TABLE 2.

Frequencies of isolation of CBA-degrading isolates and the genotype distribution by carbon source

Carbon sourcea	No. of isolates at enrichment temp (°C):				No. of isolates carrying the three genotypesb (%)
	32	22	4	Total	cbaABC	clcABD	fcbB
3-CBA	54	51	22	127	3 (2.4)	9 (7.1)
4-CBA	91	75	48	214	0 (0)	3 (1.4)	4 (1.9)
3,4-DCBA	15	10	6	31	2 (6.5)	0 (0)
3-CBA (3-CBP)	45	31	16	92	4 (4.3)	3 (3.3)
Total	205	167	92	464	9 (1.9)	15 (3.2)	4 (0.9)

^aAbbreviations are as noted for Table 1, with the addition of 3-CBA (3-CBP), isolates from 3-CBA plates of samples previously enriched on 3-CBP. 

^bGenotypes are as described for Table 1. The numbers in parentheses are the percentages of isolates of each genotype relative to the total number of isolates for that carbon source, as listed in column 4. The fcbB genotype was only screened for among the 4-CBA isolates. ERIC PCR revealed four sets of two sibling species among the 15 clcABD isolates (see Materials and Methods). Each sibling was isolated independently from different sites and different sampling times; therefore, they are included in the total for that genotype. No sibling species were found among the cbaABC and fcbB isolates.