Pasteurella multocida chest wall abscess without wounds

A 79-year-old Japanese man presented to our hospital with an 18day history of fever and right-sided chest pain. The patient had undergone surgery for rectal cancer 2 years previously. Although he had three pet cats in his home, he had no history of cat bites, scratches, or licks. On examination, his blood pressure was 92/57 mmHg and temperature was 37.1 °C; a soft subcutaneous mass without obvious wounds was noted in the right-sided chest (Fig. 1). Laboratory data revealed leukocytosis (33.3 × 10/μL with 94.5% neutrophils) and elevated C-reactive protein levels (11.7 mg/dL). On admission, contrast-enhanced computed tomography revealed a subcutaneous multilocular abscess in the right-sided chest (Fig. 2). Piperacillin–tazobactam (4.5 g every 8 h) was empirically administered, and surgical drainage was performed. Although the abscess culture grew Pasteurella multocida, the two sets of blood cultures obtained on admission grew no microorganisms. Based on the results of susceptibility tests, the antimicrobial therapy was changed to ampicillin–sulbactam (3 g every 6 h). The patient was discharged on day 22, and the antimicrobial therapy was changed to oral amoxicillin (750 mg/day). After a 9-week antimicrobial course, the patient recovered without any obvious sequelae. P. multocida is a non-motile, facultatively anaerobic, gram-negative coccobacillus, which is a part of the microbiota of domesticated and wild animals (particularly cats and dogs) [1]. It can cause human infections, generally as a result of cat and dog bites, scratches, and licks [2]. However, our patient had no such animal contact. This case highlights that P. multocida infections can occur without bites, scratches, or licks. Although noting the history of animal contact is important, physicians should be aware of the potential risk of P. multocida infections in cat and dog owners without a history of such contact. Fig. 1. Photograph taken on admission, which shows a subcutaneous mass in the rightsided chest.