Antimicrobial activities of endophytic fungi residing in Aloe vera against diabetic wound pathogens

Aims@#Endophytic fungi are organisms that colonize living plant tissues without causing significant symptoms of diseases. They are known as the repository of bioactive compounds. This study was aimed to isolate endophytic fungi associated with Aloe vera and to assess their antimicrobial activity against the diabetic wound pathogens that result to lower limb amputations. @*Methodology and results@#In this study, 84 endophytic fungi were isolated from A. vera by using 5% sodium hypochlorite and 70% ethanol as surface sterilants. On preliminary antimicrobial screening by agar plug assay, 12 (14.3%) isolates showed significant antagonistic activity on the test microorganisms. Two of the endophytes were identified as Aspergillus flavus and Colletotrichum gloeosporioides through morphological and molecular techniques. The fungal cultures fermented in shake flask were extracted subsequently with hexane, dichloromethane, ethyl acetate, and n-butanol. Ethyl acetate and dichloromethane extracts of A. flavus and C. gloeosporioides inhibited all test bacteria. The compounds in the extracts were seemed to be semi-polar in nature. On broth microdilution assay, minimal inhibitory and minimal lethality concentration of ethyl acetate extracts of the fungi were found in the range of 0.63−2.50 and 1.25−5.00 mg/mL, respectively. @*Conclusion, significance and impact of study@#This study reveals that A. vera harbours a wide diversity of endophytic fungi. A. flavus and C. gloeosporioides showing broad spectrum antimicrobial activity on wound pathogens may be potential sources of bioactive compounds. Further investigations should be conducted to isolate and identify the antimicrobial compound produced by these fungal isolates.

Antimicrobial Efficacy of Penicillium amestolkiae elv609 Extract Treated Cotton Fabric for Diabetic Wound Care

Diabetes mellitus is a chronic disorder which affects millions of population worldwide. Global estimates published in 2010 reported the world diabetic prevalence as 6.4%, affecting 285 million adults. Foot ulceration and wound infection are major forms of disabilities arising from diabetic diseases. This study was aimed to develop a natural antimicrobial finishing on medical grade textile that meets American Association of Textiles Chemists and Colorists (AATCC) standard. The textile samples were finished with the ethanolic extract of Penicillium amestolkiae elv609, an endophytic fungus isolated from Orthosiphon stamineus Benth (common name: cat's whiskers). Endophyte is defined as microorganism that reside in the living plant tissue, without causing apparent disease symptom to the host. The antimicrobial efficacy of the ethanolic extract of P. minioluteum was tested on clinical pathogens isolated from diabetic wound. The extract exhibited significant inhibitory activity against 4 bacteria and 1 yeast with the minimal inhibitory concentration ranged from 6.25 to 12.5 mg/mL. The results indicate different susceptibility levels of the test microorganism to the ethanolic extract. However, the killing activity of the extract was concentration-dependent. The finished medical textile showed excellent antimicrobial efficacy on AATCC test assays. All the microbial cultures treated with the textile sample displayed a growth reduction of 99.9% on Hoheinstein Challenge Test. The wash durability of the finished textile was found good even after 50 washes with commercial detergent. Besides, the gas chromatography mass spectrometry analysis showed that 6-octadecenoic acid and diethyl phthalate were the main bioactive constituents of the extract. In conclusion, the developed medical textile showed good antimicrobial efficacy on laboratory tests. This work can be extended to in vivo trials for developing healthcare textile products for antimicrobial applications.