Makeup testers as reservoirs and transmission sources of antibiotic resistant bacteria.

Background: Recently, the cosmetic market has been attracting growing attention. However, studies on the bacterial safety of these products are still very rare. In this preliminary study, we aimed to detect the presence of antibiotic-resistant staphylococci isolates from makeup testers beauty retailers in the city of Batna, Algeria.

Methods: In May 2019, a total of 325 samples were collected by swabbing the surface of different types of makeup testers including mascara, lipstick, eye shadow, face powder and blusher in different beauty retailers. The samples were immediately subjected to non-selective culture, followed by selective isolation. Representative colonies were identified using matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). Antimicrobial susceptibility testing was carried out by agar disk diffusion method.

Results: Nineteen isolates were obtained from the different types of makeup testers and were identified as: Bacillus mojavensis (n = 1), Staphylococcus haemolyticus (n = 4), Bacillus subtilis (n = 3), Bacillus cereus (n = 3), Bacillus pumilus (n = 1), Bacillus sp. (n = 1), Bacillus amyloliquefaciens (n = 1), Staphylococcus warneri (n = 1) and four unidentified species (n = 4). Antimicrobial susceptibility test results revealed that Staphylococcus haemolyticus presented the highest antibiotic resistance level.

Conclusions: These results showed that makeup testers may act as reservoir and pathway of antibiotic-resistant Gram-positive bacteria transmission. Hence, to reduce health risks and enhance public safety awareness, it is crucial to implement effective control measures and preventive strategies.