ABSTRACT
The human amniotic membrane is the inner most layer of placenta and has antimicrobial effect, due to the presence of human beta-defensins and elafins. The purpose of this study is to investigate the effect of dilution reduction of 0.5 McFarland prepared from standard bacterial strains of Salmonella enterica BAA-708, Escherichia coli ATCC25922, Pseudomonas aeruginosa ATCC27853, Klebsiella pneumoniae ATCC7881, and Enterococcus faecalis ATCC29212 on antibacterial effect of human amniotic membranes in vitro. Amniotic membranes were obtained from the bank of organ transplantation in Imam Khomeini hospital, of women with elective cesarean section whose HIV, HBV, HCV and VDRL serological tests were negative. They were cut to 1.5x1.5 cm pieces. Then 0.5 McFarland suspensions of 1.5x10[8], 0.5x10[7] and 1.5x10[6] dilutions were prepared from bacteria which then were spread on Mueller Hinton medium agar and a piece of membrane was put in the center of each plate. After 24 hours incubation at 37[degree]C, the results were observed. In 0.5 McFarland standard dilution an inhibition zone was created in three standard strains of Pseudomonas aeruginosa, Escherichia coli, and Salmonella enterica unlike the other two strains. There was no change in the above results with two other dilutions and inhibition zone of sensitive strains was not created. Dilution reduction of microbial strains does not affect the antibacterial impact of amniotic membrane and dilution reduction does not yield to a false positive response and the conversion of resistant to sensitive strains
ABSTRACT
Human amniotic membrane [HAM] forms the inner wall of the membranous sac that surrounds and protects the embryo during gestation. The main advantages of amniotic membrane transplantation [AMT] in the treatment of bacterial keratitis are its epithelial bandage properties. Previous studies have documented the presence of some antimicrobial proteins and peptides in amniotic fluid such as lactoferrin, lysozyme, bactericidal or permeability increasing protein, calprotectin [MRP8/14 protein complex], LL37, and neutrophil defensins [Human Neutrophil Peptides, HNP 1-3]. Furthermore, the amniotic membrane does not express HLA-A, B, C or DR surface antigens, which may help avoid rejection after its transplantation. Thus, it can be used as a biological immune barrier. The purpose of this study was to evaluate the effectiveness of the amniotic membrane's healing properties in rabbits with pseudomonas keratitis. By using an animal model, 14 rabbits were divided into two groups of controls and cases. A syringe was used to inoculate the corneal stroma of the animals by Pseudomonas aeruginosa ATCC27853. After 20 hours pseudomonas keratitis was created and amniotic membrane was transplanted to the cornea of the case group. The infiltration size were observed on the first, third and seventh days after the experiment. Corneal perforation was seen in the controls [P<0.001] but amniotic membrane prevented perforation in the case group [P=0.02]. Transplantation of amniotic membrane in the primary stages of pseudomonas keratitis treatment remarkably prevents corneal perforation and it can be used to control the disease process