The Impact of Bacteriophage on Complex Bacterial Populations in Urban Waterways

2020 ◽  
Vol 34 (S1) ◽  
pp. 1-1
Author(s):  
Abigail Lammers ◽  
Alicia Enz ◽  
Clayton D. Carlson
Keyword(s):  
Bacterial Populations ◽  
Urban Waterways ◽  
The Impact

Bacteriology and Storage Life of Moisture-Enhanced Pork

2003 ◽  
Vol 66 (2) ◽  
pp. 293-299 ◽  
Author(s):  
VALERIE M. BOHAYCHUK ◽  
G. GORDON GREER
Keyword(s):  
Bacterial Contamination ◽  
Lemon Juice ◽  
Storage Life ◽  
Bacterial Populations ◽  
Psychrotrophic Bacteria ◽  
Injection Process ◽  
Spoilage Bacteria ◽  
The Impact ◽  
And Storage ◽  
Brine Injection

This study was undertaken to determine the impact of the moisture enhancement process on the bacterial contamination and storage life of vacuum-packaged pork loins. Bone-in and boneless pork loins injected with brine (sodium chloride, sodium phosphate, lemon juice) were obtained from a commercial processing facility and stored for 5 weeks in vacuum packaging at 2 and 5°C. At weekly intervals, samples were excised to determine numbers of spoilage bacteria and pathogens. The loins were subjectively evaluated by a sensory panel to quantify appearance and odor acceptability. Moisture-enhanced loins were initially contaminated with a population of psychrotrophic bacteria that was approximately 2 log units higher than that for noninjected boneless loins. This difference was largely due to contamination by larger numbers of pseudomonads in the brine-injected loins. There were no significant differences in the initial numbers of lactic acid bacteria, Enterobacteriaceae, or Brochothrix thermosphacta. Similar trends in spoilage bacterial populations were observed for moisture-enhanced loins with bones, but Enterobacteriaceae counts were also found to be approximately 1 log unit higher for the injected product. Brine-injected loins generally had larger bacterial numbers at each storage time, but there were no consistent injection treatment effects on bacterial growth. Brine injection did not affect color or odor deterioration, and the storage life for vacuum-packaged loins was the same as that for noninjected controls. The incidence of Listeria monocytogenes was 21% for control loins and 27% for moisture-enhanced loins. Although the brine injection process resulted in an increase in bacterial contamination, there was no evidence that this contamination would affect the storage life of vacuum-packaged loins, and further research is necessary to determine the significance of the increased incidence of L. monocytogenes.

scholarly journals Heterogenous response to R-pyocin killing in populations of Pseudomonas aeruginosa sourced from cystic fibrosis lungs

2020 ◽  
Author(s):  
Madeline Mei ◽  
Jacob Thomas ◽  
Stephen P. Diggle
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Genotypic Diversity ◽  
Opportunistic Pathogen ◽  
Chronic Infections ◽  
Bacterial Populations ◽  
Heterogeneous Populations ◽  
Lung Infections ◽  
The Impact ◽  
Lps Binding

AbstractBacteriocins are proteinaceous antimicrobials produced by bacteria which are active against other strains of the same species. R-type pyocins are phage tail-like bacteriocins produced by Pseudomonas aeruginosa. Due to their anti-pseudomonal activity, R-pyocins have potential as therapeutics in infection. P. aeruginosa is a Gram-negative opportunistic pathogen and is particularly problematic for individuals with cystic fibrosis (CF). P. aeruginosa from CF lung infections develop increasing resistance to antibiotics, making new treatment approaches essential. P. aeruginosa populations become phenotypically and genotypically diverse during infection, however little is known of the efficacy of R-pyocins against heterogeneous populations. R-pyocins vary by subtype (R1-R5), distinguished by binding to different residues on the lipopolysaccharide (LPS). Each type varies in killing spectrum, and each strain produces only one R-type. To evaluate the prevalence of different R-types, we screened P. aeruginosa strains from the International Pseudomonas Consortium Database (IPCD) and from our biobank of CF strains. We found that (i) R1-types were the most prevalent R-type among strains from respiratory sources and (ii) isolates collected from the same patient have the same R-type. We then assessed the impact of diversity on R-pyocin susceptibility and found a heterogenous response to R-pyocins within populations, likely due to differences in the LPS core. Our work reveals that heterogeneous populations of microbes exhibit variable susceptibility to R-pyocins and highlights that there is likely heterogeneity in response to other types of LPS-binding antimicrobials, including phage.ImportanceR-pyocins have potential as alternative therapeutics against Pseudomonas aeruginosa in chronic infection, however little is known about the efficacy of R-pyocins in heterogeneous bacterial populations. P. aeruginosa is known to become resistant to multiple antibiotics, as well as evolve phenotypic and genotypic diversity over time; thus it is particularly difficult to eradicate in chronic cystic fibrosis (CF) lung infections. In this study, we found that P. aeruginosa populations from CF lungs maintain the same R-pyocin genotype but exhibit heterogeneity in susceptibility to R-pyocins from other strains. Our findings suggest there is likely heterogeneity in response to other types of LPS-binding antimicrobials, such as phage, highlighting the necessity of further studying the potential of LPS-binding antimicrobial particles as alternative therapies in chronic infections.

