Survival and Growth of Wild-Type and rpoS-Deficient Salmonella Newport Strains in Soil Extracts Prepared with Heat-Treated Poultry Pellets

2019 ◽  
Vol 82 (3) ◽  
pp. 501-506 ◽  
Author(s):  
MANOJ K. SHAH ◽  
RHODEL BRADSHAW ◽  
ESMOND NYARKO ◽  
PATRICIA D. MILLNER ◽  
DEBORAH NEHER ◽  
...  
Keyword(s):  
Wild Type ◽  
Soil Extracts ◽  
Nonsterile Soil ◽  
Unamended Soil ◽  
Salmonella Newport ◽  
Heat Treated ◽  
Maximum Cell ◽  
Survival And Growth ◽  
Cell Densities ◽  
Amended Soil

ABSTRACT Manure runoff can transfer pathogens to farmlands or to water sources, leading to subsequent contamination of produce. Untreated biological soil amendments, like manure, can be contaminated with foodborne pathogens, such as Salmonella Newport, which may lead to transfer of the pathogen to fruits or vegetables. Studies have reported the occurrence and survival of Salmonella in manure or manure slurries. However, data on the survival and growth of Salmonella Newport is lacking in matrices simulating runoff. We quantified the survival and growth of wild-type (WT) Salmonella Newport and rpoS-deficient (ΔrpoS) strains in sterile and nonsterile soil extracts prepared with (amended) or without (unamended) heat-treated poultry pellets at 25°C. Salmonella Newport WT and ΔrpoS populations reached a maximum cell density of 6 to 8 log CFU/mL in 24 to 30 h in amended and unamended soil extracts and remained in stationary phase for up to 4 days. Salmonella Newport in amended soil extracts exhibited a decreased lag phase (λ, 2.87 ± 1.01 h) and greater maximum cell densities (Nmax, 6.84 ± 1.25 CFU/mL) compared with λ (20.10 ± 9.53 h) and Nmax (5.22 ± 0.82 CFU/mL) in unamended soil extracts. In amended soil extract, the ΔrpoS strain had no measurable λ, similar growth rates (μmax) compared with WT, and a lower Nmax compared with the WT strain. Unamended, nonsterile soil extracts did not support the growth of Salmonella Newport WT and led to a decline in populations for the ΔrpoS strain. Salmonella Newport had lower cell densities in nonsterile soil extracts (5.94 ± 0.95 CFU/mL) than it did in sterile soil extracts (6.66 ± 1.50 CFU/mL), potentially indicating competition for nutrients between indigenous microbes and Salmonella Newport. The most favorable growth conditions were provided by amended sterile and nonsterile soil extracts, followed by sterile, unamended soil extracts for both Salmonella Newport strains. Salmonella Newport may grow to greater densities in amended extracts, providing a route for increased Salmonella levels in the growing environments of produce.

Influence of Poultry Litter Amendment Type and Irrigation Events on Survival and Persistence of Salmonella Newport

2020 ◽  
Vol 83 (5) ◽  
pp. 821-828
Author(s):  
JUNE TEICHMANN ◽  
PUSHPINDER KAUR LITT ◽  
MANAN SHARMA ◽  
ESMOND NYARKO ◽  
KALMIA E. KNIEL
Keyword(s):  
Poultry Litter ◽  
Foodborne Pathogen ◽  
Dry Weight ◽  
Soil Samples ◽  
Salmonella Newport ◽  
Heat Treated ◽  
Student’S T ◽  
Raw Poultry ◽  
Determine Moisture Content ◽  
Amended Soil

