Atypical Mycobacterium: A New Risk?

Do you use tap water to cut your tattoo ink?  The Centers for Disease Control (CDC) now warns this may be a dangerous practice after a rare infection developed in two customers receiving tattoos at a professional tattoo shop in Washington State.

The cause of the infection was Mycobacterium haemophilum, a relative of the bacteria that causes tuberculosis.  It was believed the infection was acquired from the tap water the tattoo artist used to cut their tattoo ink.

Case 1

In August of 2009, a 44 year old man developed a painless rash at the site of his tattoo he had received three days earlier on his left forearm.  The rash did not resolve with antibacterial ointment and 12 days later the patient went to see his health care provider.

The patient was treated with a cocktail of antibiotics that should have treated the usual suspects including staph, strep, and MRSA.  Aerobic wound cultures were obtained and showed no growth.  The following month the patient still had no improvement and was treated with an extended antibiotic course and again negative wound cultures were obtained.  Again there was no improvement and an expanded work up was conducted that included testing for hepatitis B and C viruses, and HIV, all of which were negative.  Specialized wound cultures were performed and identified the presence of Mycobacterium haemophilum.  The patient was then treated for several months with antibiotics to which the particular bacteria was found to be sensitive and ultimately the patient recovered nine months after the start of the infection.

Case 2

In October 2009, the same health care provider saw a similar infection also in a tattoo from the same tattoo parlor.  All cultures including Mycobaterium cultures were negative, but the patient was empirically managed as another likely case of Mycobacterium given the similar appearance .

Public Health Response

The Seattle and King County Public Health Departments asked physicians to report atypical skin infections developed amongst tattoo recipients between June 1st, 2009 to December 1st, 2009 and also asked clinical laboratories to report any atypical Mycobacterium species discovered during the same time period.  No additional cases were identified.

The tattoo shop was investigated on December 10th, 2009.  The shop was found to be in compliance with the Washington State safety and sanitation standards.  Eleven samples were collected from the shop and sent to the CDC for further testing, including the tattoo ink, tap water, liquid soap, petroleum jelly, and swabs of the equipment, soap dispenser port, and the tip of a reusable black tattoo ink container.  All the materials sent to the CDC tested negative for bacterial contamination.  Suspicion focused on the tap water however and the tattoo shop was instructed henceforth to use only sterile water for rinse solutions and for the dilution of tattoo dye.

Discussion

What is Mycobacterium haemophilum?

Mycobacterium haemophilum belongs to the same genus as the bacterium that causes tuberculosis.  Consequently, non-tuberculin Mycobacterium are often collectively called "atypical" Mycobacterium.  Mycobacterium are very difficult to culture and require special testing and very long culture times to identify.  This explains why it was missed on multiple initial cultures performed in the first case.  Species of Mycobacterium are "fastidious" meaning "difficult to please," requiring specialized growth media and testing to identify and  can be very difficult to isolate.  Consequently, the decision to treat the second patient for Mycobacterium infection was appropriate, although less gratifying as a case study since there was no clear proof this patient had the same infection.  The inability to culture Mycobacterium from a wound infected by Mycobacterium is very common however, and the length of time the patient in case one was infected increased the chance of obtaining a positive culture. 

Why is the Tap Water the Prime Suspect?

Non-Tuberculosis Mycobacteria (NTM) are known to exist in potable water and are resistant to many of the standard techniques to sterilize tap water for drinking.  Entry into the skin via surgical wounds or abraded skin have long been known to be routes of infection.  The use of tap water into a skin wound such as a fresh tattoo is a plausible mechanism of infection.  The act of tattooing with contaminated tap water would be the most likely cause, but the investigation failed to prove this point; although less likely, it is possible that the tattoo became infected through other mechanisms.

My Two Cents

Tap water doesn't belong under the skin.  Although these cases of Mycobacterial infections are obviously very rare, they illustrate what we have known in medicine for quite some time: things that aren't sterile don't belong under the skin.  Although municipal water supplies are generally safe, having been treated with chemicals such as chlorine to kill bacteria, they aren't sterile.  Most healthy adults with working immune systems don't become ill after ingesting water with low bacterial burdens as our stomach acid and innate immunity in our gut becomes a line of defense.  Breaching that line of defense by injecting materials directly into the body exposes us to potential bacterial contamination.  Since Mycobacteria are so difficult to culture, we may never know what the true source of these infections were.  Since tattoo inks are not regulated, there are no sterilization validations that exist for tattoo inks either.  We can only hope that the ink manufacturers are exercising due diligence when it comes to sterile manufacturing of these products.  In the meantime, it may be prudent to use only sterile water when diluting tattoo ink.   

References:

Kay MK, Perti TR, Duchin JS. Tattoo-associated Mycobacterium haemophilum skin infection in immunocompetent adult, 2009. Emerg Infect Dis. 2011 Sep; [Epub ahead of print]

MYCOBACTERIA: DRINKING WATER FACT SHEET, EPA-822-F-02-002, March 2002.