Macrolides, Lincomycins Chemotherapeutic drugs Part 3 Macrolides, Lincomycins Wei-wei Hu, PhD huww@zju.edu.cn

Macrolides （大环内酯类）

Macrolides （大环内酯类） First generation: - Erythromycin(红霉素 14) - Medecamycin(麦迪霉素 16) - Spiramycin(螺旋霉素 16) Second generation: - Clarithromycin(克拉霉素 14) - Azithromycin(阿奇霉素 15) - Acetylmedecamycin(乙酰麦迪霉素 16) Third generation: - Telithromycin(替利霉素 14)

General properties of Macrolides 1.Chemistry: contain a macrocyclic lactone ring (usually containing 14 to 16 atoms) to which deoxy sugars are attached. 2.Antimicrobial activity: bactericidal or bacteriostatic, depending on the concentration, high activity in alkaline condition.

General properties of Macrolides 3. Antimicrobial spectrum： G+ organisms: - cocci: streptococcus pyogenes, hemolytic streptococcus and streptococcus pneumoniae (化脓性、溶血性和肺炎链球菌), staphylococcus (produce β-lactamase or MRSA耐甲氧西林的金葡菌) - bacilli: Corynebacterium diphtheria (白喉杆菌), bacillus anthraci (炭疽杆菌) ，clostridium tetani (破伤风杆菌) G- organisms: - cocci: meningococcus (脑膜炎奈瑟菌)， N. gonorrhoeae (淋病奈瑟菌) - bacilli:legionella pneumophila (军团菌), bordertella pertussis(百日咳杆菌), haemophilus influenzae (流感嗜血杆菌)（对大肠埃希菌、变形杆菌无效） Other： - anaerobe （厌氧菌） - mycoplasma pneumoniae （肺炎支原体） - chlamydia （衣原体） - rickettsia （立克次体） - spirochetes （螺旋体）

General properties of Macrolides 4. Mechanism of action (bind to P site): 1. Blocking translocation of peptidyl tRNA from A site to P site (移位, 14) 2. Preventing the peptidyl transfer (转肽, 16C) 3. Inhibiting the formation of functional 70s ribosome 4. Bind to L27 and L22 protein to cause dissociation of peptidyl-tRNA from the ribosome

General properties of macrolides 5. ADME of Macrolides: Absorption: Erythromycin is destroyed by stomach acid and must be administrated with enteric coating. Stearates (硬脂酸) and ester (酯化) are fairly acid-resistant and somewhat better absorbed. Clarithromycin and Azithromycin are stable to acid. Food interferes with absorption (except Clarithromycin). 8

General properties of macrolides 5. ADME of macrolides: (2)Distribution: Erythromycin diffuses readily into most tissues, including prostatic fluid and placenta, BBB impenetrable. (3) Metabolism and Elimination: most metabolized in the liver, excreted in the bile； clarithromycin and its metabolite excreted in urine.

General properties of macrolides 6.Clinical Uses: (1) Mycoplasma（支原体） infections (2) Legionnaire’s disease（军团菌病） (3) Chlamydia infections（衣原体感染） (4) Diphtheria（白喉） (5) Pertussis （百日咳） (6) Streptococcus （链球菌）, staphylococous （金葡菌） infections

General properties of macrolides 7.Adverse response: (1) GI effects: nausea, vomiting, abdominal cramps, etc. (2) Liver toxicity: Cholestatic hepatitis （胆汁淤积性肝炎）. (3) Auditory impairment. (4) Allergic reaction (5) Superinfections

General properties of macrolides 8. Resistance mechanism: (1) modification of the ribosomal binding site (2) production of esterase that hydrolyze macrolides (3) reduced permeability of cell membrane or active efflux (4) Ribosome mutation (base mutation of 23s rRNA or ribosome protein mutation) ***Cross-resistance is complete between erythromycin and the other macrolides.

