What are the different types of streptococci bacteria. How does Group C streptococci cause infections. Why is Group C streptococcal cellulitis a concern for healthcare professionals. What treatment options are available for Group C strep infections.

Types of Streptococci Bacteria: A Comprehensive Overview

Streptococcus is a diverse class of bacteria that includes both beneficial and pathogenic organisms. While some streptococci are part of the normal human microbiome, others can cause serious infections. The most clinically significant groups are A, B, C, D, and G. Let’s explore each type in detail:

Group A Streptococci (GAS)

Group A streptococci, scientifically known as Streptococcus pyogenes, are the most well-known among the streptococcal groups. They are primarily associated with:

• Strep throat (streptococcal pharyngitis)
• Tonsillitis
• Skin infections
• More severe conditions like necrotizing fasciitis

GAS can also lead to post-infection complications such as rheumatic fever and glomerulonephritis, making prompt treatment crucial.

Group B Streptococci (GBS)

Streptococcus agalactiae, or Group B strep, is particularly concerning for specific populations:

• Pregnant women
• Newborns
• Elderly individuals

GBS can cause severe infections in newborns, including sepsis, pneumonia, and meningitis. In adults, it may lead to urinary tract infections, skin infections, and bloodstream infections.

Group D Streptococci

Enterococcus faecalis is the most common species in this group. While typically harmless as part of the intestinal flora, Group D strep can cause infections when it enters other parts of the body. Urinary tract infections are the most frequent manifestation of Group D streptococcal infections.

Streptococcus pneumoniae

This distinct species, often referred to as pneumococcus, is a leading cause of:

• Pneumonia
• Meningitis
• Otitis media (ear infections)
• Sinusitis

S. pneumoniae colonizes the upper respiratory tract but can become pathogenic under certain conditions.

Groups C and G Streptococci

These groups are less common but are gaining attention due to their increasing prevalence in certain infections. Streptococcus dysgalactiae subsp. equisimilis (SDSE) is a notable species within these groups, sharing similarities with Group A strep.

The Enigma of Group C Streptococci: Unraveling Its Role in Infections

Group C streptococci have long been overshadowed by their more infamous cousins, Groups A and B. However, recent research has shed light on their potential to cause various infections. Are Group C strep infections truly a cause for concern? The answer is increasingly pointing towards yes.

Pharyngitis: A Controversial Connection

The role of Group C strep in pharyngitis remains a topic of debate in the medical community. While these bacteria have been isolated from throat cultures of individuals with sore throats, they’re also found in asymptomatic carriers. This raises an important question: Is Group C strep a true pathogen or merely an innocent bystander?

Recent studies suggest that Group C strep may indeed play a causative role in some cases of pharyngitis. The prevalence of these bacteria is higher in symptomatic individuals compared to healthy controls. Additionally, the genetic similarity between Group C and the well-established pharyngitis-causing Group A strep lends credence to its pathogenic potential.

Bacteremia: A Serious Concern

While the jury is still out on pharyngitis, the link between Group C strep and bacteremia is much clearer. Bacteremia, the presence of bacteria in the bloodstream, is a potentially life-threatening condition that requires immediate medical attention. Certain strains of Group C strep have been strongly associated with bacteremia, particularly in individuals with underlying health conditions.

Group C Streptococcal Cellulitis: A Deep-Seated Threat

Cellulitis is a common bacterial skin infection that affects the deeper layers of skin and underlying tissue. While various bacteria can cause cellulitis, Group C strep has emerged as a notable culprit, particularly in cases that prove challenging to treat.

Understanding the Pathogenesis

Group C streptococcal cellulitis often develops following a breach in the skin barrier. This can occur through:

• Cuts or abrasions
• Insect bites
• Surgical wounds
• Pre-existing skin conditions

Once the bacteria penetrate the skin, they can multiply rapidly, causing inflammation and tissue damage. The infection can spread to deeper layers, leading to more severe complications if left untreated.

Recognizing the Symptoms

Group C streptococcal cellulitis typically presents with the following symptoms:

• Redness and swelling of the affected area
• Warmth and tenderness to touch
• Pain or discomfort
• Fever and chills
• Swollen lymph nodes

In severe cases, the infection may lead to the formation of abscesses or spread to the bloodstream, causing sepsis.

