Colony-forming Units Of Bacteria Research Articles

LL-37_Renalexin hybrid peptide exhibits antimicrobial activity at lower MICs than its counterpart single peptides

An alarming global public health and economic peril has been the emergence of antibiotic resistance resulting from clinically relevant bacteria pathogens, including Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumonia, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species constantly exhibiting intrinsic and extrinsic resistance mechanisms against last-resort antibiotics like gentamycin, ciprofloxacin, tetracycline, colistin, and standard ampicillin prescription in clinical practices. The discovery and applications of antimicrobial peptides (AMPs) with antibacterial properties have been considered and proven as alternative antimicrobial agents to antibiotics. In this study, we have designed, produced, and purified a recombinant novel multifunctional hybrid antimicrobial peptide LL-37_Renalexin for the first time via the application of newly designed flexible GS peptide linker coupled with the use of our previously characterized small metal-binding proteins SmbP and CusF3H+ as carrier proteins that allow for an enhanced bacterial expression, using BL21(DE3) and SHuffle T7(DE3) Escherichia coli strains, and purification of the hybrid peptide via immobilized metal affinity chromatography. The purified tag-free LL-37_Renalexin hybrid peptide exhibited above 85% reduction in bacteria colony-forming units and broad-spectrum antimicrobial effects against Staphylococcus aureus, Escherichia coli, Methicillin-resistant Staphylococcus aureus (MRSA), and Klebsiella pneumoniae bacteria clinical isolates at a lower minimum inhibition concentration level (10–33 μM) as compared to its counterpart single-AMPs LL-37 and Renalexin (50–100 μM).Key points• The hybrid antimicrobial peptide LL-37_Renalexin has been designed using a GS linker.• The peptide was expressed with the carrier proteins SmbP and CusF3H+.• The hybrid peptide shows antibacterial potency against clinical bacterial isolates.

Analysis of aerosol generation during Er:YAG laser-assisted caries treatment: A randomized clinical trial.

Maintaining biosafety in dental practice involves the effective elimination of aerosols produced during dental treatment. To assess the quantity of aerosols and aerobic bacteria in the air during the treatment of caries. The study involved 60 patients with a total of 60 molar teeth (n = 60) in the mandible who were divided into 2 groups based on caries treatment method. Group 1 (G1, n = 30) received treatment with a conventional dental turbine (W&H Synea TA-98LC; W&H, Burmoos, Austria), while group 2 (G2, n = 30) underwent treatment with an Er:YAG (erbium-doped yttrium aluminium garnet) laser (LightWalker, Fotona, Slovenia). Measurements of aerosol particles between 0.3 Ęm and 10.0 Ęm near the operatorfs mouth were taken using the PC200 laser particle counter (Trotec GmbH, Schwerin, Germany). The number of aerobic bacteria in the air was determined using 60 Petri plates with a microbiological medium (Columbia agar with 5% sheep blood) and the sedimentation method. A control group (G3) was established to measure initial aerosol levels and initial total number of bacteria colony-forming units (CFUs) before each treatment. In G1 (dental turbine), the median value of aerosol particles was 57,021 (42,564.67,568), while in G2 (Er:YAG laser), it was significantly lower at 33,318 (28,463.35,484) (p < 0.001). The median total bacteria count per cubic meter of air in G1 (conventional dental turbine + high volume evacuator (HVE)), G2 (Er:YAG laser + HVE) and G3 (control group before caries treatment) were 734 (420.988), 158 (96.288) and 48 (32.74), respectively, with a statistically significant difference between the groups (p < 0.001). The use of Er:YAG laser during caries treatment resulted in a 41.6% reduction in aerosol amounts and a 78.5% decrease in the total bacterial count (TBC) compared to treatment with a dental turbine.

Calculating the limit of detection for a dilution series

AimsMicrobial samples are often serially diluted to estimate the number of microbes in a sample, whether as colony-forming units of bacteria or algae, plaque forming units of viruses, or cells under a microscope. There are at least three possible definitions for the limit of detection (LOD) for dilution series counts in microbiology. The statistical definition that we explore is that the LOD is the number of microbes in a sample that can be detected with high probability (commonly 0.95). Methods and resultsOur approach extends results from the field of chemistry using the negative binomial distribution that overcomes the simplistic assumption that counts are Poisson. The LOD is a function of statistical power (one minus the rate of false negatives), the amount of overdispersion compared to Poisson counts, the lowest countable dilution, the volume plated, and the number of independent samples. We illustrate our methods using a data set from Pseudomonas aeruginosa biofilms. ConclusionsThe techniques presented here can be applied to determine the LOD for any counting process in any field of science whenever only zero counts are observed. Significance and impact of studyWe define the LOD when counting microbes from dilution experiments. The practical and accessible calculation of the LOD will allow for a more confident accounting of how many microbes can be detected in a sample.

