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rdf:type | |
lifeskim:mentions | |
pubmed:dateCreated |
1986-10-16
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pubmed:abstractText |
The essential nucleus of beta-lactam antibiotics is the four-membered ring, which can exist fused to form bicyclic ring structures or with moieties alone affixed to the four atoms. Penicillins, penems, carbapenems, and clavams have asymmetric centers at C-5 and C-6; cephalosporins and oxacephems have asymmetric centers at C-6 and C-7. Penicillins, cephalosporins, and monobactams require a beta-acylamino group for antimicrobial activity. Cephalosporins can undergo modification at C-3 and C-7 in both the alpha and beta position. Sulfur can be replaced with oxygen to achieve a more reactive nucleus. The most useful 7-beta-acylamino groups have been a 2-aminothiazolyl and an iminomethoxy or carboxypropyl group. Substitutions on the 7-alpha position increase beta-lactamase stability but decrease activity against staphylococci and Streptococcus pneumoniae. C-3 substitutions, particularly pyridinium groups, increase activity against Pseudomonas aeruginosa and Staphylococcus aureus. Carbapenems possess 6-alkyl substitutions in a trans configuration and inhibit aerobic, anaerobic gram-positive, and gram-negative bacteria. Monobactams are activated by sulfonic, phosphoric, or carboxyl groups, and their properties are related to the C-3-acyl side chain and their beta-lactamase stability to the C-4 grouping. beta-Lactamase inhibitors acylated by beta-lactamases can be penicillanic acid derivatives or clavulanates.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Anti-Bacterial Agents,
http://linkedlifedata.com/resource/pubmed/chemical/Cephalosporins,
http://linkedlifedata.com/resource/pubmed/chemical/Monobactams,
http://linkedlifedata.com/resource/pubmed/chemical/Penicillins,
http://linkedlifedata.com/resource/pubmed/chemical/beta-Lactamases
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pubmed:status |
MEDLINE
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pubmed:issn |
0162-0886
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:volume |
8 Suppl 3
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
S237-59
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:3529320-Anti-Bacterial Agents,
pubmed-meshheading:3529320-Bacteria,
pubmed-meshheading:3529320-Cephalosporins,
pubmed-meshheading:3529320-Chemical Phenomena,
pubmed-meshheading:3529320-Chemistry,
pubmed-meshheading:3529320-Monobactams,
pubmed-meshheading:3529320-Penicillins,
pubmed-meshheading:3529320-Structure-Activity Relationship,
pubmed-meshheading:3529320-beta-Lactamases
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pubmed:articleTitle |
beta-Lactam antibiotics: structural relationships affecting in vitro activity and pharmacologic properties.
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pubmed:publicationType |
Journal Article,
Review
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