Jean-Pierre HERNALSTEENS

The Viral Genetics research group investigates the molecular basis of the interaction of pathogenic bacteria (Escherichia coli, Salmonella enterica, Staphylococcus aureus and Campylobacter jejuni) of humans and domestic animals with their host. The research is facilitated by the new high-performance methods for analysis of bacterial and bacteriophage genome sequences. An alarming increase of the antibiotic resistance of pathogenic bacteria is observed worldwide, therefore alternative methods for the prevention and treatment of bacterial infections of humans and farm animals are developed and tested. These studies are performed in close collaboration with external partners, who have the necessary complementary expertise.

• The research group produced efficient live Salmonella vaccine strains with well-defined deletion mutations for the protection of chickens against Salmonella infections.
• Bacteriophages, viruses that infect and kill pathogenic bacteria, are isolated, characterized genetically and tested as alternatives for antibiotics. In vivo tests on the use of bacteriophage therapy for the protection of chickens against infection by avian pathogenic Escherichia coli strains allowed the identification of difficulties that must be solved before the technique can be applied successfully in veterinary practice.
• The production of biofilms, consisting of bacterial cells imbedded in a matrix of various polymers, protects these bacteria against antibiotics and disinfectants and also against the immune system of the host. Comparison of the genome sequences of wild type clinical methicillin resistant Staphylococcus aureus isolates, with a strikingly different capacity produce biofilms, allowed the identification of candidate genes involved in the regulation of in vivo biofilm formation. The role of these genes can subsequently be evaluated after inactivating them in the same strain.
• Nanobodies are the antigen-binding domains of heavy-chain antibodies of Camelidae. The use of these small and very stable proteins to protect chickens against colonisation by Campylobacter jejuni is evaluated.

Sabirova JS, Hernalsteens JP, De Backer S, Xavier BB, Moons P, Turlej-Rogacka A, De Greve H, Goossens H, Malhotra-Kumar S. Fatty acid kinase A is an important determinant of biofilm formation in Staphylococcus aureus USA300. BMC Genomics. 2015; 16: 861.

Song N, Xu J, Li Z, Hernalsteens JP. Curing a large endogenous plasmid by single substitution of a partitioning gene. Plasmid. 2015; 82: 10-6.

Tsonos J, Vandenheuvel D, Briers Y, De Greve H, Hernalsteens JP, Lavigne R. Hurdles in bacteriophage therapy: deconstructing the parameters. Vet Microbiol. 2014; 171: 460-9

Tsonos J, Oosterik LH, Tuntufye HN, Klumpp J, Butaye P, De Greve H, Hernalsteens JP, Lavigne R, Goddeeris BM. A cocktail of in vitro efficient phages is not a guarantee for in vivo therapeutic results against avian colibacillosis. Vet Microbiol. 2014; 171: 470-9.

Tsonos J, Adriaenssens EM, Klumpp J, Hernalsteens JP, Lavigne R, De Greve H. Complete genome sequence of the novel Escherichia coli phage phAPEC8. J Virol. 2012; 86: 13117-8.

Li Z, Bouckaert J, Deboeck F, De Greve H, Hernalsteens JP. Nicotinamide dependence of uropathogenic Escherichia coli UTI89 and application of nadB as a neutral insertion site. Microbiology. 2012; 158: 736-45.

Van Gerven N, Derous V, Hernalsteens JP. Expression of in vivo-inducible Salmonella enterica promoters during infection of Caenorhabditis elegans. FEMS Microbiol Lett. 2008; 278: 236-41.

Sadeghi A, Broeders S, De Greve H, Hernalsteens JP, Peumans WJ, Van Damme EJ, Smagghe G. Expression of garlic leaf lectin under the control of the phloem-specific promoter Asus1 from Arabidopsis thaliana protects tobacco plants against the tobacco aphid (Myzus nicotianae). Pest Manag Sci. 2007; 63: 1215-23.

Sadeghi A, Smagghe G, Broeders S, Hernalsteens JP, De Greve H, Peumans WJ, Van Damme EJ. Ectopically expressed leaf and bulb lectins from garlic (Allium sativum L.) protect transgenic tobacco plants against cotton leafworm (Spodoptera littoralis). Transgenic Res. 2008; 17: 9-18.

Adriaensen C, De Greve H, Tian JQ, De Craeye S, Gubbels E, Eeckhaut V, Van Immerseel F, Ducatelle R, Kumar M, Hernalsteens JP. A live Salmonella enterica serovar Enteritidis vaccine allows serological differentiation between vaccinated and infected animals. Infect Immun. 2007; 75: 2461-8.