Imaging Diverse Pathogenic Bacteria InVivo with 18F-Fluoromannitol PET.

Infectious disease remains the main cause of morbidity and mortality throughout the world. Of growing concern is the rising incidence of multidrug-resistant bacteria, derived from various selection pressures. Many of these bacterial infections are hospital-acquired and have prompted the Centers for Disease Control and Prevention in 2019 to reclassify several pathogens as urgent threats, its most perilous assignment. Consequently, there is an urgent need to improve the clinical management of bacterial infection via new methods to specifically identify bacteria and monitor antibiotic efficacy invivo. In this work, we developed a novel radiopharmaceutical, 2-18F-fluoro-2-deoxy-mannitol (18F-fluoromannitol), which we found to specifically accumulate in both gram-positive and gram-negative bacteria but not in mammalian cells invitro or invivo. Methods: Clinical isolates of bacteria were serially obtained from wounds of combat service members for all invitro and invivo studies. Bacterial infection was quantified invivo using PET/CT, and infected tissue was excised to confirm radioactivity counts ex vivo. We used these same tissues to confirm the presence of bacteria by extracting and correlating radioactive counts with colony-forming units of bacteria. Results: 18F-fluoromannitol was able to differentiate sterile inflammation from Staphylococcus aureus and Escherichia coli infections invivo in a murine myositis model using PET imaging. Our study was extended to a laceration wound model infected with Acinetobacter baumannii, an important pathogen in the nosocomial and battlefield setting. 18F-fluoromannitol PET rapidly and specifically detected infections caused by A. baumannii and several other important pathogens (Enterococcus faecium, S. aureus, Klebsiella pneumoniae, A. baumannii, Pseudomonas aeruginosa, and Enterobacter spp.). Importantly, 18F-fluoromannitol PET was able to monitor the therapeutic efficacy of vancomycin against S. aureus invivo. Conclusion: The ease of production of 18F-fluoromannitol is anticipated to facilitate wide radiopharmaceutical dissemination. Furthermore, the broad sensitivity of 18F-fluoromannitol for bacterial infection invivo suggests that it is an ideal imaging agent for clinical translation to detect and monitor infections and warrants further studies in the clinical setting.

Evaluation of the Results of a Periodic Environmental Biosecurity Assessment Program on Air Quality in Controlled Environment Rooms of Hospitals.

Determine the utility of the Periodic Environmental Biosecurity Assessment Program (PEBAP) in achieving clean air as measured by the number of colony-forming units (CFU) of fungi and bacteria in the air. There is no international consensus on the sampling frequency, the recommended limits for microorganisms in the air nor on the usefulness of routine microbiological air monitoring of hospitals. During the PEBAP, data were recollected between 2010 and 2017 in eight hospitals in southeast Spain. Air samples were collected in very high risk rooms (VHRRs) and high risk rooms (HRRs), unoccupied, using active sampling methods. Temperature, relative humidity, air changes per hour (ACH), and differential pressure were measured. When limits of CFU of opportunistic fungi and bacteria established in the PEBAP were exceeded, corrective measures were adopted. We found a reduction (p < .01) of percentage of air samples with fungi growth throughout the years of PEBAP in all rooms. Aspergillus was the most frequent opportunistic fungus. We found a high compliance of the standards of CFU of bacteria in HRR, and the percentage of compliance in VHRR was lower than in HRR in all years. Differences in environmental and design parameters were statistically significant (p < .05) between rooms, except for ACH. PEBAP resulted in a useful tool to maintain and improve air quality in hospitals. The control of environmental biosecurity requires a multidisciplinary approach from preventive medicine, engineering, and cleaning services. Aspergillus is the most frequent opportunistic fungus in southeast Spain.

