Isolation, identification, and virulence and drug resistance examination of Pluralibacter gergoviae from a batch of facial masks with microorganisms out of limits

Abstract:

[Background] In recent years, cosmetic recall cases caused by contamination with objectionable microorganisms have kept emerging. The microbial detection indicators in the Cosmetic Safety Technical Specifications (2015 Edition) are not perfect and difficult to meet the needs of quality control and evaluation of cosmetics products. [Objective] To isolate and identify the contaminant microorganisms in a batch of facial masks with microorganisms out of limits in the national sampling inspection of cosmetics in 2022, explore the performance of different identification methods, determine whether the contaminant microorganisms are objectionable microorganisms or not, and evaluate the safety of the contaminant microorganisms.[Methods] According to the Cosmetic Safety Technical Specifications (2015 Edition), the contaminant microorganisms in the facial masks were isolated and identified by VITEK 2 system, matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), and 16S rRNA gene sequencing. Furthermore, the safety evaluation and detection of virulence genes and drug resistance genes were carried out for the contaminant microorganisms. [Results] The results obtained with the three identification techniques all showed that the contaminant microorganism in the facial masks was an objectionable microorganism, Pluralibacter gergoviae. High-throughput sequencing detected 52 virulence genes and predicted 429 other virulence-related genes, which suggested that this bacterium had great safety risks. At the same time, 24 drug resistance genes were detected, suggesting that the bacterium may be resistant to 24 antibiotics such as penicillin, cephalosporin, vancomycin, tetracycline, and aminoglycosides. Moreover, 10 multi-drug resistance genes were detected, and the resistance mechanism was associated with the production of efflux pumps. It is suggested that the bacterium have a certain risk of multi-drug resistance. [Conclusion] In this study, an objectionable microorganism P. gergoviae was isolated from a batch of facial masks with microorganisms out of limit. This bacterium is capable of producing toxins and has a potential safety risk of multidrug resistance. It should be considered to include this bacterium into the microbial detection after risk assessment.