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Hospital Acquired Group A Streptococcal Infections What have we learned?

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Non-surgical, non-obstetrical infections. most common syndromes. primary bacteremia 33 ... non-surgical/obstetrical (largest group) Summary ... – PowerPoint PPT presentation

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Title: Hospital Acquired Group A Streptococcal Infections What have we learned?


1
Hospital AcquiredGroup A Streptococcal
InfectionsWhat have we learned?
  • Nov. 20, 2008
  • Nick Daneman
  • Division of Infectious Diseases
  • Sunnybrook Health Sciences Centre

2
Invasive Group A StreptococcusDramatic Illness
3
Invasive Group A StreptococcusDramatic Illness
4
Invasive Group A StreptococcusDramatic Illness
5
Invasive Group A StreptococcusDramatic Illness
6
Invasive Group A StreptococcusDramatic Illness
7
Invasive Group A StreptococcusDramatic Outbreaks
75 CASES, 10 DEATHS
8
Invasive Group A StreptococcusDramatic Hospital
Outbreaks
3 year outbreak of Group A Streptococcal surgical
site infections Mastro NEJM 1990
56 Cases of Group A Streptococcal infection in a
nursery Nelson J. Ped. 1976
9
  • 1 nosocomial case
  • enhanced surveillance
  • isolate storage
  • 2 nosocomial cases within 6months
  • typing of isolates
  • if same strain
  • epidemiologic investigation
  • culture health care workers

CID 2002
10
  • expert opinion
  • review of a handful of literature outbreaks

CID 2002
11
Objectives
  • describe hospital acquired cases of invasive
    group A streptococcal infections in Ontario
  • describe hospital outbreaks of invasive group A
    streptococcal infections
  • in Ontario prospective surveillance
  • systematic review of the literature
  • provide evidence-based recommendations

12
Methods Prospective Surveillance
  • Ontario Group A Strep Study Group
  • population-based surveillance
  • Ontario (population 11,000,000)
  • 1992 - 2000
  • all invasive isolates
  • microbiology labs
  • all Ontario hospitals
  • largest outpatient microbiology lab

13
Methods Definitions
  • invasive
  • group A streptococcus from a sterile site
  • hospital acquired
  • neither present nor incubating at admission
  • outbreak
  • gt 2 cases of culture confirmed, symptomatic GAS
    infection
  • epidemiologically linked
  • caused by same M, T type
  • indistinguishable by PFGE

14
Methods Literature Review
  • MEDLINE database, 1966-2004
  • search terms
  • Streptococcus pyogenes OR group A
    streptococcus OR group A streptococcal
  • nosocomial OR outbreak OR cross-transmission
  • review of reference lists
  • manuscripts reviewed by 2 investigators

15
Objectives
  • describe hospital acquired cases of invasive
    group A streptococcal infections in Ontario
  • describe hospital outbreaks of invasive group A
    streptococcal infections
  • in Ontario prospective surveillance
  • systematic review of the literature
  • evidence based recommendations

16
CID 2005
17
Ontario Prospective Surveillance 1992- 2000
18
Hospital-acquired cases
19
Differences cannot be explained by M-types
20
Group A StrepSurgical Site Infections
  • 96 cases
  • out of 9,078,030 surgical admissions
  • 1.1 cases / 100,000 surgical admissions
  • entire range of surgical procedures
  • digestive tract 28
  • musculoskeletal 24
  • cardiovascular 9
  • nervous system 11
  • skin and soft tissue 9
  • urogyne 8

21
Timing of Invasive Group A Streptococcal Surgical
Site Infections
median 5d
22
Group A StrepPostpartum infections
  • 86 cases
  • out of 1,269,722 live births
  • 0.7 cases / 10,000 live births
  • 1/10 as common as neonatal group B strep
    infections
  • but these were infections of mothers (only 2
    newborn cases, both non-invasive)

23
Post-partum M28 association
24
Post-partum M28 association
  • M28 predominated in CDC postpartum surveillance1
  • also predominates in perineal infection in
    children2
  • express surface protein (R28) related to
    cell-surface molecules in Group B Strep which
    enhance binding to cervical epithelium

1. Chuang CID 2002 2. Mogielnicki Ped 2000 3.
Stalhammar MM 1990
25
Group A StrepNon-surgical, non-obstetrical
infections
  • 109 cases
  • 40 of all cases
  • (despite no mention in nosocomial group A strep
    guidelines)
  • time of onset
  • median 10.5 days
  • range 2d to gt1 year
  • ?community or nosocomial acquisition?

