Introduction to microbiology, separation and identification of microorganisms, areas where microbiology is used

Microbiology includes single-celled organisms called microorganisms, viruses, and fungi.


Escherichia coli. Foto: NIAID / NIH www.uni-kiel.de/download/pm/2014/2014-395-3.jpg

Microorganisms, the oldest living organisms, play a vital role in biochemical cycles and inhabit environments unsuitable for other organisms. Other organisms depend on microbes for various reasons.

There are two primary reasons for studying microorganisms:

1. Microorganisms serve as models to understand cellular processes within both single-celled and multicellular organisms, providing insights into fundamental life phenomena.

2. The application of knowledge about microorganisms benefits humanity significantly, particularly in medicine, agriculture, and industry. Microorganisms are poised to play an increasingly crucial role in the future.

Microorganisms are broadly classified into three categories:

1. Prokaryotes, such as bacteria.

2. Eukaryotes, including fungi and molds.

3. (Viruses).

Microscopes, both light and electron microscopes, are used to observe microorganisms at the microscopic level.

Scanning electron microscope (SEM) and



There is a transmission electron microscopy (TEM).

The primary distinction between a scanning electron microscope and a transmission electron microscope lies in the observation method.

A scanning electron microscope (SEM) is utilized for surface imaging, providing detailed views of the external features of specimens. In contrast, a transmission electron microscope (TEM) is employed for examining internal structures and components of specimens at a much higher magnification.

Microbes play significant roles in various industries, exerting substantial influence and contributing to numerous processes.

Alexander Fleming, credited with the discovery of penicillin, revolutionized medicine with his groundbreaking work on antibiotics. This discovery marked a significant milestone in medical history, as antibiotics became one of the most influential and transformative developments in healthcare. Antibiotics have saved countless lives by effectively treating bacterial infections and have become indispensable tools in modern medicine. Fleming's pioneering research laid the foundation for the development of numerous other antibiotics, shaping the way infectious diseases are treated and controlled worldwide.

Indeed, the development of antibiotics from penicillin to more potent drugs like methicillin and vancomycin has been crucial in combating bacterial infections. However, the emergence of antibiotic-resistant microorganisms poses a significant challenge to healthcare systems worldwide. 

Microorganisms possess the ability to evolve and develop resistance to antibiotics through various mechanisms, including genetic mutations and the acquisition of resistance genes from other bacteria. As a result, some bacteria have become "superbugs," resistant to multiple antibiotics and difficult to treat.

The rise of antibiotic-resistant bacteria has led to serious public health concerns, as infections caused by these pathogens can be more challenging to manage and may lead to severe complications, including septicemia (sepsis), a life-threatening condition characterized by systemic inflammation and organ dysfunction.

Addressing the threat of antibiotic resistance requires a multifaceted approach, including judicious antibiotic use, surveillance of antibiotic-resistant bacteria, development of new antibiotics and alternative treatment strategies, and implementation of infection prevention and control measures in healthcare settings. It is essential to prioritize efforts to combat antibiotic resistance to ensure effective treatment of bacterial infections and safeguard public health.

Antibiotics have advanced significantly from penicillin to methicillin and vancomycin. However, as microorganisms evolve and develop resistance, the emergence of super bacteria poses a serious threat. These bacteria evolve into pathogenic strains capable of causing conditions like septicemia (sepsis).




In agriculture, antibiotics are commonly administered to livestock such as cattle, pigs, and poultry to enhance livestock efficiency. However, as seen in medicine, the use of antibiotics in animals can lead to the development of antibiotic resistance. This resistance can be transmitted to humans through consumption of meat and other animal products, potentially leading to secondary resistance in human populations.

The representative industrial use of microorganisms is their utilization in the production of ochre.

One notable example occurred in Finland during World War II. Finland, initially allied with Nazi Germany to resist Soviet interference, later shifted allegiance as the war progressed. When the tide turned in favor of the Allied Powers, Finland ended its alliance with the Nazis and expelled German forces.

Ochre, a reddish-brown pigment, is used to combat phenomena such as red tide and green algae. This is because ochre contains high levels of antibiotics, attributed to the abundance of actinomycetes, microorganisms known for their antibiotic properties and characteristic soil odor. 

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