Group A Streptococcal Infections ( GAS ) Guideline

Publication: 21/02/2008  
Next review: 02/01/2023  
Clinical Guideline
ID: 1271 
Approved By: Trust Clinical Guidelines Group 
Copyright© Leeds Teaching Hospitals NHS Trust 2020  


This Clinical Guideline is intended for use by healthcare professionals within Leeds unless otherwise stated.
For healthcare professionals in other trusts, please ensure that you consult relevant local and national guidance.

Group A Streptococcal Infections (GAS): Guideline for prevention and control of Group A streptococcal infections in acute healthcare and maternity

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Summary of Guideline

Actions required to assess and manage cases of Group A streptococcal infection in the healthcare setting.

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Group A Streptococcus, or Streptococcus pyogenes, is a bacterium which can cause a wide spectrum of disease, from asymptomatic carriage to severe invasive infection, e.g. necrotising fasciitis. It is the most common cause of “Strep throat” and can also be associated with cellulitis and puerperal sepsis. Invasive Group A Streptococcal infection, or iGAS, is a rare but serious illness. It is associated with the isolation of GAS from a normally sterile site such as blood, cerebrospinal fluid, joint aspiration, pericardial/peritoneal/pleural fluids, bone, deep tissue or at operation or post-partum. Other presentations of GAS infection include Toxic Shock Syndrome (TSS) and necrotising fasciitis.
Group A Streptococci can spread readily from person to person, via direct contact or droplet spread.

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Group A Streptococcal infection should be considered in all patients with skin and soft tissue infection (especially necrotising fasciitis), throat infection, scarlet fever and puerperal sepsis. This list is not exhaustive.
 Take appropriate samples in the context of each clinical presentation e.g. blood cultures, wound swabs, high vaginal swab  (HVS) , throat swabs, etc.

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Treatment / Management

Treatment guidance can be found using the Antimicrobial Guidelines page of the Trust Intranet. Alternatively, advice can be obtained by contacting Microbiology on extension 23962.

All cases of suspected GAS infection identified in the acute care setting or maternity units and any cases identified within seven days of discharge or delivery that could be healthcare associated should be reported to the Infection Prevention and Control Team (IPCT).
iGAS is a notifiable disease in England, Wales and Scotland. All iGAS cases should be notified to the local Health Protection Unit (HPU) by the relevant clinician and microbiologist.

Source Isolation:

  • Patients diagnosed with or clinically suspected of having GAS infection should be source isolated in a single room, ideally with en-suite facilities. In puerperal cases, mother and baby should be kept together unless either one of them requires admission to ICU. See LTHT Isolation Guideline.
  • Patients with GAS should remain in source isolation until they have had a minimum of 24 hours of effective antibiotic therapy. See LTHT Antimicrobial Guidelines
  • Some patients should remain source isolated for longer:
    • Cases of necrotising fasciitis;
    • Other cases where there is significant discharge of potentially infected body fluids or high risk of shedding;
    • Mothers and neonates on maternity units;

These must ALL be isolated until culture negative. Repeat samples should be collected at 48 hour intervals until negative results are obtained, at which point source isolation can cease.

Personal Protective Equipment (PPE):

  • Whilst the patient is considered infectious, healthcare workers (HCW’s) must wear PPE including disposable gloves and aprons when in contact with the patient and their equipment or immediate surroundings.
  • Where risk of transmission from droplets is identified, fluid repellent surgical masks and eye shields/ visors are recommended. These must be worn for dressing changes and any operative debridement of cases of necrotising fasciitis.
  • Where there is risk of transmission from a HCW e.g. suturing perineum in maternity then surgical face masks are recommended.
  • Breaks in the HCW’s skin must be covered by a waterproof dressing.

Hand Hygiene

  • HCW’S must adhere strictly to the LTHT Hand Hygiene Policy, using alcohol gel or soap and water before and after every contact with the patient and their immediate environment. Patients and visitors should also be advised to do the same.

Environmental Cleaning

  • The isolation room, furniture and equipment must be cleaned as per cleaning guidelines for source isolation. A chlorine releasing agent with a minimum of 1,000 PPM available chlorine should be used on a daily basis (LTHT Isolation Guideline)
  • Communal facilities such as baths and showers should be cleaned and decontaminated between all patients especially on delivery suites, post-natal wards and other high risk areas.

Linen and Waste

  • Whilst the patient is considered infectious, linen and waste must be handled as hazardous. Red alginate bags are required. LTHT Isolation Guideline.

