Clinical features of pasteurellosis without an animal bite or scratch in comparison with bite/scratch pasteurellosis

Pasteurellosis is a common zoonotic infection that occurs after an animal bite or scratch (B/S). We compared the clinical features of six patients with non-B/S pasteurellosis with those of 14 patients with B/S infections. Pasteurella multocida was identified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in all six non-B/S infections, whereas 13 of the 14 B/S infections were identified with diagnostic kits. The non-B/S infections were pneumonia (n = 3), skin and soft tissue infections (n = 2), and bacteremia (n = 1). Pneumonia occurred in two patients with underlying pulmonary disease, whereas ventilator-associated pneumonia developed in one patient with cerebral infarction. Pasteurella multocida was isolated from a blood specimen and nasal swab from a patient with liver cirrhosis (Child-Pugh class C) and diabetes. Cellulitis developed in one patient with diabetes and normal-pressure hydrocephalus, who had an open wound following a fall, and in one patient with diabetes and a foot ulcer. Three patients with non-B/S infections had no pet and no episode of recent animal contact. The rate of moderate-to-severe comorbidities was significantly higher in patients with non-B/S infections than in those with B/S infections (100% and 14.3%, respectively, p < 0.001). In conclusion, non-B/S infections can develop in patients with chronic pulmonary disease, invasive mechanical ventilation, or open wounds, or who are immunocompromised, irrespective of obvious animal exposure. In contrast to B/S infections, non-B/S pasteurellosis should be considered opportunistic.