Showing 15 results for Bacteria
K Naddafi, S Rezaei, R Nabizadeh, M Younesian, H Jabbari,
Volume 1, Issue 2 (3-2009)
Abstract
Background and Objectives: Atmospheric transport is a key mode of microbial dispersal and the transmission of airborne microbe can have significant impacts on human health. The main objective of this study was to determine the concentrations of airborne bacteria in a children.s hospital.
Materials and methods: Three sampling points were selected. Airborne bacteria were collected with 6 days interval at each location using Quick take 30® sampler at an sampling rate of 28.3 l min-1 from November 2007 to March2008.
Results: The results showed that the highest indoor density of bacteria was 429 CFU/m3 that founded in oncology ward. Bacteria identified were representative of normal flora of the skin, respiratory and gastrointestinal tracts.
Conclusion:Our analysis revealed that colony of bacteria in 14% in patient room exceeded available guideline value for indoor air quality. That 11% cases was found in the oncology ward.
M.h Dehghani, M Ghaderpoori, M Fazlzadeh, S Golmohamadi,
Volume 2, Issue 2 (9-2009)
Abstract
Backgrounds and Objectives:Safe drinking water providing is one of the main purposes in the community. Development and improvement of community is related to the public health. In this study !we studied the bacteriological quality of 116 villages under coverage of the water and wastewater companies in rural areas of Saqqez in.1386
Material and Methods:Drinking water of these rural areas have provided of deep, semi-depth- wells and spring water sources. Because in numerous rural areas both sources of drinking water and in some of them different sources of drinking water were used (old and new storage water source), in general, 359 samples were collected and transferred to the laboratory for testing to evaluate its quality. We also used linear Regression statistical analysis for collected data.
Results:results show that residual chlorine in drinking water in 33.88 percent of rural areas population were in range 0.2-1 mg/l. For 98.3 percent of the seqqez rural population, the turbidity was lower than the maximum permissible levels of drinking water standards of Iran (5 NTU). There was no any E.coli contamination in 88 percent of drinking water in saqqez rural areas.
Conclusion:Based on WHO guidelines concerning the microbial quality of water published in 2006! the average indicator for lack of E.coli in water of rural areas of seqqez was 88 percent and water is safe or good for drinking.
E Taheri, M Vahid Dastjerdi, M Hatamzadeh, A Hassanzadeh, F Ghafarian Nabari, M Nikaeen,
Volume 2, Issue 4 (3-2010)
Abstract
Backgrounds and Objectives: Drinking water quality after treatment and before reaching the consumer could be affected by distribution pipes, service lines and Home devices. The structure of water coolers, a home device that are widely used in warm months of the year, could potentially affect the quality of drinking water. The aim of this study was to assess the microbial and chemical quality of water from conventional water coolers.
Materials and Methods : Water samples were collected from 29 water cooler systems at the Isfahan university of medical sciences. 29 control samples also obtained from the nearest drinking water taps. All samples were examined for total heterotrophic bacteria and physicochemical parameters including temperature, ph, turbidity and heavy metals.
Results: All samples from the water cooler systems complied with the EPA guidelines for total heterotrophic bacteria count. There were no significant differences between the levels of heavy metals in water samples from the water cooler systems and taps. There was only a significant difference between the level of Cu in the water samples from cooler systems and taps
Conclusion: The overall results of this study indicated that the use of water cooler systems from hygienic point of view could not cause any problems for consumers
P Bahmani, R Rezaei Kalantary, M Gholami, A Jonidi Jafari, Z Javadi,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives: Reactive dyestuff has potential of toxicity, carcinogenesis and mutagenesis for mammals and aquatic organisms. The current physical and chemical methods such as adsorption, coagulation, precipitation, filtration and ... can been used for removing of dyestuff. Biological treatment which is effective and economic for decontamination of dyestuff wastewaters was preferred because of limitation and difficulty of physicochemical methods. In order to investigate the trend of pollution reduction of color compounds, ability of Remazol Black-B dyestuff removal from aqueous medium by bacterial consortium under anoxic conditions was studied.
