Correlation Between Avian PathogenicSpore Load and Occurrence of Necrotic Enteritis on Broiler Chicken Farms.

Abstract

Necrotic enteritis (NE) is a significant intestinal disease in poultry caused by the spore-forming, obligate anaerobe. Historically, antimicrobials have controlled NE but growing concerns over antibiotic resistance have led to reduced use, resulting in disease resurgence.spores persist in poultry environments, and their accumulation is believed to contribute to NE outbreaks. However, tools to assess spore load and predict outbreak risk are limited. To address this, a selective egg yolk agar medium was developed using potassium chlorate to inhibit aerobic bacteria, combined with heat treatment to enumeratespores in poultry litter. Matrix-assisted laser desorption-ionization time of flight mass spectrometry confirmed that 80% of lecithinase-positive colonies on chlorate-supplemented agar were. When comparing reinforcedagar andagar (CPA) as bases, chlorate did not significantly reduce lecithinase-positive aerobes. Ninety-nine percent of lecithinase-positive black colonies on CPA were strict anaerobes, and 85% were confirmed asby PCR. A significant correlation (&#x3c7;test;< 0.05) was observed between spore abundance in litter and a farm's NE history. However, spore abundance did not correlate with increased sporulation efficiency inisolates (= 0.86). Notably, the presence of-positivewas strongly associated with prior NE outbreaks (< 0.01). This study demonstrated CPA-based egg yolk agar as an effective diagnostic medium for detectingin poultry litter.