Diagnostic Challenges in Group C Streptococcal Infections

Accurately diagnosing Group C streptococcal infections can be challenging due to their similarity to other bacterial infections. How can healthcare providers ensure a correct diagnosis? The key lies in a combination of clinical assessment and laboratory testing.

Clinical Evaluation

A thorough physical examination is crucial for identifying signs of infection. For cellulitis, healthcare providers will assess the affected area for characteristic symptoms such as redness, swelling, and warmth. They will also inquire about recent injuries or potential exposure to the bacteria.

Laboratory Testing

Definitive diagnosis often requires laboratory confirmation. This may include:

• Blood cultures to detect bacteremia
• Wound cultures for cellulitis cases
• Throat swabs for suspected pharyngitis

Rapid antigen detection tests, while useful for Group A strep, are not typically available for Group C strep. Therefore, culture-based methods remain the gold standard for diagnosis.

Treatment Approaches for Group C Streptococcal Infections

Once a diagnosis of Group C streptococcal infection is confirmed, prompt and appropriate treatment is essential. What are the most effective treatment strategies for these infections?

Antibiotic Therapy

Antibiotics form the cornerstone of treatment for Group C strep infections. The choice of antibiotic depends on several factors:

• Severity of the infection
• Location of the infection
• Patient’s age and overall health
• Local antibiotic resistance patterns

Commonly prescribed antibiotics for Group C strep infections include:

• Penicillin or ampicillin
• Cephalosporins
• Vancomycin (for severe cases or penicillin-allergic patients)

Supportive Care

In addition to antibiotics, supportive measures play a crucial role in managing Group C strep infections:

• Pain management with over-the-counter analgesics
• Proper wound care for cellulitis cases
• Adequate hydration and rest
• Elevation of affected limbs to reduce swelling

Monitoring and Follow-up

Close monitoring is essential to ensure the infection is responding to treatment. Patients may require follow-up appointments to assess progress and adjust treatment if necessary.

Prevention Strategies: Minimizing the Risk of Group C Strep Infections

While Group C streptococcal infections can be serious, there are steps individuals can take to reduce their risk. What are the most effective prevention strategies?

Good Hygiene Practices

Maintaining proper hygiene is crucial in preventing the spread of streptococcal bacteria:

• Regular handwashing with soap and water
• Covering mouth and nose when coughing or sneezing
• Avoiding close contact with infected individuals

Wound Care

Proper wound care can significantly reduce the risk of cellulitis:

• Clean all cuts, scrapes, and wounds promptly
• Apply an antibiotic ointment to minor wounds
• Cover wounds with clean, dry bandages
• Seek medical attention for deep or contaminated wounds

Maintaining Overall Health

A strong immune system can help ward off streptococcal infections:

• Eating a balanced diet rich in fruits and vegetables
• Getting adequate sleep
• Managing stress levels
• Staying up-to-date with vaccinations

The Future of Group C Streptococcal Research: Emerging Trends and Challenges

As our understanding of Group C streptococci continues to evolve, researchers are focusing on several key areas to improve diagnosis, treatment, and prevention of these infections. What are the most promising avenues of research?

Genomic Studies

Advances in genomic sequencing are providing valuable insights into the genetic makeup of Group C strep. This research could lead to:

• Improved diagnostic tools
• Identification of virulence factors
• Development of targeted therapies

Vaccine Development

While vaccines exist for some streptococcal species (like S. pneumoniae), there is currently no vaccine for Group C strep. Researchers are exploring potential vaccine candidates that could provide protection against multiple streptococcal groups.

Antibiotic Resistance Monitoring

As with many bacterial pathogens, antibiotic resistance is a growing concern for Group C strep. Ongoing surveillance and research into alternative treatments are crucial to maintaining effective treatment options.

Epidemiological Studies

Continued epidemiological research is essential to understand the changing patterns of Group C strep infections. This includes:

• Monitoring infection rates in different populations
• Identifying risk factors for severe infections
• Tracking the emergence of new strains

As research progresses, our ability to prevent, diagnose, and treat Group C streptococcal infections will undoubtedly improve. Healthcare providers and patients alike should stay informed about these developments to ensure the best possible outcomes in managing these challenging infections.

