Two outbreaks of primarily noninvasive group A streptococcal disease in the same nursing home, New York, 1991

Risk factors associated with group A Streptococcus acquisition in a large, urban homeless shelter outbreak

OBJECTIVE

Group A Streptococcus (GAS) is a frequent cause of outbreaks in healthcare institutions, yet outbreak reports in the literature from homeless shelters are less common, despite an increased risk of severe GAS infection in homeless populations. In 2016, we conducted a case-control study to identify significant risk factors associated with GAS acquisition in a protracted, 19-month outbreak of GAS in a large, urban men's homeless shelter in Ontario, Canada.

METHODS

Cases (individuals with either clinical GAS emm74 infection or asymptomatic carriers of GAS emm74) and controls were identified from shelter residents from February to September 2016. Information on demographics, clinical presentation, pre-existing health conditions, and risk factors for GAS transmission were collected for all study participants from a variety of sources, including the public health notifiable disease information system, electronic health records, the shelter electronic information system, and interviews with client services workers.

RESULTS

From the multivariable logistic regression model, younger individuals (OR 9.1; 95% CI 1.57-52.9), those with previous skin conditions (OR 56.2; 95% CI 2.73-1160), and those with recent wounds (with wound care: OR 51.5, 95% CI 8.86-299, and without wound care: OR 77.4, 95% CI 7.38-812) were found to be at increased risk of acquiring GAS in this outbreak.

CONCLUSION

The outbreak investigation clearly demonstrated the need for improved wound care and infection prevention and control practices, for early screening and detection of skin and soft tissue infections, and for a comprehensive, integrated electronic information system in homeless shelters.

Invasive group A streptococcal infection outbreaks of typeemm118 in a long-term care facility, and of type emm74 in the homeless population, Montréal, Quebec

Background

Two invasive group A streptococcus (iGAS) infection outbreaks occurred in Montreal in 2016 and 2017; one in a long-term care facility (type emm118) and one in the community, primarily involving homeless people (type emm74).

Objective

To describe two recent iGAS outbreaks in Montréal and highlight the challenges in dealing with these outbreaks and the need to tailor the public health response to control them.

Methodology

All cases of iGAS were investigated and the isolates were sent to the laboratory for emm typing. In both outbreaks, cases of superficial group A streptococcus (GAS) infection were identified, through 1) systematic case detection accompanied by screening for asymptomatic carriers among residents and employees of the long-term care facility and 2) sentinel surveillance among homeless people. Visits were made to community organizations providing homeless services (including shelters) and social networks were analyzed to establish whether there were any links among cases of GAS infection (both invasive and noninvasive) and locations frequented. In both outbreaks, recommendations were made to service providers regarding enhancement of infection prevention and control measures.

Results

In the long-term care facility, five cases of type emm118 iGAS were identified over a 22-month period, one of which resulted in death. All residents were screened and no carriers were identified. Among the employees, 81 (65%) were screened and fourcarriers were identified. Of those, one was a carrier of type emm118 GAS. All carriers were treated, and subsequent follow-up sampling on three carriers (including the one with emm118) was negative.

In the community, 23 cases of type emm74 iGAS were detected over a 16-month period, four of which resulted in death. Half of the cases (n=12) were described as homeless, and six others were users of services for the homeless. Sentinel surveillance of superficial infections yielded 64 cultures with GAS, chiefly on the skin, including 51 (80%) of type emm74. An analysis of the social networks revealed the large number and variety of resources for the homeless used by the cases. Visits to the community organizations providing homeless services revealed the heterogeneity and precariousness of some of these services, the difficulties encountered in applying adequate health and hygiene measures, and the high degree of mobility amongst those who use these services.

Conclusion

The detection and control of iGAS outbreaks in both long-term care establishments and among community organizations providing homeless services are very complex. An outbreak of iGAS can develop in the background over a long time and be easily overlooked despite cases being admitted to the hospital. Emm typing and systematic research of previous cases of iGAS are essential tools for the detection and characterization of outbreaks. Close cooperation among public health agencies, clinical teams, community organizations and laboratories is essential for proper monitoring and the reduction of GAS transmission in the community and health care settings.

Invasive group a streptococcal disease in nursing homes, Minnesota, 1995-2006

Nursing home residents are at high risk for invasive GAS disease; clusters are common.

Nursing home residents are at high risk for invasive group A streptococcal (GAS) disease, and clusters of cases in nursing homes are common.To characterize the epidemiologic features of invasive GAS disease in nursing homes, we conducted active, statewide, population- and laboratory-based surveillance in Minnesota from April 1995 through 2006. Of 1,858 invasive GAS disease cases, 134 (7%) occurred in nursing home residents; 34 of these cases were identified as part of 13 clusters. Recognizing cases of GAS disease in nursing homes posed challenges. Measures to ensure identification of case-patients as residents of specific nursing homes need to be included in standard guidelines for the prevention and control of invasive GAS disease in this setting.

Invasive group a streptococcal disease in nursing homes, Minnesota, 1995-2006

Nursing home residents are at high risk for invasive group A streptococcal (GAS) disease, and clusters of cases in nursing homes are common.To characterize the epidemiologic features of invasive GAS disease in nursing homes, we conducted active, statewide, population- and laboratory-based surveillance in Minnesota from April 1995 through 2006. Of 1,858 invasive GAS disease cases, 134 (7%) occurred in nursing home residents; 34 of these cases were identified as part of 13 clusters. Recognizing cases of GAS disease in nursing homes posed challenges. Measures to ensure identification of case-patients as residents of specific nursing homes need to be included in standard guidelines for the prevention and control of invasive GAS disease in this setting.

Group a streptococcal disease in long-term care facilities: descriptive epidemiology and potential control measures

Group A streptococci (GAS) are an important cause of severe, life-threatening illness among the elderly population, particularly those individuals residing in long-term care facilities (LTCFs). Outbreaks of GAS infection are potentially devastating in this vulnerable population and often require large-scale control efforts involving LTCF staff, public health officials, and infectious diseases practitioners. Although multiple outbreaks of GAS infection in LTCFs have been described in the medical literature, this topic has not been reviewed for 15 years, and there is a need for updated guidance on how to approach GAS infection outbreak control. We reviewed published documents on GAS infection in LTCFs to describe the current understanding of the disease's epidemiology in this setting, identify techniques for outbreak investigation and prevention, and expose areas where additional research is needed. We highlight well-accepted prevention and control strategies that can be employed during investigation and control of GAS infection outbreaks in LTCFs.

An outbreak of noninvasive group A streptococcal disease in a facility for the developmentally disabled

BACKGROUND

Reports of outbreaks of group A streptococcal disease in long-term care facilities are uncommon.

METHODS

An outbreak of noninvasive group A streptococcal disease was investigated in a large facility for the developmentally disabled. The antistreptolysin O test was used to supplement the case finding.

RESULTS

Sixty-seven cases of streptococcal pharyngitis were diagnosed among residents and staff of the facility. Interventions based on enhanced infection control practices were effective, but maintaining them for several months was challenging because of the large number of staff, cognitive deficits of the residents, inconveniently placed areas for hand sanitation for the staff, and occurrence of a simultaneous outbreak of impetigo in the same population. After 4 months, the outbreak was successfully managed without chemoprophylaxis of the entire residential population and staff.

CONCLUSION

Outbreaks of group A streptococcal disease in centers for persons with developmental disabilities have unique challenges superimposed on routine outbreak response measures.