Cov tshuaj tua kab mob Beta lactam (β-lactams) yog hais txog ib pawg loj ntawm cov tshuaj tua kab mob nrog lub nplhaib beta lactam hauv cov qauv tshuaj, suav nrog penicillins thiab cephalosporins uas feem ntau siv hauv kev kho mob, nrog rau cov tshuaj tua kab mob β-lactam tshiab uas tsis zoo xws li cephamycin, sulfur tshuaj chav kawm thiab ib lub nplhaib -lactam.
Xws li cov tshuaj tua kab mob muaj qhov ua tau zoo ntawm cov tshuaj tua kab mob muaj zog, tsis muaj tshuaj lom, nthuav qhia dav thiab ua tau zoo hauv chaw kho mob. Cov txheej txheem tshuaj lom neeg ntawm cov tshuaj no, tshwj xeeb tshaj yog kev hloov pauv ntawm cov saw sab, tau tsim ntau yam tshuaj tua kab mob nrog cov tshuaj tua kab mob sib txawv thiab cov tshuaj tua kab mob thiab ntau yam tshuaj kho mob.
Cov tshuaj tua kab mob Beta lactam yog ntau yam tshuaj tua kab mob, suav nrog penicillin thiab nws cov derivatives, cephalosporins , monoamide rings, carbapenems thiab penicillene enzyme inhibitors thiab lwm yam. Cov tshuaj tua kab mob Beta lactam (β-lactams) yog hais txog cov tshuaj tua kab mob loj uas muaj β-lactam ring hauv cov qauv tshuaj. Yeej txhua yam tshuaj tua kab mob uas suav nrog β-lactam core hauv lawv cov qauv molecular yog cov beta lactam antibiotics.
Cov txheej txheem ntawm kev ua ntawm ntau yam tshuaj tua kab mob β-lactam zoo sib xws, thiab lawv tuaj yeem tiv thaiv cell phab ntsa mucopeptide synthase, uas yog, penicillin khi cov protein, yog li ua rau cuam tshuam rau kev sib txuas ntawm cell phab ntsa mucopeptide, ua rau cov kab mob ntawm phab ntsa ntawm tes tsis zoo, cov kab mob nthuav dav ntawm tes thiab lysis. Ib qho ntxiv, qhov ua rau tuag ntawm cov kab mob yuav tsum suav nrog ua rau muaj kev ua haujlwm autolysin ntawm cov kab mob, thiab cov kab mob hloov pauv yam tsis muaj autolysin qhia ua haujlwm. Cov tsiaj tsis muaj phab ntsa ntawm tes thiab tsis cuam tshuam los ntawm cov tshuaj β-lactam. Yog li, chav kawm ntawm cov tshuaj no tau xaiv cov kab mob tua kab mob ntawm cov kab mob thiab muaj tshuaj lom tsawg rau tus tswv tsev.
Hauv kaum xyoo dhau los, nws tau lees paub tias cov protein tshwj xeeb PBPs ntawm cov kab mob cytoplasmic membrane yog lub hom phiaj ntawm cov tshuaj β-lactam. Tus lej, qhov hnyav ntawm lub cev, thiab kev nkag siab ntawm PBPs ntawm cov xovtooj ntawm tes ntawm ntau cov kab mob sib txawv, tab sis cov kab mob uas muaj cov lej sib thooj muaj hom zoo sib xws thiab lub cev ua haujlwm ntawm PBPs.
Piv txwv li, E. coli muaj 7 hom PBPs. PBP1A thiab PBP1B muaj feem cuam tshuam rau kev ntev ntawm cov kab mob. Penicillin , ampicillin , cephalothin , thiab lwm yam muaj kev sib raug zoo nrog PBP1A thiab PBP1B, uas tuaj yeem tiv thaiv kev loj hlob, kev tsim tawm thiab kev nthuav dav ntawm cov kab mob, thiab cov kab mob yuav yaj thiab tuag. PBP2 muaj feem cuam tshuam rau cov duab ntawm cov raj. Mecillin , clavulanic acid thiab thiomycin (imipenem) tuaj yeem xaiv ua ke nrog lawv los ua kom cov kab mob tsim cov hlwb loj, uas ruaj khov rau osmotic siab, thiab tuaj yeem txuas ntxiv loj hlob rau ntau tiam neeg ua ntej yaj thiab tuag.
Lub luag haujlwm ntawm PBP3 zoo ib yam li PBP1A, tab sis qhov ntau me dua, uas yog cuam tshuam nrog kev tsim septum thiab kev faib cov kab mob. Feem ntau cov tshuaj tua kab mob penicillin lossis cephalosporin feem ntau ua ke nrog PBP1 thiab (lossis) PBP3 los tsim cov filaments thiab spheroids, uas ua rau cov kab mob deform, shrink, maj mam yaj mus rau kev tuag. PBP1, 2, 3 yog qhov tsim nyog rau kev ciaj sia, kev loj hlob thiab kev tsim cov kab mob. PBP4, 5, thiab 6 yog cuam tshuam nrog kev ua haujlwm ntawm carboxypeptidase thiab tsis muaj qhov tseem ceeb rau kev ciaj sia thiab kev tsim cov kab mob. Tom qab cov tshuaj tua kab mob tau ua ke nrog lawv, lawv tsis muaj txiaj ntsig rau cov kab mob.
