Table 4.
Number of patients colonized (includes only patients with admission in study period) and maximum likelihood estimators for the acquisition parameters α (endogenous acquisition) and β (exogenous acquisition) and related quantities, for all pathogens under study (using data obtained from all patients present on ward during study period), in year 1 and year 2
| Year 1 N = 190 |
Year 2 N = 167 |
P valuea | |
|---|---|---|---|
|
Methicillin-resistant Staphylococcus aureus | |||
| Patients with a positive culture—no./total no. (%) | 44/174 (25.3) | 19/161 (11.8) | |
| Patients with a positive culture on admission—no./total no. (%) | 5/174 (2.9) | 4/161 (2.5) | 0.83 |
| Acquisition parameter α—MLE (95 % CI) | 0.005 (0.002; 0.012) | 0.005 (0.002; 0.009) | |
| Acquisition parameter β—MLE (95 % CI) | 0.117 (0.079; 0.162) | 0.015 (0.0; 0.055) | |
| Estimated daily prevalence—% (95 % CI) | 34.0 (33.9; 34.2) | 10.3 (10.26; 10.31) | |
| Acquisitions—estimated no. (95 % CI) | 53.7 (51.8; 55.8) | 18.8 (18.1; 19.8) | |
| Exogenous acquisitions—estimated % of total no. of acquisitions (95 % CI) | 83.7 (69.1; 90.9) | 21.7 (0; 55.5) | |
| ESBL-positive Enterobacteriaceae (excl. K. pneumoniae) | |||
| Patients with a positive culture–no./total no. (%) | 94/174 (54.0) | 90/161 (55.9) | |
| Patients with a positive culture on admission—no./total no. (%) | 22/174 (12.6) | 10/161 (6.2) | 0.04 |
| Acquisition parameter α—MLE (95 % CI) | 0.086 (0.043; 0.107) | 0.020 (0; 0.059) | |
| Acquisition parameter β—MLE (95 % CI) | 0 (0.0; 0.085) | 0.105 (0.024; 0.0173) | |
| Estimated daily prevalence—% (95 % CI) | 61.3 (61.1; 61.5) | 55.0 (54.9; 55.0) | |
| Acquisitions—estimated no. (95 % CI) | 86.5 (84.4; 88.7) | 100.2 (98.8; 101.8) | |
| Exogenous acquisitions—estimated % of total no. of acquisitions (95 % CI) | 0 (0; 48.2) | 70.8 (17.0; 100.0) | |
| Pseudomonas aeruginosa | |||
| Patients with a positive culture—no./total no. (%) | 66/174 (37.9) | 95/161 (59) | |
| Patients with a positive culture on admission—no./total no. (%) | 7/174 (4.0) | 9/161 (5.6) | 0.5 |
| Acquisition parameter α—MLE (95 % CI) | 0.042 (0.01; 0.073) | 0.085 (0.026; 0.119) | |
| Acquisition parameter β—MLE (95 % CI) | 0.037 (0; 0.114) | 0.026 (0; 0.132) | |
| Estimated daily prevalence—% (95 % CI) | 53.4 (53.2; 53.7) | 66.4 (66.3; 66.5) | |
| Acquisitions—estimated no. (95 % CI) | 71.3 (68.8; 74.1) | 107.6 (105.8; 109.6) | |
| Exogenous acquisitions—estimated % of total no. of acquisitions (95 % CI) | 28.8 (0; 81.5) | 15.1 (0; 74.0) | |
|
Gentamicin-resistant Klebsiella pneumoniae | |||
| Patients with a positive culture—no./total no. (%) | 86/174 (49.4) | 92/161 (57.1) | |
| Patients with a positive culture on admission—no./total no. (%) | 19/174 (10.9) | 15/161 (9.3) | 0.63 |
| Acquisition parameter α—MLE (95 % CI) | 0.102 (0.049; 0.119) | 0.075 (0.031; 0.091) | |
| Acquisition parameter β—MLE (95 % CI) | 0 (0; 0.094) | 0 (0; 0.087) | |
| Estimated daily prevalence—% (95 % CI) | 65.7 (65.4; 65.9) | 58.4 (58.4; 58.5) | |
| Acquisitions—estimated no. (95 % CI) | 90.3 (87.7; 93.1) | 100.9 (99.6; 102.5) | |
| Exogenous acquisitions—estimated % of total no. of acquisitions (95 % CI) | 0 (0; 49.8) | 0 (0; 57.7) | |
| Amikacin-resistant Acinetobacter species | |||
| Patients with a positive culture—no./total no. (%) | 85/174 (48.9) | 89/161 (55.3) | |
| Patients with a positive culture on admission—no./total no. (%) | 21/174 (12.1) | 7/161 (4.3) | 0.01 |
| Acquisition parameter α—MLE (95 % CI) | 0.047 (0.014; 0.090) | 0.066 (0.005; 0.096) | |
| Acquisition parameter β—MLE (95 % CI) | 0.067 (0; 0.147) | 0.025 (0; 0.143) | |
| Estimated daily prevalence—% (95 % CI) | 57.1 (56.9.7; 57.2) | 60.2 (60.1; 60.3) | |
| Acquisitions—estimated no. (95 % CI) | 86.9 (84.8; 89.4) | 102.5 (100.8; 104.3) | |
| Exogenous acquisitions—estimated % of total no. of acquisitions (95% CI) | 39.8 (0; 80.4) | 17.0 (0; 93.6) | |
MLE maximum likelihood estimate
aDetermined using χ 2 test for independent observations only