ABSTRACT Salmonella enterica subsp. enterica serovar Newport is a bacterial foodborne pathogen isolated from several environmental reservoirs on the Delmarva Peninsula and has been associated with several produce-related outbreaks. However, little is known about specific interactions between Salmonella Newport and soil amendments used as fertilizers. The purpose of this study was to determine Salmonella Newport persistence and resuscitation in raw poultry litter (PLR), a common biological soil amendment, and in soils containing poultry litter–based (heat-treated poultry pellets [HTPP]) or chemical fertilizer (urea [U]) amendments to provide equivalent levels of nitrogen to the soil. Inoculated samples were stored in a growth chamber and irrigated regularly over 4 weeks. Soil samples were collected every week for 4 weeks to determine moisture content and surviving Salmonella Newport populations (log CFU per gram dry weight). Data were analyzed by using a one-way analysis of variance and Student's t test. The PLR supported significantly higher (5.07 log CFU/g dry weight [gdw]) populations of Salmonella Newport than HTPP only (1.70 log CFU/gdw). However, PLR-amended (PLRA) soil (2.5 log CFU/gdw) samples had significantly (P < 0.05) lower Salmonella Newport populations compared with HTPP-amended (4.5 log CFU/gdw) and U-amended (4.0 log CFU/gdw) soil samples. The effect of irrigation on Salmonella Newport population levels in PLRA soils was significant, and in a comparative study, the overall increase in the pathogen levels in U-amended soil (mean = 1.12 log CFU/gdw) was significantly greater than that in PLRA soil (mean = 0.54 log CFU/gdw), whereas that in HTPP-amended soil (0.80 log CFU/gdw) was not significantly different from PLRA soil. HIGHLIGHTS

scholarly journals Rethinking Manure Application: Increase in Multidrug-Resistant Enterococcus spp. in Agricultural Soil Following Chicken Litter Application

2021 ◽  
Vol 9 (5) ◽  
pp. 885
Author(s):  
Dorcas Oladayo Fatoba ◽  
Akebe Luther King Abia ◽  
Daniel G. Amoako ◽  
Sabiha Y. Essack
Keyword(s):  
Antimicrobial Resistance ◽  
Agricultural Soil ◽  
Multidrug Resistant ◽  
Diffusion Method ◽  
Resistant Bacteria ◽  
Manure Application ◽  
Unamended Soil ◽  
Enterococcus Spp ◽  
Chicken Litter ◽  
Amended Soil

The current study investigated the impact of chicken litter application on the abundance of multidrug-resistant Enterococcus spp. in agricultural soil. Soil samples were collected from five different strategic places on a sugarcane farm before and after manure application for four months. Chicken litter samples were also collected. Enterococci were enumerated using the Enterolert®/Quanti-Tray 2000® system and confirm and differentiated into species using real-time PCR. The antibiotic susceptibility profile of the isolates was determined using the disk diffusion method following the European Committee on Antimicrobial Susceptibility Testing (EUCAST) guidelines. The overall mean bacterial count was significantly higher (p < 0.05) in manure-amended soil (3.87 × 107 MPN/g) than unamended soil (2.89 × 107 MPN/g). Eight hundred and thirty-five enterococci (680 from soil and 155 from litter) were isolated, with E. casseliflavus being the most prevalent species (469; 56.2%) and E. gallinarum being the least (16; 1.2%). Approximately 56% of all the isolates were resistant to at least one antibiotic tested, with the highest resistance observed against tetracycline (33%) and the lowest against chloramphenicol (0.1%); 17% of E. faecium were resistant to quinupristin-dalfopristin. Additionally, 27.9% (130/466) of the isolates were multidrug-resistant, with litter-amended soil harbouring more multidrug-resistant (MDR) isolates (67.7%; 88/130) than unamended soil (10.0%; 13/130). All isolates were susceptible to tigecycline, linezolid and gentamicin. About 7% of the isolates had a multiple antimicrobial resistance index > 0.2, indicative of high antibiotic exposure. Although organic fertilizers are regarded as eco-friendly compared to chemical fertilizers for improving soil fertility, the application of untreated animal manure could promote the accumulation of antibiotics and their residues and antibiotic-resistant bacteria in the soil, creating an environmental reservoir of antimicrobial resistance, with potential human and environmental health risks.

