Molecular epidemiologic features and antimicrobial susceptibility profilesof various ribotypes of Pseudomonas aeruginosa isolated from humans and ruminants

Objectives-To assess automated ribotyping for characterization of Pseudomon as aeruginosa isolates and to identify their type prevalence and geographic distribution. Sample Population-39 human and 56 ruminant P aeruginosa isolates. Procedures-Isolates were identified by use of bacteriologic techniques and automated Pvull-based ribotyping. Susceptibility to antimicrobials was test ed in vitro. Data were analyzed for index of discrimination; prevalence rat io; geographic distribution of ribotypes found only in humans, only in cows , or only in goats (single-host ribotypes); and geographic distribution of ribotypes found in humans and ruminants (multihost ribotypes). Results-All isolates were typeable (45 ribotypes, 35 single-host ribotypes) . Ribotyping index of discrimination was 0.976. More isolates (45.3%) than expected yielded multihost ribotypes (22% of all ribotypes). Although 8.6% of single-host ribotypes were found in 4 or more isolates, 60% of multihost ribotypes were found in 4 or more isolates. Ninety percent of multihost ri botypes were isolated from different geographic areas, whereas 3.0% of sing le-host ribotypes were isolated from different geographic areas. All rumina nt isolates were susceptible to gentamicin and polymyxin B. In contrast, an tibiogram profiles differed for human isolates from different geographic ar eas. Susceptibility to antimicrobials differentiated 6 isolates not disting uished by ribotyping. Conclusions and Clinical Relevance-Automated ribotypi ng with Pvull discriminated more isolates than in vitro antimicrobial susce ptibility. In combination, both tests provided more information than either test alone. Given the greater prevalence and geographic distribution of mu ltihost ribotypes, immunocompromised humans and lactating ruminants may hav e a greater risk for disease if exposed to multihost P aeruginosa ribotypes , compared with single-host ribotypes.