Molecular Methods for Identification of Acinetobacter Species by Partial Sequencing of the rpoB and 16S rRNA Genes
Background: Acinetobacter spp. is a diverse group of Gramnegative bacteria which are ubiquitous in soil and water, and an important cause of nosocomial infections. The purpose of this study was to identify a collection of Acinetobacter spp. clinical isolates accurately and to investigate their an...
Main Authors: | , , , , |
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Format: | Article |
Language: | English |
Published: |
JCDR Research and Publications Private Limited
2015-07-01
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Series: | Journal of Clinical and Diagnostic Research |
Subjects: | |
Online Access: | https://jcdr.net/articles/PDF/6188/13867_CE(Ra1)_F(GH)_PF1(AGAK)_PFA(AK)_PF2(PAG).pdf |
Summary: | Background: Acinetobacter spp. is a diverse group of Gramnegative bacteria which are ubiquitous in soil and water, and
an important cause of nosocomial infections. The purpose of
this study was to identify a collection of Acinetobacter spp.
clinical isolates accurately and to investigate their antibiotic
susceptibility patterns.
Materials and Methods: A total of 197 non-duplicate
clinical isolates of Acinetobacter spp. isolates identified using
conventional biochemical tests. The molecular technique
of PCR-RFLP and sequence analysis of rpoB and 16S rRNA
genes was applied for species identification. Antimicrobial
susceptibility test was performed with a disk diffusion assay.
Results: Based on 16S rRNA and rpoB genes analysis
separately, most of clinical isolates can be identified with high
bootstrap values. However, the identity of the isolate 555T was
uncertain due to high similarity of A. grimontii and A. junii.
Identification by concatenation of 16S rRNA and rpoB confirmed
the identity of clinical isolates of Acenitobacer to species level
confidently. Accordingly, the isolate 555T assigned as A. grimontii
due to 100% similarity to A. grimontii. Moreover, this isolate
showed 98.64% to A. junii. Besides, the identity of the isolates
218T and 364T was confirmed as Genomic species 3 and A.
calcoaceticus respectively. So, the majority of Acinetobacter
spp. isolates, were identified as: A. baumannii (131 isolates,
66%), A. calcoaceticus (9 isolates, 4.5%), and A. genomosp 16
(8 isolates, 4%). The rest of identified species showed the lower
frequencies. In susceptibility test, 105 isolates (53%), presented
high antibiotic resistance of 90% to ceftriaxone, piperacillin,
piperacillin tazobactam, amikacin, and 81% to ciprofloxacin.
Conclusion: Sequence analysis of the 16S rRNA and rpoB spacer
simultaneously was able to do identification of Acinetobacter
spp. to species level. A.baumannii was identified as the most
prevalent species with high antibiotic resistance. Other species
showed lower frequencies ranged from 4 to 9 strains. |
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ISSN: | 2249-782X 0973-709X |