Table 2.
Risk factors for ceftriaxone resistance among urinary Escherichia coli isolates
| Characteristic | Proportion ceftriaxone resistant | Risk ratio (95% CI)* | Adjusted risk ratio (95% CI)† |
|---|---|---|---|
| Sex | |||
| Female | 5.5% (331/6008) | reference | reference |
| Male | 7% (51/724) | 1.28 (0.96–1.70) | 1.17 (0.88–1.55) |
| Age group | |||
| 80 years and more | 6.4% (72/1119) | reference | reference |
| 70–79 years | 6.3% (66/1048) | 0.98 (0.71–1.35) | 1.22 (0.87–1.70) |
| 60–69 years | 5.4% (48/890) | 0.84 (0.59–1.19) | 1.12 (0.77–1.63) |
| 50–59 years | 5.6% (42/751) | 0.87 (0.60–1.26) | 1.20 (0.81–1.78) |
| 40–49 years | 3.9% (26/659) | 0.61 (0.40–0.95) | 0.84 (0.53–1.34) |
| 30–39 years | 5.3% (39/734) | 0.83 (0.57–1.21) | 1.05 (0.70–1.59) |
| 20–29 years | 6.9% (58/846) | 1.07 (0.76–1.49) | 1.48 (1.02–2.15) |
| 15–19 years | 3.3% (8/246) | 0.51 (0.25–1.04) | 0.77 (0.37–1.61) |
| 10–14 years | 2.8% (2/72) | 0.43 (0.11–1.72) | 0.66 (0.17–2.61) |
| 5–9 years | 4.1% (8/194) | 0.64 (0.31–1.31) | 0.98 (0.47–2.02) |
| 0–4 years | 7.6% (13/170) | 1.19 (0.67–2.10) | 1.71 (0.95–3.07) |
| Residence in RACF | |||
| No | 5.3% (337/6397) | reference | reference |
| Yes | 13.4% (45/335) | 2.55 (1.91–3.41) | 2.94 (2.10–4.13) |
| Referral source | |||
| Community | 5.4% (332/6095) | reference | reference |
| Hospital: ED | 4.2% (15/358) | 0.77 (0.46–1.28) | 0.72 (0.43–1.21) |
| Hospital: non-ED | 12.5% (35/279) | 2.30 (1.66–3.19) | 2.05 (1.45–2.9) |
| Region | |||
| Western Metropolitan | 7.9% (78/982) | reference | reference |
| Northern Metropolitan | 8.8% (59/672) | 1.11 (0.80–1.53) | |
| Eastern Metropolitan | 6.6% (47/710) | 0.83 (0.59–1.18) | |
| South-Eastern Metropolitan | 7.1% (70/981) | 0.90 (0.66–1.23) | |
| Southern Metropolitan | 4.2% (28/660) | 0.53 (0.35–0.81) | |
| Northern Victoria | 3.7% (28/763) | 0.46 (0.30–0.70) | |
| Eastern Victoria | 5.2% (51/973) | 0.66 (0.47–0.93) | |
| Western Victoria | 2.2% (6/270) | 0.28 (0.12–0.63) | |
| Other | 2.1% (15/714) | 0.26 (0.15–0.46) | |
| Remoteness area | |||
| Major Cities | 6.3% (330/5267) | reference | |
| Inner Regional | 3.5% (44/1268) | 0.55 (0.41–0.75) | 0.89 (0.60–1.30) |
| Other | 4.2% (8/191) | 0.67 (0.34–1.33) | 1.13 (0.56–2.31) |
| Index of Relative Socio-economic Disadvantage, 1st decile | |||
| No | 5.4% (332/6120) | reference | |
| Yes | 8.3% (49/591) | 1.53 (1.15–2.04) | 0.93 (0.65–1.31) |
| Percentage of postcode residents born in region, median (IQR)‡ | |||
| Oceania and Antarctica | NA | 0.89 0.86–0.92) | |
| North-West Europe | NA | 0.62 (0.49–0.77) | |
| Southern and Eastern Europe | NA | 1.39 (1.23–1.57) | 1.12 (0.94–1.32) |
| North Africa and the Middle East | NA | 1.47 (1.31–1.65) | 1.30 (1.09–1.54) |
| South-East Asia | NA | 1.24 (1.16–1.33) | 1.14 (1.02–1.27) |
| North-East Asia | NA | 1.09 (1.01–1.19) | 0.99 (0.89–1.11) |
| Southern and Central Asia | NA | 1.29 (1.20–1.38) | 1.16 (1.04–1.28) |
| Americas | NA | 1.76 (0.49–6.33) | |
| Sub-Saharan Africa | NA | 2.02 (1.02–3.99) | 1.55 (0.66–3.65) |
Notes: *From univariable Poisson regression models; †From multivariable Poisson regression model (23 records omitted due to missing values); ‡ Effect measure corresponds to the change in prevalence of ceftriaxone resistance for each 5% increase in proportion of residents born in specified region. ED = emergency department; IQR = interquartile range; RACF = residential aged-care facility