Table 2.
Incidence of Invasive Staphylococcus aureus Disease by Age, Type of Infection, and Antibiotic Resistance, May 2016–April 2018
| Category | Year 1 (May 2016–Apr 2017) | Year 2 (May 2017–Apr 2018) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| No. SA Cases | No. MRSA Cases | Populationa | Incidence of SAb (95% CI) | Incidence of MRSAb (95% CI) | No. SA Cases | No. MRSA Cases | Populationa | Incidence of SAb (95% CI) | Incidence of MRSAb (95% CI) | |
| Overall | 24 | 18 | 16 965 | 141.5 (94.8–211.1) | 106.1 (66.9–168.4) | 29 | 22 | 16 948 | 171.1 (118.9–246.2) | 129.8 (85.5–197.1) |
| Age (Years) | ||||||||||
| <1 | 0 | 0 | 323 | 0 | 0 | 0 | 0 | 339 | 0 | 0 |
| 1–17 | 2 | 2 | 5709 | 35.0 (8.8–140.1) | 35.0 (8.8–140.1) | 3 | 2 | 5720 | 52.5 (16.9–162.6) | 35.0 (8.8–139.8) |
| 18–39 | 6 | 5 | 5597 | 107.2 (48.2–238.6) | 89.3 (37.2–214.6) | 9 | 7 | 5465 | 164.7 (85.7–316.3) | 128.1 (61.1–268.6) |
| 40–49 | 5 | 3 | 1651 | 302.8 (126.1–727.6) | 181.7 (58.6–563.4) | 6 | 5 | 1795 | 334.3 (150.4–743.1) | 278.6 (116.1–668.4) |
| 50–64 | 10 | 7 | 2477 | 403.7 (217.2–750.3) | 282.6 (592.8) | 10 | 7 | 2383 | 419.6 (226.1–778.9) | 293.8 (140.2–615.5) |
| ≥65 | 1 | 1 | 1208 | 82.8 (11.7–587.7) | 82.8 (11.7–587.7) | 1 | 1 | 1246 | 80.3 (11.3–569.3) | 80.3 (11.3–569.3) |
| Type of Infection | ||||||||||
| CA | 9 | 6 | 16 965 | 53.1 (27.6–102.0) | 35.4 (15.9–78.7) | 5 | 3 | 16 948 | 29.5 (12.3–70.9) | 17.7 (5.7–54.9) |
| HACO | 15 | 15 | 16 965 | 88.4 (53.3–146.7) | 88.4 (53.3–146.7) | 23 | 18 | 16 948 | 135.7 (9.0–204.2) | 106.2 (66.9–168.5) |
| HO | 0 | 0 | 16 965 | 0 | 1 | 1 | 16 948 | 5.9 (0.8–41.9) | 5.9 (0.8–41.9) | |
| Antibiotic Resistance | ||||||||||
| MSSA | 6 | n/a | 16 965 | 35.4 (15.9–78.7) | n/a | 7 | n/a | 16 948 | 41.3 (19.7–86.6) | n/a |
| MRSA | 18 | n/a | 16 965 | 106.1 (66.9–168.4) | n/a | 22 | n/a | 16 948 | 129.8 (85.5–197.1) | n/a |
Abbreviations: CA, community-associated; CI, confidence interval; HACO, healthcare-associated community-onset; HO, hospital-onset; MRSA, methicillin-resistant Staphylococcus aureus; MSSA, methicillin-susceptible Staphylococcus aureus; n/a, not applicable; SA, Staphylococcus aureus.
aIndian Health Service User Population from 2016 (Year 1) and 2017 (Year 2).
bPer 100 000 person.