General properties of macrolides 9. Drug interaction Erythromycin metabolites can inhibit cytochrome P450 enzyme. 正在服用他汀类降血脂药物不能与克拉霉素还是阿奇霉素合用？

Macrolides Erythromycin (红霉素) : chlamydia (支原体) and chlamydial (衣原体) infections, community-acquired pneumonia, penicillin substitute for staphylococcal, streptococcal or pneumococcal infection. Cause obvious GI reactions and liver toxicity. Clarithromycin (克拉霉素) : highest activity, stable to acid, its metabolite has activity. Has PAE. Azithromycin (阿奇霉素, 15): penetrates into most tissues well and released slowly from tissues, permits once daily dosing. High activity against mycoplasma (支原体) and chlamydia(衣原体), G- bacteria. Has PAE. Telithromycin (泰利霉素): 酮内酯类抗生素， good absorption and penetration, high binding to ribosome, low efflux, effective to MLSB resistant bacteria.

Lincomycin & Clindamycin resemble erythromycin in antimicrobial spectrum, mechanism and resistance. bactericidal or bacteriostatic, depending on the concentration, G+ microorganism, G- coccus, anaerobe, chlamydia(衣原体) but not MRSA, mycobacteria pneumoniae (肺炎支原体), aerobic G- bacilli, enterococcus, Clostridium difficile (难辨梭状芽孢杆菌)

Lincomycin & Clindamycin Pharmacokinetics p.o., ~ 90% protein-bound (Clindamycin) penetrate well into most tissue, including bone, but not CSF (except toxoplasmic encephalitis). Metabolized in liver and excreted via bile, and urine

Lincomycin & Clindamycin Clinical Uses severe anaerobic infection aerobic G+ cocci infection (金葡菌骨髓炎) combination with pyrimethamine (乙氨嘧啶) for AIDS-related toxoplasmosis (弓形体病) & with primaquine (伯氨喹) for pneumocystis carinii pneumonia (卡氏肺囊虫肺炎).

Lincomycin & Clindamycin Adverse response: (1)Gastrointestinal effects: nausea, vomiting, abdominal pain, diarrhea antibiotic-associated colitis is caused by toxigenic C difficile (pseudomembranous colitis, 难辨梭状芽孢杆菌引起的伪膜性结肠炎). --Superinfection(二重感染)：an infection following a previous infection, especially when caused by microorganisms that are resistant or have become resistant to the antibiotics used earlier (2)allergic reaction (3)impaired liver function (occasionally)

Vancomycins - Vancomycin - Norvancomycin - Teicoplanin Antibacterial activity (Narrow spectrum) bactericidal for G+ bacteria (especially G+ ococci, including MRSA & MRSE耐甲氧西林表皮葡萄球菌), Clostridium difficile (难辨羧杆菌), Bacterooides fragilis (脆弱拟杆菌, 去甲万古)

Vancomycins Antibacterial Mechanism Inhibiting cell wall synthesis by binding to the D-Ala-D-Ala terminus of nascent peptidoglycan pentapeptide.

Fig. Antibacterial Mechanism of Vancomycins

Vancomycins Resistance - vancomycin-resistant enterococci mechanism: occurred because of the alteration of D-Ala-D-Ala. - vancomycin-resistant staphylococous auteus mechanism: * cell wall thickening * change of the component of cell wall * change of PBP

Vancomycins ADME Oral administration (poorly absorbed，pseudomembranous colitis). Intravenous administration, widely distributed in the body, including CSF when the meninges is inflamed. excreted by glomerular filtration (accumulates when renal function is impaired).

Vancomycins Clinical Uses 1) severe infection caused by MRSA, MRSE, etc. 2) alternative for β-lactams 3) enterococcal (肠球菌) or streptococcus (链球菌) endocarditis(心内膜炎) (strong effect when combined with gentamicin). 4) pseudomembranous colitis ***Overuse should be avoided, in view of limited options for treatment of resistant gram positive infections.

Vancomycins Adverse Reactions 1) Hypersensitive reaction (e.g. red man syndrome) 2) Ototoxicity 3) Nephrotoxicity 4) Gl effects, phlebitis etc.

