Pasteurella multocida Infections with Unusual Modes of Transmission from Animals to Humans: A Study of 79 Cases with 34 Nonbite Transmissions

Pasteur discovered the causative agent of fowl cholera (Pasteurella multocida) in 1880. Since then, multiple zoonotic infections affecting humans have been reported. P. multocida infections usually result from bites of cats or dogs. The earliest reports of nonbite transmissions (NBTs) were attributed to cat scratches and lung colonization. More recently, multiple modes of unusual NBTs have been reported, including animal exposures with no direct contact. Here, we report 79 cases of pet-associated infections, with 34 NBTs. Previously unreported and unsuspected, novel modes of NBTs presented include stepping on dog drool infecting a submetatarsal ulcer, contamination of a wound by socks covered with cat hair and dander resulting in P. multocida bacteremia, stumbling over a dog and falling while drunk and abrasions contaminated with dog saliva resulting in wound infection, and severe epiglottitis and supraglottitis after eating peanut butter and crackers half eaten by a dog. Cat bites were more common than dog bites. Both bite and nonbite infections were more common in the elderly, with more older patients in the nonbite group. Upper extremity bites were more than lower extremity bites for both cats and dogs. NBTs were associated with more co-morbidities and resulted in more life-threatening infections than bites, confirming the findings of a prior smaller series. Open wounds were the most common point of entry for nonbite infections, with majority in the lower extremity. Based on this study and prior reports, pet owners must protect open wounds and individuals with certain underlying conditions and infants should avoid pet exposure completely. Our findings and animal transmission of bite and nonbite P. multocida infections reported in literature are summarized.