Land-fast ice microalgal and phytoplanktonic communities (Adélie Land, Antarctica) in relation to environmental factors during ice break-up

2003 ◽  
Vol 15 (3) ◽  
pp. 353-364 ◽  
Author(s):  
C. RIAUX-GOBIN ◽  
M. POULIN ◽  
R. PRODON ◽  
P. TREGUER
Keyword(s):  
Sea Ice ◽  
Early Spring ◽  
Ice Melt ◽  
Fast Ice ◽  
Maximum Cell ◽  
Cell Densities ◽  
Ice Water ◽  
Water Species ◽  
Very High ◽  
Pennate Diatoms

Annual land-fast ice, particularly an unconsolidated layer or “platelet ice-like” layer (PLI), was sampled in spring 1995 to study the spatial and short-term variations of ice-associated diatoms. Under-ice water, a lead and small polynyas were also sampled. Along a 7 km seaward transect a geographical gradient was evident, with some rare diatom species present only in the offshore PLI, whereas others (mainly pennate diatoms) were ubiquitous. The dense microphytic PLI community as well as the phytoplankton was diatom-dominated, but, within these two communities, marked differences appeared. First, the sea-ice communities (PLI and solid bottom ice) were moderately diverse (36 species), mostly composed of pennate diatoms, of which many were chain forming or tube-dwelling. Dominant taxa were Navicula glaciei, Berkeleya adeliensis, Nitzschia stellata, Amphiprora kufferathii and Nitzschia lecointei. Some differences in the distribution of the most dominant species appeared within the bottom ice and the PLI, attesting to differences in the origin or/and growing capability of these diatoms in these two ice compartments. Under-ice water species composition was mixed with sea-ice communities only on the most coastal sites and during ice melt. Maximum cell numbers were mostly noticed in the PLI, reaching up to 1010 cells l−1 and very high Chl a concentrations (exceptionally up to 9.8 mg Chl a l−1 or 1.9 g Chl a m−2, from a 10 to 20 cm thick PLI layer, close to the continent). Secondly, the phytoplankton in the lead and small polynyas had a low diversity, very low standing stocks (on an average 0.69 μg Chl a l−1) and cell densities (2 × 104 cells l−1). Some species from the polynyas were similar to those of the PLI, such as Navicula glaciei, but others were typically planktonic, such as Chaetoceros cf. neglectus. The presence of encysted cells (Chaetoceros and Chrysophytes) was also noticeable in the polynya water. In early spring no seeding process was obvious from the PLI to polynya water. A comparison with similar fast-ice diatom communities in other parts of coastal Antarctica, is presented.

scholarly journals Effects of Gypsum on Zoospores and Sporangia of Phytophthora cinnamomi in Field Soil

Plant Disease ◽  
2000 ◽  
Vol 84 (6) ◽  
pp. 617-621 ◽  
Author(s):  
B. J. Messenger ◽  
J. A. Menge ◽  
E. Pond
Keyword(s):  
Calcium Sulfate ◽  
Phytophthora Cinnamomi ◽  
Calcium Nitrate ◽  
Passive Movement ◽  
Field Soil ◽  
Soil Extracts ◽  
Zoospore Production ◽  
Colony Forming Units ◽  
Amended Soil

Sporangial production of Phytophthora cinnamomi buried in gypsum-amended avocado soil for 2 days was reduced by as much as 74% in greenhouse trials. P. cinnamomi sporangial volume was reduced an average of 64% in gypsum-amended soil. Soil extracts from gypsum-amended soil reduced in vitro sporangial production and volume. Irrigation with gypsum solutions of buried mycelium in unamended soil also reduced sporangial production and volume. Zoospore production and colony-forming units of P. cinnamomi were reduced in soil amended with calcium sulfate, calcium nitrate, or calcium carbonate. Zoospore encystment or passive movement through soil was not significantly affected by gypsum soil amendments.

Incidence, Radioresistance, and Behavior of Psychrobacter spp. in Rabbit Meat

2005 ◽  
Vol 68 (3) ◽  
pp. 538-543 ◽  
Author(s):  
JOSÉ M. RODRÍGUEZ-CALLEJA ◽  
MARGARET F. PATTERSON ◽  
ISABEL GARCÍA-LÓPEZ ◽  
JESÚS A. SANTOS ◽  
ANDRÉS OTERO ◽  
...  
Keyword(s):  
Similar Increase ◽  
Chilled Storage ◽  
Relative Incidence ◽  
Spoilage Bacteria ◽  
Brochothrix Thermosphacta ◽  
Pure Cultures ◽  
Maximum Cell ◽  
Rabbit Meat ◽  
Cell Densities ◽  
And Behavior

