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At least 19 recordsLinked to original sources
PubMed2006

Simultaneous detection by PCR of Escherichia coli, Listeria monocytogenes and Salmonella typhimurium in artificially inoculated wheat grain.

A multiplex PCR procedure was established to detect Escherichia coli, Listeria monocytogenes and Salmonella typhimurium in artificially inoculated wheat grain. The PCR protocol with an enrichment step successfully detected all three organisms inoculated together in non-autoclaved wheat grain. After a one day enrichment, E. coli, L. monocytogenes and S. typhimurium were detected at levels of 56, 1800 and <54 CFU/mL, respectively, in the initial sample. For L. monocytogenes, an improved detection limit of <62 CFU/mL was achieved using singleplex PCR. For autoclaved wheat grain inoculated with the three bacterial strains individually, a detection limit of 3 CFU/mL was achieved after an enrichment step. The ability to test for the three bacteria simultaneously will save time and increase the ability to assure grain quality.

Animals↗
PubMed2005

Molecular detection of BHV-1 in artificially inoculated semen and in the semen of a latently infected bull treated with dexamethasone.

Two polymerase chain reaction (PCR) assays specific for glycoprotein B (gB) and glycoprotein E (gE) gene detection, respectively, were adopted for the detection of bovine herpesvirus-1 (BHV-1) in naturally infected bulls. The methods were tested on bovine semen artificially inoculated with BHV-1 and were compared with an optimised virus isolation method. Raw and extended semen samples were diluted in minimal essential medium (MEM) and spiked with equal dose of BHV-1. The extended semen was found to be more toxic for the cells than the raw semen, while the viral DNA could be detected by the PCR method in all tested dilutions of raw and extended semen samples. The sensitivity of both methods was compared also for BHV-1 detection in semen, nasal swabs and leucocytes of a seropositive bull in a different time period after virus reactivation with dexamethasone treatment. The sensitivity of virus detection by the PCR method was equivalent to that of virus isolation in cell culture. However, PCR was shown to be faster and easier to perform and may be a good alternative to virus isolation especially when bovine semen has to be screened for BHV-1 prior to artificial insemination.

Animals↗
PubMed1998

Survival and growth of Campylobacter jejuni after artificial inoculation onto chicken skin as a function of temperature and packaging conditions.

Campylobacter jejuni is one of the major causes of food poisoning in humans. C. jejuni is also widespread in food animals, and meat and meat products derived from food animals are the most common vector of bacterial transmission to humans. To determine the role of packing and storage conditions on the replication of C. jejuni on chicken, the virulent strain C. jejuni 81116 was artificially inoculated onto chicken skin pieces (1 cm2) and stored at different temperatures and under various packaging conditions. C. jejuni 81116 remained viable at -20 and -70 degrees C and was able to replicate at 4 degrees C and at ambient room temperature. C. jejuni 81116 was also inoculated onto chicken skin and subjected to repeated freeze thawing and the viability of the inoculum was quantified. C. jejuni 81116 could withstand repeated freeze thawing similar to that which may occur in the domestic home. Under all freezing conditions, C. jejuni 81116 retained a high level of viability and quickly replicated to levels which exceeded Australian food authorities' permitted bacteria level on raw food products after the sample was thawed.

Animals↗
PubMed2001

Climatic effects on Salmonella survival in plant and soil irrigated with artificially inoculated wastewater: preliminary results.

The use of wastewater to replace other water resources for irrigation is highly dependent on whether the health risk and environmental impacts entailed are acceptable or not. Total count and species of microorganisms found in wastewater vary widely because of climatic conditions, season, population sanitary habits and disease incidence. Salmonella, one of the genera associated with waterborne diseases, lives in the intestine. Thus, it is widely accepted that they have a limited survival period under environmental conditions. Wastewater management practices and the ability of Salmonella to survival under field conditions would determine the health risk associated with its presence in wastewater. Although chlorination is widely used, there are situations in which Salmonella is able to survive the sudden stress imposed by this technique. The aim of this experiment was to contribute to the study of the climatic and soil effects on pathogen survival under agricultural field conditions in order to assess which were the best wastewater management practices from both health and economic points of view. Five pots filled with soil seeded with Medicago sativa and an automatic weather station were used. A secondary effluent was artificially inoculated with Salmonella. In addition, open plates (filled with sterilised soil) and ultraviolet radiation isolated plates (filled with non-sterilised soil) were used. As soil heat emission contributes to the environmental conditions around the bacteria, standardised meteorological temperature data had to be carefully used in the bacterial survival studies under agricultural conditions. Radiation was the main cause of Salmonella mortality as its effect was more important than natural soil bacteria competence. Higher reduction of Salmonella counts could have been associated with longer spring days. Soil was able to effectively remove Salmonella. Subsurface drip irrigation methods could provide an effective tool to prevent health risk associated with wastewater irrigation.

