Division of Infectious Diseases, Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan.
Division of Infectious Diseases, Department of Public Health, Kobe University Graduate School of Health Sciences, 7-10-2 Tomogaoka Suma-ku, Kobe, 654-0142, Japan; Division of Urology, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, 650-0017, Japan.
J Microbiol Immunol Infect. 2023 Feb;56(1):93-103. doi: 10.1016/j.jmii.2022.08.010. Epub 2022 Aug 20.
Hypermucoviscous (HMV) Klebsiella pneumoniae produces large amounts of capsular polysaccharides, leading to high mortality. Since extended spectrum beta-lactamase (ESBL)-producing HMV K. pneumoniae strains have increased in Japan, we investigated and compared the antimicrobial susceptibilities and genetic characteristics of HMV and non-HMV ESBL-producing K. pneumoniae.
We investigated 291 ESBL-producing K. pneumoniae collected between 2012 and 2018, and in them 54 HMV strains were identified and comparable 53 non-HMV strains were selected. Then, ESBL gene detection, plasmid replicon typing, and virulence gene detection were done by PCR amplification.
Almost all of the HMV K. pneumoniae strains possessed uge (98.1%), wabG (96.3%), rmpA (94.4%), iucA (79.6%), fimH (70.4%), iroB (70.4%), and peg-344 (70.4%). These genes were found less frequently in non-HMV strains (uge 20.8%, wabG 83.0%, rmpA 7.5%, iucA 3.8%, fimH 9.4%, iroB 5.7%, and peg-344 1.9%). K2 capsule type (40.7%) was most common in HMV strains. HMV strains showed higher resistance to cefepime (p = 0.001) and piperacillin/tazobactam (p = 0.005) than non-HMV strains. CTX-M-15 (75.9%, 60.4%) was the dominant ESBL type in both HMV and non-HMV strains, and the most common plasmid replicon type was IncFII (52.1%) in CTX-M-15-producing strains.
We found that HMV strains had more virulence genes and showed higher resistance to antibiotics than non-HMV strains. The most common capsule type was K2. CTX-M-15 was the most common type of ESBL gene in both HMV and non-HMV strains in Japan. The FII plasmid might be related to the spread of CTX-M-15 among K. pneumoniae strains.
高黏液型（HMV）肺炎克雷伯菌产生大量荚膜多糖，导致高死亡率。由于产超广谱β-内酰胺酶（ESBL）的 HMV 肺炎克雷伯菌在日本的数量不断增加，我们对 HMV 和非 HMV ESBL 产肺炎克雷伯菌的抗菌药物敏感性和遗传特征进行了调查和比较。
我们调查了 2012 年至 2018 年间收集的 291 株产 ESBL 的肺炎克雷伯菌，其中鉴定出 54 株 HMV 菌株，并选择了 53 株可比的非 HMV 菌株。然后，通过 PCR 扩增检测 ESBL 基因、质粒复制子分型和毒力基因。
几乎所有 HMV 肺炎克雷伯菌菌株均携带 uge（98.1%）、wabG（96.3%）、rmpA（94.4%）、iucA（79.6%）、fimH（70.4%）、iroB（70.4%）和 peg-344（70.4%）。这些基因在非 HMV 菌株中发现的频率较低（uge 20.8%、wabG 83.0%、rmpA 7.5%、iucA 3.8%、fimH 9.4%、iroB 5.7%和 peg-344 1.9%）。K2 荚膜型（40.7%）在 HMV 菌株中最为常见。HMV 菌株对头孢吡肟（p=0.001）和哌拉西林/他唑巴坦（p=0.005）的耐药性高于非 HMV 菌株。CTX-M-15（75.9%，60.4%）是 HMV 和非 HMV 菌株中主要的 ESBL 类型，CTX-M-15 产生菌中最常见的质粒复制子类型是 IncFII（52.1%）。
我们发现 HMV 菌株具有更多的毒力基因，对抗生素的耐药性高于非 HMV 菌株。最常见的荚膜型是 K2。CTX-M-15 是日本 HMV 和非 HMV 菌株中最常见的 ESBL 基因类型。FII 质粒可能与 CTX-M-15 在肺炎克雷伯菌菌株中的传播有关。