Responses of Okra and Soil Microbial Population Changes to the Application of Tithonia Manure &amp;nbsp;

Yield reduction in okra production is mostly associated with cultivation of marginal lands or continuous land cultivation. Hence, the need for sustainable approach to resuscitating soil fertility through Tithonia diversifolia manure application may alter microbial population. Two soil depths [Topsoil (0-15 cm) and Subsoil (15-30 cm)], three levels of Tithonia manure applications (control, half recommended and recommended at 120 kg N/ha) and three okras varieties (Clemson spineless, LD88 and NHAe 47-4) were evaluated in completely randomized design replicated thrice. Soil bacterial and fungal colonies were higher in the topsoil compared to the subsoil and increased with increase in level of tithonia manure application under topsoil, while the inverse was observed under subsoil condition for bacteria colony-forming units and mycorrhizal spore count. Under topsoil, LD88 variety treated with recommended rate of tithonia manure had the highest biomass dry matter (79.4 g). Significantly higher leaf area (395.92 mm2) and biomass dry matter (66.89 g) were produced by NHAe 47-4 and Clemson spineless treated with recommended rate of tithonia manure compared to their respective controls (181.37 mm2and 29.63 g) under subsoil. Varieties LD88 and Clemson spineless combined with recommended rates of tithonia manure were suggested for topsoil and subsoil conditions, respectively.

Toxicity of ZnO and Fe2O3 nano-agro-chemicals to soil microbial activities, nitrogen utilization, and associated human health risks

BackgroundVarious nano-enabled agrochemicals are being extensively used for soil remediation and to boost crop production by increasing the nutrient efficiency of fertilizers. However, understanding of their potential risks on the manure–soil–plant continuum is limited. These nano-agrochemicals can be potentially toxic to soil microbes and their associated functions, such as nitrogen (N) mineralization and decomposition of organic materials. Moreover, the accumulation of nanoparticles (NPs) in edible crops may reduce food quality, and can cause serious threats to human health. Accordingly, here we investigated how zinc (ZONPs) and iron oxide (IONPs) nanoparticles affect the soil microbial communities, their efficiency of decomposition and N mineralization, radish yield, and plant N recovery after soil application of poultry manure (PM). Furthermore, we studied the associated health risks (DIM, HRI) via dietary intake of radish.ResultsSoil application of ZONPs and IONPs significantly (P < 0.05) increased microbial biomass Zn/Fe indicating their microbial utilization. This decreased the colony-forming units (CFU) of bacteria and fungi. For example, the application of PM with ZONPs and IONPs decreased the CFU of bacteria by 32% and 19%, respectively. In case of fungi, the CFU reductions were slightly different (ZONPs: 28% and IONPs: 23%). Consequently, the N mineralization significantly decreased by 62% and 29% due to ZONPs and IONPs, respectively. Which ultimately resulted in the reduction of radish dry matter yield by 22% and 12%. The respective reductions of the apparent N recovery (ANR) were 65% and 39%. Health risk assessment indicated that DIM and HRI values from both the NPs lie under safe limits.ConclusionsWe conclude that both metal oxide nanoparticles (i.e., ZONPs and IONPs) can significantly affect the soil microbial community, their associated functions, and crop yield with the former being relatively more toxic. However, no evidence was found regarding the health risks to humans via dietary radish intake. These toxicological effects imply restricting the widespread production and use of NPs, and developing strategies for their safe disposal to avoid their contact with soil beneficial microorganisms.

Vitamin K5 Is an Efficient Photosensitizer for Ultraviolet a Light Inactivation of Bacteria

