title: Recurrent bacteremia caused by the Acinetobacter calcoaceticus-Acinetobacter baumannii complex.
abstract: 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.
authors: Department of Intensive Care Medicine, Chi-Mei Medical Center, Liouying, Tainan, Taiwan.
authors: Chih-Cheng
authors: CC
authors: Lai
authors: Han-Lin
authors: HL
authors: Hsu
authors: Che-Kim
authors: CK
authors: Tan
authors: Hsih-Yeh
authors: HY
authors: Tsai
authors: Aristine
authors: A
authors: Cheng
authors: Chia-Ying
authors: CY
authors: Liu
authors: Yu-Tsung
authors: YT
authors: Huang
authors: Chun-Hsing
authors: CH
authors: Liao
authors: Wang-Huei
authors: WH
authors: Sheng
authors: Po-Ren
authors: PR
authors: Hsueh
mesh_terms: D000046:Academic Medical Centers; D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology* / Q000401:mortality; D040981:Acinetobacter baumannii / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D016954:Acinetobacter calcoaceticus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000453:epidemiology / Q000382:microbiology* / Q000401:mortality; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D058889:Molecular Typing; D019105:Random Amplified Polymorphic DNA Technique; D012008:Recurrence; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D013624:Taiwan / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents