Careful with that cow: 56 sick from Salmonella linked to contact with dairy

The U.S. Centers for Disease Control reports this outbreak investigation is over. Illnesses could continue because people may not know they could get a Salmonella infection from contact with dairy calves or other cattle.

CDC, several states, and the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (USDA-APHIS) investigated a multistate outbreak of multidrug-resistant Salmonella Heidelberg infections. Epidemiologic and laboratory evidence indicated that contact with dairy calves and other cattle was the likely source of this outbreak.

A total of 56 people infected with the outbreak strains of Salmonella Heidelberg were reported from 15 states.  Illnesses started on dates ranging from January 27, 2015 to November 25, 2017. Of those with available information:

35% of people were hospitalized. No deaths were reported.

35% of people in this outbreak are children younger than 5 years.

Epidemiologic, laboratory, and traceback investigations linked ill people in this outbreak to contact with calves, including dairy calves.

In interviews, ill people answered questions about contact with animals and foods eaten in the week before becoming ill. Of the 54 people interviewed, 34 (63%) reported contact with dairy calves or other cattle. Some of the ill people interviewed reported that they became sick after their calves became sick or died.

Surveillance in veterinary diagnostic laboratories showed that calves in several states were infected with the outbreak strains of multidrug-resistant Salmonella Heidelberg

Information collected earlier in the outbreak indicated that most of the calves came from Wisconsin. Regulatory officials in several states attempted to trace the origin of calves linked to more recent illnesses. A specific source of cattle linked to newer illnesses was not identified.

Antibiotic resistance testing conducted by CDC on clinical isolates from ill people shows that the isolates were resistant to multiple antibiotics.

Antibiotic resistance may be associated with increased risk of hospitalization, development of a bloodstream infection, or treatment failure in patients.

Whole genome sequencing analysis identified predicted antibiotic resistance in outbreak-associated isolates from 48 ill people, in 88 isolates from cattle, and in 13 isolates from animal environments.

These findings match results from standard antibiotic resistance testing methods used by CDC’s National Antimicrobial Resistance Monitoring System (NARMS) laboratory on 10 isolates from 9 ill people and 1 animal. All 10 isolates were resistant to amoxicillin-clavulanic acid, ampicillin, cefoxitin, ceftriaxone, streptomycin, sulfisoxazole, and tetracycline. In addition, nine had reduced susceptibility to ciprofloxacin, nine were  resistant to trimethoprim-sulfamethoxazole, six were resistant to nalidixic acid, four were resistant to chloramphenicol, and one was resistant to gentamicin. All 10 isolates tested were susceptible to azithromycin and meropenem.

Follow these steps to prevent illness when working with any livestock:

Always wash your hands thoroughly with soap and water right after touching livestock, equipment, or anything in the area where animals live and roam. Use dedicated clothes, shoes, and work gloves when working with livestock. Keep and store these items outside of your home.

It is especially important to follow these steps if there are children younger than 5 years in your household. Young children are more likely to get a Salmonella infection because their immune systems are still developing.

Work with your veterinarian to keep your animals healthy and prevent diseases.

It is important to remember that cattle can carry Salmonella and not appear sick. However, in this outbreak, some people did notice illness in their cattle, especially among calves. Livestock handlers should watch for sicknesses in dairy calves and consult their veterinarian if needed.

Woman’s rare eye infection highlights (low) risk of parasite spread by flies

Susan Perry of the Minnesota Post reports an Oregon woman is the first known person to become infected with a tiny parasitic worm that lives in the eyes of cattle, according to a case study report published Monday by researchers at the Centers for Disease Control and Prevention (CDC).

Although common in animals, eye-worm infections in humans are extremely rare. And, if caught and treated early, they don’t cause any permanent damage to the eye.

“This is only the 11th time a person has been infected by eye worms in North America,” lead author Richard Bradbury, who heads the CDC’s Parasite Diagnostics and Biology Laboratory, told CNN. “But what was really exciting it that it is a new species that has never infected people before. It’s a cattle worm that somehow jumped into a human.”

The woman, 28-year-old Abby Beckley, was working on a salmon boat in Alaska two summers ago when her left eye became irritated and inflamed. A week later, when the symptoms didn’t go away, she decided to investigate.

BuzzFeed reporter Nidhi Subbaraman, who interviewed Beckley, describes what happened next:

Standing at the mirror in the galley, [Beckley] plucked at her eyeball, as if extracting a contact lens. 

