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Hirsch C.,University of Leipzig | Tegtmeyer N.,University College Dublin | Rohde M.,Helmholtz Center for Infection Research | Rowland M.,University College Dublin | And 2 more authors.
Journal of Gastroenterology | Year: 2012

Background: Many polymerase chain reaction (PCR)- based studies have shown that Helicobacter pylori DNA is prevalent in the oral cavity, but reports on the isolation of live bacteria are extremely rare. Thus, it is still unclear whether H. pylori can indeed survive in the oral environment. Methods: Here we used electron microscopy, selective growth techniques, urease assays, 16S rRNA PCR, and western blotting to investigate the possible presence of live H. pylori in 10 root canal and corresponding plaque samples of endodontic-infected deciduous teeth in three children. Results: Although H. pylori DNA was verifiable by PCR in several plaque and root canal samples, bacterial colonies could only be grown from two root canals, but not from plaque. These colonies were unequivocally identified as H. pylori by microscopic, genetic, and biochemical approaches. Conclusions: Our findings show that root canals of endodontic- infected teeth may be a reservoir for live H. pylori that could serve as a potential source for transmission. © Springer 2012. Source


Boehm M.,University College Dublin | Hoy B.,University of Salzburg | Rohde M.,Helmholtz Center for Infection Research | Tegtmeyer N.,University College Dublin | And 5 more authors.
Gut Pathogens | Year: 2012

Background: Campylobacter jejuni is one of the most important bacterial pathogens causing food-borne illness worldwide. Crossing the intestinal epithelial barrier and host cell entry by C. jejuni is considered the primary reason of damage to the intestinal tissue, but the molecular mechanisms as well as major bacterial and host cell factors involved in this process are still widely unclear. Results: In the present study, we characterized the serine protease HtrA (high-temperature requirement A) of C. jejuni as a secreted virulence factor with important proteolytic functions. Infection studies and in vitro cleavage assays showed that C. jejunis HtrA triggers shedding of the extracellular E-cadherin NTF domain (90 kDa) of non-polarised INT-407 and polarized MKN-28 epithelial cells, but fibronectin was not cleaved as seen for H. pyloris HtrA. Deletion of the htrA gene in C. jejuni or expression of a protease-deficient S197A point mutant did not lead to loss of flagella or reduced bacterial motility, but led to severe defects in E-cadherin cleavage and transmigration of the bacteria across polarized MKN-28 cell layers. Unlike other highly invasive pathogens, transmigration across polarized cells by wild-type C. jejuni is highly efficient and is achieved within a few minutes of infection. Interestingly, E-cadherin cleavage by C. jejuni occurs in a limited fashion and transmigration required the intact flagella as well as HtrA protease activity, but does not reduce transepithelial electrical resistance (TER) as seen with Salmonella, Shigella, Listeria or Neisseria. Conclusion: These results suggest that HtrA-mediated E-cadherin cleavage is involved in rapid crossing of the epithelial barrier by C. jejuni via a very specific mechanismusing the paracellular route to reach basolateral surfaces, but does not cleave the fibronectin receptor which is necessary for cell entry. © 2012 Boehm et al.; licensee BioMed Central Ltd. Source


Particular aspects provide a method of sampling, testing and validating test lots (e.g., single-unit production lots), comprising: assembling a plurality of product portions from each of a plurality of test lots and combining the collected product portions to provide a corresponding set of test lot samples (wherein each test lot sample is attributed to a particular corresponding test lot); enriching the set of test lot samples; removing equal portions of each enriched sample, and combining the removed portions to provide a modular composite sample; and testing of the modular composite sample for the target agent/organism, wherein where such testing is positive, individual test lots may nonetheless yet be validated by further testing of a respective enriched test lot sample and obtaining a negative test result. The methods have broad utility for monitoring all sorts of test lots (e.g., environmental lots, production lots, pharmaceutical lots, etc.) and for efficiently affecting informed, targeted remedial measures.


Particular aspects provide a method of sampling, testing and validating test lots (e.g., single-unit production lots), comprising: assembling a plurality of product portions from each of a plurality of test lots and combining the collected product portions to provide a corresponding set of test lot samples (wherein each test lot sample is attributed to a particular corresponding test lot); enriching the set of test lot samples; removing equal portions of each enriched sample, and combining the removed portions to provide a modular composite sample; and testing of the modular composite sample for the target agent/organism, wherein where such testing is positive, individual test lots may nonetheless yet be validated by further testing of a respective enriched test lot sample and obtaining a negative test result. The methods have broad utility for monitoring all sorts of test lots (e.g., environmental lots, production lots, pharmaceutical lots, etc.) and for efficiently affecting informed, targeted remedial measures.


Patent
Institute for Environmental Health Inc. | Date: 2015-01-15

Aspects of the present invention provide novel multi-targeted microbiological screening and monitoring methods having substantial utility for monitoring and control of microbial growth and contaminants, microbiological processes, predictive microbiology, and for exposure and risk assessment. Microbial markers shared by both target and index microbes are used in novel methods for microbial monitoring, monitoring of microbial performance potential, trend analysis, and statistical process control (SPC) in processes or systems that are receptive to a plurality of genetically distinct microbes.

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