The turbidimetric stability of common clinical bacterial isolates in water

Ninety common clinical bacterial isolates were suspended in sterile deionized, tap and lake water to a turbidity of 100 Klett-Summerson Colorimeter Units. The suspensions were then measured for turbidity at seven and 14 days of storage at 25 degrees C. Turbidities for Proteus mirabilis, Klebsiella pneumoniae and Escherichia coli were stable for 14 days, however those of Serratia marcescens, Pseudomonas aeruginosa, Staphylococcus aureus and S. epidermidis were unstable as evidenced by a decreased turbidity. Staphylococci were much less stable in deionized water than tap or lake water. Overall, the turbidity of most isolates was most stable in lake followed by tap and deionized water, respectively.