Streptococcus and its types – causes of infections, symptoms and treatment [WE EXPLAIN]

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Streptococcus is a bacteria that attacks our body, especially when the immune system is weakened. The human body can become infected with several types of streptococci. Infections, infections, diseases or complications depend on the species of streptococcus that attacked us. What diseases does streptococcus cause? How to recognize a streptococcal infection? How is such an infection treated?

Characteristics of streptococci

Streptococcus belongs to the group of gram-positive bacteria. Streptococci are also known as streptococci. The Latin name streptococcus comes from the Greek streptos and means something that bends easily and agile.

Streptococci are aerobic or relatively anaerobic spherical bacteria that divide along one axis. Therefore, streptococci grow either in chains or in pairs. Streptococci show considerable variation among themselves.

Systematics of streptococci it has changed many times over the past decades. The basic division of streptococci is that resulting from the type of hemolysis. Given this criterion, streptococci are divided into:

1. streptococci γ – no visible hemolysis;
2. streptococci α – partial hemolysis – is caused by the reduction of iron in hemoglobin. Haemolytic alpha streptococci cause common diseases in humans;
3. β streptococci – complete haemolysis – beta haemolysis is associated with the complete disruption of the red blood cells, which gives distinctive bright areas around the bacterial colonies. In medicine beta hemolytic streptococci groups A and B are of the greatest importance.

In the classification of streptococci, the division into phylogenetic groups is also used. Within this division, the following are distinguished:

1. pyogenic group;
2. anginosus group, also called “milleri”;
3. mild/oral group;
4. group salivarius;
5. bovis group.

The β-hemolytic streptococci referred to in this article are members of the pyogenic group and part of the anginosus group. This type of streptococcus can be divided into smaller subgroups, and the division criterion is the polysaccharide present on their surface, i.e. the Lancefield antigen.

The Lancefield antigen distinguishes between groups of streptococci, which are classified into groups ranging from group A to group O. Streptococci that can cause disease in humans are group A, group B, and groups C and G. Other groups of streptococci include the increasingly dangerous zoonotic pathogens.

What are the most common bacterial diseases? Read: The most common bacterial diseases – overview and characteristics

Group A streptococci – purulent streptococcus

Group A streptococci are commonly known as pneumococci. This type of streptococcus is most common in the nasal cavity and throat of children and healthy and adult people. This bacterium is usually responsible for the emerging infections of the mucous membranes of the upper respiratory tract and the skin. Statistics show that annually about 600 million people worldwide suffer from streptococcus, while skin diseases caused by this bacterium affect about 100 million people.

Diseases caused by purulent streptococcus are usually quite mild and their treatment is usually short and not complicated. Strains of this streptococcus are sensitive to penicillin. However, if treatment is not given promptly, streptococcal infection can lead to serious autoimmune complications.

The ability to penetrate, multiply and damage tissues of an infected organism in the case of streptococcus depends on the type of surface protein.

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Group A streptococci – diseases

Group A streptococcus causes diseases that mainly affect the mucous membranes of the upper respiratory tract and the skin. This streptococcus is also responsible for numerous complications that may turn out to be dangerous to the health and life of the patient. The diseases caused by purulent streptococcus include:

1. purulent sore throat – is a disease commonly known as purulent angina. The symptoms of streptococcal angina are very severe for the patient. There are: very severe sore throat, very high fever, chills, a feeling of crash, vomiting, enlargement and painfulness of the lymph nodes and a white coating on the tonsils;
2. urinary tract infections – Streptococcus can cause many clinical forms of urinary tract infection, such as: urethral abscess, cystitis, acute or chronic prostatitis, abscesses of the prostate gland, scrotum, kidney, perirenal or retroperitoneal, pyelonephritis and others;
3. rheumatic fever – occurs as a complication of acute pharyngitis caused by streptococci. The essence of the disease is inflammatory changes in the connective tissue of the heart and vessels, where cellular infiltrates are formed that die and scar. Rheumatic fever appears about 3 weeks after streptococcal pharyngitis; 
4. scarlatina – the source of infection in the case of scarlet fever is a person suffering from strep throat or scarlet fever. You can get infected by airborne droplets, and the disease itself hatch for a very short time, already in the first day after infection. The main symptom of scarlet fever is fever, followed by a rash in the following days. The appearance of a rash depends on the patient’s sensitivity to the toxin produced by streptococci. The disease may be accompanied by vomiting, abdominal pain and sore throat;
5. impetigo – is a disease that is very infectious. The streptococcal impetigo is characterized by skin lesions in the form of small, focused, superficial and rapidly bursting blisters. These changes quickly take the form of scabs. Impetigo can often be accompanied by fever;
6. otitis media – this disease is one of the most common complications of an untreated cold. Streptococci then enter the middle ear and cause inflammation with a build-up of exudate. Otitis media can be recognized by very severe pain that increases at night, fever and often nausea and vomiting. In the course of the disease, due to the increasing pressure in the middle ear, the tympanic membrane may rupture and pus may leak;
7. sepsis – is an infection of the body, which is often fatal. In the diagnosis of blood sepsis, the presence of streptococci is confirmed, although the presence of bacteria in the blood is not necessary for the diagnosis of infection.
8. endocarditis – Streptococcal endocarditis may occur as a consequence of sepsis. In this case, streptococci attack the body and cause inflammation of the endocardium and the heart valves;
9. glomerulonephritis – is a group of diseases characterized by inflammation of the glomeruli, which in turn causes abnormal kidney function;
10. necrotizing fasciitis – is a type of rare, acute infection of the subcutaneous connective tissue that spreads along the fascia that covers the muscle groups of the torso and extremities. 

An adjunct in the treatment of streptococcus can be used tea on lamella, which has a beneficial effect on the digestive and urinary systems.

What should you know about bacteria in urine? Check: Are bacteria in urine dangerous?

Group B streptococcus – lactic acid streptococcus

Group B streptococci, or GBS for short, are often not considered dangerous because they are part of the intestinal flora. They are also found on human skin. They can be observed even in every third person. Until the beginning of the 70s, this species of streptococcus was considered a bacterium that functions in symbiosis with the human body and feeds on unused food products. Streptococcus was also treated as a cattle pathogen responsible for inflammation of the mammary gland.

However, at the end of the 60s, an increasing number of infections in newborns, caused by group B streptococci, began to be observed. streptococcus from mother to child.

Infections with group B streptococcus they do not only concern infants. As with group A streptococci, adults are also infected. Most often, such infections occur in elderly people, with impaired immunity or with metabolic disorders.

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Group B streptococci – diseases

Group B streptococcus is a bacterium that primarily causes disease in newborns. Of course, there are also cases of illness among adults. Among the diseases caused by group B streptococcus are:

1. neonatal group B streptococcal infection – caused by bacteria carried by up to 35% of pregnant women. Most often, a baby is infected while passing through the birth canal. A streptococcal infection can lead to either asymptomatic carrier or acute disease. Acute disease usually occurs in cases of prematurity, low birth weight, premature rupture of the fetal bladder or diabetes in the mother. Infection is early and late. Early infection begins intrauterine or up to 7 days after delivery. It runs as sepsis. The late-stage neonatal streptococcal infection usually manifests itself after the first month of life, sometimes even in the third month of life. The symptoms of late infection are: inflammation, osteoarthritis, and meningitis;
2. meningitis – is a bacterial infection caused by streptococcus that affects the meninges that surround the brain and spinal cord. Symptoms of meningitis are fever, chills, vomiting, headache and a stiff neck. Patients are also irritable and hypersensitive to touch, sounds, smells and light. If appropriate treatment is not started, somnolence increases in the following days, eventually leading to loss of consciousness;
3. sepsis – is an infection of the body that very often ends in death. In the diagnosis of blood sepsis, the presence of streptococci is confirmed, although the presence of bacteria in the blood is not necessary for the diagnosis of infection;
4. pneumonia and breathing disorders – in the case of group B streptococcus infection, we are dealing with lobar pneumonia. The name of the disease is related to the fact that inflammation covers one (or sometimes more) lobes of the lung at once. The course of lobar pneumonia can be divided into three stages. In the first day, lung congestion occurs, then red hepatitis of the lungs occurs, and finally, when the blood cells are broken down, gray hepatitis of the lungs occurs. Lobular pneumonia presents with chills, shortness of breath, chest pain, cyanosis, high fever and a severe, deep, nagging cough;
5. bacteremia – bloodstream infection with streptococcus, confirmed by their isolation. Bacteremia may have no sequelae or complications. Unlike sepsis, there are no clinical symptoms due to the presence of streptococci in the blood;
6. urinary tract infections