The relative incidence of Psychrobacter spp. in rabbit meat, the radioresistance of these bacteria, and the growth of nonirradiated and irradiated psychrobacter isolates, alone and in coculture, during chilled storage of inoculated sterile rabbit meat was investigated. Psychrobacter spp. accounted for 4.2% of the storage psychrotrophic flora of 30 rabbit carcasses. The radiation D10-values of 10 Psychrobacter isolates, irradiated at 4°C in minced rabbit meat, ranged from 0.8 to 2.0 kGy, with significant (P &lt; 0.05) differences among strains. Over 12 days of storage at 4°C, pure cultures of two nonirradiated psychrobacter strains (D10 = 2 kGy) were capable of substantial increases (up to 3 log CFU/g) in sterile rabbit meat, but when the fastest growing strain was cocultured with Pseudomonas fluorescens and Brochothrix thermosphacta isolates, maximum cell densities and growth rates were significantly (P &lt; 0.01) lower. After irradiation (2.5 kGy) of pure cultures in sterile rabbit meat, surviving cells of both Psychrobacter strains decreased for a period of 5 to 7 days and then resumed multiplication that, at day 12, resulted in a similar increase (1.6 to 1.7 log CFU/g) over initial survivor numbers. When irradiated in combination with the spoilage bacteria, one of the strains required 12 days to reach initial numbers. In conclusion, Psychrobacter spp. are radioresistant nonsporeforming bacteria with a low relative incidence among the storage flora of rabbit meat, unable to compete with food spoilage bacteria in this ecosystem and apparently not a major contributor to the spoilage of rabbit meat after irradiation.

Growth of Listeria spp. in Shredded Cabbage Is Enhanced by a Mild Heat Treatment

2010 ◽  
Vol 73 (3) ◽  
pp. 425-433 ◽  
Author(s):  
TIMOTHY C. ELLS ◽  
LISBETH TRUELSTRUP HANSEN
Keyword(s):  
Thermal Processing ◽  
Fruits And Vegetables ◽  
Storage Period ◽  
Thermal Treatments ◽  
Organoleptic Properties ◽  
Maximum Increase ◽  
Safety Issues ◽  
Heat Treated ◽  
Survival And Growth ◽  
Growth Inhibiting

Mild thermal processing can enhance the shelf life of cut fruits and vegetables by delaying the onset of spoilage and preserving the organoleptic properties of shredded cabbage. However, food safety issues related to this process have not been fully investigated. Therefore, the survival and growth of Listeria spp. on cabbage treated in this manner was examined. Experimentally, 24 strains of Listeria spp. (including L. monocytogenes) were inoculated onto cut and intact cabbage tissues and stored at 5°C. All strains on intact tissues exhibited a moderate decline in numbers (up to 1.0 log CFU/cm2) over the 28-day storage period. Conversely, cut tissue supported growth of most strains during the first 7 to 14 days of incubation with maximum increases of 1.2 log CFU/cm2. Subsequently, the survival or growth on heat-treated (50°C for 3 min) and untreated shredded cabbage of four L. monocytogenes and four nonpathogenic Listeria spp. strains were compared during storage for 21 days at 5°C. Growth on untreated shred for all strains was similar to the results observed on cut tissue with a maximum increase of approximately 1.0 log CFU/g. However, in the heat-treated cabbage shred all strains displayed a rapid increase in growth (up to 2.5 log CFU/g) during the first 7 days of incubation, which may be indicative of the destruction of an endogenous growth-inhibiting compound within the cabbage. In conclusion, this study shows that mild thermal treatments of cut cabbage may promote pathogen growth if other inimical barriers are not implemented downstream of the thermal treatment.

