This "opportunistic pathogen," as described by one team of microbiologists, works its way into a wide variety of settings. It requires little nutrition and can tolerate a range of settings, from hospital equipment and sinks, to community pools and even your talking device. In a study of 400 cell phones, Nigerian researchers found the bacteria were among the most common lurking on the gadgets [sources: Lister et al., Akinyemi].
What separates Pseudomonas aeruginosa from other items on this list is its amazing ability to resist treatment after infection. The more severe of these infections typically occur in hospitals and particularly among intensive care patients [source: Lister et al.]. That sounds like a good enough reason to make the ICU a cell-phone-free zone.