Beta-lactam antibiotics

Examples of Beta-lactam antibiotics in the following topics:

• Beta-Lactam Antibiotics: Penicillins and Cephalosporins

  • The β-lactam ring is part of the core structure of several antibiotic families.
  • A β-lactam (beta-lactam) ring, is a four-membered lactam .
  • The β-lactam ring is part of the core structure of several antibiotic families, the principal ones being the penicillins, cephalosporins, carbapenems, and monobactams, which are, therefore, also called β-lactam antibiotics.
  • Bacteria do, however, contain within their populations, in smaller quantities, bacteria that are resistant against β-lactam antibiotics.
  • Together with cephamycins, they constitute a subgroup of β-lactam antibiotics called cephems.

• Inhibiting Cell Wall Synthesis

  • β-Lactam (beta-lactam) and glycopeptide antibiotics work by inhibiting or interfering with cell wall synthesis of the target bacteria.
  • The first class of antimicrobial drugs that interfere with cell wall synthesis are the β-Lactam antibiotics (beta-lactam antibiotics), consisting of all antibiotic agents that contains a β-lactam nucleus in their molecular structures.
  • PBPs vary in their affinity for binding penicillin or other β-lactam antibiotics.
  • Bacteria often develop resistance to β-lactam antibiotics by synthesizing a β-lactamase, an enzyme that attacks the β-lactam ring.
  • Describe the two types of antimicrobial drugs that inhibit cell wall synthesis: beta-lactam and glycopeptide antibiotics

• Antibiotic Classifications

  • Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics slow their growth or reproduction.
  • Antibiotics can be divided into two classes based on their mechanism of action.
  • Bactericidal antibiotics kill bacteria; bacteriostatic antibiotics inhibit their growth or reproduction.
  • Examples include the Beta-lactam antibiotics (penicillin derivatives (penams) ), cephalosporins (cephems), monobactams, and carbapenems) and vancomycin.
  • Penicillin and most other β-lactam antibiotics act by inhibiting penicillin-binding proteins, which normally catalyze cross-linking of bacterial cell walls.

• Relative Resistance of Microbes

  • In addition, they are naturally resistant to a number of antibiotics that disrupt cell-wall biosynthesis, such as penicillin.
  • Most mycobacteria are susceptible to the antibiotics clarithromycin and rifamycin, but antibiotic-resistant strains have emerged.
  • Gram-negative bacteria have high natural resistance to some antibiotics.
  • Examples include Pseudomonas spp. which are naturally resistant to penicillin and the majority of related beta-lactam antibiotics.
  • Their resistance to most antibiotics is attributed to efflux pumps, which pump out some antibiotics before the antibiotics are able to act.

• Microorganisms in the Hospital

  • Many types are difficult to attack with antibiotics, and antibiotic resistance is spreading to Gram-negative bacteria that can infect people outside the hospital.
  • MRSA is any strain of Staphylococcus aureus that has developed resistance to beta-lactam antibiotics, which include the penicillins (methicillin, dicloxacillin, nafcillin, oxacillin, etc.) and the cephalosporins.
  • Strains unable to resist these antibiotics are classified as methicillin-sensitive Staphylococcus aureus, or MSSA.
  • The development of such resistance does not cause the organism to be more intrinsically virulent than strains of Staphylococcus aureus that have no antibiotic resistance, but resistance does make MRSA infection more difficult to treat with standard types of antibiotics, and thus more dangerous.

• Allergic Responses to Drugs

  • The most reported drug allergy is to Beta-lactam antibiotics, of which penicillin is the most well-known type, affecting 1-5% of people who take penicillin.

• Naturally Occurring Antimicrobial Drugs: Antibiotics

  • There are mainly two classes of antimicrobial drugs: those obtained from natural sources (i.e. beta-lactam) antibiotic (such as penicillins, cephalosporins) or protein synthesis inhibitors (such as aminoglycosides, macrolides, tetracyclines, chloramphenicol, polypeptides); and synthetic agents.
  • A β-lactam (beta-lactam) ring is a four-membered lactam.
  • A lactam is a cyclic amide.
  • The simplest β-lactam possible is 2-azetidinone.
  • Rifamycin inhibits prokaryotic DNA transcription into mRNA by inhibiting DNA-dependent RNA polymerase by binding its beta-subunit.

• Antibiotics from Prokaryotes

  • Even though penicillin drugs, antibiotics produced by molds, were the first antibiotics successfully used to treat many serious infections, most of the naturally produced antibiotics are synthesized by bacteria.
  • These were the first antibiotics to be manufactured commercially.
  • Clavulanic acid (from S. clavuligerus) is a drug used in combination with some antibiotics (like amoxicillin) to block and/or weaken some bacterial-resistance mechanisms by irreversible beta-lactamase inhibition.
  • Other bacterial species produce antibiotics as well.
  • Explain the role of Streptomyces and other prokaryotes in antibiotic production

• Bacterial Skin Diseases

  • Today, topical or oral antibiotics are usually prescribed.
  • Most cases of erysipelas are due to Streptococcus pyogenes (also known as beta-hemolytic group A streptococci), although non-group A streptococci can also be the causative agent.
  • Beta-hemolytic, non-group A streptococci include Streptococcus agalactiae, also known as group B strep or GBS.
  • Depending on the severity, treatment involves either oral or intravenous antibiotics, using penicillins, clindamycin, or erythromycin.
  • The mainstay of therapy remains treatment with appropriate antibiotics Recovery periods last from 48 hours to six months.

• Pharyngitis

  • Bacterial or fungal causes are often amenable to antibiotics and anti-fungal treatments, respectively.
  • Streptococcal pharyngitis, more commonly known as strep throat, is caused by group A beta-hemolytic streptococcus (GAS).
  • For step throat, antibiotics are useful in preventing complications and expediting recovery.
  • Antibiotics are effective in the early stages, but recovery is generally slow.