Browsing by Subject "Campylobacter"
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Item Effects of short-chain nitrocompounds against Campylobacter jejuni and Campylobacter coli in vitro(Texas A&M University, 2007-04-25) Horrocks, Shane MichaelCampylobacter is an important human pathogen that colonizes the gut of food producing animals. In this study, the effects of 2-nitro-1-propanol, 2-nitroethanol, nitroethane, and 2-nitro-methyl-propionate (0, 10, and 20 mM) on growth of Campylobacter jejuni were tested during culture in Bolton Broth adjusted to pH 5.6, 7.0, or 8.2. The effects of the nitrocompounds were also tested against C. coli in Bolton Broth but adjusted to pH 8.2 only. Viable cell counts of samples taken at intervals during incubation revealed main effects (P < 0.05) of nitroethane, 2-nitro-1-propanol, 2- nitroethanol, and 2-nitro-methyl-propionate as evidence by reduced survivability of C. jejuni. A marked effect of pH on the survivability of C. jejuni during incubation with all compounds was observed, with greater activity observed at pH 8.2 than at pH 5.6 or 7.0 for nitroethane, 2-nitro-1-propanol, 2-nitroethanol, but not for 2-nitro-methyl-propionate. In the case of 2-nitro-methyl-propionate, survivability of C. jejuni was reduced most at pH 5.6. Except for 2-nitro-methyl-propionate, which was ineffective, all nitrocompounds elicited similar effects on C. coli when cultured at pH 8.2. The effect of nitroethane and 2-nitro-1-propanol (10 mM) on naturally-occurring Campylobacter was further investigated during incubation of a porcine fecal suspension. Campylobacter concentrations decreased more rapidly (P < 0.05) during incubation of porcine fecal suspensions supplemented with 2-nitro-1-propanol than unsupplemented control suspensions or suspensions supplemented with nitroethane thus reiterating the superior inhibitory effect of 2-nitro-1-propanol.Item Evaluation of pulse electric fields to reduce foodborne pathogen levels in scalder/chiller water during poultry processing(2009-05-15) Martin, Bradley CurtisPoultry slaughtering encompasses a series of processing steps with the objective of harvesting the consumable meat. The scalding process consists of the submersion of carcasses in hot water tanks to facilitate the removal of feathers during slaughter. However, the use of a common scalding tank increases the likelihood of carcass cross contamination considering that dirt, fecal material and even digestive and intestinal contents carrying pathogens and other bacteria are widely spread during this operation. Similar cross contamination occurs in the process of chilling carcasses, which also requires submersion of broilers in communal tanks filled with ice and cold water. A plausible approach to reduce contamination in scalders or chillers is the use of Pulsed Electric Fields (PEF) to decontaminate scalder/ chiller water. PEF uses electricity to kill bacteria suspended in liquid media and could be utilized in poultry scalders and chillers to reduce bacterial contamination on carcasses and reduce the potential risk of pathogens reaching the final consumer. A pilot scale system was assembled by the use of a pulse electric field generator (Model SF-700, Simmons. Eng. Co., Dallas, GA) coupled with a commercial scalding tank (Dunkmaster?, Knase Company Inc, MI). C. coli and C. jejuni along with marker strains of Novobiocin and Nalidixic acid resistant S. typhimurium and S. enteritidis strains were used in challenge studies evaluating the effects of the PEF on carcasses, scalder and chiller water contamination. The system was evaluated with 0, 0.5, and 1% sodium chloride in the water with 40 volts of electric current and 0.54 of amperage. Samples were collected at 0, 40, 80, 160, 200 s of treatment with a 10 s on, 5 s off cyclical pulses. The use of PEF in regular scalder/chiller water showed little effect on Salmonella and Campylobacter reductions. However, with the addition of 0.5% NaCl caused a significant (P<0.5) log CFU/ml reduction of Salmonella and Campylobacter within the scalder/chiller water at 40, 80, and 160 seconds respectively.Item Evaluation of Vaccines on the Prevalence of Salmonella and/or Campylobacter in Layer and Broiler Chickens(2013-05-22) Garcia, Javier ShalinThe control of foodborne pathogens especially Salmonella and Campylobacter are of great concern to the commercial poultry industry. The control of these pathogens could be essential in the reduction of foodborne illness and deaths related to eggs and poultry meat. Previous studies have found that the presence or disappearance of Salmonella or Campylobacter is linked to various environmental and management-based factors, of which include vaccines used in the industry. Presently, we evaluated the effect of the infectious bronchitis virus (IBV) vaccine on the incidence of Salmonella or Campylobacter prevalence in broiler chicks. In the current study, a high vaccine dosage of IBV vaccine was associated with an increase the prevalence of Campylobacter during