Evaluation of the Combined Antibacterial Effect of Ciprofloxacin and Staphyloxanthin from Staphylococcus aureus Against Pathogenic Bacteria.

Abstract

Staphyloxanthin is golden yellow-orange carotenoid pigment produced by most Staphylococcus aureus bacteria, which plays an important role in virulence factors protecting bacteria from ROS produced by immune system. The aim of this study was to evaluate antibacterial activity of Staphyloxanthin and its combination with Ciprofloxacin antibiotic against some pathogenic bacteria. Twenty-five S.aureus isolates were obtained from various clinical sources in Baghdad hospital and identified. Antibiotics susceptibility tests revealed the highest resistance to (Penicillin G 100%, cefoxitin and oxacillin 96%), while lowest resistance to Amikacin and gentamicin, Clindamycin 20%,16% ,12% respectively,

Staphyloxanthin pigment production was detected on skim milk agar, 84% of the isolates were producers and the quantitative estimation using Spectrophotometer at O.D450nm revealed S4 isolate was highest production (Means O.D ±S.D=1.248).Staphyloxanthin pigment was extracted  using methanol and purified by Column chromatography.

Antibacterial activity of purified staphyloxanthin was evaluated by agar well diffusion method against  (P. aeruginosa, S. aureus, K. pneumoniae, E. cloacae, E. coli, E. faecalis) at different concentrations

 )100- 12.5 ug/ml(.The maximum inhibition zones were observed against E. cloacae (22±1mm), followed by K. pneumoniae (20.5±0.5mm) and then E. faecalis (16.5±2.1mm),while weak activity was observed against E.coli (10±1),statistically analysis showed significant differences (p ≤ 0.05), and no activity was recorded against (P. aeruginosa, S. aureus).

Combination effect of Staphyloxanthin with Ciprofloxacin showed high Antibacterial efficacy as indicated by the increase in diameter of inhibition zone compared to ciprofloxacin alone as bacterial follows K.pneumoniae, E.clocaea, E.faecalis (p ≤ 0.05), while no enhancement was observed in E. coli.