Photodynamic inactivation of bacteria has been proven as an effective method to inactivate pathogenic bacteria. This study identified vitamin K5 (VK5) as an efficient photosensitizer for ultraviolet light A (UVA) induced bacterial inactivation.Six species of bacteria, including Bacillus cereus (vegetative form), Escherichia coli , Pseudomonas aeruginosa, Staphylococcus aureus , Staphylococcus epidermidis , Klebsiella pneumoniae , and two species of antibiotic-resistant bacteria, Pseudomonas aeruginosa and Staphylococcus aureus, were grown and mixed with VK5 and irradiated with UVA in phosphate buffered saline (PBS) in 6-well plates following our previous procedures (Xu & Vostal, 2014). A representative figure of bacterial reduction of VK5 and UVA irradiation treated E. coli , as determined by a colony forming unit (CFU) count, is shown in Figure 1. Increasing concentrations of VK5 from 0 to 1600 µmol l-1 with fixed UVA irradiation doses produce a concentration-depended reduction of bacteria. Similarly, a UVA dose response for bacterial reduction is evident with fixed VK5 concentrations. As shown in Table 1, UVA irradiation (5.8 J cm-2) with vitamin K5 (1600 µmol l-1) reduced the CFU of bacteria by three to seven logs. Antibiotic resistant bacteria (Pseudomonas A. and Staphylococcus A ) did not exhibit resistance to the bactericidal effects of UVA and vitamin K5 combination treatment.Efficacy of VK5 and UVA for bacterial reduction was also evident in plasma although higher concentrations of VK5 and UVA doses were required. VK5 (500 or 2000 µ mol l-1 ) in 35% or 50% bacteria spiked plasma diluted with Platelet Additive Solutions was exposed to UVA irradiation at 6 and 30 J cm-2. This treatment reduced Escherichia coli and Staphylococcus aureus CFU by up to seven logs as shown in Figures 2a and 2b, respectively.Reactive oxygen species, hydroxyl radicals (˙OH) and superoxide anion radicals (O2˙−), were found generated in vitamin K5 aqueous solution after UVA irradiation, suggesting these oxygen species may mediate the inactivation of the bacteria. The O2˙−was generated in UVA-irradiated-VK5 PBS solution. At a fixed UVA dose of 2.9 J cm-2, the generation of O2˙− coincided with an increase in VK5 concentration from 0 to 1000 µ mol l-1 (Figure 3a). The generation of O2˙− was further confirmed by carrying out quenching study with superoxide dismutase (SOD) as specific quenchers. The production of O2˙− was reduced as the SOD concentration was increased from 0 to 640 units ml-1 in a 500 µ mol l-1 VK5 solution irradiated with a UVA (2.9 J cm-2 ) (Figure 3b). VK5 and UVA light combination also caused the release of ˙OH as the VK5 concentrations increased from 0 to 1000 µ mol l-1 with a fixed UVA dose of 2.9 J cm-2 The generation of ˙OH was further confirmed by mannitol, a specific quencher for ˙OH. Less ˙OH was produced when mannitol concentration was increased from 0 to 1 mol l-1, in the presence of a fixed VK5 concentration of 500 µ mol l-1 and a UVA dose of 2.9 J cm-2.Vitamin K5 and UVA light treatment is an effective method for reduction of bacteria in solutions including plasma and may be an effective way to reduce transfusion transmitted septic reactions from contaminated plasma products. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Method for Removing Thawed Human Milk From a Plastic Storage Bag Impacts Fat Retention.

Determine how thaw stage and bag manipulation (folding and squeezing) influence the retention of fat and number of aerobic bacteria colony-forming units when decanting human milk (HM) from plastic storage bags. Lactating women (n = 40) in the Greensboro, North Carolina area were recruited to provide fresh HM. Samples were equally divided and frozen in storage bags for 2 months. Two thaw stages (ice/liquid) and the use of bag manipulation (yes/no) were assessed. Fat was measured using ether extraction and bacteria were measured using plate enumeration. Paired t tests were used to compare the effects of thaw stage and bag manipulation on post-thaw fat content. Repeated measures analysis of variance was used to compare the effect of bag manipulation on pre- and post-thaw bacteria. Fat retention was not significantly different when thawing to liquid versus ice (mean difference = 0.10 g/dL; n = 17 paired samples; P = 0.07). Decanting with bag manipulation retained more fat than decanting without manipulation, but only when HM was thawed to liquid (mean difference = 0.13 g/dL; n = 11 paired samples; P = 0.005), not when HM was thawed to ice (P = 0.47). Bag manipulation did not increase total aerobic bacteria for either thaw stage (P = 0.49). Fat retention is influenced by the method of removing previously frozen HM from plastic storage bags. Folding and squeezing the storage bag when decanting HM thawed to a liquid state increases fat recovery without increasing bacterial contamination.

Biocompatibilidad con la superficie ocular y actividad antimicrobiana de una nueva solución multipropósito para lentes de contacto

Introducción: las soluciones multipropósito (SMP) para lentes de contacto blandos (LCB) desempeñan un papel esencial en la inhibición de agentes patógenos. Su efectividad antimicrobiana se evalúa in vitro, y su seguridad, in vivo, con ensayos clínicos que incluyen una combinación de diferentes soluciones y materiales para lentes. El objetivo es evaluar la biocompatibilidad de una nueva SMP producida en Colombia que contiene polihexametileno biguanida (PHMB) y determinar su actividad antimicrobiana. Materiales y métodos: estudio cruzado con 25 sujetos no usuarios de lentes, que fueron adaptados con cinco combinaciones diferentes de materiales de LCB con una nueva solución salina fisiológica de control (CS). El grosor corneal, la hiperemia conjuntival, la tinción corneal y la comodidad se evaluaron después de dos horas de uso del LC. La efectividad antimicrobiana se midió utilizando ensayos estándar ISO 14729. Resultados: solo hubo una diferencia significativa entre la nueva SMP y el CS para el Comfilcon A (p &lt; 0.05). Tampoco hubo diferencias significativas para el grosor o la tinción corneal, entre la combinación del material del lente y la nueva SMP con el CS (p &gt; 0.05). Después de dos horas de uso del lente, las puntuaciones de confort fueron superiores a 7.8. La SMP redujo las unidades formadoras de colonias (UFC) de bacterias en más de 3 log, y las UFC fúngicas en más de 1.0 log. Conclusiones: la nueva SMP cumplió con los estándares antimicrobianos de ISO 14729, y se considera segura y biocompatible con la superficie ocular, con altos niveles de confort.

