Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2017

Background

Candida bloodstream infections are associated with high morbidity and mortality and their incidence has increased significantly over past two decades. The aggressive use of immunosuppressive, chemotherapeutic and broad-spectrum antibacterial agents along with prolonged central venous catheterisation and total parenteral nutrition are well known risk factors for candidaemia¹. As these are also common risk factors for bacteraemia, it is possible that candidaemias may go undetected in patients with bacteraemia.

Aim

Improve detection of candidaemia in bacteraemic patients.

Method

Phase 1: An additional sabouraud agar plate containing antibiotics (SAB plate) was included for all positive blood cultures when initial subculturing was done for a month from 27^th September 2014.

Phase 2: In addition to above procedure, a second subculture was done onto SAB plates after 48 - 72 hours of further incubation of positive bottles from 28^th October 2014 for another month.

Phase 3: As the inclusion of a SAB plate to all positive blood cultures did not yield any positive results in phases 1 and 2, selective sub culturing after 48-72 hours of further incubation was carried out for patients with risk factors for candidaemia from 1^st December 2014 for 2 weeks.

Phase 4: Based on first 3 phases, the study was continued for further 33 weeks from 9 March 2015 according to phase 3 protocol.

Results

During phases 1 and 2, 395 positive bottles had additional SAB plates at  initial subculture and during phase 2, 217 out of 395 had an additional SAB plate after further incubation for 48-72 hours.  None of the subcultures were positive during both phases.

During phase 3, one grew Candida parapsilosis out of 57  subcultures.

During phase 4, one grew Candida albicans and another grew Candida parapsilosis out of 212 subcultures.

Conclusions

Subculturing positive blood culture bottles  from patients with risk factors for candidaemia onto SAB plates after further incubation for 48-72 hours could detect candidaemias that may go undetected due to co-existing bacteraemia.