Abstract
Objectives: To establish the ecological correlation between the Acinetobacter baumannii isolates by performing Multilocus Sequence typing
Material and methods:A total of 181 isolates (Sputum (116), lower respiratory tract other than sputum (36), upper respiratory tract (20), Environment (medical) 4, and Blood (5)) of Acinetobacter baumannii were retrieved from our repository. DNA was isolated and Multilocus Sequence Typing was performed according to the Pasteur scheme. The amplified fragments were sequenced by outsourcing, and the locus and the sequence types were determined as given in the PUBMLST site. The clonal complexes were assigned using eBURST.
Results and Conclusion:
Out of the 181 isolates, 20 were colonizers and 4 were from hospital environment. All the study isolates except 4 were multidrug resistant. 23 sequence types were unique and were assigned new sequence types. Among them, 2125 (n=12), an SLV of 2, was the commonest followed by 2126 (n=2) which was a DLV of 2 and SLV of 2125. Others were singletons. Among the known STs 149 (n=72) was the commonest followed by ST 2 (n=62) & 415(5), ST 10 (n=4), ST 15, ST622 and ST1482 (3 each). ST149 had 1SLV ST1482 (3). ST 2 has 5 SLVs (415, 1555, 2125, 2128, & 2131, and 2 DLVs (2130 & 2126). eBURST analysis of the study isolates showed three groups Group I (86 isolates) with ST 2 as the primary founder, group II (6 isolates) and group 3 (79 isolates) with ST 149 as the primary founder. All the other 10 isolates were singletons. There was no difference in antimicrobial sensitivity or sequence types of the clinical and colonizing isolates. The sequence types of the study isolates were compared to the world isolates in the PUBMLST database.