Clinical Notes : Infection and Sepsis

68. Invasive Group A Streptococcus


A Life threatening infection with group A streptococcus (GAS) in parts of the body where it is not usually found

  • muscle

  • blood

  • lungs

 Characterised by :

  • acute febrile illness

  • associated with

    • Streptococcal Toxic Shock Syndrome (STSS).and/or

    • Necrotising Fasciitis (NF)




In the ROI :

  • Up to 30% of the general population are asymptomatic carriers of GAS

  • GAS is spread by

    • Contact with secretions from the nose and throat of infected persons

      • Direct contact with large droplets is the major mode of transmission (kissing)

    • Airborne spread has also been suggested (sneezing)

    • Contact with infected wounds or skin lesions (skin contact)


  • Incidence of iGAS is rising

    • 85% of iGAS is thought to occur sporadically in the community

    • 10% in hospital patients

    • 4% in residents of long-term care facilities

    • 1% occur after close contact with a GAS case


  • Affects all ages

    • Highest in over 75’s

    • Lowest in 10-14 years old

    • 16% of all IGAS in under 10 year old


Increased risk in :

  • Extremes of age: young children, adults > 65 years

  • Skin trauma

  • Young adults exposed to children

  • Immunocompromised patients (e.g. underlying malignancy, HIV infection and high-dose steroid use)

  • Diabetes mellitus

  • Underlying heart or chronic lung disease

  • Alcohol abuse

  • Intravenous drug users

  • Pregnant women

  • Concomitant varicella infection



  • Incubation period:

    • 1 - 3 days

  • Period of communicability:

    • 7 days before the onset of the invasive GAS infection until 24 hours after appropriate antibiotic treatment is commenced.

  • Treatment of infected persons with an appropriate antibiotic for 24 hours or longer generally eliminates their ability to spread the bacteria.



Streptococcal Toxic Shock Syndrome

  • High fever, chills, rigors, sweats

  • myalgia (of typically very sudden onset)

  • localised pain (at site of infection)

  • hypotension ( 50% are initially normotensive but become hypotensive within 4 hrs)

    • fifth percentile of systolic blood pressure in children, or

    • < 90 mmHg systolic pressure in adolescents and adults

  • and two or more of the following:

    • Renal impairment (creatinine > twice upper limit of normal for age)

    • Coagulopathy (platelets < 100,000 X 106/l or evidence of disseminated intravascular coagulation)

    • Liver dysfunction (ALT, AST or bilirubin > twice upper limit of normal for age)

    • Acute respiratory distress syndrome (pulmonary infiltrates and hypoxaemia without cardiac failure or generalised oedema)

    • Generalised erythematous rash that may desquamate

    • Soft tissue necrosis (necrotising fasciitis (NF), myositis, gangrene





Necrotising Fasciitis

  • pain and tenderness out of proportion to the appearance of the area

  • oedema

  • erythema

  • anaesthesia

  • bullae formation

Early Necrotising Fasciitis

Advanced Necrotising Fasciitis

Advanced Necotising Fasciitis



Urgent referral from OOH setting to A+E for

  • lab. investigation

  • IV Rx

  • admission with initial 24 hr isolation


Infection control

Patients in close contact with someone with group A strep should be

  • issued with a GAS information leaflet and

  • informed to look out for any of the symptoms and to seek urgent medical help if they develop any of them

    • High fever

    • Severe muscle aches and/or localised muscle tenderness

    • Redness at site of a wound


A heightened index of suspicion for iGAS in close contacts should be maintained for 30 days after the diagnosis is made in the index patient


If  Invasis GAS infection is diagnosed, chemoprophylaxis should be given to all contacts in the household if they have symptoms suggestive of localised GAS infection (i.e. sore throat, fever, and skin infection)

  • Oral penicillin V (250-500mgs QDS, appropriately adjusted for children for 10 days

  • Azithromycin 12mg/kg/day in a single dose (maximum daily dose of 500mg/day) for five days,

  • In the unlikely event of an allergy to penicillin and azithromycin the local consultant microbiologist or infectious diseases physician should be contacted to

  • discuss a suitable alternative


In nursing homes

  • Following a single nursing home case, the nursing home should review infection control measures and maintain a heightened index of suspicion for 30 days after the diagnosis is made in the index patient.

  • Close contacts among residents (sharing same room or side ward) and staff should only receive chemoprophylaxis if they have symptoms suggestive of localised GAS infection (i.e. sore throat, fever, skin infection) and the more likely diagnosis of a viral upper respiratory tract infection has been excluded.

  • If close contacts have symptoms suggestive of invasive disease (e.g. high fever, severe muscle aches,localised muscle tenderness), they should be immediately referred to the Emergency Department


In Health Care Workers

Antimicrobial prophylaxis is not indicated for most HCWs who have been in contact with an infected patient, where standard infection control precautions have been followed.


Health Protection Agency Interim UK guidelines for management of close community contacts of invasive group A streptococcal disease.

Health Protection Agency,Group A Streptococcus Working Group. Commun Dis Public Health. 2004;7:354-61


Severe invasive group A streptococcal infections: a subject review.       

American Academy of Pediatrics

Pediatrics. 1998; 101: 136–140


Streptococcal toxic-shock syndrome: spectrum of disease, pathogenesis, and new concepts in treatment.

Stevens, DL.

Emerg Infect Dis. 1995; 1: 69–78


Epidemiological and clinical aspects of invasive group A streptococcal infections and the streptococcal toxic shock syndrome.


Eriksson, BKG, Andersson, J, Holm, SE, and Norgren, M

Clin Infect Dis. 1998; 27: 1428–1436


Clusters of invasive group A streptococcal infections in family hospital and nursing home settings.

Schwartz, B, Elliot, JA, Butler, JC et al.

Clin Infect Dis. 1992; 15: 277–284


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