A. Txhais
Penicillin (penicillin G), tseem hu ua benzyl penicillin, yog ib hom penicillin ntuj uas muaj benzyl sab saw. Nws cov ntsev sodium lossis potassium feem ntau siv. Nws cov hmoov siv lead ua ruaj khov ntawm chav tsev kub thiab yooj yim yaj hauv dej. Nws cov kua dej tsis ruaj khov ntawm chav tsev kub. Thaum nws muab tso rau ntawm 20 ° C rau 24 teev, cov tshuaj tua kab mob txo qis sai, thiab cov khoom puas tsuaj antigenic tuaj yeem tsim tau. Yog li penicillin yuav tsum tau npaj ua kua dej ua ntej siv.
B. Cov nyhuv tua kab mob
Penicillin feem ntau yog ua rau cov kab mob Gram-positive, Gram-negative cocci, Haemophilus, thiab ntau yam kab mob tshwm sim.
Penicillin muaj zog heev rau cov kab mob hemolytic streptococcus, viridis streptococcus, pneumococcus, thiab lwm yam, tab sis cov kab mob enterococcus tsis muaj zog. Staphylococcus aureus uas tsis tsim penicillinase thiab feem ntau Staphylococcus epidermidis muaj zog rau penicillin, tab sis Staphylococcus aureus uas tsim penicillinase tiv taus nws heev.
Gram-positive bacilli, Bacillus diphtheria, Bacillus anthracis, thiab gram-positive anaerobic bacilli xws li Perfringens, Tetanus, Clostridium difficile, Propionibacterium, Eubacterium, Lactobacillus, thiab lwm yam yog txhua yam rhiab rau penicillin. Ntawm cov kab mob gram-negative, meningococci muaj kev nkag siab zoo rau penicillin, thiab tshuaj tiv thaiv tsis tshua muaj. Neisseria gonorrhoeae, uas rhiab rau penicillin, yog qhov nce zuj zus. Bacillus pertussis rhiab rau penicillin. Cov kab mob pathogenic spirochetes xws li Treponema pallidum thiab Leptospira tau nkag siab zoo rau nws.
A. Kev Txhais Lus
Cov tshuaj tua kab mob cephalosporin yog cov tshuaj tua kab mob semi-synthetic ua los ntawm lub nucleus 7-aminocephalosporanic acid (7-ACA) ntawm cephalosporins txuas nrog ntau sab saw. Cov tshuaj tua kab mob no muaj qhov zoo ntawm cov tshuaj tua kab mob dav dav, muaj zog tua kab mob, ruaj khov rau cov kua qaub hauv plab thiab beta lactamase , tsis tshua muaj kev tsis haum tshuaj, (tsuas yog ib feem ntawm kev tsis haum tshuaj nrog penicillin), thiab lwm yam. Raws li nws cov yam ntxwv tua kab mob thiab cov ntawv thov kho mob sib txawv, nws tuaj yeem faib ua plaub tiam neeg ntawm cephalosporins).
B. Cov nyhuv tua kab mob
Cov tshuaj tua kab mob dav dav, feem ntau cov kab mob gram-positive rhiab heev rau nws, tab sis enterococci feem ntau tiv taus nws; feem ntau cov kab mob gram-negative rhiab heev, tshwj tsis yog ob peb cephalosporins, Pseudomonas aeruginosa thiab cov kab mob anaerobic. Cov tshuaj no muaj cov nyhuv tua kab mob synergistic nrog penicillins thiab aminoglycoside tshuaj tua kab mob.
Cephalosporins yog cov tshuaj tua kab mob bactericidal, thiab lawv cov txheej txheem tua kab mob zoo ib yam li penicillins , thiab lawv kuj tuaj yeem khi rau cov protein sib txawv penicillin binding protein (PBPs) ntawm phab ntsa cell.
Cov kab mob muaj ib feem ntawm kev tiv thaiv rau cephalosporins thiab penicillins.
A. Cephamycin
Cephamycin yog ib hom tshuaj tua kab mob beta lactam uas tau los ntawm Streptomyces. Muaj peb hom: A, B, thiab C, hom C yog hom muaj zog tshaj plaws. Nws muaj cov tshuaj tua kab mob dav dav, muaj zog rau cov kab mob gram-negative, ruaj khov rau ntau hom beta lactamases. Cov qauv tshuaj ntawm cephamycin zoo ib yam li cephalosporin, tab sis muaj ib pawg methoxy nyob rau ntawm 7th carbon ntawm cephalosporin nucleus.
