Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying, Tainan, Taiwan.
J Clin Microbiol. 2012 Sep;50(9):2982-6. doi: 10.1128/JCM.01194-12. Epub 2012 Jul 3.
This study investigated the clinical and microbiological characteristics of patients with recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii (ACB) complex at a medical center. All ACB complex isolates associated with recurrent bacteremia were identified to the genomic species level using a 16S-23S rRNA gene intergenic spacer sequence-based method. Genotypes were determined by the random amplified polymorphic DNA patterns generated by arbitrarily primed PCR and by pulsotypes generated by pulsed-field gel electrophoresis. Relapse of infection was defined as when the genotype of the recurrent isolate was identical to that of the original infecting strain. Reinfection was defined as when the genospecies or genotype of the recurrent isolate differed from that of the original isolate. From 2006 to 2008, 446 patients had ACB complex bacteremia and 25 (5.6%) had recurrent bacteremia caused by the ACB complex. Among the 25 patients, 12 (48%) had relapse of bacteremia caused by A. nosocomialis (n = 7) or A. baumannii (n = 5). Among the 13 patients with reinfection, 5 (38.5%) had reinfection caused by different genospecies of the ACB complex. Most of the patients were immunocompromised, and most of the infection foci were catheter-related bloodstream infections. The overall in-hospital mortality rate was 33.3%. A. baumannii isolates had lower antimicrobial susceptibility rates than A. nosocomialis and A. pittii isolates. In conclusion, relapse of ACB complex bacteremia can develop in immunocompromised patients, especially those with central venous catheters. Molecular methods to identify the ACB complex to the genospecies level are essential for differentiating between reinfection and relapse of bacteremia caused by the ACB complex.
这项研究调查了一家医疗中心由鲍氏不动杆菌复合群（ACB）引起的复发性菌血症患者的临床和微生物学特征。所有与复发性菌血症相关的 ACB 复合群分离株均使用基于 16S-23S rRNA 基因间区序列的方法鉴定到种水平。通过随机扩增多态性 DNA 图谱和脉冲场凝胶电泳生成的脉冲型来确定基因型。感染复发定义为复发性分离株的基因型与原始感染株的基因型相同。再感染定义为复发性分离株的种或基因型与原始分离株不同。2006 年至 2008 年，446 例患者发生 ACB 复合菌血症，25 例（5.6%）发生由 ACB 复合菌引起的复发性菌血症。在 25 例患者中，12 例（48%）发生由 A. nosocomialis（n=7）或 A. baumannii（n=5）引起的菌血症复发。在 13 例再感染患者中，5 例（38.5%）由不同种的 ACB 复合群引起再感染。大多数患者免疫功能低下，感染灶大多为导管相关血流感染。总的院内死亡率为 33.3%。A. baumannii 分离株的抗菌药物敏感性率低于 A. nosocomialis 和 A. pittii 分离株。总之，免疫功能低下的患者，尤其是有中心静脉导管的患者，可能会发生 ACB 复合菌血症的复发。识别 ACB 复合群到种水平的分子方法对于区分由 ACB 复合群引起的菌血症再感染和复发至关重要。