scholarly journals The Impact of Primer Design on Amplicon-Based Metagenomic Profiling Accuracy: Detailed Insights into Bifidobacterial Community Structure

2020 ◽  
Vol 8 (1) ◽  
pp. 131 ◽  
Author(s):  
Leonardo Mancabelli ◽  
Christian Milani ◽  
Gabriele Andrea Lugli ◽  
Federico Fontana ◽  
Francesca Turroni ◽  
...  
Keyword(s):  
16S Rrna ◽  
16S Rrna Gene ◽  
In Silico ◽  
In Silico Analysis ◽  
Amplification Efficiency ◽  
Rrna Gene ◽  
Test Case ◽  
Bacterial Populations ◽  
Taxonomic Marker ◽  
The Impact

Next Generation Sequencing (NGS) technologies have overcome the limitations of cultivation-dependent approaches and allowed detailed study of bacterial populations that inhabit the human body. The consortium of bacteria residing in the human intestinal tract, also known as the gut microbiota, impacts several physiological processes important for preservation of the health status of the host. The most widespread microbiota profiling method is based on amplification and sequencing of a variable portion of the 16S rRNA gene as a universal taxonomic marker among members of the Bacteria domain. Despite its popularity and obvious advantages, this 16S rRNA gene-based approach comes with some important limitations. In particular, the choice of the primer pair for amplification plays a major role in defining the accuracy of the reconstructed bacterial profiles. In the current study, we performed an in silico PCR using all currently described 16S rRNA gene-targeting primer pairs (PP) in order to assess their efficiency. Our results show that V3, V4, V5, and V6 were the optimal regions on which to design 16S rRNA metagenomic primers. In detail, PP39 (Probio_Uni/Probio_Rev), PP41 (341F/534R), and PP72 (970F/1050R) were the most suitable primer pairs with an amplification efficiency of >98.5%. Furthermore, the Bifidobacterium genus was examined as a test case for accurate evaluation of intra-genus performances at subspecies level. Intriguingly, the in silico analysis revealed that primer pair PP55 (527f/1406r) was unable to amplify the targeted region of any member of this bacterial genus, while several other primer pairs seem to rather inefficiently amplify the target region of the main bifidobacterial taxa. These results highlight that selection of a 16S rRNA gene-based PP should be done with utmost care in order to avoid biases in microbiota profiling results.

scholarly journals Sciadopitys verticillata Resin: Volatile Components and Impact on Plant Pathogenic and Foodborne Bacteria

Molecules ◽  
2019 ◽  
Vol 24 (20) ◽  
pp. 3767
Author(s):  
David I. Yates ◽  
Bonnie H. Ownley ◽  
Nicole Labbé ◽  
Joseph J. Bozell ◽  
William E. Klingeman ◽  
...  
Keyword(s):  
Bacterial Growth ◽  
Foodborne Pathogens ◽  
Antimicrobial Properties ◽  
Principal Component ◽  
Gas Chromatography Mass Spectrometry ◽  
Volatile Components ◽  
Sample Treatment ◽  
Bacterial Populations ◽  
Sciadopitys Verticillata ◽  
The Impact

Sciadopitys verticillata (Sv) produces a white, sticky, latex-like resin with antimicrobial properties. The aims of this research were to evaluate the effects of this resin (Sv resin) on bacterial populations and to determine the impact of its primary volatile components on bioactivity. The impact of sample treatment on chemical composition of Sv resin was analyzed using Fourier transform infrared spectroscopy (FTIR) coupled with principal component analysis. The presence and concentration of volatiles in lyophilized resin were determined using gas chromatography/mass spectrometry (GC/MS). Changes in bacterial population counts due to treatment with resin or its primary volatile components were monitored. Autoclaving of the samples did not affect the FTIR spectra of Sv resin; however, lyophilization altered spectra, mainly in the CH and C=O regions. Three primary bioactive compounds that constituted >90% of volatiles (1R-α-pinene, tricyclene, and β-pinene) were identified in Sv resin. Autoclaved resin impacted bacterial growth. The resin was stimulatory for some plant and foodborne pathogens (Pseudomonas fluorescens, P. syringae, and Xanthomonas perforans) and antimicrobial for others (Escherichia coli, Bacillus cereus, Agrobacterium tumefaciens, and Erwinia amylovora). Treatment with either 1R-α-pinene or β-pinene reduced B. cereus population growth less than did autoclaved resin. The complex resin likely contains additional antimicrobial compounds that act synergistically to inhibit bacterial growth.

