Ito Ryota, Shindo Yuichiro, Kobayashi Daisuke, Ando Masahiko, Jin Wanchun, Wachino Jun-ichi, Yamada Keiko, Kimura Kouji, Yagi Tetsuya, Hasegawa Yoshinori, Arakawa Yoshichika
Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, Nagoya, Japan Institute for Advanced Research, Nagoya University, Nagoya, Japan.
J Clin Microbiol. 2015 Mar;53(3):879-86. doi: 10.1128/JCM.03067-14. Epub 2015 Jan 7.
Some important virulence factors have been elucidated in Klebsiella pneumoniae infections. We investigated the relationship between virulence factors and multilocus sequence types (STs) and assessed the risk factors for bacteremia in patients with pneumonia due to K. pneumoniae. From April 2004 through April 2012, a total of 120 K. pneumoniae isolates from patients with pneumonia (23 with bacteremia and 97 without bacteremia) were collected from 10 medical institutions in Japan. Additionally, 10 strains of K. pneumoniae serotype K2 that were isolated >30 years ago were included in this study. These isolates were characterized using multilocus sequence typing (MLST), and the characteristics of their virulence factors, such as hypermucoviscosity phenotype and RmpA and aerobactin production between patients with and without bacteremia, were examined. MLST analysis was performed on the 120 isolates from patients with pneumonia, and some sequence type groups were defined as genetic lineages (GLs). GL65 was more prevalent among patients with bacteremia (21.7%) than in those without bacteremia (7.2%). The majority of the strains with serotype K2 were classified into GL14 or GL65, and rmpA and the gene for aerobactin were present in all GL65-K2 strains but absent in all GL14-K2 strains. In a multivariate analysis, the independent risk factors for bacteremia included GL65 (adjusted odds ratio [AOR], 9.46; 95% confidence interval [CI], 1.81 to 49.31), as well as neoplastic disease (AOR, 9.94; 95% CI, 2.61 to 37.92), immunosuppression (AOR, 17.85; 95% CI, 1.49 to 214.17), and hypoalbuminemia (AOR, 4.76; 95% CI, 1.29 to 17.61). GL65 was more prevalent among patients with bacteremia and was associated with the virulence factors of K. pneumoniae.
肺炎克雷伯菌感染中的一些重要毒力因子已得到阐明。我们研究了毒力因子与多位点序列类型（STs）之间的关系，并评估了肺炎克雷伯菌所致肺炎患者发生菌血症的危险因素。2004年4月至2012年4月，从日本10家医疗机构收集了120株肺炎克雷伯菌分离株（其中23例伴有菌血症，97例不伴有菌血症）。此外，本研究纳入了30多年前分离的10株肺炎克雷伯菌K2血清型菌株。采用多位点序列分型（MLST）对这些分离株进行特征分析，并比较了伴有和不伴有菌血症患者的毒力因子特征，如高黏液性表型、RmpA及气杆菌素的产生情况。对120株肺炎患者的分离株进行了MLST分析，并将一些序列类型组定义为遗传谱系（GLs）。GL65在伴有菌血症的患者中更为常见（21.7%），而在不伴有菌血症的患者中则较少见（7.2%）。大多数K2血清型菌株被归类为GL14或GL65，所有GL65-K2菌株均存在rmpA和气杆菌素基因，而所有GL14-K2菌株均不存在。在多变量分析中，菌血症的独立危险因素包括GL65（校正比值比[AOR]为9.46；95%置信区间[CI]为1.81至49.31），以及肿瘤性疾病（AOR为9.94；95%CI为2.61至37.92）、免疫抑制（AOR为17.85；95%CI为1.49至214.17）和低白蛋白血症（AOR为4.76；95%CI为1.29至17.61）。GL65在菌血症患者中更为常见，且与肺炎克雷伯菌的毒力因子相关。
