Biology subjects

Mou, K.

Publications and source records attributed to Mou, K..

3 recordsLinked to original sources

bioRxiv2022

Phenotypic and genomic comparison of human outbreak and cattle-associated Shiga toxin-producing Escherichia coli O157:H7

Escherichia coli O157:H7 (O157)-adulterated food products, including beef and produce, are associated with disease outbreaks in humans. Although cattle feces are a source for the contamination, it is unclear if diverse O157 human-associated outbreak isolates expressing a specific virulence phenotype can colonize and shed in the feces of cattle at a quantitatively similar levels to non-outbreak isolates. It is also unclear if other phenotypes, such as biofilm, cell attachment, and toxin production, differentiate environmental O157 isolates from O157 isolates associated with human illness. Genomic profiling of O157 isolates acquired through routine surveillance can inform if the isolates encode virulence genes associated with human disease, but many genotype-phenotype relationships remain unclear for O157. Therefore, the objective of this study was to compare a diverse set of O157 isolates, with the intent of identifying potential genotypic differences that could inform phenotypes such as cattle colonization and fecal shedding, in vitro cell attachment, biofilm production, and Shiga toxin production. In addition, the relationship between phenotypes and potential for foodborne illness as it relates to genomic virulence traits was explored. No significant differences in cattle colonization and fecal shedding were detected for the tested isolates, despite broad genomic differences. In addition, the in vitro phenotypic differences noted in biofilm and cell attachment did not associate with one LSPA-6 lineage compared to another. Overall, no differences in cattle shedding were observed, yet variations in genotype and phenotype were identified indicating further work is warranted to better understand the relationship between O157 genome and virulence. ImportanceFoodborne illness has a major impact on the health and wellbeing of the global population, besides creating substantial financial hardships for industry. While many bacteria and viruses are implicated in foodborne illness, Escherichia coli serotype O157:H7 (O157) is a common food adulterant that can cause human disease and food recalls. Cattle feces are a significant source of food-adulterating O157. A greater understanding of O157 genetics and its relation to phenotype is needed to develop mitigation strategies to limit spread of O157 into the food chain. The goal of the research was to identify O157 genomic and phenotypic attributes of O157 associated with cattle colonization and fecal shedding along with other factors involved in environmental persistence and illness in humans. It was observed that variations in biofilm formation and in vitro cellular adherence did not associate with enhanced cattle colonization or fecal shedding, indicating that the processes involved in cattle colonization are complex and not well understood.

microbiology↗

bioRxiv2022

Route of oxytetracycline administration differentially impacts the growth and gut microbiome of pigs co-infected with Bordetella bronchiseptica and Pasteurella multocida

Along with judicious antibiotic use, there is great interest in how the dose regimen of an antibiotic affects the animal gut microbiota. This study evaluated the impact of experimental respiratory infection alone or respiratory infection followed by oxytetracycline (oxytet) treatment on the animals health and its fecal microbiome. Piglets of approximately three weeks-of-age were separated into four groups (n=20 per group). One group remained non-infected and administered non-medicated feed and the other three groups were infected with Bordetella bronchiseptica (day 0) and Pasteurella multocida (day 4), with one group receiving non- medicated feed and the remaining two groups receiving oxytetr starting on day 7 by injection or in-feed (day 7-14). Infection with B. bronchiseptica and P. multocida negatively impacted piglet growth and induced mild pneumonia. Infection alone had minimal effect on the fecal microbiota community. When oxytet was administered either by injection or in-feed to treat the respiratory infections, both routes had minimal effect on clearing B. bronchiseptica and P. multocida in the animal. However, both routes appeared to limit lung lesion severity, and injected oxytet reduced the negative impact of infection on weight gain. Both routes had limited impact on the animals overall gut microbiome, including relative abundances of bacterial taxa and antibiotic resistance genes tet32, tetW, and aph2. Overall, oxytet administered by either route did not clear the respiratory infection, but oxytet administration minimized the negative health impacts of infection and had minor impact on the pig gut microbiome. ImportanceEfforts to address antibiotic resistance calls for improved antibiotic stewardship, including considering antibiotic administration route. While our previous study found in-feed oxytet had greater impact on the gut microbiome of healthy piglets than injected oxytet, it remained unknown if oxytet treatments would have the same impact on the microbiota of infected piglets. We evaluated the impact of respiratory infection alone or respiratory infection followed by oxytet treatment on the animals health and their gut microbiome profile. Respiratory infection negatively affected piglets health, but infection alone had minimal impact on the gut community. When oxytet was administered either in-feed or by injection to treat the respiratory infection, neither route of administration led to the clearance of the respiratory pathogens. However, oxytet minimized the negative health impacts of infection, and had minor impact on the pig gut microbiome. These findings are informative for disease management in food animals while integrating antibiotic stewardship practices.

microbiology↗

bioRxiv2020

Small non-coding RNA CjNC110 influences motility, autoagglutination, AI-2 localization, and chicken colonization in Campylobacter jejuni

Small non-coding RNAs are involved in many important physiological functions in pathogenic microorganisms. Previous studies have identified the presence of non-coding RNAs in the major zoonotic pathogen Campylobacter jejuni, however, few have been functionally characterized to date. CjNC110 is a conserved ncRNA in C. jejuni, located downstream of the luxS gene which is responsible for the production of the quorum-sensing molecule autoinducer-2 (AI-2). In this study, we utilized strand specific high-throughput RNAseq to identify potential targets or interactive partners of CjNC110 in a sheep abortion clone of C. jejuni. This data was then utilized to focus further phenotypic evaluation of the role of CjNC110 in motility, autoagglutination, quorum sensing, hydrogen peroxide sensitivity and chicken colonization in C. jejuni. Inactivation of the CjNC110 ncRNA led to a statistically significant decrease in autoagglutination ability as well as increased motility and hydrogen peroxide sensitivity when compared to wild-type. Extracellular AI-2 detection was decreased in {Delta}CjNC110, however, intracellular AI-2 accumulation was significantly increased, suggesting a key role of CjNC110 in modulating the transport of AI-2. Notably, {Delta}CjNC110 also showed a decreased ability to colonize chickens. Complementation of CjNC110 restored all phenotypic changes back to wild-type levels. The collective results of the phenotypic and transcriptomic changes observed in our data provide valuable insights into the pathobiology of C. jejuni sheep abortion clone and strongly suggest that CjNC110 plays an important role in regulation of energy taxis, flagellar glycosylation, cellular communication via quorum sensing, oxidative stress tolerance and chicken colonization in this important zoonotic pathogen.

microbiology↗