Projekt „Zvýšení kvality vzdělávání na UK a jeho relevance pro potřeby trhu práce-ESF Reg. č. CZ.02.2.69/0.0/0.0/16_015/0002362“, je financován z programu OP VVV BETA-LACTAM ANTIBIOTICS Eduard Jirkovský, Přemysl Mladěnka Content BETA-LACTAMS .......................................................................................................................................... 2 PENICILLINS ................................................................................................................................................ 2 CLASSIFICATION OF PENICILLINS ......................................................................................................................... 3 GENERAL ASPECTS OF PENICILLINS’ PHARMACOKINETIC ..................................................................................... 4 NATURAL PENICILLINS ........................................................................................................................................ 4 ANTISTAPHYLOCOCCAL PENICILLINS ................................................................................................................... 6 AMINOPENICILLINS .............................................................................................................................................. 8 ANTIPSEUDOMONAL PENICILLINS ........................................................................................................................ 9 ADVERSE EFFECTS OF ALL PENICILLINS ............................................................................................................. 10 INTERACTION OF PENICILLINS ............................................................................................................................ 11 USE IN PREGNANCY AND BREASTFEEDING ......................................................................................................... 11 CEPHALOSPORINS .................................................................................................................................... 12 CARBAPENEMS ......................................................................................................................................... 16 MONOBACTAMS ........................................................................................................................................ 18 REFERENCES ............................................................................................................................................. 19 Projekt „Zvýšení kvality vzdělávání na UK a jeho relevance pro potřeby trhu práce-ESF Reg. č. CZ.02.2.69/0.0/0.0/16_015/0002362“, je financován z programu OP VVV Beta-lactams • the name of this group of ATBs is based on their common chemical structure (Fig. 1) • all members of this group are bacteriocidal O O S R N R N H H N N O S O H O CO O H 3 penicillines monobactams O S HO R1 N H R2 S R N O N O C O O H C O O H cephalosporins Carbapenems Fig. 1. Chemical structure of β-lactam ATBs. PENICILLINS • the first antibiotics discovered (1928, A. Flemming; isolatated from a mould of the genus Penicillium spp. – originally Penicillium chrysogenum, syn. P. notatum) • naturally occurring penicillins currently used in clinics are penicillin G and penicillin V • currently broadly used against sensitive microbes • all penicillins have short post-antibiotic effect • very good safety profile – they are often drug of choice for many infections • world-wide the most used antibiotic drugs Mechanism of action • primary target – PBP – penicillin binding proteins o i.e. enzymes with transpeptidase activity o the individual microbes differ in structure and affinity to the given compound o mutation in PBP leads to ATB resistance • thus their main effect is to inhibit formation of peptidoglycan chains by preventing formation of the crosslinks due to inhibition of final transpeptidation reaction Projekt „Zvýšení kvality vzdělávání na UK a jeho relevance pro potřeby trhu práce-ESF Reg. č. CZ.02.2.69/0.0/0.0/16_015/0002362“, je financován z programu OP VVV Mechanism of ATB resistence • enzymatic degradation by ß-lactamases (penicillinases, cephalosporinases etc.) • structure modification of penicillin-binding protein (PBP) → lower affinity of PBP to ATB • presence of efflux system or inability of ATB to penetrate to PBP Inhibitiors of ß-lactamase as a tool for limiting the resistance • drugs with no antimicrobial activity • binds to the active site of ß-lactamase and irreversibly inactivate the enzyme (Fig. 2) • effective mainly against ß-lactamases encoded in plasmids • PK parameters are similar to the active ATB which they are used with • clavulanic acid - produced by produkována Streptomyces clavuligerus; currently combined with amoxicillin o certain risk of hepatotoxicity (e.g. transient increase of transaminases, (prolonged) cholestatic hepatitis; mid-to-moderate severity, self-limiting) • sulbactam - combined with ampicillin and cefoperazone • tazobactam – combined with piperacillin and ceftolozane • avibactam – does not contain ß-lactam moiety, approved by FDA in 2015, combined with ceftazidime O O S O O S O N OH O N O O N N COOH COOH COOH N A B C N Fig. 2. Chemical structures of selected inhibitors of ß-lactamases: A: clavulanic acid, B: sulbactam, C: tazobactam Classification of penicillins • natural penicillins – narrow antimicrobial spectrum, easily hydrolyzed by penicillinases • antistaphylococcal penicillins – naturally resistant to penicillinases produced by staphylococci • extended-spectrum penicillins ➢ aminopenicillins – slightly extended antimicrobial spectrum ➢ antipseudomonal penicillins – very extended antimicrobial spectrum, count for carboxypenicillins and ureidopenicillins group Projekt „Zvýšení kvality vzdělávání na UK a jeho relevance pro potřeby trhu práce-ESF Reg. č. CZ.02.2.69/0.0/0.0/16_015/0002362“, je financován z programu OP VVV General aspects of penicillins’ pharmacokinetic • food decrease the absorption of penicillins (except for amoxicillin) • Vd = 0.25 – 0.35 L/kg → do not penetrate into fagocyte cells → they are not effective on strictly intracellular patogens • HEB cross only in case of meningitis, final concentration in the liquor represents ≈ 5 % of plasma concentrations • t1/2 30 – 90 min • main route of elimination is tubular secretion, partially also glomerular filtration • high concentrations is urine • during renal failure is t1/2 prolonged almost to 10 hours • probenecid should be used for decrease of tubular secretion of penicillin O O S S N N H H N O N O O O O COOH A C O O N O H2N S N O O H D N O COOH H H N N B E Fig. 3. Chemical structures of natural penicillins (A-C), procaine (D) and benzathine (E). A: penicillin G, B: penicillin V a C: penamecillin. Differences between penicillin G and V are marked in red. Natural penicillins Classification according to rout of administration (Fig. 3) • for parenteral administration – benzylpenicillin (PEN G) and tis depot formulations • for p.o. administration – phenoxymethylpenicillin (PEN V) and penamecillin Antimicrobial spectrum of natural penicillins • primary to G+ bacteria, from G- bacteria are/were sensitive only G- cocci • G+ cocci ➢ Streptococcus pyogenes – 100 % sensitivity ➢ Streptococcus pneumoniae – “good” sensitivity in Czech Republic ➢ Staphylococcus aureus – 90 % sensitivity Projekt „Zvýšení kvality vzdělávání na UK a jeho relevance pro potřeby trhu práce-ESF Reg. č. CZ.02.2.69/0.0/0.0/16_015/0002362“, je financován z programu OP VVV ➢ Enterococus sp. are resistant • G- cocci ➢ Neisseria meningitis - sensitive ➢ Neisseria gonorrhoeae – occasionally resistant • G+ endospore-forming rods (Bacillus antracis, genus Clostridium) • G+ non-endospore-forming rods (Corynebacterium diphteriae) • spirochaetes (Treponema pallidum is still very sensitive, Borrelia burgdorferi) • some anaerobes • none of penicillins or other β-lactames are not active against mycobacteria and intracellular patogenes (rickettsie, chlamydie, mycoplasmy, legionely), fungi, viruses and protozoans Therapeutic use of natural penicillins • infection caused by “streptococcus” (S. pyogenes) – drug of choice • meningitis caused by “meningococcus” (N. meningitis) and infection caused by S.pneumoniae – high-dose PEN G i.v. is still the first therapeutic choice • syphilis – still very good sensitivity to PEN G, administration along with probenecid is preferable • eradication of carriage state in patients (diphtheria, anthrax, clostridial infections) Non-depot formulation of natural penicillins penicillin G (Fig. 3A, Penicilin G Biotika®) • also known as benzylpenicillin • instable in acidic pH, BAV only 1/3 → only IV administration penicillin V (Fig. 3B, V-penicilin Slovakofarma®, Penbene®, Ospen®) • also known as phenoxymethylpenicillin • stable in acidic pH, cplasma 2-5 times higher than for penicillin G, administered p.o. • Common dosing schedule is 750 mg every 8 hours, event.. 500-750 mg every 6 hours penamecillin (Fig. 3C, withdrawn from market) • acetoxymethylester of penicillin G • dosing interval 8 hours Generally, for the β-lactams ATB, in order to be effectiveness at least on 90 % of the microbial population, the concentration in a specific compartment must be above the minimal inhibition concentration (MIC) for at least 40–50 % of the dosing interval. MIC for streptococci is relatively low, therefore the concentrations of PEN V are above the MIC for about 4 hours after administration of normal dose → dosing interval each 8 hours is sufficient for treatment of streptococci infections. Projekt „Zvýšení kvality