Beta-Lactam Antibiotics and Their Classification

Beta-lactam antibiotics inhibit cell wall synthesis.

They lead to bacterial lysis by damaging cell wall integrity.

Beta-lactam antibiotics lack activity against atypical organisms like Mycoplasma pneumoniae and Chlamydophila pneumoniae.

<p>PBPs facilitate the cross-linking of peptidoglycans in the bacterial cell wall.</p> Signup and view all the answers

<p>Their effectiveness depends on the duration of exposure above the minimum inhibitory concentration (MIC).</p> Signup and view all the answers

<p>Inhibition leads to weakened cell walls, swelling, and eventual bacterial lysis.</p> Signup and view all the answers

<p>Beta-lactam antibiotics may cause cross hypersensitivity reactions among various drugs in this class.</p> Signup and view all the answers

<p>The activation of autolysing enzymes such as Murein Hydrolase and Autolysins enhances lethality.</p> Signup and view all the answers

<p>Itching, rashes, fever, angioedema, and rarely anaphylactic shock.</p> Signup and view all the answers

<p>The metabolic opening of the β-lactam ring creates a reactive penicilloyl group that binds with tissue proteins, forming an antigenic determinant.</p> Signup and view all the answers

<p>A maximum of 10%.</p> Signup and view all the answers

<p>Diarrhoea due to alteration in normal intestinal flora.</p> Signup and view all the answers

<p>Benzylpenicillin (Penicillin G).</p> Signup and view all the answers

<p>Convulsions.</p> Signup and view all the answers

<p>Aminopenicillins and antipseudomonal penicillins.</p> Signup and view all the answers

<p>Neutropenia.</p> Signup and view all the answers

<p>The combination enhances activity against β-lactamase producing strains of bacteria.</p> Signup and view all the answers

<p>Azlocillin and piperacillin are examples of ureidopenicillins.</p> Signup and view all the answers

<p>Pseudomonas aeruginosa is specifically mentioned as being more active against these penicillins.</p> Signup and view all the answers

<p>Inactivation of the antibiotic by beta-lactamase is one mechanism of resistance.</p> Signup and view all the answers

<p>Carbapenems are highly resistant to hydrolysis by penicillinases and cephalosporinases.</p> Signup and view all the answers

<p>They inactivate penicillins preferentially, leading to resistance against these antibiotics.</p> Signup and view all the answers

<p>Ampicillin is a narrow-spectrum penicillin primarily used against certain gram-positive bacteria.</p> Signup and view all the answers

<p>Escherichia coli and Klebsiella spp. are targets of treatment with these combinations.</p> Signup and view all the answers

<p>Cross-linking is essential for septum formation during cell division; its inhibition leads to filamentation, preventing cells from separating.</p> Signup and view all the answers

<p>Penicillin is more effective against Gram-positive bacteria due to their thick peptidoglycan layer, which is easily accessible to beta-lactam antibiotics.</p> Signup and view all the answers

<p>The outer membrane of Gram-negative bacteria contains lipopolysaccharides and narrow porin channels, which act as a barrier to the permeability of antibiotics.</p> Signup and view all the answers

<p>Hydrophilic penicillins diffuse through the porin channels of Gram-negative bacteria, allowing them to exert their antimicrobial effects.</p> Signup and view all the answers

<p>Peptidoglycan is unique to bacteria and provides structural integrity to their cell walls, making it a prime target for antibiotics that interfere with its synthesis.</p> Signup and view all the answers

<p>Natural resistance in Gram-negative bacteria occurs due to deeply located target enzymes and penicillin-binding proteins (PBPs) shielded by a lipoprotein barrier.</p> Signup and view all the answers

<p>Acquired resistance can occur through the production of beta-lactamase, alteration of porin channels, or modifications of PBPs that lower their affinity for penicillin.</p> Signup and view all the answers

<p>Common organisms producing beta-lactamase include Staphylococcus, Bacillus subtilis, Gonococci, E. coli, Enterococci, and Haemophilus influenzae.</p> Signup and view all the answers

<p>It is indicated for minor infections such as tonsillitis.</p> Signup and view all the answers

<p>BPG provides prolonged drug levels for effective secondary prophylaxis against rheumatic fever.</p> Signup and view all the answers

<p>They are indicated for infections caused by beta-lactamase-producing staphylococci.</p> Signup and view all the answers

<p>Aminopenicillins have an amino side group that enhances their ability to penetrate gram-negative bacteria.</p> Signup and view all the answers

<p>They are both vulnerable to destruction by beta-lactamases.</p> Signup and view all the answers

<p>The recommended dosage is 2.4 million units IM once a week for 1–3 weeks.</p> Signup and view all the answers

<p>Food can reduce the absorption rate of isoxazolyl penicillins, making them less effective.</p> Signup and view all the answers

<p>The addition of a hydroxyl group (−OH) increases its acid stability.</p> Signup and view all the answers

A group of antibiotics that all share a common chemical structure containing a beta-lactam ring.