Chemotherapeutic drugs Part 4 Aminoglycosides & Polymyxins 27

Aminoglycosides 氨基糖苷类抗生素 氨基醇环+氨基糖

Nobel Prize

History Aminoglycosides 1944 Streptomycin (链霉素 based on the research made by Waksman and coworkers within 1939-1943) 1957 kanamycin卡那霉素 1964 gentamicin庆大霉素 1967 tobramycin妥布霉素 Amikacin & netilmicin阿米卡星和奈替米星(semisynthetic)

Aminoglycosides Streptomycin链霉素 Amikacin阿米卡星，丁胺卡那霉素 Neomycin新霉素 Kanamycin卡那霉素 Tobramycin妥布霉素 Gentamicin 庆大霉素 Micronomicin 小诺米星 Sisomicin 西索米星 Astromicin 阿司米星 Amikacin阿米卡星，丁胺卡那霉素 Netilmicin奈替米星 B kanamycin卡那霉素B Arbekacin阿贝卡星 Dibekacin地贝卡星 Etilmicin依替米星 Isepamicin异帕米星 两大类：天然产生的包括：链霉菌产生的链霉素，卡那霉素，妥布霉素，新霉素等；小单孢菌产生的：庆大霉素，西索米星，小诺米星，阿司米星等 半合成品：阿米卡星，奈替米星，异帕米星等

Aminoglycosides 1. Antimicrobial activity: i) rapidly bactericidal to resting bacterium ii) broad-spectrum：G- bacilli，G+ organisms (MRSA - netilmicin), TB, less active to G- cocci, and ineffective for anaerobic strains. iii) clinical applications: for the treatment of aerobic G- bacilli infections and tuberculosis iv) unabsorbable in GI tract v) more active in alkaline environment G-杆菌：铜绿假单胞菌，大肠埃希菌，变形杆菌，肠杆菌，志贺菌，枸橼酸菌

Aminoglycosides 1. Antimicrobial activity: vi) concentration-dependent activity vii) the duration of post antibiotic effect (PAE) is concentration- dependent. viii) first exposure effect (FEE) Blood Concentration MIC Peak Concentration Time (h) Bacterial growth is inhibited long after concentration below the MIC

Aminoglycosides General properties 2. Mechanisms of action: act as ionic- sorbent, act directly on permeability of the cell membrane of bacterium. Produce hydroxyl radical

Aminoglycosides 2.Mechanism of action (3) Bind to 30S subunit of ribosome to inhibit the whole process of protein synthesis i) Interfering with the initiation complex of peptide formation (30S or 70S). ii) Inducing misreading of mRNA, which causes the incorporation of incorrect amino acid into peptide, resulting nonfunctional or toxic protein. iii) Blocking the binding of terminator and the release of peptide. iv) disrupt the normal cycle of ribosome, make the ribosome exhausted.

Aminoglycosides 3. Mechanism of Resistance i) The microorganism produces a modified enzyme that inactivate the aminoglycoside by adenylation, acetylation or phosphorylation. ii) The receptor protein on the 30S ribosomal subunit may be deleted or altered as a result of mutation. iii) Impaired entry of aminoglycoside into the cell. iv) Increased efflux

Diagrammatic representation of transfer and transfer reduction of aminoglycoside across the bacterial cell wall. If it is modified by acetylation, adenylation, or phosphorylation, the drug will not bind to ribosomes and will leave the bacterial cell.

Aminoglycosides 4. ADME i) Absorption: not absorbed by oral, but rapidly absorbed after i.m. ii) Distribution: minimal binding to plasma protein; high concentrations in secretions and body fluids; unable to cross cell membrane and BBB, able to cross the placenta. Tissue level is low except in the cortex of kidney and endolymph and perilymph of inner ear. iii) Metabolism and Elimination: excreted mainly by glomerular filtration. Accumulation occurs in renal failure with dose-related toxic effects.

