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. 2014 Aug 11;9(8):e104577.
doi: 10.1371/journal.pone.0104577. eCollection 2014.

Antibiotic susceptibilities of bacteria isolated within the oral flora of Florida blacktip sharks: guidance for empiric antibiotic therapy

Nathan R Unger  1 , Erich Ritter  2 , Robert Borrego  3 , Jay Goodman  4 , Olayemi O Osiyemi  5
Affiliations

Antibiotic susceptibilities of bacteria isolated within the oral flora of Florida blacktip sharks: guidance for empiric antibiotic therapy

Nathan R Unger et al. PLoS One. .

Abstract

Sharks possess a variety of pathogenic bacteria in their oral cavity that may potentially be transferred into humans during a bite. The aim of the presented study focused on the identification of the bacteria present in the mouths of live blacktip sharks, Carcharhinus limbatus, and the extent that these bacteria possess multi-drug resistance. Swabs were taken from the oral cavity of nineteen live blacktip sharks, which were subsequently released. The average fork length was 146 cm (±11), suggesting the blacktip sharks were mature adults at least 8 years old. All swabs underwent standard microbiological work-up with identification of organisms and reporting of antibiotic susceptibilities using an automated microbiology system. The oral samples revealed an average of 2.72 (±1.4) bacterial isolates per shark. Gram-negative bacteria, making up 61% of all bacterial isolates, were significantly (p<0.001) more common than gram-positive bacteria (39%). The most common organisms were Vibrio spp. (28%), various coagulase-negative Staphylococcus spp. (16%), and Pasteurella spp. (12%). The overall resistance rate was 12% for all antibiotics tested with nearly 43% of bacteria resistant to at least one antibiotic. Multi-drug resistance was seen in 4% of bacteria. No association between shark gender or fork length with bacterial density or antibiotic resistance was observed. Antibiotics with the highest overall susceptibility rates included fluoroquinolones, 3rd generation cephalosporins and sulfamethoxazole/trimethoprim. Recommended empiric antimicrobial therapy for adult blacktip shark bites should encompass either a fluoroquinolone or combination of a 3rd generation cephalosporin plus doxycycline.

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Conflict of interest statement

Competing Interests: In the interest of being thorough and transparent, the authors have the following relationships: 1. Nathan R. Unger: Employee of Nova Southeastern University, College of Pharmacy, a not-for-profit, private institution; 2. Erich Ritter: Employee of the Shark Research Institute, and University of West Florida; Author of Shark-Human Interaction and operator of SharkSchool.com; 3. Robert Borrego: Employee of St. Mary’s Medical Center, a not-for-profit institution; 4. Jay Goodman: Employee of St. Mary’s Medical Center, a not-for-profit institution; 5. Olayemi O. Osiyemi: Owner and president of Triple O Medical Services and Triple O Research Institute, which are private, non-commercial medical practices. However, these relationships do not alter the authors’ adherence to PLOS ONE policies or sharing data and materials and do not influence the authors’ research, analysis, or interpretations in the paper.

Figures

Figure 1
Figure 1. Swabbing the oral cavity of a blacktip shark.
Figure 2
Figure 2. Correlation between the fork length (cm) with the mean number of resistant antibiotics per shark.
Figure 3
Figure 3. Level of antibiotic resistance in the oral flora of blacktip sharks.
Figure 4
Figure 4. Upper right jaw of blacktip shark.
See this image and copyright information in PMC

References

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