scholarly journals In vitrocolonic metabolism of coffee and chlorogenic acid results in selective changes in human faecal microbiota growth

2015 ◽  
Vol 113 (8) ◽  
pp. 1220-1227 ◽  
Author(s):  
Charlotte E. Mills ◽  
Xenofon Tzounis ◽  
Maria-Jose Oruna-Concha ◽  
Don S. Mottram ◽  
Glenn R. Gibson ◽  
...  
Keyword(s):  
Distal Region ◽  
Considerable Proportion ◽  
Faecal Microbiota ◽  
Bacterial Populations ◽  
Beneficial Effects ◽  
Equivalent Quantity ◽  
Fermentation Model ◽  
The Impact ◽  
Preventive Effects

Coffee is a relatively rich source of chlorogenic acids (CGA), which, as other polyphenols, have been postulated to exert preventive effects against CVD and type 2 diabetes. As a considerable proportion of ingested CGA reaches the large intestine, CGA may be capable of exerting beneficial effects in the large gut. Here, we utilise a stirred, anaerobic, pH-controlled, batch culture fermentation model of the distal region of the colon in order to investigate the impact of coffee and CGA on the growth of the human faecal microbiota. Incubation of coffee samples with the human faecal microbiota led to the rapid metabolism of CGA (4 h) and the production of dihydrocaffeic acid and dihydroferulic acid, while caffeine remained unmetabolised. The coffee with the highest levels of CGA (P< 0·05, relative to the other coffees) induced a significant increase in the growth ofBifidobacteriumspp. relative to the control vessel at 10 h after exposure (P< 0·05). Similarly, an equivalent quantity of CGA (80·8 mg, matched with that in high-CGA coffee) induced a significant increase in the growth ofBifidobacteriumspp. (P< 0·05). CGA alone also induced a significant increase in the growth of theClostridium coccoides–Eubacteriumrectalegroup (P< 0·05). This selective metabolism and subsequent amplification of specific bacterial populations could be beneficial to host health.

Effect of Bacteria and Bacterial Constituents on Recovery and Resistance of Tulane Virus

2020 ◽  
Vol 83 (4) ◽  
pp. 661-667
Author(s):  
ADRIENNE E. H. SHEARER ◽  
KALMIA E. KNIEL
Keyword(s):  
Bifidobacterium Bifidum ◽  
Bacterial Populations ◽  
Log Reduction ◽  
Metabolic Products ◽  
Tulane Virus ◽  
Viable Bacteria ◽  
Potential Impact ◽  
The Impact ◽  
Phosphate Buffered Saline ◽  
Bacterial Constituents

ABSTRACT Noroviruses encounter numerous and diverse bacterial populations in the host and environment, but the impact of bacteria on norovirus transmission, infection, detection, and inactivation are not well understood. Tulane virus (TV), a human norovirus surrogate, was exposed to viable bacteria, bacterial metabolic products, and bacterial cell constituents and was evaluated for impact on viral recovery, propagation, and inactivation resistance, respectively. TV was incubated with common soil, intestinal, skin, and phyllosphere bacteria, and unbound viruses were recovered by centrifugation and filtration. TV recovery from various bacterial suspensions was not impeded, which suggests a lack of direct, stable binding between viruses and bacteria. The cell-free supernatant (CFS) of Bifidobacterium bifidum 35914, a bacterium that produces glycan-modifying enzymes, was evaluated for effect on the propagation of TV in LLC-MK2 cells. CFS did not limit TV propagation relative to TV absent of CFS. The impact of Escherichia coli O111:B4 lipopolysaccharide (LPS) and Bacillus subtilis peptidoglycan (PEP) on TV thermal and chlorine inactivation resistance was evaluated. PEP increased TV thermal and chlorine inactivation resistance compared with control TV in phosphate-buffered saline (PBS). TV suspended in PBS and LPS was reduced by more than 3.7 log at 60°C, whereas in PEP, TV reduction was approximately 2 log. Chlorine treatment (200 ppm) rendered TV undetectable (&gt;3-log reduction) in PBS and LPS; however, TV was still detected in PEP, reduced by 2.9 log. Virus inactivation studies and food processing practices should account for potential impact of bacteria on viral resistance.