What Is Group C Streptococci?

Content

• Overview
• What are the types of streptococci?
• What infections are caused by group C streptococci?
• Does strep group C need to be treated?
• The lowdown
• FAQs

Nearly everyone has heard of strep throat and the bacteria that causes it—streptococci. But did you know that there are different types of streptococci bacteria, or they can cause other types of infection too? Group C is one of the more elusive forms of streptococci and among two strains we know little about.

In this post, we’ll explain what you need to know about group C streptococci.

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Streptococcus¹ is an entire class of organisms. Many of these bacteria play an important role in both animals and humans. Several of them, however, cause illnesses that need medical treatment. The most well-known of these medically significant groups of streptococci are groups A, B, and D, with groups C and G causing less common illnesses. Below is a breakdown of each of these types of streptococci bacteria.

Group A

Also known as streptococcus pyogenes, group A streptococci are most commonly associated with pharyngitis and tonsillitis. Streptococcal pharyngitis is the medical term for strep throat. Although other forms of streptococci can lead to the condition, group A is the most common culprit.

This group can also be responsible for sinusitis, otitis, mastoiditis, pneumonia with empyema, joint or bone infections, necrotizing fasciitis or myositis, meningitis, and endocarditis.

Group B

This group of streptococci, otherwise known as streptococcus agalactiae², is most commonly associated with neonatal infections. Its effect on susceptible populations, such as pregnant women, newborns, and the elderly, remains a high source of mortality in those groups.

While group A is commonly associated with pharyngitis, group B more commonly manifests as meningitis, neonatal sepsis, pneumonia in infants and vaginitis, puerperal fever, urinary tract infection, or skin infection in adults.

Group D

An example of streptococci that are a normal part of the microbial flora in the human body is enterococcus faecalis³, or group D streptococci. This type of bacteria normally lives in your intestines, where they pose no threat.

However, when the bacteria make their way to other parts of the body, they can cause serious infections. The most common form of infection caused by group D streptococci is urinary tract infection.

Streptococcus pneumoniae

As the name implies, streptococcus pneumoniae is most commonly associated with pneumococcal pneumonia. It can also cause meningitis and occult bacteremia. Like group D streptococci, S. pneumoniae is a normal part of the microbial flora in the body.

This type is normally present in the respiratory tract. However, infection from the outside can cause pneumonia and other bacterial infections.

Groups C and G

Streptococci groups C and G are rarer than the other types. The most common type is streptococcus anginosus, though one form of them — the streptococcus dysgalactiae subsp. equisimilis (SDSE) — is becoming more common. This strain of bacteria is similar to the group A Streptococcus. pyogenes, commonly associated with throat, skin, and soft tissue infections.

Although the relation of group C and G streptococci to skin and soft tissue infections is clear, there is some doubt about their role in throat infections. While the bacteria have shown up in cultures of people with pharyngitis, they also show up in the throats of healthy people.

Group C streptococci can cause a variety of infections, including the following:

Pharyngitis

Pharyngitis is a type of sore throat caused by a bacterial infection. Infection from streptococci bacteria is typically referred to as strep throat.

Pharyngitis⁴ is associated with a sudden onset of sore throat, high fever, and pain when swallowing. As a bacterial infection, it’s typically spread through direct person-to-person contact.

As mentioned earlier, the exact role of group C streptococci in pharyngitis remains controversial. Although group G has been clearly linked⁵ to outbreaks of pharyngitis, the virulence of group C in human pharyngitis remains unclear.

While studies have shown the bacteria to be present in healthy people and people with pharyngitis, they are found at a higher rate in those with the illness than in the control group. The bacteria’s similarity to group A lends further evidence to its role in virulence.

Bacteremia

Certain streptococci bacteria in group C are highly associated with bacteremia⁶. This is a dangerous condition that refers to an infection of bacteria in the blood. Bacteremia requires the urgent administration of antibiotics, as a delay in treatment increases the mortality risk of people with it.

