1、ANTI-BACTERIAL CompoundsGermicide / antiseptic on skin & disinfectant on thingsExternal use most are oxidants: Cl2, O3, I2, NaOCl, H2O2, KMnO4, Chloramine-T,Chloramine-T Phenol(s) Triclosan Methyl salicylatePhenols: generally toxic through skin but 1.5 % is tolerableegs. Lysol (= p-cresol), TCP (= t
2、richlorophenol), phenol (carbolic acid, R=H), Triclosan Listerine contains menthol, thymol, methyl salicylate and eucalyptol,Quaternary Ammonium Compounds - Mouthwash - R4N+ X-,Cetyl pyridinium bromide Domiphen bromide (Life, Safeway brands, etc.),Cetrimonium bromide is (CH3)3N+(CH2)15CH3 Br- = cetr
3、imide,Chlorhexidine for gingivitis,INTERNAL USE:,Bacteria divided into Gram +ve and Gram -ve groups:Crystal violet stain turns both purple but only Gram +ve reamin so after I2 treatment and an acetone-alcohol-water wash Gram +ve have thick walls with no outer membrane and trap stain egs. Streptococc
4、us, Staphylococcus, PneumonococcusGame ve have thin walls with inner and outer membranes and do NOT retain the stain egs. Meningitis, Salmonella, E. Coli, Pseudomonas,TB (tuberculosis, consumption) (Mycobacterium tuberculosis) destroys lung tissue, still kills ca. 1-2M / yWHO estimates 1/3 pop of ea
5、rth carries TB bacteriumTB vaccine essentially wiped out TB in the West but ca. 424K/y drug resistant cases (ca. 30K/y are VERY drug resistant)UVic case February 2009,rifampicin and isoniazid are most common treatment but procedure is long and many cut it short: as a result 1.2% of cases are resista
6、nt,Serious concerns that TB could reappear in West:No new drugs for 40 years but 30 now under studyA new Johnson &Johnson drug (R207910) is under trials that inhibits ATP synthaseBayer is in trials with moxifloxacinNovartis is in trials with a nitroimidazole,THE SULFA DRUGS: effective against most G
7、ram +ve, some Gram veFOLIC ACID PABA p-aminobenzoic acid,We eat folic acid; bacteria make it from PABA: we can fool them using sulfanilamide so they die of vitamin deficiency,a sulfanilamide Sulfapyridine Sulfadiazine Sulfathiazole,sulfamethoxazole common in Canada,PENICILLINS (Narrow spectrum antib
8、iotics)History: Original mould: penicillin notatum (pencil shapes) discovered by Fleming while working on staph bacteria, left cover plate off and noticed bacteria did not grow near mould,Flory (Oxford, 1940) found way to extract penicillin out of mould, tried it on London policeman with blood poiso
9、ning from shaving cut.Wartime: needed to make much more, (used bed pans in Oxford to grow mould) so in June 1941 took production to USA (15,000 gallon vessels)Mould now: penicillin chrysogenum found on a cantaloupe in Peoria, Illinois in 1943 gave better yields and is used to make Pen-G,Penicillins:
10、 general formula includes the b-lactam ring,Pen-V Ampicillin Amoxicillin CloxacillinYou can make those other than Pen-G by feeding the mould the appropriate acid, RCOOH,Pen-G,Pen-G has to be injected: 600-2400 mg/day IV in 3-4 dosesUseful against most GRAM +ve plus pneumonia, meningitis,gonorrhea, g
11、angrene, bone infectionsOthers can be taken orally:Pen-V: 300mg per 8h, first oral oneAmoxicillin: most common, 250-500 mg per 8hAmpicillin: best for urinary tractCloxacillin: approved for some resistant bacteriaMany people are allergic to Penicillins (especially G) can lead to death!,HOW PENICILLIN
12、S WORK:b-lactam ring binds to a transpeptidase enzyme responsible for forming the cross links in the peptidoglycan layer (bacterial cell walls):as the cell grows it needs to constantly break these layers: If it cant expand, the cell bursts and diesBUT some bacteria have Penicillinase, an enzyme that
13、 cleaves the b-lactam ring and allows normal wall formation: resistant,Five Penicillins are more resistant to Penicillinase: mainly reserved for Staph infections (egs. Nafcillin and Methicillin),CEPHALOSPORINS: from mould found in sewage (Sardinia 1950s),a cephalosporin Cefachlor (Ceclor) Cefepime (
14、Maxipime)250 mg/8h, 2g/day max 1 g/12h for 10 days,Very popular (2B$/y) more effective than penicillins against Gram -ve typesCPS lists 16 in use all start with Cef-Not affected by penicillinase but a cephalosporinase has now emerged,WIDE SPECTRUM ANTIBIOTICS: MYCINS and TETRACYCLINESStreptomycin (f
15、rom soil) in 1947 stops cell division, shuts down protein/RNA synthesis Too toxic for use, then last resort for TBAlso from soil: the tetracyclines:,Chlorotetracycline (Aureomycin)X=Cl, Z=OHtetra-cyclo = 4 rings Tetracycline (Terramycin, (A,B,C,D) Ambramycin,.)X=H, Z=OH,More common ones now:,Doxycyc