Unraveling the toxic effects of iron oxide nanoparticles on nitrogen cycling through manure-soil-plant continuum

Soil contamination with metallic nanoparticles is increasing due to their increased use in industrial and domestic settings. These nanoparticles are potentially toxic to soil microbes and may affect their associated functions and thereby the nutrient cycling in agro-ecosystems. This study examined the effects of iron oxides nanoparticles (IONPs) on carbon (C) and nitrogen (N) dynamics of poultry (PM) and farmyard manure (FYM) in the soil. The application of IONPs increased iron content in soil microbial biomass, which reflected its consumption by the microbes. As a result, colony-forming units of bacteria and fungi reduced considerably. Such observations lead to a decrease in CO2 emission from PM and FYM by 27 and 28%, respectively. The respective decrease fractions in the case of N mineralization were 24 and 35%. Consequently, soil mineral N content was reduced by 16% from PM and 12% from FYM as compared to their sole application without IONPs. Spinach dry matter yield and apparent N recovery were increased by the use of organic waste (FYM, PM). The use of IONPs significantly reduced the plant N recovery fraction by 26 and 24% (P < 0.05) from PM and FYM, respectively. All the results mentioned above lead us to conclude that IONPs are toxic to soil microbes and affect their function i.e., carbon and N mineralization of applied manure, and thereby the on-farm N cycling from the manure-soil-plant continuum.

On the dose of plasma medicine: Equivalent total oxidation potential (ETOP)

This paper provides a new insight into the fundamentals of plasma medicine: The definition of “plasma dose.” Based on the dominant role of reactive oxygen nitrogen species (RONS) in plasma biological effects, we first propose the equivalent total oxidation potential (ETOP) as the definition of plasma dose. The ETOP includes three parts: the item H, which is the ETOP of the RONS generated by plasma; the item T, which is associated with the reactive agents unrelated to RONS, such as UV/vacuum ultraviolet (VUV) emission of plasma; and the item f(H,T), which is related to the synergistic effects between H and T factors. To evaluate the feasibility of the ETOP as a plasma dose, the bacterial reduction factor (BRF), which is the log reduction of bacteria colony-forming units, is selected as the indicator of the plasma biological effect. A model establishing the relationship between the ETOP and BRF is presented. For the first try of this paper, a linear relationship between the lgETOP and BRF is assumed. The model is initially validated by the published data from the literature. Further simulation and experiment are also conducted, and the positive correlation between the ETOPs and BRFs in the model again suggests that the ETOP could be a reasonable solution as the plasma dose. Finally, the prospects for improving the ETOP, such as including RONS generated in liquid phase, evaluating the weight factor of each type RONS, and involving the effect of electrons, ions, and UV/VUV, are discussed.

Development of a species-specific polymerase chain reaction for highly sensitive detection of Flavobacterium columnare targeting chondroitin AC lyase gene

Columnaris disease, caused by Flavobacterium columnare, is an acute infection of gills and fins, that exists worldwide and causes remarkable losses in freshwater fish. The 16S rRNA gene is not a good candidate for primer design, since this gene has high identity among species in the same genus. In the present study, we developed a species-specific PCR for detection of Flavobacterium columnare based on the chondroitin AC lyase (cslA) gene. The cslA gene sequence from 13 F. columnare strains were aligned to design a specific primer set, Fcol-F and Fcol-R, based on conserved region of the gene. The new primer set produced a specific amplicon of 287 bp from 83 isolates of F. columnare but not from related or other bacterial pathogens. The PCR was sensitive and detected up to 3 pg of genomic DNA and as few as 7 colony-forming units of bacteria. The sensitivity was decreased tenfold when F. columnare gDNA was spiked into tissue samples. The designed primers precisely amplified F. columnare from skin and gills of infected fish, but not in those of clinically healthy fish, reflecting their possible use for diagnostic purposes.