People most susceptible to bacteremia infection from group C streptococci are those who already have certain underlying conditions. Depending on the series of bacteria, up to 70% of patients have malignancy, cardiovascular disease, diabetes mellitus, or immunosuppression.

Maternal and neonatal infections

Several types of group C streptococci bacteria can be found as a normal part of a woman’s genitourinary flora. Despite this, the bacteria has been attributed to several outbreaks of puerperal fever.

Also known as postpartum infection⁷, puerperal fever caused by group C streptococci is rare. The known incidents were believed to have been caused by environmental factors because the bacteria was traced back to a toilet seat and a bathtub plug.

Infection in infants is also rare. There have been a few cases of meningitis in newborns caused by group C streptococci, but infections of this sort are not common.

Infections of the skin and soft tissue

Many skin and soft tissue infections can be caused by group C streptococci, including pyoderma, cellulitis, erysipelas, surgical wound infections, abscesses, necrotizing soft tissue infections, and pyomyositis. Among these, cellulitis and erysipelas are particularly common, with group C being responsible in equal or greater frequency than group A.

Group C streptococci can also cause more serious skin infections. These infections include necrotizing fasciitis, Fournier’s gangrene, and necrotizing myositis. Here, the dangers of group C clearly outweigh those of group A. Group C is associated with a 33% mortality rate compared to only 11% for group A. These more dangerous infections typically occur in older people with comorbidities.

Streptococcal arthritis

Bacteria in the streptococci family can also cause an infection in the joints, which results in infectious arthritis. More specifically, streptococcal arthritis. According to the John Hopkins Arthritis Center⁵, streptococcal arthritis goes away when the underlying infection that’s causing it clears up. Although this usually happens within 3–12 months, it can last longer for most.

A group of hospitals in France published the occurrence of various streptococci strains in infectious arthritis patients. SDSE was found in 12% of patients and S. anginosus in 11%. These incident rates were second only to the group B type S. agalactiae.

As we’ve seen, several members of group C streptococci are normal parts of the human microbial flora. So their presence does not mean a course of treatment must be pursued. However, treatment is recommended if the bacteria has caused an infectious illness.

The typical treatment for group C streptococci is the antibiotic penicillin. The need for treatment grows more urgent when the bacteria is causing life-threatening conditions, such as bacteremia or one of the deadly skin infections.

Although less common as a cause of illness than some other groups, infection with strep group C can cause various adverse medical conditions. Some of these conditions can be life-threatening, particularly in older or immunocompromised patients. Group C infections can be treated with prescription antibiotics, most commonly penicillin.

If you believe you may have one of the conditions described above, make an appointment with your doctor. They’ll be able to help determine the cause of your illness and which, if any, strep groups are playing a role in it.

Is strep C serious?

Strep group C can cause a range of different illnesses. Some of the infections that the group can cause are quite serious. These include infection of the blood, known as bacteremia, and several skin infections that can be deadly. If you aren’t feeling well, it’s always best to see a doctor to rule out serious illness.

Is strep group C contagious?

Yes. Strep group C can spread from person to person as a bacterial infection. Although most forms of group C are spread this way, it’s also possible for the bacteria to spread to humans through animal contact, such as contaminated meat products.

What does C mean on a strep test?

Streptococci bacteria can be split into several groupings. The groupings are differentiated by letter. If you see the letter C on a strep test, the bacteria causing your infection comes from streptococci in group C.

The Different Types of Streptococci (Strep Bacteria)

Although strep throat is a common form of infection from streptococcal bacteria, it is not the only kind. Streptococcal infections are any type of infection caused by the streptococcal, or “strep” group of bacteria.

There are a number of different streptococci, which create symptoms ranging from a mild throat infection to a life-threatening infection of the blood or organs. Anyone can be affected, from babies and small children to older adults.

Most strep infections can be treated with antibiotics.

Streptococci infections are divided into several groups: Group A streptococcus, Group B streptococcus, Group C streptococcus, and Group G streptococcus.

Group A Streptococcus

Group A strep, sometimes called GAS, tends to affect the throat and the skin. People may carry GAS in these areas yet not show any symptoms of illness. Most group A strep infections cause relatively mild illness, but on rare occasions, these bacteria can lead to severe and even life-threatening disease.

