Pasteurella multocida can cause serious infections after dog or cat bite. We report here a rare case of hand infection caused by P. multocida consecutive to an injury by a thorn of the prickly pear. It caused an amputation of the distal phalanx of the thumb in a trisomic patient. It is about a 27-year-old man who was admitted to the hospital with swelling and intense pain of the left hand. He reported a sting by a thorn of prickly pear 15 days before. The patient was admitted to proceed with operative irrigation and debridement. The pus was collected for microbiological examination. Microscopic examination after Gram staining revealed small Gram-negative coccobacilli, associated to polymorphonuclear reaction. Culture have objectivated Pasteurella multocida. The isolated strain was susceptible to betalactamins. Patient was treated with ampicillin. Well-conducted antibiotics and repetitive local cares have not prevented local lesions from progressing to necrosis of the soft parts of the thumb and osteitis of the distal phalanx of the thumb. The patient underwent a necrosectomy and an amputation of the distal phalanx. Ampicillin was replaced by amoxicillin/clavulanic acid and after 15 days, progression was clinically and microbiologically favorable. In the case we report, since the patient does not report any exposure or contact with animals, the thorn prick is the source of infection. It was contaminated from the animal reservoir. Taking into account the monomicrobism of the infection, treatment with aminopenicillins was sufficient. Our propositus came to the hospital 15 days after the inoculation of the bacterium. This duration appears to be very late in relation to the acute character of pasteurellosis. This was probably the main reason why the local infection evolved towards osteoarticular complications. That's why, we should consider Pasteurella multocida in case of infection by inoculation, even in the absence of contact with the animals.
Keywords: Amputation; Bites and stings; Infection; Osteitis; Pasteurella multocida.