Influence of Cry1Ac Toxin From Bt Cotton on the Soil Microbiota

The first record of transgenic cotton cultivation in Brazil was in 2005, of that of the cultivar MON 531, possessing the cry1Ac gene. Since then, no evaluation has been performed to understand whether the cultivation of Bt cotton has caused any interference with the soil microbiota, including bacteria. In this context, our research was aimed to assess whether the cultivation of Bt cotton negatively affects the community of soil bacteria, through quantitative and metagenomic analyses (marker gene 16S rRNA) for phylum identification. Samples of bacterial populations obtained from the soil cultivated with Bt cotton expressing the Cry1Ac toxin were compared with soil samples from the area cultivated with conventional cotton. Significant differences were not observed in the measure of colony-forming units of bacteria between the soils cultivated with Bt and non-Bt cotton; however, differences were detected only when comparing samples from different collection times of the Bt treatment. Cultivation of Bt cotton did not affect the diversity of the soil bacterial population. Overall, our study shows that, similar to most of the works that have been reported worldwide, cultivation of transgenic cotton does not seem to affect the quantity and diversity of natural soil bacteria.

Evaluation of Antimicrobial Efficacy and Penetration Depth of Various Irrigants into the Dentinal Tubules with and without Lasers: A Stereomicroscopic Study.

ABSTRACTAimTo evaluate and compare the antibacterial efficacy and horizontal depth of penetration of various irrigants into the dentinal tubules when used alone and when combined with lasers.Materials and methodsAn experimental study was done on 42 single-rooted teeth. Access cavity preparation was done and the canals were enlarged up to a ProTaper file size F2 of length 25 mm. They were inoculated with 0.1 mL of Enterococcus faecalis and the samples were randomly assigned into six different groups of seven teeth each. The following irrigation systems were used individually and in combinations—normal saline, sodium hypochlorite, chlorhexidine gluconate, diode laser and erbium, chromium: ytrrium scandium gallium garnet laser (Er,Cr:YSGG laser). The colony-forming units (CFU) of bacteria before and after disinfection and the penetration depth of different groups were determined. Statistical analysis was done by an ANOVA test.ResultsThe highest number of CFU of bacteria was shown by the group where saline was used and it also showed the least penetration depth compared to that of the Er,Cr:YSGG laser group.ConclusionEr,Cr:YSGG laser when used along with sodium hypochlorite and chlorhexidine gluconate showed the highest reduction in the CFU of bacteria and the greatest penetration depth when observed under a stereomicroscope.Clinical significanceLaser-assisted irrigation regimes have a high antibacterial efficacy and more penetration depth into the dentinal tubules.How to cite this articleSubramani SM, Anjana G, et al. Evaluation of Antimicrobial Efficacy and Penetration Depth of Various Irrigants into the Dentinal Tubules with and without Lasers: A Stereomicroscopic Study. Int J Clin Pediatr Dent 2019;12(4):273–279.

Dose-interval study of a dual probiotic in preterm infants

ObjectiveThe objective of this study was to investigate the appropriate dosing interval of a probiotic (Infloran) given daily, biweekly and weekly in preterm infants <32 weeks’ gestation.MethodsThere were 8 infants...

Tat-functionalized liposomes for the treatment of meningitis: an in vitro study.

Bacterial meningitis has become a global concern, because of the emergence of antibiotic-resistant bacteria. It has been demonstrated that liposomes can enter bacteria, thus providing a possible treatment for numerous infections, including meningitis. Fusogenic liposomes are pH-sensitive with a high capacity to fuse with the bacteria membrane and promote intracellular drug release. Moreover, this ability can be improved by using cell-penetrating peptides (such as Tat47–57, which is a peptide derived from the Tat protein of HIV). The purpose of this in vitro study was to demonstrate for the first time the ability of the presently prepared fusogenic liposomes, which were spherical particles with a diameter of 100 nm loaded with antibiotics and functionalized with-cell penetrating peptides (Tat47–57), to fight the main bacteria that cause meningitis. For this, vancomycin, methicillin, and ampicillin antibiotics were loaded inside fusogenic liposomes to fight Streptococcus pneumoniae, methicillin-resistant Staphylococcus aureus, and Escherichia coli. Antibacterial activity of Tat-functionalized and nonfunctionalized liposomes loaded with antibiotics was tested by determining bacteria colony-forming units and growth-curve assays coupled with live/dead assays using fluorescence microscopy. Results showed a remarkable decrease in antibiotic minimum inhibitory concentration when all of the bacteria were treated with these novel liposomes, especially for the functionalized liposomes loaded with methicillin. With antibiotic concentrations of 1.7–3 µg/mL for Tat-functionalized liposomes loaded with methicillin, the bacteria population was totally eradicated. Cytotoxicity tests with astrocytes and endothelial cells, major cellular components of the blood–brain barrier, were also performed for all of the liposomes, including free antibiotic and the Tat peptide. Results showed much promise for the further study of the presently formulated liposomes to treat meningitis.