the first two weeks of age. Although in a previous study a high vaccine dose of IBV was linked in to increased prevalence of Salmonella, this was not seen in our study. In a subsequent trial, we also evaluated the potential cross-protection against three Salmonella serotypes of two-previously formulated vaccines when used in various dosage combinations. The combination vaccine was effective in reducing shedding of S. Enteritidis however reduction of S. Typhimurium and S. Hadar were not seen consistently. The vaccines were also shown to not significantly affect the body weights of the birds. Vaccines have been an essential component in the control of diseases within flocks in the commercial poultry industry. Ensuring the uniform application of IBV vaccine could help prevent and/or reduce the prevalence of Campylobacter in broiler flocks. The combination vaccine was effective against one serotype of Salmonella but further trials are needed to complete evaluate its potential as a vaccine that could be used in the poultry industry.Item Herd-level Risk Factors Associated with Antimicrobial Susceptibility Patterns and Distributions in Fecal Bacteria of Porcine Origin.(2012-10-19) Rollo, Susan NobleThe purpose of this dissertation is threefold: to determine the differences in apparent prevalence and the antimicrobial susceptibility of Campylobacter spp. between antimicrobial-free and conventional swine farms; secondly, to introduce an appropriate statistical model to compare the minimum inhibitory concentration distributions of Escherichia coli and Campylobacter spp. isolated from both farm types; and thirdly, to examine the potential herd level risk factors that may be associated with antimicrobial resistance of Campylobacter spp. and E. coli isolates from finishers on antimicrobial-free and conventional farming systems. In addition, a critical review of studies that have compared the levels and patterns of antimicrobial resistance among animals from antimicrobial-free and conventional farming practices was performed. Fecal samples from 15 pigs were collected from each of 35 antimicrobial-free and 60 conventional farms in the Midwestern U.S. Campylobacter spp. was isolated from 464 of 1,422 fecal samples, and each isolate was tested for susceptibility to 6 antimicrobials. The apparent prevalence of Campylobacter spp. isolates was approximately 33 percent on both conventional and antimicrobial-free farms. The proportion of antimicrobial resistance among Campylobacter was higher for three antimicrobials within conventional compared to antimicrobial-free farms. The susceptibilities of populations of bacteria to antimicrobial drugs were summarized as minimum inhibitory concentration (MIC) frequency distributions. The use of MIC values removed the subjectivity associated with the choice of breakpoints which define an isolate as susceptible or resistant. A discrete-time survival analysis model was introduced as the recommended statistical model when MICs are the outcome. A questionnaire was completed by each farm manager on biosecurity, preventive medication, vaccines, disease history, and production management. Multivariable population-averaged statistical models were used to determine the relationships among antimicrobial susceptibility patterns and potential herd-level risk factors. Controlling for herd type (antimicrobial-free versus conventional), each antimicrobial-bacterial species combination yielded unique combinations of risk factors; however, housing type, history of rhinitis, farm ventilation, and history of swine flu were significant in more than one model. A variety of herd-level practices were associated with the prevalence of antimicrobial resistance on swine farms. Further studies are encouraged when considering interventions for antimicrobial resistance on both antimicrobial-free and conventional farms.Item Microbial intervention strategies for Salmonella and Campylobacter reduction in commercial turkey processing(Texas A&M University, 2005-08-29) Stevens, Scott MichaelOne objective of the present investigation was to compare Salmonella and Campylobacter recovery incidence from commercially processed turkeys immediately prior to and following pre-chill and immersion chiller intervention strategies being used in three distinct turkey processing facilities. In each plant, on a single day of processing, 100 carcass rinse samples prior to and following each post-evisceration, pre-chill intervention and following immersion chilling were obtained for Salmonella and Campylobacter recovery. Two of three plants demonstrated a trend of decreased Salmonella on carcasses following the Inside Outside Bird Wash (IOBW), with reductions of 13%, and 11% being observed for Plants 1 and 2, respectively. Results for reductions of Campylobacter contamination were not as straightforward, with only Plant 3 showing decreased levels (11% reduction) following the IOBW. Plant 2 used an additional pre-chill intervention, a low pressure, acetic acid final