“I put my fingers in there in kind of a picking motion and I pulled out a worm,” Beckley [said]. “I looked at my finger and it was moving and I was shocked.” 

Beckley said she woke up her bunkmate to show her the worm, a piece of tangled white fluff wriggling at the end of her index finger. “She confirmed I wasn’t crazy,” Beckley said.

Over the course of the next few days she pulled out about a half dozen more worms. “I was living with these things, and I’d just keep pulling them out when I’d feel them,” Beckley said. 

Beckley flew home and went to see specialists at the Oregon Science and Health Laboratory in Portland. They extracted two more worms, and sent one to the CDC for analysis. It was identified as being the nematode Thelazia gulosa, which commonly infects the eyes of cattle, but had never been found in humans.

The case report was published online in the American Journal of Tropical Medicine and Hygiene, where it can be read in full.

Salmonella Dublin is nasty

Salmonella enterica serotype Dublin is a cattle-adapted bacterium that typically causes bloodstream infections in humans.

To summarize demographic, clinical, and antimicrobial drug resistance characteristics of human infections with this organism in the United States, we analyzed data for 1968–2013 from 5 US surveillance systems.

During this period, the incidence rate for infection with Salmonella Dublin increased more than that for infection with other Salmonella. Data from 1 system (FoodNet) showed that a higher percentage of persons with Salmonella Dublin infection were hospitalized and died during 2005–2013 (78% hospitalized, 4.2% died) than during 1996-2004 (68% hospitalized, 2.7% died). Susceptibility data showed that a higher percentage of isolates were resistant to >7 classes of antimicrobial drugs during 2005–2013 (50.8%) than during 1996–2004 (2.4%).

Epidemiology of Salmonella enterica Serotype Dublin infections among humans, United State, 1968-2013

Emerging Infectious Diseases, vol. 23, no. 9, September 2017, R. Reid Harvey, Cindy R. Friedman, Stacy M. Crim, Michael Judd, Kelly A. Barrett, Beth Tolar, Jason P. Folster, Patricia M. Griffin, and Allison C. Brown

https://wwwnc.cdc.gov/eid/article/23/9/17-0136_article

Dehydration and salt toxicity? Cows dying in Saskatchewan

Ann Hui of The Globe and Mail reports that for decades, cattle farmers have sent their livestock to graze on the sprawling Shamrock pasture, about 80 kilometres south of Chaplin in southwest Saskatchewan. Shamrock is where Russ Coward, a fourth-generation cattle farmer, has for years raised nearly a quarter of his cattle. It’s the same place Mr. Coward’s father sent his cattle.

But some time between last Monday and Friday, the cows and calves at Shamrock began to die. It’s not known whether the deaths happened all at once or slowly over the course of the four days. But by the time the manager arrived on Friday afternoon, 200 of the approximately 680 cattle in a single field were dead.

The president of Shamrock Grazing Ltd., Glenn Straub, called Mr. Coward, who raced out to the field. He was met with a gruesome scene. “We seen a tragedy,” he said. “We simply seen a terrible sight.”

Other ranchers soon joined him, about 31 in total who have cows and calves there. “We all had the same feelings – how did this happen? How did this happen?”

Since Friday, provincial authorities as well as the local RCMP have been trying to piece together the mystery. The cause is still being determined, but the prevailing theory is dehydration and salt toxicity.

The area has been subject to drought in recent weeks, said Saskatchewan’s chief veterinary officer, Betty Althouse. Officials believe this may have led to evaporation at the water source, resulting in higher concentrations of salt in the water.

“An analogy would be someone shipwrecked in the ocean,” Dr. Althouse told reporters this week. “They’re thirsty, they’re craving water, so they’re going to drink the water. But ultimately the salt water will kill them.”

Many of the dead cows and calves were found clustered around one “dugout” in particular – the pools of collected rain and runoff where they drink. Investigators at the Western College of Veterinary Medicine in Saskatoon who were called in to assist have collected samples from the dugouts. Results are expected some time this week.

