhibitors of bacterial growth and a lot of stimulators; · do not have substances, which inhibit antibiotic activity

Disc diffusion method

Serial dilution in liquid medium

Serial dilution in solid medium

Rapid methods examination of changes of microbial enzymes activity under the influence of antibiotics; examination of color of redox-indicators; cytological evaluation of morphological changes; automatic

Automatic metod of examination of bacterial susceptibility

General principles 1. The first question to ask before prescribing an antibiotic is whether its use is really necessary. There is no point in prescribing it if, for instance, the disease is not due to an infection (fever does not always indicate the presence of an infection), or if the infection is due to agents such as viruses, which do not respond to antibiotics. All therapy is a calculated risk in which the probable benefits must outweigh the draw­backs, and antibiotics are no exception to this rule. To use them when they are not indicated and when the "probable benefits" are non-existent means exposing the patient to the risk of adverse reactions, or worse.

2. Patients with similar infections react differently 2. Patients with similar infections react differently. This may be due to previous contact with the same pathogen or to the individual immune response. The presence of hepatic or renal disease may necessitate changes in the dosage or the choice of antibiotic. Knowledge of any past adverse reactions to antibiotics is also essential. 3. The doctor must be familiar with the typical response of infections to proper antibiotic treatment. Acute infection with group A streptococci or pneumococci responds rapidly (usually within 48 hours) to penicillin G, while the temperature curve in typhoid fever treated with chloramphenicol may not show any change for four or five days.

4. The doctor must know which bacteria are commonly found in which situations, for instance Pseudomonas in extensive burns (sepsis is frequent and often fatal) and in the expectoration of children with cystic fibrosis, or Streptococcus pneumoniae and Haemophilus influenzae in chronic bronchitis of the adult.

5. Ideally, treatment with antibiotics should not be instituted before samples for sensitivity testing have been collected. Such tests can be dispensed with, however, when the causative organism is known and its response to the antibiotic is predictable. But the sensitivity of, for instance, many gram-negative strains can change, even during treatment, making an alternative treatment necessary. In addition, the clinical results may be at odds with the findings of the sensitivity tests. Even a severe infection may show a satisfactory clinical response despite apparent lack of sensitivity.

Failure of antibiotic therapy Antibiotic treatment is considered a failure if no response is seen within three days. Failure may be due to various causes: 1. Wrong diagnosis (a viral infection does not respond to antibiotics). 2. Wrong choice of antibiotic. 3. Wrong dosage (wrongly dosed by doctor or poor patient compliance). 4. Development of resistance during therapy (as sometimes occurs in tuberculosis and infections due to gram-negative pathogens). 5. Superinfection by resistant bacteria. 6. Accumulation of pus necessitating surgical drainage (buttock abscess). 7. Underlying disease (lymphoma, neoplasia) of which the infection is only an intercurrent complication. 8. Drug fever.

Secondary action of antibiotics І. Allergic reactions - dangerous for life (anaphylactic shock, angioneurotic oedema of larynx) - non-dangerous for life (skin itching, urticaria, rash, rhinitis, glossitis, conjunctivitis, photodermatoses (tetracyclines) ІІ. Toxic reactions - dangerous for life (agranulocytosis, aplastic anemia, endotoxic shock) - non-dangerous (neuritis of N. vestibularis and N. auricularis - aminoglycosides; periferal neuritis, vomiting, nausea, diarrhea, hepatotoxic and nephrotoxic effects, embriotoxic effect (pigmentation of the teeth)

- non-dangerous for life (local candidiases) ІІІ. Dysbacteriosis - dangerous for life (generalized candidiases sepsis, staphylococcal enterocolitis, secondary pneumonia, which cause gram-negative bacteria) - non-dangerous for life (local candidiases)

Mechanisms of Resistance

Types of resistance Natural resistance Acquired resistanse - primary - secondary

R-Plasmids Resistance transfer factors, or RTFs

Transposons Staphylococci, Enterobacteria – transposon Tn551 (erythromycin), Tn552 (penicillin), Tn554 (erythromycin, spectinomycin). They can integrate with R-plasmids and phages

Mechanism to Reduce Bacterial Resistance. Proper selection of new antibiotics will be a major force in slowing the development of antimicrobial resistance. Proper hygiene practices will reduce plasmid transfer and the establishment of multiple drug-resistant bacteria in the hospital and will delay the appearance of such species in the community. There are a number of mechanisms to prevent bacterial resistance. The health care provider must be continually alert to the appearance of antibiotic resistance within the hospital and community.