An experiment on the growth of Serratia marcescens in formulated fluids for transfusion kept at room temperature
(IASR 2000; 21:167-167)
Regarding the Serratia outbreak investigation, which was summarized in the same issue of IASR, intra-venous formulated fluid (iv fluid) was suspected as a source of contamination. The field investigation found that iv fluid was carried to the ward by pharmacists and mixture of drugs in iv fluid and connection of the iv route were done by ward nurses during 4-6pm of the previous day. Prepared iv route was stored under room temperature for 10 hours or more until given.
In order to estimate growth of Serratia marcescens under the same conditions, following experiments were carried out using the isolate from the outbreak case.
Nine iv fluids were employed including injectable glucose (GC), total electrolyte fluid (KN), injectable amino acid (AL), total amino acid (AP), injectable fat emulsion (IL), dextrose fluid (DX), high calorie sugar and electrolyte fluid (TP), sugar-electrolyte-amino acid fluid (AF), and sugar-electrolyte fluid (PT). Certain amount (1-8 cfu/ml) of S.marcescens was put in the iv fluids, and the growth level was measured after 6 and 24 hours under room temperature.
In 24 hours S.marcescens grew to 105 times or more in IL, 104-105 times in DX, and 102-105 times in KN, AF, and GC, respectively.
We put S.marcescens on rubber cap of the iv fluids and penetrated there by needle. We confirmed that the bacteria entered into fluid.
These evidences indicate that iv fluid can be a massive source of the bacteria under such conditions, and it may cause the cluster of sepsis cases in the short period time.
Reported by: Miyoko Endoh, Rumi Okuno, Yukako Shimojima, Iwao Murata, Hiromasa Sekine, and Yataro Kokubo, Tokyo Metropolitan Research Laboratoy of Public Health.
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