基于全基因组测序的HMKP耐药基因和毒力因子分析

Analysis of antimicrobial resistance genes and virulence factors of hypermucoviscous Klebsiella pneumoniae based on whole-genome sequencing

    摘要
  • 摘要:
    目的 采用全基因组测序（WGS）技术分析重症医学科（ICU）分离的高黏性肺炎克雷伯菌（HMKP），以了解其病原学及基因组特征。
    方法 收集31株经鉴定及拉丝试验（≥5 mm）确证的HMKP，进行药敏试验；通过WGS分析菌株的多位点序列分型（MLST）、K血清型、耐药基因及毒力因子，并对高毒力株（hvKP）进行验证。
    结果 HMKP感染者平均年龄为（64.55±11.31）岁，标本主要源于血液（13份）及脓液（11份），临床以肝脓肿等侵袭性感染为主；3株为碳青霉烯类耐药（CR-HMKP），其余对多数抗菌药物敏感。WGS鉴定了17个ST型，以ST23（32.26%）为主，K血清型以K1（35.48%）和K2（29.03%）为主，MLST聚类分析显示hvKP具有高度同源性；耐药基因中SHV检出率最高（93.55%），碳青霉烯酶基因涉及KPC-18及OXA-232；除rmpA2（22.58%）外，其他毒力基因（如iutA、entB）检出率均＞80%。共鉴定出27株hvKP，WGS与PCR结果高度一致。
    结论 该院ICU分离的HMKP具有明显的侵袭性及高毒力特征，血清型以K1、K2为主，MLST以ST23为主，CR-HMKP的检出提示临床应警惕耐药与高毒力并存的风险，加强ICU感染监测与防治。

     

    Abstract:
    OBJECTIVE To analyze the hypermucoviscous Klebsiella pneumoniae （HMKP） isolated from the intensive care unit （ICU） through whole-genome sequencing （WGS） technology, thereby understanding its etiology and genomic characteristics.
    METHODS A total of 31 strains of HMKP confirmed by identification and the string test （≥5 mm） were collected for antimicrobial susceptibility testing. WGS was employed to analyze the multi-locus sequence typing （MLST）, K serotype, antimicrobial resistance genes and virulence factors of the strains. Hypervirulent K. pneumoniae （hvKP） were verified.
    RESULTS The average age of patients infected with HMKP was （64.55 ± 11.31） years, and the specimens mainly originated from blood （n=13） and pus （n=11）. Invasive infections, such as liver abscesses, were the main clinical manifestations. Three strains were carbapenem-resistant HMKP （CR-HMKP）, and the rest were sensitive to most antimicrobial agents. WGS identified 17 STs, predominantly ST23 （32.26%）, with K1 （35.48%） and K2 （29.03%） being the main K serotypes. MLST cluster analysis showed that hvKP had high homology.Among the resistance genes, SHV had the highest detection rate （93.55%）, and carbapenemase genes involved KPC-18 and OXA-232. Except for rmpA2 （22.58%）, the detection rates of other virulence genes （such as iutA, entB） were all ＞80%. A total of 27 hvKP strains were identified, and the results of WGS and PCR were highly consistent.
    CONCLUSIONS The HMKP strains isolated from the ICU exhibited marked invasive and hypervirulent traits, with K1/K2 as the predominant serotypes and ST23 as the predominant sequence type. The emergence of CR-HMKP signals the convergence of resistance and high virulence, urging enhanced infection surveillance and control in the ICU.

     

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