Coli Colony-forming Units Research Articles

Exploring powder metallurgy-processed Ti–25Ta-xCu alloys for potential biomedical applications

The prevalence of certain bone-related disorders, the advancing age of the population, and routine incidents all contribute to an escalating demand for orthopedic and dental implants. Consequently, there is a growing emphasis on exploring novel material options that can efficiently replace the affected regions. In this study, Ti–25Ta alloys with small amounts of copper (1, 3, and 5 vol%) were developed via powder metallurgy to limit manufacturing costs and induce new functionality on the materials, including antibacterial response. The addition of copper further stabilized the beta titanium phase, promoted the formation of the Ti2Cu phase, slightly increased the microhardness and elasticity modulus of the alloys, and enhanced their corrosion resistance in simulated body fluid (SBF) at 37 °C. All sintered materials exhibited a bacteriostatic response when exposed to bacterial strains of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. It was observed that higher copper content correlated with a decrease in Escherichia coli colony-forming units (CFU). Based on all conducted evaluations, the Ti–25Ta–5Cu alloy demonstrated the highest potential for future use in the field of biomedical applications.

Agro-industrial by-products as alternative additives for the agronomic valorization of pig slurry through pH modification

The use of animal slurry in modern agricultural systems is receiving considerable attention, mainly due to the latest increase in chemical fertilizer prices. However, the use of raw animal slurry to fertilize horticultural crops can, on the one hand, lead to significant ammonia emissions and, on the other hand, be an important source of zoonotic pathogens. Therefore, proper treatment is required. The present study explored the modification of the pH value of pig slurry using by-products from different agro-industrial activities as a strategy to control these two problems. Three approaches were used, namely acidification and biological acidification (bio-acidification) to pH 5 and alkalization to pH 9.5. The most promising of the 14 different additives and additive combinations initially considered should be able to reach the target pH at a dose of less than 20% (m/m). The presence of Salmonella and the number of Escherichia coli colony forming units (CFU) were evaluated in the slurry for each selected treatment. To ensure that treated slurry remains of interest as an organic fertilizer, the impact of treated slurry on plant germination and nitrogen (N) availability was also assessed. The by-products from the brewing and yeast industry failed to reduce the pH to 5. In fact, the bio-acidification of pig slurry was only possible with additives rich in carbon. Although slurry sanitization (<1000 CFU E.coli g−1 slurry) was not guaranteed by all treatments, a reduction in E.coli numbers was observed with all additives. The ammonium content of the treated slurry was significantly reduced (up to 20%) with treatments involving bio-acidification. N mineralization was evidenced for all additives used for slurry alkalinization but no N mineralization was observed when using acidification with H2SO4 or by-product spent acid. The phytotoxicity bioassay showed that most additives do not have a negative impact on germination. The results presented here suggest that agro-industrial by-products are capable of modifying the pH of pig slurry. Depending on the pH modification strategy and additive used, treated slurry may be safer and of higher fertilizing value than untreated (raw) slurry.

Partial replacement of soybean meal with full-fat black soldier fly larvae meal in plant-based nursery diets did not influence fecalEscherichia colicolony forming units or improve fecal consistency when pigs were weaned into non-disinfected pens

AbstractAt weaning, one hundred pigs (21 d of age; 6.96 ± 0.23 kg BW) were used to determine the effect of partially replacing soybean meal (SBM) in corn- and SBM-based nursery diets on growth performance, fecal scores, Escherichia coli (E. coli) colony forming units (CFU), and cecal mucosal microbial profile when weaned into non-disinfected nursery pens. Pens were randomly assigned to one of four dietary treatments (n = 5): high-complexity (contained highly digestible animal proteins and 10.8% SBM) with and without 3,000 ppm ZnO (HC + and HC−, respectively; representative of commercial diets), low-complexity (corn- and SBM-based; 31.8% SBM; LC), or LC with 30% inclusion of full-fat black soldier fly larvae meal (BSFLM) to partially replace SBM (LCFL; 8.0% SBM). Diets were fed for 14 d (phase I), followed by 4 wk of a common corn-SBM diet (phase II). Fecal E. coli CFU and cecal mucosal microbial 16s rRNA community profiles were assessed 7 d after weaning. During phase I, pigs fed LC and LCFL had lower average daily gains (P &amp;lt; 0.05) than pigs fed HC + and HC−, which were not different. Average daily feed intake was not different for pigs fed LC and LCFL, but lower than for pigs fed HC− (P &amp;lt; 0.001); pigs fed HC + had greater feed intake in phase I vs. all other treatment groups (P &amp;lt; 0.001). Upon nursery exit, only pigs fed LCFL had lower BW than pigs fed HC− (P &amp;lt; 0.05), with intermediate values observed for HC + and LC. Day 3 fecal scores were greater for pigs fed LCFL vs. HC + (P &amp;lt; 0.05) and day 7 E. coli CFU were greater for all treatment groups vs. HC + (P &amp;lt; 0.001). Pigs fed HC− (P &amp;lt; 0.01), LC (P &amp;lt; 0.05), and LCFL (P &amp;lt; 0.05) had lower alpha diversity for cecal mucosal microbiota compared to HC+. At the genus level, pigs fed LC had lower Lactobacillus relative abundance vs. pigs fed HC + (P &amp;lt; 0.01). Therefore, BSFLM can partially replace SBM without sacrificing growth performance vs. nursery pigs fed corn- and SBM-based diets, but both groups had reduced phase I growth performance vs. pigs fed highly digestible diets containing animal proteins when weaned into non-disinfected pens. The BSFLM did not influence fecal E. coli CFU or improve fecal consistency after weaning and therefore, is less effective at minimizing digestive upsets vs. HC + diets.

