Characterization of lsa(D), a Novel Gene Responsible for Resistance to Lincosamides, Streptogramins A, and Pleuromutilins in Fish Pathogenic Lactococcus garvieae Serotype II
Characterization of lsa(D), a Novel Gene Responsible for Resistance to Lincosamides, Streptogramins A, and Pleuromutilins in Fish Pathogenic Lactococcus garvieae Serotype II
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鱼类致病性嘉氏乳球菌血清型 II 中负责林可酰胺类、链阳菌素 A 和截短侧耳素抗性的新基因 lsa(D) 的表征
DOI：
10.1089/mdr.2020.0218
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发表时间：
2021
影响因子：
2.6
通讯作者：
Atushi Fujiwara and Issei Nishiki
中科院分区：
文献类型：
--
作者：
Yin-Ze Shi;Terutoyo Yoshida;Atushi Fujiwara and Issei Nishiki
目的：已从日本的养殖鱼类中分离出鱼类致病性加维乳球菌 II 型。本研究旨在探讨林可霉素（LCM）耐药的分子机制。 garvieeserotype II 并评估林可酰胺-链图菌素 A-截短侧耳素 (LSAP) 抗性表型的分子基础。结果：我们在 LSAP 抗性菌株中鉴定了一个 novellsa(D) 编码的 497-aa ATP 结合盒 F (ABC-F) 蛋白。 Lsa(D) 和其他 Lsa 型 ABC-F 蛋白推导的氨基酸之间的氨基酸一致性为 41.25–54.73%。此外，比较分析显示，LSAP敏感菌株中的等位基因oflsa(D)在233个氨基酸位点（TGG → TAG；色氨酸→过早终止密码子[PTC]）存在单点突变。抗菌药物对lsa(D)互补菌株和lsa(D)破坏突变体的最低抑制浓度证实lsa(D)具有LSAP抗性表型。逆转录聚合酶链反应无法检测到 LSAP 敏感菌株中 lsa(D) 等位基因变体的非编码区。此外，在实验室诱导的回复突变体中，LCM敏感菌株中的PTC（TAG）被TGG、CAG或TAT取代。结论：novelsa（D）赋予了临床LCM抗性菌株LSAP的抗性表型。 garvieeserotype II 菌株。然而，在L中发现了含有PTC的lsa(D)基因的等位基因。 garvieaeserotype II，导致 LSAP 易感表型。
Aims:Fish pathogenicLactococcus garvieaeserotype II has been isolated from cultured fish species in Japan. This study aimed to investigate the molecular mechanisms of lincomycin (LCM)-resistantL. garvieaeserotype II and assess the molecular basis for lincosamides–streptogramins A–pleuromutilins (LSAP)-resistant phenotype.Results:We identified a novellsa(D)-encoded 497-aa ATP-binding cassette F (ABC-F) protein in the LSAP-resistant strains. Amino acid identities of 41.25–54.73% were obtained between the deduced amino acids from Lsa(D) and other Lsa-type ABC-F proteins. Furthermore, comparative analysis revealed that the allele oflsa(D) with single point mutation at 233 aa position (TGG → TAG; tryptophan→premature termination codon [PTC]) in LSAP-sensitive strains. The minimum inhibitory concentrations of antimicrobials against thelsa(D) complementary strain andlsa(D)-disrupted mutant confirmed thatlsa(D) conferred the LSAP-resistant phenotype. The reverse transcription–polymerase chain reaction could not detect the noncoding region oflsa(D) allelic variant in the LSAP-sensitive strains. Additionally, the PTC (TAG) in LCM-sensitive strains was replaced by TGG,CAG, or TATin the laboratory-induced revertant mutants.Conclusions:The novellsa(D) conferred the LSAP-resistant phenotype in clinically LCM-resistantL. garvieaeserotype II strains. However, the allele oflsa(D) gene containing the PTC was found inL. garvieaeserotype II, resulting in the LSAP-susceptible phenotype.