Materials and Methods: The mix culture of bacteria from textile industries activated sludge was enriched in luria broth medium containing RB-B dyestuff as a carbon source. Then biodegradation was assessed in 4 batch reactors. Microbial population of bacterial and decolorization quantities of samples were detected by MPN and UV-Vis spectrophotometer.
Results: Decolorization efficiency by the bacterial consortium was obtained more than 99% for 50 and 250 mg/L concentrations in 72 and 144 h (3 and 6 days) respectively, while for the initial concentration of 500 mg/L was 98.1in 240 h (10 days) of biodegradation period. Dyestuff reduction rate after completed removal was about 0.69, 1.74,2 mg/L/h for initial concentration of 50, 250, 500 mg/L respectively.
Conclusion: Results showed that Alcaligenes denitrificans and Alcaligenes xylosoxidans bacteria
which were isolated from activated sludge have good potential of RB-B dyestuff removal and this removal is depending on primary concentration of dye. Removal efficiency increased as primary concentration went up.
M Manshouri, A Yazdanbakhsh, M Sardar, A Sheykh Mohammadi,
Volume 3, Issue 4 (1-2011)
Abstract
Backgrounds and Objectives: Reactive dyestuff has potential of toxicity, carcinogenesis and mutagenesis for mammals and aquatic organisms. The current physical and chemical methods such as adsorption, coagulation, precipitation, filtration and ... can been used for removing of dyestuff. Biological treatment which is effective and economic for decontamination of dyestuff wastewaters was preferred because of limitation and difficulty of physicochemical methods. In order to investigate the trend of pollution reduction of color compounds, ability of Remazol Black-B dyestuff removal from aqueous medium by bacterial consortium under anoxic conditions was studied.
Materials and Methods: The mix culture of bacteria from textile industries activated sludge was enriched in luria broth medium containing RB-B dyestuff as a carbon source. Then biodegradation was assessed in 4 batch reactors. Microbial population of bacterial and decolorization quantities of samples were detected by MPN and UV-Vis spectrophotometer.
Results: Decolorization efficiency by the bacterial consortium was obtained more than 99% for 50 and 250 mg/L concentrations in 72 and 144 h (3 and 6 days) respectively, while for the initial concentration of 500 mg/L was 98.1in 240 h (10 days) of biodegradation period. Dyestuff reduction rate after completed removal was about 0.69, 1.74,2 mg/L/h for initial concentration of 50, 250, 500 mg/L respectively.
Conclusion: Results showed that Alcaligenes denitrificans and Alcaligenes xylosoxidans bacteria
which were isolated from activated sludge have good potential of RB-B dyestuff removal and this removal is depending on primary concentration of dye. Removal efficiency increased as primary concentration went up.
Edris Hoseinzadeh, Mohammad Reza Samargandi, Mohammad Yosef Alikhani, Ghodratollah Roshanaei, Ghorban Asgari,
Volume 5, Issue 3 (10-2012)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Along with the rapid development of human life,
controlling harmful effects of
microorganisms would be unavoidable. The objective of this study was to
evaluate antibacterial efficacy of zinc oxide nanoparticles on different
microbial strains.
Material and Methods:
This experimental study was done using gram negative and gram positive bacteria
in nutrient media. Nanoparticle characterization was determined using X-ray
diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM).
Bacterial sensitivity to nanoparticles was tested using a disk diffusion test
and minimum inhibitory concentration (MIC). Time-kill studies and other tests
were carried out using 108 CFU/mL of bacteria at baseline. A point of zero
charge, pHzpc, of nanoparticle was investigated using the batch equilibration
method. Obtained data were managed by SPSS Ver.16 and were analyzed through the
Pearson, analysis of variance (ANOVA) and Student's independent t-tests. 0.05
was selected as significant level for all tests.
Results:
Characterization results from XRD, SEM, and TEM showed that particles are in
nano range and they do not contain any discernible crystalline impurity. The
average ZnO nanoparticles diameter was 20 nm. The pHZPC for ZnO was found to be
7.51. The P. aeruginosa strain exhibited larger diameter inhibition zone (DIZ)
to ZnO nanoparticle compared with other strains. Population of P.aeroginosa for
2 x MIC concentration was reduced to zero in the presence of nano ZnO within
150 min. The bacterial CFU had significant difference with contact time,
nanoparticles loading, and bacterial strain (P<0.001).
