The harm of pathogenic bacteria to humans has promoted extensive research on physiological processes of pathogens, such as the mechanism of bacterial infection, antibiotic mode of action, and bacterial antimicrobial resistance. Most of these processes can be better investigated by timely tracking of fluorophore-derived antibiotics in living cells. In this paper, we will review the recent development of fluorescent antibiotics featuring the conjugation with various fluorophores, and focus on their applica-tions in fluorescent imaging and real-time detection for various physiological processes of bacteria in vivo.

Objective:To study the utility of immunohistochemistry (IHC) in differential diagnosis between trichoblastoma (TB) and basal cell carcinoma (BCC).Methods:Fifty-eight cases of TB and 40 cases of BCC were collected at Fudan University Shanghai Cancer Center from January 2009 to December 2019 and retrospectively analyzed by IHC for bcl-2, Ber-EP4, CD10, CK20 and Ki-67. Fisher exact test was performed for statistical analysis.Results:Twenty-five (43.1%) TBs and 5 (12.5%) BCCs showed bcl-2 staining in the outermost layer of the epithelial nests, the difference was statistically significant ( P<0.01). The proportion of cases with bcl-2 staining>75% of epithelial cells in BCC group was much higher than that in TB group (40% vs. 12.1%; P<0.01). BCC group showed larger proportions with Ber-EP4 staining>75%, 51%-75% of epithelial cells than TB group (12.5% vs. 1.7%, 37.5% vs. 8.6%; P<0.05). Fifty-five (94.8%) TBs demonstrated CD10 expression in the follicular stroma, while only 16 (40.0%) BCCs showed focal or scattered CD10 expression in reactive fibrous stroma ( P<0.01). CK20 expression was present in 37 (63.8%) TBs with scattered pattern, but BCCs exhibited no CK20 staining except for only one case (2.5%) showing focal staining ( P<0.01). Compared with TB group, the BCC group included more cases with Ki-67 labeling index ≥15% on average and ≥25% in hotspot areas ( P<0.05). Conclusion:IHC is helpful in differential diagnosis between TB and BCC. Scattered CK20 staining pattern and stromal CD10 expression support the diagnosis of TB. Bcl-2 staining limited to the outermost layer of the proliferation is more likely to be found in TB. In contrast, Ber-EP4 positivity and higher Ki-67 labeling index tend to be present in BCC.