Investigating zoonotic pathways: non-Helicobacter pylori Helicobacter species in raw meat products sold for human consumption in the UK.
Project Summary
The primary hosts of non-Helicobacter pylori Helicobacter (NHPH) species are domesticated and farmed animals[1]. NHPH species have been associated with animal host diseases such as gastritis (inflammation), gastric ulceration and reduced slaughter weight compared to uninfected animals[2-3]. Some NHPH species are zoonotic having been isolated from human gastric biopsies[1]. Disease manifestations such as gastritis, gastric ulcer disease, MALT lymphoma and gastric adenocarcinoma have been recorded in humans infected with NHPH species[3]. Despite the importance of these animal and human gastric pathogens, it is not well known how these species transmit from animals to humans. Other zoonotic bacterial pathogens have been isolated from contaminated raw meat products sold in the UK. One such example is Campylobacter jejuni which is a gut commensal of poultry and has been isolated from contaminated poultry products sold in UK supermarkets[4]. Outbreaks of campylobacterosis have been linked to poultry products, raw milk and poor food preparation/hygiene practices, highlighting zoonotic transmission networks to humans[5]. However, zoonotic routes of infection by NHPH species are not well defined. Some studies have suggested raw meat products as a potential reservoir of human infection but there have been few studies to support this theory[6].
The project will employ culture (selective growth media) and culture-free (PCR) methodologies to determine if NHPH species can be identified in raw meat products sold in the UK. The primary focus will be identification of Helicobacter suis, primarily found in pigs, as this species is the predominant NHPH species isolated from human gastric biopsies. Multi-locus sequence typing (MLST) will be carried out on H. suis positive samples which will be analysed to identify potential transmission links (through sequence types) from H. suis identified from raw meat. These will be compared to existing isolates from human and animal origin in the PubMLST database (https://pubmlst.org/organisms/helicobacter-suis) using freely available online tools.
This ambitious but achievable 9.5-week project will add to our understanding of how NHPH species are transmitted to humans from animals. The successful candidate will identify raw food products for sale on the UK high streets (for example, supermarkets and butchers) for microbiological evaluation, speciation through PCR and MLST analysis. An understanding of some of the techniques involved in this study would be advantageous.
References:
1. Haesebrouck F, et al. Gastric Helicobacters in domestic animals and nonhuman primates and their significance for human health. 2009. doi: 10.1128/CMR.00041-08.
2. De Witte C, Ducatelle R and Haesebrouck F. The role of infectious agents in the development of porcine gastric ulceration. 2018. doi: 10.1016/j.tvjl.2018.04.015.
3. Taillieu E, et al. Gastric Helicobacter species associated with dogs, cats and pigs: significance for public and animal health. 2022. doi: 10.1186/s13567-022-01059-4.
4. Public Health England. A microbiological survey of Campylobacter contamination in fresh whole UK-produced chilled chickens at retail sale (Y5). Food Standards Agency. 2021. doi: https://doi.org/10.46756/sci.fsa.xls618.
5. Kaakoush NO, et al. Global Epidemiology of Campylobacter Infection. 2015. doi: 10.1128/CMR.00006-15.
6. Rimbara E, et al. Isolation and characterization of Helicobacter suis from human stomach. 2021. doi: 10.1073/pnas.
Training: There are several training opportunities for the successful candidate. The candidate will learn how to culture fastidious bacteria from food samples using selective media. Training on microscopy and the Gram staining of bacteria will be provided. Additionally, the candidate will learn how to perform PCR to detect bacteria without the need for culture and how to carry out PCR amplification of genes required for multi-locus sequence typing (MLST). Consequently, the candidate will be trained on how to carry out MLST and multi-locus sequence analysis using freely available online tools. The candidate will be trained on how to maintain a good laboratory diary. Finally, the candidate will be supported with any written outputs associated with this position such as laboratory reports and/or publications (if the work is deemed publishable in a suitable journal such as Access Microbiology). This support will be offered to the successful candidate beyond the duration of the project by the PI.