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Group D streptococci – faecal streptococcus

Faecal streptococcus is a bacteria that occurs naturally in the human digestive tract. It might seem that since faecal streptococci occur naturally in the human body, they do not pose any threat to it. Actually, you can agree with this assumption, but the problem begins when fecal streptococci begin to multiply and move to other, unsuitable places for them, for example to the urethra or the mouth.

Faecal streptococcus is a bacterium that is very often referred to as the dirty hands bacteria. This means that the lack of hygiene or inadequate care for it contributes to the transport of streptococci to other, undesirable parts of the body. The easiest way to get infected with fecal streptococcus is swimming pools, playgrounds, in public transport or public toilets. Measuring clothes in stores can also be a threat.

Most often, fecal streptococci are transported to the urinary tract, which is why most diseases are related to this system. Faecal streptococcus can cause bladder infection and urethritis. This bacterium also causes bladder infections in pregnant women, which can be a hazard to a developing fetus. Fecal streptococcus also causes vaginitis, nephritis, and prostatitis.

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Streptococci from groups C and G.

Several species of streptococci are classified in groups C and G. Streptococci in these groups were initially considered to be pathogens in animals. However, these streptococci are now recognized as the etiological factors of numerous human infections. Streptococcus species belonging to groups C or G can be divided into two phylogenetic groups: pyogenic and anginosus.

Diseases that can be caused by streptococci of groups C and G:

1. lymphadenitis;
2. glomerulonephritis;
3. arthritis, connective tissue;
4. sepsis;
5. inflammation of the throat, lungs, joints, meninges, endocarditis;
6. streptococcal toxic shock syndrome (STSS).

How to properly care for personal hygiene? Read: Personal hygiene

What are the causes of streptococcal infection?

How is streptococcal infection? As already known, many species of streptococcus live and function in the human body. They are usually harmless and enrich the bacterial flora of the mouth, skin, intestines and respiratory tract. Likewise, streptococci that cause disease can be found in the body but never become active for years.

The way of spreading and infection with streptococcus is the droplet way. Therefore, contact with an infected person significantly increases the risk of developing the disease. It is not uncommon for an infected person to sneeze or cough for the streptococcus to spread to another organism. The risk of infection is much higher in children, seniors, and immunocompromised people, including the chronically ill.

A factor that increases the risk of infection with streptococcus is the lack of personal hygiene, not washing your hands before eating and not washing fruit or vegetables before eating them. In addition, large amounts of dairy products in the diet significantly increase the risk of streptococcal infection, as milk supports their development in the larynx, mouth and throat. Infection is also possible through the contact of damaged skin with a contaminated surface or objects with streptococcus bacteria.

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Streptococcus – diagnosis of infections of the upper respiratory tract

Diagnosing a streptococcal infection sometimes requires proper diagnosis. The presence of characteristic symptoms is an important element in the diagnosis of upper respiratory tract infections. The diagnosis is based on the use of the Centor scale, which describes five symptoms:

1. no cough;
2. enlarged lymph nodes in the neck;
3. the presence of a fever above 38 degrees Celsius;
4. white, purulent coating on the tonsils and their swelling;
5. patient age under 15 or over 44 years old.

1 point is awarded for each symptom found. If the sum of the points is 4 or 5, a doctor can diagnose a streptococcal infection in more than 50%.

To be sure, culture the throat and culture the bacteria on a special medium. It is also possible to take a blood test to check for the presence of antigens. It is a faster method than inoculation, but definitely less sensitive.

Why is it worth doing blood diagnostics? Check: Diagnostic tests

Streptococcus – how is it treated?

