RT Journal Article SR Electronic(1) A1 Manohar, Prasanth A1 Shanthini, Thamaraiselvan A1 Ayyanar, Ramankannan A1 Bozdogan, Bulent A1 Wilson, Aruni A1 Tamhankar, Ashok J. A1 Nachimuthu, Ramesh A1 Lopes, Bruno S.YR 2017 T1 The distribution of carbapenem- and colistin-resistance in Gram-negative bacteria from the Tamil Nadu region in India JF Journal of Medical Microbiology, VO 66 IS 7 SP 874 OP 883 DO https://doi.org/10.1099/jmm.0.000508 PB Microbiology Society, SN 1473-5644, AB Purpose. The occurrence of carbapenem- and colistin-resistance among Gram-negative bacteria is increasing worldwide. The aim of this study was to understand the distribution of carbapenem- and colistin-resistance in two areas in Tamil Nadu, India. Methodology. The clinical isolates (n=89) used in this study were collected from two diagnostic centres in Tamil Nadu, India. The bacterial isolates were screened for meropenem- and colistin-resistance. Further, resistance genes bla NDM-1, bla OXA-48-like, bla IMP, bla VIM, bla KPC, mcr-1 and mcr-2 and integrons were studied. The synergistic effect of meropenem in combination with colistin was assessed. Results. A total of 89 bacterial isolates were studied which included Escherichia coli (n=43), Klebsiella pneumoniae (n=18), Pseudomonas aeruginosa (n=10), Enterobacter cloacae (n=6), Acinetobacter baumannii (n=5), Klebsiella oxytoca (n=4), Proteus mirabilis (n=2) and Salmonella paratyphi (n=1). MIC testing showed that 58/89 (65 %) and 29/89 (32 %) isolates were resistant to meropenem and colistin, respectively, whereas 27/89 (30 %) isolates were resistant to both antibiotics. Escherichia coli, K. pneumoniae, K. oxytoca, Pseudomonas aeruginosa, and Enterobacter cloacae isolates were bla NDM-1-positive (n=20). Some strains of Escherichia coli, K. pneumoniae and K. oxytoca were bla OXA-181-positive (n=4). Class 1, 2 and 3 integrons were found in 24, 20 and 3 isolates, respectively. Nine NDM-1-positive Escherichia coli strains could transfer carbapenem resistance via plasmids to susceptible Escherichia coli AB1157. Meropenem and colistin showed synergy in 10/20 (50 %) isolates by 24 h time-kill studies. Conclusion. Our results highlight the distribution of carbapenem- and colistin-resistance in Gram-negative bacteria isolated from the Tamil Nadu region in South India., UL https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000508