Rivera A, Rebollo M, Sánchez F, Navarro F, Miró E, Mirelis B, Coll P
Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, and Unitat de Microbiologia, Departament de Genètica i Microbiologia, Universitat Autònoma de Barcelona, Barcelona, Spain.
Clin Microbiol Infect. 2005 Sep;11(9):759-61. doi: 10.1111/j.1469-0691.2005.01216.x.
Resistance mechanisms and clonal relationships were determined for six Streptococcus pyogenes isolates with low- or high-level ciprofloxacin resistance. Four isolates displayed reduced susceptibility to ciprofloxacin and levofloxacin and had alterations in ParC: Ser80-->Pro (isolate emm3.1); Ser79-->Ala (two isolates emm6.0); and a double substitution Ser79-->Phe and Ala121-->Val (isolate emm12.27). Two isolates (emm12.26) displayed high-level resistance to ciprofloxacin and levofloxacin, as well as to other quinolones. These isolates had the same double substitution in ParC as isolate emm12.27, and an additional substitution (Ser81-->Tyr) in GyrA. Resistance patterns, emm typing and sequencing of the quinolone resistance-determining regions defined two clusters containing three and two isolates, respectively.
对六株具有低水平或高水平环丙沙星耐药性的化脓性链球菌分离株进行了耐药机制和克隆关系的研究。四株分离株对环丙沙星和左氧氟沙星的敏感性降低，且ParC发生了改变：Ser80→Pro（分离株emm3.1）；Ser79→Ala（两株分离株emm6.0）；以及双重替换Ser79→Phe和Ala121→Val（分离株emm12.27）。两株分离株（emm12.26）对环丙沙星、左氧氟沙星以及其他喹诺酮类药物表现出高水平耐药。这些分离株在ParC中具有与分离株emm12.27相同的双重替换，并且在GyrA中还有一个额外的替换（Ser81→Tyr）。喹诺酮耐药决定区的耐药模式、emm分型和测序确定了两个簇，分别包含三株和两株分离株。
