Background: Aminoglycosides are a group of antibiotics that have been widely used in the treatment of life-threatening infections of Gram-negative bacteria. Objectives: This study aimed to evaluate the frequency of aminoglycoside resistance genes in Enterococcus and Salmonella strains isolated from clinical samples by PCR. Materials and Methods: In this study, 140 and 79 isolates of Enterococcus and Salmonella were collected, respectively. After phenotypic biochemical confirmation, 117 and 77 isolates were identified as Enterococcus and Salmonella, respectively. After the biochemical identification of the isolates, antibiotic susceptibility for screening of resistance was done using the Kirby-Bauer method for gentamicin, amikacin, kanamycin, tobramycin and netilmycin. DNA was extracted from resistant strains and the presence of acc (3)-Ia, aac (3′)-Ib, acc (6)-IIa ,16SrRNA methylase genes (armA and rat) was detected by PCR amplification using special primers and positive controls. Results: Enterococcus isolates have the highest prevalence of resistance to both kanamycin and amikacin (68.4%), and Salmonella isolates have the highest prevalence of resistance against kanamycin (6.9%). Ninety-three and 26 isolates of Enterococcus and Salmonella at least were resistant against one of the aminoglycosides, respectively. Moreover, 72.04%, 66.7%, and 36.6% of the resistant strains of Enterococcus had the aac (3′)-Ia, aac (3′)-IIa, and acc (6′)-Ib genes, respectively. None of the Salmonella isolates have the studied aminoglycoside genes. Conclusions: Our results indicate that acetylation genes have an important role in aminoglycoside resistance of the Enterococcus isolates from clinical samples. Moreover, Salmonella strains indicate very low level of aminoglycoside resistance, and aminoglycoside resistance genes were not found in Salmonella isolates. These results indicate that other resistance mechanisms, including efflux pumps have an important role in aminoglycoside resistance of Salmonella.

Background:Aminoglycosides are a group of antibiotics that have been widely used in the treatment of life-threatening infections of Gram-negative bacteria.Objectives:This study aimed to evaluate the frequency of aminoglycoside resistance genes in Enterococcus and Salmonella strains isolated from clinical samples by PCR.Materials and Methods:In this study, 140 and 79 isolates of Enterococcus and Salmonella were collected, respectively. After phenotypic biochemical confirmation, 117 and 77 isolates were identified as Enterococcus and Salmonella, respectively. After the biochemical identification of the isolates, antibiotic susceptibility for screening of resistance was done using the Kirby-Bauer method for gentamicin, amikacin, kanamycin, tobramycin and netilmycin. DNA was extracted from resistant strains and the presence of acc (3)-Ia, aac (3′)-Ib, acc (6)-IIa ,16SrRNA methylase genes (armA and rat) was detected by PCR amplification using special primers and positive controls.Results:Enterococcus isolates have the highest prevalence of resistance to both kanamycin and amikacin (68.4%), and Salmonella isolates have the highest prevalence of resistance against kanamycin (6.9%). Ninety-three and 26 isolates of Enterococcus and Salmonella at least were resistant against one of the aminoglycosides, respectively. Moreover, 72.04%, 66.7%, and 36.6% of the resistant strains of Enterococcus had the aac (3′)-Ia, aac (3′)-IIa, and acc (6′)-Ib genes, respectively. None of the Salmonella isolates have the studied aminoglycoside genes.Conclusions:Our results indicate that acetylation genes have an important role in aminoglycoside resistance of the Enterococcus isolates from clinical samples. Moreover, Salmonella strains indicate very low level of aminoglycoside resistance, and aminoglycoside resistance genes were not found in Salmonella isolates. These results indicate that other resistance mechanisms, including efflux pumps have an important role in aminoglycoside resistance of Salmonella.

10.30699/jambs.30.139.154Background & Objective: Phage therapy could be used as an alternative method to antibiotic treatments. The purpose of this study was to evaluate the antibacterial activities of isolated lytic bacteriophage against ciprofloxacin-resistant strain of Salmonella infanits in vitro conditions. Materials & Methods:The standard strain of Salmonella infantis and its specific bacteriophage was isolated by soft agar method. Phage susceptibility to heat and pH was evaluated by the Double-Layer Agar method. In vitro assay was carried out on human epithelial type 2 (HEp-2) cells to investigate the effect of bacteriophage on the cytotoxic and invasion of Salmonella infantis to human epithelial cells.Results: Head and tail morphology of bacteriophages against Salmonella infantis were identified by transmission electron microscopy and assigned to the Myoviridae family. The results of the double-layer agar assay showed that the titer of bacteriophages was 1.8×10 7 PFU/ml. bacteriophage was stable at 4 ֯ C and the best quantification of bacteriophage was determined at pH=8. The isolated bacteriophage was specific for Salmonella infantis and had no lytic activity against other pathogenic bacteria. In the evaluation of the binding and invasion of Salmonella infantis to the HEp-2 cell line, as expected, the lytic activity of specific bacteriophage was observed following inoculation. Conclusion:Additional studies are needed for better understanding of the interaction between phage, microorganisms and human host before applying phage therapy on a large scale.

Mercaptopurine with the scientific name of 1.7-dihydro-6H-purine-6-thione and brand name of Purinethol, is among cancer treatment drugs. Accordingly, it is used to prevent the formation and expansion of cancer cells, the high solubility of which is effective on their better performance. In this study, using the calculations of Density functional theory (DFT) at level PW91/6-31(d), the stability of the drug structure in green and aqueous solvents was investigated, and by performing both NBO (Natural band orbital) and NMR (Nuclear magnetic resonance) calculations, the amount of molecular stability was calculated and no decay of the structure was found. Thereafter, in the laboratory section, the absorption spectrum of UV-Vis were investigated in both aqueous and alcoholic solvents and solubility of the drug. DFT calculations and laboratory results indicated the preservation of electronic properties of the drug structure in aqueous and alcoholic solvents as well as the increased solubility of the drug in alcoholic solvents compared with aqueous. Correspondingly, this is very important in the drug’s design and synthesis of similar drugs with less harm.

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