Aminoglycosides 5. Clinical Uses mostly used against infection induced by aerobic G- bacilli . G- bacilli induced severe infection, such as sepsis(败血症), pneumonia and meningitis, almost always used in combination with b-lactam antibiotics (广谱半合成青霉素、三代头孢) and fluoroquinolones. G+ cocci severe infection: combined with vancomycin or β-lactamase- resistant penicillins TB (streptomycin) and atypical mycobacteria分枝杆菌 (Amikacin)

Aminoglycosides 7. Adverse reactions i) Ototoxicity （耳毒性） Caused by progressive destruction of vestibular and cochlear sensory cells (hearing loss irreversible!!). Cochlear toxicity: tinnitus （耳鸣） and high frequency hearing loss Kanamycin>Amikacin>Sisomicin>Gentamicin>Tobramycin Vestibular toxicity: vertigo, ataxia and loss of balance Kanamycin>Streptomycin>Sisomicin>Gentamicin>Tobramycin

Aminoglycosides 7. Adverse reactions ii) Nephrotoxicity consists of damage to the kidney tubules but reversible Neomycin> Kanamycin>Gentamicin>Streptomycin or Tobramycin>Amikacin

Aminoglycosides 7. Adverse reactions iii) Neuromuscular blockade (paralysis) generally occurred after intra-pleural or intra-peritoneal instillation of large doses of aminoglycosides Treatment: Calcium salt or inhibitor of cholinesterase (neostigmine) . Neomycin>Streptomycin>Amikacin or Kanamycin> Gentamicin>Tobramycin

Aminoglycosides 7. Adverse reactions iv) Allergic reaction skin rashes, fever, angioneurotic edema, anaphylactic shock, etc.

Streptomycin 1. ADME i) Absorption: im ii) Distribution: mainly at extracellular fluid, can cross the BBB when meninges is inflamed. iii) Excretion: 90% from kidney 2.Clinical uses i) plague鼠疫(耶尔森菌) and tularemia兔热病(土拉菌病): combination with an oral tetracycline. ii) tuberculosis: as a first-line agent iii) bacterial endocarditis: (enterococcal, viridans streptococcal, etc.), streptomycin and penicillin produce a synergistic bactericidal effect.

Streptomycin 3. Adverse reactions i) Allergic reaction skin rashes, fever, anaphylactic shock ii) Ototoxicity: disturbance of vestibular function, deafness of newborn iii) Neuromuscular blockade (paralysis)：avoided in Myasthenia Gravis, avoided combining with anesthetics, scoline iv) Nephrotoxicity

Gentamicin 1. ADME Gentamicin can accumulate in cortex of the kidney . 2.Clinical use : i) serious G- bacillary infections (沙雷菌属首选，sepsis, pneumonia, etc.). ii) infection induced by enterococcus, viridans streptococcus, staphylococcus etc. (in combination with other antibiotics, e.g. b-lactams) iii) prevent the infection induced by operation (e.g., gastrointestinal operation) iv) local application

Tobramycin 1. Features 抗肺炎杆菌、肠杆菌、变形杆菌、绿脓杆菌较gentamicin强 Only effective to staphylococcus in G+ cocci 2. Adverse reactions Ototoxicity less toxic to cochlear and vestibular Nephrotoxicity less renal tubular damage

Amikacin 1.Antibacterial activity: the broadest in the group. - effective against G- bacilli and staphylococcus aureus - ineffective to other G+ cocci - tolerance to modifying enzyme of enteric G- bacilli and pseudomonas 2.Clinical uses : - treatment of G- bacillary infections which are resistant to gentamicin and tobramycin. - most strains resistant to Amikacin found also resistant to other aminoglycosides. - combination with b-lactams, produce a synergistic bactericidal effect.

Netilmicin 1. Broad spectrum, especially strong effect against aerobic G- bacilli. Effective against MRSA and strains resistant to other aminoglycosides. 2. Tolerant to many aminoglycosides- inactivating enzymes. 3. Less toxic Like other aminoglycosides, netimicin also produce Ototoxicity and Nephrotoxicity, but some studies suggested that netimicin may be the less toxic.

