Prevention and Treatment of Diseases Caused by Microorganisms

Since ascertainment of microorganisms is the cause of certain diseases, a lot of attention has been paid to the prevention and treatment of these diseases. The etiological causes (causative agents) for some causes of bacterial diseases such as bubonic plague, diphtheria, smallpox, and cholera, which are known until now, are diseases that have been discovered for centuries.

Some prevention and treatment methods aim to eradicate diseases caused by microorganisms developing until now, among others, immunization (eg vaccination), antiseptic (ways to exclude or reduce the possibility of infection), chemotherapy (treatment of patients with chemicals), and health methods in the community (for example water purification, waste disposal, and food preservation).


Pasteur continues his discovery of the causes and prevention of infectious diseases. Around 1880 Pasteur isolated the bacteria that cause chicken cholera and grew it in pure culture. As proof that Pasteur has succeeded in isolating the bacteria that causes the disease, Pasteur uses the basic techniques proposed by Koch.

The figure below illustrates a series of experiments conducted by Pasteur in front of the community in a demonstration. Beginning with the injection of pure culture of healthy chickens, until it is waited until it is attacked by cholera chicken, which will eventually die. It turns out that the chickens did not become sick let alone die. After tracing each step in the experiment, it was discovered that a culture had been inadvertently stored for several weeks. Not a fresh culture specifically grown for the experiment. The experiment was repeated with two groups of chickens. The first group was initially inoculated with ineffective old cultures and the second group, which had never been treated before. Then the two groups were inoculated with bacteria from fresh and new cultures. The second group became sick and died, but the first group remained healthy. This caused Pasteur to be puzzled, but his explanation was soon known. Pasteur found that bacteria can lose their virulence, or their ability to cause disease, after being allowed to grow and grow old. The patented (less virulent) bacteria can still stimulate its host (in this case chicken) to form antibodies which are protective substances for the host against subsequent infections by virulent organisms or the same bacteria.
Picture: Two Groups of Chickens, Pasteur Experiment.
Picture: Two Groups of Chickens, Pasteur Experiment.

The principle of immunization as demonstrated by Pasteur, is as follows. At first the chickens were inoculated with cholera bacteria a few weeks old but the chickens were still healthy. A few weeks later, Pasteur inoculated the chickens with a fresh culture of chicken cholera bacteria. This fresh virulent culture does not make chickens sick, but kills chickens that have not been inoculated with a culture that was previously patented. This experiment showed that the old chicken cholera bacterial culture was unable to cause disease, but could cause the chicken to produce a protective substance called an antibody in its blood.

In the next step Pasteur applied the principle of inoculation with patented culture (attenuated so that it became less virulent) against anthrax prevention, and it worked. The patented bacterial culture is called a vaccine (a term derived from the Latin vacca meaning cow) and immunization with a patented bacterial culture is called vaccination. Pasteur supports the opinion of Edward Jenner (1749-1823) who had succeeded in vaccinating a boy against smallpox in 1796.

Pasteur became famous throughout France, and many people thought he could do wonders with bacteria and control infection. It is not surprising that Pasteur was told to make a vaccine for hydrophobia or rabies, a disease that is transmitted to humans through the bite of a dog, cat, or other animal. Although the cause of rabies is unknown, Pasteur has the belief that the cause of the disease is microorganisms. Pasteur tried to make a vaccine that began by inoculating the rabbit by injecting the rabbit with the saliva of a mad dog. In the end the rabbit died, then Pasteur removed the brain and nerve fibers of the spine of the rabbit, then dried for several days, finely ground, and suspended in liquid. Dogs that are inoculated with this mixture become protected from rabies. In the next step the vaccine was also tried for the first time to a child named Joseph Meister who was bitten by a crazy dog and the child survived.


At the same time, Elie Metchnikoff (1845-1916), who worked in the Pasteur laboratory, observed that leukocytes, a type of cell in human blood, can eat bacteria that cause disease in the body. This protection against infection is called phagocytes or cell eaters and the process is called phagocytosis (Figure). According to these observations, Metchinikoff hypothesized that phagocytes are the most important first line of defense for sufferers against microorganisms that attack their bodies. Phagocytosis is a natural defense mechanism against disease. A series (three steps) of the phagocytic process is shown in the following figure, which is the ingestion (ingestion) of particulate matter by specific cells.
Picture: Phagocytosis
Picture: Phagocytosis


In a general sense, the word septis means infection, antiseptic are ways of eradicating or preventing an infection. In the 1860s a British surgeon, Joseph Lister (1827-1912), studied how to keep microorganisms away from wounds and nicks made by surgeons. This happens because the number of cases of death due to surgery is very high, for example in 1864, Lister noted 45% of patients themselves died after surgery. At that time disinfectants were unknown, but it was already known that carbolic acid (phenol) had the ability to kill bacteria. Finally Lister decided to use the dilute acid solution to soak the surgical equipment and spray the operating room. Injuries and nicks on the patient's body that are protected in this way, rarely cause infection and accelerate the patient's recovery. So brilliant was the success that the technique was quickly accepted by other surgeons. It is this antiseptic practice that underlies the principles of today's aseptic techniques that are used to prevent the entry of microorganisms into a wound or incision.

Now many chemicals such as alcohol, iodine solution, and also physical techniques such as the use of air filters and germicidal ultra violet lamps (can kill germs), can be used to reduce the number of microorganisms in places such as surgery rooms and children's rooms for the care of premature babies .


Chemicals have been used for a long time to eradicate diseases, such as mercury used to treat syphilis since 1495 and Kina's gotu kola in South America used since the 17th Century to fight Malaria. However, only after there was research and brilliant writing by the German physicist Paul Ehrlich (1845-1915), modern chemotherapy began. Ehrlich's research aims to develop chemicals that are capable of killing certain microorganisms without harming patients. Ehrlich systematically synthesized hundreds of compounds in his search for potential chemotherapeutic agents. In 1909 it was discovered that the Salvarsan arsenic compound, the 606th compound of a series synthesized by Ehrlich, was able to kill the bacteria that cause syphilis.


During the period 1860 and 1900, many important basic discoveries were made. The development of the disease germ theory in 1876, suddenly aroused interest in laboratory procedures to isolate and characterize microorganisms. During this period many microorganisms were found to cause disease and methods to prevent, diagnose and treat these diseases. The discoveries in the field of medical microbiology brought a large and rapid overhaul of medical practice. The discovery of various bacterial staining methods also strongly supports the development of research on disease, especially after the discovery of agar media for the growth of microorganisms.

Microorganism studies in the laboratory are carried out for various purposes. One example is to determine the characteristics of microorganisms that differ morphologically, or to determine the physiological processes carried out by microorganisms. In general the methods available to microbiologists make it possible to characterize microorganisms.