Bacteria In Media Research Articles

Isolation and identification of microbes associated with mobile phones in Dammam in eastern Saudi Arabia.

Objective:This study was conducted to determine microbial contamination of mobile phones in the city of Dammam, in the eastern region of Saudi Arabia, and identify the most important microbial species associated with these phones in order to take the necessary remedial measures.Materials and Methods:The analysis of a total of 202 samples was done to identify fungal and pathogenic bacteria isolates. Sterile swabs were firmly passed on the handset, the buttons and the screens of mobile phones, then inoculated into media of bacteria and fungi. Frequency distribution of isolates were calculated.Results:There were 737 isolated of the following bacteria: Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Neisseria sicca, Micrococcus luteus, Proteus mirabilis, Bacillus subtilis, and Enterobacter aerogenes at the rate of 56.58, 13.57, 8.01, 7.73, 6.51, 3.66, 2.85 and 1.09% respectively. There were fungal isolates as follows: Alternaria alternata, Aspergillus niger, Cladosporium sp., Penicillium spp., Aspergillus flavus, Aspergillus fumigatus, Rhizopus stolonifer, Aspergillus ochraceus at the rate of 29.07, 26.74, 20.93, 10.47, 6.98, 2.33, 2.33, 1.16%, respectively.Conclusions:The study showed that all mobile phones under consideration were infected by several microbes, most of which belonged to the natural flora of the human body as well as airborne fungi and soil. This means that it is necessary to sterilize hands after contact with a phone since it is a source of disease transmission.

Behavior of Pulsed Electric Fields Injured Escherichia coli O157:H7 Cells in Apple Juice Amended with Pyruvate and Catalase

Pulse Electric Field (PEF) treatment has been used to inactivate bacteria in liquid foods. However, information on the behavior of PEF injured Escherichia coli bacteria in media during storage at 5 and 23°C are limited. In this study, we investigated the fate of E. coli O157:H7 cells at 6.8 log CFU/ml in apple juice treated with PEF at 7.2 kV/cm and 32.2 kV/cm, 18.4 A with pulse width of 2.6 s at 25, 35, 45 and 55°C, at a fl ow rate of 120 ml/min. The juices collected were amended with pyruvate and catalase (0 to 0.1%) and then stored at 5 and 23°C for 24 h. Periodically (0, 3, 6, and 24 h), 0.1 ml of the treated sample was plated on Sorbitol MacConkey Agar (SMAC) and Tryptic Soy Agar (TSA) amended with catalase and pyruvate to determine percent injury, viability loss and behavior of injured cells. PEF voltage at 32.2 kV/cm and treatments at 35, 45 and 55°C led to signi fi cant decline in the surviving cell populations than treatment at 7.2 kV/ cm. The injured populations in control media were higher than media amended with pyruvate and catalase suggesting possible recovery of PEF injured E. coli cells.

150. IN VITRO CHARACTERISATION OF BIOFILM FORMATION IN HUMAN FOLLICULAR FLUID

Previous studies have detected bacteria in follicular fluid collected at the time of trans-vaginal oocyte retrieval but this was not shown to adversely affect ART outcomes. The antimicrobial properties of follicular fluid have also been investigated, and follicular fluid was reported to be inhibitory to Gram positive bacteria after four days, but supported the growth of Gram negative bacteria. In this study 36 follicular fluid specimens collected from assisted reproductive technology (ART) patients were tested for the presence of bacteria by culture and 16S rRNA PCR assays. Follicular fluid aliquots (24) were incubated and subcultured for 28 weeks and the ability of these follicular fluids to form biofilms in vitro was assessed. A further 12 follicular fluid specimens were inoculated into broth media with and without the addition of estradiol and progesterone at concentrations reported in follicular fluid of hyperstimulated women. Bacteria in polymicrobial (22%) or singles species populations (78%) were detected in the 24 follicular fluid specimens tested. The most prevalent bacteria detected were Lactobacillus species (18/35 total bacterial isolates, 51%) and Propionibacterium spp. (5/35, 14%). All follicular fluids supported the growth of bacteria in vitro for up to 28 weeks. Bacteria in 18/24 (75%) of follicular fluid specimens, formed biofilms in vitro. The majority of biofilms formed were grade IV 7/18 (39%) or grade III biofilms 7/18 (39%). Lactobacilli were also the most prevalent cultivable species within mature biofilms (51% of total isolates). Whilst high levels of steroid hormones were required for the growth of Bifidobacterium spp. in vitro, the growth of both Streptococcus agalactiae and Escherichia coli was inhibited by these hormones. Follicular fluid is not sterile and is an excellent growth media for bacteria, capable of supporting survival for long periods of time. Bacteria which can survive within follicular fluid over time can form mature biofilms, which enables persistence. Women undergoing ART cycles have elevated concentrations of steroid hormones within their follicular fluid and this can modulate the ability of some bacterial species to proliferate. The impact of these bacteria on the developing oocyte and ART pregnancy outcomes requires further investigation.

Apical negative pressure irrigation versus conventional irrigation plus triantibiotic intracanal dressing on root canal disinfection in dog teeth

The aim of this study was to compare in vivo the efficacy of 2 root canal disinfection techniques (apical negative pressure irrigation versus apical positive pressure irrigation plus triantibiotic intracanal dressing) in immature dog teeth with apical periodontitis. Two groups of root canals with pulp necrosis and apical periodontitis were evaluated according to the disinfection technique: group 1: apical negative pressure irrigation (EndoVac system); and group 2: apical positive pressure irrigation (conventional irrigation) plus triantibiotic intracanal dressing. The first sample (S1) was collected after lesions were radiographically visible, and the second sample (S2) was collected after apical negative pressure irrigation (group 1) or conventional irrigation/triantibiotic dressing (group 2). All samples were seeded in a culture medium for anaerobic bacteria. Colony-forming unit counts were analyzed statistically by the Mann-Whitney test (alpha = .05). Microorganisms were present in 100% of canals of both groups in S1. In S2, microorganisms were absent in 88.6% of group 1's canals and 78.28% of group 2's canals. There was no significant difference between the groups in either S1 (P = .0963) or S2 (P = .0566). There was significant (P < .05) bacterial reduction from S1 to S2 in both groups. In immature teeth with apical periodontitis, use of the EndoVac system can be considered to be a promising disinfection protocol, because it provided similar bacterial reduction to that of apical positive pressure irrigation (conventional irrigation) plus intracanal dressing with the triantibiotic paste, and the use of intracanal antibiotics might not be necessary.

Successive Ferric and Sulphate Reduction using Dissimilatory Bacterial Cultures

In the present work the kinetics of ferric reduction was investigated using dissimilatory ferric- and sulphate-reducing bacterial cultures. The effect of sulphate reduction on Fe(III) reduction was also studied. The study is an attempt to improve the biological reduction rate of Fe(III) as an alternative biotechnological way to the reduction step in steelmaking processing operations. The results obtained show that the reduction of ferric iron and sulphate took place in a successive way and none synergetic effect was detected. The simultaneous action of both metabolic activities did not enhance the process but slowed down the kinetics of ferric reduction. The reduction process of 3 g/L of soluble ferric and 3 g/L of sulphate lasted 25 days. Ferric iron was the first electron acceptor to be reduced in the first 15 days followed by the sulphate reduction in the following 10 days. That result suggests that ferric reduction is a preferential metabolic process over sulphate reduction when both electron acceptors coexist. None improvement in the kinetics was observed using an electron donor concentration in excess. In contrast, the total reduction of ferric ion (3 g/L) with adapted bacterial cultures was achieved in only 36 h. The presence of sulphate had no effect on the ferric reduction. Finally, an improved culture medium for ferric-reducing bacteria is also proposed.

ULTRASOUND SCAN

O b j e c t i v e : To assess the infective potential of ultrasound gel and probes when used in a routine manner on ambulatorypatients with intact skin. At our institute, ultrasound probes are wiped with a non-sterile absorbent paper towel after each patient. The probesbecome dry and clean in social terms but we were unsure if they also became bacteriologically decontaminated after wiping clean. We alsowished to ascertain the intrinsic infective potential of ultrasound gel. Materials a n d m e t h o d s : Bacteriological samples were taken from probesurface (after wiping it clean as per our protocol); gel dispensing bottles; and the gel jars that contain the gel in bulk. A total of 61 sampleswere cultured, out of these 13 were jar samples that were acquired daily on 13 days, 10 from gel bottles and 38 from probe surface (27before beginning ultrasound, 11 after ending the day's work). Probe surface samples were collected on sterile cotton wipes dipped in sterilenutrient broth; bottle and jar samples were collected by sterile nickel loops and cultured on commercially available nutrient agar. Colonieswere counted at 24 and 48 hours. R e s u l t s : The results show bacterial contamination in all (10/10) gel bottle samples, 7% pre-scan probesurface wipes (2/27) and 27.3% (3/11) on post scan wipes. Gel Jar samples were sterile on the first 3 days and then progressively showedgreater colony counts. This showed that the gel is initially sterile but is apparently contaminated from air and it serves as growth mediumfor bacteria. C o n c l u s i o n : We conclude that the highest contamination is observed in gel bottle samples (100%). The lowest contaminationwas observed from wiped probe samples. This was probably due to repeated cleaning of probes by the operators. Gel jar samples havethe second highest contamination but the initial samples showed no growth. The ultrasound gels probably contain no or little antibacterialagent and the gel serves as a growth medium for bacteria.

Improvement of color and physiological properties of tuna-processing by-product by gamma irradiation

Although the by-products from fishery industry had many nutrients, it is being wasted or only used as bacteria media. In this study, the effect of a gamma irradiation on the cooking drips of Thunnus thynnus (CDT) was investigated to examine the possible use of the cooking drips as a functional material for food and cosmetic composition. Total aerobic bacteria, and yeasts/molds from CDT were detected at the level of 2.79 and 2.58 Log CFU/mL, respectively. But, CDT was efficiently sterilized by a gamma irradiation at a low dose of 1 kGy. The Hunter L* value of the gamma-irradiated ethanol extract of CDT was increased, and the a* and b* values were decreased compared to the non-irradiated extract, showing color improvement. Antioxidant activity of the ethanol extract of CDT was increased by a gamma irradiation depending on the irradiation dose. The increased contents of polyphenolic compounds and proteins in CDT extract by gamma irradiation may be the reason of the increased biological activity. These results suggested that the wasted cooking drips can be successfully used as functional components with gamma irradiation treatment.

Nanocomposites of bacterial cellulose/hydroxyapatite for biomedical applications

In the present work, a nanocomposite material formed by bacterial cellulose (BC) networks and calcium-deficient hydroxyapatite (HAp) powders was synthesized and characterized. The HAp nanoparticles were previously prepared by a wet chemical precipitation method, starting from aqueous solutions of calcium nitrate and di-ammonium phosphate salts. Energy-dispersive spectroscopy reveals that the prepared HAp corresponds to calcium-deficient hydroxyapatite. BC-HAp nanocomposites were prepared by introducing carboxymethylcellulose (CMC) into the bacteria culture media. HAp nanoparticles were then introduced and remained suspended in the culture medium during the formation of cellulose nanofibrils. The maximum gel thickness was obtained after 21 days of bacteria cultivation. X-ray diffractograms showed the difference of crystallinity among the materials involved in the formation of nanocomposites. The inorganic and organic bonds that corresponded to hydroxyapatite and bacterial cellulose respectively, were depicted by attenuated total reflectance Fourier transform infrared spectra. Scanning electron microscopy and atomic force microscopy measurements confirmed the formation of networks and fibres with smaller diameter corresponding to BC synthesized in the presence of CMC. Image analysis was also used to assess the orientation distributions and Feret diameters for networks of BC and BC-CMC. Thermogravimetric analysis showed that the amount of the mineral phase is 23.7% of the total weight of the nanocomposite. Moreover, HEK cells were cultivated and the biocompatibility of the materials and the cell viability was demonstrated.

Bacterial inhibiting surfaces caused by the effects of silver release and/or electrical field

In this study, silver–palladium surfaces and silver-bearing stainless steels were designed and investigated focusing on electrochemical principles to form inhibiting effects on planktonic and/or biofilm bacteria in water systems. Silver-resistant Escherichia coli and silver-sensitive E. coli were used for the evaluation of inhibiting effects and the inhibiting mechanism. For silver–palladium surfaces combined with bacteria in media, the inhibiting effect was a result of electrochemical interactions and/or electrical field, and in some specific media, such as ammonium containing, undesired silver ions release can occur from their surfaces. For silver-bearing stainless steels, the inhibiting effect can only be explained by high local silver ions release, and can be limited or deactivated dependent on the specific environment.

Growth and metabolic features of lactic acid bacteria in media with hydrolysed fish viscera. An approach to bio-silage of fishing by-products

The reparameterization of two classic growth models (the logistic and Gompertz equations), and the dynamic modification of the integrated form of the first of these, was applied to the description of the kinetics and metabolic behaviour of six strains of lactic acid bacteria in four media: three of these from visceral waste from fishing products, and one commercial medium. The descriptions obtained –always consistent models and statistically significant parameters– provided a wide range of reliable numerical values on notable characteristics of microbial growth and bioproductions, which allowed the assessment of the individual systems by direct comparison, and also the suggesting of the potentially most suitable groups (of species of fish and of bacteria) for bio-silage processes.

Microbial-Corrosion Resistance of the Cu-Containing Ferrite Stainless Steels after Antibacterial Treatment

Microbial-corrosion resistance of Cu-containing ferrite stainless steels after antibacterial treatment in heterotrophic bacteria culture medium was investigated by means of various electrochemical techniques and microbial methods. The results showed that corrosion potential changed orderly along with metabolism of heterotrophic bacteria. Antibacterial treatment helped to enhance the stability of passive film and reduce the pitting sensibility when stainless steel was immersed in culture medium. Dispersion distributed epsilon-Cu phase on the surface of antibacterial stainless steel depressed activity of heterotrophic bacteria, thereafter alleviated the heterotrophic bacteria corrosion and improved the microbiological corrosion resistance of antibacterial stainless steel.

A Rapid Analytical Method for Free Choline by LC and Its Application for Bacterial Culture Medium Samples

A rapid, and inexpensive analytical method for free choline is described here. Choline was derivatized with benzoyl chloride and analyzed by HPLC with UV detection. Choline samples in the micro-molar range were determined with good repeatability. The precision (RSD) was not greater than 10%. The quantification limit was 10 μM (3σ), and the linear calibration range was between 10 and 1,500 μM. This method was applied to the measurement of free choline in a culture medium of bacteria and was shown to be suitable for aqueous samples with a wide concentration range and for routine analyses.

Poly(vinyl alcohol) Scaffolds with Tailored Morphologies for Drug Delivery and Controlled Release

AbstractPoly(vinyl alcohol) (PVA) scaffolds are prepared by a cryogenic process that consists of the unidirectional freezing of a PVA solution. The scaffolds exhibit a microchanneled structure, the morphology of which (in terms of pore diameter, surface area, and thickness of matter accumulated between adjacent microchannels) can be finely tailored by the averaged molecular weight of PVA, the PVA concentration in the solution, and the freezing rate of the PVA solution. The resulting PVA scaffolds are suitable substrates for drug‐delivery purposes, the drug release being controlled (from tens of minutes up to several days) by the morphology of the microchanneled structure. In vitro experiments reveal the efficiency of PVA scaffolds for controlling the release of ciprofloxacin into a bacteria culture medium.

Adipose tissue extract enhances skin wound healing

The main function of adipose tissue has been considered as storage of triglycerides. Adipose tissue was considered harmful for healing extensive and deep burns because of poor circulation and easy liquefaction in wound beds, which offer an excellent culture medium for bacteria. However, these traditional concepts have been challenged with the discovery of the endocrine function of adipose tissue. To investigate the effects of adipose tissue extract on wound healing, we created four 3.0 x 2.5 cm full-thickness wounds on each side of the back of male Wu Zhi Shan minipigs (n=6), for eight wounds in each animal. The wounds were randomly divided to receive normal saline (0.5 mL; controls), adipose tissue extract (1.5 g), basic fibroblast growth factor (50 U/cm(2)), and epidermal growth factor (50 U/cm(2)). Reduction in wound area and wound volume was accelerated with adipose tissue treatment as compared with growth factor or control treatment. The thickness of the regenerated epidermis and the number of new vascular nets were markedly increased in adipose tissue-treated wounds. Biopsy of adipose tissue-treated wounds showed enhanced expression of proliferation cell nuclear antigen (PCNA) and Factor VIII-related antigen, which indicated active cell differentiation and proliferation. In vitro study in rat tissue showed adipose tissue extracts stimulating skin growth. Bacteriology results showed no significant differences in amount or type of bacteria, whatever the treatment. These results may challenge the traditional concept that adipose tissue plays a negative role in wound healing and may offer direct evidence for encouraging the retention of adipose tissue in autologous skin grafting for skin wounds.

Hydrogel Scaffolds with Immobilized Bacteria for 3D Cultures

We have studied the suitability of a cryogenic process (e.g., ice-segregation-induced self-assembly, ISISA) for preparation of polyvinyl alcohol (PVA) scaffolds with in situ immobilized bacteria (e.g., Escherichia coli). Confocal fluorescence microscopy and impedance measurements were used to evaluate the extension of bacteria proliferation within the scaffold macrostructure. The bacteria efficiency for colonization of the scaffold macrostructure is compared for bacteria immobilized with and without the use of additional cryoprotectans. Cryoprotection by bacteria entrapment in alginate beads containing glucose results in a significant improvement (more than 2-fold as compared to non-cryoprotected) of bacteria proliferation within the PVA scaffold. Results are also compared with the most widely used method for cells colonization of scaffolds; i.e., soaking of a preformed PVA scaffold in bacteria culture medium.

A new B-PAn-P system for the detection of bacteria population

A new base-type polyaniline piezoelectric bacteria culture (B-PAn-P) system for rapid detection of bacteria population was proposed. In this system, interdigital electrode coated with a base-type polyaniline/poly vinyl alcohol (B-PAn/PVA) composite film was used as probe (B-PAn probe) in place of steel electrode in multi-channel series piezoelectric quartz crystal (MSPQC) system. The probe was directly connected to the piezoelectric detection system. B-PAn/PVA film can react with CO2 produced by the growth of bacteria in culture medium, which caused the film electrical properties change. This change can be sensitively monitored by piezoelectric detection system. The superiority of using proposed probe instead of steel electrode were: firstly, it was more sensitive to bacteria growth response and secondly, it did not require a specially formulated culture medium which was demanded in MSPQC system. Just like MSPQC, proposed system can be used to detect bacteria population. When used to quantitatively determine Pseudomonas aeruginosa, the frequency detection time (FDT) obtained in frequency shift curve had a linear relationship with the logarithm values of initial concentration of P. aeruginosa in the range of 10 to 106cfuml−1. The detection limit was 10cfuml−1. Compared with MSPQC system, proposed system was more sensitive and no special demand to culture medium.

Characterization of a New Thermophilic Spore Photoproduct Lyase from Geobacillus stearothermophilus (SplG) with Defined Lesion Containing DNA Substrates

The Geobacillus stearothermophilus splG gene encodes a thermophilic spore photoproduct lyase (SplG) that belongs to the family of radical S-adenosylmethionine (AdoMet) enzymes. The aerobically purified apo-SplG forms a homodimer, which contains one [4Fe-4S] cluster per monomer unit after reconstitution to the holoform. Formation of the [4Fe-4S] cluster was proven by quantification of the amount of iron and sulfur per homodimer and by UV and EPR spectroscopy. The UV spectrum features a characteristic absorbance at 420 nm typical for [4Fe-4S] clusters, and the EPR data were found to be identical to those of other proteins containing an [4Fe-4S]+ center. Probing of the activity of the holo-SplG with oligonucleotides containing one spore photoproduct lesion at a defined site proved that the enzyme is able to turn over substrate. In addition to repair, we observed cleavage of AdoMet to generate 5'-deoxyadenosine. In the presence of aza-AdoMet the SplG is completely inhibited, which provides direct support for the repair mechanism.