Reinfection of cattle with E. coli

Enterohaemorrhagic Escherichia coli (EHEC), like E. coli O157:H7 are frequently detected in bovine faecal samples at slaughter. Cattle do not show clinical symptoms upon infection, but for humans the consequences after consuming contaminated beef can be severe.

epa01322503 View of some of the more than 7,000 cattle that arrived to Liniers Market in Buenos Aires, Argentina, on 22 April 2008, to be slaughtered. Argentinean government and the biggest agriculture organizations had been discussing, this morning, the situation of milk sector that is one of the most conflictive topics on the negotiations with cow meat, grains and regional economies. EPA/CEZARO DE LUCA

The immune response against EHEC in cattle cannot always clear the infection as persistent colonization and shedding in infected animals over a period of months often occurs. In previous infection trials, we observed a primary immune response after infection which was unable to protect cattle from re-infection. These results may reflect a suppression of certain immune pathways, making cattle more prone to persistent colonization after re-infection.

To test this, RNA-Seq was used for transcriptome analysis of recto-anal junction tissue and ileal Peyer’s patches in nine Holstein-Friesian calves in response to a primary and secondary Escherichia coli O157:H7 infection with the Shiga toxin (Stx) negative NCTC12900 strain. Non-infected calves served as controls.

In tissue of the recto-anal junction, only 15 genes were found to be significantly affected by a first infection compared to 1159 genes in the ileal Peyer’s patches. Whereas, re-infection significantly changed the expression of 10 and 17 genes in the recto-anal junction tissue and the Peyer’s patches, respectively. A significant downregulation of 69 immunostimulatory genes and a significant upregulation of seven immune suppressing genes was observed.

Although the recto-anal junction is a major site of colonization, this area does not seem to be modulated upon infection to the same extent as ileal Peyer’s patches as the changes in gene expression were remarkably higher in the ileal Peyer’s patches than in the recto-anal junction during a primary but not a secondary infection. We can conclude that the main effect on the transcriptome was immunosuppression by E. coli O157:H7 (Stx) due to an upregulation of immune suppressive effects (7/12 genes) or a downregulation of immunostimulatory effects (69/94 genes) in the ileal Peyer’s patches. These data might indicate that a primary infection promotes a re-infection with EHEC by suppressing the immune function.

Potential immunosuppressive effects of Escherichia coli O157:H7 experimental infection on the bovine host

BMC Genomics; 2016; 17:1049; DOI: 10.1186/s12864-016-3374-y; Published: 21 December 2016

E. Kieckens, J. Rybarczyk, R. W. Li, D. Vanrompay, and E. Cox

http://bmcgenomics.biomedcentral.com/articles/10.1186/s12864-016-3374-y

Lower the loads: Phages don’t seem to work to lower E. coli O157 in cattle

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Escherichia coli O157:H7 is a major food safety concern for the beef industry. Several studies have provided evidence that cattle hides are the main source of beef carcass contamination during processing and that reductions in the E. coli O157:H7 load on the hides of cattle entering processing facilities will lead to reductions in carcass contamination. Bacteriophages have been proposed as a novel preharvest antimicrobial intervention to reduce the levels of E. coli O157:H7 on cattle hides.

lairageThe objective of this study was to evaluate a commercialized phage application administered in the lairage area of commercial beef processing plants for the ability to reduce E. coli O157:H7 contamination of cattle hides and carcasses. Cattle lots either received phage spray treatment (n = 289) or did not (n = 301), as they entered the lairage environments in two separate experiments at two different commercial beef processing plants. Hide and carcass samples were collected and analyzed for E. coli O157:H7 prevalence and concentration. Cattle hides receiving phage treatment had an E. coli O157:H7 prevalence of 51.8%, whereas untreated hides had a prevalence of 57.6%. For carcass samples, the E. coli O157 prevalence in treated and untreated samples was 17.1% and 17.6%, respectively.

The results obtained from these experiments demonstrated that the treatment of cattle hides with bacteriophages before processing did not produce a significant reduction of E. coli O157:H7 on cattle hides or beef carcasses during processing.

Evaluation of bacteriophage application to cattle in lairage at beef processing plants to reduce Escherichia coli O157:H7 prevalence on hides and carcasses

Arthur Terrance M., Kalchayanand Norasak, Agga Getahun E., Wheeler Tommy L., and Koohmaraie Mohammad

http://online.liebertpub.com/doi/abs/10.1089/fpd.2016.2189

Toddler contracts serious E. coli infection on NZ family farm

Eight months on from a rescue helicopter dash to Starship children’s hospital, two-year-old Grace Dheda is enjoying being back on her family’s farm – even though it nearly killed her.

grace-dhedaIn March, Grace and her family were savouring rural life in Wellsford.

