Malke H
Mol Gen Genet. 1974;135(4):349-67. doi: 10.1007/BF00271149.
Of 5 clinically isolated strains of Streptococcus pyogenes, 3 showed high-level resistance to erythromycin and lincomycin that was inducible by subinhibitory concentrations of these drugs (IR strains) while 2 strains exhibited constitutive erythromycin and lincomycin resistance (CR strains) which was expressed without prior exposure to low drug concentrations. The CR strain 15346 showed spontaneous loss of resistance whereas resistance in the other strains was quite stable even under curing conditions. The IR strain 13234 was found to be polylysogenic for at least 4 different phages designated P13234ma, mi, mu, and mo. Phage mo, antigenically distinct from the other three, was shown to mediate the transfer of the resistance determinant ERL1 of strain 13234. ERL1 if borne by appropriate strains was also transducible by the virulent phage A25. ERL1 behaved as a discrete genetic unit in transduction experiments, was not linked to either of two chromosomal regions governing resistance to antibiotics that affect the ribosome, could be transferred to recombination deficient hosts, represented a relatively large UV inactivation target, and showed no stimulation of transduction by low UV doses. These findings suggest that resistance to erythromycin and lincomycin in certain natural isolates of S. pyogenes is specified by, or under the control of, a plasmid.
在5株临床分离的化脓性链球菌菌株中，3株对红霉素和林可霉素表现出高水平耐药性，这种耐药性可被这些药物的亚抑菌浓度诱导（诱导型耐药菌株），而2株表现出组成型红霉素和林可霉素耐药性（组成型耐药菌株），在未预先接触低药物浓度的情况下即可表达。组成型耐药菌株15346显示出耐药性的自发丧失，而其他菌株的耐药性即使在消除条件下也相当稳定。发现诱导型耐药菌株13234至少对4种不同的噬菌体具有多溶源性，这些噬菌体分别命名为P13234ma、mi、mu和mo。噬菌体mo在抗原性上与其他三种不同，已证明它介导了菌株13234的耐药决定簇ERL1的转移。如果由合适的菌株携带，ERL1也可被烈性噬菌体A25转导。在转导实验中，ERL1表现为一个离散的遗传单位，与控制对影响核糖体的抗生素耐药性的两个染色体区域均无连锁关系，可转移到重组缺陷宿主中，代表一个相对较大的紫外线灭活靶点，并且低剂量紫外线照射不会刺激转导。这些发现表明，化脓性链球菌某些自然分离株对红霉素和林可霉素的耐药性是由质粒决定或受其控制的。
