Table 2 Dimensional distribution of the S. epidermidis aerosol expressed as mean of the total plate counts of the two positive controls.

From: Staphylococcus epidermidis is a safer surrogate of Staphylococcus aureus in testing bacterial filtration efficiency of face masks

Stage

50% effective cut-off diameter (µm)

IPC (CFU)

FPC (CFU)

1

7.0

179 ± 87

195 ± 32

2

4.7

206 ± 75

225 ± 60

3*

3.3

638* ± 237

789* ± 202

4*

2.1

518* ± 204

579* ± 144

5*

1.1

702* ± 318

958* ± 99

6*

0.65

9* ± 5

13* ± 6

Total CFU

2.25 × 103 ± 900

2.76 × 103 ± 500

MPS (µm)

2.75 ± 0.20

2.70 ± 0.1

  1. Initial positive control (IPC) and final positive control (FPC) values are listed together with total CFU and MPS.
  2. *From 3rd to 6th impactor stages, CFUs have been enumerated by means of the “positive hole” correction.
Back to article page