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The Pseudomonas aeruginosabacterium, which is considered a nosocomial infectious agent, changes its structure due to exposure to various antibiotics and becomes relatively resistant to them, which makes it difficult to treat diseases caused by this bacterium. This study can identify the main genes that make biofilm and allow researchers to inhibit the rate of biofilm formation and spread by making antibiotics that affect these genes, and ultimately improve the patient by inhibiting bacterial growth. In this study, clinical isolates were collected from Afzalipour Hospital in Kerman, Iran and identified as phenotypic and then genotypic. Fifty-five clinical isolates of P. aeruginosawere confirmed. Antibiogram test was performed for meropenem, amikacin, ampicillin–sulbactam, cefotaxime, levofloxacin, rifampin, and tigecycline antibiotics. The ability to form biofilms of isolates was determined by microtiter plate and staining using crystal violet and then spectrophotometry in OD 490 nm. PCR was performed to identify the frequency of pslAand pelBgenes. The data showed that the highest age group involved 1 to 15 years included 19% and the lowest age group 26 to 35 years included 5%. The frequency of pslAand pelBgenes was 34.5% and 65.5%, respectively, and the range of drug resistance for the mentioned antibiotics was between 72 and 100%. Since the frequency of the pelBgene is about twice as high as that of pslA, it may be concluded that in most of the isolates studied, Psl often has a disorder or that the intracellular level of c-di-GMP has increased sharply.

The emergence of pathogenic bacterial strains resistant to currently available antimicrobial agents is a universal problem of arising importance. Antibiotic resistance is accelerated by the misuse and overuse of antibiotics, as well as poor infection prevention and control. One way of overcoming antibiotic resistance is to produce new and diverse antibiotics. A new quinolones derivative (in this article named antibiotic A) was synthesized, and the antimicrobial effects of this synthetic antibiotic and conventional quinolones on planktonic forms of mentioned bacteria were evaluated by disk diffusion and well diffusion methods. Then, minimum inhibitory concentration and minimum bactericidal concentration values were determined by the micro-broth dilution technique. Effects of the new quinolones were studied on biofilm formation and biofilm destruction and also the inhibition of the dehydrogenase enzyme. The greatest destructive and the highest inhibitory effects of antibiotic A were observed on the biofilm formation of P. aeruginosa(92.01 and 95.02%, respectively). Also, the maximum reduction in metabolic activity of bacteria in the biofilm was observed for B. cereus(86.21%) and P. aeruginosa(81.01%). Among ciprofloxacin-resistant bacteria, the highest inhibitory effects of antibiotic A were observed on biofilm formation of resistant E. coli(97.02%), and the most incredible destruction was observed on resistant S. aureusbiofilm (92.01%). This study showed that synthetic antibiotic A represents better antibacterial effects than conventional antibiotics, but it needs further investigation.

Food spoilage by microorganisms not only leads to economic and energy wastage but can even cause health-related problems in consumers and therefore research and development on food preservation methods is essential. Among the non-thermal technologies in this regard is radiation. This study investigates four foodborne bacteria including Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureusand Bacillus cereusin poultry meat, and the effect of two different combination of radioactive materials americium-radium (Am-Ra) and americium-beryllium (Am-Be) rays on them at different times. Also, the effect of the mentioned rays on the spores of B. cereusand reduction of antibiotic resistance of all four bacteria is reported. The microbial population of S. aureusand E. colidecreased by 35% and 40% after 4 days of americium and radium irradiation, respectively. This value was 66.6%, 95%, 91.6% and 94.6% for S. aureus, E. coli, K. pneumoniaeand B. cereusafter 7 days of americium-beryllium irradiation, respectively. Irradiation also reduced antibiotic resistance in S. aureus. According to the results obtained in this study, it can be concluded that the use of radiation by the source of americium-beryllium with 4.7 Ci has been effective in reducing spoilage bacteria and inhibiting their growth. Also, due to the effect of irradiation for 5 days by americium-beryllium with 4.7 Ci activity in 100% removal of spores of B. cereus, this technique will be effective in sanitizing and improving the quality and safety of food with spores.

The Bacillus pumilusSG isolated from soil samples at the Persian Gulf was analyzed for its ability to produce biosurfactant. Various screening techniques were used for evaluating biosurfactant production and confirming biosurfactant presence in the culture supernatant. Most n-alkanes in the bacterial culture media were effectively degraded in the presence of biosurfactant acquired from the bacteria. The highest interfacial tension (IT) reduction (42 mN/m) was obtained at 24-h fermentation time (exponential phase) and did not change significantly afterwards. The glycolipid structure of the biosurfactant was revealed through NMR and FTIR spectroscopy analysis. Two-level factorial design was then applied for optimization of biosurfactant production, where a maximal reduction of culture broth IT (30 mN/m) acquired in the presence of crude oil (0.5%, v/v), NaNO3(1 g/L), yeast extract (1 g/L), peptone (2 g/L) and temperature of 25 °C. The produced biosurfactant that exhibited a critical micelle concentration of 0.1 mg/ml was thermally stable. The glycolipid biosurfactant also displayed significant antibacterial activities against both Gram-positive and Gram-negative bacteria. The maximum inhibition of glycolipids biosurfactant was found against Acinetobacterstrains (zone of inhibition, 45 mm). In addition, antibiofilm activities with a 50–90% biofilm reduction percent were indicated by the glycolipid biosurfactant. In conclusion, the glycolipid biosurfactant produced by B. pumilusSG revealed a wide range of functional properties and was verified as a good candidate for biomedical application. In conclusion, the glycolipid biosurfactant produced by B. pumilusSG showed a wide range of functional properties in this study, and in the case of further in vivo studies, it can be investigated a good candidate for biomedical applications such as use against biofilm or in pharmaceutical formulations.

