What practitioners need to know about invasive strep A infections

Canadian news agencies are highlighting the record number of invasive Group A streptococcal (iGAS) infections in Canada.1,2 To assist healthcare providers in advising patients, here are the key points about iGAS infections.In January 2000, iGAS became a notifiable disease nationally. Since the early 2000s, the incidence of iGAS has gone up steadily.3 In 2023, the Public Health Agency of Canada received more than 4,600 invasive group A streptococcus samples—the highest annual total recorded in Canada and more than 40% higher than the previous peak of 3,236 in 2019.2 Group A streptococcus (GAS) bacteria, Streptococcus pyogenes, are Gram-positive beta-hemolytic bacteria, with more than 240 genotypes identified.3 These bacteria can be present on the skin and throat of asymptomatic carriers. However, they can also cause a range of clinical presentations, from mild non-invasive infections to invasive disease.3 GAS bacteria can be spread by direct contact with infected wounds on the skin, fluids from the nose or throat of infected persons (e.g., when an infected person coughs or sneezes, or shares drinking cups, eating utensils or cigarettes).3,4 Most GAS infections are mild illnesses such as “strep throat,” impetigo or pyoderma.4,5In mid-December 2023, the number of iGAS infections in Ontario was reported to be higher than in the fall of 2022.6 Similar increases have been reported in other provinces and territories.6 For example, British Columbia reported 51 cases of iGAS in 2023 in people under the age of 20, while only 20 cases were reported in this age group in 2022.7On Jan. 11, 2024, Public Health Ontario reported 540 confirmed iGAS cases in Ontario from October to December 2023, corresponding to an overall incidence rate of 3.5 cases per 100,000 population. The highest rate was in those 65 years of age or older (6.2 cases per 100,000 population), followed by those between the ages of five through nine years (4.9 cases per 100,000). During that period, 48 people died from strep A infections in Ontario, including 23 people aged 65 years or older, 19 in the 18–64 years age group and six children under the age of nine.8Early recognition and prompt aggressive management are critical, as iGAS infections can progress very quickly and lead to serious and life threatening infections, including sepsis, necrotizing fasciitis (flesh eating disease), toxic shock syndrome, pneumonia, meningitis and puerperal sepsis (infection in the postpartum period).3,6Groups at higher risk of iGAS3,6,9Infants and young childrenPeople who are pregnant or postpartumAdults ≥ 65 years of ageImmunocompromised individualsPeople with wounds, conditions causing breaks in the skin (e.g., chickenpox), recent surgeryIndividuals with chronic diseases (e.g., diabetes, lung disease, liver disease, heart disease)Homeless people, those using drugs by injectionPeople with a recent viral infection (e.g., influenza, chickenpox, COVID-19, respiratory syncytial virus).6,9 Vaccination to prevent the occurrence of viral infections might reduce the risk for iGAS.9 Recent close contact with someone with a GAS or iGAS infection.SymptomsSymptoms of non-invasive infection with GAS include:FeverPharyngitis (sore painful throat)Skin infection such as impetigoScarlet fever (less common presentation)Symptoms preceding the onset of iGAS disease vary. They may be vague and include pain of unusual severity, swelling, fever, chills, flu-like symptoms, generalized muscle aches, generalized macular rash, bullae, nausea, vomiting, diarrhea, malaise or joint pain.5Signs and symptoms of specific iGAS infections can include the following:Septicemia (blood poisoning) – symptoms include fever, chills, headache, generally not feeling well, pale skin, lack of energy, rapid breathing, increased heart rate and possible multiorgan involvement. Necrotizing fasciitis – early symptoms of include severe pain and swelling, often rapidly getting worse; fever; redness around a wound.Streptococcal toxic shock syndrome – early symptoms include fever; sudden severe pain, often in an arm or leg; dizziness/hypotension; confusion; feelings of having “the flu"; and a flat red rash over large areas of the body.4,5Severity of iGAS infections10–15 people out of 100 will die from an iGAS infection25 people out of 100 with necrotizing fasciitis will dieMore than 35 people out of 100 with streptococcal toxic shock syndrome will die.4Diagnosis Diagnosis requires culture of normally sterile sites (e.g., blood, cerebrospinal fluid) or tissue from deep inside a wound.4 TreatmentManagement of severe iGAS disease involves supportive