16、line (Vibramycin) X=H, Z=OH, no OH in ring B Minocycline (Klinomycin) X=NMe2, Z=H, no OH or Me in ring B Demeclocycline (Declomycin) X=Cl, Z=H, no Me in ring B,Doses: 250-600 mg/6h,They inhibit protein synthesis by binding to the ribosome, Kill most bacteria = broad spectrum including intestinal bac
17、teria, so side effect is DIARRHEAEat pro-biotic yogurt when on this (and shortly after stopping)!,Was used against Legionnaires Disease (Chicago 1976)Ca salts, antacids bind to them: avoid milk and antacidsSide effects: browning of teeth (acne treatment for teens)photosensitive skinreduced effective
18、ness of birth control pillsMostly excreted unchanged high levels can be found in sewage!,Aside on Legionnaires disease: hundreds staying at one hotel fell ill (34 died) during the 1976 American Legion Convention in Chicago - discovered that the pneumonia-like illness was caused by a previously unkno
19、wn bacterium, now known as Legionella pneumophillia. Turns out the bacteria proliferates in warm, stagnant water, in this case in the hotel air conditioning system. Subsequent outbreaks have occurred in 1999 (Netherlands flower show, 34 died), 2001 (Spain, hospital cooling tower, 6 died) and 2002 (U
20、K, Art Center cooling tower, 7 died),AMINOSUGARS (AMINOGLYCOSIDES)ERYTHROMYCIN CLINDAMYCIN (Dalacin),Very widely used More toxic allergic reactions rare usually only for more serious infectionscross placenta and go in to breast milkDose: 1 g/day in 2-4 doses; up to 4 g/day in more serious cases,VANC
21、OMYCIN,Last resort for many staph types: interferes with wall synthesisVRE = Vancomycin resistant enterococci (opportunistic gut infection) - in Canadian hospitals (see chart at right),DAPTOMYCIN,used against VRE and methicillin resistant staph (MRSA)* (stops synthesis of cell membranes),* flesh eat
22、ing disease 30% mortality,QUINOLONES - CIPROQuinolones are synthetic, made first in 1987They block bacterial DNA replication by stopping the re-coiling of new strands, make KNOTS insteadCIPROFLOXACIN: most active broad spectrum antibiotic available (Anthrax scare) Sales 2B$/yespecially useful for lu
23、ng infections, bones, urinary tract (oral or IV),Related: Norfloxacin (Noroxin) Et in place of cyclopropyl,Some newer ones:,Levofloxacin Trovafloxacin GemifloxacinLEVAQUIN TROVAN wide use for TBOthers: moxifloxacin; gatifloxacin; ofloxacin Trovan (2 x 200mg/day): In Canada about 360,000 pneumonia ca
24、ses per year, still 7000 deaths,Some strains of staph which are Vancomyin and Methicillin resistant are now resistant to Cipro,Need to keep making newer classes:,2-Pyridones and Oxazolidinones,Linezolid (ZYVOXAM) Antagonize enzymes: Bind the bacterial ribosome, shuts down protein synthesis,NEWEST AP
25、PROACH EFFLUX PUMP BLOCKERS Some resistant strains pump antibiotic out of the cell: these block that pump action MICROCIDE have found a peptide that stops pseudomonas effluxing fluoroquinolones = drug ca. 8x more effective,2005: FDA granted fast track status to intravenous iclaprim for the treatment
26、 of complicated skin and skin structure infections (cSSSI) resistant staph,ANTI-FUNGALS,Tolnaftate, Tinactin, Pitrex Fungistop, Triactin topical only, inhibits steroid biosynthesis,Griseofulvin (Fulvicin, Grisovin, Grisactin) hair and nail infections orally for ringworm,made by mould penicillin gris
27、eofulvin: disrupts the microtubulesNot if pregnant: teratogen Not with alcohol: tachycardia,NYSTATIN (mycostatin) especially for yeast (candida) infections (mouth, throat, vagina, underarms),Method of action: binds to ergosterol, the main component of the fungal cell membrane. If present in sufficie
28、nt concentrations, it forms a pore in the membrane that leads to K+ leakage and death of the fungus. (mammals do not have ergosterol-based cell membranes),MONISTAT (miconazole)Vaginal yeast infections: inhibits biosynthesis of triglycerides (fats), phospholipids, steroids and damages the fungus cell
29、 wall Used topically as 2-3% cream,OTHER ANTIFUNGALS Terbinafine LAMISIL Ketoconazole NIZORAL cream, shampoo, tablets Fluconazole DIFLUCAN capsules Itraconazole SPORONOX capsules, solution Clotrimazole CANESTAN VAGINAL & TOPICAL cream or inserts Oxiconazole OXIZOLE cream, lotion Chlorphenesin MYCIL creamSelenium sulfide is often used in shampoos, sold as VERSEL (lotion),
