TABLE 2.
Dominant cultivable microcosm isolates and their susceptibilities to selected antimicrobial agents, before and after 6 months of TCS exposure
| Type of isolate | No. of strains
|
MIC (μg/ml) ofa:
|
||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| CE
|
CP
|
CT
|
DP
|
FA
|
V
|
PV
|
ER
|
TCS
|
CH
|
|||||||||||||
| Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | Before | After | |
| Aeromonads | 3 | 0 | 0.3-15.3 | NA | 0.3-60 | NA | 0.3 | NA | 0.3-60 | NA | 0.3-3.0 | NA | 0.3-13.0 | NA | 0.3-60 | NA | 0.3-6.5 | NA | 0.3-T | NA | 0.3-5.2 | NA |
| Pseudomonads | 3 | 3 | 4.1-R | R | 0.3-1.6 | 0.3 | 0.3-0.9 | 1.1-1.8 | R | R | 9.9-R | R | 3.3-R | R | R | R | 0.3-R | R | 0.3-T | T | 1.0-T | NA |
| Serratia spp. | 1 | 0 | 0.3-R | NA | 0.3 | NA | 0.3-13.0 | NA | 6.8-R | NA | R | NA | 3.3-3.5 | NA | R | NA | 5.6-R | NA | T | NA | 2.3-7.9 | NA |
| Stenotrophomonads | 4 | 1 | 4.2-R | NA | 0.3-R | NA | 0.3-R | NA | 0.3-R | NA | 0.3-R | NA | 3.5-R | NA | 2.3-R | NA | 2.9-R | NA | T | NA | 2.2-T | NA |
| Ralstonia spp. | 0 | 2 | NA | 0.3-R | NA | 0.3-R | NA | 0.3-R | NA | R | NA | R | NA | R | NA | 4.3-R | NA | 0.3-R | NA | 1.3-3.1 | NA | 1.3-3.6 |
| Alcaligenes clade | 3 | 7 | 1.7-R | 0.3-R | 0.3-R | 0.3-R | 0.3-R | 0.3-4.3 | 1.1-R | 0.3-R | 8.5-R | R | 0.3-R | 1.4-R | 12.0-R | 0.3-R | 3.9-R | 0.3-R | 0.3-T | 1.9-T | 1.2-T | 0.9-T |
| Bacilli | 4 | 2 | 1.0-R | 0.3-1.9 | 1.4-R | 0.3 | 0.3-R | 0.3 | 0.9-R | R | 0.8-R | 0.8-1.6 | 0.3-R | 0.3 | 0.3-R | 0.3-1.2 | 0.3-R | 0.3 | 0.8-T | 0.8-3.0 | 0.6-T | 0.6-6.0 |
| Afipia spp. | 1 | 1 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 0.3 | 2.2-2.5 | 2.2-2.5 | 1.9-2.2 | 1.9-2.2 | 0.3 | 0.3 |
| Chryseobacterium spp. | 3 | 1 | 3.8-R | 11.1 | 0.3-R | 0.3 | 2.1-5.8 | R | 0.8-R | R | 0.3-R | R | R | 3.3 | 2.6-R | R | 2.6-R | R | 0.3-T | 2.8 | T | T |
| Microbacterium spp. | 1 | 0 | 6.9 | NA | R | NA | 2.7 | NA | 5.1 | NA | 1.4 | NA | R | NA | 6.2 | NA | 2.7 | NA | 4.3 | NA | T | NA |
| α Proteobacteria | 1 | 0 | 6.3 | NA | R | NA | R | NA | 2.7 | NA | 5.7 | NA | 3.1 | NA | 5.71 | NA | 0.3 | NA | 0.3 | NA | 2.5 | NA |
a
Data show susceptibility ranges. T, tolerant (>2 mg/ml); R, resistant (>200 μg/ml); NA, not applicable. Bacterial groupings are based on the phylogenetic tree (Fig. 1). CE, cetrimide; CP, ciprofloxacin; CT, chlortetracycline; DP, chloro-3,5-dimethyl-phenol; A, fusidic acid; V, vancomycin; PV, penicillin V; ER, erythromycin; CH, chlorhexidine.