Polymyxins 多粘菌素 1.Notice: because of the extreme toxicity, they are now rarely used. 2.Antibacterial activity: narrow spectrum (G- bacilli), slow active, bactericidal. Not active to G+ organisms, G- coccus, Bacterooides fragilis(脆弱杆菌）, proteusbacillus vulgaris（变形杆菌）, serratia plymuthica（沙雷菌属）

Polymyxins 3. Mechanism of action: they interact with phospholipids (are surface-active) and penetrate into and disrupt the structure of cell membranes. 4. Clinical uses: substitute of β-lactams and aminoglycosides, to treat infection of pseudomonas aeruginosa (铜绿假单胞菌属) and other G- bacilli, local application. 卫生部在2010年印发了《产NDM－1泛耐药肠杆菌科细菌感染诊疗指南（试行版）》: 轻、中度感染：敏感药物单用即可，如氨基糖苷类、喹诺酮类、磷霉素等，也可以联合用药，如氨基糖苷类联合环丙沙星、环丙沙星联合磷霉素等。无效患者可以选用替加环素、多粘菌素。

Mechanism of Polymyxins action

Polymyxins 6. Adverse reaction: (1) Nephrotoxicity (22%) (2) Neurotoxicity (3) Allergic reaction (4) other reactions

Tetracyclines & Chloramphenicol Part 5 Tetracyclines & Chloramphenicol 四环素和氯霉素

Part A Tetracyclines

Tetracyclines Divided into: Crude products (Naturally occurring) - Chlortetracycline (金霉素) - Oxytetracycline(土霉素) - Demeclocycline(地美环素) Semisynthetic derivatives - Doxycycline(多西环素) - Minocycline(米诺环素) - Meclocycline(甲氯环素) - Lymecycline(赖甲环素) - Methacycline(美他环素) - Rolitetracycline(吡甲四环素) - tigecycline (替加环素 ) (glycylcyline, 2005 approved)

Tetracyclines 1. Antimicrobial activity: (1) Bacteriostatic (2) Bactericidal (at high concentration) (3) Minocycline>Doxycycline>Tetracycline

Tetracyclines 2. Antimicrobial spectrum: (1)Broad spectrum: active against a wide range of aerobic and anaerobic gram-positive and gram-negative bacteria (对肠球菌、变形杆菌、绿脓杆菌不敏感). (2)Effective against Rickettsia (立克次体), spirochetes (螺旋体), Pneumoniae (支原体), Chlamydia (衣原体), and Plasmodium (疟原虫). (3) Ineffective against fungi (eg. candida albicans白色念珠菌), virus.

Tetracyclines 3. Mechanism of action: (1) Enter bacteria by passive diffusion through porins or active transport by an energy-dependent system. (2) Inhibit protein synthesis in susceptible microorganisms (bind to A site and block combination of tRNA with 30S subunit). (3) Increase the permeability of the cell membrane

Tetracyclines, Chloramphenicol, Macrolides

Tetracyclines 4. Resistance Mechanism: (1) Decreased intracellular accumulation due to increased efflux by a active transport protein pump. (2) Ribosome protection that interfere with the tetracycline binding to the ribosome. (3) Enzyme inactivation of tetracycline.

Tetracyclines 5. ADME of Tetracyclines: (1) Absorption largely differ from each other after oral administration (doxycycline and minocycline 95-100%). Absorption are impaired by food (except doxycycline and minocycline). (2) Distributed widely to tissue and body fluid except for CSF (minocycline exclusive). (3) Excreted mainly in bile and urine.

Tetracyclines 5. ADME of Tetracyclines: (4) Able to penetrate the placenta and are also excreted in the milk. (5) As a result of chelation with calcium, tetracyclines are bound to- and damage- growing bones and teeth.

