Biology subjects

Nasher, F.

Publications and source records attributed to Nasher, F..

3 recordsLinked to original sources

bioRxiv2023

Understanding Campylobacter coli isolates from the Vietnamese meat production network; a pilot study

Changing farming practices and the associated increase in the use of antibiotics are amongst the main drivers shaping the global increase of Campylobacter infections. The effects farming practices have on Campylobacter species, need to be studied at the global scale, particularly in emerging middle-income countries, where the demand for low-cost poultry meat is rising. While C. jejuni causes the majority of poultry associated diarrhoea, C. coli causes a significant amount of disease but are relatively understudied. In this study we characterised seven C. coli strains isolated from poultry farms and markets in Hanoi, Vietnam. Comprehensive data sets of bacterial Whole-Genome Sequencing; and phenotypic assays, such as, growth, motility, antimicrobial resistant testing along with virulence testing were performed to reveal the genetic relatedness and pathophysiological characteristics of seven C. coli strains. Six isolates were classified as multi-drug resistant, with all isolates resistant to ciprofloxacin, nalidixic acid and tetracycline, but susceptible to phenicols. All isolates had similar growth rates, while five were hyper-motile. Lethality of the isolates towards a tractable host-model system, larvae of the greater wax moth Galleria mellonella, often used to determine Campylobacter virulence was demonstrated for the first time for C. coli. Multilocus sequence typing data correlates with North American, European, and Asian isolates from patients suffering from gastroenteritis, emphasising the global spread of these strains. This work demonstrates that C. coli, with high levels of antimicrobial resistance, is an understudied global threat. Data summaryGenBank database with accession numbers JAKGTW000000000, JAKGTV000000000, JAKGTS000000000, JAKGTU000000000, JAKGTT000000000, JAKGTR000000000 and CP091310 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTW000000000 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTV000000000 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTS000000000 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTU000000000 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTT000000000 https://www.ncbi.nlm.nih.gov/nuccore/JAKGTR000000000 https://www.ncbi.nlm.nih.gov/nuccore/CP091310.1 The authors confirm all supporting data, code and protocols have been provided within the article or through supplementary data files.

microbiology↗

bioRxiv2022

Survival of Campylobacter jejuni in Acanthamoebae castellanii provides mechanistic insight into host pathogen interactions.

Campylobacter jejuni is the leading cause of bacterial foodborne gastroenteritis world-wide but is rarely transferred between human hosts. Although a recognized microaerophile, C. jejuni is incapable of growing in an aerobic environment. The persistence and transmission of this pathogen outside its warm-blooded avian and mammalian hosts is poorly understood. Acanthamoebae species, are predatory protists and form an important ecological niche with several bacterial species. Here, we investigate the interaction of C. jejuni and Acanthamoebae castellanii at the single-cell level. We observe that a subpopulation of C. jejuni cells can resist killing by A. castellanii and non-digested bacteria are released into the environment where they can persist. In addition, we observe that A. castellanii can harbor C. jejuni even upon encystment. Transcriptome analyses of C. jejuni interactions revealed similar survival mechanisms when infecting both A. castellanii and warm-blooded hosts. In particular, nitrosative stress defense mechanisms and flagellum function are important as confirmed by mutational analyses. This study describes a new host-pathogen interaction for C. jejuni and confirms that amoebae are transient hosts for the persistence, adaptability and potential transmission of C. jejuni.

microbiology↗

bioRxiv2021

Survival of Campylobacter jejuni in Amoebae enhances subsequent invasion of mammalian cells

The ubiquitous unicellular eukaryote, Acanthamoeba, is known to play a role in the survival and dissemination of Campylobacter jejuni. C. jejuni is the leading cause of bacterial foodborne gastroenteritis world-wide and is a major public health problem. The ability of C. jejuni to interact and potentially invade epithelial cells is thought to be key for disease development in humans. We examined C. jejuni grown under standard laboratory conditions,11168HCBA with that harvested from within Acanthamoeba castellanii (11168HAC/CBA) or Acanthamoeba polyphaga (11168HAP/CBA), and compared their ability to invade different cell lines. C. jejuni harvested from within amoebae had a [~]3.7-fold increase in invasiveness into T84 human epithelial cells and a striking [~]11-fold increase for re-entry into A. castellanii cells. We also investigated the invasiveness and survivability of six diverse representative C. jejuni strains within Acanthamoeba spp., our results confirm that invasion and survivability is likely host cell dependent. Our survival assay data led us to conclude that Acanthamoeba spp. are a transient host for C. jejuni and that survival within amoebae pre-adapts C. jejuni and enhances subsequent cell invasion. This study provides new insight into C. jejuni interactions with amoebae and its increased invasiveness potential in mammalian hosts.

microbiology↗