Antimicrobial Test AATCC Test Method 174-1998 Antimicrobial Activity Assessment of Carpets – Part I and Part II
Test Organisms
- Staphylococcus aureus ATCC No. 6538 Gram-positive organism
- Klebsiella pneumoniae ATCC No. 4352 Gram-negative organism
Preparation of Specimen
| Sample | Description | Comments |
| Treated | Carpet | |
| Not treated | Carpet | |
| Treated – 1 GSA wash | Carpet | Treatment type: plant |
| Not treated – 1 GSA wash | Carpet | 1 GSA wash = 2 washes with soap and 5 washes with water |
Results
AATCC 174 – Part I
Staphylococcus aureus, ATCC No. 6538
| Sample | Growth | Inhibition Zone | Evaluation of the antimicrobial effect |
| Treated, front | Nil | Width = 4mm | Good effect, pronounced inhibition zone |
| Treated, back | Nil | Width = 6mm | Good effect, pronounced inhibition zone |
| Not treated, front | Medium | Width = 0mm | Insufficient effect |
| Not treated, back | Medium | Width = 0mm | Insufficient effect |
| Treated – 1 GSA wash, front | Nil | Width = 4mm | Good effect, pronounced inhibition zone |
| Treated – 1 GSA wash, back | Nil | Width = 6mm | Good effect, pronounced inhibition zone |
| Not treated – 1 GSA wash, front | Medium | Width = 0mm | Insufficient effect |
| Not treated – 1 GSA wash, back | Medium | Width = 0mm | Insufficient effect |
Klebsiella pneumoniae, ATCC No. 4352
| Sample | Growth | Inhibition Zone | Evaluation of the antimicrobial effect |
| Treated, front | Nil | Width = 1mm | Good effect, pronounced inhibition zone |
| Treated, back | Nil | Width = 1mm | Good effect, pronounced inhibition zone |
| Not treated, front | Medium | Width = 0mm | Insufficient effect |
| Not treated, back | Medium | Width = 0mm | Insufficient effect |
| Treated – 1 GSA wash, front | Nil | Width = 2mm | Good effect, pronounced inhibition zone |
| Treated – 1 GSA wash, back | Nil | Width = 0mm | Good effect |
| Not treated – 1 GSA wash, front | Medium | Width = 0mm | Insufficient effect |
| Not treated – 1 GSA wash, back | Medium | Width = 0mm | Insufficient effect |
- The specimens were incubated at 37C for 24 hours.
- The width of the clear zone was calculated by the following equation: W = (T-D)/2 where W=width of clear zone of inhibition in mm, T=total width of test specimen and clear zone in mm, D=width of the test specimen in mm.
- The observation of inhibition:
| Growth | Evaluation of the antimicrobial effect |
| Nil | Good effect, pronounced inhibition zone |
| Nil | Good effect |
| Weak | Almost complete inhibition |
| Medium | Insufficient effect |
AATCC 174 – Part II
Staphylococcus aureus, ATCC No. 6538
| Sample Identification¹ | CFU/ml at “0” time contact | CFU/ml after “24 hrs” contact | Percent reduction R%² |
| Control sample | 2.5 x 10^5 | 3.4 x 10^7 | – |
| Treated | 1.5 x 10^5 | <100 | >99.9% |
| Not treated | 1.7 x 10^5 | 1.4 x 10^7 | NR |
| Treated – 1 GSA wash | 1.0 x 10^5 | <100 | >99.9% |
| Not treated – 1 GSA wash | 1.9 x 10^5 | 6.4 x 10^6 | NR |
Klebsiella pneumoniae, ATCC No. 4352
| Sample Identification¹ | CFU/ml at “0” time contact | CFU/ml after “24 hrs” contact | Percent reduction R%² |
| Control sample | 2.0 x 10^5 | 1.1 x 10^8 | – |
| Treated | 1.2 x 10^5 | 2.6 x 10^4 | 87.0% |
| Not treated | 1.8 x 10^5 | 9.5 x 10^7 | NR |
| Treated – 1 GSA wash | 1.5 x 10^5 | 2.4 x 10^4 | 88.0% |
| Not treated – 1 GSA wash | 1.6 x 1-^5 | 1.0 x 10^8 | NR |
Notes:
- 1 piece of swatches with 48mm diameter
- Percent reduction was calculated: R% = 100(B-A)/B % where A=the number of bacteria recovered from the samples after “24 hours” contact and B=the number of bacteria recovered from the samples at “0” time contact.
- NR = No reduction
- The control sample is an untreated cotton specimen (VA&G)