wash, which was not shown to be effective in causing an additional reduction in either Salmonella or Campylobacter on carcasses. In all three plants, properly managed immersion chilling systems were the most effective microbial intervention for achieving Salmonella andCampylobacter reduction on processed turkey carcasses. While not as effective, the IOBW present in each plant likely contributed to the effectiveness of immersion chiller interventions. If managed properly these intervention points have demonstrated themselves as a viable means to effectively reduce Salmonella and Campylobacter on processed turkeys. Another objective was to modify the scalder environment to an alkaline pH and determine the effects of thermal killing of Salmonella and Campylobacter. In each plant, on a single day of processing, 50 carcass rinse samples prior to and following scald tank immersion and following feather removal were obtained for Salmonella and Campylobacter recovery. Modification of the scald water to alkaline conditions (pH 9- 10) did not result in increased thermal killing of Salmonella or Campylobacter on turkey carcasses, as hypothesized before the investigation. Alkaline conditions are known to facilitate a more efficacious pluck and aid in the detachment of bacteria. Due to this, the bacteria that were recovered at these points on the processing line could have had an impact on the observed data.Item Molecular Typing and Antimicrobial Resistance of Campylobacter Isolated During Commercial Broiler Production(2012-02-14) Hernandez, Charles AndrewCampylobacter jejuni is a commensal microorganism of the poultry gastrointestinal tract. Broilers, layers, ducks, turkeys, and quails can be colonized by Campylobacter without illness occurring. The vast majority of human Campylobacter infections are recognized as being foodborne. For 2008, preliminary FoodNet data showed that the Campylobacter incidence of infection, 12.68 per 100,000 of the U.S. population, is the second highest, only behind Salmonella at 16.20 per 100,000. To further understand Campylobacter?s role as a foodborne pathogen, analysis at the molecular level is needed. Microbial molecular typing allows for identification and differentiation of bacterial strains beneath the species level. In this study, the ?gold standard? method for molecular subtyping, Pulsed Field Gel Electrophoresis (PFGE), along with Diversilab? repetitive element Polymerase Chain Reaction (rep-PCR) and 16S-23S Internal Spacer Region Denaturing Gradient Gel Electrophoresis (ISR DGGE) were used for the molecular typing of Campylobacter jejuni isolates obtained during different stages of commercial broiler production and processing. In addition, the C. jejuni isolates were tested for resistance to antimicrobials commonly used in both veterinary and human medicine. Antimicrobial resistance testing was carried out using a broth dilution system. The majority of recovered isolates came from post-harvest carcass rinsates. Carcass rinses were obtained at post-evisceration, post-chill stages. All isolates (n = 46) were identified by the Polymerase Chain Reaction as Campylobacter jejuni. Three genotypes (n = 44, n = 1, n = 1) were identified by PFGE. The 46 rep-PCR products grouped into seven clusters and two outliers. Clustering of rep-PCR products by sample source was not observed. No relatedness trends were observed for isolates recovered from the same source. The combination of PFGE and Diversilab rep-PCR methods provides highly discriminatory molecular typing results. These results provide practical epidemiological information that shows postevisceration and post-chill stages are still important targets for intervention studies. The very high occurrence of C. jejuni isolates exhibiting genotype A suggests it may differentially express certain gene(s) that enable this strain to more favorably survive under the different harsh environmental conditions encountered during production and processing. In addition, phenotypic testing revealed all of the isolates were not resistant to the antimicrobials azithromycin, ciprofloxacin, erythromycin, gentamycin, tetracycline, florfenicol, nalidixic acid, telithromycin, and clindamycin at any of the concentrations tested. All the C. jejuni isolates exhibited an indistinguishable two-band 16S-23S ISR DGGE profile. Overall, these C. jejuni commercial broiler pre- and post-harvest isolates exhibited an extremely low degree of molecular and phenotypic variability.Item Non-O157 Shiga Toxin-producing Escherichia Coli(STEC), campylobacter and, salmonella prevalence in ground beef and whole muscle beef cuts at retail in the United States(2011-05) Vipham, Jessie L.; Miller, Markus F.; Brashears, Mindy M.; Loneragan, Guy H.; Brooks, Chance J.Salmonella, Campylobacter, Non-O157 STEC cause considerable human illnesses each year, and the vast majority of cases are food borne. Currently, very little is known about the burden of these pathogens in the U.S. beef supply. The purpose of this study was to