Group A strep infections spread through direct contact with mucus from the nose or throat of infected persons or through contact with infected wounds or sores. (1) Illnesses from group A strep infection include:

Strep Throat In general, strep throat is a mild illness, but it can be very painful. Symptoms include sore throat that comes on very quickly, pain when swallowing, fever, red and swollen tonsils (sometimes with white patches or streaks of pus), small red spots on the roof of the mouth, and swollen lymph nodes in the front of the neck. Strep throat may also be accompanied by headache, abdominal pain, nausea, or vomiting, especially in children. Illness typically manifests two to five days after exposure.

A doctor cannot tell if someone has strep throat just by looking, so a diagnostic test is needed. A rapid strep test involves swabbing the throat and running a lab test to see if GAS is the cause of the illness.

While most sore throats are caused by viruses, strep throat is caused by bacteria and therefore can only be treated with antibiotics.

While anyone can get strep throat, it’s more common among school-aged children 5 through 15. Parents and adults who are often in contact with children of these ages are more likely to get strep throat than adults who are not. (2)

Scarlet Fever Also referred to as scarlatina, scarlet fever is a relatively mild illness characterized by a very red sore throat, a red rash that has a sandpaper feel, and a “strawberry,” or red and bumpy, tongue. Other symptoms can include fever, swollen glands in the neck, whitish coating on the tongue, and bright red skin in the underarm, elbow, or groin.

The illness typically begins with a fever and sore throat. The rash — caused by a toxin made by group A strep bacteria — usually appears a day or two later, although it can begin before the illness or up to seven days later.

Scarlet fever is highly contagious. It can be spread from person to person when someone who is infected coughs or sneezes: the bacteria travels in small droplets in the air. You can get sick by breathing in those droplets or by touching something that the droplets have landed on and touching your nose or mouth. Drinking from the same glass or eating from the same plate as an infected person can also spread the illness. It is also possible to get scarlet fever sores on the skin caused by GAS.

Scarlet fever is treated with a course of antibiotics. Complications sometimes occur and can include abscesses around the tonsils, swollen lymph nodes in the neck, and sinus and ear infections. Other, more rare complications can affect the heart, including rheumatic fever and kidney disease.

Like strep throat, scarlet fever is more common in children than adults, particularly those ages 5 through 15. Close contact with someone who has the infection is the biggest risk factor for getting the illness. There is no vaccine for scarlet fever, but people can protect themselves by practicing good hygiene, including using a tissue to cover your mouth when sneezing or coughing, washing hands frequently, using alcohol-based hand sanitizer if soap and water are unavailable, and coughing or sneezing into your upper sleeve or elbow rather than your hands if a tissue is not available. (3)

Impetigo This is an infection of the top layers of skin that typically starts when bacteria gets into a cut, scratch, or insect bite. It is usually caused by the bacteria Staphylococcus aureus but can also be caused by group A strep. It is most common among children ages 2 to 6.

Symptoms begin as itchy red or pimple-like sores surrounded by red skin, usually on the face, arms, or legs, that are filled with pus. Impetigo is contagious and can be spread by contact with sores or nasal discharge of an infected person. It can be treated with a round of antibiotics. (4)

Post-Streptococcal Glomerulonephritis Also referred to as PSGN, this is a kidney disease that can develop after a GAS infection — but PSGN is not a GAS infection of the kidneys. It’s a result of the body’s immune system fighting off the group A strep infection. PSGN usually occurs 10 days after strep throat or scarlet fever and about three weeks after a GAS skin infection.

Symptoms of PSGN include dark, reddish-brown urine, swelling in the face, hands and feet, decreased amount of urine or decreased need to urinate, and fatigue.

The condition is treated by managing symptoms, including limiting salt and water intake or prescribing medication to reduce swelling. Antibiotics can also help kill any strep A bacteria left in the body.

