Phenotypic and molecular characterization of clinical isolates of Acinetobacter baumannii isolated from Delhi, India.
BACKGROUND
Acinetobacter has gained importance as a multi-drug resistant and hence a difficult to treat pathogen. This study was done to characterize our isolates with respect to drug resistance and presence of beta-lactamases which is a major mechanism of resistance and to type using RAPD and MLST so that comparison of our clones can be made with the existing international clones.


METHODS
100 isolates recovered from clinical samples from two hospitals in Delhi were tested for their susceptibility against major groups of antimicrobials. The resistant isolates were screened and confirmed phenotypically for presence of ESBL, MBL and AmpC and MBLs also by PCR. The isolates were typed by RAPD and MLST.


RESULTS
Out of the 100 isolates, 91, 78 and 2 % were MDR, XDR and PDR respectively. 97, 100 and 85 were screen positive for ESBL, AmpC and MBL respectively. Of these, 38.1 % were confirmed phenotypically to produce ESBL, 99 % produced AmpC and 29.4 % produced MBL comprising of GIM, VIM, SIM and IMP. MLST showed known STs 110, 188, 146, 69, 103, 108 and 194. Eight new STs were encountered. The RAPD showed a high degree of genetic variability among the isolates.


CONCLUSIONS
Majority of our isolates were MDR, producing one or more types of beta-lactamases. We encountered drug resistant international clones by MLST which are found in other continents there by confirming their spread to Indian sub continent. No data on ST types of other Indian isolates is available in the MLST database and hence comparison is not possible.
Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, 110007, India. dabetrynga@gmail.com.|Department of Microbiology, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, India. dabetrynga@gmail.com.
Dabet
D
Rynga
Department of Microbiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi, 110007, India. malini.shariff@gmail.com.
Malini
M
Shariff
Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, 110029, India. dr.manoramadeb@yahoo.com.
Monorama
M
Deb
D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007194:India / Q000453:epidemiology; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D010641:Phenotype; D019105:Random Amplified Polymorphic DNA Technique; D001618:beta-Lactamases / Q000378:metabolism
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases