Concentration Of Pathogenic Bacteria Research Articles

畜禽舍空间相控分裂导线复合除尘杀菌装置设计研究

Livestock scale breeding is the inevitable trend of future livestock and poultry husbandry. Closed breeding requires excellent environment and livestock and poultry housings contain a lot of dust, pathogenic microorganisms and harmful gases, affecting the health of livestock and poultry and breeding personnel. Most of the common sterilization and dust collection devices for livestock and poultry housings on the market are too high energy consumption, and easy to cause secondary pollution. Therefore, an environmental purification device was designed to absorb dust in the air and kill harmful bacteria by using high voltage pulsed electric field. The device was designed using phase control principle and bundled conductor. COMSOL Multiphysics software was used to simulate the layout of single conductor, twin bundled conductor and quad bundled conductor. It was found that when the conductor was designed as twin bundled conductor or quad bundled conductor, the gradient distribution of spatial electric field intensity was more uniform and the downward trend of electric field was slower, which could effectively improve the dust collection and sterilization efficiency of the device. At the same time, a variety of electric field environments can be set up by using phase difference to meet different environmental requirements of livestock and poultry. The compound dust collection and sterilization device with phase-controlled bundled conductor for livestock and poultry housing space includes high voltage pulse generator, bundled conductor, high voltage special timer, insulator and other parts, which can effectively reduce the dust content in the air, the concentration of pathogenic bacteria, harmful gases, etc. after assembly test and can also reduce the humidity in the livestock and poultry housings.

Probiotic-Free Microfiber Membrane for Promoting Infected Wound Healing by Regulating Wound Flora Balance

Anti-infection properties are critical for promoting wound healing. Probiotic therapy displays great advantages to combat infection by regulating the wound flora balance, compared with biocidal-based wound dressing. However, probiotic therapy has large obstacle and potential biosafety risks for proper application. Herein, a probiotic-free wound dressing for accelerating wound healing is reported to regulate wound flora balance without inoculating microorganisms at the wound. A poly(4-methyl-1-pentene) (PMP) microfiber membrane exhibits strong bacterial adhesion (1.74 × 109 CFU/cm2), and bacterial adhesion count correlates with the surface energy and fiber diameter of PMP microfiber membranes. The efficient bacterial adhesion of the PMP microfiber membrane endows the ability to regulate wound flora for accelerating the healing. Pathogenic bacteria could be removed from the infectious wound through dressing change, so the concentration of pathogenic bacteria at the wound could be kept at a low level, which is beneficial to wound healing. Based on the rat model, wounds have the lowest bacterial concentration and a fast healing rate after treatment with a PMP microfiber membrane, compared with the group treated with commercial dressings. These results reveal that the PMP microfiber membrane could be used to accelerate infectious wound healing by regulating wound flora balance. The work provides a new idea for developing novel antibacterial dressings without any side effects.

Estimation and Impact Factor of Pathogens in the Lijiang River Using Water Quality Modeling

The pathogen plays an important role in spreading infection and bad impact on the public health of the river. Therefore, water quality as a model is used to simulate the spreading and fate of the pathogen in Lijiang River, it is located in Lijiang City, Yunnan Province, China (100°25'E, 26°86'N). Even at low bacterial levels, there is a risk of pathogens in the Lijiang River ecosystem. The water quality model results showed that the spatiotemporal (space and time) migration of pathogenic bacteria in Lijiang River from 2005 to 2015 was quantitatively revealed by the model simulation. The simulation results also showed that the transports of pathogenic bacteria in Lijiang River are extremely sensitive to the speed distribution and seasonal temperature characteristics. The study found that the rising water temperature in spring leads to a sharp rise in the concentration of pathogenic bacteria. When the water temperature is low in winter, the simulated pathogenic bacteria are relatively stable, which is lower than the concentration of pathogenic bacteria at high temperature. If the spring water temperature rises, the flow rate increases, the concentration of pathogenic bacteria accordingly increases. This research recommends the development of best management practices to control microbial growth in river basins.

Вивчення біотопу пологових шляхів у вагітних з маловоддям

The article focuses on clinical-statistical analyses of microbiocenosis of maternity pathways of women with oligohydramnios, which will enable the usage of etiotropic mediator aimed at reducing of the frequency of fetus and newborn’s infecting. The objective: to learn the biotope of vaginal environment in the process of pregnancy complicated by oligohydramnios. Materials and methods. There were observed 120 pregnant women with oligohydramnios at gestation term of 27–29 weeks (the main group). 30 women with physiological pregnancy process constituted the control group. Oligohydramnios was diagnosed on the basis of complex examination of pregnant women at the term of 27–29 weeks with the help of standard determination of amniotic fluid index. All the women underwent bacterioscopic and bacteriological examination and detection of antigens to: chlamydia, ureaplasma, mycoplasma, virus of genital herpes, cytomegalic virus. Results. In the main group of women there was diagnosed ureaplasmosis, Gardnerella vaginalis, chlamydiosis, trichomoniasis, Candida albicans, more than half of women had increased concentration of pathogenic bacteria (staphylococcus epidermidis, aureus, saprophyticus, enteric bacteria, enterococcus faecalis), genital herpes, cytomegalovirus. Most of the representatives of the main group had bacterial infection of genital tract (69.17%), and complex bacterial-viruses infection (30.83%). Conclusion. Results of the research show that pregnant women with urogenital infections, inflammations of pelvic organs complicated by obstetrical – gynecological anamnesis should be referred to the group of high risk in reference to the development of oligohydramnios. Key words: pregnancy, microbiocenosis of vulva, oligohydramnios, infections.

An automated system for separation and concentration of food-borne pathogens using immunomagnetic separation

In this study, we report an approach for the automated separation and concentration of pathogenic bacteria from food samples as a pretreatment step before detection. We developed an automated immunomagnetic separation (IMS) system, which included pre-enrichment of food samples, incubation with immunomagnetic beads, and separation and concentration of immunomagnetic beads along with bound target bacteria using an automated instrument based on IMS technology. Magnetic recovery bars covered with glass cylinders were utilized for separation of magnetic beads in food samples introduced into collection tubes. The separated magnetic beads with bound bacteria were dispersed in 1 mL phosphate-buffered saline (PBS) in concentration tubes. The efficiency of separation and concentration of the target pathogenic bacteria by the fabricated system were determined using plate counting with E. coli O157:H7 and whole milk as the model target bacteria and real food matrix, respectively. To achieve high concentration and recovery yield, the spiked milk samples were enriched with buffered peptone water before incubation with immunomagnetic beads and introduction into the collection tubes. The entire procedure from pre-enrichment through to concentration was completed within 2 h with the automated IMS system. The proposed approach achieved over 100-fold concentration of inoculated E. coli O157:H7 from milk samples with over 20% recovery of viable cells after pre-enrichment. These results illustrated the feasibility of the developed auto-IMS platform for rapid inspection of food pathogens.

Biological preparation of highly effective immunomagnetic beads for the separation, concentration, and detection of pathogenic bacteria in milk

We introduce a system for the efficient separation and concentration of pathogenic bacteria using biologically prepared immunomagnetic beads. Amylose magnetic beads (AMBs) were synthesized by an enzymatic reaction of amylosucrase from Deinococcus geothermalis (DGAS). The simple and rapid conjugation of AMBs and antibodies was achieved by the MBP-SPG fusion protein. MBP (maltose binding protein) binds to the surface of an AMB owing to its intrinsic affinity to the di-glucose in the AMB. SPG (streptococcal protein G) fused to the MBP has specific affinity to the Fc region of the antibody. Anti-Escherichia coli O157 antibodies were conjugated to the AMBs through a MBP-SPG linker without any physical and chemical treatments. The efficiency of separation and concentration of the target E. coli O157:H7 by the functionalized AMBs was revealed by plating counting, conventional polymerase chain reaction (PCR), and real-time RCR analysis. The immuno-AMBs effectively separated and concentrated the target bacteria from a commercial milk sample spiked with known number of bacteria, which was then analyzed by PCR to a detection limit of 10CFU/mL. On the other hand, no PCR product was produced when milk was introduced directly to a PCR reaction. These results show that MBP-SPG is an effective linker and the resulting immuno-AMBs are capable of separating and concentrating the target bacteria from a food matrix.

Effect of Post-treatment Conditions on the Inactivation Rate of Pathogenic Bacteria after the Composting Process

ABSTRACTA urine diverting composting toilet system is modified for rural areas of Burkina Faso from the system that is commercially available in Japan. The rural model does not have a heat source. It still has some pathogens in the compost after three months of operation and hence requires a post-treatment. In this study, the kinetics inactivation of Enterococcus and Escherichia coli, selected as an indicator for pathogenic bacteria, was determined during post-treatment at different temperatures (37, 50, and 70°C) with varying moisture contents (50, 60, and 70%). Additionally, the fate of pathogenic bacteria under different lime doses (1.0, 0.5, and 0.1 g) at 60% of moisture content were determined. As a result, bacteria decreased as temperature increased, moisture reduced, and the length of time increased. However, under high temperature the effect of moisture was not significant. With regards to relative resistance of bacteria, Enterococcus was the most resistant to temperature. For 6 log reduction target to reduce the concentration of E. coli in compost, post-treatment conditions of 50°C, 50%, and a contact time over 4.5 h are needed or post-treatment conditions of 70°C, 50%, with a contact time of over 20 min are required. For Enterococcus, to achieve a 6 log reduction, post-treatment conditions of 50°C, 50%, with a contact time of 15 h or 70°C, 50%, with a contact time of over 2.5 h are required. The addition of the higher dose of Ca(OH)2 to increase the pH of compost to ≥8.1 was capable of reducing the concentration of pathogenic bacteria.

Pathogenic Bacteria in Finnish Bulk Tank Milk

While the quality of raw cow milk in Finland is known for its high hygienic standard, with the national average total bacterial count being below 10(4) CFU/mL annually, the prevalence of pathogenic bacteria in Finnish raw milk is underreported. The aim of this study was to determine the occurrence of Listeria monocytogenes, thermophilic Campylobacter spp., Salmonella spp., stx-positive Escherichia coli (STEC), coagulase-positive staphylococci, Yersinia spp., and Bacillus cereus group in raw cow milk samples collected from bulk tanks at 183 Finnish farms. Additionally, the hygienic quality of the milk was studied by determining the total bacterial and E. coli counts. L. monocytogenes was detected in 5.5% of the milk samples, with concentrations varying from <1 to 30 CFU/mL. Thermophilic Campylobacter spp. or Salmonella spp. were not detected in any of the samples. STEC with Shiga toxin-encoding stx2 was detected in 2.7% of the samples. Yersinia enterocolitica was detected in 7.7% of the samples; however, all isolates were negative for ail, suggesting that they were non-pathogenic. Coagulase-positive staphylococci were detected in 34.4% of the samples, with an average concentration of 25 CFU/mL in the positive samples. Members of the B. cereus group were detected in 20.8% of the samples, with an average concentration of 1 CFU/mL in the positive samples. No relationship was detected between E. coli or the total bacterial count and the presence of pathogenic bacteria, which suggests that pathogens can be present also in farms with excellent production hygiene. Although the concentration of pathogenic bacteria in fresh raw milk was mainly relatively low, it should be borne in mind that some of the pathogenic bacteria can survive and multiply at refrigeration temperatures and may cause a disease with a very low infectious dose. Thus, consumption of raw milk and related products poses a potential risk for food poisoning.