Species-level identification of Acinetobacter by 16s rRNA sequencing: Necessity today, essentiality tomorrow

Abstract

Purpose: When common organisms present with uncommon phenotypes, reliance on phenotype can compromise accurate identification. The use of 16s rRNA gene sequences to study bacterial phylogeny, and taxonomy has been the most common housekeeping genetic marker. The aim of our study was to identify "difficult" and notorious uropathogen such as Acinetobacter through multiple identification methods. Materials and Methods: The present prospective study was conducted for the period of 6 months in the year 2015 in the Department of Microbiology of a Teaching Tertiary Care Hospital. A total of 345 clean catch, midstream urine samples obtained from patients suspected of urinary tract infection were subjected to microscopy and culture. Uropathogens isolated from the culture-positive samples were identified to species level through conventional, automated, and molecular methods. Results: A total of 123 uropathogens were isolated from 118 culture-positive samples. Among them, 81.3% isolates were Gram-negative bacteria, 14.6% were Gram-positive bacteria, and 23.5% were Candida species. Four (3.2%) Acinetobacter isolates were detected among which three were confirmed as Acinetobacter baumannii, whereas one of them was confirmed as Acinetobacter junii by different methods of identification. Conclusion: Identification by gene sequencing is more objective, reliable, reproducible, and accurate and has the capability of defining taxonomical relations among bacteria.