What are Group C Streptococci. How do they differ from other streptococcal groups. What infections can Group C Streptococci cause. How is Group C Streptococcal cellulitis diagnosed and treated. What are the risk factors for Group C Streptococcal infections. How can Group C Streptococcal infections be prevented. What is the prognosis for patients with Group C Streptococcal cellulitis.

Understanding Streptococcal Bacteria: An Overview of Different Groups

Streptococcus is a diverse genus of bacteria that encompasses various groups, each with unique characteristics and potential health implications. To fully grasp the significance of Group C Streptococci, it’s essential to understand the broader context of streptococcal bacteria.

Group A Streptococci (GAS)

Group A Streptococci, scientifically known as Streptococcus pyogenes, are perhaps the most well-known among the streptococcal groups. These bacteria are primarily associated with:

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

GAS infections are highly contagious and can spread through respiratory droplets or direct contact with infected individuals.

Group B Streptococci (GBS)

Group B Streptococci, or Streptococcus agalactiae, are particularly concerning for certain vulnerable populations. These bacteria are known for causing:

• Neonatal infections
• Meningitis in newborns
• Urinary tract infections in adults
• Pregnancy-related complications

Routine screening of pregnant women for GBS has significantly reduced the incidence of neonatal infections in many countries.

Group D Streptococci

Group D Streptococci, including Enterococcus faecalis, are typically part of the normal gut flora. However, they can cause infections when they spread to other parts of the body, such as:

• Urinary tract infections
• Endocarditis
• Bacteremia

These bacteria are often associated with healthcare-associated infections and can be particularly challenging to treat due to antibiotic resistance.

Streptococcus pneumoniae

While not classified under a specific lettered group, Streptococcus pneumoniae is a significant pathogen responsible for:

• Pneumococcal pneumonia
• Meningitis
• Otitis media
• Sinusitis

Vaccination against S. pneumoniae has been instrumental in reducing the incidence of invasive pneumococcal disease, especially in children and the elderly.

Group C Streptococci: The Lesser-Known Bacterial Group

Group C Streptococci (GCS) represent a less common but increasingly significant group of streptococcal bacteria. Unlike their more infamous counterparts in Groups A and B, GCS have been traditionally associated with animal infections. However, their role in human pathology is gaining recognition in the medical community.

Characteristics of Group C Streptococci

Group C Streptococci encompass several species, including:

• Streptococcus dysgalactiae subsp. equisimilis (SDSE)
• Streptococcus equi
• Streptococcus zooepidemicus

These bacteria share some virulence factors with Group A Streptococci, which partly explains their potential to cause similar infections in humans.

Epidemiology of Group C Streptococcal Infections

The incidence of human infections caused by Group C Streptococci has been increasing in recent years. This trend is particularly notable for SDSE, which has emerged as an important human pathogen. Factors contributing to this rise include:

• Improved diagnostic techniques
• Increased awareness among healthcare providers
• Potential changes in the bacteria’s virulence
• Shifts in human population demographics and behaviors

Understanding the epidemiology of GCS infections is crucial for developing effective prevention and treatment strategies.

Clinical Manifestations of Group C Streptococcal Infections

Group C Streptococci can cause a wide range of infections, from mild to severe. The clinical presentations often mimic those caused by Group A Streptococci, which can lead to diagnostic challenges.

Pharyngitis and Upper Respiratory Tract Infections

While the role of GCS in pharyngitis remains somewhat controversial, evidence suggests that these bacteria can cause throat infections. Symptoms may include:

• Sore throat
• Fever
• Difficulty swallowing
• Swollen lymph nodes

The controversy stems from the fact that GCS can also be found in the throats of asymptomatic individuals, making it challenging to establish a clear causal relationship in all cases.

Skin and Soft Tissue Infections

Group C Streptococci are increasingly recognized as causative agents in skin and soft tissue infections. These can range from mild cellulitis to more severe conditions such as:

• Necrotizing fasciitis
• Myositis
• Abscesses

The clinical presentation of GCS skin infections can be similar to those caused by other bacterial pathogens, highlighting the importance of accurate microbiological diagnosis.

Invasive Infections

In some cases, Group C Streptococci can cause invasive infections, leading to serious and potentially life-threatening conditions such as:

• Bacteremia
• Endocarditis
• Meningitis
• Septic arthritis

These invasive infections are more likely to occur in individuals with underlying health conditions or compromised immune systems.

Group C Streptococcal Cellulitis: A Closer Look

Cellulitis caused by Group C Streptococci represents a significant subset of skin and soft tissue infections attributed to these bacteria. Understanding the specific characteristics of GCS cellulitis is crucial for proper diagnosis and management.

Clinical Features of Group C Streptococcal Cellulitis

Group C Streptococcal cellulitis typically presents with the following symptoms:

• Redness and swelling of the affected area
• Warmth and tenderness to touch
• Fever and chills
• Rapid spread of the infection
• Potential for systemic symptoms in severe cases

The infection often begins at a site of skin breakdown, such as a cut, abrasion, or surgical wound. In some cases, no obvious point of entry may be identified.

