The first antimicrobial was discovered in the early twentieth century. In 1929, Professor of London University Alexander Fleming engaged in a detailed study of the properties of green mold and noted its special antibacterial properties. And in 1940, the pure culture of this substance was derived, which became the basis of the first antibiotic. So there was all known penicillin, saving lives for many people for almost 80 years.
Further, the development of the science of antimicrobial agents was on the increase. There were more and more effective antibiotics that had a disastrous effect on microbes, inhibiting their growth and reproduction.
Working in this direction, microbiologists have discovered that some of the antimicrobial substances isolated behave in a special way. They show antibacterial action against several species of bacteria.
Preparations based on such substances of natural or synthetic origin, so beloved by doctors of various specializations, have been called broad-spectrum antibiotics (AHSD) and have received no less widespread in clinical practice.
And yet, despite all the benefits of the above drugs, they have one significant drawback. Their activity against a variety of bacteria extends not only to pathogenic microorganisms, but also to those that are vital for the human body, forming its microflora. So the active intake of oral antibiotics can ruin the beneficial intestinal microflora, causing disruption to its functioning, and the use of vaginal antibiotics - disrupt the acid balance of the vagina, provoking the development of fungal infections. In addition, the toxic effect of antibiotics of the first generation did not allow them to be used for the treatment of patients with liver and kidney pathologies, for the treatment of infectious diseases in childhood, during pregnancy and in some other situations, and a large number of side effects led to the treatment of one problems provoked the development of another.
In this regard, the question arose of finding solutions to the problem of how to make antibiotic treatment not only effective, but also safe. Developments began to lead in this direction, which facilitated the entry of a new product to the pharmaceutical products market - effective antibiotics of a broad spectrum of action of a new generation with fewer contraindications and side effects.
Groups of antibiotics of a new generation and development of antibiotic therapy
Among a large number of antimicrobial drugs (AMP), several groups of drugs with a difference in chemical structure can be distinguished:
- Beta-lactams, which are divided into the following classes:
- Carbapenems with increased resistance in beta-lactamases produced by certain bacteria
- Macrolides (the least toxic drugs of natural origin)
- Antibiotics of tetracycline
- Aminoglycosides, especially active against gram-negative anaerobes, causing respiratory diseases
- Lincosamides, resistant to the effects of gastric juice
- Antibiotics of levomycetin
- Glycopeptide preparations
- Polymyxins with a narrow spectrum of bacterial activity
- Quinolones, and in particular fluoroquinolones, which have a wide spectrum of action.
In addition to the above-mentioned groups, there are several more classes of narrowly directed drugs, as well as antibiotics that can not be attributed to a particular group. Also, several new groups of drugs have appeared recently, although they have a predominantly narrow spectrum of action.
Some groups and drugs are familiar to us for a long time, others appeared later, and some are not even known to a large consumer
Antibiotics 1 and 2 generations can not be called ineffective. They are applied to this day. However, not only the person develops, but also the microbes within it, acquiring resistance to frequently used drugs. The third generation antibiotic, in addition to acquiring a wide spectrum of action, was also called upon to defeat such a phenomenon as antibiotic resistance, which became especially relevant recently, and some antibiotics of the 2nd generation did not always successfully cope with it.
Antibiotics of the 4th generation, in addition to a wide spectrum of action, have other advantages. Thus, penicillins of 4 generations differ not only in their activity against gram-positive and gram-negative microflora, but, having a combined composition, become active also in the case of Pseudomonas aeruginosa, which is the causative agent of a large number of bacterial infections affecting various human organs and systems.
Macrolides of the 4th generation are also combined preparations, where as an active ingredient is the antibiotic tetracycline, which expands the field of activity of the drugs.
Particular attention should be paid to cephalosporins 4 generations, the spectrum of which is rightly called ultra-wide. These drugs are considered to be the strongest and most widely used in clinical practice, as they are effective against a strain of bacteria resistant to previous-generation AMS.
And yet, even these new cephalosporins are not without shortcomings, since they can cause multiple side effects. Struggle against this moment is conducted and to this day, therefore from all known cephalosporins of 4 generations (and their order of 10 varieties) in mass production only preparations on the basis of cefpirom and cefipim are admitted.
The only drug of the 4th generation from the aminoglycoside group is able to fight with pathogenic microorganisms such as cytobacter, aeromonas, and nocardia, which are beyond the control of earlier generations. It is also effective against Pseudomonas aeruginosa.
Broad-spectrum antibiotics of the 5th generation are predominantly ureido and piperazinopenicillins, as well as the only permitted drug from the cephalosporin group.
Penicillins of the 5th generation are considered effective against Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa. But their disadvantage is the lack of resistance to beta-lactamases.
The active component of the approved cephalosporins of the 5th generation is ceftobiprol, which has a rapid absorption and good metabolism. It is used to control strains of streptococci and staphylococci, resistant to beta-lactams of early generations, as well as with various anaerobic pathogens. The peculiarity of the antibiotic is that under its action the bacteria are not capable of mutating, which means that they do not develop antibiotic resistance.
Antibiotics based on ceftaroline are also highly effective, but they lack a protective mechanism against beta-lactamases produced by enterobacteria.
A new drug based on the combination of ceftobiprol and tazobactam has also been developed, which makes it more resistant to the effects of various types of beta-lactamases.
Antibiotics of the 6th generation of the penicillin series are also not devoid of a wide spectrum of action, but they are most active in relation to gram-negative bacteria, including those with which the frequently prescribed penicillins of 3 generations based on amoxicillin can not cope.
These antibiotics are resistant to most bacteria that produce beta-lactamases, but are not deprived of the usual side effects for penicillins.
Carbapenems and fluoroquinolones are classified as relatively new types of antimicrobial agents. Carbapenems are highly effective, resistant to most beta-lactamase drugs, but they can not withstand New Delhi metallo-beta-lactamase. Some carbapenems are not effective against fungi.
Fluoroquinolones are synthetic drugs with pronounced antimicrobial activity, which are close in action to antibiotics. They are effective against most bacteria, including mycobacteria tuberculosis, some varieties of pneumococci, Pseudomonas aeruginosa, etc. However, for anaerobic bacteria their effectiveness is extremely low.