An infection refers to the colonization that external species perform in an organism that in medical terms is called a host, being these absolutely detrimental to the development and survival of a said organism.


Infection (from Latin infectio) is the action and effect of infecting or becoming infected.

This clinical concept refers to the colonization of an organism by external species.

Said colonizing species are detrimental to the normal functioning of the host organism.

Invasion of germs or pathogenic microorganisms (bacteria, fungi, viruses, etc.) that reproduce and multiply in the body causing a disease.

What are the symptoms of an infection?

To local cellular lesions, to the secretion of toxins from the pathogenic microorganism or to the antibody-antigen reaction of the immune system.

The infections

The severity of the infection will vary according to the aggressiveness of the intruder microorganism and of course the immune status of the host, although of course, it is also plausible that the level of aggression of the foreign species that invades is so important that not even a good system immune can fight it.

There are a huge amount of infections that will particularly affect every part of a human being’s organism, while one of the most common bacterial infections and for which people most consult and undergo treatment is a urinary infection.

All multicellular organisms experience some degree of colonization by external species.

However, this relationship is symbiotic and does not have harmful consequences for the guest.

When colonization generates abnormalities (such as pain, irritation, etc.), an infection occurs.

Active infection involves the struggle between the host and the infecting organism, which tries to multiply.

The passage from a symbiotic colonization to an infection depends on various circumstances and conditions.

Why is an infection called

It is called infection to a process in which there is repopulation of a set of organisms or external agents that are introduced into the body, in the field of medicine these organisms are known by the hostname and are considered as harmful agents of a form that is very relevant to the health of the person who acquires them, and may even harm the correct functioning, survival, and development of the aforementioned organism.

These organisms foreign to the body can enter the body through different access routes, such as skin lesions, through the respiratory tract (nose and mouth), which generates in the infected several changes in their organs and functions.

Of these, these agents move throughout the body, as well as their waste through the blood transport routes or the lymph.

How an infection starts

An infection begins with the entry of the pathogen into the body and continues with an incubation period.

From then on, the type of infection is determined by the number of germs, their multiplication capacity, and their toxicity.

The clinical manifestation caused by an infection due to the action of viruses, bacteria, fungi or other organisms is known as infectious disease.

Infections in the body

Many of the bacteria that cause it comes from the large intestine, entering the bladder in an ascending manner after an initial passage through the urethra, thus colonizing both the urethral and periurethral regions.

Although the urinary system has certain mechanisms of its own, such as the constant flow of urine that acts by dragging, to combat the action of incoming bacteria, in some circumstances, bacteria can overcome these hard barriers, causing inflammation of the area, which according to the magnitude and location that it holds will materialize in the following clinical cases: prostatitis, asymptomatic bacteriuria, acute cystitis and acute pyelonephritis.

Main causes of infection

Among the main causes of this type of infection is some type of obstruction, such as tumors, stones or cysts, which hinder the normal flow of urine, age, with older adults being more prone to show the same, genetic predisposition and diabetes.

Meanwhile, for a better detection and diagnosis of the same, doctors will ask the patient to present the symptoms, to undergo a test called uro culture and that involves taking a urine sample in especially sterile conditions, the morning urine is the best, after hygiene of the genitals.

What is the difference between a bacterial infection and a viral infection?

Bacterial infections are caused by bacteria, and viral infections are caused by viruses. Perhaps the most noticeable difference between bacteria and viruses is that antibiotics usually kill bacteria, but they are not effective against viruses.

Bacteria are unicellular microorganisms that proliferate in many different types of environments.

Some varieties live in extreme cold or heat. Others are lodged in the intestine, where they intervene in the digestion of food.

Most bacteria are not harmful to humans, but there are exceptions.

Some of the infections caused by bacteria are the following:

  1. Streptococcal tonsillitis
  2. Tuberculosis
  3. Urinary infections

The inappropriate use of antibiotics has helped to create bacterial diseases that are resistant to treatment with different types of antibiotics.


Viruses are still smaller than bacteria and need living hosts – such as humans, plants or animals – to multiply.

Otherwise, they can not survive. When a virus enters the body, it invades some of the cells, takes over the cellular machinery and reorients it to produce the virus.

Diseases caused by viruses include the following:

  1.  Chickenpox
  2. AIDS
  3. Common cold

In some cases, it can be difficult to determine if the cause of the symptoms is a bacteria or a virus.

Many conditions-such as pneumonia, meningitis, and diarrhea may be caused by bacteria or viruses.

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