Conclusion: This study
demonstrated that antibacterial activity of ZnO can be a candidates for the
elimination of gram negative and gram positive bacteria, particularly in
nasocomial infection agent control.
Abdolmotaleb Seid-Mohammadi, Hossein Movahedian Attar, Mahnaz Nikaeen,
Volume 5, Issue 4 (2-2013)
Abstract
MicrosoftInternetExplorer4
Background and Objectives: Contamination of drinking water sources with nitrate may
cause adverse effects on human health. Due to operational and maintenance
problems of physicochemical nitrate removal processes, using biological
denitrification processes have been performed. The aim of this study is to
evaluate nitrate removal efficiency from drinking water using autotrophic
denitrifying bacteria immobilized on sulfur impregnated activated carbon in a
fluidized bed bioreactor.
Materials and Methods: After impregnating activated carbon by sulfur as a microorganism carriers and
enrichment and inoculation of denitrifying bacteria, a laboratory-scale
fluidized bed bioreactor was operated. Nitrate removal efficiency, nitrite,
turbidity, hardness and TOC in the effluent were examined during the whole experiment
under various conditions including constant influent nitrate concentration as
90 mg NO3--N/l corresponding to different HRT ranging from 5.53 to 1.5 hr.
Results: We found
that the denitrification rates was
depended on the hydraulic retention time and the nitrate removal efficiency was
up to 98% and nitrite concentration was
lower than 1mg/l at optimum HRT=2.4 hr respectively. Moreover, there was no
difference in hardness between influent and effluent due to supplying sodium
bicarbonate as carbon source for denitrifying bacteria. However pH, TOC, hardness, and turbidity of
the effluent met the W.H.O guidelines for drinking water.
Conclusion: This
study demonstrated that an innovative carrier
as sulfur impregnated activated carbon could be
used as both the biofilm
carrier and energy source for
treating nitrate contaminated drinking water in the
lab-scale fluidized bed bioreactor.
Mahdi Jahangiri, Masoud Neghab, Vahid Kahdemain, Reza Rostami, Ali Karimi, Mandana Aghabeigi, Abasali Kasayee Nasab,
Volume 6, Issue 1 (5-2013)
Abstract
Background and Objectives: Wastewater contains various pathogens including viruses, bacteria, fungi, etc. These microorganisms can easily become airborne during normal operations of wastewater treatment plant and contaminate the neighborhood environment. The aim of this study was to investigate the type and density of bioaerosols in a petrochemical wastewater treatment plant in Iran.
Materials and Methods: In this cross sectional study, bioaerosols density was measured in different units of a petrochemical wastewater treatment plant according to the NIOSH 0800 method and the values measured were compared with background level (control area). For this purpose, air samples were collected on blood agar and dextro agar in Andersen single-stage sampler with air flow of 28.3 l/min for 10 minutes. Samples collected were shipped to the laboratory immediately and were incubated for 48 hours. Then, incubated samples were counted for colonies concentration.
Results: Average concentration of bacteria and fungi bioaerosols measured were 731.70±185.49 and 28.43±10.58 (M±SD) CFU/m3 respectively throughout the wastewater treatment plant units. These values were 35 and 1.45 times higher than background level (Control area). The differences between average concentrations of bacteria in all units of wastewater treatment plant with control area were statistically significant.
Conclusions: Generally, it was found that the density of bioaerosols, especially bacteria was much higher than the background level. The maximum density was measured at aeration chamber, where the emission of bioaerosols could be reduced through replacing nozzle diffused aeration system.
