Application of a microsphere-based array for rapid identification of Acinetobacter spp. with distinct antimicrobial susceptibilities.
Acinetobacter spp. have emerged as important nosocomial and multidrug-resistant pathogens in the last decade. A. calcoaceticus, A. baumannii, Acinetobacter genospecies 3, and Acinetobacter genospecies 13TU are genetically closely related and are referred to as the A. calcoaceticus-A. baumannii complex (ACB complex). Distinct Acinetobacter spp. may be associated with differences in antimicrobial susceptibility, so it is important to identify Acinetobacter spp. at the species level. We developed a microsphere-based array that combines an allele-specific primer extension assay and microsphere hybridization for the identification of Acinetobacter spp. This assay can discriminate the 13 different Acinetobacter spp. in less than 8.5 h, and it has high specificity without causing cross-reactivity with 14 other common nosocomial bacterial species. The sensitivity of this assay was 100 A. baumannii cells per ml of blood, and it could discriminate multiple species in various mixture ratios. The developed assay could differentiate clinical Acinetobacter spp. isolates with a 90% identification rate. The antimicrobial susceptibility test showed that A. baumannii isolates were resistant to most antimicrobial agents other than imipenem, while the genospecies 3 and 13TU isolates were more susceptible to most antimicrobial agents, especially ciprofloxacin and ampicillin-sulbactam. These results supported the idea that this assay possibly could be applied to clinical samples and provide accurate species identification, which might be helpful for clinicians when they are treating infections caused by Acinetobacter spp.
Lin
Yu-Chi
YC
Research and Diagnostic Center, Centers for Disease Control, Taipei, Taiwan.
Sheng
Wang-Huei
WH
Chang
Shan-Chwen
SC
Wang
Jann-Tay
JT
Chen
Yee-Chun
YC
Wu
Ruei-Jiuan
RJ
Hsia
Ko-Chiang
KC
Li
Shu-Ying
SY
D000150:Acinetobacter / Q000145:classification* / Q000187:drug effects / Q000302:isolation & purification*; D000151:Acinetobacter Infections / Q000175:diagnosis* / Q000382:microbiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001431:Bacteriological Techniques; D003428:Cross Infection / Q000175:diagnosis / Q000382:microbiology; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D024881:Drug Resistance, Bacterial; D006801:Humans; D008826:Microbial Sensitivity Tests; D008863:Microspheres; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009693:Nucleic Acid Hybridization / Q000379:methods*; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D017931:DNA Primers; D004269:DNA, Bacterial; D021901:DNA, Intergenic