不同荚膜血清型ST11-CRKP菌株耐药和基因组特征分析

Analysis of drug resistance and genomic characteristics of ST11-CRKP strains with different capsular serotypes

    摘要
  • 摘要:
    目的 分析不同荚膜血清型的ST11-CRKP耐药性和基因组学特征。
    方法 2024年6-12月从上海地区多家医院收集97株CRKP非重复菌株, 采用微量肉汤稀释法进行药敏试验, 通过二代测序及Kleborate等工具解析耐药基因、毒力位点及质粒特征。
    结果 ST11-CRKP占比最高(62.89%, 61/97), 对阿米卡星和氯霉素的耐药率高于非ST11型, 而对多黏菌素E的耐药率较低(P＜0.05)。ST11-CRKP以KL25(62.30%, 38/61)和KL64(27.87%, 17/61)血清型为主, KL25型中β-内酰胺类(CTX-M-65、TEM-1)、氨基糖苷类rmtB、氯霉素类catII、甲氧苄啶类dfrA14耐药基因的携带率高于KL64型, 但β-内酰胺类(SHV-182、SHV-134)、氨基糖苷类aadA2、喹诺酮类(LAP-2、QnrS1)耐药基因的携带率低于KL64型(P＜0.05)。88.52%(54/61)的菌株携带碳青霉烯类耐药质粒, 其中11.11%(6/54)为接合型; 93.44%(57/61)的菌株携带不可移动型毒力质粒。毒力质粒包括IncF、IncH和IncR, 碳青霉烯类耐药质粒包括IncF、IncR、IncU和ColRNAI。ST11-KL105型毒力低但均携带NDM类接合型质粒; ST11-KL47型无碳青霉烯耐药基因但携带毒力质粒; ST11-KL64/KL25型为高毒力碳青霉烯类耐药菌株, 且23.53%(4/17)的KL64型携带接合型碳青霉烯类耐药质粒。
    结论 ST11-CRKP以KL25和KL64荚膜血清型为主, ST11-KL105低毒力但携带NDM接合型耐药质粒, ST11-KL47低耐药性但携带毒力质粒, ST11-KL25和和KL64为高毒力碳青霉烯类耐药菌株, 且KL64型携带接合型耐药质粒, 存在较强的克隆传播风险, 需重点监测。

     

    Abstract:
    OBJECTIVE To analyze the drug resistance and genomic characteristics of ST11-CRKP strains with different capsular serotypes.
    METHODS From Jun. to Dec. 2024, 97 non-duplicated CRKP strains were collected from multiple hospitals in Shanghai. Microdilution broth method was used for antimicrobial susceptibility testing, and next-generation sequencing and tools like Kleborate were employed to analyze resistance genes, virulence loci and plasmid characteristics.
    RESULTS ST11-CRKP accounted for the highest proportion (62.89%, 61/97), with higher resistance rates to amikacin and chloramphenicol than non-ST11 strains, but a lower resistance rate to polymyxin E (P < 0.05). ST11-CRKP was predominantly serotype KL25 (62.30%, 38/61) and KL64 (27.87%, 17/61). Among KL25 strains, the carriage rates of β-lactams (CTX-M-65, TEM-1), aminoglycosides rmtB, chloramphenicol catII and trimethoprim dfrA14 resistance genes were higher than those in KL64 strains, but the carriage rates of β-lactams (SHV-182, SHV-134), aminoglycosides aadA2 and quinolones (LAP-2, QnrS1) resistance genes were lower than those in KL64 strains (P＜0.05). Totally 88.52% (54/61) of the strains carried carbapenem-resistant plasmids, of which 11.11% (6/54) were conjugative. 93.44% (57/61) of the strains carried non-mobilizable virulence plasmids. Virulence plasmids included IncF, IncH and IncR, and carbapenem-resistant plasmids included IncF, IncR, IncU and ColRNAI. ST11-KL105 strains had low virulence but all carried NDM conjugative plasmids, while ST11-KL47 strains did not carry carbapenem resistance genes but carried virulence plasmids. ST11-KL64/KL25 were highly virulent carbapenem-resistant strains, and 23.53% (4/17) of KL64 strains carried conjugative carbapenem-resistant plasmids.
    CONCLUSION ST11-CRKP are predominantly of KL25 and KL64 capsular serotypes. ST11-KL105 is low-virulent but carries an NDM conjugative resistance plasmid, ST11-KL47 is low-resistant but carries a virulence plasmid, and ST11-KL25 and KL64 are highly virulent carbapenem-resistant strains, with KL64 strains carrying conjugative resistance plasmids, posing a strong risk of clonal transmission and requiring special monitoring.

     

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