Evaluating the environmental survivability of Mannheimia haemolytica on various potential fomites

Bovine respiratory disease (BRD) is an important cause of morbidity and mortality in beef and dairy cattle in North America. Of the significant bacteria implicated in BRD cases, Mannheimia haemolytica is the most common microbe isolated in clinical cases, yet little is known about its environmental survivability. The objective of this study was to examine relative survivability of M. haemolytica on metal, wood, and plastic under varying environmental conditions. Microenvironments were constructed at approximately 37℉ (3℃), 71℉ (22℃), and 97℉ (36℃) using plastic containers and monitored for temperature and humidity. Stainless steel, polypropylene, and wood spheres were inoculated with M. haemolytica, placed in each microenvironment, and cultured for viable bacteria at 0, 2, 6, 24, and 48 h after inoculation. Presence or absence of growth of M. haemolytica was confirmed by MALDI-TOF mass spectrometry. Both wood and plastic materials supported the recovery of viable bacteria for a much longer duration than stainless steel. Additionally, increased temperature and decreased humidity lowered bacterial viability. These results demonstrate that both material and environment are factors related to M. haemolytica survival, which has potential biosecurity implications when managing BRD in beef and dairy operations.