Effects of bacterial lignin peroxidase on organic carbon mineralization in soil, using recombinant Streptomyces strains

1991 ◽  
Vol 37 (4) ◽  
pp. 287-294 ◽  
Author(s):  
Zemin Wang ◽  
Don L. Crawford ◽  
Timothy S. Magnuson ◽  
Bruce H. Bleakley ◽  
Greg Hertel
Keyword(s):  
Organic Carbon ◽  
Lignin Peroxidase ◽  
Turnover Rate ◽  
Carbon Mineralization ◽  
Evolution Rate ◽  
Carbon Turnover ◽  
Wild Type ◽  
Sterile Soil ◽  
Short Term ◽  
Nonsterile Soil

To study the effects of bacterial lignin peroxidase ALip-P3 of Streptomyces viridosporus T7A on the rate of organic carbon turnover in soil, purified lignin peroxidase, with and without addition of H2O2, was added to sterile and nonsterile silt loam soil. Recombinant Streptomyces lividans strains expressing plasmid-encoded ALip-P3 were also inoculated into the soil. Carbon mineralization was monitored by measuring the rate of CO2 evolution from the soil. In sterile soil, lignin peroxidase addition altered carbon turnover, by increasing the CO2 evolution rate above the near-zero rate of sterile, uninoculated soil. H2O2, when added alone, had no effect, and its addition in combination with peroxidase gave results similar to peroxidase alone. This effect was also observed upon addition of lignin peroxidase to sterile soil already inoculated with S. viridosporus T7A. The increases in soil CO2 evolution rates were also observed in experiments using nonsterile soil. However, results showed more variation, and the effect was shorter lived as a result of lessened peroxidase stability. Three recombinant S. lividans strains expressing the ALip-P3 gene in plasmid pIJ702.LP were also inoculated into soil. There were no significant differences in CO2 evolution rates for sterile soil inoculated with recombinants as compared with sterile soil inoculated with wild-type S. lividans strains. However, in nonsterile soil, addition of the recombinants caused a significantly greater increase in the CO2 evolution rate as compared with the corresponding wild types or S. viridosporus T7A. The effect was short lived, lasting about 5 days. Both the recombinant and wild-type Streptomyces survived in the soil for at least 30 days, and pIJ702.LP was stable in the recombinants in soil. Plasmid pIJ702.LP was transformed into three mutants of S. viridosporus T7A that lacked lignin peroxidase. Plasmid-expressing transformants regained the ability to produce lignin peroxidase. The results show that addition of lignin peroxidase ALip-P3 to soil transiently enhanced the short-term rate of carbon mineralization in the soil. The enhancement was lignin peroxidase specific, since substitution of horseradish peroxidase for lignin peroxidase in the soil addition studies resulted in no enhancement of CO2 evolution. In addition, pIJ702.LP-expressing S. lividans strains also caused the effect, which was significant only in nonsterile soil. Thus, lignin peroxidase ALip-P3 appears to affect the short-term turnover rate of lignin-derived organic carbon in soil, and normal, low lignin peroxidase concentrations in soil may limit the initial turnover rate of lignified plant residues in soil. This is the first report of a genetically engineered microorganism having a measurable effect on a biogeochemical cycle in soil. Key words: Streptomyces, recombinant, lignin, peroxidase, soil.

scholarly journals Sociality in Escherichia coli: Enterochelin Is a Private Good at Low Cell Density and Can Be Shared at High Cell Density

2015 ◽  
Vol 197 (13) ◽  
pp. 2122-2128 ◽  
Author(s):  
Rebecca L. Scholz ◽  
E. Peter Greenberg
Keyword(s):  
Escherichia Coli ◽  
Cell Density ◽  
Iron Acquisition ◽  
Partial Privatization ◽  
High Cell ◽  
Wild Type ◽  
Content Type ◽  
Cell Densities ◽  
The Cost ◽  
Low Cell Density

