somayeh parsania

Gold mine operations release toxic arsenic and other heavy metals into the environment, which can be accumulated in water resources and the food chain. As microbial bioremediation has been a promising method for pollutant removal from contaminated sites, the identification of bacterial communities in arsenic-contaminated resources has recently been in focus. The bacterial communities of tailings dam effluent (TDE) of a gold mine in Iran were analyzed. The bacterial communities were examined using the next-generation sequencing method (Illumina platform) targeting the V3-V4 region of 16S rRNA genes. The 16S rRNA dataset from this study was compared with three arsenic-contaminated groundwater (GW) microbiomes from SRA databases, using the bioinformatics tool QIIME 2. Our findings revealed that the prevalent taxonomic groups observed in all of the samples belonged to Proteobacteria (8.06-45.49%), Bacteroidetes (1.85-50.32%), Firmicutes (1.00-6.2%) and Actinobacteria (0.86-5.09%). Metagenomic analyses showed that Algoriphagus, Rhodobacter, Anaerospora, Limnobacter, Halomonas and Yonghaparkia are the main bacterial genera in TDE. Despite the limited similarities in the prokaryotic community of the samples, the most of the retrieved genera of the TDE are unique and the native bacteria of Iran. Conclusions Long-term exposure to arsenic causes changes in bacterial abundance and richness. This resulted in natural selection and expression of the most compatible genes in existing condition. Although there are similarities in some microbial communities of ground waters, but it can be found some native microorganisms, which was adapted to the harsh environment of TDE.

Background and Presence of extended spectrum β -lactamase (ESBL) genes plays an important role in spreading β -lactam antibiotic resistance in the producing strains of these enzymes. The resistance of gram-negative bacteria, such as Escherichia coli, to different antimicrobial agents, has increasingly been reported. This study was conducted to determine the prevalence of ESBL in Escherichia coli isolates. This analytical cross-sectional study was carried out between March 2013 and February 2014 on 131 bacterial of Escherichia coli which were isolated from clinical patient specimens in general hospitals in Urmia (northwest Iran). The frequency of ESBL producing strains was determined via the combined disk method. The presence of β- lactamase gene of CTX-M-15 in ESBL was assessed by PCR method. clinical presentations of infection were UTI in 108 cases (82.44%), septicemia in 15 cases (11.45%), wound infection in 7 cases (5.34%), and meningitis in 1 case (0.76%). Frequency of ESBL positive in Escherichia coli isolates was 55 cases (41.98%) of which 23.63% were positive for CTX-M-15 β -lactamases resistance gene. The rate of ESBLs producing strains is highly increasing, therefore, using an appropriate treatment protocol based on the antibiogram pattern of the strains is highly recommended