Genetic Diversity of Clostridium perfringens Strains Isolated from Broiler Chickens Revealed by PFGE Analysis in China and Pakistan.

Clostridium perfringens (C. perfringens) is widely distributed in broiler chickens causing clinical and subclinical enteritis and is especially known for causing necrotic enteritis (NE). There are numerous reports of NE outbreaks in Pakistan as well as China but there is a lack of information related to PFGE profile from both the countries. To close this gap, we designed this study and obtained samples from broiler chicken farms located in 3 different regions of Pakistan and 4 different regions of China. A total of 79 fecal swabs (Pakistan=29; China=50) were collected and grown on FTA media. Further, isolates were grown on TSE agar and black colonies were selected for DNA extraction. All 79 isolates were tested for toxin profiles by PCR (a-gene; beta-2; netB gene) and PFGE profiling (pulsotypes analysis). Toxinotyping results revealed that all the isolates (n=50) from China were type A (a-toxin positive) while 23 and 6 isolates (n=29) from Pakistan were type A (a-toxin positive) and type G (a-toxin, NetB positive), respectively. Toxinotyping revealed a-toxin is highly prevalent in both the countries while from Pakistani isolates, NetB toxin was also detected. PFGE discriminated 79 isolates into 45 different PFGE patterns (pulsotypes). The analysis further showed different pulsotypes originating from China and Pakistan and isolates were subtyped by SmaI. The results showed high genetic polymorphism in C. perfringens even within the same strain. These preliminary findings of genetic variations will further help to design control strategies. [ABSTRACT FROM AUTHOR]