Table 1.
Pseudomonas aeruginosa Isolates With Protease and Elastase Activity Are Common in the ICU
| PA Pathogen Characteristics | No. Samples (%) |
|---|---|
| Elastase activitya | |
| Any (>0%) | 178 (74.8) |
| Low (0%-50%) | 134 (56.3) |
| High (>50%) | 104 (43.7) |
| Protease activitya | |
| Any (>0%) | 170 (71.4) |
| Low (0%-50%) | 161 (67.7) |
| High (>50%) | 77 (32.3) |
| Biofilm productionb | 143 (60.6) |
| MDR/XDRc | 74 (31.6) |
| Polymicrobiald | 88 (37.5) |
P aeruginosa (PA) respiratory isolates were obtained from unique ICU patients admitted to the ICU at two academic medical referral centers. MDR = multidrug-resistant; XDR = extensively drug resistant.
Elastase and protease activity were normalized to a research PA reference strain (PA14) and reported as % elastase or protease activity: Any (>0%), Low (0%-50%), High (>50%). The elastase activity used fluorogenic elastin as a substrate, and protease activity used fluorogenic casein as the substrate. N = 238 for elastase activity. N = 238 for protease activity.
Biofilm production was measured using a crystal violet staining assay as described in the Methods section. n = 236 for biofilm production.
Multidrug or extensively drug resistant (MDR/XDR) was defined by resistance to ≥3 or ≥6 antibiotic classes, respectively, and were combined for the analysis. n = 234 for MDR/XDR status
Polymicrobial was defined as the presence of other pathogens from the same respiratory sample, n = 235 for polymicrobial.