treatment in hospital using fluids and electrolytes, specific therapy with antimicrobials, and measures to minimize or neutralize the effects of toxin production, when indicated.10 Early and aggressive surgery is often needed for persons with necrotizing fasciitis, to remove damaged tissue and stop the spread of the disease.4An infectious diseases physician should be consulted for management of suspected iGAS.10 Close contacts of severe cases are also offered antibiotics to prevent infection.4 Laboratory testing of antimicrobial sensitivity of the GAS strain is useful in determining appropriate antibiotic therapy. High-dose parenteral therapy is generally required for severe infections. Treatment may continue for two to six weeks.5Further details on empiric antimicrobial therapy, treatment of confirmed cases and management of close contacts are available in references #5,10 and 11. When to seek treatmentThe public should be reassured that serious GAS infections are still rare. However, families should be counselled to be aware of symptoms of concern, and when they should seek clinical care for their infant or child. Since iGAS infections can sometimes develop after a viral respiratory illness, parents of children who have been recently ill can be advised to monitor for one or more signs of severe infections such as:A fever for more than five days in a child of any age Fever with either a fine red rash (sandpaper-like texture), full body rash similar to sun burn in appearance, and/or red swollen tongueA fever in a child under three months of age, a child with immune system issues or complex chronic health conditionsChild is having difficulty breathing (e.g., chest appears to sink in just above or below the breastbone with each breath, you may hear grunting or notice the head bobbing with each breath in a young infant) Pale skin, whitish or blue lipsVery sleepy or having difficulty waking upChild becomes very sick, very quickly.If a child is experiencing any of these symptoms, advise parents/caregivers to seek medical care immediately (e.g., emergency department, urgent or primary care centre).7PreventionThere is no vaccine to prevent group A streptococcal infections.4Advise the public to:Wash hands well, especially after coughing and sneezing and before preparing foods or eating.Keep all cuts and wounds clean. Watch for possible signs of infection (e.g., redness, swelling, drainage, pain) at the wound site. If there are signs of an infected wound, especially with fever, see a doctor as soon as possible. Stay up to date on immunizations, including the updated COVID-19 and flu vaccinesStay at home when sick to prevent the further spread of illness.4,7References1. Crawley M, Pelley L. Aggressive, often deadly form of strep hits record-high case numbers in Canada. CBC News; January 17, 2024. (accessed January 23, 2024).2. Otis D. Record number of invasive strep A infections in Canada, 6 children dead in Ontario. CTV News; Published January 17, 2024, updated January 19, 2024. (accessed January 23, 2024).3. Health Canada. Group A streptococcal diseases: for health professionals. June 28, 2023. (accessed January 23, 2024).4. BC Centre for Disease Control. Streptococcal disease, invasive, Group A. Information for health professionals. (accessed January 23, 2024).5. Alberta Public Health. Disease management guidelines. Streptococcal disease Group A. April 2023. (accessed January 23, 2024).6. Ontario Ministry of Health. Memorandum: Increased invasive Group A streptococcal disease (iGAS) in Ontario. December 15, 2023. (accessed January 23, 2024).7. BC Centre for Disease Control. B.C. experiencing higher levels of invasive group A streptococcal infections in children. December 22, 2023. (accessed January 23, 2024).8. Public Health Ontario. Invasive Group A streptococcal (iGAS) disease in Ontario: October 1, 2023 to December 31, 2023. Published: January 11, 2024. (accessed January 23, 2024).9. US Centers for Disease Control and Prevention. Notes from the field: increase in pediatric invasive Group A streptococcus infections — Colorado and Minnesota, October–December 2022. MMWR 2023;72(10);265-7. (accessed January 23, 2024).10. Moore DL, Allen UD, Mailman T; Canadian Paediatric Society Infectious Diseases and Immunization Committee. Invasive group A streptococcal disease: management and chemoprophylaxis. Paediatr Child Health 2019 24(2):128. (accessed January 23, 2024).11. US Centers for Disease Control and Prevention. Group A streptococcal (GAS) disease: for clinicians. (accessed January 23, 2024).

What practitioners need to know about invasive strep A infections

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