Antimicrobial effects of craniopharyngioma cystic fluid

Abstract

Background Tumours are known to increase the risk of infections, especially those occurring in the central nervous system where insertion of surgical hardware/shunts such as in craniopharyngiomas may be required. However, infections are surprisingly scarce in craniopharyngioma cases. In this study, we explored the possibility of antimicrobial effects of craniopharyngioma cystic fluid. Methods The antibacterial effect of craniopharyngioma cystic fluid samples against selected human pathogens: Escherichia. coli, S. aureus and S. pneumoniae were determined using the agar disc diffusion method. Streptomycin and ampicillin were used as controls. The test organisms were cultured in Mueller-Hinton broth overnight at 37 °C. McFarland standard was used as a reference to adjust the inoculum size of each test organism to a concentration of 1 × 10⁶ CFU/ml using sterile broth. Results The craniopharyngioma cystic fluid inhibited growth of Gram-positive bacteria S. aureus and S. pneumoniae, but not the Gram-negative bacteria, E. coli. The samples showed the highest zones of S. pneumoniae growth inhibition of up to 20.0 ± 1.0 mm compared with 18.0 ± 1.0 mm of streptomycin and 9.0 ± 0.0 mm of ampicillin. Conclusion Craniopharyngioma cystic fluid showed significant antibacterial properties against Gram-positive bacteria. This novel finding has implications in the way we view infections in craniopharyngioma patients. More studies need to be carried out to further elucidate this unique finding and possibly exploit these antimicrobial properties.