ABSTRACT
Acinetobacter species are non-fermentative Gram-negative coccobacilli and they have emerged as important nosocomial pathogens which are associated with the significant multidrug resistance in recent years. Carbapenem-resistant A. baumannii (CRAB) and pandrug-resistant A. baumannii (PDRAB) were reported in 1991 and 1998, respectively. Fiftyeight isolates of Acinetobacter species recovered from a university hospital between August 2004 and March 2005 were investigated for the existence of CRAB, PDRAB, extended-spectrum beta-lactamase (ESBL)-producing Acinetobacter and examined for their phenotypic and genotypic characteristics. Genomospecies of Acinetobacter species were determined by amplified rDNA restriction analysis (ARDRA) and antimicrobial susceptibility test was performed with 13 kinds of antimicrobial agents. Metallo-beta-lactamase (MBL) producers were screened by modified hodge test and confirmed by imipenem-EDTA disk synergy test. Detection of blaIMP-1, blaVIM-2, blaTEM, and blaPER-1 was performed by PCR. Genomic DNAs were analyzed by pulsed-field gel electrophoresis (PFGE). Among 58 isolates of Acinteobacter species, 40 isolates were identified as genospecies 2 (A. baumannii), 9 were 13TU, 5 were A. phenon 6/ct, and 4 were Acinetobacter genospecies 3 by ARDRA. Thirteen isolates were confirmed as MBL-producers and blaIMP-1 and blaVIM-2 were carried by 5 and 8 isolates of them, respectively. MBL-producers were mostly 13TU, A. phenon 6/ct 13TU, and Acinetobacter genospecies 3 and they were susceptible to ciprofloxacin and ampicillin-sulbactam. BlaPER-1 was carried by thirteen isolates and 12 isolates of them were PDRAB showing resistance to all antimicrobial agents tested, including ceftazidime, cefepime, aztreonam, ciprofloxacin, amikacin, gentamicin, ampicillin-sulbactam, and imipenem. In conclusion, most MBL-producers belonged to 13TU, A. phenon 6/ct 13TU, and Acinetobacter genospecies 3 which were susceptible to ciprofloxacin and ampicillin-sulbactam, whereas 12 of 13 PER-1-producers were PDRAB originated from the same clone.
Subject(s)
Acinetobacter , Amikacin , Anti-Infective Agents , Aztreonam , beta-Lactamases , Ceftazidime , Ciprofloxacin , Clone Cells , DNA , DNA, Ribosomal , Drug Resistance, Multiple , Electrophoresis, Gel, Pulsed-Field , Gentamicins , Imipenem , Polymerase Chain ReactionABSTRACT
Acinetobacter species are non-fermentative Gram-negative coccobacilli and they have emerged as important nosocomial pathogens which are associated with the significant multidrug resistance in recent years. Carbapenem-resistant A. baumannii (CRAB) and pandrug-resistant A. baumannii (PDRAB) were reported in 1991 and 1998, respectively. Fiftyeight isolates of Acinetobacter species recovered from a university hospital between August 2004 and March 2005 were investigated for the existence of CRAB, PDRAB, extended-spectrum beta-lactamase (ESBL)-producing Acinetobacter and examined for their phenotypic and genotypic characteristics. Genomospecies of Acinetobacter species were determined by amplified rDNA restriction analysis (ARDRA) and antimicrobial susceptibility test was performed with 13 kinds of antimicrobial agents. Metallo-beta-lactamase (MBL) producers were screened by modified hodge test and confirmed by imipenem-EDTA disk synergy test. Detection of blaIMP-1, blaVIM-2, blaTEM, and blaPER-1 was performed by PCR. Genomic DNAs were analyzed by pulsed-field gel electrophoresis (PFGE). Among 58 isolates of Acinteobacter species, 40 isolates were identified as genospecies 2 (A. baumannii), 9 were 13TU, 5 were A. phenon 6/ct, and 4 were Acinetobacter genospecies 3 by ARDRA. Thirteen isolates were confirmed as MBL-producers and blaIMP-1 and blaVIM-2 were carried by 5 and 8 isolates of them, respectively. MBL-producers were mostly 13TU, A. phenon 6/ct 13TU, and Acinetobacter genospecies 3 and they were susceptible to ciprofloxacin and ampicillin-sulbactam. BlaPER-1 was carried by thirteen isolates and 12 isolates of them were PDRAB showing resistance to all antimicrobial agents tested, including ceftazidime, cefepime, aztreonam, ciprofloxacin, amikacin, gentamicin, ampicillin-sulbactam, and imipenem. In conclusion, most MBL-producers belonged to 13TU, A. phenon 6/ct 13TU, and Acinetobacter genospecies 3 which were susceptible to ciprofloxacin and ampicillin-sulbactam, whereas 12 of 13 PER-1-producers were PDRAB originated from the same clone.