Occurrence and fate of antibiotic resistant bacteria in sewage
Table 4.3. Average percentages (%) of antibiotic-resistant coliforms and acinetobacters
in raw sewage, treated sewage and digested sludge determined by counts on media
countaining antibiotics.
Antibiotica
Avedøre plant
Lynetten plant
coliforms
acinetobacters
coliforms
acinetobacters
Raw sewage
Treated Sewage
Digested Sludge
Raw sewage
Treated sewage
Digested sludge
Raw sewage
Treated sewage
Digested sludge
Raw sewage
Treated sewage
Digested sludge
Ampicillin
51.4
60.3
34.2b
47.2
27.0a
20.0b
47.7
50.5
38.5
18.2
22.3
12.2
Gentamicin
1.4
1.8
1.1c
3.9
7.2
5.5
3.3
3.1
1.7
3.4
5.8
3.8
Tetracycline
2.0
2.2
3.7
10.8
11.5
4.3
4.9
2.2
3.2
12.3
12.9
16.7
All antibiotics
0.1
-c
0.3
0.1
-c
0.3
0.2
0.3
0.3
0.3
0.3
0.1
a The percentage of resistant bacteria in treated sewage was
significantly lower than in raw sewage (P<0.05). b The percentage of resistant bacteria in digested sludge was significantly
lower than in raw sewage (P<0.05). c Multiple resistance to ampicillin, gentamicin and tetracycline was not
detected in treated sewage from Avedøre.