scholarly journals The Impact of Regeneration and Climate Adaptations of Urban Green–Blue Assets on All-Cause Mortality: A 17-Year Longitudinal Study

2020 ◽  
Vol 17 (12) ◽  
pp. 4577 ◽  
Author(s):  
Zoë Tieges ◽  
Duncan McGregor ◽  
Michail Georgiou ◽  
Niamh Smith ◽  
Josie Saunders ◽  
...  
Keyword(s):  
Health Inequalities ◽  
Positive Impact ◽  
Buffer Zone ◽  
Well Being ◽  
Buffer Zones ◽  
Mitigation And Adaptation ◽  
Urban Waterways ◽  
All Cause Mortality ◽  
The Impact ◽  
Health And Health Inequalities

Urban waterways are underutilised assets, which can provide benefits ranging from climate-change mitigation and adaptation (e.g., reducing flood risks) to promoting health and well-being in urban settings. Indeed, urban waterways provide green and blue spaces, which have increasingly been associated with health benefits. The present observational study used a unique 17-year longitudinal natural experiment of canal regeneration from complete closure and dereliction in North Glasgow in Scotland, U.K. to explore the impact of green and blue canal assets on all-cause mortality as a widely used indicator of general health and health inequalities. Official data on deaths and socioeconomic deprivation for small areas (data zones) for the period 2001–2017 were analysed. Distances between data zone population-weighted centroids to the canal were calculated to create three 500 m distance buffers. Spatiotemporal associations between proximity to the canal and mortality were estimated using linear mixed models, unadjusted and adjusted for small-area measures of deprivation. The results showed an overall decrease in mortality over time (β = −0.032, 95% confidence interval (CI) [−0.046, −0.017]) with a closing of the gap in mortality between less and more affluent areas. The annual rate of decrease in mortality rates was largest in the 0–500 m buffer zone closest to the canal (−3.12%, 95% CI [−4.50, −1.73]), with smaller decreases found in buffer zones further removed from the canal (500–1000 m: −3.01%, 95% CI [−6.52, 0.62]), and 1000–1500 m: −1.23%, 95% CI [−5.01, 2.71]). A similar pattern of results was found following adjustment for deprivation. The findings support the notion that regeneration of disused blue and green assets and climate adaptions can have a positive impact on health and health inequalities. Future studies are now needed using larger samples of individual-level data, including environmental, socioeconomic, and health variables to ascertain which specific elements of regeneration are the most effective in promoting health and health equity.

scholarly journals Colistin and Polymyxin B Dosage Regimens against Acinetobacter baumannii: Differences in Activity and the Emergence of Resistance

2016 ◽  
Vol 60 (7) ◽  
pp. 3921-3933 ◽  
Author(s):  
Soon-Ee Cheah ◽  
Jian Li ◽  
Brian T. Tsuji ◽  
Alan Forrest ◽  
Jürgen B. Bulitta ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Public Health Problem ◽  
Polymyxin B ◽  
Major Public Health Problem ◽  
Bacterial Killing ◽  
Bacterial Populations ◽  
Content Type ◽  
Dosage Regimens ◽  
Drug Concentrations ◽  
The Impact

ABSTRACTInfections caused by multidrug-resistantAcinetobacter baumanniiare a major public health problem, and polymyxins are often the last line of therapy for recalcitrant infections by such isolates. The pharmacokinetics of the two clinically used polymyxins, polymyxin B and colistin, differ considerably, since colistin is administered as an inactive prodrug that undergoes slow conversion to colistin. However, the impact of these substantial pharmacokinetic differences on bacterial killing and resistance emergence is poorly understood. We assessed clinically relevant polymyxin B and colistin dosage regimens against one reference and three clinicalA. baumanniistrains in a dynamic one-compartmentin vitromodel. A new mechanism-based pharmacodynamic model was developed to describe and predict the drug concentrations and viable counts of the total and resistant populations. Rapid attainment of target concentrations was shown to be critical for polymyxin-induced bacterial killing. All polymyxin B regimens achieved peak concentrations of at least 1 mg/liter within 1 h and caused ≥4 log10killing at 1 h. In contrast, the slow rise of colistin concentrations to 3 mg/liter over 48 h resulted in markedly reduced bacterial killing. A significant (4 to 6 log10CFU/ml) amplification of resistant bacterial populations was common to all dosage regimens. The developed mechanism-based model explained the observed bacterial killing, regrowth, and resistance. The model also implicated adaptive polymyxin resistance as a key driver of bacterial regrowth and predicted the amplification of preexisting, highly polymyxin-resistant bacterial populations following polymyxin treatment. Antibiotic combination therapies seem the most promising option for minimizing the emergence of polymyxin resistance.

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