Antibiotic and antimicrobial – differences

It is common to confuse antimicrobial and antibacterial medicines. Today we will tell you what their difference is, and also determine when what medicine is prescribed.

Antibacterial drugs – against bacteria

An “antibiotic” is a substance of natural, semi-synthetic or synthetic origin that causes the death of bacteria or delays their growth.

Bacteria are a large group of living microorganisms capable of causing infectious and inflammatory processes in the human body. You can see the bacteria in a microscope with special staining methods, as well as identify the DNA of the pathogen using a modern method of laboratory diagnostics – polymerase chain reaction.

Bacteria exist in the form of coccoid and rod-shaped forms, spiral-shaped, can exist extracellularly and intracellularly (pathogens of chlamydia, mycoplasmosis, gonorrhea). So:

Coccoid forms of bacteria – staphylococci, streptococci, meningococci, pneumococci, enterococci, gonococci. They cause diseases such as sore throats, sinusitis, pneumonia, meningitis, gonorrhea, enterocolitis, pustular skin diseases.

Rod-shaped bacteria (bacilli) are pathogens of typhus, salmonellosis, tuberculosis, diphtheria, dysentery, infectious and inflammatory diseases of the intestine, skin and subcutaneous tissue.

Spiral-shaped microorganisms. They can cause syphilis, lyme borreliosis, leptospirosis, cholera.

According to the ability to perceive Gram coloring, microorganisms are gram-positive and gram-negative. If necessary, the presence of oxygen for vital activity – aerobic and anaerobic. Most bacteria are mobile.

There are absolutely pathogenic strains of microorganisms that in any case cause a pathogenic process, and conditionally pathogenic ones that can cause inflammation depending on the number of microbes (the degree of contamination) in a certain state of the body. Diseases caused by conditionally pathogenic microorganisms largely depend on the state of general and local immunity (intestinal mucosa, respiratory tract, skin, genitourinary tract).

The spectrum of action of antibacterial drugs can be selective and wide. In the first case, antibiotics can affect mainly the coccal flora, gram-negative or gram-positive, anaerobic, the causative agent of tuberculosis. Broad-spectrum antibiotics can cause the death or inhibition of the growth of most bacteria. Antibacterial medications do not affect viruses, protozoa and fungi.

Antimicrobial drugs

Antimicrobial agents on the spectrum of exposure can affect not only bacteria, but also pathogens of mycoses, viral diseases and protozoal infections (caused by protozoa).

The causative agents of mycoses are yeast-like and mold-like fungi, dermatophytes. Yeast causes candidiasis of the skin and mucous membranes, less often – internal organs. Dermatophytes provoke various fungal diseases of the skin, hair, nails.

There are also pathogens of deep mycoses – rare diseases that are caused by fungi (sporotrichosis, aspergillosis, actinomycosis and others). This group of mycoses is almost always associated with immunodeficiency of various origins.

Viruses cannot be called microorganisms, since they are able to multiply and cause a pathological process only inside the host cell. Nevertheless, antimicrobial medications can cause the death or delay of reproduction and pathogens of viral diseases (influenza, ARVI, herpesvirus infections, hepatitis B and C, HIV infections).

The antimicrobial drug is able to suppress infections caused by protozoa, including pathogens of trichomoniasis of the genitourinary system, giardiasis of the intestine and biliary tract, malaria, leishmaniasis, toxoplasmosis.

Thus, the spectrum of influence of antimicrobial agents is much wider than that of antibacterial agents. At the same time, antibacterial drugs are one of the groups of antimicrobial agents.

Determining the difference

The main differences between antimicrobial and antibacterial drugs are:

  • purposes of prescribing medicines;
  • formation of resistance;
  • the method of obtaining substances.

Purpose of prescribing medications

The group of antimicrobial agents includes not only drugs for chemotherapy of infectious and inflammatory diseases, but also disinfectants with antiseptics. The main purpose of using disinfectants is disinfection and prevention of infectious diseases, nosocomial infections.

Antiseptics serve both for the treatment (mainly external – wounds, burn surfaces, trophic ulcers, mucous membranes of the throat and genitourinary tract) and for the prevention of infection.

The main purpose of antibacterial drugs is the treatment of infectious processes. With a preventive purpose for oral administration, these drugs are prescribed extremely rarely, according to special epidemiological indications. For example, when bitten by ixodes ticks for the prevention of Lyme disease, after extensive surgical interventions, to prevent the development of sexually transmitted infections in partners.

So, antibacterial drugs and antimicrobial drugs differ in the purpose of appointment.

Formation of resistance

Most antiseptics have a wide spectrum of action. The resistance of microorganisms to antiseptics is formed less often and weaker than to antibiotics. Therefore, in bacteriological studies for the identification and sensitivity of the causative agent of infection, tests are carried out mainly with antibacterial drugs and synthetic antimicrobials from the group of fluoroquinolones.

Thus, resistance to antibiotics in microbes is formed more often than to antimicrobial ones from the group of antiseptics, uroseptics, fluoroquinolones and disinfectants.

Methods of obtaining medicines

Antibiotics and antimicrobial medicines also differ in the method of preparation.

Antibacterial drugs are synthesized in three ways:

Biosynthesis. Its essence lies in the cultivation in conditions of special production of microbes that form antibiotics in the process of their vital activity. This is how natural antibiotics (penicillin, cephalosporins, tetracycline, streptomycin, polymyxin) are obtained.

Biological synthesis in combination with chemical reactions that change the molecule of a natural antibiotic and contribute to improving its antimicrobial activity. In this way, semi–synthetic antibiotics are obtained – ampicillin, oxacillin, amoxicillin, doxycycline, carbenicillin, gentamicin.
Chemical synthesis. The molecules of synthetic antibacterial drugs are formed by chemical reactions. Examples are chloramphenicol (“Levomycetin”), quinolones and fluoroquinolones (“Ciprofloxacin”, “Levofloxacin”, “Augmentin” and others).

Antimicrobial medicines – sulfonamides, nitrofurans (Furazolidone, Nifuroxazide, Furagin), 8-hydroxyquinolines (Nitroxoline), nitroimidazoles (Metronidazole, Ornidazole, Tinidazole) are synthesized chemically. Antiseptics (ethyl alcohol, hydrogen peroxide, iodine preparations) and disinfectants (“Chloramine”, “Alaminol” and others) are obtained only by chemical means. You can view the full list of antibiotics on the website –

Thus, the list of the main differences between antibacterial and antimicrobial medicines includes the method of industrial production, the spectrum of action on pathogenic flora, the purpose of application, the formation of resistance of microflora that can cause infectious and inflammatory processes in the body.

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