Most people with PSGN recover within a few weeks, but in rare instances long-term kidney damage, including kidney failure, can occur. (5)

Group B Streptococcus

Group B streptococcus, also known as group B strep or GBS, is a type of bacteria that can cause illness in people of all ages, though it can be particularly severe in newborns, most commonly causing sepsis, pneumonia, and meningitis. In adults, the most common health issues caused by GBS include urinary tract infections, skin infections, bloodstream infections, pneumonia, skin and soft-tissue infections, and bone and joint infections.

In babies, group B strep infections occur as either early-onset or late-onset. Early-onset occurs in babies younger than 1 week old, and the infection is most often passed from mother to baby during labor. Symptoms of GBS infection in newborn babies usually develop within the first few hours or days of giving birth and include being floppy or unresponsive, poor feeding, grunting when breathing, and unusually fast or slow breathing and heartbeat.

Antibiotics given to the mother during labor can help prevent the spread of the infection to the baby.

Late-onset group B strep infection in babies can occur at 1 week through 3 months old. A GBS infection is sometimes passed from mother to baby, but it can also come from another source.

Early-onset used to be the most common type of group B strep infection in newborns, but because of prevention efforts, both early-onset and late-onset occur at similar low rates, according to the Centers for Disease Control and Prevention (CDC).

In adults, group B strep infection occurs less frequently than in babies, but it can affect anyone. The sources of disease caused by GBS in adults are unknown, but the bacteria are present in both the gastrointestinal and genitourinary tracts, and may be the source of infection.

If the infection leads to sepsis or pneumonia, it can be fatal. On average, 1 in 20 nonpregnant adults with an invasive strep B infection dies, the CDC reports. The chance of GBS infection increases with age. Younger adults who do not have any other medical conditions have a lower risk of death from GBS. (6)

Group C and G Streptococci

Group C and G streptococci are much less understood than strep A and B because the diseases caused by these bacteria are far less common.

Group C and G strep most commonly live in animals such as horses and cattle and can spread to humans through raw milk or contact with these animals. The bacteria can also live in people’s throats and on human skin, particularly in areas damaged by conditions like eczema or on mucous surfaces, such as the vagina or bowel.

Infections can be treated with antibiotics, but severe infections can be fatal, especially when they have entered the bloodstream. (7)

Resources We Love

1. Centers for Disease Control and Prevention
2. Mayo Clinic
3. Cleveland Clinic
4. Familydoctors.org

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Confirmation of infection with B-hemolytic streptococcus group A (St. Pyogenes)

Comprehensive study aimed at the detection and confirmation of infection with B-hemolytic streptococcus group A (Streptococcus pyogenes).

Synonyms Russian

Pyogenic streptococcus, group A beta-hemolytic streptococcus; bacteriological culture; RT-PCR [real-time polymerase chain reaction]; comprehensive examination.

Synonyms English

Streptococcus pyogenes, group A streptococcus; bacteria identification; RT-PCR [polymerase chain reaction, real-time PCR]; comprehensive examination.

What biomaterial can be used for research?

Throat swab (oropharynx).

How to properly prepare for an examination?

• Do not eat, drink, brush your teeth, gargle your mouth/throat, chew gum, or smoke 3-4 hours before taking oral oropharyngeal (pharyngeal) swabs. 3-4 hours before taking swabs from the nose, do not instill drops / sprays and do not rinse the nose. Taking smears is best done in the morning, immediately after a night’s sleep.

General information about the study

Beta (β)-hemolytic streptococcus group A (pyogenic streptococcus, S. pyogenes) is a gram-positive immotile bacterium with hemolytic activity, that is, the ability to cause the destruction of red blood cells. The pathogenetic effect of the microorganism is associated with the possibility of producing toxins: hemolysin, streptolysin, streptokinase A and B, hyaluronidase, deoxyribonuclease. The infection caused by S. pyogenes is transmitted mainly by airborne, contact and food transmission routes.

Infection with this pathogen can lead to the development of a wide range of diseases, such as tonsillitis, pharyngitis, tonsillopharyngitis (angina), otitis media, acute rheumatic fever, rheumatic heart disease, pneumonia, acute glomerulonephritis, myocarditis, endocarditis, erysipelas, streptoderma, osteomyelitis, cellulitis, sepsis, septic arthritis.

