Osteomyelitis in cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) hospitalized for rehabilitation: 25 cases (2008-2018)

Antimicrobial Pharmacokinetic Studies in Sea Turtles: A Review

Sea turtles face various threats to survival, primarily due to human activities, such as bycatch, vessel strikes, pollution, and climate change. Many of these activities can lead to illness or injuries, increasing the risk of infection. Treating infections appropriately and effectively requires knowledge of antimicrobial properties and their ability to eradicate microbes without harm to the sea turtle. Robust pharmacokinetic studies, therefore, are important for appropriate dosing. Herein, we review the studies detailing the pharmacokinetic properties of antimicrobials in sea turtles conducted to date.

Bone infection evolution

The present minireview aims to provide a context for imagination of the timespan for bone infection evolution from the origin of cellular bone tissue to modern orthopedic surgery. From a phylogenetic osteomyelitis-bracketing perspective, and due to the time of osteocyte origin, bacteria might have been able to infect the skeleton for approximately 400 million years. Thereby, bone infections happened simultaneously with central expansions of the immune system and development of terrestrial bone structure. This co-evolution might aid in explaining the many immune evasion strategies seen in the field of bone infections. Bone infection patients with long disease-free periods followed by sudden recurrence and anamnesis of long-term and low-grade infections indicate that bacteria can perform silent parasitism within bone tissue (parasitism; one organism lives on another organism, the host, causing it harm and is structurally adapted to it). The silence seems to be disturbed by immunosuppression and the present minireview shows that a compromised immune system has been associated with bone infection development across all species in the phylogenetic tree. Orthopedic surgery, including arthroplasty and osteosynthesis, favor introduction of bacteria and prosthesis/implant related infections are thus anthropogenic infections (anthropogenic; resulting from the influence of human beings on nature). In that light it is important to remember that the skeleton and immune system have not evolved for millions of years to protect titanium alloys and other metals, commonly used for orthopedic devices from bacterial invasion. Therefore, these relatively new orthopedic infection types must be seen as distinct with unique implant/prosthesis related pathophysiology and immunology.

Synovial fluid analysis in healthy green turtles Chelonia mydas in Taiwan

Septic arthritis is a frustrating disease in sea turtle rehabilitation because of its unclear pathogenesis, delayed onset during rehabilitation, long-term treatment requirements, and potentially poor prognosis. Radiography, blood cultures, and arthrocentesis have been used as diagnostic tools for suspected cases. However, there is currently a lack of data on the characteristics of synovial fluid in healthy sea turtles. To establish reference data for synovial fluid in sea turtles, we enrolled 14 green turtles Chelonia mydas rescued between 2019 and 2022 from 3 facilities using the following inclusion criteria: normal attitude and appetite, normal motor functions of the 4 limbs, no joint swelling, and no ongoing use of antibiotics for at least 1 mo. Bacterial cultures of blood and synovial fluid from the shoulder joints of these turtles were obtained and a qualitative analysis of the synovial fluid was performed. The results revealed bacterial culture-negative blood and synovial fluids at 37°C. Most characteristics of normal synovial fluid in green turtles, such as being transparent, colorless, and able to create a strand of over 2.5 cm by being pulled with a needle in viscosity trials, as well as the cytology of the normal synovial fluids being dominated by histiocytes and synovial lining cells, lymphocytes, and occasionally a few heterophils or erythrocytes were similar to those in mammals. This study provides information on the normal synovial fluid characteristics of green turtles in Taiwan, which may be beneficial for the diagnosis of joint diseases in sea turtles.

RETROSPECTIVE ANALYSIS OF BLOOD CULTURES AND THEIR ASSOCIATION WITH CLINICAL FINDINGS AND OUTCOME IN GREEN SEA TURTLES (CHELONIA MYDAS) AT A FLORIDA SEA TURTLE REHABILITATION FACILITY, 2017-2020

Septicemia is commonly suspected of sea turtles entering rehabilitation. However, blood culture results of green sea turtles (Chelonia mydas) are infrequently reported in the literature. Aerobic blood cultures were performed for intake examinations of 167 green sea turtles undergoing rehabilitation at Brevard Zoo's Sea Turtle Healing Center, Melbourne, Florida, USA from 2017 to 2020. The incidence of positive cultures during intake examinations was 24% (40/167). The most common bacterial isolates identified were Vibrio alginolyticus, Shewanella algae, Achromobacter xylosoxidans, Photobacterium damselae, Sphingomonas paucimobilis, and Vibrio parahaemolyticus. There was a statistically significant association (P < 0.05) between culture status and evidence of external injury. There was no significant association between culture status and Caryospora-like coccidia infection, or fibropapillomatosis. Culture-positive turtles had significantly lower (P < 0.05) total white blood cell, lymphocyte, monocyte, total protein, albumin, and calculated globulin values compared to turtles with negative blood cultures. Significantly more culture-positive turtles died in rehabilitation compared to culture-negative (P = 0.042). Positive blood cultures suggestive of septicemia are commonly found during intake examinations at a Florida sea turtle rehabilitation facility.

Steatitis in Cold-Stunned Kemp's Ridley Sea Turtles (Lepidochelys kempii)

The pathogenesis of steatitis that infrequently occurs in cold-stunned Kemp's ridley sea turtles (KRT; Lepidochelys kempii) has been undetermined. The objectives of this study were to investigate the clinical (n = 23) and histologic findings (n = 11) in cold-stunned KRT, and to compare plasma concentrations of α-tocopherol (vitamin E), thiobarbituric acid reactive substances (TBARS), and the TBARS to vitamin E (T/E) ratio (an assessment of oxidative stress) between cold-stunned KRT with clinically and/or histologically confirmed steatitis (n = 10) and free-ranging KRT (n = 9). None of the cold-stunned turtles had clinically detectable steatitis at admission, and the median number of days to diagnosis of steatitis was 71 (range 33-469). Histologic findings of affected adipose tissue included heterophilic (n = 9) and/or histiocytic (n = 5) steatitis, fat necrosis (n = 7), myonecrosis (n = 2), and intralesional bacteria (n = 6). Cold-stunned KRT had significantly lower plasma vitamin E concentrations (median = 3.5 nmol/g), lower plasma TBARS concentrations (median = 1.6 nmol/g), and higher T/E ratios (median = 0.37), than controls (208.8 nmol/g; 2.1 nmol/g; 0.01, respectively). These results suggest a multifactorial etiology for the development of steatitis in KRT during rehabilitation, including tissue injury, septicemia, and various factors resulting in imbalances of anti-/oxidative status. By highlighting the need to provide more effective vitamin E supplementation, and the need to re-assess specific components of the diet, this study may lead to reduced incidence and improved medical management of steatitis in cold-stunned sea turtles.