Contamination level and ingestion dose of foodborne pathogens associated with infections

Hara-Kudo, Yukiko; Takatori, Kosuke

doi:10.1017/s095026881000292x

Cited by 115 publications

(68 citation statements)

References 11 publications

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“…Strains were allowed to colonize for 7 days when cecal contents were isolated, and bacterial counts were determined for each strain using the Campylobacter selective media mentioned above. Additionally, the wild-type and the mapA mutant strains were individually introduced into day-of-hatch chicks using the same inocula of approximately 5 ϫ 10 4 . Similarly, at 7 days postinoculation, cecal contents were harvested and C. jejuni numbers were determined.…”

Section: Analysis Of Inseq Resultsmentioning

confidence: 99%

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High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Johnson

Livny

DiRita

2014

Journal of Bacteriology

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bCampylobacter jejuni is a leading cause of gastrointestinal infections worldwide, due primarily to its ability to asymptomatically colonize the gastrointestinal tracts of agriculturally relevant animals, including chickens. Infection often occurs following consumption of meat that was contaminated by C. jejuni during harvest. Because of this, much interest lies in understanding the mechanisms that allow C. jejuni to colonize the chicken gastrointestinal tract. To address this, we generated a C. jejuni transposon mutant library that is amenable to insertion sequencing and introduced this mutant pool into day-of-hatch chicks. Following deep sequencing of C. jejuni mutants in the cecal outputs, several novel factors required for efficient colonization of the chicken gastrointestinal tract were identified, including the predicted outer membrane protein MapA. A mutant strain lacking mapA was constructed and found to be significantly reduced for chicken colonization in both competitive infections and monoinfections. Further, we found that mapA is required for in vitro competition with wild-type C. jejuni but is dispensable for growth in monoculture.

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Section: Analysis Of Inseq Resultsmentioning

confidence: 99%

“…During processing of meat products, bacteria are released from the gastrointestinal tracts of these animals, contaminating the meat. Following consumption of either undercooked poultry or contaminated food, human infection often occurs from inocula as low as 360 organisms and results in moderate to severe and bloody diarrhea (4).…”

mentioning

confidence: 99%

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Johnson

Livny

DiRita

2014

Journal of Bacteriology

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“…Improved stress tolerance in enteric pathogens would enhance their environmental survival and correspond possibly to increased infections. One striking feature shared by the enteric pathogens E. coli O157:H7 and Shigella is their high acid resistance, which was proposed to contribute to, at least in part, their low infective dose (19,20). Prior to ingestion by an animal host, enteric pathogens often have been living in an environment where biochemical and physiological conditions were not optimal for their growth.…”

Section: Discussionmentioning

confidence: 99%

Evolutionary Silence of the Acid Chaperone Protein HdeB in Enterohemorrhagic Escherichia coli O157:H7

Carter

Louie

Fagerquist

et al. 2012

Appl Environ Microbiol

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The periplasmic chaperones HdeA and HdeB are known to be important for cell survival at low pH (pH < 3) in Escherichia coli and Shigella spp. Here we investigated the roles of HdeA and HdeB in the survival of various enterohemorrhagic E. coli (EHEC) following exposure to pH 2.0. Similar to K-12 strains, the acid protections conferred by HdeA and HdeB in EHEC O145 were significant: loss of HdeA and HdeB led to over 100-to 1,000-fold reductions in acid survival, depending on the growth condition of prechallenge cells. However, this protection was much less in E. coli O157:H7 strains. Deletion of hdeB did not affect the acid survival of cells, and deletion of hdeA led to less than a 5-fold decrease in survival. Sequence analysis of the hdeAB operon revealed a point mutation at the putative start codon of the hdeB gene in all 26 E. coli O157:H7 strains analyzed, which shifted the ATG start codon to ATA. This mutation correlated with the lack of HdeB in E. coli O157:H7; however, the plasmid-borne O157-hdeB was able to restore partially the acid resistance in an E. coli O145⌬hdeAB mutant, suggesting the potential function of O157-HdeB as an acid chaperone. We conclude that E. coli O157:H7 strains have evolved acid survival strategies independent of the HdeA/B chaperones and are more acid resistant than nonpathogenic K-12 for cells grown under nonfavorable culturing conditions such as in Luria-Bertani no-salt broth at 28°C. These results suggest a divergent evolution of acid resistance mechanisms within E. coli.

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“…However, this infectious dose is based on laboratory-grown cultures and may differ from the actual dose from natural transmission. One investigation of an outbreak in a Japanese prison estimated that the infectious dose in contaminated pickles was between 25 and 1,000 organisms (716).…”

Section: Epidemiologymentioning

confidence: 99%

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

et al. 2013

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SUMMARY Although Escherichia coli can be an innocuous resident of the gastrointestinal tract, it also has the pathogenic capacity to cause significant diarrheal and extraintestinal diseases. Pathogenic variants of E. coli (pathovars or pathotypes) cause much morbidity and mortality worldwide. Consequently, pathogenic E. coli is widely studied in humans, animals, food, and the environment. While there are many common features that these pathotypes employ to colonize the intestinal mucosa and cause disease, the course, onset, and complications vary significantly. Outbreaks are common in developed and developing countries, and they sometimes have fatal consequences. Many of these pathotypes are a major public health concern as they have low infectious doses and are transmitted through ubiquitous mediums, including food and water. The seriousness of pathogenic E. coli is exemplified by dedicated national and international surveillance programs that monitor and track outbreaks; unfortunately, this surveillance is often lacking in developing countries. While not all pathotypes carry the same public health profile, they all carry an enormous potential to cause disease and continue to present challenges to human health. This comprehensive review highlights recent advances in our understanding of the intestinal pathotypes of E. coli .

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Contamination level and ingestion dose of foodborne pathogens associated with infections

Cited by 115 publications

References 11 publications

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

High-Throughput Sequencing of Campylobacter jejuni Insertion Mutant Libraries Reveals mapA as a Fitness Factor for Chicken Colonization

Evolutionary Silence of the Acid Chaperone Protein HdeB in Enterohemorrhagic Escherichia coli O157:H7

Recent Advances in Understanding Enteric Pathogenic Escherichia coli

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