Abstract

Necrotic enteritis is a multifactorial, complex disease that is prevalent within the
poultry industry, subsequently costing US$6 billion, annually. The number of emerging
cases has increased in recent years, attributed to the ban of antibiotic growth
promoters. Necrotic enteritis is caused by the NetB toxin of Clostridium perfringens,
however, the specific role of this toxin in the induction of disease is often disputed.
The aim of this study was to phenotypically characterise isolates of C. perfringens,
originating from UK sourced poultry of varying disease statuses, in an attempt to
identify characteristics that may predict the potential virulence in vivo. Within this
study, the phenotypic analysis involved the investigation of growth kinetics, biofilm
production and haemolysis capability. The semi in vivo analysis of isolates utilised the
Galleria mellonella larval model to identify whether phenotypic analysis would
accurately represent virulence. This study demonstrated the effective use of rapid, cost
effective assays to phenotypically characterise isolates of C. perfrignens. Significant
differences (p<0.05) were identified in biofilm formation and G. mellonella morbidity,
between isolates originating from commensal and clinical origins. The results of this
study established that isolates of identical toxin types are able to produce varying
phenotypic profiles, further highlighting the importance of characterisation in this
manner.