[Comparative study on the resistance of phage and bacteria indicative of the disinfection effect on object surfaces].

Objective

To investigate the differences in resistance to chemical disinfectants between bacteriophage Phi-X174 and disinfection effect indicator microorganisms, Staphylococcus aureus and Escherichia coli.

Methods

Three commonly used disinfectants, including chlorine-containing disinfectants, alcohol-based disinfectants and quaternary ammonium salt disinfectants, were selected to analyze the differences in resistance of phage Phi-X174, Staphylococcus aureus and Escherichia coli by using the quantitative sterilization test of suspension.

Results

The 250 mg/L sodium dichloroisocyanurate solution treated for 10 minutes yielded log reduction values of 3.39, 7.25 and 7.37 against phage Phi-X174, Staphylococcus aureus and Escherichia coli respectively. The 40% ethanol for 1 minute yielded log reduction values of 0.03, 2.46 and 7.30 against phage Phi-X174, Staphylococcus aureus and Escherichia coli, respectively. The 100 mg/L benzalkonium chloride for 10 minutes yielded log reduction values of 1.41, 6.84 and 0.93 for phage Phi-X174, Staphylococcus aureus and Escherichia coli, respectively.

Conclusion

Phage Phi-X174 has stronger resistance to chlorine-containing disinfectants and alcohol-based disinfectants than Escherichia coli and Staphylococcus aureus. Its resistance to quaternary ammonium salt disinfectants is between that of Staphylococcus aureus and Escherichia coli.