Protective effects of recombinant trichinella spiralis-53 000 protein combining with imipenem on polymicrobial septic mice

To observe the protective effects of recombinant trichinella spiralis-53 000 protein (rTsP53 protein) combining with imipenem (IMP) on septic mice and their underlying mechanisms. . Male BALB/c mice were divided into five groups randomly. Cecal ligature and puncture (CLP) operation was used for building polymicrobial septic model (CLP group).Mice in sham group were only subjected to laparoromy and abdominal closure without cecum ligation. At 6 hours post CLP, mice in CLP+IMP,CLP+rTsP53,and CLP+IMP+rTsP53 groups were injected intraperitoneally with IMP (20 mg/kg) + 0.1 mL albumin,rTsP53 protein (6 mg/kg) + 0.1 mL normal saline (NS),IMP (20 mg/kg) + rTsP53 protein (6 mg/kg) respectively, mice in sham group and CLP group were injected intraperitoneally with 0.1 mL albumin + 0.1 mL NS, then these therapies were repeated every 12 hours until the experiment ended. Twenty mice were extracted randomly from each group for surveying 72-hour survival rate.At 0,6,12,24,36,48,72 hours post CLP,3 mice in each group were collected and cytokines in serum were tested by enzyme-linked immunosorbent assay (ELISA).Whole blood was cultured, then the numbers of bacteria colony-forming units (CFU) were counted. Mice were executed at 24 hours, then the epithelial cells ultrastructures of the mice small intestinal mucosa were observed by transmission electron microscope (TEM). ① Compared with CLP,CLP+IMP or CLP+rTsP53 group,72-hour survival rate of the mice in CLP+IMP+rTsP53 group was significantly elevated (85％ vs.20％,55％,25％,all P ＜ 0.05).② No bacteria was found in cultured whole blood of mice in sham group at all time-points. At 6 hours post CLP operation, the number of bacterial clone of all experimental groups was rose significantly. The changed trend of bacterial number in CLP group was rising at the beginning, then declining, and the bacterial number reached the peak at 24 hours (× 106 cfu/L:12.74± 2.33).From 12 hours, the bacterial numbers of CLP+rTsP53 group were higher than those of CLP group, and reached the peak at 36 hours (× 106 cfu/L:22.13 ± 4.28),then declined gradually. The bacterial numbers of CLP+IMP and CLP+IMP+rTsP53 groups reached the peak at 6 hours (× 106 cfu/L:5.72 ± 0.50,5.49 ± 0.59),then declined. They were significantly less than those of CLP group from 12 hours.③ From 6 hours after CLP,the cytokines levels of mice in all experimental groups were higher than those in sham group. The tumor necrosis factor-α (TNF-α) levels in CLP group showed a trend of elevation in the beginning, and decrease thereafter. It reached the peak at 36 hours (ng/L:1 422.67 ±72.19).The TNF-α level peak time of CLP+IMP group,CLP+rTsP53 group,CLP+IMP+rTsP53 group was advanced to 12 hours post CLP (ng/L:1376.29±44.67,929.36±40.42,809.61±22.61).At 24 hours post CLP, the interleukin-6 (IL-6) level of CLP group and CLP+IMP group reached the peak (ng/L:215.39 ± 16.05,191.63 ± 8.99).The peak time of CLP+rTsP53 group and CLP+IMP+rTsP53 was advanced to 12 hours post CLP (ng/L:113.01 ± 12.11,92.43±6.11).The level of IL-4,IL-10 in CLP group raised gradually to the highest at 72 hours (ng/L:366.25 ±24.25,923.14±30.36).The IL-4 and IL-10 levels of CLP+IMP group raised to their maximum value at 12 hours and 24 hours respectively (ng/L:281.47±16.33,555.67±13.57),then declined. The IL-4 and IL-10 levels of CLP+rTsP53 group and CLP+IMP+rTsP53 group gradually ascended their peak value at 72 hours [IL-4 (ng/L) was 453.14±18.53,410.43 ± 15.75,IL-10 (ng/L) was 1 185.61 ± 16.74,1 006.77 ± 36.91,respectively].From 12 hours, the pro-inflammatory cytokines levels of CLP+IMP+rTsP53 group were significantly less than those of CLP+IMP group and CLP+rTsP53 group.④ At 24 hours post CLP, compared with mice in CLP,CLP+IMP, or CLP+rTsP53 group, mice in CLP+IMP+rTsP53 group had slighter ultra structure injuries in the microvilli, cell junction and mitochondria of small intestinal mucosa epithelial cells. The levels of pro-inflammatory cytokines were reduced and the levels of anti-inflammatory eytokines were escalated by intervention of rTsP53 protein combining with IMP boosted in polymierobial septic mice serum, and enhanced the survival rate of the mice. The injection of rTsP53 protein alone had no protective effects on polymicrobial septic mice,because the amount of bacteria in mice blood was augmented

