Group A Streptococcus pyogenes Rising incidence of severe

Group A Streptococcus pyogenes

Rising incidence of severe Invasive GAS disease JAMA, 1993; 269: 384 • Streptococcal toxic shock syndrome defined: – GAS infection – Hypotension – Multi-organ failure (2 or more of the following): • • • Hepatic involvement Renal involvement Gastrointestinal involvement ARDS Hematologic involvement – Generalized skin involvement

IGAS in Ontario, Canada NEJM, 1996; 335: 547 • Population-based surveillance, 1992 -3 in Ontario, Canada, N=323 patients: – 1. 5 per 100, 000 – Highest risk: • Very young, very old • 56% had underlying disease: – – – HIV Cancer Diabetes Alcohol abuse Chickenpox

IGAS in Ontario, Canada NEJM, 1996; 335: 547 • Clinical presentations: – – – Soft tissue infection Bacteremia without focus Pneumonia Necrotizing fasciitis STSS • Mortality – Over 64 years – STSS 15% 29% 81% 48% 14% 11% 6% 13%

IGAS Case Definition • Clinical description – Invasive group A streptococcal infections may manifest as any of several clinical syndromes, including pneumonia, bacteremia in association with cutaneous infection (e. g. , cellulitis, erysipelas, or infection of a surgical or nonsurgical wound), deep soft-tissue infection (e. g. , myositis or necrotizing fasciitis), meningitis, peritonitis, osteomyelitis, septic arthritis, postpartum sepsis (i. e. , puerperal fever), neonatal sepsis, and nonfocal bacteremia.

IGAS Case Definition (2) • Laboratory criteria for diagnosis – Isolation of group A Streptococcus (Streptococcus pyogenes) by culture from a normally sterile site (e. g. , blood or cerebrospinal fluid, or, less commonly, joint, pleural, or pericardial fluid) • Case classification – Confirmed: a case that is laboratory confirmed • Comment – See also Streptococcal toxic shock syndrome

STSS Case Definition • Streptococcal toxic-shock syndrome (STSS) is a severe illness associated with invasive or noninvasive group A streptococcal (Streptococcus pyogenes) infection. STSS may occur with infection at any site but most often occurs in association with infection of a cutaneous lesion. Signs of toxicity and a rapidly progressive clinical course are characteristic, and the case-fatality rate may exceed 50%.

STSS Case Definition (2) • Clinical case definition – An illness with the following clinical manifestations occurring within the first 48 hours of hospitalization or, for a nosocomial case, within the first 48 hours of illness: • Hypotension defined by a systolic blood pressure less than or equal to 90 mm Hg for adults or less than the fifth percentile by age for children aged less than 16 years. • Multi-organ involvement characterized by two or more of the following (next slide):

STSS Case Definition (3) Multi-organ involvement characterized by two or more of the following: 1. Renal impairment: 2. Coagulopathy: 3. Liver involvement: 4. Acute respiratory distress syndrome: 5. A generalized erythematous macular rash that may desquamate. 6. Soft-tissue necrosis, including necrotizing fasciitis or myositis, or gangrene. • Laboratory criteria for diagnosis • Isolation of group A Streptococcus.

STSS Case Definition (4) • Case classification – Probable: a case that meets the clinical case definition in the absence of another identified etiology for the illness and with isolation of group A Streptococcus from a nonsterile site. – Confirmed: a case that meets the clinical case definition and with isolation of group A Streptococcus from a normally sterile site (e. g. , blood or cerebrospinal fluid or, less commonly, joint, pleural, or pericardial fluid). • Comment – See also Streptococcal Disease, Invasive, Group A and Toxic Shock Syndrome

Public Health Action • Case ascertainment • Use the supplemental form to: – Document underlying disease – Document type of infection – If the case was hypotensive: • Determine if the case of invasive Group A Streptococcus meets the case definition for streptococcal toxic shock syndrome

Prophylaxis CID, 2002; 35: 950 • 2 studies identified 5 cases of household transmission in 2874 cases of IGAS, all adults. – Do not routinely screen or prophylax. – Health officials ‘may choose to’ offer prophylaxis to household contacts most at risk for sporadic disease or death • Health-case associated case: – Investigate one case (enhanced surveillance, typing) – Screening epi-linked health care workers is strongly recommended if > 2 cases occur in a 6 month period

IGAS - Outbreak Example JAMA, 1997; 277: 38 • February, 1995: 4 patients with IGAS; 2 deaths from STSS in a 10 -day period. • Action: – PFGE – Case definition: IGAS matching the outbreak strain with onset Jan 1 to Mar 31, 1995 in a 17 county area (subsequently revised to a 3 -county area) – Active surveillance – Survey of school children and patients with pharyngitis

IGAS - Outbreak Example (2) JAMA, 1997; 277: 38 • Results: – Case-finding: • 7 cases that matched by PFGE; ‘outbreak clone’ – 4 adults lived in community A served by school A – 4 deaths – Pharyngitis due to the outbreak clone • Community A: 7 (58%) of 12 persons with GAS • Community B: 69 (26%) of 260 persons with GAS

IGAS - Outbreak Example (3) School Survey JAMA, 1997; 277: 38 School Total students screened No (%) GAS isolates = outbreak clone A 187 No (%) with GAS 59 (32) X 337 53 (16) 0 (0) Y 260 30 (12) 3 (10) Z 299 68 (23) 1 (1) 46 (78)

IGAS/STSS Summary • STSS is more severe form of Streptococcus pyogenes infection – Highest risk in elderly and individuals with chronic underlying disease • Investigation: – Case ascertainment for IGAS and STSS – Document • Diagnosis • Underlying disease