establish the prevalence of Campylobacter, Salmonella, and Non-O157 STEC in beef products collected from U.S. retail markets. Sample collection occurred during the months of February through May, 2010. Thirty two American cities comprising 28 states were sampled in this study. Retail raw ground and whole muscle beef (n = 2,915) samples were purchased and examined for the presence of Salmonella. Samples were enriched in tryptic soy broth (TSB) and incubated for 24 h at 37°C. Salmonella positives were confirmed using the AOAC approved BAX® system rtPCR. Of the original samples purchased, 1,211 were randomly selected and tested for Campylobacter. Positive samples were confirmed through direct plating and latex agglutination. Samples were enriched using Bolton Broth incubated for 48 h at 42°C and grown on blood-free Campylobacter plates in required microaerophilic conditions. A sub-sample (n = 325) were enriched in TSB and glycerol (TSB+glyc) and frozen at -80°C to be analyzed at a later date. Samples were screened for putative non-O157 STEC using rtPCR methods. Salmonella was detected in 0.65% of the total samples purchased. The prevalence for whole muscle cuts was 1.02%, and Salmonella was present in 0.54% of ground beef samples. Campylobacter was recovered from 9.3% of samples (n = 112), with a prevalence of 17.24% in whole muscle cuts and 7.35% in ground beef. Putative non-O157 STEC antigens were detected in 5.9% of samples. Whole muscle cuts had a prevalence of 4.11%, and ground beef sample prevalence was 6.99%. The most common serotypes detected in this study were O26 (3.8%), O145 (2.2%), O103 (1.3%), and O111 (0.98%). A chi-square analysis was conducted using the FREQ procedure of SAS. A greater percentage of O26 was observed compared to O111 and O103 (P = 0.01 and P = 0.04, respectively); however, no other comparisons between putative non-O157 STEC were significant (P > 0.05). Whole muscle cuts had a higher prevalence of Campylobacter compared to ground beef (P < 0.01),; however, comparisons between whole muscle cuts and ground beef for the other two pathogens were not significant (P > 0.05). Creating pathogen baselines in U.S. retail beef is imperative for targeting interventions for pathogen control. These data can be utilized for a more complete understanding of these pathogens and their impact on public health from the consumption of beef products.Item The Effect of Thymol-B-D-Glucopyranoside on the Reduction of Campylobacter Species in Food-Producing Animals(2013-06-06) Epps, Sharon V.R.Campylobacter are a leading cause of bacterial derived foodborne illness. Thymol is a natural product that reduces survivability of Campylobacter in vitro. Results from animal studies, however, indicate that absorption or degradation within the stomach and small intestine may preclude delivery of thymol to the cecum and large intestine, the main sites of Campylobacter colonization. Presently, we compared the anti- Campylobacter activity of thymol against that of thymol-?-D-glucopyranoside (?-Dthymol), the latter suspected to be resistant to degradation and absorption in the proximal alimentary tract lacking ?-glycosidase activity. When treated with 1 mM thymol, the survivability of Campylobacter coli and jejuni in vitro was reduced by 3.41 to 6.87 log_10 CFU mL-1 after 48-h pure culture and after co-culture, respectively. In the presence of a ?-glycosidase-expressing Parabacteroides distasonis. Conversely, the survivability of C. coli and C. jejuni was reduced by 3.72 and 4.30 log_10 CFU mL-1, respectively, in cocultures treated with ?-D-thymol, but not in pure cultures similarly treated. When tested in mixed cultures of porcine or bovine fecal microbes possessing endogenous ?- glycosidase, C. coli and C. jejuni survivability was reduced by 3.26 and 2.50 log_10 CFU mL-1, respectively, whether treated with thymol or ?-D-thymol. In mixed populations of avian crop and cecal microbes, C. jejuni survivability was reduced 1.41 to 2.32 log_10 CFU mL-1 whether treated with thymol or ?-D-thymol. Thymol and ?-D-thymol inhibited ammonia accumulation in mixed populations of porcine and mixed bovine fecal microbes which is consistent with free thymol?s purported role as a deaminase inhibitor. Conversely, thymol and ?-D-thymol did not affect ammonia accumulation in mixed populations of avian gut microbes implicating population specific effects of these compounds. ?-D-thymol, but not thymol, reduced accumulation of fermentation acids indicating the conjugate inhibited fermentation which may limit its application to the last meal or last few meals before harvest. Oral administration of 150 ?mol ?-D-thymol reduced C. jejuni in avian crop, but not in cecal contents; treatment with thymol was ineffective. These results indicate that ?-D-thymol, or similar ?-glycosides, may be a suitable candidate to escape absorption and degradation within the proximal alimentary and retain its anti-Campylobacter properties. Further research is needed to reduce such technology to practice.