Toxic Shock Syndrome, 2006
Surveillance for staphylococcal toxic shock syndrome (STSS) over much of the last 20 years has been passive, relying on infection control and health care providers to notify MDH and report the syndrome. This system is limited particularly for STSS due to the complexity of confirming the diagnosis. Recently, there have been more strains of Staphylococcus aureus isolated carrying the toxin which can lead to STSS. In particular, strains of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) are known to cause STSS and have rapidly become prevalent in healthy children and adults. No change had been observed in the number of passively reported cases over the last few years, including in 2006, with three to six cases reported annually in the metropolitan area (seven statewide in 2006). In order to identify if there was a true increase in the incidence of STSS, MDH began a retrospective review to identify cases of STSS hospitalized during 2000-2003 in the metropolitan area.
Forty-three cases of STSS were identified in the surveillance area, with 23 cases related to menstruation (menstrual) and 20 cases unrelated to menstruation (nonmenstrual). The median age was 23.2 years (range, 1.4 to 81.0 years). Thirty-two (74%) of the 43 STSS cases had at least one positive culture for Staphylococcus aureus, including three (7%) with MRSA. Of the 22 menstrual cases with tampon use documented, 21 (95%) were using tampons at the onset of their first STSS related symptom. Of the 20 nonmenstrual cases, 10 (50%) had a skin or soft tissue site of infection, of which four were following a surgical procedure. Additionally, seven (42%) had no primary source identified after a median of four (range, one to six) sites cultured, two had multiple positive culture sites, and one had a pulmonary primary site.
The average yearly incidence was 0.52 cases per 100,000 with a 95% confidence interval (CI) of 0.32-0.77 for all ages. For menstrual related cases aged 13-24 years, the yearly incidence was 1.41 (95% CI, 0.63-2.61), but lower among menstrual cases aged 25-54 years at 0.43 (95% CI, 0.19-0.82). Among all nonmenstrual cases the incidence was 0.32 (95% CI, 0.12-0.67). These incidence rates are consistent with previous population-based estimates for STSS. We identified an increase in the incidence of menstrual STSS among ages 13-24 years during 2000-2003 (<0.1 to 2.3, p=.02) but a decrease in the incidence of menstrual STSS among females aged 25-54 years (1.0 to 0.2, p=0.01). From the 43 cases of STSS identified, 15 of 23 (65%) menstrual cases and three of 20 (15%) nonmenstrual cases were reported to MDH.
Currently, MDH is reviewing cases of possible STSS from 2004-06 to identify if there is a continued increasing trend in the incidence of menstrual STSS cases aged 13-24 years. Reporting of STSS continues to be a challenge, especially for nonmenstrual cases. STSS cases should be reported as they are identified.