Static Magnetic Field Inhibits Growth of Escherichia coli Colonies via Restriction of Carbon Source Utilization.

Magnetobiological effects on growth and virulence have been widely reported in Escherichia coli (E. coli). However, published results are quite varied and sometimes conflicting because the underlying mechanism remains unknown. Here, we reported that the application of 250 mT static magnetic field (SMF) significantly reduces the diameter of E. coli colony-forming units (CFUs) but has no impact on the number of CFUs. Transcriptomic analysis revealed that the inhibitory effect of SMF is attributed to differentially expressed genes (DEGs) primarily involved in carbon source utilization. Consistently, the addition of glycolate or glyoxylate to the culture media successfully restores the bacterial phenotype in SMF, and knockout mutants lacking glycolate oxidase are no longer sensitive to SMF. These results suggest that SMF treatment results in a decrease in glycolate oxidase activity. In addition, metabolomic assay showed that long-chain fatty acids (LCFA) accumulate while phosphatidylglycerol and middle-chain fatty acids decrease in the SMF-treated bacteria, suggesting that SMF inhibits LCFA degradation. Based on the published evidence together with ours derived from this study, we propose a model showing that free radicals generated by LCFA degradation are the primary target of SMF action, which triggers the bacterial oxidative stress response and ultimately leads to growth inhibition.

Evaluation of E. coli in sediment for assessing irrigation water quality using machine learning

Fresh produce irrigated with contaminated water poses a substantial risk to human health. This study evaluated the impact of incorporating sediment information on improving the performance of machine learning models to quantify E. coli level in irrigation water. Field samples were collected from irrigation canals in the Southwest U.S., for which meteorological, chemical, and physical water quality variables as well as three additional flow and sediment properties: the concentration of E. coli in sediment, sediment median size, and bed shear stress. Water quality was classified based on E. coli concentration exceeding two standard levels: 1 E. coli and 126 E. coli colony forming units (CFU) per 100 ml of irrigation water. Two series of features, including (FIS) and excluding (FES) sediment features, were selected using multi-variant filter feature selection. The correlation analysis revealed the inclusion of sediment features improves the correlation with the target standards for E. coli compared to the models excluding these features. Support vector machine, logistic regression, and ridge classifier were tested in this study. The support vector machine model performed the best for both targeted standards. Besides, incorporating sediment features improved all models' performance. Therefore, the concentration of E. coli in sediment and bed shear stress are major factors influencing E. coli concentration in irrigation water.

Iron oxide-mediated photo-Fenton catalysis in the inactivation of enteric bacteria present in wastewater effluents at neutral pH

The pressure on natural water resources associated with increasing water scarcity highlights the value of using reclaimed water through the development of efficient and environmentally friendly treatment technologies. In this work, the use of magnetic nanoparticles in photo-Fenton catalysis for water disinfection was considered to inactivate natural enteric bacteria present in municipal wastewater effluents under white light and neutral pH. The most recommended ranges were evaluated in key variables such as the loading and composition of nanoparticles (NPs), hydrogen peroxide (H2O2) concentration, the light source (UV and visible) and treatment time were evaluated in wastewater disinfection expressed in terms of total coliforms and Escherichia coli colony forming units (CFU). The magnetic separation of NPs allowed the disinfection process to be carried out in different cycles, facilitating the recovery of the nanocatalyst and avoiding its discharge with the treated effluent.

