Inactivation of Burkholderia mallei in Equine Serum for Laboratory Use.

1 2 Lorraine Perrett and Ian Mawhinney 3 Animal and Plant Health Agency (UK) 4 5 6 The bacterium Burkholderia mallei is the cause of glanders. In the UK the disease was 7 eradicated from horses and other equids in 1928 and is now rarely reported 8 throughout the world. Freedom from disease is maintained in part by serological 9 screening prior to international travel. Serological testing is usually by the 10 complement fixation test (CFT) as defined in the OIE Manual of Diagnostic Tests and 11 Vaccines for Terrestrial Animals (1). 12 Samples are usually submitted to laboratories as whole blood. Prior to CFT the serum 13 is decanted and heat treated at 56-58°C for 30 minutes to inactivate the complement 14 in the sera to avoid non-specific reactions in the CFT. 15 Detection of bacteraemia in glanders seems to be uncommon in even in clinical 16 cases. (2,3,4). However concern has been raised that positive serological reactions 17 indicate suspicion of B.mallei infection and hence the possibility of the organism 18 being present in the serum which should be regarded as a potential risk to 19 laboratory workers. 20 The purpose of this study was to identify if the serum inactivation procedure for CF 21 testing also inactivates any potential B.mallei organisms in the blood sample. 22 Five to seven ml venous blood samples were taken from each of 2 healthy horses 23 into plain vacutainers. Initially we examined the viability of the spiking method to 24 produce ‘infected’ blood. From both samples 250μl were cultured onto Columbian 25 blood (CBA) and nutrient agar and incubated for 24 hours at 37°C prior to being 26 inoculated with B.mallei. (1 OIE). These blood samples were then seeded with 5027 JCM Accepted Manuscript Posted Online 11 February 2015 J. Clin. Microbiol. doi:10.1128/JCM.03141-14 Copyright © 2015, American Society for Microbiology. All Rights Reserved.