Background: S.aureus is the most common pathogen associated with injection drug use-associated endocarditis (IDUaIE). Our centre has a high incidence of IDUaIE and the opiate of choice in our population is hydromorphone controlled release (HCR), a prescribed oral opiate widely used in Canada and Europe. The complex technique for preparation for injection provides multiple opportunities for contamination of the solution and the controlled-release preparation contains several excipients (carbohydrates, protein, and iron), which could enhance Staphylococcal survival. A large amount of drug remains in the injection drug preparation equipment (IDPE) after each use and therefore, used IDPE is saved by people who inject drugs (PWID) for subsequent reuse by adding more water and then injecting the solution intravenously.
Methods: Used IDPE was collected from active PWID, rinsed with sterile water, aspirated into a syringe in a technique which mimicked reuse of equipment by PWID, and then plated on Mannitol salt agar (MSA). Bacterial isolates from local bacteremic PWID were used to test the survival of S. aureus (MRSA and MSSA) and S. pyogenes on unused IDPE with HCR or hydromorphone immediate release (HIR). The solutions were aspirated using techniques similar to that of local PWID and then plated on MSA and Blood agar.
Results: A total of 109 used IDPE samples were collected between March 2017 and March 2018. S. aureus was detected in 15/94 (16%) IDPE samples that had been used for injection of HMC (7 MRSA, 7 MSSA, and 2 borderline resistant [one sample contained both MRSA and MSSA]), but 0/15 (0%) samples used for hydromorphone immediate release (HIR). HCR, but not HM, was associated with greater survival of MSSA and MRSA (but not S. pyogenes) in solutions of the drug when compared to sterile water vehicle control (fig 1). There was a 2-log reduction in the number of viable S. aureus when IDPE containing HCR solutions spiked with MRSA or MSSA were heated with a cigarette lighter until bubbling (<10 sec).
Conclusion: IDPE that has been used in the preparation of HCR is frequently contaminated with S. aureus; and in vitro HCR, but not HM, prolongs the survival of MRSA and MSSA. Heating IDPE may be an effective harm-reduction strategy to reduce bacterial complications of injection of HCR.
D. Glockler-Lauf, None
L. Ball, None
B. Hallam, None
S. Koivu, None
J. McCormick, None
M. Silverman, None