Nonautomated Blood Cultures in a Low-Resource Setting: Optimizing the Timing of Blind Subculture

AEROBIC BLOOD CULTURES AND COMPARISON TO CLINICAL FINDINGS OF FREE-RANGING GREEN TURTLES (CHELONIA MYDAS) IN EAST CENTRAL FLORIDA

Positive blood cultures have been identified in debilitated, stranded, and deceased green turtles (Chelonia mydas), suggestive of septicemia. Interpretation of these results is often difficult because multiple studies have previously identified bacteremia in clinically healthy reptiles. In this study, paired blood cultures and skin cultures obtained after aseptic preparation of the venipuncture site were collected from 50 immature free-ranging green turtles from Port Canaveral, Florida. Blood culture results were compared with health status (apparently healthy versus unhealthy, based on physical examination findings and appropriate body condition), date of collection, presence of external fibropapillomatosis, healed or unhealed injuries, and presence of barnacles. Weight, body condition score, body condition index, morphometric measures, volume of blood collected, and body temperature were compared between blood culture-positive and blood culture-negative turtles. Positive blood cultures were identified in 14% (7 of 50) of all turtles, including 15.6% (5 of 32) of apparently healthy turtles. Vibrio spp., Bacillus megaterium, Cellulomonas sp., and Staphylococcus pasteuri were isolated in blood culture from apparently healthy individuals. There was a significant association (P = 0.048) between positive skin cultures and positive blood cultures, but isolates obtained were consistently different between paired results. There was no significant association (P > 0.05) between blood culture results and health status, evidence of healed or unhealed injuries, external fibropapillomatosis, or presence of barnacles. Based on the results of this study, positive blood cultures suggestive of nonclinical bacteremia may be present in apparently healthy green turtles. The results of this study will aid the attending clinician in interpretation of blood culture results of apparently healthy or presumed septicemic captive and rehabilitating green turtles as part of the conservation and population recovery of this threatened species.

Comparative evaluation of Panther Fusion and real-time PCR for detection of Burkholderia pseudomallei in spiked human blood

Introduction. Melioidosis is an infection that most commonly presents with bacteraemia. Culture-based laboratory methods can result in a significant delay to organism identification. Molecular diagnostic techniques have a high sensitivity and rapid time to diagnosis. A decreased time to diagnosis is likely to improve patient outcomes.

Aim. To compare the Panther Fusion automated molecular instrument to an in-house method for the detection of Burkholderia pseudomallei directly from spiked human whole-blood samples.

Results. The in-house method detected 11/12 (92 %) samples with a B. pseudomallei concentration of 2.5–4.5×10² c.f.u. ml⁻¹. The Panther was less reliable, detecting only 8/14 (75 %) samples with a similar bacterial concentration. The Panther was able to detect 12/12 (100 %) spiked blood culture-positive samples.

Conclusion. The direct detection of B. pseudomallei from patient blood on presentation to a healthcare facility will significantly decrease time to diagnosis. We describe an in-house real-time PCR method with the lowest reported limit of detection to date. Due to lower sensitivity, the Panther Fusion would be best used as a diagnostic method directly from a positive blood culture.