Acid mine drainage (AMD) is an environmental pollution that is generated from the oxidation of sulfide minerals that exist in the mine dumps. AMD causes pollution of surface and underground waters and lead to distribution of heavy metals into the environment. The aim of this research is isolation and identification of heterotrophic iron and sulfur-oxidizing bacteria from AMD of Sarcheshmeh copper mine. The mine samples were collected from six different locations of the mine. Iron and sulfur-oxidizing heterotrophic bacteria were quantified with serial dilution and most probable number methods. Heterotrophic oxidizing bacteria were screened by three methods: decrease in pH, sulfate ion production activity and growth rate. Most efficient heterotrophic oxidizing bacteria were identified by molecular method. The results of this research show that the maximum quantity of these bacteria in Sarcheshmeh copper mine relate to dumps number 32 and 17 with value 8 × 10 and 5.9 × 10, respectively. Thirty two strains were isolated from six different locations of this copper mine and after screening tests 15 effective strains were selected and 8 strains were identified by molecular method. The results of the molecular identification showed that eight strains belong to: Bacillus thuringiensis strain DP26-1, Bacillus sp. strain DP-15-4, Pseudochrobactrum sp., Brevundimonas sp., Brevibacillus formosus, Sphingomonas ginsenosidimutans, Pseudomonas brassicacearum, Sphingomonas paucimobilis. Most efficient heterotrophic oxidizing bacteria related to DP-17-3 and DP-30-1 strains that produce high percentage of sulfate ion (270 and 223 ppm) also decrease dramatically the pH (4.2 and 4.9). Application of these bacteria in bioleaching process can enhanced efficiency of metal extraction in this copper mine.

Phenol is one of the major aromatic and carcinogenic pollutants. Phenol degrader bacteria from the coal tar mine of Zarand have been identified with the bacterial growth assayed in different concentrations. Four samples were collected from different sites of the mine. Total heterotrophic and phenol-degrading bacteria were quantified and the results indicated that most of phenol degrader bacteria aggregated in the sludge aggregate site. Eleven phenol degrading bacteria were isolated that were capable of degrading 200 ppm phenol in 7 d, 6 bacterial strains were selected for capability of growth on more concentration of phenol and biochemical characteristics. Finally, two strains named isolates 42P and 53P were selected for analysis of 16S rRNA sequences. Strain 42P belongs to Chryseobacterium indologenes AHB42P while Strain P53 belongs to Pseudomonas putida AHB53P which is capable of degrading 1,800 ppm phenol. The results support the idea that environments in mines can serve as a source of bacterial strains for purposes of bioremediation.

Soil pollution by petroleum hydrocarbons is a widespread problem which has disturbing effects on the composition and diversity of microbial communities. The aim of this research is study the response of soil microbial communities to crude oil contamination. This research examines three microcosms: unpolluted, polluted and polluted with addition of (nitrogen and phosphorus as nutrients). Some factors were analyzed in each microcosms for 120 days include: enumeration of heterotrophic and degrading bacteria, enzyme assay and degradation of crude oil. Desert soil has an abundance in degrading bacteria (2 × 106cfu/g), however, crude-oil degrading bacteria were lower than heterotrophic bacteria. The density of crude-oil degrading bacteria declines until the day 60th and after this time they increased. The highest dehydrogenase activities are found in the polluted microcosms amended with nutrients. Hydrocarbon degradation is lowest in the desert microcosm (40%). The results of this research confirmed a significant relationship between (Most Probable Number) of heterotrophic bacteria and degradation of crude oil. The results obtained in this research may be useful for developing strategies for bioremediation of pollution of different soil types.

Phenol and phenolic compounds are environmental pollutants present in industrial wastewaters such as coal tar, oil refineries and petrochemical plants. Phenol removal from industrial effluents is extremely important for the protection of environment. Usually, phenol degradation is carried out by physicochemical methods that are costly and produce hazardous metabolites. Recently, phenol biodegradation has been considered. Yeasts are the most important phenol biodegraders. In this study, the phenol-degrading yeast from environmental samples (soil and wastewater) was isolated from the coking plant of Zarand, Kerman. Then total heterotrophic yeasts were counted. The soil samples had higher rates of yeast degrader, in comparison to wastewater samples. After three passages, four yeasts (K1, K2, K7 and K11) that had the highest growth rate were selected for further study. Also, these yeasts were able to remove phenol measured by Gibbs reagent. The effect of four different concentrations of phenol (50, 125, 200 and 275) mgL−1was measured and three degradation patterns in these yeasts were observed. The hydrophobicity and emulsification activity were measured in all eleven yeasts. Finally, strong yeasts in phenol degrading yeasts were identified by molecular method using amplification of 18S rRNA gene region. The sequencing results showed that these isolated yeasts belonged to Candida tropicalisstrain K1, Pichia guilliermondiistrain K2, Meyerozyma guilliermondiistrain K7 and C. tropicalisstrain K11.