ABSTRACTMany bacteria produce secreted iron chelators called siderophores, which can be shared among cells with specific siderophore uptake systems regardless of whether the cell produces siderophores. Sharing secreted products allows freeloading, where individuals use resources without bearing the cost of production. Here we show that theEscherichia colisiderophore enterochelin is not evenly shared between producers and nonproducers. Wild-typeEscherichia coligrows well in low-iron minimal medium, and an isogenic enterochelin synthesis mutant (ΔentF) grows very poorly. The enterochelin mutant grows well in low-iron medium supplemented with enterochelin. At high cell densities the ΔentFmutant can compete equally with the wild type in low-iron medium. At low cell densities the ΔentFmutant cannot compete. Furthermore, the growth rate of the wild type is unaffected by cell density. The wild type grows well in low-iron medium even at very low starting densities. Our experiments support a model where at least some enterochelin remains associated with the cells that produce it, and the cell-associated enterochelin enables iron acquisition even at very low cell density. Enterochelin that is not retained by producing cells at low density is lost to dilution. At high cell densities, cell-free enterochelin can accumulate and be shared by all cells in the group. Partial privatization is a solution to the problem of iron acquisition in low-iron, low-cell-density habitats. Cell-free enterochelin allows for iron scavenging at a distance at higher population densities. Our findings shed light on the conditions under which freeloaders might benefit from enterochelin uptake systems.IMPORTANCESociality in microbes has become a topic of great interest. One facet of sociality is the sharing of secreted products, such as the iron-scavenging siderophores. We present evidence that theEscherichia colisiderophore enterochelin is relatively inexpensive to produce and is partially privatized such that it can be efficiently shared only at high producer cell densities. At low cell densities, cell-free enterochelin is scarce and only enterochelin producers are able to grow in low-iron medium. Because freely shared products can be exploited by freeloaders, this partial privatization may help explain how enterochelin production is stabilized inE. coliand may provide insight into when enterochelin is available for freeloaders.

scholarly journals Coniothyrium minitans survival in soil and ability to infect sclerotia of Sclerotinia sclerotiorum

2011 ◽  
Vol 64 ◽  
pp. 168-174 ◽  
Author(s):  
E.E. Jones ◽  
A. Stewart
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Solid Substrate ◽  
Spore Suspension ◽  
Hygromycin B ◽  
Wild Type ◽  
Coniothyrium Minitans ◽  
Soil Population ◽  
Unambiguous Detection ◽  
Amended Soil

Survival of the sclerotial parasite Coniothyrium minitans in soil when applied as spore suspension or colonised solid substrate (maizemealperlite) inocula and ability to infect Sclerotinia sclerotiorum sclerotia incorporated into the soil after different times was assessed over 6 months Unambiguous detection of the C minitans isolate from the indigenous C minitans soil population was achieved using a hygromycin B resistant transformant (T3) which was similar in behaviour to the wild type LU112 Coniothyrium minitans was recovered from soil by dilution plating at all assessment times with higher recovery from spore suspension compared with maizemealperlite amended soil Coniothyrium minitans was able to infect and reduce viability of sclerotia incorporated into the amended soil over the 6 month experiment with spore suspension significantly increasing infection compared with maizemealperlite inoculum Hygromycin B amendment of the agar significantly increased C minitans recovery from sclerotia especially when the population of secondary fungal colonisers was high

scholarly journals Mapping the Fundamental Niches of Two Freshwater Microalgae,Chlorella vulgaris(Trebouxiophyceae) andPeridinium cinctum(Dinophyceae), in 5-Dimensional Ion Space

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
Terence J. Evens ◽  
Randall P. Niedz
Keyword(s):  
Growth Rate ◽  
Experimental Design ◽  
Chlorella Vulgaris ◽  
Growth Rates ◽  
Ion Concentration ◽  
Freshwater Microalgae ◽  
Batch Cultures ◽  
Fundamental Niche ◽  
Maximum Cell ◽  
Cell Densities

The fundamental niche defined by five ions,NO3 −,PO4 3−, K+, Na+, andCl−, was mapped forChlorella vulgaris(Trebouxiophyceae) andPeridinium cinctum(Dinophyceae) growth rates and maximum cell densities in batch cultures. A five dimensional ion-mixture experimental design was projected across a total ion concentration gradient of 1 to 30 mM to delineate the ion-based, “potential” niche space, defined as the entiren-dimensional hypervolume demarcated by the feasible ranges of the independent factors under consideration. The growth rate-based, fundamental niche volumes overlapped for ca. 94% of the ion mixtures, although the regions of maximal growth rates and cell densities were different for each alga. BothC. vulgarisandP. cinctumexhibited similar positive responses to cations and negative responses to anions. It was determined that total ion concentration for these five ions, from 1 to 30 mM, did not directly affect either growth rate or maximal cell density for either alga, although it did play an interactive role with several ions. This study is the first that we are aware of to attempt the mapping of a multivariate, ion-based, fundamental niche volume. The implications of the experimental design utilized and the potential utility of this type of approach are discussed.

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