Search

Background: Cockroaches play a role in the mechanical transmission of microbial pathogens. This study was designed to determine the isolated bacteria and their susceptibility to conventional antibiotics from brown-banded cockroach, Supella longipalpa, in Qom province, central Iran. Methods: In this cross-sectional study, brown-banded cockroaches were bred in an insectary and caught from hospitals of Qom. The samples were taken from the surface and alimentary canal and then cultured on microbial culture media; next, grown specimens were identified using differential culture media. Finally, after performing diagnostic tests and identifying the bacteria species, their susceptibility to various antibiotics was evaluated. Results: A total of 120 adult cockroaches from the insectary and hospitals were included in the study. Ten bacterial genera were found; nine were Gram-negative and one was Gram-positive. The genus Klebsiella, Enterobacter, Staphylococcus, Citrobacter and Hafnia were isolated only from the hospital strain. On the other hand, Pseudomonas and Escherichia from both groups and other species such as Salmonella, Proteus and Shigella were isolated only from laboratory strains. The highest antibiotic resistance among Gram-positive cocci and Gram-negative bacilli were 100.0% and 98.1% for ampicillin and Ceftazidime, respectively. Conclusion: The results of this study showed that various pathogenic bacteria harbored by brown-banded cockroaches. Moreover, it was found that most of these bacteria belong to the Enterobacteriaceae family, which can be pathogenic and thus threaten human health. [ABSTRACT FROM AUTHOR]

Background and Objectives: Bioremediation is a process to reduce toxic heavy-metals, such as arsenic, in the environment using microorganisms. This study aimed to isolate arsenic remediating microbial strains from garbage leachates and to evaluate the effects of several factors on bioremediation by isolated strains. Materials and Methods: After isolating arsenic-resistant bacteria from garbage leachates and determining their MIC values, Taguchi design of experiments was used to evaluate the effect of arsenic concentration, pH solution, temperature, and contact time on arsenic bioremediation by isolated bacteria. Results: The results revealed that 3 arsenic-resistant strains of genus Bacillus characterized as KL1, KL4, and KL6 had arsenic bioremediation activity. Based on the results, the highest bioremediation of arsenic by Bacillus sp. KL1 was obtained as 77% after 24 hours at 40°C, pH 5, and 150 ppm concentration. However, the maximum bioremediation of arsenic by KL4 (91.66%) and KL6 (88%) was achieved after 24 hours at 40°C, pH 5, and 60 ppm concentration and at 35°C, 90 ppm concentration, pH 5 after 36 hours, respectively. Conclusion: The results presented here may facilitate improvements in the eliminating arsenic from contaminated sites and reducing environmental pollutions. [ABSTRACT FROM AUTHOR]

Background and Objectives: Pyrococcus woesei is a hyperthermophilic archaea and produces a heat stable polymerase (Pwo polymerase) that has proofreading activity., Materials and Methods: In this study, this microorganism was cultured, its DNA was extracted and the pwo gene polymerase was cloned, expressed and purified. The DNA sequence of the cloned gene was verified by sequencing. The pwo polymerase gene consists of 2,328 bps (775 amino acids with about 90 kD molecular weight). Cloning was done by GATEWAY™ Cloning System and for purification of recombinant protein; His6x-Tag was added to the C-terminus of the recombinant protein., Results and Conclusion: We could purify Pwo polymerase enzyme by Ni-NTA resin. PCR assay showed that Pwo polymerase activity is comparable to a commercial Pfu polymerase activity.