Dielectrophoresis System for Testing Antimicrobial Susceptibility of Gram-Negative Bacteria to β-Lactam Antibiotics.
Gram-negative bacteria (GNBs) are common pathogens causing severe sepsis. Rapid evaluation of drug susceptibility would guide effective antibiotic treatment and promote life-saving. A total of 78 clinical isolates of 13 Gram-negative species collected between April 2013 and November 2013 from two medical centers in Tainan were tested. Bacterial morphology changes in different concentrations of antibiotics were observed under the electric field of a quadruple electrode array using light microscopy. The minimal inhibitory concentrations (MICs) of four antimicrobial agents, namely, cefazolin, ceftazidime, cefepime, and doripenem, were determined by the dielectrophoretic antimicrobial susceptibility testing (dAST) and by the conventional broth dilution testing (BDT). The antibiotics at the concentration of 1× MIC induced obvious morphological changes in susceptible GNBs, including cell elongation, cell swelling, or lysis, at 90 min. In contrast, resistant strains remained unchanged. The MIC results measured by dAST were in good agreement with those of BDT (essential agreement 95.6%). The category agreement rate was 89.2%, and the very major errors rate for dAST was 2.9%. In conclusion, dAST could accurately determine drug susceptibility within 90 min. Comprehensive tests by dAST for more drugs against more GNB species are possible in the future.
Department of Biomedical Engineering, National Cheng Kung University , Tainan 70101, Taiwan.
I-Hsiu
IH
Su
Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University , Tainan 70101, Taiwan.
Wen-Chien
WC
Ko
Department of Biomedical Engineering, National Cheng Kung University , Tainan 70101, Taiwan.
Chung-Hsin
CH
Shih
Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University , Tainan 70101, Taiwan.
Fang-Hao
FH
Yeh
Department of Computer Science and Information Engineering, National Cheng Kung University , Tainan 70101, Taiwan.
Yung-Nien
YN
Sun
Institute of Biomedical Engineering, National Chiao Tung University , Hsinchu 30010, Taiwan.
Jung-Chih
JC
Chen
Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University , Tainan 70101, Taiwan.
Po-Lin
PL
Chen
Department of Biomedical Engineering, National Cheng Kung University , Tainan 70101, Taiwan.
Hsien-Chang
0000-0001-7874-1712
HC
Chang
D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D002437:Cefazolin / Q000737:chemistry / Q000494:pharmacology; D000077723:Cefepime / Q000737:chemistry / Q000494:pharmacology; D002442:Ceftazidime / Q000737:chemistry / Q000494:pharmacology; D000077726:Doripenem / Q000737:chemistry / Q000494:pharmacology; D004566:Electrodes; D004586:Electrophoresis / Q000379:methods*; D006090:Gram-Negative Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D006801:Humans; D008826:Microbial Sensitivity Tests; D008853:Microscopy; D047090:beta-Lactams / Q000737:chemistry* / Q000494:pharmacology
D000890:Anti-Infective Agents; D047090:beta-Lactams; D000077723:Cefepime; D002442:Ceftazidime; D000077726:Doripenem; D002437:Cefazolin