At least two otherwise healthy men appear to have acquired a rare bacterial skin infection that is hard to treat with antibiotics after receiving tattoos at a parlor in Seattle in the state of Washington in the US, according to a report in the Emerging Infectious Diseases journal that was e-published ahead of print on 10 August by the Centers for Disease Control and Prevention (CDC). Although no evidence was found to link the use of tap water to the infections, the report authors recommend that tattoo operators avoid using tap water and use sterilized water throughout their procedures.

One case is confirmed, the other is as yet unconfirmed say the CDC. The confirmed case is of a healthy 44-year-old man who received a tattoo on his left forearm at a commercial tattoo parlor in August 2009. He has tested positive for Mycobacterium haemophilum, a bacterium that rarely affects people with a healthy immune system, write lead author Meagan K. Kay of the CDC in Atlanta, and colleagues.

The yet to be confirmed case is of a healthy 35-year-old man who received his tattoo at the same parlor two months later. His tests were inconclusive, and the CDC are treating him as a “suspected” case of infection.

The authors write that although rare, difficult-to-treat bacterial infections have been reported even in healthy people who receive tattoos.

In the case of the man with the confirmed Mycobacterium haemophilum infection, he developed a painless rash at the tattoo site three days after visiting the parlor in August 2009. 12 days later he sought medical help. By then the rash had developed into bumpy, red nodules with pus (erythematous nodules) about 3 to 5 mm in diameter. By the following February, after several visits and treatment with various antibiotics, the rash eventually improved although some traces of infection remained. The man stopped treatment in March because of nausea, and by May the lesions had healed.

The source of the bacteria has not been traced. An investigation of the tattoo parlor by local authorities in December 2009 found all the procedures complied with Washington State safety and sanitation standards, although they did instruct the owner to switch to sterilized water instead of tap water for rinse solutions and diluting tattoo dyes.

None of the samples taken from various sites in the parlor, including the source of tap water, the tip of a reusable black ink container, various bits of equipment, the soap dispenser, and so on, showed traces of mycobacteria when tested by the CDC.

However, the authors note that although water has been suspected as a reservoir for M. haemophilum for various reasons, when investigators come to test environmental samples, using culture tests, as in this case, they are usually negative. They suggest that perhaps the interval of more than four months between the man visiting the parlor and the local authority investigation further reduced the chance of recovering any M. haemophilum.

They suggest tattoo operators probably use tap water because:

“No tattoo industry standards exist for the practice of diluting tattoo ink. Washington State does not specifically require tattoo artists to use steam-distilled or sterile water when rinsing needles or diluting ink.”

But they refer to legislation, brought in in July 2010, that “prohibits mixing ink and pigments with improper ingredients”.

So their conclusion, and recommendation is that despite the fact infections due to water appear uncommon, operators should not use tap water for for tattoo procedures.

Written by Catharine Paddock PhD