Advancing Understanding of Land Use and Physicochemical Impacts on Fecal Contamination in Mixed-Land-Use Watersheds

Understanding mixed-land-use practices and physicochemical influences on Escherichia (E.) coli concentrations is necessary to improve water quality management and human health. Weekly stream water samples and physicochemical data were collected from 22 stream gauging sites representing varying land use practices in a contemporary Appalachian watershed of the eastern USA. Over the period of one annual year, Escherichia (E.) coli colony forming units (CFU) per 100 mL were compared to physicochemical parameters and land use practices. Annual average E. coli concentration increased by approximately 112% from acid mine drainage (AMD) impacted headwaters to the lower reaches of the watershed (approximate averages of 177 CFU per 100 mL vs. 376 CFU per 100 mL, respectively). Significant Spearman’s correlations (p &lt; 0.05) were identified from analyses of pH and E. coli concentration data representing 77% of sample sites; thus highlighting legacy effects of historic mining (AMD) on microbial water quality. A tipping point of 25–30% mixed development was identified as leading to significant (p &lt; 0.05) negative correlations between chloride and E. coli concentrations. Study results advance understanding of land use and physicochemical impacts on fecal contamination in mixed-land-use watersheds, aiding in the implementation of effective water quality management practices and policies.

Caution at choosing a particular colony-forming unit from faecal Escherichia coli: it may not represent the sample profile.

Data about phylogenetic classification of Escherichia coli colonizing calves, lambs and foals are routinely neglected and restricted to outdated methodologies, even in the context of antimicrobial susceptibility (AS) testing. Thus, the aim of this study was to determine the phylogenetic diversity and the AS profile of E. coli colony-forming units (CFUs) from faecal samples of healthy animals. Five CFUs of E. coli were randomly selected from each faecal culture of calves (n=13), foals (n=13) and lambs (n=13), totalizing 195 CFUs phylo-typed by quadruplex PCR. The AS profile of five CFUs from 15 samples (five from each animal species; n=75 isolates) against nine drugs was determined by agar diffusion test. We found E. coli belonging to all phylo-groups already described, except D group, with the predominance of B1 (65% CFUs; 126/195) in the three-animal species sampled. Most faecal samples of calves (77%; 10/13) and foals (69%; 9/13) harboured both pathogenic and nonpathogenic E. coli. All faecal samples showed CFUs with diverse AS profile, highlighting the ineffectiveness of tetracycline, sulphonamide and ampicillin. As a key point, our data reinforce the importance to select at least four E. coli CFUs for AS testing. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides relevant data about the high phylogenetic and antimicrobial susceptibility diversity observed in Escherichia coli colony-forming units (CFUs) from a bacteriological culture of faeces from healthy calves, foals and lambs. The selection pressure exerted by the herd treatment may directly impact the intestinal microflora of animals that have never been treated. Finally, we emphasize the importance of Clinical Laboratory Standards Institute guidelines and we recommended to analyse at least four E. coli CFUs to determine, in particular, the antimicrobial susceptibility profile of faecal isolates, independent of the animal's health status.

Safely Managed Hygiene: A Risk-Based Assessment of Handwashing Water Quality.

Sustainable Development Goal (SDG) Indicator 6.2.1 requires household handwashing facilities to have soap and water, but there are no guidelines for handwashing water quality. In contrast, drinking water quality guidelines are defined: water must be "free from contamination" to be defined as "safely managed" (SDG Indicator 6.1.1). We modeled the hypothesized mechanism of infection due to contaminated handwashing water to inform risk-based guidelines for microbial quality of handwashing water. We defined two scenarios that should not occur: (1) if handwashing caused fecal contamination, indicated using Escherichia coli, on a person's hands to increase rather than decrease and (2) if hand-to-mouth contacts following handwashing caused an infection risk greater than an acceptable threshold. We found water containing <1000 E. coli colony-forming units (CFU) per 100 mL removes E. coli from hands with>99.9% probability. However, for the annual probability of infection to be <1:1000, handwashing water must contain <2 × 10-6 focus-forming units of rotavirus, <1 × 10-4 CFU of Vibrio cholerae, and <9 × 10-6 Cryptosporidium oocysts per 100 mL. Our model suggests that handwashing with nonpotable water will generally reduce fecal contamination on hands but may be unable to lower the annual probability of infection risks from hand-to-mouth contacts below 1:1000.

