The antimicrobial susceptibility patterns of diabetic foot ulcers in the South African public healthcare sector.

BACKGROUND: Diabetic foot syndrome is defined as the presence of a diabetic foot ulcer (DFU) associated with neuropathy, peripheral artery disease and infection. While the use of antimicrobials in the treatment of DFU infection remains a mainstay, the choice of antimicrobial remains problematic owing to the presence of multidrug-resistant polymicrobial infections. In the South African public healthcare sector, the treatment of DFUs is based on the Standard Treatment Guidelines (STGs) and the Essential Drug List. These guidelines are developed using evidence-based medicine and are based on global susceptibility patterns rather than local susceptibility data, and may not provide the most appropriate treatment options. OBJECTIVES: To determine the antimicrobial susceptibility patterns of DFUs isolated from patients visiting selected Gauteng provincial public hospitals in order to determine a clinically effective treatment protocol for the management of these infections. METHODS: Sample swabs were taken from 51 DFUs using the Levine method. Each sample swab was spread onto blood agar plates, and thereafter individual pathogens were isolated. The antimicrobial susceptibility patterns of all isolated pathogens were determined using zone of inhibition measurements. Pathogens were grouped according to macromorphological characteristics as well as susceptibility patterns, and a representative isolate from each group was then identified. RESULTS: A total of 51 DFU ulcer swabs from 45 patients were included in the study. From the sample swabs, a total of 445 pathogens were isolated. The most effective antimicrobial was found to be gentamicin, followed by ciprofloxacin. Amoxicillin/clavulanic acid, the first-line treatment according to the STGs, was found to be ineffective for many of the isolated pathogens. The most commonly isolated pathogens were Proteus mirabilis, Enterococcus faecalis and Pseudomonas aeruginosa. CONCLUSION: These findings demonstrate the urgent need to reassess the STGs and base treatment plans on local epidemiological data. This study provides valuable data on common causative pathogens in DFU infections, as well as the resistance patterns of these pathogens, forming a baseline on which to base future DFU treatment plans.

Substrate temperature dependence of structure and optical properties of ZnTiO3:Er3+/Yb3+ thin films synthesized by pulsed laser deposition.

ZnTiO3:Er3+,Yb3+ thin film phosphors were successfully deposited by pulsed laser deposition (PLD) at different substrate temperatures. The distribution of the ions in the films was investigated and the chemical analysis showed that the doping ions were homogeneously distributed in the thin films. The optical response of the phosphors revealed that the reflectance percentages of the ZnTiO3:Er3+,Yb3+ vary with the silicon substrate temperature due to the differences in the thickness and morphological roughness of the thin films. Under 980 nm diode laser excitation, the ZnTiO3:Er3+,Yb3+ film phosphors displayed up-conversion emission from the Er3+ electronic transitions, with violet, blue, green, and red emission lines at 410, 480, 525, 545 and 660 nm from 2H9/2 â†’ 4I15/2, 4F7/2 â†’ 4I15/2, 2H11/2 â†’ 4I15/2, 4S3/2 â†’ 4I15/2 and 4F9/2 â†’ 4I15/2 transitions, respectively. The up-conversion emission was enhanced by increasing the silico (Si) substrate temperature during the deposition. Based on the photoluminescence properties and decay lifetime analysis, the energy level diagram was established and the up-conversion energy-transfer mechanism was discussed in detail.