Interaction of drug- and granulocyte-mediated killing of Pseudomonas aeruginosa in a murine pneumonia model.

Killing of bacterial pathogens by granulocytes is a saturable process, as previously demonstrated. There is virtually no quantitative information about how granulocytes interact with antimicrobial chemotherapy to kill bacterial cells. We performed a dose-ranging study with the aminoglycoside plazomicin against Pseudomonas aeruginosa ATCC27853 in a granulocyte-replete murine pneumonia model. Plazomicin was administered in a humanized fashion (ie, administration of decrementing doses 5 times over 24 hours, mimicking a human daily administration profile). Pharmacokinetic profiling was performed in plasma and epithelial lining fluid. All samples were simultaneously analyzed with a population model. Mouse cohorts were treated for 24 hours; other cohorts treated with the same therapy were observed for another 24 hours after therapy cessation, allowing delineation of the therapeutic effect necessary to reduce the bacterial burden to a level below the half-saturation point. The mean bacterial burden (±SD) at which granulocyte-mediated kill was half saturable was 2.45 × 10(6) ± 6.84 × 10(5) colony-forming units of bacteria per gram of tissue (CFU/g). Higher levels of plazomicin exposure reduced the bacterial burden to <5 log10 CFU/g, allowing granulocytes to kill an additional 1.0-1.5 log CFU/g over the subsequent 24 hours. For patients with large bacterial burdens (eg, individuals with ventilator-requiring hospital-acquired pneumonia), it is imperative to kill ≥2 log10 CFU/g early after treatment initiation, to allow the granulocytes to contribute optimally to bacterial clearance.

Investigations of the capacity and strength of seed germination in Allium victorialis L.

&lt;p&gt;The aim of the study was to examine the strength and energy of seed germination in &lt;em&gt;Allium victorialis&lt;/em&gt;. Despite the normal structure of seeds containing a viable embryo and compliance with all International Seed Testing Association recommendations, no germination in &lt;em&gt;A. victorialis&lt;/em&gt; was observed. Additionally, the scarification and stratification treatments applied did not improve the dynamics of germination of &lt;em&gt;A. victorialis&lt;/em&gt; seeds. Microbiological analyses of soil sampled from natural localities of the plant revealed a typical composition of bacteria and fungi. The high number of fungi [4.5 log&lt;sub&gt;10&lt;/sub&gt;CFU (colony forming units) of fungi × g&lt;sup&gt;−1&lt;/sup&gt; dry mass of soil] and various groups of bacteria (about 7.0 log&lt;sub&gt;10&lt;/sub&gt;CFU of bacteria × g&lt;sup&gt;−1&lt;/sup&gt; dry mass of soil) were detected in the root-free-soil around garlic roots. In the interior of &lt;em&gt;A. victorialis&lt;/em&gt; roots, the number of microorganisms decreased 1000 to 10 000 times but all the tested microbial groups, especially copiotrophic bacteria and fungi (1.6 and 2.2, respectively, log&lt;sub&gt;10&lt;/sub&gt;CFU × g&lt;sup&gt;−1&lt;/sup&gt; dry mass of roots) were detected.&lt;/p&gt;&lt;p&gt;Changes in such parameters as dehydrogenase activity, pH values, and the total organic C (TOC) content in the particular parts of the rhizosphere and in comparison to the rhizosphere with root-free-soil were observed. The dehydrogenase activity and TOC content were highly positively correlated with the total number of CFU of the microorganisms.&lt;/p&gt;