Microbiota stability in healthy individuals after single-dose lactulose challenge-A randomized controlled study.

Background and aimsLactulose is a common food ingredient and widely used as a treatment for constipation or hepatic encephalopathy and a substrate for hydrogen breath tests. Lactulose is fermented by the colon microbiota resulting in the production of hydrogen (H2). H2 is a substrate for enteropathogens including Salmonella Typhimurium (S. Typhimurium) and increased H2 production upon lactulose ingestion might favor the growth of H2-consuming enteropathogens. We aimed to analyze effects of single-dose lactulose ingestion on the growth of intrinsic Escherichia coli (E. coli), which can be efficiently quantified by plating and which share most metabolic requirements with S. Typhimurium.Methods32 healthy volunteers (18 females, 14 males) were recruited. Participants were randomized for single-dose ingestion of 50 g lactulose or 50 g sucrose (controls). After ingestion, H2 in expiratory air and symptoms were recorded. Stool samples were acquired at days -1, 1 and 14. We analyzed 16S microbiota composition and abundance and characteristics of E. coli isolates.ResultsLactulose ingestion resulted in diarrhea in 14/17 individuals. In 14/17 individuals, H2-levels in expiratory air increased by ≥20 ppm within 3 hours after lactulose challenge. H2-levels correlated with the number of defecations within 6 hours. E. coli was detectable in feces of all subjects (2 x 102–109 CFU/g). However, the number of E. coli colony forming units (CFU) on selective media did not differ between any time point before or after challenge with sucrose or lactulose. The microbiota composition also remained stable upon lactulose exposure.ConclusionIngestion of a single dose of 50 g lactulose does not significantly alter E. coli density in stool samples of healthy volunteers. 50 g lactulose therefore seems unlikely to sufficiently alter growth conditions in the intestine for a significant predisposition to infection with H2-consuming enteropathogens such as S. Typhimurium (www.clinicaltrials.gov NCT02397512).

Effective Purification of Water from Iron Ions and Potentially Pathogenic Microorganisms Using a Montmorillonite Composite Sorbent

The use of the developed composite sorbent based on the plant wastes (sunflower seed husks) and montmorillonite clay was shown to be highly effective for water purification from iron ions and potentially pathogenic microorganisms. It was shown experimentally that the developed composite sorbent at concentrations of up to 50 mg/L is capable of purifying water from iron ions under static and dynamic conditions. When a suspension of Escherichia coli was filtered at a rate of 10 mL/min, 1 g of the composite sorbent adsorbed 556 million E. coli colony-forming units (CFUs), showing that the sorbent is 1.7 times more effective than the complex sorbent of the replaceable Barrier-4 filter cartridge.

The Effect of Urine Concentration and pH on the Growth of Escherichia Coli in Canine Urine In Vitro.

BackgroundLower urinary tract infections are common in dogs, and Escherichia coli is the most common bacterial pathogen isolated. The literature has conflicting evidence regarding the inhibitory effects of urine concentration and pH on E. coli growth.Hypothesis/ObjectivesTo determine the effect of different pH and urine concentrations on E. coli growth in vitro.AnimalsVoided urine samples from 10 apparently healthy spayed female dogs were used.MethodsA matrix of 9 urine specific gravity (USG; 1.010, 1.020, and 1.030) and pH (5.5, 7.0, and 8.5) combinations was prepared by diluting and titrating filtered voided urine samples. Three E. coli isolates were obtained from urine of female dogs with signs of lower urinary tract infection and cultured at different urine pH and USG combinations in wells of a microtiter plate. The number of E. coli colony‐forming units (CFU) per mL of urine was calculated after aerobic incubation of the urine at 37°C for 18 hours, and statistically compared.ResultsSignificant differences were identified in the mean log CFU/mL among different combinations of pH and USG. The lowest log CFU/mL were observed in alkaline concentrated urine (pH 8.5 and USG 1.030).Conclusions and Clinical Importance Escherichia coli in vitro growth was higher in neutral to acidic and diluted urine compared to alkaline and concentrated urine. The impact of non‐alkalizing diluting diets on the incidence of E. coli lower urinary tract infections should be further explored.

