Bovine abortion associated with staphylococcus aureus infection – characterization of s. Aureus strain isolated from fetal tissues

Abstract

Staphylococcus aureus is a gram-positive bacterium, commonly found colonizing the skin and mucous membranes of humans and animals. This report describes a case of fetal loss associated with S. aureus infection in a cow. A six-month old, crossbred male bovine fetus from a beef farm was submitted for necropsy. At gross examination fibrinous pleuropneumonia was observed. Histologically, lesions were restricted to the lungs and consisted of marked multifocal to coalescing areas of inflammatory infiltrate of neutrophils, abundant fibrin exudation, necrosis of bronchiolar epithelium and numerous aggregates of coccoid bacteria. Lung and abomasal fluid bacterial culture yielded pure culture of S. aureus, which was characterized as a multidrug resistant strain. Molecular analysis indicated that the studied strain presented several genes of virulence factors including toxic shock syndrome toxin-1 (tst), staphylococcal enterotoxin type A (sea), Panton– Valentine leukocidin (pvl), alpha-hemolysin (hla) and delta-hemolysin (hld). This report documents an infrequent case of fetal loss in cattle due to infection with a highly virulent S. aureus strain.