@article{mbs:/content/journal/jmm/10.1099/jmm.0.000508, author = "Manohar, Prasanth and Shanthini, Thamaraiselvan and Ayyanar, Ramankannan and Bozdogan, Bulent and Wilson, Aruni and Tamhankar, Ashok J. and Nachimuthu, Ramesh and Lopes, Bruno S.", title = "The distribution of carbapenem- and colistin-resistance in Gram-negative bacteria from the Tamil Nadu region in India", journal= "Journal of Medical Microbiology", year = "2017", volume = "66", number = "7", pages = "874-883", doi = "https://doi.org/10.1099/jmm.0.000508", url = "https://www.microbiologyresearch.org/content/journal/jmm/10.1099/jmm.0.000508", publisher = "Microbiology Society", issn = "1473-5644", type = "Journal Article", keywords = "transferability", keywords = "New Delhi metallo-beta lactamases", keywords = "carbapenemases", keywords = "plasmid-bound resistance", keywords = "Integron", abstract = " 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.", }