A group of 16 male pallid bats (Antrozous pallidus) was collected from the wild in central Texas in May of 2010 for the purpose of display. Case #1 was an adult male, presented January 2011, with a swollen discolored area one centimeter in diameter on the chest. The bat was examined under general anesthesia. Four swellings identified over the chest and ventrum were biopsied, cultured, opened, and flushed. No physical exam findings of external injuries to explain the abscesses were identified. Treatment with systemic antibiotics was initiated. Routine aerobic, anaerobic, and fungal cultures were negative. Five acid fact bacilli were identified from the biopsy of the tissue overlying the largest abscess. Samples were submitted for mycobacterial culture and sensitivities. The organism was grown and identified as belonging to the Mycobacterium abscessus group. The bat was treated with marbofloxacin at 25 mg/kg q 24 h, and azithromycin 20 mg/kg q 24 h.
Cases #2 and #3 were identified in May 2011. They were also treated with marbofloxacin and azithromycin. Investigation to identify the source of the mycobacterium included mycobacterial cultures from all insect cultures and water sources. The same Mycobacteria abscessus group was cultured from a water hose interior. The water hose was used to provide drinking and cleaning water for the group. The water hoses were removed from the husbandry routine. Bats were treated 4–6 months past any occurrence of disease.
Case #1 died February 2012. The bat had been treated for 13 months. He was the most severely affected and had continued reoccurrence of abscesses with multiple subcutaneous calcified nodules. This bat also had multicentric lymphoma. Cases #2 and #3 completed courses of treatment and appear to be recovered, without recurrence of lesions. A fourth case was identified in February 2012. This bat had one isolated abscess. The abscess was drained, and the bat started on a similar treatment protocol.