PURPOSE: This work aimed to develop and characterize chitosan (CS)-polyvinyl alcohol (PVA) blended electrospun multifunctional nanofiber loaded with curcumin (CUR) and zinc oxide (ZnO) to accelerate diabetic wound healing in STZ-induced diabetic rats.
RESULTS: In-vitro characterization results revealed that nanofiber was fabricated successfully using the electrospinning technique. SEM results confirmed the smooth surface with web-like fiber nanostructure diameter ranging from 200 - 250 nm. An in-vitro release study confirmed the sustained release of CUR and ZnO for a prolonged time. In-vitro cell-line studies demonstrated significantly low cytotoxicity of nanofiber in HaCaT cells. Anti-bacterial studies demonstrated good anti-bacterial and anti-biofilm activities of nanofiber. In-vivo animal studies demonstrated an excellent wound-healing efficiency of the nanofibers in STZ-induced diabetic rats. Furthermore, the ELISA assay revealed that the optimized nanofiber membrane terminated the inflammatory phases successfully by downregulating the pro-inflammatory cytokines (TNF-α, MMP-2, and MMP-9) in wound healing. In-vitro and in-vivo studies conclude that the developed nanofiber loaded with bioactive material can promote diabetic wound healing efficiently via multifunction action such as the sustained release of bioactive molecules for a prolonged time of duration, proving anti-bacterial/anti-biofilm properties and acceleration of cell migration and proliferation process during the wound healing.
DISCUSSION: CUR-ZnO electrospun nanofibers could be a promising drug delivery platform with the potential to be scaled up to treat diabetic foot ulcers effectively.
METHODS: A retrospective analytical cross-sectional study was conducted over 2 years. The cumulative antibiograms were constructed in accordance with current guidelines.
RESULTS: A total of 976 first isolate cultures were obtained from ICUs of the different referral hospitals. K. pneumoniae (8.8%, 8.1%) was a predominant pathogen in Windhoek Central hospital ICU in 2017 and 2018. In Oshakati intermediate hospital ICU, Enterobacter sp. (22.2%) and P. aeruginosa (37.5%) were the common pathogens in 2017 and 2018, respectively. A. baumannii isolates were >90% susceptibility to colistin, carbapenems, and tigecycline in 2017. In 2017, K. pneumoniae isolates were more susceptible to carbapenems (94% and 93.8% among isolates), amikacin (89.3%), and tigecycline (88.7%). In 2018, K. pneumoniae isolates were 100% susceptible amikacin, colistin, and carbapenems. S. maltophilia isolates were more than 80% susceptible to all the tested antibiotics. S. aureus isolates were 100% susceptible to linezolid, rifampicin, teicoplanin, and vancomycin in 2017 and in 2018. Its susceptibility to these antibiotics did not change.
CONCLUSION: The susceptibility patterns of the common isolated gram-negative pathogens were highly variable. Meropenem in combination with gentamicin is now the recommended antibiotic combination for empiric therapy for patients with LRTIs in Windhoek Central Hospital ICU.