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.

Clinical and microbiologic characteristics of adult patients with recurrent bacteraemia caused by extended-spectrum β-lactamase-producing Escherichia coli or Klebsiella pneumoniae

“…In this study, we observed a substantial rate (16.7%) of recurrent bacteraemia due to ESBL-producing bacteria. This finding is similar to that reported for non-typhoid Salmonella bacteraemia (15.7%) [8] but differs from those observed in bacteraemia due to Staphylococcus aureus (20.3%) [9], E. coli (6.3%) [10], Acinetobacter baumannii (5.6%) [11] and Streptococcus pneumoniae (2.3%) [12]. Through PFGE analysis, we further found that 67.8% of the cases were caused by identical strains.…”

“…A previous study has reported a substantial rate (12%) of recurrent bacteraemia, and several independent predictors have been identified, including healthcare-associated origins, polymicrobial Gram-positive or fungal aetiology, inappropriate empirical antimicrobial therapy, related infection foci within the abdomen or endocardium and the use of intravenous catheters [7]. Other studies have demonstrated that recurrent bacteraemia occurs at a rate of 2.3% to 20.3% for a variety of specific pathogens [8][9][10][11][12]. However, the incidence and risk factors associated with recurrent bacteraemia by ESBL-EC or ESBL-KP have not yet been clarified.…”

Acinetobacter calcoaceticus–Acinetobacter baumannii Complex Is Not Equal to A. baumannii

“…2 As Acinetobacter calcoaceticus, Acinetobacter baumannii, Acinetobacter genomic species 3, and Acinetobacter genomic species 13TU are very closely related, it has been proposed to refer to these species as the A. calcoaceticus-A. baumannii complex (ACB complex).…”

“…Since the clinically relevant members of the ACB complex cannot be separated by currently available commercial identification systems, such as the Vitek 2, Phoenix, and Microscan systems, A. baumannii isolates in our study represent the ACB complex. 2 Species identification with commercial identification systems that are currently used in clinical microbiology laboratories remains problematic, and molecular methods have been developed and validated for identification of Acinetobacter species. 3 Given that A. baumannii, Acinetobacter genomic species 3, and Acinetobacter genomic species 13TU share important clinical and epidemiological characteristics, the need for species identification of the ACB complex in clinical microbiology laboratories is questionable.…”

“…baumannii complex (ACB complex), which also includes genospecies A. calcoaceticus, A. nosocomialis, and A. pittii. 2 As they are phenotypically similar and difficult to distinguish using routine laboratory methods, they have been proposed as a group. After the introduction of molecular methods to accurately identify each genospecies, the clinical characteristics of each have been clarified, and it has been better realized that every genospecies has its own distinct features.…”