OBJECTIVETo scan the most resistable bacteriophage as an indicator in disinfection tests, and to study the resistance of bacteriophage T4, Phichi 174D, and f2 to the sodium dichloroisocyanurate (NaDCC) in laboratory.

METHODSThe virucidal activity of NaDCC against bacteriophage T4, Phichi 174D, and f2 were assessed by suspension test. The neutralizer was selected and be appraised by test of neutralizer. Bacteriophage T4, Phichi 174D, and f2 were detected and enumerated by the double-agar-layer plaque technique.

RESULTS(1) With 150 mg/L of available chlorine of NaDCC solution, within a contact time of 40 minutes, or 300 mg/L, 5 minutes, the reductions of bacteriophage T4 achieved the "disinfection" level [log(10) inactivation value or log(10) reduction value of bacteriophage T4 (log(10)No-log(10)Nt) > or = 4.00 log(10)]. (2) With 300 mg/L of available chlorine of NaDCC solution, within a contact time of 5 minutes, or 400 mg/L, 3 minutes, the reductions of bacteriophage Phichi 174D achieved the "disinfection" level. (3) With 2000 mg/L of available chlorine of NaDCC solution, within a contact time of 20 minutes, or 4000 mg/L, 5 minutes, the reductions of bacteriophage f2 might achieve the "disinfection" level.

CONCLUSIONThe order of resistance of the above three bacteriophages to NaDCC from greatest to smallest is as follows: bacteriophage f2 > bacteriophage T4 > bacteriophage Phichi 174D.

Bacteriophage T4 ; drug effects ; Bacteriophage phi X 174 ; drug effects ; Bacteriophages ; drug effects ; Disinfectants ; pharmacology ; Drug Resistance, Viral ; Sodium Hypochlorite ; pharmacology

OBJECTIVETo evaluate the protective performance of a positive pressure bio-protective clothing against viral aerosol.

METHODSThe suspension of indicating virus phage Phi-X174 was made for viral aerosol generating in a hermetic cabin. The diameter of viral aerosol particles were measured with a aerodynamics size analyzer. By adjusting the inner humidity of the cabin, the protective efficiency of the positive pressure bio-protective clothing against viral aerosol in high and low windshield conditions was determined with Andersen six-stage air sampler sampling and plage forming unit (PFU) counting, respectively.

RESULTSThe mass median diameter of Phage Phi-X174 aerosol particles was about 0.922 µm and the background concentration is beyond 2 × 10⁴ particles/m³. The protective efficiency of the clothing against phage Phi-X174 aerosol particles was above 99.9% under different test conditions with the range of viral aerosol concentration between 0 - 23 PFU/m³. Airflow (P = 0.84), environment humidity conditions (P = 0.33) and sampling time (P = 0.07) did not affect the protective efficiency statistically.

CONCLUSIONThe positive pressure bio-protective clothing provided a relatively high efficiency against phage Phi-X174 aerosol regardless of airflow rate, environment humidity and sampling time.

Aerosols ; Bacteriophage phi X 174 ; Bioterrorism ; prevention & control ; Equipment Design ; Humidity ; Occupational Exposure ; prevention & control ; Pressure ; Protective Clothing ; Time Factors ; Virus Diseases ; prevention & control

BACKGROUNDTo screen for the most resistant bacteriophage as indicator in disinfection tests, the resistance of bacteriophage phi chi 174D, T4 and f2 to iodophor were observed in laboratory.

METHODSThe virucidal activity of iodophor against bacteriophage phi chi 174D, T4, and f2 were assessed by suspension test. The neutralizer is selected and appraised by testing with neutralizer. Bacteriophage phi chi 174D, T4, and f2 were detected and enumerated by the double-agar-layer plaque technique.

RESULTS(1) With 500 mg/L of available iodine of iodophor solution, within a contact time of 40 min, or 750 mg/L, 10 min, or 1000 mg/L, 5 min, the reduction of bacteriophage phi chi 174D could achieve the "disinfection" level [log10 inactivation value (LIV) or log10 reduction value (LRV) of bacteriophage phi chi 174D (log10 No-log10 Nt) was > or = 4.00 log10]. (2) With 600 mg/L of available iodine of iodophor solution, within a contact time of 40 min, or 700 mg/L, 5 min, the reductions of bacteriophage T4 could achieve the "disinfection" level. (3) With 50 mg/L of available iodine of iodophor solution, within a contact time of 10 min, or 75 mg/L, 10 min, the reductions of bacteriophage f2 could achieve the "disinfection" level.

CONCLUSIONThe order of resistance of the above three bacteriophages to iodophor from greatest to smallest is as follows: bacteriophage phi chi 174D greater than bacteriophage T4 > bacteriophage f2.

Bacteriophage T4 ; drug effects ; Bacteriophage phi X 174 ; drug effects ; Bacteriophages ; drug effects ; Disinfectants ; pharmacology ; Disinfection ; methods ; Dose-Response Relationship, Drug ; Drug Resistance, Viral ; Iodophors ; pharmacology ; Surface-Active Agents ; pharmacology ; Virus Inactivation ; drug effects