Exposure to UV radiation is associated with skin aging, wrinkle production, liver spots, loss of skin elasticity, erythema (reddening of the skin), sunburn, photokeratitis (snow blindness), ocular melanoma (eye cancer), and infections. Tanning beds can contain many microbes, some of which are pathogens that can cause skin infections and gastric distress. In one study in New York in 2009, the most common pathogens found on tanning beds were Pseudomonas spp. (aeruginosa and putida), Bacillus spp., Klebsiella pneumoniae, Enterococcus species, Staphylococcus aureus, and Enterobacter cloacae. Several prescription and over-the-counter drugs, including antidepressants, antibiotics, antifungals and anti-diabetic medication, can cause photosensitivity, which makes burning the skin while tanning more likely. This risk is increased by a lack of staff training in tanning facilities.