Table 1.

Antibiotic resistance determinants identified and characterized in lactobacilli, bifidobacteria, and probiotic Bacillus strains.

Gene(s)	Resistance	Mechanism	Location	Reference
Lactobacillus
blaZ	β-Lactams	Antibiotic hydrolysis	–	Aquilanti et al. (2007)
vat(E)	Quinupristin–dalfopristin	Antibiotic acetylation	–	Mayrhofer et al. (2010)
Cat	Chloramphenicol	Antibiotic acetylation	Plasmid	Ahn et al. (1992); Lin et al. (1996); Hummel et al. (2007); Mayrhofer et al. (2010)
msrC	MLS	Efflux	–	Thumu and Halami (2012)
mef(A)	Macrolide	Efflux	–	Cauwerts et al. (2006)
aac(6′)-aph(2′′), ant(6), aph(3′)-IIIa	Aminoglycoside	Enzymatic modification	–	Rojo-Bezares et al. (2006)
erm(B), erm(C), erm(T), erm(LF), erm(GT), erm(A)	MLS	Ribosomal methylation	Plasmid, transposon, chromosome	Tannock et al. (1994); Gfeller et al. (2003), Cauwerts et al. (2006); Aquilanti et al. (2007), Hummel et al. (2007); Klare et al. (2007), Ammor et al. (2008b); Egervärn et al. (2009), Mayrhofer et al. (2010); Thumu and Halami (2012)
tet(W), tet(M), tet(S), tet(O), tet(Q), tet(36), tet(Z), tet(W/O), tet(O/W/32/O/W/O)	Tetracycline	Ribosomal protection	Plasmid, transposon, chromosome	Aquilanti et al. (2007); Klare et al. (2007), Ammor et al. (2008b), van Hoek et al. (2008b,c)
tet(K)/tet(L)	Tetracycline	Efflux	Plasmid	Aquilanti et al. (2007); Ammor et al. (2008c), Devirgiliis et al. (2009); Thumu and Halami (2012)
Bifidobacterium
erm(X)	MLS	Ribosomal methylation	Transposon	van Hoek et al. (2008a)
tet(W), tet(M), tet(O), tet(W/32/O), tet(O/W)	Tetracycline	Ribosomal protection	Chromosome	Flórez et al. (2006); Kazimierczak et al. (2006), Ammor et al. (2008a); van Hoek et al. (2008b)
tet(L)	Tetracycline	Efflux	Chromosome	van Hoek et al. (2008b)
Bacillus
aaD2	Aminoglycoside	Antibiotic adenylation	Chromosome	Bozdogan et al. (2003)
erm(34)	MLS	Ribosomal protection	Chromosome	Bozdogan et al. (2004)
BCL-1	β-lactams	Antibiotic hydrolysis	Chromosome	Girlich et al. (2007)
cat(Bcl)	Chloramphenicol	Antibiotic acetylation	Chromosome	Galopin et al. (2009)