Prevalence and Molecular Characterization of Escherichia coli O157:H7 by Multiple-Locus Variable-Number Tandem Repeat Analysis and Pulsed-Field Gel Electrophoresis in Three Sheep Farming Operations in California

Kilonzo, Christopher; Atwill, Edward R.; Mandrell, Robert E.; Garrick, Melissa; Villanueva, Verónica Díaz; Hoar, Bruce R.

doi:10.4315/0362-028x.jfp-10-529

Cited by 17 publications

(19 citation statements)

References 53 publications

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“…Seasonal variation in shedding of food-borne pathogens by domestic animals has been widely reported (44)(45)(46). However, few studies have investigated this phenomenon in wild animals.…”

Section: Discussionmentioning

confidence: 99%

Fecal Shedding of Zoonotic Food-Borne Pathogens by Wild Rodents in a Major Agricultural Region of the Central California Coast

Kilonzo

Vivas

et al. 2013

Appl Environ Microbiol

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bRecent outbreaks of food-borne illness associated with the consumption of produce have increased concern over wildlife reservoirs of food-borne pathogens. Wild rodents are ubiquitous, and those living close to agricultural farms may pose a food safety risk should they shed zoonotic microorganisms in their feces near or on agricultural commodities. Fecal samples from wild rodents trapped on 13 agricultural farms (9 produce, 3 cow-calf operations, and 1 beef cattle feedlot) in Monterey and San Benito Counties, CA, were screened to determine the prevalence and risk factors for shedding of several food-borne pathogens. Deer mice (Peromyscus maniculatus) were the most abundant rodent species trapped (72.5%). Cryptosporidium species (26.0%) and Giardia species (24.2%) were the predominant isolates from rodent feces, followed by Salmonella enterica serovars (2.9%) and Escherichia coli O157:H7 (0.2%). Rodent trap success was significantly associated with detection of Salmonella in rodent feces, while farm type was associated with fecal shedding of Cryptosporidium and Giardia. Seasonal shedding patterns were evident, with rodents trapped during the spring and summer months being significantly less likely to be shedding Cryptosporidium oocysts than those trapped during autumn. Higher rodent species diversity tended to correlate with lower fecal microbial prevalence, and most spatiotemporal pathogen clusters involved deer mice. Rodents in the study area posed a minimal risk as environmental reservoirs of E. coli O157:H7, but they may play a role in environmental dissemination of Salmonella and protozoa. Rodent control efforts that potentially reduce biodiversity may increase pathogen shedding, possibly through promotion of intraspecific microbial transmission.

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“…Seasonal variation in shedding of food-borne pathogens by domestic animals has been widely reported (44)(45)(46). However, few studies have investigated this phenomenon in wild animals.…”

Section: Discussionmentioning

confidence: 99%

Fecal Shedding of Zoonotic Food-Borne Pathogens by Wild Rodents in a Major Agricultural Region of the Central California Coast

Kilonzo

Vivas

et al. 2013

Appl Environ Microbiol

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“…In a year-long study of the prevalence of E. coli O157 in sheep raised in a feedlot setting or on native pasture. Kilonzo et al (23) reported that 22.7% of fecal samples collected from feedlot sheep and 1.9% in sheep raised on pasture were positive for E. coli O157:H7.…”

Section: 05)mentioning

confidence: 99%

Prevalence of Escherichia coli O157:H7 and Salmonella in Camels, Cattle, Goats, and Sheep Harvested for Meat in Riyadh

Bosilevac

Gassem

Sheddy

et al. 2015

Journal of Food Protection

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Escherichia coli O157:H7 and Salmonella are significant foodborne pathogens that can be found in the feces and on the hides of meat animals. When hides are removed during the harvest process, the carcass and subsequent meat products can become contaminated. Camels, cattle, sheep, and goats are harvested for meat in Riyadh, Saudi Arabia. The prevalence of E. coli O157:H7 and Salmonella are unknown in these animals, and it is assumed that if the animals carry the pathogens in their feces or on their hides, meat products are likely to become contaminated. To this end, a minimum of 206 samples each from hides and feces of camels, cattle, goats, and sheep were collected over the course of 8 months and tested for E. coli O157:H7 and Salmonella. It was found that E. coli O157:H7 was present in feces (10.7, 1.4, 2.4, and 2.4%) and on hides (17.9, 8.2, 2.9, and 9.2%) of cattle, goats, camels, and sheep, respectively. The prevalence of Salmonella was 11.2, 13.5, 23.2, and 18.8% in feces and 80.2, 51.2 67.6, and 60.2% on hides of cattle, goats, camels, and sheep, respectively. The prevalence of E coli O157:H7 was nearly zero in all samples collected in June and July, while Salmonella did not exhibit any seasonal variation. These results constitute the first comprehensive study of E. coli O157:H7 and Salmonella prevalence in Saudi Arabian meat animals at harvest.

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“…Escherichia coli O157 samples were enriched in tryptic soy broth (TSB), exposed to an immunomagnetic separation step and then cultured on cefixime potassium tellurite sorbitol MacConkey (CT SMAC) and Rainbow agar containing novobiocin and tellurite (NT Rainbow) as previously described Kilonzo et al 2011). E. coli O157:H7 colonies identified were further analyzed by real-time PCR (RT-PCR) to detect presence of virulence genes.…”

Section: Jorge Celismentioning

confidence: 99%

“…Standard microbiological techniques were used to enumerate commensal E. coli (those generally regarded as nonpathogenic) (APHA 2012) and to identify two potential pathogens, E. coli O157:H7 (Kilonzo et al 2011) and Salmonella species (US EPA 2011). We determined mean coliform bacteria concentration in feces and soil by dispersing 0.035 ounce (1.0 gram) of feces or soil in 1.32 fluid ounces (39 milliliters) of phosphate buffered solution (PBS) using a rotational mixer for 5 minutes.…”

Section: Measuring Fecal Bacteriamentioning

confidence: 99%

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Buffers between grazing sheep and leafy crops augment food safety

Hoar¹,

Atwill²,

Carlton³

et al. 2013

Cal Ag

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The presence of livestock in or near fresh-market vegetable fields has raised concerns about the potential for contaminating produce with pathogenic bacteria. To develop buffer zones for grazing near production of leafy greens, we assessed the prevalence of Escherichia coli O157:H7 and Salmonella species in sheep that were grazed on alfalfa fields during the winter in California's Imperial Valley. We found E. coli O157:H7 in 1.8% of fecal samples and 0.4% of soil samples, and Salmonella in 0.8% of fecal samples and 0.4% of soil samples. Our results indicate that sheep grazing on alfalfa in the Imperial Valley have a low prevalence of these pathogens in their feces and that these bacteria are rarely found in soil from fields with grazing sheep. The California Leafy Green Products Handler Marketing Agreement guideline of 30 feet between grazing lands or domestic animals and the crop edge is adequate to minimize potential contamination of nearby crops.

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Prevalence and Molecular Characterization of Escherichia coli O157:H7 by Multiple-Locus Variable-Number Tandem Repeat Analysis and Pulsed-Field Gel Electrophoresis in Three Sheep Farming Operations in California

Cited by 17 publications

References 53 publications

Fecal Shedding of Zoonotic Food-Borne Pathogens by Wild Rodents in a Major Agricultural Region of the Central California Coast

Fecal Shedding of Zoonotic Food-Borne Pathogens by Wild Rodents in a Major Agricultural Region of the Central California Coast

Prevalence of Escherichia coli O157:H7 and Salmonella in Camels, Cattle, Goats, and Sheep Harvested for Meat in Riyadh

Buffers between grazing sheep and leafy crops augment food safety

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