Isolation and screening of Bacillus subtilis MJ01 for MEOR application: biosurfactant characterization, production optimization and wetting effect on carbonate surfaces

Abstract The bacterial strain MJ01 was isolated from stock tank water of one of the Iranian south oil field production facilities. The 16S rRNA gene of isolate, MJ01, showed 99% similarity to Bacillus subtilis. The results revealed that biosurfactant produced by this strain was lipopeptide-like surfactin based on FTIR analysis. Critical micelle concentration of produced surfactin in distilled water was 0.06 g/l. Wettability study showed that at zero salinity surfactin can change original oil-wet state to water-wet state, but in seawater salinity it cannot modify the wettability significantly. To utilize this biosurfactant in ex situ MEOR process, economical and reservoir engineering technical parameters were considered to introduce a new optimization strategy using the response surface methodology. Comparing the result of this optimization strategy with the previous optimization research works was shown that significant save in use of nutrients is possible by using this medium. Furthermore, using this method leads to less formation damage due to the incompatibility of injecting fluid and formation brine, and less formation damage due to the bioplugging

Comparison of the patient satisfaction from inpatient and outpatient fissurectomy in Motahari clinic and Shahid Faghihi hospital, Shiraz, Iran

Introduction: Satisfaction of the patients is considered as an important index in evaluating the performance of the hospitals and is highly effective in developing and improving the quality of the provided services .so, the present study aims to compare the satisfaction of the patients suffering from anal fissure from inpatient and outpatient treatments. Method: This cross-sectional study was conducted on 212 subjects who were selected through systematic sampling from the patients with anal fissure referring to Motahari clinic and Shahid Faghihi hospital. In order to compare the patient satisfaction in two inpatient and outpatient groups, 21-item questionnaire was designed in order to assess the patient satisfaction. Independent t-test and chi-square test were used to analyze this data. Results: satisfaction of the inpatients was significantly more than that of the outpatients (P<0.001). The inpatients’ waiting time for operation was significantly longer than that of the outpatients (P=0.029). In comparison to the inpatients, the outpatients were more satisfied with the explanations provided regarding food diets after the operation (P=0.004). Of course, outpatients had felt more stress during the operation compared to the inpatients (P=0.002). Concerning the treatment environment, the outpatients were more satisfied than the inpatients (P0.001), quality, and other services compared to the outpatients (P=0.041). Conclusion: According to the advantages that mentioned, outpatient operations can be a better choice for small surgeries; of course, health planners should pay more attention to its importance and necessity and provide more equipments and welfare facilities in treatment centers

Toxin A and B genes expression of clostridium difficile in the sub-minimum inhibitory concentration of clindamycin, vancomycin and in combination with ceftazidime

Background and Objectives: Antibiotics prescribed for infections have diverse effects on microbiota and the pathogen Clostridium difficile (C. difficile) as the most important antibiotic-associated diarrhea. This study aims to determine the gene expression of toxins A and B at the transcription level in the sub-MIC of vancomycin (VAN), clindamycin (CLI), and ceftazidime (CAZ) alone and in combination. Materials and Methods: The MIC and fractional inhibitory concentration (FIC) of two C. difficile samples (a clinical isolate and ATCC 9689) were determined by microdilution and checkerboard microdilution methods, respectively. The total RNA was extracted from the medium inoculated with ~106 CFU/mL of fresh bacteria in the pre-reduced medium containing ½ MIC of antibiotics alone and ½ FIC of antibiotics in combination. Real-time PCR was performed by sybrGreen methods in triplicate, and the data were analyzed by the comparative ��CT method. Results: All antibiotics except CAZ (alone and in combination) decreased the gene expression of toxins A and B within 24 hours. VAN and CLI reduced toxin gene expression within 24 and 48 hours. However, CAZ alone and in combination with VAN as well as CLI increased the gene expression of toxins A and B. Conclusion: The results confirmed toxin gene transcription and toxin production are associated with the type of isolates and antibiotics, as well as the combined form of antibiotics. This could be the reason which can explain the occurrence of C. difficile infection among patients who were treated with the third generation of cephalosporins alone and in combination with another antibiotic in the form of combinational therapy. © 2020, Tehran University of Medical Science. All rights reserved