Testing of phage activity against Clostridium perfringens LMG 11264 within a complex chicken cecal microbiota in vitro

Clostridium perfringens causes foodborne illness worldwide, and 95% of human infections are linked to the consumption of contaminated meat, including chicken products. In poultry, C. perfringens may cause necrotic enteritis, and infections are associated with high mortality rates. The strains of this bacterium may harbor a repertoire of antibiotic resistance, hampering the efficient treatment of infections. In vitro screening approaches of alternative treatment options, for instance with specific phages represent a promising strategy for the selection of novel interventions to combat infections. In this study, we explored the application of a C. perfringens strain LMG 11264 specific phage #7 introduced at 104 PFU/mL for the inhibition of C. perfringens growth at 106 CFU/ml next to two antibiotics (amoxicillin 10 µg/ml and clindamycin at 10 µg/ml) within complex chicken cecal microbiota in vitro. Samples for gDNA isolation, qPCR, and metagenome sequencing were taken after 24 and 48 hours of incubation. The C. perfringens LMG 11264 proliferated within the untreated complex microbiota and reached levels of about 5 x106 and 2 x 107 genome equivalents per mL after 24 and 48 hours of incubation, respectively. The phage intervention with the Phage #7 inhibited the growth of the spiked C. perfringens significantly, the inhibitory effects were similar to those exerted by the antibiotic interventions though with lesser disturbance of the microbial diversity as reflected by the alpha and beta diversity indices. Our in vitro screening approach facilitates the screening of novel phages and treatments against C. perfringens with increased experimental flexibility and throughput and hence inherent potential also for the exploration of combination therapies for optimal health outcomes.