Introduction:
Strep A belongs to group A streptococci bacteria, which resides in the nose and throat. Strep A can cause infections in the throat, tonsils, and other infections like scarlet fever (sore throat with rash), and abscess (infected pus-filled cavities). Strep A tests are performed to diagnose group A streptococcal infections. The symptoms of strep A infections can be mild to severe and deadly if left untreated. A throat culture is the gold standard test to diagnose group A streptococcal infections.
What Is the Prevalence of Strep A Infections?
Pharyngitis (sore throat) due to group A streptococcal infections varies around 15 to 30 percent in children and 5 to 15 percent in adults.
What Is the Incidence of Group A Streptococcal Infections?
The incidence of group A streptococcal infections is around 12,000 to 20,000 cases per year.
Are Strep A Infections Contagious?
Strep A infections with the presenting symptoms are contagious (can spread from one person to another).
What Are the Infections Caused by Group A Streptococci?
Group A streptococcus causes a wide range of infections such as
-
Strep throat (swelling of tonsils and back of the throat).
-
Scarlet fever (rash with a sore throat).
-
Pharyngitis (sore throat).
-
Impetigo (bacterial infection involving skin).
-
Necrotizing fasciitis (skin-eating disease).
-
Cellulitis (infected, red, and swollen skin).
-
Streptococcal toxic shock syndrome (serious infections causing low blood pressure and failure of body organs resulting in death).
-
Rheumatic fever (disease affecting the heart, joints, bones, and skin).
-
Post-streptococcal glomerulonephritis (kidney disease that occurs after streptococcal infections).
Strep A bacteria reside in the normal environment of skin and mucous membranes. It can be spread from the infected person through coughing or sneezing (contact with oral secretions of an infected person) and by direct infections from the bacteria through open wounds.
What Are the Signs and Symptoms of Strep A Infections?
Signs and symptoms of group A streptococcal infections are:
-
Fever.
-
Sore throat.
-
Nausea and vomiting.
-
Headaches.
-
Stomach pain.
-
Throat swelling.
-
Tonsillitis (swelling of the tonsils).
-
Loose motions.
-
Pain in swallowing.
-
Swelling of the lymph nodes of the neck.
What Are Strep A Tests?
Strep A tests are performed to identify group A streptococcal infections (most commonly throat and tonsils infections).
Strep A tests are of two types:
-
Rapid antigen detection test (RADTs).
-
Throat culture test.
Strep A infections can be identified by two different procedures:
Rapid Antigens Detection Test (RADTs) :
-
A rapid antigen detection test is used to identify the antigens (a foreign toxic substance that induces an immune response in the body) to the strep A bacteria.
-
It is performed using a swab that is swept around the throat, and a test is done on a swab.
-
This test tells rapidly if the strep A bacteria is causing an infection. It provides test results within 10 to 15 minutes.
Throat Culture Test:
-
The throat culture test takes more time to detect strep A bacterial growth on the swab; however, it provides a more accurate diagnosis than the rapid antigen detection test.
-
A throat culture test detects strep A infections if in case it is missed by a rapid antigen test.
-
In a throat culture test, patients are asked to keep their mouths open wide, and a sample is swept from the back of the throat and placed in a special plate (culture plate that induces bacterial growth in the lab), which is then sent to the lab for identification of specific infection using chemical tests.
-
Growth of bacteria on the special plate (culture plate) indicates a positive test (persons with strep A infection), and absence of growth indicates a negative test (person with no strep A infections).
-
Throat culture provides test results in 24 to 48 hours.
When Is Strep A Test Indicated?
-
In case of severe throat ache.
-
High fever.
-
Difficulty in swallowing.
What Is the Treatment of Group A Streptococcal Infections?
-
Clinical Examination and History: Complete history of the person for presenting signs and symptoms is recorded. A clinical examination is done to rule out swollen tonsils and lymph nodes of the neck. The presence of cough and runny nose indicates viral infections (not seen in bacterial infection).
-
Antibiotics: Antibiotics like Amoxicillin and Penicillins are prescribed by the doctor, which helps reduce the infection and also prevent its spread to other people.
Prevention:
-
Practice good hygiene by washing hands frequently (especially after sneezing and coughing or after coming in contact with infected people).
-
Cover the mouth and nose with a handkerchief while sneezing or coughing to avoid the spread of the droplets.
-
Use alcohol-based hand rub (hand sanitizers) if soap and water are not available.
-
Avoid staying in a closed room or chamber with infected people for a longer duration.
-
Wash the glass, utensils, and plates separately if sick.
Complications:
Serious complications that can arise if the infection spreads throughout the body are:
-
Post streptococcal kidney disease.
-
Ear infections.
-
Streptococcal toxic shock syndrome (serious infections causing low blood pressure and failure of body organs resulting in death).
-
An abscess (formation of pus pockets in the neck).
Conclusion:
Group A streptococci are very common bacteria responsible for a wide range of infections in body. Swelling of the throat and tonsils (strep throat) is one of the most common infections that affect both children (mostly) and adults. Strep A test is done to rule out the presence of group A streptococcus bacteria by rapid antigen detection test or a throat culture test. Early diagnosis of the group A streptococcal infection using the Strep A test is crucial for immediate management of the infection and to prevent the spread of the infection to other parts of the body. Any delay in the diagnosis can result in potential complications affecting the heart or kidney, resulting in multi-organ failure and death.