Detection of Staphyl ococcus aureus capsules producer isolated from bovine and buffaloes mastitis

This study was done for the detection of capsulated Staphylococcus aureus strains which were isolated from bovine & buffaloes Mastitis. 23 (57.5 %) & 8 (53 %) strains of these bacteria were isolated, 6 (26 %) & 2 (13.3 %) were capsule producing strains, and that 9 (39.1 %) & 4 (26.6 %) were slime producing strains, respectively. An increase in the number of capsules and slim producing strains was observed following growing of these bacteria in culture media containing glucose and milk. The experimentally performed histo-pathological study, revealed presence of capsules in lung sections stained with Hematoxylin–Eosin as a halo areas appeared around the bacterial cells. In addition to a strong positive reaction with periodic acid shiffs.

Development of a novel method based on liquid chromatography–evaporative light scattering detection for the direct determination of streptomycin and dihydrostreptomycin in raw materials, pharmaceutical formulations, culture media and plasma

A novel method for the non-derivatization liquid chromatographic determination of streptomycin (STR) and dihydrostreptomycin (DHSTR) was developed and validated based on evaporative light scattering detection (ELSD). Utilizing a ThermoHypersil BetaBasic C 18 analytical column, evaporation temperature of 50 °C and pressure of nebulizing gas (nitrogen) of 3.5 bar, the optimized mobile phase was 1.25 mL L −1 TFA aqueous solution, in an isocratic mode at a rate of 1.0 mL min −1. STR was eluted at 5.6 min and DHSTR at 7.8 min with a resolution of 4.4. Linear calibration curves were obtained from 2 to 120 μg mL −1 ( r > 0.9990) for STR and 2–75 μg mL −1 ( r > 0.9994) for DHSTR, with a LOD equal to 0.7 and 0.5 μg mL −1, respectively. The developed method was applied for the assay of STR and DHSTR (sulfate) in pharmaceutical raw materials and formulations, while the simultaneous direct determination of sulfate was feasible ( t R = 2.5 min, LOD = 1.4 μg mL −1, double logarithmic calibration curve in the range of 4–50 μg mL −1, r > 0.9998). Modified isocratic mobile phase (H 2O–ACN, 90:10, v/v, containing 1.25 mL L −1 TFA), was used for the determination of streptomycin B impurity in STR sulfate raw material and a gradient mobile phase (H 2O–ACN containing TFA) was used for the determination of DHSTR in the presence of penicillinG procaine. The developed method was also applied for the assay of commercial formulations (STR powder and DHSTR injection solution and suspension) (%recovery 98–102, %RSD < 1.3, n = 3 × 3), for the determination of STR in bacteria culture medium (%recovery 99.6, %RSD = 0.8, n = 3 × 3), and for the determination of DHSTR in human plasma (2.0–23.0 μg mL −1) after solid phase extraction using carboxylate cartridges (%recovery 98.4–101.8, %RSD = 3.2, n = 3 × 3).

Inhibition of Epsilon-Poly- l -Lysine Biosynthesis in Streptomycetaceae Bacteria by Short-Chain Polyols

Antimicrobial epsilon-poly-L-lysine (ePL) is secreted by Streptomycetaceae bacteria, and the mechanism of ePL biosynthesis remains to be elucidated. We previously reported that an unknown ePL derivative accumulates in the culture medium of ePL-producing bacteria when glycerol is added to the culture medium (Nishikawa and Ogawa, Appl. Environ. Microbiol. 68:3575-3581, 2002). In this study, by using matrix-assisted laser desorption ionization-time of flight mass spectrometry and nuclear magnetic resonance, we identified the unknown derivative as the ester formed between the hydroxyl group of a glycerol molecule and the terminal carboxyl group of an ePL molecule. When a short-chain aliphatic polyol, such as ethylene glycol, propanediol, or butanediol, was added instead of glycerol, a corresponding ePL-polyol monoester accumulated in the culture medium of ePL-producing bacteria. ePL esterification was accompanied by ePL synthesis in intact cells and a cell-free system, but no esterification of exogenous ePL was observed. ePL-polyol esters were formed during lysine polymerization. The number of lysine residues of ePL-polyol esters decreased with increasing polyol concentration. Taken together, these results indicate that ePL synthesis is inhibited by polyols via esterification and that ePL elongation occurs via the incorporation of lysine monomers into the carboxyl terminus of ePL.