Microbiological infections, as the name suggests, are the caused by microorganisms. Infection is an invasion of microorganism into one’s body to cause harm. These microorganisms, also called pathogens, use the host body to sustain themselves, reproduce and colonize. These infectious microorganisms are also called as pathogens.
Examples of pathogens include:
- Bacteria
- Fungi
- Viruses
- Parasites
Each pathogen differs from the other in several ways, including size, shape, function, genetic content, and how they act on one’s immune system etc.
How do these infections spread?
These infections can spread in several different ways, including through:
- Skin contact
- Transfer of bodily fluids
- Contaminated food and water
- Inhaling airborne particles or droplets
- Getting in contact with the objects that are touched by infected person
- Faeces
What does the pathogen do to the body?
When a pathogen enters the body, our body’s immune system acts as an effective barrier against it and fights it off. A few infections are mild and can be handled by our body’s immune system. However, certain pathogens may be virulent and can be in high numbers, causing serious and life-threatening infections. Apart from causing harm to the host cells, these pathogens may weaken the body’s immune system’s ability to fight them off. At this point, the infection turns harmful and need an external intervention in terms of antibiotic medications.
Different types of infections
Infections are classified into different types based on the infecting organism. They are:
Bacterial infections – Bacteria are single celled microorganisms that can live in almost any type of environments, from extreme heat to intense cold. Not all bacteria cause infections. A few are necessary for healthy growth of an individual such as Lactobacillus (a type of bacteria found in stomach that helps prevent gut lining from damage). However, a few strains of bacteria may cause diseases, that may range from mild to severe. A few of these bacteria may also take shelter inside the human body, without causing harm.
A few life-threatening diseases that bacteria can cause are – cholera, diphtheria, typhoid, dysentery, tuberculosis etc.
Bacterial infections are treated with the help of antibiotics. However, a few strains of bacteria tend to develop resistance against the treatment and survives.
Viral infections – Viruses are tiny microorganisms with a small piece of genetic code, and a coat of protein that protects it. Viruses invades the host and gets attached to the host cell. As they get attached to the cell, they slowly release their genetic material into the host cell thereby forcing the cell to replicate the virus and multiply their number. As the number of viruses increases, the cell bursts, in turn releasing these viruses to the new host cells, spreading the infection.
A few viral infections include common cold, encephalitis, meningitis, gastroenteritis, COVID-19 etc.
Viral infections are treated with the help of antiviral medications. However, a few strains of virus may develop resistance to the treatment and survive.
Fungal infections – These infections are caused due to fungi. A fungus is a long and cylindrical microorganism, with small filaments branching from the main body, that can decompose and absorb organic matter using enzymes. However, a few fungi, such as Yeast are single-celled. These microorganisms reproduce by spreading spores either in air or water.
Fungal infections can be caused in any part of the body including, upper layers of skin to systemic infections.
Examples of fungal infections are
candidiasis, athlete’s foot, ringworm, eye infections etc.
In general, high risk of antifungal infections can be seen with:
- Excessive usage of antibiotics
- Highly weakened immune system, such as HIV
- Transplantation, as involves medicines that supresses one’s immune system.
Other infections – The above-mentioned infections are the commonest of infections observed in individuals. However, there are others that can have serious effects on the body. Protozoan infections are one amongst them.
Protozoa are single celled microorganism with a nucleus that shows similar features to those of animals, such as mobility and independent existence without the need of host. These are commonly found in places with poor hygiene, and spreads to other humans through faeces.
Amoebic dysentery is one of the examples of protozoal infections.
Helminths that includes flatworms and ringworms may also cause infections in humans.
Ectoparasites such as ticks, mites, lice etc are also another type of microorganism that causes infection by attaching or burrowing into the skin.
Symptoms of microbiological infections
Symptoms of a particular infection depends on the microorganism responsible for it. Typical symptoms of different types of infections include:
Bacteria – Bacterial infection symptoms include redness, heat, swelling, fever and pain at the site of infection with inflammation of lymph glands.
Virus – Viral infection symptoms include fever, headache, body ache, sore throat, sneezing, cough, diarrhoea, vomiting etc.
Fungi – Fungal infections are usually indicated by a rash on the skin or the affected body part. Although, a few other symptoms like itching, redness, scaly skin, swelling and blisters can also be noticed at the site of infection.
How are these infections diagnosed?
The diagnosis of these infections can be made through culture examinations of blood and urine.
Blood culture test
This is a routine test that checks the blood samples for the presence of any germs or microorganisms in it that could damage the body’s immune system and internal organs.
Procedure:
Blood sample is drawn by inserting a needle into your vein. The blood sample is mixed with a special material called culture. This culture helps bacteria to grow if they are already present in the blood.
Interpretation of the results:
Results are usually given out as either positive and negative to blood cultures. A positive test results indicate there are bacteria or yeast present in your blood.
A negative test result indicate there is no sign of microbial infection in your blood.
Urine culture test
This is a routine test that checks your urine samples for the presence of any germs or microorganisms that can cause infections such as Urinary tract infections (UTI).
Procedure:
Urine samples are collected in several ways that includes, clean catch, urinary collecting bag, catheter, and suprapubic aspiration. However, clean catch method is the widely used one.
In this procedure, an individual is provided with a sterile container and asked to collect their urine in a way that it should be free from outside contaminants, such as bacteria that live on your skin. This collected sample is then sent to laboratory and are checked for presence of any possible pathogens in it.
Interpretation of results:
Results are generally given out as positive or negative.
A positive test result indicate you have microorganisms found in your urine sample. This suggests you likely have urinary tract infection or bladder infection.
A negative test result indicates there is no sign of microbial infection in it.
These cultures (blood and urine) are advised to the individuals who presents with signs and symptoms of infections such as fever, rash, pain, diarrhoea etc. Information from these tests helps your healthcare provider in choosing best possible treatment to clear up your infection. These cultures are also advised after treatment to ensure the infection is completely gone.
