Molecular epidemiology, antimicrobial susceptibilities and resistance mechanisms of Streptococcus pyogenes isolates resistant to erythromycin and tetracycline in Spain (1994–2006)

Table 2 Macrolide resistance genotypes of 295 isolates of erythromycin-resistant S. pyogenes , indicating the phenotypes and emm /T types detected

Macrolide resistance genotype	No. of isolates	Phenotype^a			*emm*/T types^a
Macrolide resistance genotype	(%)	cMLS_B	iMLS_B	M	*emm*/T types^a
erm(B)	14 (4.7)	14	-	-	emm6T6 (1^b), emm11T11 (5^b)
					emm28T28 (6^c), emm71TNT (1)
					emm78T11 (1)
erm(B)/erm(A)	1 (0.3)	1	-	-	emm12T12
erm(B)/ msr(D)	5 (1.7)	5	-	-	emm11T11 (1^b), emm28T28 (3)
erm(B)/ msr(D)	5 (1.7)	5	-	-	emm88T28 (1)
erm(B)/mef(A)	21 (7.1)	20	-	1	emm4T4 (1), emm28T28 (18)
erm(B)/mef(A)	21 (7.1)	20	-	1	emm28TNT(1), emm75T25 (1)
erm(B)/ msr(D)/mef(A)	33 (11.2)	8	-	25	emm1T1 (1), emm2T2 (1)
					emm4T4 (14), emm6T6 (2)
					emm11T11 (2^b), emm12T12 (4)
					emm28T28 (4), emm75T25 (4)
					emm84T25 (1)
erm(B)/ msr(D)/ erm(A)	2 (0.7)	2	-	-	emm11T11 (2^b)
erm(B)/ erm(A)/mef(A)	7 (2.4)	5	2	-	emm11T11 (1^b), emm28T28 (4)
erm(B)/ erm(A)/mef(A)	7 (2.4)	5	2	-	emm77T28 (1^b), emm83TNT (1^b)
erm(B)/ msr(D)/mef(A)/ erm(A)	27 (9.2)	2	1	24	emm1T1 (1), emm4T4 (3)
					emm11T11 (1), emm12T12 (3)
					emm75T25 (14),emm81TB3264(1)
					emm84T25 (4)
erm(A)/mef(A)	6 (2.0)	1	1	4	emm2T2 (3), emm28T28 (2)
erm(A)/mef(A)	6 (2.0)	1	1	4	emm77T28 (1^b)
erm(A)	2 (0.7)	-	2	-	emm3T3/13 (1), emm22T12 (1)
erm(A)/ msr(D)	3 (1.0)	-	2	1	emm22T12 (2), emm75T25 (1)
msr(D)	1 (0.3)	-	-	1	emm3T3 (1)
msr(D)/mef(A)	112 (38.0)	-	-	112	emm1T1 (6), emm4T4 (62),
					emm6T6 (26), emm12T12 (10)
					emm28T28 (1), emm75T25 (6)
					emm84T25 (1)
msr(D)/mef(A)/ erm(A)	58 (19.7)	-	-	58	emm1T1 (1), emm4T4 (36)
					emm12T12 (2), emm12TNT (1)
					emm44T5/27/44 (1), emm75T25 (17)
None gene	3 (1.0)	2	-	1	emm1T1 (1), emm28T28 (1)
None gene	3 (1.0)	2	-	1	emm28TNT (1)
Total	295 (100)	60	8	227

^aNo. of GAS isolates. ^bAll isolates were also resistant to tetracycline, showing co-resistance to both erythromycin and tetracycline. ^cOne isolate showed co-resistance to both erythromycin and tetracycline.

ISSN: 1471-2180