Mohammad Sadegh Sekhavatjou, Roya Zekavati, Mohsen Peymani Froshani,
Volume 6, Issue 3 (12-2013)
Abstract
Objectives: Many of non-respiratory and respiratory disorders are associated with bioaerosols in indoor and outdoor air. The best conditions for bioaerosols life are high humidity and moderate temperatures, which exist usually in indoor spaces such as the prisons, where density of individual is high. Pathogen spreading centers cause the prisoners health at risk of disease outbreaks through airborne and breathing, sneezing, and coughing. Therefore, the aim of this research work was to measure concentration of particulate matters and also to identify and determine bacteria existing in the prisoners breathing air at high-density areas in one of the prisons and their relationship with each other.
Materials & Method: we conducted this research during summer and winter of 2012. We used TSI apparatus for collecting particles (PM2.5 and PM10). Blood agar and EMB agar media were applied to measure bacteria in indoor air (bedchambers and clinical admission wards) of the prison. According to NIOSH 0800 method, High volume pump with 28.3 L/min flow and a Single-stage Anderson Impactor were used for sampling. The time of measuring for each plate was 2.5 min. Finally, the data achieved were analyzed using SPSS after counting and detecting bacterial colonies grown and determining its density (CFU/m³) for two consecutive seasons of summer and winter. The tests analyzed by SPSS were ANOVA, Post hoc, correlation, and Pearson correlation tests.
Results: Amounts of particulate matter in bedchambers were exceeded than 24-hour EPA limits, while it was less than the limits in clinical admission wards. Gram-positive and gram-negative bacteria were found in three bedchambers (50% of the bedchambers) however, gram-positive bacteria were cultivated only in three bedchambers. The maximum bacterial contamination was measured at the main Lobby of the prison and bedchamber II and the minimum value was observed in admitted patient and TB patient wards. Results showed that there is no significant relationship between the particulate matters and the bacterial density during neither summer nor winter, but there is a strong and direct relationship between the prisoners population density, ventilation systems, and bacterial density n indoor air of the studied prison.
Conclusion: Based on the results, the maximum contamination load and exceeded concentration was observed in public sections and bedchambers. This findings were attributed to the daily entry of new prisoners, high population density in prison, presence of ill prisoners, prisoners with hidden respiratory disease showing no symptoms yet, old building, climatic conditions of the region, low efficiency of ventilation systems, and influx of particulates. To filter and purify prison indoor air, it is crucial to take serious action plans such as reducing criminal population density, sanitary and engineering measures
Masoumeh Golshan, Simin Nasseri, Mahdi Farzadkia, Ali Esrafili, Roshanak Rezaei Kalantary, Leila Karimi Takanlu,
Volume 7, Issue 2 (10-2014)
Abstract
Background and Objectives: The use of surfactants enhance the bioavailability of nonbiodegradable contaminants such as PAHs. Biosurfactants are more environmental friendly. In this study the ability of removing phenenthrene from soil by biosurfactant was assessed and compared with that of chemical surfactant. Materials and Methods: A soil sample free of any organic or microbial contamination was artificially spiked with phenanthrene at two concentrations. Then, mineral salt medium at constant concentration of chemical surfactant TritonX-100 and rhamnolipid MR01biosurfactant was added to it in order to have the proportion of 10% w:v (soil:water). A microbial consortium with a potential of phenanthrene biodegradation was inoculated to the soil slurry in two densities (OD=1 and 2) and then it was aerated on a shaker. After eight weeks, the residual concentration of phenanthrene in the soil was extracted by ultrasonic and was analyzed using HPLC. MPN test was used for measuring microbial population. This study was conducted based on the two level full factorial design of experiment. Results: It was found that chemical surfactant exhibited higher PHE removal efficiency than the biosurfactant. Using 120 mg/L of TritonX-100 and rhamnolipid, the PHE removal for the soil contaminated with 50 mg PHE/kg dry soil was 98.5 and 88.7% respectively, while the removal efficieny was decreased to 87 and 76% respectively for the soil contaminated with 300 mg PHE/kg. In the absence of surfactant, the removal efficiency at concentrations of 50 and 300 mg PHE/kg dry soil was achieved 60.76 and 51% respectively. The phenanthrene removal efficiency in OD=2 was more higher than OD=1. In the presence of rhamnolipid, the maximum microbial populations was observed in the second week, while it decreased in the presence of TritonX-100. Conclusion: Use of biosurfactants can be considered as a suitable option in low level pollutant sites. Chemical surfactants as ex-situ has achieved more satisfactory results in high level contaminant sites.
