TABLE 2.
Risk of MRSA and MSSA B/M Among 8444 VLBW Infants Who Survived >3 Days: NICHD NRN 2006–2008
| Characteristicsa | Total No. | Infants With MRSA, No. (%) | Adjusted RR for MRSA (95% CI)b | Infants With MSSA, No. (%) | Adjusted RR for MSSA (95% CI)b |
|---|---|---|---|---|---|
| Maternal antibiotic use during delivery admission | |||||
| Yes | 4916 | 56 (1.1) | 0.94 (0.58–1.53) | 118 (2.4) | 0.65 (0.49–0.87)d |
| No | 3395 | 32 (0.9) | Referencec | 106 (3.1) | Reference |
| Maternal steroid use before delivery | |||||
| Yes | 6806 | 74 (1.1) | 1.38 (0.72–2.64) | 187 (2.7) | 1.37 (0.95–1.99) |
| No | 1566 | 12 (0.8) | Reference | 41 (2.6) | Reference |
| Chorioamnionitis noted in mother’s medical record | |||||
| Yes | 1028 | 7 (0.7) | 0.50 (0.23–1.11) | 11 (1.1) | 0.31 (0.17–0.57)e |
| No | 7313 | 81 (1.1) | Reference | 216 (3.0) | Reference |
| Infant gender | |||||
| Boy | 4219 | 45 (1.1) | 1.05 (0.69–1.61) | 127 (3.0) | 1.21 (0.93–1.57) |
| Girl | 4225 | 43 (1.0) | Reference | 101 (2.4) | Reference |
| GA (wk) | |||||
| <25 | 1027 | 23 (2.2) | 5.60 (2.80–11.18)e | 52 (5.1) | 6.24 (3.94–9.91)e |
| 25–28 | 4162 | 52 (1.3) | 3.20 (1.73–5.93) | 145 (3.5) | 4.17 (2.80–6.20) |
| 29+ | 3253 | 13 (0.4) | Reference | 31 (1.0) | Reference |
| Race/ethnicity | |||||
| Non-Hispanic black | 3070 | 49 (1.6) | 1.08 (0.65–1.78) | 85 (2.8) | 1.17 (0.85–1.63) |
| Hispanic | 1518 | 9 (0.6) | 1·01 (0.45–2.27) | 48 (3.2) | 1.16 (0.79–1.70) |
| Other | 434 | 2 (0.5) | 0.84 (0.19–3.68) | 10 (2.3) | 1.03 (0.52–2.02) |
| Non-Hispanic white | 3391 | 28 (0.8) | Reference | 85 (2.5) | Reference |
| Congenital birth defect | |||||
| Yes | 395 | 5 (1.3) | 1.59 (0.64–3.95) | 11 (2.8) | 1.52 (0.83–2.80) |
| No | 8049 | 83 (1.0) | Reference | 217 (2.7) | Reference |
a
Information was missing for maternal antibiotic use: 133 infants; maternal steroid use: 72; chorioamnionitis: 103; GA: 2; race/ethnicity: 31.
b
RRs, CIs, and P values by the F test from Poisson regression models that included the variables shown and used data from the full cohort. One model was fit to the binary outcome MRSA, yes/no (for RRs associated with MRSA), and another to the binary outcome MSSA, yes/no (for RRs associated with MSSA). Variation between study centers was accounted for by treating center as a random effect.
c
All instances of reference refer to the comparison group.
d
P ≤ .01.
e
P ≤ .001.