Is there significant difference in the activity of strong carbol fuchsin against bacteria and fungi?

Abstract

Dear Editor, The pathogenic bacteria and fungi developed resistance to multiple antibiotics, making them difficult to treat with standard therapies. Hence, using alternative strategies such as strong carbol fuchsin (SCF) dye to treat them is urgent.[1] SCF is a red-colored dye commonly used in histology to stain biological tissues and microorganisms. SCF has a high affinity for acidic structures such as nucleic acids and polysaccharides, making it useful for staining cell nuclei and cartilage. It is also used in Gram staining to differentiate bacteria based on their cell wall composition. Gram-positive bacteria retain the stain, while Gram-negative bacteria do not.[2] Candida albicans were isolated from three sites (vagina, oral, and urine) in 30 patients and cultured in Sabouraud dextrose agar and confirmed by germ tube test. A total of 30 Staphylococcus aureus and Pseudomonas aeruginosa were isolated from wounds by culturing the specimens in three media (Blood Agar, MacConkey’s agar, and Mannitol Salt agar). The well diffusion method is used to evaluate the activity of SCF; the diameter of the inhibited growth is measured in millimeters. It is considered sensitive when the inhibition zone is >13 mm. All the statistical analysis was performed using SPSS 26 software (SPSS Inc., Chicago, USA). All 30 isolates of C. albicans showed 100% sensitivity to SCF, while 96.7% of bacterial isolates were sensitive to SCF [Figure 1]. The mean of the inhibition zone for C. albicans was 19.17 ± 2.37 mm, whereas for bacteria was 22.37 ± 5.63 mm with significant differences (P = 0.006) [Table 1]. That means bacteria are more susceptible to SCF than yeast with large inhibition zone.Figure 1: Antimicrobial activity of strong carbol fuchsinTable 1: The mean of inhibition zone of strong carbol fuchsin for bacteria and yeastAnother study found 100% efficacy of safranin against Gram-positive bacteria (S. aureus) but only 20% sensitivity against Gram-negative bacteria (P. aeruginosa).[3] Only a few researchers have looked at SCF’s antibacterial activity against microorganisms. On Fusobacterium nucleatum and Porphyromonas gingivalis, photodynamic therapy with Safranine O had a pronounced antibacterial effect. Streptococcus gordonii, on the other hand, was fully eradicated.[4] Another study, however, found that certain strains of bacteria could develop resistance to safranin over time when exposed to the dye in laboratory cultures.[5] The percentage of resistance and sensitivity of organisms differ depending on a number of factors, including the concentration of the dye, the strain of the pathogen being tested, and the conditions under which the microorganism are grown and tested.[6] CONCLUSION The bacteria (S. aureus and P. aeruginosa) 22.37 ± 5.63 mm are more susceptible to SCF than C. albicans 19.17 ± 2.37 mm significantly (P = 0.006). Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.