Transferring Patients

  • In order to minimise the risk of cross-infection, the transfer of any patient with an infection to another healthcare facility/ ward is not recommended unless unavoidable or essential to the individual’s clinical care. If transfer is taking place, details of the risk of infection must be effectively communicated to the porters/ ambulance service, receiving ward/ department or facility, and the receiving IPCT must be informed using the inter-healthcare transfer form. If it is found that a case of GAS could have acquired the infection in another hospital, that information should be relayed to the relevant hospital. Refer to the LTHT Transfer and Handover of Care Procedure for advice.

Communication with Mortuary and Pathology Staff

  • In the event of a patient death, the mortuary staff should be informed of the nature and risk of the infection and a cadaver bag should be used as per LTHT Standard Infection Prevention and Control Precautions Guideline.
  • If unfixed tissue from a case of necrotising fasciitis is sent for histopathological examination, the request form should clearly state that it is from a suspected case of necrotising fasciitis.

Infections Occurring in Mothers and Babies

  • Although peri-partum GAS infection is typically acquired at the time of or after childbirth, pregnant women who are found to be infected with or carrying GAS earlier in pregnancy should be treated at the time and have this clearly documented in the maternity notes.
  • Babies born to infected or colonised mothers may also become colonised. Occasionally the baby may develop infection, including invasive disease. Maternal and neonatal infections tend to be closely related in terms of timing. Mother and baby should not be separated unless one or other requires admission to ICU. If nursed together, they should both be source isolated. If either develops suspected or confirmed iGAS in the neonatal period (first 28 days of life) then both mother and baby should receive antibiotic treatment.

Transmission from Patient to Close Personal Contacts

  • Antibiotics do not need to be routinely given to contacts of GAS cases. In iGAS, the Health Protection Agency (HPA) Interim Guidelines for Management of Close Community Contacts of iGAS (2004) should be followed.
  • It is important that suitable and accurate information is communicated to any patient with iGAS infection and their close personal contacts by the responsible consultant or a member of their team.
  • Close contacts of iGAS cases should receive written information and have a heightened awareness of the signs and symptoms of GAS for 30 days after the diagnosis in the index case. This is the responsibility of the local Health Protection Unit (HPU).
  • All HCW’s should be fully informed at handover of shifts so that communication with the patient and their family is consistent, accurate and documented.

 Transmission from Patient to Healthcare Worker

  • HCW’s working without appropriate PPE whilst a patient is infectious and coming into direct contact with droplets, wounds or body fluids, should be advised about the signs and symptoms of GAS infection and have a heightened awareness of the signs and symptoms of GAS infection for 30 days after the exposure and if symptomatic, seek urgent medical advice. Any such exposed HCW should be referred to Occupational Health.
    • Antibiotic prophylaxis should be considered for HCW’s who sustain a needlestick injury or direct contamination of mucous membranes or breaks in the skin with material potentially infected with GAS. (LTHT Prevention and Management of an Inoculation Incident (Body Fluid Exposure Incident Including Needlestick Injury Policy)  The decision to treat should be made on a case-by-case basis after discussion between a microbiologist or other infection specialist and an occupational health practitioner, taking into account the type of exposure and the length of time the index patient has been on antibiotics. If prophylaxis is recommended, HCW’s should receive a 3 day course of Amoxicillin 500mg orally  three times daily. Alternatives should be given in the case of allergy.  A full treatment course should be given if there is evidence of active infection in the HCW.

    Transmisison from Patient to Patient

    • This is minimised by practicing strict source isolation (Isolation Guideline) and fullcompliance with LTHT Standard Infection Prevention and Control Precautions Guideline . If necessary, the IPCT will review if other recent cases are connected.
    • Antibiotics should not be routinely administered except in exceptional circumstances .

    Transmission From HCW to Patient

    • Although many healthcare-associated GAS infections will arise from the patient’s own endogenous flora, some patients will acquire their infection from a HCW. The IPCT will investigate if cases are healthcare acquired and in some situations this may involve screening of HCWs.
    • For a single case of healthcare-associated GAS, all HCW’s in contact or working in close proximity to the patient (bed space, theatre, delivery room) will be considered as possible sources of healthcare-associated GAS. The HCW’s most likely to have transmitted GAS are those with direct contact with the patient within seven days of the onset of the infection. In particular, the following groups will be considered for screening:
      • those present in theatre and performing post-operative dressing changes for surgical cases
      • those performing vaginal examinations or dealing with episiotomies and those present at delivery for maternity cases

    The IPCT may take a step-wise approach to any investigation for a health care worker who is the source as required.