Mum Megan and Dad Kirin were planning their up-coming wedding. 

That all came to a sudden halt when their daughter began to show signs of illness.

After two days of vomiting and diarrhea, a doctor diagnosed a tummy bug.

Grace was sent home and prescribed plenty of fluids, Megan says.

At home Grace played on the deck like her normal self, but collapsed at bedtime.

Grace was rushed back to the doctors.

“They put her on oxygen straight away. She’d been unconscious for about 45 minutes and they were starting to worry about potential brain damage.”

Given the severity of the situation and the closest ambulance an hour away, the Auckland Westpac Rescue Helicopter was called.

Grace and Megan were ferried to a helipad and arrived to see the chopper landing.

“It was such a relief to see the helicopter,” Megan says.

Megan recalls, “At first nobody knew what was wrong with her and why she was having these seizures. It wasn’t until a few days before we left the hospital that we found out she had contracted E. coli and HUS (Hemolytic Uremic Syndrome).”

HUS is a severe complication of the E. coli infection that can lead to kidney failure.

At first it was thought that Grace had contracted the bacterial infection through the water supply, however this was later tested and found to be normal.

It is now believed that she contracted it via the farm animals.

Megan says, “We’ve got cows here on the farm and I don’t like Grace going anywhere near them. The doctor told me I have ‘parental anxiety.’ ‘I love the farm life, but I’m a bit paranoid now and have about 20 bottles of sanitiser around the place.”

The Helicopter Trust is actively fundraising at present in order to purchase three new ventilators for use on their helicopters and in their Rapid Response Vehicle.

A lot of STEC: Numbers mean new interventions

Shiga toxin-producing Escherichia coli (STEC) strains can colonize cattle for several months and may, thus, serve as gene reservoirs for the genesis of highly virulent zoonotic enterohemorrhagic E. coli (EHEC).

Cattle-Heat-Load-ForecastingAttempts to reduce the human risk for acquiring EHEC infections should include strategies to control such STEC strains persisting in cattle. We therefore aimed to identify genetic patterns associated with the STEC colonization type in the bovine host. We included 88 persistent colonizing STEC (STECper) (shedding for ≥4 months) and 74 sporadically colonizing STEC (STECspo) (shedding for ≤2 months) isolates from cattle and 16 bovine STEC isolates with unknown colonization types. Genoserotypes and multilocus sequence types (MLSTs) were determined, and the isolates were probed with a DNA microarray for virulence-associated genes (VAGs). All STECper isolates belonged to only four genoserotypes (O26:H11, O156:H25, O165:H25, O182:H25), which formed three genetic clusters (ST21/396/1705, ST300/688, ST119). In contrast, STECspo isolates were scattered among 28 genoserotypes and 30 MLSTs, with O157:H7 (ST11) and O6:H49 (ST1079) being the most prevalent. The microarray analysis identified 139 unique gene patterns that clustered with the genoserotypes and MLSTs of the strains. While the STECper isolates possessed heterogeneous phylogenetic backgrounds, the accessory genome clustered these isolates together, separating them from the STECspo isolates.

Given the vast genetic heterogeneity of bovine STEC strains, defining the genetic patterns distinguishing STECper from STECspo isolates will facilitate the targeted design of new intervention strategies to counteract these zoonotic pathogens at the farm level.

The accessory genome of Shiga toxin-producing Escherichia coli defines a persistent colonization type in cattle

Appl Environ Microbiol 82:5455–5464. doi:10.1128/AEM.00909-16.

SA Barth, C Menge, I Eichhorn, T Semmier, LH Wieler, D Pickard, A Belka, C Berens, L Geue

http://aem.asm.org/content/82/17/5455.abstract?etoc

Not a Letterman list: Top 6 STECs in Canada

The incidence of the top 6 STEC serotypes was determined in two beef slaughter houses. In total, 328 samples were taken of hides, de-hided carcasses and the plant environment. Samples were enriched in Tryptic Soy Broth containing novobiocin then screened using RT-PCR GeneDiskÒ system that targeted stx, eae and wzx genes.