Agriculture↗
PubMedDate not supplied

Polymerase chain reaction (PCR) for the detection of Salmonella in artificially inoculated chicken meat.

The aim of this study was to develop a polymerase chain reaction (PCR) protocol for the detection of Salmonella in artificially contaminated chicken meat. Tests were performed with different dilutions of Salmonella Typhimurium or Salmonella Enteritidis cells (10(-7), 10(-8) or 10(-9) CFU/mL) inoculated in chicken meat samples, in order to establish the limits of detection, incubation times (0, 6, 8 and 24 hours of pre-enrichment in PBW 1%) and three DNA extraction protocols (phenol-chloroform, thermal treatment and thermal treatment and Sephaglass). The assay was able to detect until 10(-9) CFU/mL of initial dilution of Salmonella cells inoculated in chicken meat, which allows detection of Salmonella within 48 hours, including 24 hours of pre-enrichment and using the phenol-chloroform DNA extraction protocol. As the results are obtained in a shorter time period than that of microbiological culture, this procedure will be useful in the methodology for detection of Salmonella in chicken.

Animals↗
PubMed1988

Therapy of Aujeszky's disease (pseudorabies) in naturally infected and artificially inoculated piglets using BW B759U (9-[1,3-dihydroxy-2-propoxymethyl] guanine).

Two experimental porcine models of Aujeszky's disease (AD) were compared for assessing the efficacy of potential antiviral compounds. While signs were the same following intranasal inoculation and in-contact transmission of the causal herpesvirus, SHV-1 (Suid herpesvirus), the time-course of the disease was different. There was less variation in clinical signs between pigs following artificial infection, but the disease was more severe, making this a consistent but also more stringent test system. A nucleoside analogue, BW B759U (9-[1,3-dihydroxy-2-propoxy-methyl] guanine), was administered intramuscularly in divided twice daily doses at 50 mg kg-1 to three-week-old piglets in these two SHV-1 disease models. In artificially infected animals, in which treatment was begun 1.5 hours preinfection and continued for six days, there was a delay in the onset of clinical signs (4.8 compared with 3.2 days), a 1 log10 reduction in virus shedding, and a 1 to 2 log10 reduction in virus recovered from tissues, but all the treated piglets died from AD. In contrast, none of the BW B759U-treated piglets in the in-contact model system died during the eight-day medication period, although two piglets died subsequently. Mean serum concentrations of BW B759U two hours after intramuscular dosing were about 45 microM, at nine hours 15 to 20 microM and at 17 hours 3.5 microM. The in vitro IC50 of BW B759U against SHV-1 varies from 1.5 to 80 microM depending on the cell line in which the assay is carried out. There were no overt signs of BW B759U toxicity in the treated piglets.

Acyclovir↗
PubMed2001

Detection of Xanthomonas oryzae pv. oryzae in artificially inoculated and naturally infected rice seeds and plants by molecular techniques.

A polymerase chain reaction (PCR) technique was developed for detecting the presence of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight (BLB) pathogen in rice seed and for studying the transmission of this bacterium from seed to plant. Primers TXT and TXT4R from an insertion sequence (IS1113) of the pathogen were used to amplify a 964-bp DNA fragment. A combined biological and enzymatic amplification (BIO-PCR) technique was used to detect the pathogen in naturally infected seed. The level of detection of TXT and TXT4R primers was 55 fg DNA of X. o. pv. oryzae, which is roughly the equivalent of seven cells (and four cells in pure culture suspension) of X. o. pv. oryzae. Hybridization of IS1113 with the amplified DNA fragment in Southern blot analysis confirmed that the 964-bp DNA fragment was amplified from X. o. pv. oryzae. The presence of the IS1113 element in strains of X. o. pv. oryzae from 16 rice-growing countries was confirmed by DNA dot blot analysis. X. o. pv. oryzae was detected from the seed washes and DNA extracted from the seed washes of naturally infected seeds of cvs Jaya and TN1. When stored at 4 degrees C, the pathogen was recovered up to 4 months and 9 months from naturally infected seeds of cvs Jaya and TN1, respectively. The BLB bacterium was also detected in seedlings, mature plants and seeds collected from plants raised from naturally infected seeds.

Blotting, Southern↗
PubMed2004

Survival and injury of Arcobacter after artificial inoculation into drinking water.