     Investigation of Acquisition (Single Case)

     Initial investigations should establish if the infection or colonisation with GAS is community or healthcare-associated. This will be undertaken by the IPCT.
    If the positive sample was taken within 48 hours of admission, the GAS was most likely acquired in the community.
    If the positive sample was taken more than 48 hours after admission, the following need to be considered:  

    • An assessment should be made as to whether the patient had any symptoms or signs in keeping with GAS infection at the time of admission. If they did, the GAS was most likely acquired in the community.
    • If no symptoms or signs in keeping with GAS infection at admission, consider whether the patient could have long-standing carriage of GAS. This would apply mainly to samples from mucosal sites, e.g. throat swabs, sputum, high vaginal swabs. A review of previous samples could aid decision making. If assessed to have long-standing carriage, then the GAS was most likely acquired in the community.
    • If no symptoms or signs in keeping with GAS at admission and patient does not have long-standing carriage of GAS, assess the likely portal of entry of the organism. Is there an associated surgical site, cannulation site, line or other device (making healthcare-associated acquisition more likely) or is there no obvious portal, making infection with the patient’s own flora more likely?

    This assessment will be carried out by the Infection Prevention Nurses in conjunction with a Consultant Microbiologist. If a case is determined to be healthcare-acquired after this assessment, an investigation as to the source will take place.

    Screening of HCWs

    A decision may be made to screen staff for GAS following evidence of a healthcare associated infection or as part of an investigation into an outbreak. In most situations screening samples will be taken from the throat and any areas of broken skin. Further sample types may be necessary on a case by case basis.

    • In this situation it is compulsory for staff to be screened, as an unscreened staff member may continue to act as a source of GAS infection in patients.
    • The Outbreak Control Team should ensure that the clinical and non-clinical leads within the clinical area(s) act as positive role models and take on the responsibility of providing their staff with information regarding the screening process (with IPC Team and Occupational Health Service (OHS) support), communicate to staff why the screening is essential, the need for all staff to positively comply with screening and the process for supporting staff who test positive for GAS
    • A list of staff requiring screening must be agreed by the Outbreak Control Team and supplied to OHS in a secure form.
    • The screening process is co-ordinated by OHS, and carried out jointly by the IPC Team and OHS. It may include peer-testing and/or self-testing.
    • Request forms must be filled in with the location specified as OHS, so that results are returned to OHS only and not the clinical area and do not appear on the PPM+..
    • OHS will maintain a secure database of results, which will only be shared with the Chair of the Outbreak Control Team.
    • All Staff found positive will be assessed for the presence of possible GAS-disseminating lesions (e.g. wounds, eczematous lesions etc.). If present these will be investigated and treated accordingly.
    • Any staff member found GAS positive on screening will receive advice from OHS regarding further treatment and any requirement to be absent from work.
    • The staff member will refrain from work that involves contact with patients or their environment for the first 48 hrs of decolonisation. This may require absence from work.
    • Staff will be followed up by OHS and re-screened as outlined in National Guidelines (J.A.Steer et al 2012)

    Staff found to be positive for GAS during investigation of an infected lesion
    Staff may be found to be positive for GAS during investigation of an infected lesion (usually a skin lesion), either by their own doctor or OHS.

    • If the staff member becomes aware of this through medical care other than OHS, he/she should report this to OHS.
    • OHS will contribute to the staff member’s investigation and treatment, liaising with other medical staff as appropriate.
    • Decisions relating to treatment, screening and removal from clinical contact will depend on individual circumstances and will be made in consultation with the IPCD (or deputy).

    OHS should inform the IPCT of the name and work location of any GAS positive staff member so that recent GAS data from his/her clinical area can be checked to see if there might be associated GAS cases that had not been flagged as a possible outbreak. Subsequent IPC actions will depend on the result of the investigation

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Record: 1271
  • To provide Infection Prevention and Control guidance on the management of patients from whom Group A Streptococcus (GAS) has been isolated and, if necessary, any known contacts.
  • To inform the process of deciding whether the GAS is hospital or community associated, and provide guidance how to conduct any subsequent investigations if the GAS is considered to be healthcare associated.
  • To provide evidence-based recommendations for appropriate investigation and management of GAS infection in the acute healthcare and maternity setting.
Clinical condition:

Group A Streptococcal isolation on samples

Target patient group: Patients in the LTHT secondary care setting
Target professional group(s): Secondary Care Doctors
Secondary Care Nurses
Adapted from:

Evidence base

Resources used:

  • Department of Health and health Protection Agency Guidelines
  • Journal publication
  • Expert opinion

Health Protection Agency (2004) Interim UK guidelines for management of close community contacts of invasive

J.A.Steer et al (2012) Guidelines for prevention and control of group A streptococcal infection in acute healthcare and maternity settings in the UK. Journal of Infection 64, 1e18

Approved By

Trust Clinical Guidelines Group

Document history

LHP version 2.0

Related information

Not supplied

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