The activity of some dyes against clinically isolated bacteria

Document Type : Original Article


Al-Furat Al-Awsat Technical University, Babylon Technical institute, Iraq


Background: The increasing resistance of many bacterial pathogens against antibiotic demanded urgent new or repurposing therapeutic strategies such as utilizing certain dyes that may be a promising branch in microbial therapy. Material and methods: Two types of bacteria, Escherichia coli (E. coli) were isolated from the urine sample and Staphylococcus aureus (S. aureus) from the wounds using cotton swabs. The well diffusion method was used after overnight incubation for antibiotic sensitivity testing. The diameter of inhibited growth was measured per millimeter for three antibiotics (amoxicillin, gentamicin, ceftriaxone) that were added to one dish, and dyes (leishman stain1, leishman stain 2, India ink, crystal violet, safranin) that were added to the other dish. Results: Crystal violet was 100% active against E. coli and 50% active against S. aureus. Safranin was 25% active against E. coli while it showed higher activity against S. aureus 75%. India ink and Leishman stain 2 were inactive against S. aureus whereas they revealed 50% and 25% activity against E. coli respectively. Leishman stain 1 was 25% active against E. coli and 50 % active against S. aureus. The mean of inhibition zone of amoxicillin in E. coli 40.75± 11.95 mm that was higher than S. aureus 35.50±6.40 mm without significant differences (P= 0.46). The other antibiotics, gentamicin and ceftriaxone, also showed no significant differences (P= 0.29 and P= 0.85) respectively. The mean of inhibition zone of Crystal violet in E. coli 20.25± 0.5 mm that was higher than S. aureus 17.25± 13.88 without significant differences (P= 0.68). Conclusion: All investigated dyes (leishman1, leishman2, India ink, crystal violet, safranin) showed antibacterial activity in different percentages. Crystal violet was 100% sensitive to E. coli and 50% sensitive to S. aureus.


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