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.

The epidemiology of invasive group A streptococcal infection and potential vaccine implications: United States, 2000-2004

BACKGROUND

Invasive group A Streptococcus (GAS) infection causes significant morbidity and mortality in the United States. We report the current epidemiologic characteristics of invasive GAS infections and estimate the potential impact of a multivalent GAS vaccine.

METHODS

From January 2000 through December 2004, we collected data from Centers for Disease Control and Prevention's Active Bacterial Core surveillance (ABCs), a population-based system operating at 10 US sites (2004 population, 29.7 million). We defined a case of invasive GAS disease as isolation of GAS from a normally sterile site or from a wound specimen obtained from a patient with necrotizing fasciitis or streptococcal toxic shock syndrome in a surveillance area resident. All available isolates were emm typed. We used US census data to calculate rates and to make age- and race-adjusted national projections.

RESULTS

We identified 5400 cases of invasive GAS infection (3.5 cases per 100,000 persons), with 735 deaths (case-fatality rate, 13.7%). Case-fatality rates for streptococcal toxic shock syndrome and necrotizing fasciitis were 36% and 24%, respectively. Incidences were highest among elderly persons (9.4 cases per 100,000 persons), infants (5.3 cases per 100,000 persons), and black persons (4.7 cases per 100,000 persons) and were stable over time. We estimate that 8950-11,500 cases of invasive GAS infection occur in the United States annually, resulting in 1050-1850 deaths. The emm types in a proposed 26-valent vaccine accounted for 79% of all cases and deaths. Independent factors associated with death include increasing age; having streptococcal toxic shock syndrome, meningitis, necrotizing fasciitis, pneumonia, or bacteremia; and having emm types 1, 3, or 12.

CONCLUSIONS

GAS remains an important cause of severe disease in the United States. The introduction of a vaccine could significantly reduce morbidity and mortality due to these infections.

Performance of a rapid dermatology referral system during the anthrax outbreak

The bioterrorism-related anthrax outbreak generated unanticipated demand for dermatologic services. In this study we sought to perform rapid, efficient, cost-effective evaluation of patients suspected of having cutaneous anthrax. During the outbreak, we developed an anthrax evaluation system featuring clinical field examination by nondermatologist physicians, followed by rapid referral of selected high-risk patients to a centralized dermatology center. We excluded anthrax in 29 previously screened high-risk patients. All were examined within 24 hours, costing $272.07 per patient. Diagnoses were established quickly (median, same day; range, 0-15 days). Among 2259 at-risk postal workers, 144 (6.4%) self-identified new (< or =14 days) skin lesions and were examined in the field; 8 (5.6%) were referred to our system. Our system was not the only local dermatologic resource available during the outbreak. A system featuring initial nondermatologist examination with minimal laboratory evaluation, followed by rapid centralized referral of high-risk patients, functioned efficiently in this outbreak.

SARS surveillance during emergency public health response, United States, March-July 2003

In response to the emergence of severe acute respiratory syndrome (SARS), the United States established national surveillance using a sensitive case definition incorporating clinical, epidemiologic, and laboratory criteria. Of 1,460 unexplained respiratory illnesses reported by state and local health departments to the Centers for Disease Control and Prevention from March 17 to July 30, 2003, a total of 398 (27%) met clinical and epidemiologic SARS case criteria. Of these, 72 (18%) were probable cases with radiographic evidence of pneumonia. Eight (2%) were laboratory-confirmed SARS-coronavirus (SARS-CoV) infections, 206 (52%) were SARS-CoV negative, and 184 (46%) had undetermined SARS-CoV status because of missing convalescent-phase serum specimens. Thirty-one percent (124/398) of case-patients were hospitalized; none died. Travel was the most common epidemiologic link (329/398, 83%), and mainland China was the affected area most commonly visited. One case of possible household transmission was reported, and no laboratory-confirmed infections occurred among healthcare workers. Successes and limitations of this emergency surveillance can guide preparations for future outbreaks of SARS or respiratory diseases of unknown etiology.

Risk for severe group A streptococcal disease among patients' household contacts

From January 1997 to April 1999, we determined attack rates for cases of invasive group A streptococcal (GAS) disease in household contacts of index patients using data from Active Bacterial Core Surveillance sites. Of 680 eligible index-patient households, 525 (77.2%) were enrolled in surveillance. Of 1,514 household contacts surveyed, 127 (8.4%) sought medical care, 24 (1.6%) required hospital care, and none died during the 30-day reference period. One confirmed GAS case in a household contact was reported (attack rate, 66.1/100,000 household contacts). One household contact had severe GAS-compatible illness without confirmed etiology. Our study suggests that subsequent cases of invasive GAS disease can occur, albeit rarely. The risk estimate from this study is important for developing recommendations on the use of chemoprophylaxis for household contacts of persons with invasive GAS disease.

Population-based surveillance for postpartum invasive group a streptococcus infections, 1995-2000

Estimates of disease burden and data on the sources of invasive postpartum group A streptococcus (GAS) infections will help guide public health action. Active, population-based surveillance was conducted in 9 regions from 1995 through 2000. A case of GAS infection was defined as isolation of GAS from a sterile site in a resident of a surveillance area who was pregnant or in the postpartum period. Census and live birth data were used to calculate rates. Eighty-seven cases of postpartum GAS infection (2.2% of 3957 invasive GAS infections) occurred at 3%-8% of hospitals annually. We estimate that 220 cases occurred annually in the United States. Two or more cases were noted during 6 months at 8 hospitals, during 1 year at 13 hospitals, and during 2 years at 16 hospitals. Cases due to identical emm types clustered more frequently than expected by chance. Although postpartum GAS infections are rare, the clustering of infections due to identical strains suggests that some invasive cases may have a common source and, therefore, may be preventable.