Necrohemorrhagic Pneumonia From Extraintestinal Pathogenic Escherichia coli (ExPEC) in Federal Government-Owned Dogs: A Case Series.

INTRODUCTION

Escherichia coli is a common gastrointestinal commensal organism. Certain strains, termed extra-intestinal pathogenic E. coli (ExPEC), possess virulence factors that cause disease outside of the intestines. ExPEC can cause necrohemorrhagic pneumonia in dogs, almost all previous reports of which are in research animals with a recent travel history. This is the first report of ExPEC pneumonia in non-laboratory, kenneled dogs and federal government-owned dogs, none of which had a recent travel history.

MATERIALS AND

METHODS

Between October 2021 and April 2024, four government-owned dogs from one kennel.

RESULTS

Developed peracute, rapidly progressive respiratory distress and lethargy. They were neutropenic (n = 4) with prolonged clotting times (n = 3); thoracic imaging revealed multilobar alveolar to interstitial pulmonary patterns (n = 4), pleural effusion (n = 3), and pneumothorax (n = 2). All were euthanized or died between 3 hours and 3 days after clinical presentation. At necropsy, the lungs were deep red-purple and firm (n = 4), the thorax contained hemorrhagic pleural effusion (n = 3), and hemorrhage was noted in the endocardium (n = 2), meninges (n = 1), and gastric lumen (n = 1). Aerobic lung culture (n = 4) yielded E. coli; two isolates were multi-drug resistant, including to most or all tested beta-lactams (n = 2) and amikacin (n = 1). Histologically, pulmonary alveoli and bronchioles were filled with hemorrhage, fibrin, edema, neutrophils, necrotic debris, and 1-2 µm, gram negative bacilli. Cytotoxic necrotizing factor-1 was detected with polymerase chain reaction (n = 1).

CONCLUSIONS

Consistent with necrohemorrhagic pneumonia caused by ExPEC. Although ExPEC pneumonia does not appear transmissible, ExPEC strains are transmissible between animals and people. Further studies are needed to clarify the epidemiologic significance of this disease.