The aim of this work was to assess the effect of chlorine water treatment on Arcobacter butzleri and to study the survival strategies of this organism in chlorinated and non-chlorinated drinking water. A. butzleri NCTC 12481 was inoculated into chlorinated and non-chlorinated water and samples were removed aseptically, immediately and periodically during the next 2 days (for chlorinated drinking water) or 35 days (for non-chlorinated drinking water). The membrane integrity (Live/Dead BacLight kit), 16S rRNA (FISH technique), DNA content (23S rRNA PCR-RFLPs) and culturability changes in A. butzleri cells were analyzed. Culturability of the cells was lost at 5 min in chlorinated drinking water. At that time the cells showed membrane damage, although fluorescent intensity of 16S rRNA hybridization was constant throughout the chlorine treatment. After 48 h the amplicon specific for the 23S rRNA gene was weakly detected. In non-chlorinated drinking water cells lost their culturability after 16 days but the other factors measured indicated that Arcobacter remained viable throughout the experiment.

Arcobacter↗
PubMed1990

[Occurrence of Fusarium strains and their mycotoxins in corn silage. 7. Formation of deoxynivalenol (DON) in a silage corn plot artificially inoculated with Fusarium culmorum and the effect of silaging on the stability of the DON formed].

The formation of deoxynivalenol in a maize plot inoculated with Fusarium culmorum was studied over a growing season. Already three weeks after inoculation 4.9 mg/kg of DON were measured in the infected ears. The toxin concentration increased continuously up to harvest after eight weeks to a value of 261 mg/kg. Ensilage experiments in laboratory scale silos have shown that the DON content of naturally contaminated corn-cob-mix was not reduced during the ensilage process. It was concluded that infection of maize plants by toxin-producing Fusarium species followed by DON production in the field seems to be the most probable way of contamination of maize silage with this mycotoxin.

Animals↗
PubMed2004

Comparative evaluation of the new version of the INNO-LiPA Mycobacteria and genotype Mycobacterium assays for identification of Mycobacterium species from MB/BacT liquid cultures artificially inoculated with Mycobacterial strains.

The performance of two DNA line probe assays, a new version of INNO-LiPA Mycobacteria (Innogenetics, Ghent, Belgium) and the GenoType Mycobacterium (Hain Diagnostika, Nehren, Germany), were evaluated for identification of mycobacterial species isolated from liquid cultures. Both tests are based on a PCR technique and designed for simultaneous identification of different mycobacterial species by reverse hybridization and line probe technology. The INNO-LiPA Mycobacteria v2 targeting the 16S-23S rRNA gene spacer region was developed for the simultaneous identification of 16 different mycobacterial species. The GenoType Mycobacterium, which targets the 23S rRNA gene, allows simultaneous identification of 13 mycobacterial species. Both tests were evaluated on 110 mycobacterial strains belonging to 22 different mycobacterial species (20 reference strains, 83 clinical strains, and 4 Mycobacterium kansasii strains isolated from tap water) that were previously inoculated into MB/BacT bottles. The sensitivity of both methods, defined as the number of positive results obtained with the Mycobacterium genus probe together with an interpretable result on the number of samples tested was 110 of 110 (100%) for INNO-LiPA and 102 of 110 (92.7%) for GenoType. For samples with interpretable results, INNO-LiPA was able to correctly identify 109 of 110 samples (99.1%), whereas the GenoType correctly identified 100 of 102 samples (98.0%). Both tests were easy to perform, rapid, and reliable when applied to mycobacterial identification directly from MB/BacT bottles.

DNA, Ribosomal Spacer↗
PubMed1992

The effect of air scrubbing on moisture pickup, aerobic plate counts, Enterobacteriaceae, and the incidence of salmonellae on artificially inoculated broiler carcasses.

Processed broiler carcasses were subjected to diffused air at 158.6 kPa (air scrubbing) in tap water to evaluate the potential of this treatment for improving the microbiological quality of read-to-cook poultry. Carcasses were inoculated with a marker strain of Salmonella typhimurium 5 min before treatment. The carcasses were removed after 30 min and sampled for aerobic plate counts (APC), Enterobacteriaceae (ENT) counts, for the presence of the marker organism, or for moisture pickup. The S. typhimurium were recovered from 32 of 40 control carcasses (water only), but from only 9 of 40 air-scrubbed samples. When carcasses were inoculated with fewer than 150 cells of the marker organism, air scrubbing was more effective in reducing the incidence of salmonellae (2 of 20 positive) than when levels were in excess of 150 cells (7 of 20 positive). A similar pattern was manifested with the water-rinsed carcasses rinsed without air injection (below 150, 12 of 20; above 150, 20 of 20). No significant differences were found in the APC and ENT counts. Moisture pickup was adversely affected by air scrubbing; control carcasses had a moisture pickup of 5.8%, whereas, air-scrubbed carcasses had a moisture pickup of 13.9%.

