C2-3924. Emergence and Dissemination of Enterobacteriaceae with Plasmidic CMY-2,CMY-6, and DHA-1 AmpC Beta-Lactamases in India: First Report
Session: Poster Session: Surveys of Resistance Trends in Enterobacteriaceae
Tuesday, October 28, 2008: 12:00 AM
Room: Hall C
Background: Due to paucity of Indian literature, the present study was designed to determine the prevalence of plasmidic AmpC beta-lactamases and prevalent genotypes. Methods: 242 bacterial isolates including 176 E. coli and 66 K. pneumoniae resistant to any of the third generation cephalosporins (3GC) and obtained during 2005-2007 were studied. Detailed antibiotics susceptibility was performed and all isolates were screened for blaampC using multiplex PCR. Representative isolates were sequenced to know the existing AmpC types. IS26 PCR and RAPD-typing were also performed. Results: 129 (53.3%) of 242 3GC resistant isolates were resistant to cefoxitin. Concomitant high resistance to 3GC, 4GC, aztreonam, gentamicin, trimethoprim and ciprofloxacin was noticed. All 129 isolates were multidrug resistant, majority (59/129) being resistant to 10 out of 12 drugs tested. A total of 23.6% (57/242) isolates (23 E.coli and 34 K. pneumoniae) carried plasmidic blaampC of CIT-family. While one E. coli isolate (0.41%) carried plasmidic blaampC of DHA-family. Among the cefoxitin-resistant isolates, presence of plasmidic blaampC was noticed in 41.1% (53/129) isolates. Five isolates carrying blaampC fell in cefoxitin susceptible range. Sequencing of the representative isolates revealed CMY-2, CMY-6, and DHA-1 AmpC-beta-lactamases. Amplicons of varying sizes were produced in IS26 PCR, some producing ~1400 bp amplicons. RAPD typing revealed the presence of diverse bacterial population. Conclusions: Cefoxitin resistance is high, and significant (24%; 57 isolates with CIT-family and one with DHA-family) isolates carried plasmidic-blaampC in Indian Enterobacteriaceae. This is amongst the premier report describing the occurrence of CMY-2 and CMY-6 beta-lactamases and the first report describing the emergence of DHA-1 in India. No single clone but diverse bacterial population exists.
Abida Malik, MD1, Anuradha Singh, MSc1, Farukh Sobia, MSc1, Fatima Shujatullah, MD1, Haris Khan, MD1, Mohd. Shahid, MD, PhD2 and  M. Shahid, None., (1)Aligarh Muslim University, (2)Aligarh Muslim University, Aligarh, India