Diagnosis of infection with S. pyogenes group A is based on clinical, anamnestic data, the results of changes in the clinical analysis of blood and confirmed by laboratory methods. In clinical laboratory diagnostics, several methods are used: a bacteriological method to detect the growth of colonies of a microorganism; polymerase chain reaction (PCR) method – to identify the genetic material of the pathogen.

Bacteriological examination is the inoculation of the obtained biomaterial on specific diagnostic nutrient media. It is the first stage of diagnostics, it is used to confirm the diagnosis of “streptococcal infection”, it allows to identify pathogens only in the early stages of the disease, it is also used to evaluate the effectiveness of antibiotic therapy against the pathogen S. pyogenes. The result of this examination can be assessed only a few days after sowing, which may delay the timely establishment of the correct diagnosis and the appointment of adequate therapy.

Real-time polymerase chain reaction (RT-PCR) is one of the modern methods of molecular diagnostics. It allows you to identify the DNA of the pathogen S. pyogenes of group A, and not other related streptococci, which are representatives of the normal microflora of the oropharynx (S. mutans, S. viridians). The RT-PCR method has a high diagnostic sensitivity (theoretically, only 1 DNA molecule is enough to carry out this reaction) and high diagnostic specificity, which is not inferior to other methods for diagnosing this microorganism. It should be noted that, unlike other laboratory methods, RT-PCR is effective during treatment with antibacterial drugs. But this method cannot be used to control the treatment, since the result of the analysis will remain positive (false positive) for some time after the start of treatment, even if it is effective. The RT-PCR method is important in the examination of “healthy carriers” of streptococcus. Asymptomatic carriage of S. pyogenes group A should be suspected in a patient with streptococcus after an adequate course of antibiotic therapy, as well as in family members of a patient with frequent exacerbations of streptococcal pharyngitis.

What is research used for?

• For comprehensive laboratory diagnosis of infection with S. pyogenes group A.
• To confirm the diagnosis of streptococcal infection.
• For the differential diagnosis (along with other studies) of diseases that occur with similar symptoms.
• To evaluate the effectiveness of ongoing antibiotic therapy against the pathogen S. pyogenes group A.
• For rapid, within a few hours, diagnosis of infectious diseases caused by S. pyogenes and their complications.
• For the diagnosis of asymptomatic carriage of S. pyogenes.

When is the test ordered?

• With symptoms of acute pharyngitis, tonsillitis, tonsillopharyngitis: fever, pain when swallowing, swelling and erythema of the pharyngeal mucosa, purulent discharge from the surface of the tonsils, painful regional lymphadenitis.
• If you suspect the development of complications caused by infection with S. pyogenes group A: otitis media, acute rheumatic fever, rheumatic heart disease, pneumonia, acute glomerulonephritis, myocarditis, endocarditis, erysipelas, streptoderma, osteomyelitis, cellulitis, sepsis, septic arthritis.
• When examining a patient with recurrent pharyngitis.
• When examining family members of a patient with frequent recurrences of acute streptococcal pharyngitis.
• If a streptococcal infection or asymptomatic carrier is suspected.
• For nosocomial infections.
• When conducting antibiotic therapy for streptococcal infection.
• In some cases, for prophylactic purposes before hospitalization.

What do the results mean?

Reasons for the increase

• Acute streptococcal infection.
• Asymptomatic carrier.
• Acute pharyngitis, tonsillitis, tonsillopharyngitis and/or suspected complications from infection with S. pyogenes group A.

Reason for downgrade

• Absence of streptococcal infection (provided not treated with antibiotics).

Important remarks

• The result of a comprehensive examination is evaluated taking into account anamnestic, clinical and other laboratory data.

Also recommended

• [10-009] Hemolytic Streptococcus A culture
• [09-065] Streptococcus pyogenes, DNA [real-time PCR]
• [02-029] Clinical blood test: complete analysis, leukocyte count, ESR (with blood smear microscopy in case of pathological changes)
• [02-025] Leukocyte formula
• [02-006] Urinalysis with microscopy
• [06-007] Antistreptolysin O
• [06-023] Creatine kinase MB
• [06-076] Troponin I
• [06-050] C-reactive protein, quantitative (highly sensitive method)
• [09-074] Streptococcus pneumoniae, DNA [real-time PCR]
• [10-010] Culture for diphtheria (Corynebacterium diphtheriae)

Who orders the examination?

