Comparison of microbial detection of hemodialysis water in reasoner’s 2a agar (R2a) and trypticase soy agar (tsa)

The quality management of dialysis water used as dialysis fluid is important for patients exposed to large amounts of water. The treatment of dialysis water causes chemical and microbiological contamination. Dialysis water contaminated with bacteria causes various diseases and inflammatory reactions due to the inflow of toxins into the body. Consequently, the aim of this study was to understand the sensitivity of agar for the detection of bacteria in dialysis water, the seasonal characteristics of bacterial culture, and bacterial identification. In all, 420 samples of dialysis water collected from a hospital between September 2017 and August 2018 were cultured at clinical laboratories. The bacterial growth rate of R2A was 99 cases (23.5%), and that of TSA was 47 cases (11.1%). R2A was more sensitive than TSA for samples incubated above 1 CFU/ml in hemodialysis, and TSA was more sensitive than R2A for samples incubated above 50 CFU/ml. The morphological characteristics of the microorganisms were confirmed by gram staining 188 strains of 30 isolates from the specimens. In R2A, Gram-positive bacteria were isolated in 33.3% (n = 42), Gram-negative bacteria were isolated in 56.3% (n = 71), and fungal strains were isolated in 10.3% (n = 13). In TSA, Gram-positive bacteria were isolated in 33.8% (n = 21), Gram-negative bacteria were isolated in 64.5% (n = 40), and fungal strains were isolated in 1.6% (n = 1). In addition, seasonal distinctions were observed in microbial cultures.