What are acylaminopenicillins?
Acylaminopenicillins are broad-spectrum antibiotics belonging to the group of penicillins. A special feature of their molecular structure is the possession of a betalactam ring. In the case of the acylaminopenicillins, however, the betalactam ring is not protected against attack by so-called beta-lactamase, which is formed by certain bacteria. Furthermore, the acylaminopenicillins are also not stable against the influence of acids.
Acylaminopenicillins are used in particular for controlling Gram-negative bacteria of the Pseudomonas or Proteus species. As broad-spectrum antibiotics, however, they can also act against some Gram-positive bacteria.
The main representatives of the group of acylaminopenicillins are the active ingredients azlocillin, mezlocillin, piperacillin or ampicillin. Due to their beta-lactamase and acid instability, the acylaminopenicillins are administered per enterally in the form of venous or muscular infusions.
Pharmacological effect on body and organs
Like all penicillins, acylaminopenicillins also affect the metabolism of bacteria. After their penetration into the bacterial cell, they inhibit the build-up of the bacterial cell wall. Your beta-lactam ring opens in the cytoplasm of the bacterium and binds when opened to the bacterial enzyme D-alanine transpeptidase.
With the help of D-alanine transpeptidase, alanine residues in the cell wall are bound together in the bacterial cell. By blocking this enzyme, this linkage can no longer take place. The bacterium loses the ability to continue dividing and dies.
The bacterial development of antibiotic resistance to the antibiotics of penicillins relies on the ability of the bacterium to synthesize the enzyme beta-lactamase. The beta-lactamase cleaves the beta-lactam ring of the antibiotic before it can interfere with the metabolism. The acylaminopenicillins are also not protected against the attack of beta-lactamase, since the ring is freely accessible in the molecule. Nevertheless, acylaminopenicillins are capable of controlling resistant germs in particular applications.
Since acylaminopenicillins are not acid and beta lactose stable, they must be injected parenterally. So they get immediately via a venous injection into the bloodstream. Also an injection into the muscle is possible. Immediately after administration, the active ingredient then penetrates into the cell of the bacterium and prevents the further development of the bacterial cell wall. The bacterium is not primarily killed. It dies, however, because it can not continue to divide.
Often, acylaminopenicillins are used in combination with beta-lactamase inhibitors to overcome the extensive antibiotic resistance of the bacteria to be controlled. The Betalaktamaseinhibitor inhibits, as the name suggests, the activity of the bacterial enzyme beta-lactamase and can thus enhance the effect of Acylaminopenicilline.
The half-life of Acylaminopenicilline in the body is only about one hour. They are then excreted to 60 percent largely unchanged via the kidneys.
Medical application & use
Acylaminopenicillins are widely used as broad-spectrum antibiotics in the control of infections with the opportunistic bacteria Pseudomonas aeruginosa or enterococci. As a rule, these bacteria are less infectious. However, they can cause severe infections in immunocompromised individuals.
These are usually nosocomial infections (infections with hospital germs). These germs get into the body especially through wounds on the skin or mucous membrane. Patients in intensive care units often cause pneumonia. In addition, they can cause urinary tract disease after urological surgery or the use of permanent catheters, purulent skin infections in wounds, and even sepsis.
The widest range of applications among the acylaminopenicillins and thus also among the penicillins has piperacillin. It works against gram-negative bacteria such as enterobacteria, Pseudomonas aeruginosa and anaerobes as well as against Gram-positive bacteria. Although its action against Gram-positive bacteria is worse than that of some other penicillins, it is considered sufficient in the context of a broad-spectrum effect.
In addition to its use in the control of hospital germs, piperacillin is also used in urogenital infections, gonorrhea, abdominal abscesses, pneumonia, sepsis, bacterial endocarditis, infections in wounds and burns, and bone and joint infections.
Piperacillin is administered both as a single preparation and in combination with beta-lactamase inhibitors. The active ingredient azlocillin, on the other hand, is particularly effective against enterococci and Pseudomonas aeruginosa. It is often used together with cephalosporin for very serious infections caused by unknown pathogens.
Mezlocillin also has a broad spectrum of activity. However, it works less well in Pseudomonas infections than Azlocillin. Although ampicillin is also a broad-spectrum antibiotic, overall it has a lower potency than any other acylaminopenicillin.
Risks & Side Effects
The use of acylaminopenicillins in addition to the many beneficial effects in some cases also risks. Before use, it must always be checked if there is hypersensitivity to penicillins. So it is possible that a cross allergy with other beta-lactam antibiotics is present. Should this be the case, there is a risk of anaphylactic shock when using acylaminopenicillins. Therefore, in existing penicillin hypersensitivity, the use of acylaminopenicillins is absolutely contraindicated.
In rare cases, it can lead to other unwanted side effects. Thus, the occurrence of so-called pseudoallergies with skin redness, rashes and itching is possible.
Very rarely, drug fever, eosinophilia, painless swelling of the skin (Quincke's edema), anemia, inflammation of the veins, inflammation of the kidneys or even permanent platelet proliferation are observed. Overall, there are about the same risks that are observed when using other antibiotics.