Table 1.

PCR primers used in this study^a

Primer name	Organism(s) used	Specificity	Orientation	Sequence (5′–3′)
Ec8	E. coli	Conserved general	Forward	AGAGTTTGATCATGGCTCAGATTG
Ec1507	E. coli	Conserved general	Reverse	TACCTTGTTACGACTTCACCCCAG
Bpsf	Betaproteobacteria	Selective	Forward	CACATGCAAGTCGTACGGCAGCAC
Gpsf	Gammaproteobacteria	Selective	Forward	CAGRCCTAACACATGCAAGTCGAG
BGpsr	Beta- and gammaproteobacteria	Selective	Reverse	TTGTTACGACTTCACCCCAGTCAT
BGDf	Beta- and gammaproteobacteria	Conserved sequencing	Forward	CGTGCCAGCAGCCGCGGTAATACG
BGDr	Beta- and gammaproteobacteria	Conserved sequencing	Reverse	CGTATTACCGCGGCTGCTGGCACG
BGMf	Beta- and gammaproteobacteria	Conserved sequencing	Forward	ACAGGTGCTGCATGGCTGTCGTCA
BGMr	Beta- and gammaproteobacteria	Conserved sequencing	Reverse	TGACGACAGCCATGCAGCACCTGT

^aAll primers were designed against bacterial 16S rRNA genes.