26
Group A StrepNon-surgical, non-obstetrical
infections
  • most common syndromes
  • primary bacteremia 33
  • non-necrotizing soft tissue infection 32
  • lower respiratory tract infection 21
  • necrotizing fasciitis 6
  • 32 / 35 skin infections were associated with
    pre-existing skin breakdown
  • IV lines (16), G-tubes /tracheostomy (6), chronic
    ulcers (5), trauma (2), burns (1), other lesions
    (2)

27
Risk factors for mortality among
hospital-acquired cases
28
Objectives
  • describe hospital acquired cases of invasive
    group A streptococcal infections in Ontario
  • describe hospital outbreaks of invasive group A
    streptococcal infections
  • in Ontario prospective surveillance
  • systematic review of the literature
  • recommendations

29
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30
Complementary methods
31
Number of Outbreaks
Literature
Surveillance
32
Outbreak Magnitude
Literature Review Prospective Surveillance p
Median cases (range) 10 (2-56) 2 (2-10) lt0.001
Median duration (range) 30d (1-1095) 6d (1-30) lt0.001
33
Outbreak Patient Composition
34
Outbreak InitiationIndex Cases
  • 3/4 of indexes cases nosocomial cases
  • two other sources of outbreaks
  • ill health care workers
  • 5 literature outbreaks
  • community-acquired cases
  • 9 of 11 admitted to ICU
  • 5 of 9 necrotizing fasciitis

DiPersio 1996, Holloway 1967, Kakis 2002,
Lannigan 1985, Nicolle 1986, Schwartz
1992 Burnett 1990, Decker 1985, Ejlertsen 2001,
Quinn 1965, Walter 1974
35
Outbreak InitiationRapid Tempo
  • median interval between first two cases
  • literature outbreaks 2.0d
  • surveillance outbreaks 4.5d
  • interval between first two cases lt1 month in
    80 of 81 outbreaks

36
Outbreak Propagation
  • patient to patient 47
  • colonized health care worker 27
  • environmental 9
  • mixed 6
  • insufficient information 11

37
Outbreak PropagationColonized Health Care
Workers
Colonized health care worker
Patient-to-Patient/Environmental
38
Outbreak PropagationColonized Health Care
Workers
  • site of health care worker colonization
  • 31 pharyngeal only
  • 10 anal
  • 2 vaginal
  • 5 skin

39
Outbreak PropagationEnvironmental sources
  • bidet
  • hand shower
  • vinyl sheet
  • airflow mattress
  • multidose vaccine vials (3)
  • food borne outbreak (1)

Claesson 1985, Decker 1976, Gordon 1994, Reid
1983, Rutihauser 1999, Decker 1985
40
Outbreak TerminationTreatment of Colonized HCWs
  • data from 24 literature outbreaks
  • first regimen usually successful
  • pharyngeal carriage only 9/9 (100)
  • nonpharyngeal carriage 11/15 (73)
  • 4 failures
  • 2 ongoing transmission
  • 2 late relapses (4mos and 15mos)
  • all ultimately successfully eradicated

Berkelman 1982, McIntyre 1968, Schaffner 1969,
Viglionese 1991
41
Outbreak TerminationPatient to Patient
Transmission
  • multifaceted control measures required
  • 1st attempt usually unsuccessful (14/25)
  • most effective control measures
  • ward closure (86 success)
  • mass treatment/prophylaxis (69 success)

42
5 Recommendations
43
1 Target all Nosocomial Cases
Hospitalized
CID 2002
44
2 Isolation of Necrotizing Fasciitis
  • 11 community acquired index cases
  • majority due to necrotizing fasciitis admitted to
    intensive care unit
  • ? isolate necrotizing fasciitis on
  • admission (pending cultures)

45
3 immediate investigations
  • current guidelines for single case
  • enhanced surveillance isolate storage
  • short interval between first cases (2-4d)
  • will not prevent second case
  • majority of outbreaks only 2 cases
  • therefore, preemptive investigations

46
4 One month ceiling
  • current guidelines for 2 cases in 6 months
  • type isolates if same strain
  • epidemiologic investigations
  • culturing health care workers
  • virtually no outbreaks with initial interval
    gt1month
  • limit investigations to cases within 1 month

47
5 Tailor Investigation by Ward
Surgery/Labour Delivery
Miscellaneous Wards
  • health care worker carriers
  • broad epi search for linked staff
  • cultures
  • throat, anal, vaginal, skin
  • test of cure for non-pharyngeal carriers
  • patient and environmental reservoirs
  • multifaceted infection control strategies
  • isolation/cohorting
  • disinfection
  • sterilization
  • ward closure
  • mass treatment

48
Summary
  • 12 of invasive group A streptococcal infections
    are hospital-acquired
  • three groups with different characteristics and
    outcomes
  • surgical (1/100,000 surgeries)
  • postpartum (0.7/10,000 births)
  • non-surgical/obstetrical (largest group)

49
Summary
  • 10 of hospital-acquired cases are associated
    with outbreaks
  • 90 of hospital-acquired cases are sporadic
  • when outbreaks do occur they are smaller and
    shorter than those in the literature

50
Summary
  • these complementary data sources lead to 5
    recommendations
  • 1 include all hospital cases in guidelines
  • 2 isolate necrotizing fasciitis
  • 3 immediate investigations after 1 case
  • 4 one month ceiling for linked cases
  • 5 tailor investigations management to ward

51
Acknowledgements
  • Dr. Allison McGeer
  • Dr. Donald Low
  • Karen Green
  • Ontario Group A Streptococcal Study Group

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