TABLE 1.
Prevalence of samples that have ESC, ESBL, and non-ESBL phenotypes and mean (log10) and median enhanced conjugation frequency estimated for all samples and when stratified by processing stage and seasona
| Stratification parameters | % of samples with phenotype (95% CI) |
Mean log10 conjugation frequency (95% CI) | Conjugation frequency (interquartile range) | ||
|---|---|---|---|---|---|
| ESCb | ESBLc | Non-ESBLd | |||
| Processing stage | |||||
| Digested (n = 63) | 57.1 (44.0, 69.5) | 44.4 (31.9, 57.5) | 19.0 (10.2, 30.9) | −7.6 (−8.3, −7.0) | 0 (0, 2 × 10−6) |
| Raw (n = 63) | 82.5 (70.9, 90.9) | 60.3 (47.2, 72.4) | 33.3 (22.0, 46.3) | −6.8 (−7.5, −6.1) | 8.0 × 10−8 (0, 1.9 × 10−5) |
| Season | |||||
| Spring (n = 50) | 56.0 (41.3, 70.0) | 36.0 (22.9, 50.8) | 24.0 (13.1, 38.2) | −7.8 (−8.5, −7.1) | 0 (0, 7.5 × 10−7) |
| Summer (n = 30) | 83.3 (65.3, 94.4) | 66.7 (47.2, 82.7) | 30.0 (14.7, 49.4) | −6.9 (−7.9, −6.0) | 5.4 × 10−8 (0, 1.2 × 10−5) |
| Fall (n = 12) | 75.0 (42.8, 94.5) | 58.3 (27.7, 84.8) | 33.3 (9.9, 65.1) | −7.1 (−8.6, −5.6) | 1.2 × 10−7 (0, 1.7 × 10−5) |
| Winter (n = 34) | 76.5 (58.8, 89.3) | 61.8 (43.6, 77.8) | 23.5 (10.7, 41.2) | −6.7 (−7.6, −5.7) | 6.9 × 10−7 (0, 1.9 × 10−5) |
| Overall (n = 126) | 69.8 (61.0, 77.7) | 52.4 (43.3, 61.3) | 26.2 (18.8, 34.8) | −7.2 (−7.7, −6.8) | 2.3 × 10−9 (0, 8.0 × 10−6) |
a
Phenotypes of transconjugants were determined by ESBL confirmation assay and binned into either ESBL or non-ESBL phenotypes.
b
ESC, samples yielding transconjugants of any phenotypes (ESBL, non-ESBL, or both phenotypes). CI, confidence interval.
c
ESBL, samples yielding ESBL phenotype transconjugants.
d
Non-ESBL, samples yielding non-ESBL phenotype transconjugants.