Tetracyclines 6.Clinical Uses (1)Rickettsial (立克次体) infections. (2)Mycoplasma (支原体) infections: M. pneumonia and M.urealyticum (肺炎支原体/溶脲支原体). (3)Chlamydia(衣原体) infection：Chlamydia psittaci, pneumonia, rachomatis (鹦鹉热/肺炎/沙眼衣原体). (4)Leptospira (螺旋体) infection：Borrelia burgdorferi, recurrentis, treponema pallidum (伯氏疏/回归热/梅毒螺旋体) infection. (5)Bacterial infection: Calymmatobacterium granulomatis, Vibrio cholerae, brucellosis (肉芽肿鞘杆菌/霍乱弧菌/布鲁菌) infection.

Tetracyclines 7. Adverse reactions (1)Gastrointestinal effects. (2)Superinfections. (3)Deposition of the drugs in growing teeth and bones. (4)Hepatic toxicity and renal toxicity. (5)Photosensitivity(光敏反应). (6)Vestibular toxicity. 假脑瘤：头痛蓝视为特征的非恶性颅内压增高

Tetracyclines 8. Drug interaction antacids containing aluminum, calcium, or magnesium, and iron-containing preparations Impaire the absorption of tetracyclines anticoagulant therapy Because tetracyclines have been shown to depress plasma prothrombin activity bacteriostatic drugs interfere with the bactericidal action of penicillin

Part B Chloramphenicol (氯霉素) Chemical structure p 1246 p776pharm

Chloramphenicol 1. Antimicrobial activity: (1) Possesses a wide antimicrobial spectrum aerobic and anaerobic, G- > G+, rickettsia (立克次体), spirochetes (螺旋体), mycobacteria (支原体) but not chlamydia (衣原体), virus, fungi (2) Primarily bacteriostatic, bactericidal to certain species.

Chloramphenicol 2. Mechanism of action Inhibit protein synthesis in susceptible bacteria, and to a lesser extent in mammalian cell (mitochondrial ribosomes resemble bacterial ribosomes, both are 70 S). Acts primarily by binding reversibly to the 50 S ribosomal subunit (near the site of action of macrolides and clindamycin).

Tetracyclines, Chloramphenicol, Macrolides 71

Chloramphenicol 2. Mechanism of Resistance Usually caused by a plasmid-encoded acetyltransferaes that inactivates the drugs. (2) The permeability of bacterial cell membrane is changed.

Chloramphenicol 3. ADME: (1) p.o. or i.v. (2) Distributed widely to tissue and body fluid including CSF, placenta, milk (inhibit the bacteria in cells). (3) Metabolized by liver and excreted by kidney.

Chloramphenicol 4.Clinical uses with caution (1) Bacterial meningitis (替代-内酰胺类) or intracerebral abscess(脑脓肿). (2) Typhoid fever(伤寒,喹诺酮和三代头孢首选) . (3) Eye bacterial infection. (4) Anaerobic infection. (5) Rickettsial disease and brucellosis (布鲁菌病), etc.

Chloramphenicol 5. Adverse reactions (1)Hematological Toxicity: by dose-related toxic effect on bone marrow: anemia(贫血), together with leukopenia(白细胞减少症) or thrombocytopenia (血小板减少症) by idiosyncratic response: aplastic anemia(再生障碍性贫血), leading in many cases to fatal pancytopenia(全血细胞减少症).

Chloramphenicol 5. Adverse reactions (2) Toxicity for newborn infants: - Gray baby syndrome (灰婴综合征). (3) Other reactions: - GI reactions - hypersensitivity reaction - neuritis (sight impairment) - CNS side effects

Chloramphenicol 6. Drugs interactions - Inhibiting hepatic P450 enzyme, thus prolonging the half-life time of drugs that metabolized by this system, e.g. warfarin, phenytoin, tolbutamide, etc. - Rifampicin, phenytoin and pentobarbital accelerate its metabolism. - If have to combined with penicillin, chloramphenicol should be dosed later. - Antagonistic to lincomycins and macrolides.