Tam sim no, cefoxitin siv dav heev. Nws cov tshuaj tua kab mob thiab cov tshuaj tua kab mob zoo ib yam li cov cephalosporins tiam thib ob. Nws muaj cov txiaj ntsig zoo rau cov kab mob anaerobic suav nrog Bacteroides fragilis. Nws yog qhov tsim nyog rau kev kis kab mob hauv plab, kev kis kab mob poj niam thiab kev kis kab mob sib xyaw nrog cov kab mob anaerobic.
C. Latamoxef
Latamoxef, tseem hu ua moxalactam, muaj cov qauv tshuaj ntawm oxycephalosporin. Nws cov sulfur ntawm qhov chaw 1 yog hloov los ntawm oxygen, thiab carbon ntawm qhov chaw 7 kuj muaj ib pawg methoxy. Nws muaj cov kab mob tua kab mob dav dav thiab muaj cov haujlwm tua kab mob zoo ib yam li cefotaxime. Nws muaj cov nyhuv zoo rau cov kab mob Gram-positive thiab negative thiab cov kab mob anaerobic, tshwj xeeb tshaj yog Bacteroides fragilis. Nws ruaj khov heev rau beta lactamase thiab tswj cov plasma concentration ntev.
C. Cov tshuaj tiv thaiv beta lactamase
D. Cov tshuaj monocyclic beta lactams
Aztreonam yog thawj hom tshuaj tua kab mob monocyclic beta lactam uas tau siv zoo hauv kev kho mob. Nws muaj cov nyhuv tua kab mob zoo rau cov kab mob aerobic gram-negative, nws tiv taus enzyme, tsis muaj tshuaj lom, thiab tsis muaj kev ua xua rau penicillin. Nws siv tau rau cov neeg mob uas ua xua rau penicillin thiab feem ntau siv los hloov aminoglycosides.
E. Carbapenems
Cov tshuaj tua kab mob Carbapenem yog cov tshuaj tua kab mob beta lactam uas tsis zoo li lwm cov tshuaj tua kab mob, nrog rau cov tshuaj tua kab mob dav dav thiab muaj zog tshaj plaws. Vim lawv ruaj khov rau beta lactamase thiab tsis muaj tshuaj lom, lawv tau dhau los ua ib qho ntawm cov tshuaj tua kab mob uas kho cov kab mob loj heev.
Thienamycin cov qauv tshuaj lom neeg yog rau carbapenems, thiab lub nplhaib thiazole muaj cov saw khov, thiab 1-txoj hauj lwm leej faj tau hloov los ntawm cov pa roj carbon. Nws muaj cov tshuaj tua kab mob dav dav nrog cov tshuaj tua kab mob muaj zog thiab muaj tshuaj lom tsawg, tab sis nws muaj kev ruaj ntseg tsis zoo thiab tsis muaj txiaj ntsig zoo. Mipenem (imipenem, imithiamycin) muaj cov yam ntxwv ntawm kev ua haujlwm siab, nthuav dav cov kab mob tua kab mob thiab tiv thaiv enzyme. Nws tau yooj yim tsis ua haujlwm los ntawm dehydropeptidase hauv lub cev. Kev sib xyaw siv yog kev sib xyaw ua ke ntawm cov khoom no thiab peptidase inhibitor cilasTATin, hu ua tienam, uas muaj kev ruaj ntseg zoo thiab yog rau kev tso ntshav tawm.
Cov tshuaj tua kab mob Carbapenem yog ib hom tshuaj tua kab mob beta lactam tshiab uas hloov los ntawm penicillin , uas tau tawm los rau xyoo 1980. Nws cov qauv zoo ib yam li lub nplhaib penicillium ntawm penicillins, tsuas yog tias lub atom sulfur ntawm lub nplhaib thiazole hloov los ntawm carbon, thiab muaj ib qho unsaturated double bond ntawm C2 thiab C3; ntxiv rau, 6-position hydroxyethyl side saw yog reversed conformation.
Cov kev tshawb fawb tau qhia tias nws yog pab pawg tshwj xeeb no uas ua rau cis-kev hloov pauv ntawm hom kev sib xyaw no sib txawv los ntawm qhov niaj zaus penicillene. Nws muaj qhov pom dav heev, muaj zog tiv thaiv kab mob, muaj qib siab tiv taus thiab ruaj khov rau beta lactamase. Tam sim no, Taineng (imipenem thiab cilastatin) thiab meropenem feem ntau siv.
Beta lactam muaj ntau yam kev faib tawm thiab muaj ntau yam kev tua kab mob. Tab sis nws kuj muaj qee qhov kev phiv zoo ib yam li lwm cov tshuaj tua kab mob, yog li cov neeg yuav tsum tau ceev faj tshwj xeeb thaum siv cov tshuaj tua kab mob no.
BALLYA muab kev kuaj betalactam los qhia rau koj seb puas muaj cov beta lactams seem hauv cov khoom noj mis nyuj uas koj noj txhua hnub.
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