THE CONCEPT

 

Antibiotics (Greek: ἀντι anti, "against" and βίος bios, "life") are a category of medications that act against bacteria and parasites. The antimicrobial effects of Penicillin, discovered in the early 20th century, have led to the widespread use of Antibiotics in the clinical treatment of infections nowadays.

​

This article will describe the basic physiological relations of bacteria and humans as well as describe some of the management options for bacterial infection in accordance with current medical practice recommendations.

​

 

BACTERIA IN HUMANS

 

Bacteria are a regular part of the human body and help the organism with many functions including digestion, tissue integrity, and immune functions. Those bacteria usually live in symbiosis with their human host and do not have any harmful effect on body functions.

​

Other bacteria, however, can enter the body through the respiratory system, the skin, the digestive system, wounds, or other pathways such as sexual interaction, infect the body and lead to illnesses and diseases.

Common bacterial wound infections are caused by: Staphylococcus aureus, Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Corynebacterium spp. 1

​

​

THE BACTERIAL CELL

​

STRUCTURES 2

Bacteria have specific structural characteristics that provide them with their morphological features.

​

Capsule: The outermost layer of many bacteria that protects them from external factors. It is made from polysaccharides (carbohydrates) and is not present in all bacterial types.

​

Cell wall: Another protective barrier that is made from peptidoglycans. This structure also helps maintain the bacterial cell's shape. This cell wall has different thicknesses in various bacteria and can be stained (colored) for viewing under a microscope using a so-called “Gram-staining”. Bacteria that have a thick cell wall and react to this staining are called “Gram-positive”.

​

Cell membrane: The innermost layer of the cell. It is composed of a double layer of phospholipids and is fluid in nature.

​

Nucleotide: Unlike humans, bacterial cells do not have a nucleus. Their DNA is suspended freely in the cellular fluid. This DNA contains the bacterial genetic code with all information about the cell and its proteins.

​

Pili: The bacterial cell has spike-like projections, so-called pili, that extend outward from the cell's membrane. They help in attaching the bacterium to other structures and aid in cell-to-cell recognition and reproductive function.

Ribosomes: They translate the bacterial genetic code into an amino acid chain that after being folded creates proteins. These proteins are three-dimensional structures that can perform functions in bacterial metabolism.

​

Flagellum: Long projections that are motile, enabling the bacterium to move through a liquid medium.

​

​

MORPHOLOGY

​

Bacterial cells have varying morphologies (appearances). The three most common categories are bacilli, cocci, and spirilla.

Cocci: Those bacteria appear spherical in shape. Common bacteria of this type are staphylococci, which can cause various infections including urinary tract infections, food poisoning, gonorrhea, throat infections, and even pneumonia.

​

Bacilli: These bacteria are rod-shaped and almost exclusively Gram-positive. A well-known bacillus is Bacillus Anthracis, which causes Anthrax. 3

​

Spirilla: Their spiral-form shape is very characteristic. One of the well-known bacteria of this type is Helicobacter pylori, which lives naturally in the human stomach. It is usually asymptomatic, however, can cause Gastritis and stomach ulcers.

​

​

ANTIBIOTICS

​​​CLASSIFICATIONS

The goal of the antibiotic is to disrupt the cellular activity of the bacterium in order to inhibit specific functions. Antibiotics can attack various targets within the bacterial cell. 
In order to make the very complex classification easier to understand, this article shows a target-based classification model. 

Cell wall/membrane synthesis

These antibiotics inhibit the formation or maintenance of the cellular wall and membranous structures.

Examples: Beta Lactams (eg. Penicillins), Vancomycin, Bacitracin, Polymyxins, and Daptomycin.

DNA/RNA Synthesis

These antibiotics inhibit the formation of DNA or RNA within the bacterial cell, which inhibits protein formation.

Examples: Folate Synthesis (Sulfonamides, Trimethoprim), Fluoroquinolones, and Rifamycins.

Folate Metabolism

These antibiotics inhibit the formation of Folic Acid, which is essential for the survival of the bacterium.

Examples: Trimethoprim, Sulfonamides.

Protein Synthesis

These antibiotics inhibit protein synthesis, which hinders the bacterium from performing biological processes.

Examples: Linezolid, Tetracyclines, Macrolides, and Aminoglycosides.

 

​

ANTIBIOTIC RESISTANCE

​

Antibiotic resistance occurs when a bacterium is not affected by an antibiotic agent. This phenomenon can occur when a bacterial colony has been exposed to a certain antimicrobial agent before or mutated variants of the bacterium have arisen through genetic mutation.

​

This represents a huge problem for medical personnel, as antibiotics lose their healing abilities when confronted with those resistant bacteria. Treatment can then no longer be effectively administered.

To slow down antibiotic resistance in bacteria it is important to limit the use of antibiotic agents when not directly necessary in the treatment process. Also, switching antibiotics routinely will help prevent antibiotic resistance, as the bacteria resistant to one type of medication can be killed by another.

​

​

TREATMENT GUIDELINES

​

TCCC GUIDELINES

​

The JTS TCCC Guidelines recommend Moxifloxacin PO (per-orally) or Ertapenem IV (intravenously) for all open combat wounds. 4