\u0392eta 2-glycoprotein I protects mice against gram-negative septicaemia in a sexually dimorphic manner

The immune responses of males and females to bacterial infections display differences. The mechanisms that underlie this sexual dimorphism are multifactorial. Lipopolysaccharide (LPS) contributes to the pathogenesis of endotoxaemia. We have previously demonstrated that the plasma protein beta-2 glycoprotein-1 (β2GPI) reduces LPS-induced inflammation in male mice. In the present study using a more robust infection model of septicaemia the role of β2GPI is examined in both male and female wild type (WT) and β2GPI deficient (β2GPI−/−) mice challenged with Escherichia coli (E. coli) intravenously. β2GPI deficiency led to an increase of E. coli colony forming units (CFU) in the circulation of both male and female mice. In male β2GPI−/− mice this was associated with a worse clinical severity score. This difference was not observed between female β2GPI−/− and female WT mice. Male WT mice had decreased levels of total and increased levels of free thiol β2GPI following administration of LPS or E. coli. This pattern of sexual dimorphic response was also observed in our cohort of humans with sepsis. These findings support a role for β2GPI in modulating the sex-specific susceptibility to gram-negative septicaemia.

Timing of valproic acid in acute lung injury: prevention is the best therapy?

BackgroundAcute lung injury and respiratory distress syndrome is characterized by uncontrolled inflammation of the lungs after a severe inflammatory stimulus. We have previously demonstrated an ameliorated syndrome and improved survival in mice with early administration of valproic acid (VPA), a broad-spectrum histone deacetylase inhibitor, while studies in humans have shown no benefit when anti-inflammatories are administered late. The current study tested the hypothesis that early treatment would improve outcomes in our gram-negative pneumonia-induced acute lung injury. Materials and methodsMice (C57BL/6) had 50 × 106 Escherichia coli (strain 19,138) instilled endotracheally and VPA (250 mg/kg) administered intraperitoneally 3, 4, 6, and 9 h (n = 12/group) later. Six hours after VPA administration, the animals were sacrificed, and bronchoalveolar lavage (BAL) fluid interleukin-6 (IL-6), tumor necrosis factor, neutrophils and macrophages as well as the E coli colony-forming units were quantified. Plasma IL-6 was also measured. A separate group of mice (n = 12/group) were followed prospectively for 7 days to assess survival. ResultsBAL IL-6 and tumor necrosis factor as well as plasma IL-6 were significantly lower in the animals administered VPA within 3 h (P < 0.05) but not when administered later (4, 6, 9 h). There was no difference in the BAL E coli colony-forming units, macrophage, or neutrophil numbers at any time point. Survival improved only when VPA was administered within 3 h. ConclusionsA narrow therapeutic window exists in this murine model of gram-negative pneumonia-induced acute lung injury and likely explains the lack of response in studies with late administration of anti-inflammatory therapies in clinical studies.

Effects of digestate on soil chemical and microbiological properties: A comparative study with compost and vermicompost

Anaerobic digestion has become increasingly popular as an alternative for recycling wastes from different origins. Consequently, biogas residues, most of them with unknown chemical and biological composition, accrue in large quantities and their application into soil has become a widespread agricultural practise. The aim of this study was to evaluate the effects of digestate application on the chemical and microbiological properties of an arable soil in comparison with untreated manure, compost and vermicompost. Once in the soil matrix either the addition of compost or digestate led to an increased nitrification rate, relative to unamended and manure-treated soil, after 15 and 60 days of incubation. Faecal coliform and E. coli colony forming units (CFUs) were not detected in any of the amended soils after 60 days. The highest number of Clostridium perfringens CFUs was recorded in manure-amended soil at the beginning of the experiment and after 15 days; whilst after 60 days the lowest CFU number was registered in digestate-treated soil. Denaturing gradient gel electrophoresis patterns also showed that besides the treatment the date of sampling could have contributed to modifications in the soil ammonia-oxidising bacteria community, thereby indicating that the soil itself may influence the community diversity more strongly than the treatments.

Time-Varying Causal Effects of Bacteremia and Sepsis on 5-Year Risk of Cardiovascular Events

Fresh produce irrigated with contaminated water poses a substantial risk to human health. This study evaluated the impact of incorporating sediment information on improving the performance of machine learning models to quantify E. coli level in irrigation water. Field samples were collected from irrigation canals in the Southwest U.S., for which meteorological, chemical, and physical water quality variables as well as three additional flow and sediment properties: the concentration of E. coli in sediment, sediment median size, and bed shear stress. Water quality was classified based on E. coli concentration exceeding two standard levels: 1 E. coli and 126 E. coli colony forming units (CFU) per 100 ml of irrigation water. Two series of features, including (FIS) and excluding (FES) sediment features, were selected using multi-variant filter feature selection. The correlation analysis revealed the inclusion of sediment features improves the correlation with the target standards for E. coli compared to the models excluding these features. Support vector machine, logistic regression, and ridge classifier were tested in this study. The support vector machine model performed the best for both targeted standards. Besides, incorporating sediment features improved all models' performance. Therefore, the concentration of E. coli in sediment and bed shear stress are major factors influencing E. coli concentration in irrigation water.

