beta-lactam antibiotics

Beta-lactam antibiotics are a class of antibiotics that have a common component in the form of a ring structure of beta-lactam and is commonly used to treat infections of bacteria  . There are approximately ± 56 kinds of beta-lactam antibotik have antivitas antimicrobials in the beta-laktamnya cincing and if the ring is cut by microorganisms , there will be resistance to these antibiotics.

 

Types

Penicillin

Based on the spectrum antimikrobialnya activity, penicillin is divided into 4 groups, namely penicillin early (earlier), penicillin spektruk wide, penicillin anti-staphylococcal and anti-pseudomonal penicillin (expanded spectrum) . Early penicillin is actively able to fight bacteria that are sensitive, such as the class of Streptococcus beta-hemolytic , Streptococcus alpha-hemolytic combined with an aminoglycoside ),pneumococcus , meningococcus , and group Clostridium other than C. difficile .Examples of previous penicillin is penicillin G and penicillin V . Broad-spectrum penicillins have the ability to fight bacterial enteric and more easily absorbed by a gram negative bacteria but is still susceptible to the degradation of beta-lactamase, such as ampicillin, amoxicillin, mesilinam, bacampicillin , etc . anti-staphylococcal penicillinwas developed in the 1950's to cope with S. aureus that produce beta-lactamase and has the advantage of resistance to beta-lactamase activity . Examples of this group are methicillin and cloxacillin. Anti-pseudomonal penicillin made ​​to overcome the bacterial infection gram negative bacilli, including Pseudomonas aeruginosa , an example of this group are penicillin carbenicillin, ticarcillin, Azlocillin, and piperacillin

cephalosporin

Antibioik divided into 3-generation cephalosporins, the first is cephalothin and cephaloridine that was not widely used . The second generation (among others: cefuroxime, cefaclor, cefadroxil, cefoxitin, etc..) Is used widely to overcome the infection and some of the weight of which have activity against anaerobic bacteria . The third generation of cephalosporins (among them: ceftazidime, cefotetan, latamoxef, cefotetan, etc..) Made in the 1980's to address the systemic infection due to severe bacterial gram-negative -bacillus .

 

carbapenem

There is only one class of carbapenem antibiotic agents that are used for clinical care, ie who has the ability to imipenem antibacterialexcellent against gram-negative bacilli (including P. aeruginosa , Staphylococcus , and Bacteroides ) . The use of imipenem must be combined with specific enzyme inhibitors to protect it from degragasi enzymes of the liver in the body.

Monobactam

This group has the structure of beta-lactam ring is not bound to the second ring in the molecule . One of this class of antibiotics commonly used is the aztreonam is active against many gram-negative bacteria , including P. Aeruginosa.

Mechanism of action

Beta-lactamase antibiotics work by killing bacteria menginhibisi cell wall synthesis . In the process of formation of the cell wall , a reaction catalyzed by the enzyme transpeptidasi transpeptidase and produce crosslinking between the two chains of peptides - glucan. Enzyme transpeptidase located on the membrane cytoplasmic bacteria are also able to bind to beta-lactam antibiotics, causing this enzyme is capable of catalyzing the reaction transpeptidasi although the cell wall still continue to be formed. The cell walls that form has no crosslinking and peptidoglycan formed is not perfect so more weak and easily degraded. In normal conditions, the difference in osmotic pressure within cells and gram-negative bacteria in the environment will make the occurrence of cell lysis. In addition, the complex protein transpeptidase and beta-lactam antibiotics will stimulate autolisin compounds that can mendigesti the bacterial cell wall. Thus, the loss of bacterial cell wall and having lysis will die.

Mechanism of resistance

Some bacteria are known to have resistance to beta-lactam antibiotics, one of which is the class of S. aureus , methicillin resistant ( methicillin resistant Staphylococcus aureus / MRSA). Bacteria that are resistant to beta-lactam antibiotics has three mechanisms of resistance, the destruction of the beta-lactamase antibiotics, reduce the penetration of antibiotic to bind to the proteintranspepidase, and lower binding affinity between the protein binding with antibiotic compounds. Some bacteria such asHaemophilus influenzae , type Staphylococcus , and most of the rod-shaped enteric bacteria have enzymes beta-lactamases that break down beta-lactam ring in antibiotics and make it inactive. In detail, the mechanisms that occur beginning with the termination of the CN bonds in beta-lactam ring and lead to an antibiotic can not bind to protein transpeptdase resulting in loss of ability to menginhibisi formation of bacterial cell wall. Some studies suggest that in addition is found naturally in bacteria gram positive and negative, the gene encoding the enzyme beta-lactamase was also found on the plasmid and the transposon so that it can be transferred between species of bacteria. This causes the resistance ability of the beta-lactam antibiotics would be able to spread rapidly. Diffusion of beta-lactam antibiotics into bacterial cells occurs through the mediation of transmembrane proteins called porine and diffusion capacity is influenced by size, charge, and the nature of the hydrophilic of an antibiotic.

Overcoming resistance to beta-lactam antibiotics

To overcome the degradation of beta-lactam cincing, some beta-lactam antibiotics combined with the compound inhibitors of the enzyme beta-lactamase as clavulanat acid, tazobactam , orsulbactam. One of the beta-lactam antibiotic-resistant beta-lactamase is augmentin, Amoxycillin and clavulanic acid combination. Augmentin has been proven to successfully overcome the bacterial infection of the urinary tract and skin. Yng clavulanic acid is produced from the fermentation of Streptomyces clavuligerus has the ability to inhibit the active enzyme , causing beta-lactamase enzyme becomes inactive. Some types of beta-lactam antibiotics (eg, nafcillin ) also have properties resistant to beta-lactamase because it has a side chain with a specific location.