Retrospective analysis of microbial contamination in tattoo and permanent makeup inks

Abstract Microbial contamination of tattoo and permanent makeup (PMU) inks presents a persistent public health risk because these products are injected directly into the dermis. Despite regulatory oversight, outbreaks of ink-related infections continue to be reported. This study retrospectively analyzed 259 unopened tattoo and PMU ink products collected over the past decade in the United States to evaluate contamination prevalence, microbial diversity, and potential health risks. The pooled prevalence of bacterial contamination among tattoo and PMU ink samples across the four surveys was 35.4% (95% CI: 21.6–49.1%), with similar contamination rates for tattoo and PMU inks (~ 33%). Contamination status was not significantly associated with ink type, sterility claim, or manufacturing origin. Bacillus species were most frequently isolated, followed by Pseudomonas , Staphylococcus , and Lysinibacillus . Importantly, nearly one-third of inks labeled as “sterile” contained microorganisms. Several isolates, including P. putida and Alcaligenes faecalis , are opportunistic pathogens with documented links to human infections. Network modeling revealed a scale-free structure connecting inks, pathogens, and potential disease outcomes, while pan-species analysis indicated an “open” microbial community, suggesting that additional contaminants are likely to be identified with further sampling. These findings underscore that microbial contamination in tattoo and PMU inks is widespread and diverse, reinforcing the need for sensitive molecular detection methods, expanded surveillance, and harmonized manufacturing standards to ensure product safety.