Safety Considerations for Lyophilized Human Amniotic Membrane Impregnated with Colistin and Silver Nanoparticles.

Lyophilized human amniotic membrane (HAM) and silver nanoparticles (AgNPs) have multispectral applications as a biological dressing. The present study focuses on the safety aspects of HAM coated with colistin and AgNPs (HACoN) dressing in relation to its structural and hematological changes. Four dressing groups were designed for the study, HAM, HAM coated with colistin (HACo), HAM coated with AgNPs (HAN), and HAM coated with colistin (HACo) and HACoN. Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were utilized for constitutional analysis. Biological safety was checked by applying HAM of all groups on open excisional burn wounds on Sprague-Dawley rats for 21 days. The skin, kidneys, liver, and spleen were removed, and histological analysis was performed for detailed structural analysis. Oxidative stress was assessed using homogenate from newly generated skin. No structural or biochemical change was observed in any of the study groups as observed by SEM and FTIR. After 21 days of grafting, wounds were healed properly with normal skin, and no anomaly was observed in related to kidneys, spleen, and liver. Some of antioxidant enzymes were increased, while malondialdehyde which is a reactive oxygen species was reduced in the skin tissue homogenate of HACoN group. Impregnation of colistin and AgNPs in combination on HAM has no effects on hematological and structural constitution of HAM. It leaves no obvious change in vital organs of rats and improves oxidative stress and inflammation. Hence, it can be claimed that HACoN is a biologically safe antibacterial dressing.

Synergistic efficacy of colistin and silver nanoparticles impregnated human amniotic membrane in a burn wound infected rat model.

Antimicrobials used to treat burn wound infections have become multidrug-resistant, thus delaying wound healing. When combined with silver nanoparticles, antibiotics create a multifaceted antibacterial mechanism of action to which bacteria are incapable of developing resistance. Similarly, the amniotic membrane has been found to lower the bacterial number. The purpose of the current study was to observe the antibacterial activity of combined topical colistin with silver nanoparticles and decellularized human amniotic membrane as a dressing in burn wounds infected with bacteria with the goal of promoting faster healing. Bacteria commonly isolated from burn wounds and the most sensitive topical antibiotic were identified. Colistin, silver nanoparticles and combined colistin with silver nanoparticles were impregnated into decellularized human amniotic membranes. These wound dressings were evaluated in third-degree multidrug-resistant bacterial infected thermal burns induced in rats. Out of a total of 708 pus samples from burn wounds, Pseudomonas aeruginosa was the most prevalent pathogen 308 (43.5%), followed by Klebsiella pneumoniae 300 (42.4%). Topical colistin was 100% sensitive for both bacteria. Overall, maximum wound contraction (p < 0.05), and increased collagen deposition (+++) with no isolation of bacteria from wound swabs were noted on day 21 for the combined colistin with silver nanoparticle-loaded human amniotic membrane dressing group. Our study concluded that the increased antimicrobial activity of the novel combination of colistin and silver nanoparticle-loaded decellularized human amniotic membrane manifested its potential as an effective burn wound dressing.

Comparison of serum levels of Cystatin-C and traditional renal biomarkers for the early detection of pre-hypertensive nephropathy.

OBJECTIVE: To compare serum Cystatin-C and serum creatinine levels along with estimated glomerular filtration rate of apparently healthy people of South Asian descent with pre-hypertension to determine which is better in detecting reversible renal dysfunction. METHODS: :The comparative cross-sectional study was conducted at the Army Medical College, Rawalpindi, Pakistan, in 2013-14, and comprised apparently normal healthy male and female volunteers. The subjects were divided into normotensive group 1 and pre-hypertensive group 2. Serum Cystatin-C levels were measured by sandwhich enzyme-linked immunosorbent assay technique whereas serum creatinine levels were measured by Jaffe's procedure. Glomerular filtration rate estimation was done by using standard equations. SPSS 20 was used for data analysis. RESULTS: Of the 78 subjects, 39(50%) were in normotensive group 1 and 39(50%) in the pre-hypertensive group 2. The mean age was 38.74 } 5.71 years in group 1 and 38.07 } 3.84 years in group 2. Serum Cystatin-C levels were higher in group 2 than in group 1(p= 0.0001), whereas serum creatinine levels manifested no statistical difference between the groups (p=0.106). Estimated glomerular filtration rate based on Cystatin-C significantly decreased in group 2 than in group 1 (p=0.0001). Serum Cystatin-C displayed a significant positive correlation and estimated glomerular filtration rate based on Cystatin-C negative correlation with the rising blood pressure values (p=0.0001).Serum Cystatin-C reflected a very high sensitivity and specificity at a cutoff value of 0.77 mg/l compared to serum creatinine. CONCLUSIONS: Serum Cystatin-C and Estimated glomerular filtration based on rate Cystatin-C appeared to be better renal biomarkers in the detection of pre-hypertensive nephropathy.

Comparative In Vitro Efficacy of Doripenem and Imipenem Against Multi-Drug Resistant Pseudomonas aeruginosa.

OBJECTIVE: To compare the in vitro efficacy of doripenem and imipenem against multi-drug resistant (MDR) Pseudomonas aeruginosa from various clinical specimens. STUDY DESIGN: Descriptive cross-sectional study. PLACE AND DURATION OF STUDY: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi, from November 2012 to November 2013. METHODOLOGY: MDR Pseudomonas aeruginosa isolates from various clinical samples were included in the study. Susceptibility of Pseudomonas aeruginosa against doripenem and imipenem was performed by E-test strip and agar dilution methods. The results were interpreted as recommended by Clinical Laboratory Standard Institute (CLSI) guidelines. RESULTS: The maximum number of Pseudomonas aeruginosa were isolated from pure pus and pus swabs. In vitro efficacy of doripenem was found to be more effective as compared to imipenem against MDR Pseudomonas aeruginosa with both E-test strip and agar dilution methods. Overall, p-values of 0.014 and 0.037 were observed when susceptibility patterns of doripenem and imipenem were evaluated with E-test strip and agar dilution methods. CONCLUSION: In vitro efficacy of doripenem was found to be better against MDR Pseudomonas aeruginosaas compared to imipenem when tested by both E-test and agar dilution methods.