General practitioner, otolaryngologist, infectious disease specialist, pulmonologist, pediatrician, rheumatologist, epidemiologist, traumatologist.

Literature

1. Chernecky S.S. Laboratory tests and diagnostic procedures / S.S. Chernecky, B.J. Berger; 5th ed. – St. Louis: Saunders Elsevier, 2008. – 1232 p.
2. Fauci, Braunwald, Kasper, Hauser, Longo, Jameson, Loscalzo Harrison’s principles of internal medicine, 17th edition, 2009.
3. McPhee S.J., Papadakis M. CURRENT Medical Diagnosis and Treatment / S. J. McPhee, M. Papadakis; 49 ed. – McGraw-Hill Medical, 2009.
4. Hill HR. Group A streptococcal carrier versus acute infection: the continuing dilemma. Clin Infect Dis. 2010 Feb 15;50(4):491-2.
5. Garcia-Arias M, Balsa A, Mola EM. Best Pract Res Clin Rheumatol. Septic arthritis. 2011 Jun;25(3):407-21.

Culture for group A hemolytic streptococcus

Microbiological examination to detect infection with group A hemolytic streptococcus.

0002 Culture for group A beta-hemolytic streptococcus, culture for pyogenic streptococcus, culture for GABHS.

Synonyms English

Research method

Microbiological method.

What biomaterial can be used for research?

Oropharyngeal swab, nasopharyngeal swab, nasal swab.

How to properly prepare for an examination?

• Do not eat, drink, brush your teeth, gargle your mouth/throat, chew gum, or smoke 3-4 hours before taking oral oropharyngeal (pharyngeal) swabs. 3-4 hours before taking swabs from the nose, do not instill drops / sprays and do not rinse the nose. Taking smears is best done in the morning, immediately after a night’s sleep.

General information about the study

Streptococci are the most common causative agents of bacterial infections in humans. There are different serological groups of streptococci: A, B, C, D, F, G. The most pathogenic for humans are group A streptococci, or pyogenic streptococci.

Bacteria of this group have hemolytic properties (can destroy red blood cells), so they are also called hemolytic streptococci. They are the causative agents of various purulent and immuno-inflammatory diseases, such as tonsillitis, pharyngitis, tonsillitis, scarlet fever, otitis media, acute rheumatic fever and rheumatic heart disease, acute glomerulonephritis, myocarditis, endocarditis, erysipelas, streptoderma, osteomyelitis, otitis media. Culture for group A hemolytic streptococcus is done to detect streptococcal infection and is the gold standard for diagnosing strep pharyngitis.

What is research used for?

• To confirm the diagnosis of streptococcal infection.
• For the differential diagnosis (along with other studies) of diseases that occur with similar symptoms, such as pharyngitis and tonsillitis of various origins, a localized form of diphtheria of the pharynx, paratonsillar abscess, infectious mononucleosis, leukemia, agranulocytosis, acute respiratory infections, oropharyngeal candidiasis, exacerbation of chronic tonsillitis.
• To assess the effectiveness of antibiotic therapy for streptococcal infections.

When is the test ordered?

• When the patient has angina or pharyngitis.
• If streptococcal infection or bacterial carriage is suspected.
• For nosocomial infections.
• When conducting antibiotic therapy for streptococcal infection.
• In some cases, for prophylactic purposes before hospitalization.

What do the results mean?

Reference values: no growth.

Reason for positive result

• Acute streptococcal infection.
• Asymptomatic carrier.

Reason for negative result

• Absence of streptococcal infection (provided no antibiotic treatment was given).

What can influence the result?

Antibacterial therapy.

Also recommended

• Streptococcus pyogenes DNA [real-time PCR]
• Complete blood count (without leukocyte formula and ESR)
• Urinalysis with microscopy
• Creatine kinase MB
• Troponin I
• Culture for diphtheria (Corynebacterium diphtheriae)

Who orders the examination?

Infectionist, therapist, general practitioner, pediatrician, ENT, rheumatologist.