Nursing home outbreak of invasive group a streptococcal infections caused by 2 distinct strains.
OBJECTIVE
To identify factors contributing to a cluster of deaths from invasive group A streptococcus (GAS) infection in a nursing home facility and to prevent additional cases.


METHODS
Outbreak investigation.


METHODS
A 146-bed nursing home facility in northern Nevada.


METHODS
We defined a case as the isolation of GAS from a normally sterile site in a resident of nursing home A. To identify case patients, we reviewed resident records from nursing home A, the local hospital, and the hospital laboratory. We obtained oropharyngeal and skin lesion swabs from staff and residents to assess GAS colonization and performed emm typing on available isolates. To identify potential risk factors for transmission, we performed a cohort study and investigated concurrent illness among residents and surveyed staff regarding infection control practices.


RESULTS
Six residents met the case patient definition; 3 (50%) of them died. Among invasive GAS isolates available for analysis, 2 distinct strains were identified: emm11 (3 isolates) and emm89 (2 isolates). The rate of GAS carriage was 6% among residents and 4% among staff; carriage isolates were emm89 (8 isolates), emm11 (2 isolates), and emm1 (1 isolate). Concurrently, 35 (24%) of the residents developed a respiratory illness of unknown etiology; 41% of these persons died. Twenty-one (30%) of the surveyed employees did not always wash their hands before patient contacts, and 27 (38%) did not always wash their hands between patient contacts.


CONCLUSIONS
Concurrent respiratory illness likely contributed to an outbreak of invasive GAS infection from 2 strains in a highly susceptible population. This outbreak highlights the importance of appropriate infection control measures, including respiratory hygiene practices, in nursing home facilities.
Thigpen
Michael C
MC
Respiratory Diseases Branch, Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Atlanta, GA 30333, USA. mthigpen@cdc.gov
Thomas
D Michael
DM
Gloss
David
D
Park
Sarah Y
SY
Khan
Amy J
AJ
Fogelman
Vicky L
VL
Beall
Bernard
B
Van Beneden
Chris A
CA
Todd
Randall L
RL
Greene
Carolyn M
CM
D000368:Aged; D000369:Aged, 80 and over; D003428:Cross Infection / Q000453:epidemiology / Q000635:transmission; D004196:Disease Outbreaks; D005260:Female; D006707:Homes for the Aged / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D009735:Nursing Homes / Q000706:statistics & numerical data; D018410:Pneumonia, Bacterial / Q000453:epidemiology* / Q000635:transmission; D012307:Risk Factors; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000635:transmission; D013297:Streptococcus pyogenes / Q000145:classification* / Q000302:isolation & purification