M Safari, S Ahmady-Asbchin, N Soltani,
Volume 7, Issue 3 (5-2014)
Abstract
Background and Objective: Petroleum hydrocarbons are a bunch of pollutants hazardous to the environment. Nowadays, biodegradation of petroleum contaminants is considered as one of the most efficient and most cost effective methods of removing oil contamination from the environment. The main objective of this study is to investigate the potential of cyanobacterium Schizothrix vaginata ISC108 in the biodegradation of crude oil and to evaluate oil effects on growth rates, dry weight, and chlorophyll content. Material and Methods: In this experimental study, the cyanobacterium Schizothrix vaginata ISC108 was obtained from the algal culture collection of Research Institute of Applied Science, ACECR, Tehran, Iran. First, purification of the cyanobacterium was performed using agar plate method on solid medium of BG11. Growth rate, chlorophyll content and dry weight of cyanobacteriaum was measured using spectrophotometry method. The biodegradation rate of crude oil was calculated using gas chromatography (GC) analysis. Results: Measuring the growth rate of cyanobacterium Schizothrix vaginata at 1% treatment of crude oil and control samples showed that the growth of cyanobacterium in the presence of crude oil as the sole carbon source increases at the same rate as the control sample. Moreover, it was found that increasing the concentration of crude oil will result in increasing dry weight of Schizothrix vaginata however, and the chlorophyll content reduced in various crude oil treatments. The average biodegradation of petroleum hydrocarbon after 14 and 28 days of treatment was 54.78 and 93.98% respectively. Conclusions: It was found that cyanobacterium Schizothrix vaginata ISC108 has great potential in biodegradation of crude oil. Therefore, since oil is a product toxic to biological systems and is one of the main pollutants of bioecosystem, it has a great potential to be used as an indicator to eliminate pollution in contaminated areas.
H Meskini, E Sadeghi, A Nosrati, P Nosrati, M Bashiry,
Volume 9, Issue 2 (9-2016)
Abstract
Background and Objectives: Money as a common tool is exchanged between people all over the world. Thus, it can be a source of chemical and biological contaminations causing serious diseases. The purpose of this research was to determine bacterial contamination of the currency notes and coins collected in Kermanshah.
Materials and Methods: 160 currency notes and 96 coins were randomly chosen from different jobs and parts of the city. Total count experiment was done and bacteria were identified and isolated through standard methods.
Results: Average total count in 1000, 2000, 5000, 10000, and 20000 Rials currency notes were 147.6, 147.8, 148.5, 96.3, and 87.9 and in 500, 1000, and 2000 Rials coins were 104.66, 77.66, and 96.56 CFU/cm2, respectively. The research showed that currency notes carries more bacterial load than coins (P<0.05). Additionally, contamination to E. coli on money (13.7 %) and on coins (3.9%) were at maximum levels while Pseudomonas on currency notes was at the minimum level (1.6%) and coins contained 0.2% Enterobacter that was at the lowest amount.
Conclusion: In summary, the most important microorganisms isolated from currency notes and coins (E.coli and Staphylococcus aureus) were pathogenic, causing serious food poisoning and gastroenteritis infectious. Therefore, preventing food from cross contamination with money is necessary.
M Montazer, N Soleimani, R Zendehdel, K Etemad, M Abtahi Mohasel, M Malmir,
Volume 11, Issue 2 (9-2018)
Abstract
Background and Objective: Bacterial exposure in hospitals due to the presence of pathogens in hospitals is one of important health problems for medical staff. The World Health Organization (WHO) reported a global outbreak of hospital infections from 5.7% to 19.1% in the 2011 report. The aim of this study was to identify bacterial bioaerosols in nursing stations in a public hospital in Tehran to determine the occupational hazards of them.
Materials and Methods: This cross-sectional study was conducted three times at fifteen nursing station in 15 different departments of a public hospital in Tehran. 45 samples were prepared on three culture media including Mackangi Agar, nutrient agar and Manitol Salt Agar. Air samples were prepared according to NIOSH 0800 method by a bacterial sampler with a flow rate of 28.3 L/min for 5 min. Samples were analyzed by microbial screening test.
