Friday, June 2, 2023
| Term | Definition |
|---|---|
| Invasive group A Streptococcus (iGAS) infection | Isolation of GAS from a normally sterile site, either by PCR or culture. For this study, iGAS also includes GAS infections in which GAS was isolated from a normally nonsterile site in combination with a severe clinical presentation, such as streptococcal toxic shock syndrome or necrotizing fasciitis |
| Group A Streptococcus (GAS) infection | Isolation of GAS from a non-sterile site in combination with clinical symptoms attributable to bacterial infection including fever (temperature ≥38°C), sore throat, wound infection, or cellulitis |
| Group A Streptococcus carriage | Isolation of GAS from a nonsterile site but no symptoms attributable to infection with this microorganism |
| Home healthcare (HHC) | Community health services, including district nursing teams, general practitioners, podiatry (chiropody), community midwifery, hospital outreach, and palliative care, which provide medical or nursing care within a patient’s home |
| Residential care | Live-in accommodation that provides 24-hour care and support to its residents |
Table 1. Definitions used in a study of invasive group A Streptococcus infection associated with home healthcare, England, 2018–2019
| Outbreak no. | No. iGAS cases | No. GAS cases† | No. deaths | No. days from first to last case | No. cases without identified HHC input | emm type | WGS |
|---|---|---|---|---|---|---|---|
| 1 | 14 | 2 | 2 | 136 | 1 | 87 | N |
| 2 | 7 | 1 | 2 | 148 | 0 | 94 | N |
| 3 | 6 | 0 | 3 | 222 | 0 | 94 | Y |
| 4 | 7 | 0 | 2 | 388 | 0 | 89 | Y |
| 5 | 5 | 5 | 2 | 179 | 2 | 89 | N |
| 6 | 3 | 0 | 0 | 75 | 0 | 1 | Y |
| 7 | 4 | 0 | 0 | 219 | 0 | 1 | Y |
| 8 | 2 | 0 | 1 | 3 | 0 | 89 | Y |
| 9 | 9 | 1 | 1 | 507 | 0 | 89 | Y |
| 10 | 39 | 95 | 15 | 487 | 1 | 44 | Y |
| Total | 96 | 104 | 28 | NA | 4 | NA | NA |
Table 2. Summary of home healthcare–associated invasive group A Streptococcus infection outbreaks, England, 2018–2019*
*GAS, group A Streptococcus; HHC, home healthcare; iGAS, invasive group A Streptococcus; NA, not applicable; WGS, whole-genome sequencing. †Noninvasive GAS was not systematically investigated or recorded in all outbreaks. Available data did not enable distinction between carriage and noninvasive infection.
| Characteristics | No. (%) | IQR (range) |
|---|---|---|
| All outbreaks, n = 10 | ||
| Total cases | 96 (100) | NA |
| Total deaths | 28 (29) | NA |
| Median cases | 7 | 4–9 (2–39) |
| Median outbreak duration, d | 199 | 139–347 (3–507) |
| Outbreaks with case data, n = 9 | ||
| Case-patient characteristics, n = 57 | ||
| Median age, y | 83 | 77–90 (42–100) |
| Sex | ||
| F | 39 (68) | NA |
| M | 18 (32) | NA |
| Median days between cases | 21 | 6–46 (1–225) |
| Type of residence, n = 48 | ||
| Residential care | 17 (35) | NA |
| Own home | 31 (65) | NA |
| HHCW exposure, n = 96 | ||
| Patient receiving care | 92 (96) | NA |
| Household contact of recipient | 2 (4) | NA |
| None identified† | 2 (4) | NA |
Table 3. Characteristics of home healthcare–associated invasive group A Streptococcus infection outbreaks, England, 2018–2019*
*HHCW, home healthcare worker; NA, not applicable.
†Cases linked to outbreaks through whole-genome sequencing but without any identified connection to home healthcare services.
This activity is intended for primary care physicians, infectious disease specialists, and other physicians who treat and manage frail patients at risk for invasive group A Streptococcus.
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Healthcare-associated invasive group A Streptococcus (iGAS) outbreaks are common worldwide, but only England has reported outbreaks associated with home healthcare (HHC). We describe 10 outbreaks during 2018–2019 in England. A total of 96 iGAS cases (range 2–39 per outbreak) and 28 deaths (case-fatality rate 29%) occurred. Outbreak duration ranged from 3–517 days; median time between sequential cases was 20.5 days (range 1–225 days). Outbreak identification was difficult, but emm typing and whole-genome sequencing improved detection. Network analyses indicated multiple potential transmission routes. Screening of 366 HHC workers from 9 outbreaks identified group A Streptococcus carriage in just 1 worker. Outbreak control required multiple interventions, including improved infection control, equipment decontamination, and antimicrobial prophylaxis for staff. Transmission routes and effective interventions are not yet clear, and iGAS outbreaks likely are underrecognized. To improve patient safety and reduce deaths, public health agencies should be aware of HHC-associated iGAS.
Streptococcus pyogenes (group A Streptococcus; GAS) is a common community-acquired pathogen, predominantly affecting skin, soft tissues, and the respiratory tract. Invasive GAS (iGAS) infection, characterized by entry of the bacterium into sterile body fluids, including blood, has a mortality rate of 8%–16%[1–4]. Person-to-person iGAS transmission is thought to occur through direct skin contact or via respiratory droplets from symptomatic infections and asymptomatic carriers. Throat, nose, skin, and anogenital carriage have been linked to healthcare-associated outbreaks[5–8], which have been recorded in hospital, long-term care, and outpatient facilities worldwide[9–11]. Environmental and fomite transmission are less well characterized.
In England, most community nursing care is performed by practitioners traveling between patients to deliver healthcare in the patients’ homes, termed home healthcare (HHC). HHC is administered by a variety of healthcare workers, including district nurses, community nurses, healthcare assistants, general practitioners, podiatrists, hospital outreach teams, and palliative care staff. A substantial part of HHC is wound care, but HHC workers (HHCWs) also administer medication, assist with rehabilitation, and perform catheter and end of life care. During a single working week, an HHCW could perform many of these duties for different patients.
The home environment is not designed for healthcare and has unique infection control challenges. HHCWs and their equipment could become contaminated directly from the patient or the patient’s home, and the patient risks infection from practitioners or their equipment[12,13].
In England, iGAS cases are notifiable to local health protection teams (HPTs) under the Health Protection (Notification) Regulations 2010[14] as a means of beginning immediate public health actions as needed, including contact tracing, according to national guidelines[15]. Guidance also requests that all sterile site GAS isolates be sent for typing to the Respiratory and Vaccine Preventable Bacteria Reference Unit (RVPBRU) of Public Health England (PHE). All isolates, including GAS isolates from possible healthcare-associated infections, should be referred for typing or stored locally for future outbreak investigations. RVPBRU returns results to the referring hospital and local HPT within 6 days. RVPBRU also provides whole-genome sequencing (WGS) to support outbreak investigations.
In 2013, PHE identified the first HHC-associated iGAS outbreak in England[16]. PHE has regularly recorded outbreaks since then, and HPTs managed outbreaks with advice from national leads for streptococcal surveillance and reference microbiology units. We describe HHC-associated iGAS outbreaks reported during January 2018–August 2019, including identification, investigation, and management, to inform public health response in England and elsewhere.