Streptococci are bacteria, so any infection requires the use of antibiotics. Streptococcal infections are usually treated with beta-lactam antibiotics such as penicillin, amoxicillin (sometimes in combination with clavulonic acid), and cephalosporins. Some streptococci, such as faecal streptococci, are resistant to beta-lactam antibiotics, in which case antibiotics from other groups should be used. In such cases, the doctor may suggest macrolides or quinolones.

Very often, in the event of a streptococcal infection, culture with an antibiogram is performed. The culture allows to find out which antibiotics a given streptococcus is most sensitive to. In this case, the treatment can be done with an antibiotic that will effectively and quickly combat the bacterial infection.

Very often, in the treatment of respiratory tract infections with streptococcus, non-steroidal anti-inflammatory drugs (e.g. with ibuprofen) are used, whose task is to reduce the severe pain and fever that accompany the infection.

What is worth remembering is that untreated group A streptococcal infections can penetrate deep into the body and cause inflammation of the lungs, meninges, bones and marrow, as well as necrotizing fasciitis, which is an acute infection of the subcutaneous connective tissue.

If you want to know more about antibiotics read on: Antibiotics – types, action, use and side effects

Streptococcus in pregnancy – is it dangerous?

Streptococcus in pregnancy can be dangerous because it can infect your baby during delivery. A significant proportion of women are unaware that streptococci live permanently in the body. They are not sexually transmitted, but as a result of multiplication or lack of proper hygiene, they can occur in the genital tract. Streptococci enter the genital tract through close proximity to the anus. Once in the vagina, streptococci can move quickly into the pelvis and endanger the health of the developing fetus.

While streptococci do not pose a major threat to a pregnant woman, they can be very dangerous for the baby. A newborn’s immune system is not sufficiently formed to defend itself against streptococci. The risk of a child being infected by a mother streptococcus carrier is very high and amounts to even 70%.

Streptococcal infection can cause sepsis, pneumonia, meningitis, and osteomyelitis in a child.

If streptococcus is found in a pregnant woman, the doctor usually decides about antibiotic therapy. Antibiotics are an effective method of preventing transmission of streptococcus from mother to child during labor. The antibiotic that is given to pregnant women is penicillin. If a woman cannot take penicillin, another antibiotic should be used, of course after consulting a doctor.

Unfortunately, in Poland, vaginal culture testing in pregnant women is not included in the list of obligatory tests. Of course, the doctor can order such a test, or it can be performed in a private laboratory. This test is best done between the 33rd and 37th week of pregnancy.

Do you want to know more about the diagnosis of bacteria in the urine of pregnant women? Read: Bacteria in urine during pregnancy – diagnosis, complications

Streptococcus and its complications

Streptococcus treated with an antibiotic should not cause complications. However, if a streptococcal infection is not treated, very serious complications can occur. Complications are caused by the fact that streptococcus bacteria multiply faster and faster and begin to spread throughout the body. The most common complications of streptococcus are glomerulonephritis, rheumatic fever and toxic shock.

Glomerulonephritis develops because the kidneys build up immune complexes. The immune complexes are antibodies and antigens of streptococcus that protect the body against bacteria. With rheumatic fever, immune complexes build up in the heart muscle. If the streptococcal infection is significantly prolonged, toxic shock, i.e. septic shock, may occur. Septic shock is the result of the accumulation of toxins produced by streptococcus in the human body.

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Streptococcus – how to avoid infection?

Preventive measures and prevention of streptococcal infection are extremely important. To prevent infections, take care of the body’s immunity. Therefore, it is worth enriching your diet with products with vitamin C. You should also take care of personal hygiene and always wash fruits and vegetables before consumption.

Infection by specific species of streptococcus can also be prevented, such as pneumococci. An anti-pneumococcal vaccine protects against pneumococci. Vaccinations can be performed already in infants. The vaccine is also available for older children and adults. The advantage of vaccination is that even if an infection does occur, it will be much milder and in many cases the patient will be able to avoid hospitalization.

What should I know about vaccinations? Check: Vaccinations – types, compulsory vaccinations, adverse vaccination reactions

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