Mass Antibiotic Treatment for Group A Streptococcus Outbreaks
Mass Antibiotic Treatment for Group A Streptococcus Outbreaks
Outbreaks of invasive infections caused by group A β-hemolytic streptococcus (GAS) may occur in long-term care settings and are associated with a high case-fatality rate in debilitated adults. Targeting antibiotic treatment only to residents and staff known to be at specific risk of GAS may be an ineffective outbreak control measure. We describe two institutional outbreaks in which mass antibiotic treatment was used as a control measure. In the first instance, mass treatment was used after targeted antibiotic treatment was not successful. In the second instance, mass treatment was used to control a rapidly evolving outbreak with a high case-fatality rate. Although no further clinical cases were seen after the introduction of mass antibiotic treatment, persistence of the outbreak strain was documented in one institution >1 year after cases had ceased. Strain persistence was associated with the presence of a chronically colonized resident and poor infection control practices.
Group A β-hemolytic streptococcus (GAS) has a longstanding association with pharyngitis, skin and soft tissue infection, and pneumonia. In the past decade, reports of GAS-associated necrotizing fasciitis and streptococcal toxic shock syndrome (TSS) have increased. Increasingly, outbreaks of invasive GAS are recognized in long-term care facilities. In the Canadian province of Ontario, 4% of invasive GAS cases occur in long-term care facilities, and of these cases, one third are outbreak associated. In long-term care settings, a high case-fatality rate has been observed (40% to 60%).
Guidelines for control of GAS outbreaks in nursing homes were developed by the Ontario Ministry of Health in 1995. These guidelines emphasize the identification and elimination of colonization through providing antibiotics to those known to be carriers of the bacterium. Although such an approach should minimize antibiotic exposure, carrying it out in practice could be difficult, as cultures may be falsely negative, and persons could become colonized or transmit colonization to others in the interval between culturing and treatment. Antibiotic treatment of all residents and staff would not be subject to such limitations. We present two outbreaks of invasive GAS infection in long-term care facilities in Hamilton, Ontario, Canada. Each was caused by transmission of a single well-characterized outbreak strain, and in both cases, mass antibiotic treatment was used to control the outbreak.
Presented in part at the 12th Annual Scientific Meeting of the Society for Healthcare Epidemiology of America (SHEA), April 6-9, 2002, Salt Lake City, Utah.
Outbreaks of invasive infections caused by group A β-hemolytic streptococcus (GAS) may occur in long-term care settings and are associated with a high case-fatality rate in debilitated adults. Targeting antibiotic treatment only to residents and staff known to be at specific risk of GAS may be an ineffective outbreak control measure. We describe two institutional outbreaks in which mass antibiotic treatment was used as a control measure. In the first instance, mass treatment was used after targeted antibiotic treatment was not successful. In the second instance, mass treatment was used to control a rapidly evolving outbreak with a high case-fatality rate. Although no further clinical cases were seen after the introduction of mass antibiotic treatment, persistence of the outbreak strain was documented in one institution >1 year after cases had ceased. Strain persistence was associated with the presence of a chronically colonized resident and poor infection control practices.
Group A β-hemolytic streptococcus (GAS) has a longstanding association with pharyngitis, skin and soft tissue infection, and pneumonia. In the past decade, reports of GAS-associated necrotizing fasciitis and streptococcal toxic shock syndrome (TSS) have increased. Increasingly, outbreaks of invasive GAS are recognized in long-term care facilities. In the Canadian province of Ontario, 4% of invasive GAS cases occur in long-term care facilities, and of these cases, one third are outbreak associated. In long-term care settings, a high case-fatality rate has been observed (40% to 60%).
Guidelines for control of GAS outbreaks in nursing homes were developed by the Ontario Ministry of Health in 1995. These guidelines emphasize the identification and elimination of colonization through providing antibiotics to those known to be carriers of the bacterium. Although such an approach should minimize antibiotic exposure, carrying it out in practice could be difficult, as cultures may be falsely negative, and persons could become colonized or transmit colonization to others in the interval between culturing and treatment. Antibiotic treatment of all residents and staff would not be subject to such limitations. We present two outbreaks of invasive GAS infection in long-term care facilities in Hamilton, Ontario, Canada. Each was caused by transmission of a single well-characterized outbreak strain, and in both cases, mass antibiotic treatment was used to control the outbreak.
Presented in part at the 12th Annual Scientific Meeting of the Society for Healthcare Epidemiology of America (SHEA), April 6-9, 2002, Salt Lake City, Utah.