top.10.lettermanIt was found that 92.5% (172 of 186) of the hide samples. 72.5% (29 of 40) de-hided samples and 84.3% (86 of 102) of the environmental samples returned presumptive positive results. Serotypes O103, O45 and O121 were most commonly encountered although all the Top 6 serotypes were represented within individual samples. However, attempts to recover the Top 6 serotypes by culturing proved unsuccessful despite screening up to 20 colonies per CHROMAgar® plate of enriched sample. The reasons for the discrepancy between the RT-PCR and culture methods were found to be due to low levels of the target in enriched samples, presence of virulence factors in different cells and also the transient retention of stx. With regards the latter it was found that strains harboring a full set of virulence factors (eae, stx) were more common in grown cultures held post-incubation at 4 °C for 14 days. Moreover, no stx gene was recovered when isolates were sub-cultured on TSA but was present in the same strains grown on CHROMAgar®. In total 39 STEC isolates were recovered with the majority harboring stx1, stx2, eae and hylA. Only 3 of the isolates had stable complement of virulence factors and were identified as O172:H28, O76:H7 and O187:H52.

Although no Top 6 STEC were isolated the presence of virulent strains on carcasses with the potential to cause Hemolytic Uremic Syndrome is of concern. The significance of those STEC that transiently harbor virulence factors is unclear although clearly impacts on diagnostic performance robustness when screening for the Top 6 non-O157 STEC.

Incidence of Top 6 shiga toxigenic Escherichia coli within two Ontario beef processing facilities: Challenges in screening and confirmation testing

AIMS Microbiology, 2016, 2(3): 278-291. DOI: 10.3934/microbial.2016.3.278

Bannon, M. Melebari, C. Jordao Jr., C.G. Leon-Velarde, K. Warriner

http://www.aimspress.com/article/10.3934/microbiol.2016.3.278

Cattle be shedding STECs

Shiga toxin-producing Escherichia coli (STEC) is an important foodborne pathogen that can cause hemorrhagic colitis and hemolytic-uremic syndrome. Cattle are the primary reservoir for STEC, and food or water contaminated with cattle feces is the most common source of infections in humans.

beef.cattleConsequently, we conducted a cross-sectional study of 1,096 cattle in six dairy herds (n = 718 animals) and five beef herds (n = 378 animals) in the summers of 2011 and 2012 to identify epidemiological factors associated with shedding.

Fecal samples were obtained from each animal and cultured for STEC. Multivariate analyses were performed to identify risk factors associated with STEC positivity. The prevalence of STEC was higher in beef cattle (21%) than dairy cattle (13%) (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.25, 2.47), with considerable variation occurring across herds (range, 6% to 54%). Dairy cattle were significantly more likely to shed STEC when the average temperature was >28.9°C 1 to 5 days prior to sampling (OR, 2.5; 95% CI, 1.25, 4.91), during their first lactation (OR, 1.8; 95% CI, 1.1, 2.8), and when they were <30 days in milk (OR, 3.9; 95% CI, 2.1, 7.2). These data suggest that the stress or the negative energy balance associated with lactation may result in increased STEC shedding frequencies in Michigan during the warm summer months.

Future prevention strategies aimed at reducing stress during lactation or isolating high-risk animals could be implemented to reduce herd-level shedding levels and avoid transmission of STEC to susceptible animals and people.

STEC shedding frequencies vary considerably across cattle herds in Michigan, and the shedding frequency of strains belonging to non-O157 serotypes far exceeds the shedding frequency of O157 strains, which is congruent with human infections in the state. Dairy cattle sampled at higher temperatures, in their first lactation, and early in the milk production stage were significantly more likely to shed STEC, which could be due to stress or a negative energy balance. Future studies should focus on the isolation of high-risk animals to decrease herd shedding levels and the potential for contamination of the food supply.

Factors associated with Shiga toxin-producing Escherichia coli shedding by dairy and beef cattle

Cristina Venegas-Vargasa*, Scott Hendersona,b, Akanksha Khareb*,Rebekah E. Moscib, Jonathan D. Lehnertb*, Pallavi Singhb,Lindsey M. Ouelletteb*, Bo Norbya, Julie A. Funka, Steven Rustc, Paul C. Bartletta,Daniel Groomsa and Shannon D. Manningb

aDepartment of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan, USA

bDepartment of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA

cDepartment of Animal Science, Michigan State University, East Lansing, Michigan, USA

Applied and Environmental Microbiology, August 2016, Volume 82, Number 16, Pages 5049-5056, doi:10.1128/AEM.00829-16

http://aem.asm.org/content/82/16/5049.abstract?etoc