Results: Mean of the bacterial infection was 180.03±125.27 CFU/m3. The results showed that there were gram positive staphylococcus aureus in the all air samples of nursing stations. Moreover, in 26.7% of occupational exposure nursing stations with Acinetobacter Iwoffii was observed as the most common gram negative bacteria.. Maximum bacterial number was found in orthopedic nursing station (399.99 CFU/m3) and heart transplant nursing station had the minimum bacterial infection (43.73 CFU/m3).
Conclusion: Eighty percent of occupational exposure in the samples had higher exposure to bacterial pathogens than the standards set by ACGIH (75 CFU/m3). Due to the presence of Staphylococcus aureus, E. coli and Acinetobacter Iwoffii in nursing stations, there was a risk of hospital infections in health care workers. It seems unsuitable surface sterilization and lake of useful engineered controlling methods has led to bio aerosol scattering in the air of studied stations.
Elham Asrari, Hedieh Deyhim,
Volume 15, Issue 2 (8-2022)
Abstract
Background and Objective: The application of ultraviolet photolysis in the removal of microbial contamination can develop the use of wastewater sources. In this research, the efficiency of UVC-LED for removing Escherichia coli was evaluated in pulsed radiation mode with continuous radiation.
Materials and Methods: In order to conduct this research, 4 UVC-LEDs with a short wavelength of 12 MW were used to produce ultraviolet rays. LEDs create waves with a wavelength of 260-280 nm. The distance between the LED and the plates was considered to be about 0.5 cm, 1 cm, and 2 cm. In order to investigate the effect of discontinuous radiation on UVC-LED performance, 2 Hz and 1 Hz frequency were used. In this case, the power source is connected 2 times and 1 time respectively in every second. The variables of radiation time (t) in seconds, radiation distance (d) in centimeters, and radiation frequency (f) in Hz were used for valuation.
Results: The results showed that in discontinuous irradiation, although the effectiveness increases with the increase of irradiation time, and practically at times higher than 280 seconds, bacteria do not remain in the samples, but the performance of discontinuous irradiation compared to continuous irradiation in removing bacteria at irradiation intervals of 1 cm, 0.5 cm and time 20 s has only achieved logarithm 4 or in other words 99.99% removal, which is considered the weakest performance of continuous radiation. Also, in the discontinuous radiation mode, after 280 s time and 2 cm distance, the radiation performance towards the complete removal of bacteria is equal to the logarithm of 6 or 99.999%, which is equal to the amount of bacteria removal in continuous radiation.
Conclusion: The efficiency of pulsed radiation was greater as compared to continuous radiation.
Nahid Jalilian, Abdullah Sheykhi, Leila Mirzaei, Zeinab Gholami, Moayed Adiban,
Volume 16, Issue 2 (9-2023)
Abstract
Background and Objective: Butter is a known dairy product in the world and has an important role in human nutrition. Ignoring sanitary tips in this product leads to low quality of the product and outbreak. Therefore, this study aims to investigate bacterial pollution of local butter produced from cow and sheep milk in Ilam city.
Materials and Methods: In this analytical study, 150 samples of traditional cow and sheep butter were collected and studied for microbial contamination for 1 month from different production centers. SPSS version 23 software was used to analyze the collected data.
Results: From 75 samples of cow butter, 25.3% of the samples are polluted to S. aureus, 44% to S. epidermidis, 38.7% to Salmonella, 12% to Total coliform 10.7% to E. coli, and 12% do not have any pollution. From 75 samples of sheep local butter, 12% of the samples are polluted to S. aureus, 72% to S. epidermidis, 48% to Salmonella, 24% to Total coliform, and 17.3% to E. coli. A significant difference (P< 0.05) between pollution to S. aureus and S. epidermis in cow and sheep samples exists.
Conclusion: The results of this study showed that contamination of consumed local butter in Ilam city is considerably high; Therefore, it is important to pay attention to food hygiene in different stages from production to consumption.
