Abstract

Deep biopsies were collected from the Longissimus dorsi and pectoralis muscles of wild Weddell seals near McMurdo Station, Antarctica as part of a larger study of the effects of aging. In order to assess the risk of infection from this procedure and the efficacy of cefazolin as prophylactic antibiotic, sterile swabs were collected from each site before and after biopsy and placed in microbial transport media (Amies with or without charcoal). The skin at the biopsy sites was swabbed before handling, then hair shaved and the skin cleaned with a dilute povidone iodine solution and/or isopropyl alcohol. Sterile surgical gloves and instruments were used to obtain the biopsies and the deep extent of the biopsy needle tract swabbed upon completion of sample collection but prior to final flushing with cefazolin solution. Smears were prepared immediately and swabs refrigerated until they could be shipped to a veterinary microbiology laboratory where gram stain, aerobic and fungal cultures were performed. Swabs produced no growth in four of 10 pectoralis wounds and eight of 12 longissimus wounds. Skin swabs from two of six pectoral sites and three of six longissimus sites also produced no growth. Wet skin was more likely to produce bacterial growth but positive skin culture was not predictive of wound contamination. Culture reports from the wound swabs to date have identified one fungal organism (Metarhizium anisopliae) and a variety of aerobic bacteria including beta hemolytic streptococci, Arcanobacterium phocae, Psychrobacter phenylpyruvica, a Rhodococcus- like bacteria and multiple as yet unidentified Psychrobacter-like species. Skin swabs produced coagulase positive staphylococci, coagulase negative staphylococci, gram-negative rods (non fermenters), Arcanobacterium phocae, Psychrobacter phenylpyruvica and Psychrobacter-like species. The Psychrobacter-like species were the most commonly found bacteria and were found in one or more samples from each of the four sites but further characterization will be required to positively identify these isolates. Initial antimicrobial sensitivity testing indicated that the Arcanobacterium and beta hemolytic streptococci were susceptible to cefazolin but the Psychrobacter and Psychrobacter-like species are too slow growing to test by conventional methods.