Analysis of Variance↗
PubMed2001

Efficacy of washing with a commercial flatbed brush washer, using conventional and experimental washing agents, in reducing populations of Escherichia coli on artificially inoculated apples.

Conventional and experimental washing formulations were applied with a commercial flatbed brush washer under conditions representative of commercial practice to determine their efficacy in decontaminating apples inoculated with a nonpathogenic Escherichia coli strain. Golden Delicious apples (18 kg) inoculated with E. coli were mixed with approximately 109 kg of uninoculated Fuji apples (distinctly different in appearance) in a wet dump tank containing 1,325 liters of water at 20 degrees C for 15 min. The combined apples were washed in a flatbed brush washer with the following washing solutions: water at 20 degrees C, water at 50 degrees C, 200 ppm of chlorine (pH 6.4) at 20 degrees C, 8% trisodium phosphate at 20 degrees C, 8% trisodium phosphate at 50 degrees C, 5% hydrogen peroxide at 20 degrees C, 5% hydrogen peroxide at 50 degrees C, 1% APL Kleen 245 at 50 degrees C, and two-stage washing treatments using the combination of 1% APL Kleen 245 at 20 or 50 degrees C followed by 5% hydrogen peroxide at 35 or 50 degrees C. None of the washing treatments tested under the conditions of this experiment significantly reduced the E. coli populations on the inoculated apples or in cider made from these apples, probably as a consequence of the inability of this washing system to inactivate or remove the bacterial cells in inaccessible calyx and stem areas of apples. These results are important because they demonstrate the need for new fruit washing technology that can overcome this limitation. Also, there was no significant cross-contamination of the Fuji apples in the dump tank. Significant cross-contamination of cider, made with uninoculated apples, occurred in the hammer mill and/or the press cloth when these units were not sanitized following a trial with inoculated apples.

Colony Count, Microbial↗
PubMed2002

Gas formation in ground beef chubs due to Hafnia alvei is reduced by multiple applications of antimicrobial interventions to artificially inoculated beef trim stock.

Gas-forming microorganisms were isolated from gas-swollen ground beef chubs obtained from a commercial source and were phenotypically identified as Hafnia alvei. In in situ experiments, the isolated H. alvei strains produced gas in inoculated irradiation-sterilized ground beef chubs. A five-strain cocktail of H. alvei isolates was inoculated on beef trim. The inoculated beef trim samples were treated with either a water wash (W) at 65 psi for five passes (a pass refers to the application of successive multiple antimicrobial treatments to inoculated beef trim on a moving processing conveyor belt at a speed of 1 cm/s under heat ducts or oscillating spray nozzles), W plus a 2% (vol/vol) lactic acid wash (L) at room temperature at 30 psi for three passes (W/L), or a combination treatment (COMB) consisting of W plus 82 degrees C water for three passes plus 510 degrees C hot air for six passes plus L, or were not treated (control). After treatment, the beef trim was ground and vacuum packaged. The numbers of H. alvei were reduced with water alone and with the aforementioned antimicrobial intervention treatments. For the untreated and inoculated control samples, the numbers of H. alvei increased from 7.03 to 8.40 log CFU/g after 7 days of incubation at 4 degrees C. However, the numbers of H. alvei treated by successive antimicrobial interventions (COMB) were initially reduced to 5.25 log CFU/g and increased to just 6.9 log CFU/g after 7 days of incubation at 4 degrees C. Gas was produced in untreated control samples after 3 days at 15 degrees C (15 of 15 inoculated chubs). However, in meat treated with W, W/L, and COMB, gas was produced after 4 to 5, 7 to 8, and 9 to 10 days of storage at 15 degrees C, respectively. These results demonstrate the effectiveness of multiple antimicrobial interventions in reducing H. alvei numbers on beef trim and subsequently delaying gas formation in the resulting ground beef chubs.

Animals↗
PubMedDate not supplied

Rapid decrease of the peripheral deiodination of thyroxine in malabsorption syndrome in artificially inoculated broilers.

Thyroid function of broilers inoculated with the intestinal homogenate from birds from a field case of malabsorption syndrome was investigated during the first 2 days postinoculation. In one experiment, different amounts of the inoculum were applied to see if there exists a dose-response relationship. As early as 3 hours after inoculation, there was a significant drop in the serum level of triiodothyronine and in the activity of the liver 5'-deiodinase (type I). Type II deiodinase activity was less impaired. A minimum of 0.3 ml of inoculum was effective, whereas 0.05 ml of the same homogenate elicited a significant (P less than 0.01) drop in liver deiodinase activity. These findings underline the importance of thyroid impairment in the pathogenesis of malabsorption syndrome.

Animals↗