Diagnostic Challenges

Diagnosing Group C Streptococcal cellulitis can be challenging due to its similarity to cellulitis caused by other pathogens. Key diagnostic steps include:

1. Clinical examination and history taking
2. Blood cultures in cases of suspected bacteremia
3. Tissue cultures from the affected area, when possible
4. Advanced molecular techniques for precise bacterial identification

It’s important to note that routine throat swabs or skin surface cultures may not always detect the presence of Group C Streptococci, especially in deeper tissue infections.

Treatment Approaches for Group C Streptococcal Infections

The treatment of Group C Streptococcal infections, including cellulitis, typically involves a combination of antimicrobial therapy and supportive care. The specific approach depends on the severity and location of the infection.

Antibiotic Therapy

Group C Streptococci are generally susceptible to a range of antibiotics. Common treatment options include:

• Beta-lactam antibiotics (e.g., penicillin, amoxicillin)
• Cephalosporins
• Macrolides (for penicillin-allergic patients)
• Clindamycin (particularly effective against toxin-producing strains)

The choice of antibiotic may be influenced by local resistance patterns and the patient’s individual risk factors.

Duration and Route of Administration

The duration and route of antibiotic administration depend on the severity of the infection:

• Mild to moderate cellulitis: Oral antibiotics for 7-14 days
• Severe or rapidly progressing infections: Intravenous antibiotics, potentially followed by oral therapy
• Invasive infections: Prolonged intravenous antibiotic courses, often lasting several weeks

Close monitoring of the patient’s response to treatment is essential, with adjustments made as necessary based on clinical improvement and laboratory findings.

Adjunctive Therapies

In addition to antibiotics, management of Group C Streptococcal cellulitis may include:

• Elevation of the affected limb to reduce swelling
• Pain management
• Proper wound care and dressing changes
• Surgical intervention in cases of abscess formation or necrotizing infections

Addressing any underlying conditions that may have predisposed the patient to infection is also crucial for comprehensive management.

Prevention and Public Health Implications

While Group C Streptococcal infections are less common than those caused by Group A or B Streptococci, their increasing incidence underscores the importance of prevention strategies and public health awareness.

Risk Factors and Prevention Strategies

Identifying and mitigating risk factors for Group C Streptococcal infections is key to prevention. Common risk factors include:

• Close contact with animals, particularly horses and cattle
• Compromised skin integrity
• Chronic medical conditions (e.g., diabetes, immunosuppression)
• Advanced age

Prevention strategies focus on:

1. Proper hand hygiene and wound care
2. Appropriate personal protective equipment when working with animals
3. Management of underlying health conditions
4. Prompt treatment of minor skin injuries

Surveillance and Reporting

Improved surveillance of Group C Streptococcal infections is crucial for understanding their epidemiology and guiding public health interventions. This includes:

• Accurate identification and reporting of cases
• Monitoring of antibiotic resistance patterns
• Investigation of potential outbreaks
• Collaboration between human and veterinary health sectors

Enhanced surveillance can lead to early detection of emerging trends and inform targeted prevention efforts.

Future Directions in Group C Streptococcal Research

As our understanding of Group C Streptococci evolves, several areas of research hold promise for improving diagnosis, treatment, and prevention of these infections.

Molecular Epidemiology

Advanced molecular techniques are shedding light on the genetic diversity and evolution of Group C Streptococci. This research aims to:

• Identify virulence factors specific to GCS
• Track the spread of particularly pathogenic strains
• Understand the genetic basis for antibiotic resistance

These insights could lead to more targeted therapeutic approaches and improved diagnostic tools.

Vaccine Development

While vaccines exist for some streptococcal species, there is currently no vaccine specifically targeting Group C Streptococci. Research in this area focuses on:

• Identifying potential vaccine candidates
• Evaluating cross-protection with existing streptococcal vaccines
• Assessing the feasibility and cost-effectiveness of GCS vaccination programs

A successful vaccine could significantly reduce the burden of GCS infections, particularly in high-risk populations.

Novel Therapeutic Approaches

Ongoing research is exploring innovative treatment strategies for Group C Streptococcal infections, including:

• Bacteriophage therapy
• Antimicrobial peptides
• Immunomodulatory therapies
• Combination therapies targeting virulence factors

These approaches may offer alternatives to traditional antibiotics, potentially addressing concerns about antimicrobial resistance.

In conclusion, Group C Streptococcal infections, including cellulitis, represent an evolving challenge in infectious diseases. As our understanding of these bacteria grows, so does our ability to diagnose, treat, and prevent the infections they cause. Continued research and vigilance are essential to stay ahead of this emerging pathogen and ensure optimal patient outcomes.

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.