Pseudomonas (formerly Flavimonas) oryzihabitans is an uncommon pathogen that may cause catheter-associated infections. Although it has occasionally been isolated from the environment, the source of human infection has not previously been documented. We describe an AIDS patient who developed Pseudomonas oryzihabitans bacteremia due to colonization of a Hickman catheter. The patient reported having strictly followed the recommendations for catheter hygiene. The only flaw detected was the use of a synthetic bath sponge in the shower. The sponge was cultured and yielded P. oryzihabitans among other nonfermentative, gram-negative bacilli. To determine the prevalence of P. oryzihabitans in sponges, we cultured 15 samples from unrelated households. The microorganism was isolated from 3 of the 15 samples. Molecular typing by arbitrarily primed PCR (AP-PCR) was performed with the environmental and clinical isolates. Three different profiles were obtained for the six isolates analyzed from the patient's sponge. The strain from the AIDS patient was identical to one of those from his sponge and was different from all the remaining strains. The AP-PCR typing results were subsequently confirmed by pulsed-field gel electrophoresis. It can be concluded that sponges are occasionally colonized by P. oryzihabitans. For the first time a probable source of an indwelling catheter contamination with this bacterium has been found. Patients carrying these devices should avoid using sponge-like materials, as these are suitable environments for nonfermentative, gram-negative bacilli.