PET imaging of bacterial infections with fluorine-18-labeled maltohexaose.

A positron emission tomography (PET) tracer composed of (18)F-labeled maltohexaose (MH(18)F) can image bacteria in vivo with a sensitivity and specificity that are orders of magnitude higher than those of fluorodeoxyglucose ((18)FDG). MH(18)F can detect early-stage infections composed of as few as 10(5) E. coli colony-forming units (CFUs), and can identify drug resistance in bacteria in vivo. MH(18)F has the potential to improve the diagnosis of bacterial infections given its unique combination of high specificity and sensitivity for bacteria.

PET Imaging of Bacterial Infections with Fluorine‐18‐Labeled Maltohexaose

AbstractA positron emission tomography (PET) tracer composed of 18F‐labeled maltohexaose (MH18F) can image bacteria in vivo with a sensitivity and specificity that are orders of magnitude higher than those of fluorodeoxyglucose (18FDG). MH18F can detect early‐stage infections composed of as few as 105 E. coli colony‐forming units (CFUs), and can identify drug resistance in bacteria in vivo. MH18F has the potential to improve the diagnosis of bacterial infections given its unique combination of high specificity and sensitivity for bacteria.

Efeitos do plasma sanguíneo sobre o crescimento, desenvolvimento bacteriano e estrutura intestinais de leitões desmamados aos 28 dias de idade

Visando-se determinar se o plasma sangüíneo tem efeitos sobre o crescimento, o desenvolvimento bacteriano e a estrutura intestinal de leitões desmamados aos 28 dias de idade consumindo quantidades iguais de dietas, 24 leitões desmamados aos 28 dias de idade foram utilizados em um experimento com delineamento em blocos ao acaso com quatro tratamentos (dietas com 0,0; 2,5; 5,0 e 7,5% de plasma sangüíneo), seis repetições e um animal por unidade experimental. Foram constatadas diferenças significativas entre os tratamentos em relação aos ganhos de peso, às conversões alimentares e às quantidades de colônias de E. coli. Os animais que consumiram as dietas com plasma sangüíneo apresentaram maiores ganhos de peso, melhores conversões alimentares e menores quantidades de E. coli no intestino delgado do que os animais que receberam dietas sem plasma. Não se observou efeitos significativos das quantidades de plasma sangüíneo consumido sobre a estrutura intestinal dos leitões doze dias após o desmame. Concluiu-se que a inclusão de plasma sangüíneo na proporção mínima de 2,5% aumenta ganho de peso, melhora conversão alimentar e reduz a incidência de colônias de E. coli no intestino de leitões desmamados aos 28 dias de idade criados em condições de desafio, mas não afeta a estrutura intestinal.

Evaluation of oral administration of bacteriophages to neonatal calves: Phage survival and impact on fecal Escherichia coli

Diarrhea is an important cause of morbidity and mortality in neonatal calves. Several enteropathogens are associated with diarrhea in young calves, with Enterotoxigenic Escherichia coli (ETEC) infection being the most common type of colibacillosis. The rise of antibiotic resistance in a number of medically important bacterial pathogens has revived interest in the use of bacteriophages as anti-bacterial therapeutic agents. Here we describe the results of a randomized, placebo-controlled, double-blinded study designed to evaluate the effect of an oral bacteriophage cocktail on fecal E. coli colony-forming units (CFU). Ten calves were enrolled in the study to either the bacteriophage group or the placebo group for 22 feedings. Calves in the bacteriophage treatment group (n=6) received a total of 106 plaque-forming units (PFU) (volume=5ml) of each of four bacteriophages while the placebo group (n=4) received only phosphate-buffered saline (5ml). Fresh fecal samples and blood samples were collected daily from each calf and analyzed for bacterial count and presence of bacteriophage. E. coli-infecting phages were recovered from all phage-treated calves at concentrations of 10² to 10³ PFU per gram of rectal contents, but none was detected in serum. Phage treatment caused a reduction in fecal E. coli when compared to the control group: the mean log CFU for the placebo-treated group was 9.25 (SE=0.42) versus 9.11 (SE=0.34) for the phage-treated group, but the difference was not statistically significant.