Retrospective analysis of microbial contamination in tattoo and permanent makeup inks

Microbial contamination of tattoo and permanent makeup (PMU) inks poses a significant public health threat as these products are directly injected into the skin. Despite regulatory measures, outbreaks of ink-related infections persist. This study examined 259 unopened tattoo and PMU ink products from the past decade in the United States to assess contamination rates, microbial diversity, and associated health risks.

The overall prevalence of bacterial contamination in the surveyed inks was 35.4% (95% CI: 21.6–49.1%), with comparable rates for both tattoo and PMU inks (~33%). The contamination rates were not significantly influenced by ink type, sterility claims, or manufacturing sources. Bacillus species were the most commonly identified, followed by Pseudomonas, Staphylococcus, and Lysinibacillus.

Surprisingly, around one-third of inks marketed as "sterile" were found to contain microorganisms. Some isolates, such as P. putida and Alcaligenes faecalis, are known opportunistic pathogens with ties to human infections. Network modeling indicated a scale-free structure connecting inks, pathogens, and potential disease outcomes, while pan-species analysis suggested an "open" microbial community, implying the potential for further unidentified contaminants.

These results emphasize the widespread and diverse nature of microbial contamination in tattoo and PMU inks, highlighting the necessity for advanced detection techniques, enhanced surveillance, and standardized manufacturing practices to ensure product safety. The study acknowledges the contributions of Drs. Kidon Sung and Miseon Park and is funded by the U.S. Food and Drug Administration's Division of Microbiology, National Center for Toxicological Research.