The mechanism by which a drug exerts its effect on a target.

The rigid outer layer of a bacterial cell, essential for maintaining its shape and protecting it from osmotic pressure.

Specialized enzymes within bacteria responsible for cross-linking peptidoglycans, forming a strong, rigid cell wall.

The process of connecting peptidoglycan chains together to create a strong, stable cell wall.

Beta-lactam antibiotics inhibit transpeptidases, preventing the cross-linking of peptidoglycans and weakening the bacterial cell wall.

The rupture or breakdown of a bacterial cell, caused by damage to its cell wall and osmotic imbalance.

Beta-lactam antibiotics are most effective during the active multiplication phase of bacteria, when their cell walls are being actively built and repaired.

The process of cross-linking, where peptidoglycan chains bind together, is essential for forming the rigid cell wall in bacteria. This process is disrupted by antibiotics like penicillin.

Gram-positive bacteria have thicker layers of peptidoglycans and teichoic acid. This structure makes their cell walls more accessible to antibiotics like penicillin.

Gram-negative bacteria have two membranes. The outer membrane contains lipopolysaccharides and porin channels. These channels control the permeability of antibiotics, making it harder for them to reach the peptidoglycans.

Penicillin is more effective against gram-positive bacteria due to their accessible cell wall structure. The thick peptidoglycan layer allows penicillin to bind and disrupt cross-linking.

Gram-negative bacteria have a less accessible cell wall due to the outer membrane with porin channels, which act as a barrier to antibiotics.

Penicillinase (β-Lactamase) is an enzyme produced by some bacteria that breaks down penicillin, rendering the antibiotic ineffective.

Some bacteria have adapted by modifying their penicillin-binding proteins (PBPs), making them less sensitive to penicillin.

Loss or alteration of porin channels in gram-negative bacteria can hinder the entry of antibiotics, leading to resistance.

A serious, sometimes fatal, reaction to penicillin that involves the immune system. It's characterized by symptoms like itching, rashes, fever, and swelling, and can progress to life-threatening anaphylactic shock.

The ability of some bacteria, primarily gram-negative bacteria, to actively pump out antibiotics, making them resistant to the medication.

A group of antibiotics known for their effectiveness against a wide range of bacterial infections.

A group of antibiotics known for their effectiveness against a limited range of bacterial infections.

One of the main risks associated with penicillin use. This reaction can range from mild skin reactions to life-threatening anaphylactic shock.

A type of penicillin effective against a wide range of bacteria, including gram-negative bacteria, and is often used to treat pneumonia and urinary tract infections.

A type of penicillin particularly effective against gram-positive bacteria, particularly those that produce beta-lactamase, an enzyme that can break down penicillin.

A type of penicillin specifically effective against common bacterial infections, including strep throat, pneumonia, and meningitis.

A penicillin derivative with an added amino group, which increases its ability to pass through the outer membrane of gram-negative bacteria.

An example of an aminopenicillin with improved oral absorption due to an added hydroxyl group.

Also known as penicillinase-resistant penicillins, these penicillins are effective against bacteria that produce beta-lactamase enzymes.

A type of antistaphylococcal penicillin that is commonly used to treat infections caused by staphylococci.

An example of an isoxazolyl penicillin that is used to treat mild to moderate localized staphylococcal infections.

The oral form of penicillin, which is indicated for minor infections due to its limited bioavailability and short duration of action.

A type of penicillin administered through injection that provides prolonged, but low levels of penicillin in the body.

Penicillins that have a broader spectrum of activity against gram-negative bacteria than aminopenicillins, but are still more effective against gram-positive bacteria.

Combinations of penicillins with β-lactamase inhibitors, such as clavulanate or sulbactam, are used to overcome resistance to penicillin by bacteria that produce β-lactamases.

Penicillins with a side group that allows them to penetrate gram-negative bacteria more effectively than aminopenicillins.

The process by which bacteria disable beta-lactam antibiotics by breaking the beta-lactam ring, rendering the antibiotic inactive.

Bacterial resistance mechanism where the target site of the antibiotic, PBPs, is modified so the antibiotic cannot bind.

The process of bacterial resistance where the antibiotic cannot reach its target site within the bacteria due to altered permeability.

A mechanism of bacterial resistance where the antibiotic is actively pumped out of the bacteria, preventing it from reaching its target.

The most common mechanism of bacterial resistance to beta-lactam antibiotics, where bacteria produce enzymes that break down the antibiotics.