Background: To determine the species distribution, updated drug susceptibility patterns and genes conferring resistance in clinical vancomycin resistant enterococcal (VRE) isolates. Methods: Clinical enterococcal isolates collected during 7 months, from September 2005 to April 2006 from hospitalized patients and outpatients were studied. Twenty five VRE were isolated from 450 enterococci samples (5.6%). VRE isolates were subjected to antibiotic susceptibility tests. Genotype of these isolates was determined by PCR. Results: All of the isolates were E. faecium and carried the vanA gene. Antibiotic susceptibility tests showed that the isolates were resistant to ampicillin 25(100%), ciprofloxacin 25(100%), gentamicin 24(96%), erythromycin 25(100%), tetracyclin 10(40%) and chloramphenicol 2(8%). Conclusion: VRE strains were resistant to three antibiotics and were susceptible to new antibiotics linezolid and dalfopristin - quinupristin. Switching to treatment with these antibiotics would relieve the problem for a short time.

15, 2018-Accepted: July 3, 2019) ABSTRACT Pathogenic fungi and bacteria infect plants and inflict important diseases leading to major economic losses. The use of beneficial Lactic Acid Bacteria (LAB) in controlling different type of human and plant pathogens, has drawn worldwide attention. The aim of this study was to assess the antifungal activity of secreted substances from two newly isolated strains of Enterococcus faecium (Kx185054 and Kx185055) from Persian oak tree sap in controlling Fusarium oxysporum and Alternaria solani fungi and Curtobacterium flaccumfaciens pv. flaccumfaciens and Pseudomonas syringae pv. tomato bacteria. Secreted substances from Enterococcus faecium strains were added to the fungi and bacteria culture media at different concentrations and the inhibition zone was recorded in three replicates. Results of this experiments together with that of scanning electron microscopy imaging revealed that secreted substances had a significant antimicrobial activity. Fungal mycelia/spores and bacterial cells became deformed, shrunken, and distorted following treatment with secreted substances from Enterococcus faecium strains, suggesting that Enterococcus faecium secretes antimicrobial chemicals/peptides preventing fungal strictures from germination, growth and penetration. The results of this study may help in elucidating the potentials of newly isolated Enterococcus faecium strains from oak tree and identifying the genes coding for antifungal peptides.

Background: Bacteriophages are viruses that infect bacteria. Bacteriophages are widely distributed in various environments. The prevalence of bacteriophages in water sources, especially wastewaters, is naturally high. These viruses affect evolution of most bacterial species. Bacteriophages are able to integrate their genomes into the chromosomes of their hosts as prophages and hence transfer resistance genes to the bacterial genomes. Enterococci are commensal bacteria that show high resistance to common antibiotics. For example, prevalence of vancomycin-resistant enterococci has increased within the last decades. Methods: Enterococcal isolates were isolated from clinical samples and morphological, phenotypical, biochemical, and molecular methods were used to identify and confirm their identity. Bacteriophages extracted from water sources were then applied to isolated Enterococcus faecium (E. faecium). In the next step, the bacterial genome was completely sequenced and the existing prophage genome in the bacterial genome was analyzed. Results: In this study, E. faecium EntfacYE was isolated from a clinical sample. The EntfacYE genome was analyzed and 88 prophage genes were identified. The prophage content included four housekeeping genes, 29 genes in the group of genes related to replication and regulation, 25 genes in the group of genes related to structure and packaging, and four genes belonging to the group of genes associated with lysis. Moreover, 26 genes were identified with unknown functions. Conclusion: In conclusion, genome analysis of prophages can lead to a better understanding of their roles in the rapid evolution of bacteria.

Background & Objective: Enterococci are increasingly recognized as important pathogens in clinical settings due to their intrinsic and acquired antibiotic resistance. The aim of this study was to investigate the prevalence of Enterococcus (E.) faecalis and E. faecium in clinical samples, their antibiotic resistance patterns, and the correlation between vancomycin resistance and the presence of the vanA gene in both species. Methods: A total of 120 isolates were identified from clinical samples. Phenotypic specification was confirmed by targeting D-alanine-D-alanine ligases specific for E. faecalis and E. faecium using PCR analysis. Antibiotic resistance was determined by antimicrobial susceptibility testing using disk diffusion method. The presence of van genes was investigated by multiplex PCR analysis. Real-time RT-PCR was used to determine the expression of vanA gene among vancomycin-resistant isolates. Results: In this study, 82 E. faecalis (68.3%) and 38 E. faecium (31.6%) isolates from a total of 120 clinical samples were identified. Antimicrobial susceptibility testing revealed increased resistance rates among E. faecium, with resistance to ampicillin at 89.5% and penicillin at 84.2%, while E. faecalis showed lower rates of resistance at 5.8% and 7.2%, respectively. Multiplex PCR analysis confirmed that 54.1% of E. faecalis and 69.2% of E. faecium resistant isolates contained vanA gene. Notably, vancomycin-treated isolates exhibited 8.6-fold increase in vanA gene expression compared to untreated E. faecalis, while E. faecium showed 2.6-fold increase. Conclusion: This study found a high prevalence of vancomycin-resistant Enterococcus (VRE) isolates, with majority carrying vanA gene. Resistance rates to multiple antibiotics were significantly higher in E. faecium compared to E. faecalis. Furthermore, vanA gene expression was notably increased in VRE isolates treated with vancomycin. The research highlights the genetic and environmental factors driving VRE emergence and proposes potential treatment strategies to combat this public health concern.