Niranjana Mahalingam1,2, Bhavani Manivannan1,2, Balaram Khamari2, Shivakumara Siddaramappa3, Sudeshna Adak4, Eswarappa Pradeep Bulagonda2. 1. Department of Microbiology, Sri Sathya Sai Institute of Higher Medical Sciences, Puttaparthi, India. 2. Department of Biosciences, Sri Sathya Sai Institute of Higher Learning, Puttaparthi, India. 3. Institute of Bioinformatics and Applied Biotechnology, Bengaluru, India. 4. OMIX Research and Diagnostics Laboratories Private Limited, Bengaluru, India.
Abstract
OBJECTIVES: The aim of this study was to analyze the prevalence of the CTX-M, TEM, SHV, VIM, NDM, and OXA genes in carbapenemase-producing Escherichia coli and their transmissibility at a tertiary care hospital in south India. MATERIALS AND METHODS: Twenty-one carbapenem-resistant E. coli (carbapenem-resistant Enterobacteriaceae; CRE) were collected from the Sri Sathya Sai Institute of Higher Medical Sciences (Puttaparthi India). Resistance to antibiotics was analyzed by Vitek-2, and the identity of the isolates was confirmed by 16S rDNA sequencing. RAPD and enterobacterial repetitive intergenic consensus (ERIC)-PCR were performed for molecular typing. Metallo-β-lactamase production was confirmed by a double disc synergy test. The presence of the extended-spectrum β-lactamases CTX-M, TEM, and SHV and of the carbapenemases NDM, VIM, and OXA was determined by PCR. Carbapenemase variants were further confirmed by sequencing. The transmissibility of the genes was tested by conjugation. RESULTS: Twelve of the 21 (57%) carbapenem-resistant E. coli isolates were community acquired, indicating the spread of CRE in environmental samples. TEM and NDM-5 were found to be the major β-lactamases produced by the pathogens. OXA-181 was found in 5 of the isolates. All 21 isolates were found to harbor more than one of the tested β-lactamases, and all of the isolates were found to have the capacity to participate in conjugation; 15 of the transconjugants were found to have acquired the tested β-lactamases, substantiating their ability to be transferred to other strains of bacteria. CONCLUSION: Monitoring of community-acquired carbapenem-resistant bacteria is very important as the association of resistance determinants with mobile genetic elements would present a serious clinical challenge.
OBJECTIVES: The aim of this study was to analyze the prevalence of the CTX-M, TEM, SHV, VIM, NDM, and OXA genes in carbapenemase-producing Escherichia coli and their transmissibility at a tertiary care hospital in south India. MATERIALS AND METHODS: Twenty-one carbapenem-resistant E. coli (carbapenem-resistant Enterobacteriaceae; CRE) were collected from the Sri Sathya Sai Institute of Higher Medical Sciences (Puttaparthi India). Resistance to antibiotics was analyzed by Vitek-2, and the identity of the isolates was confirmed by 16S rDNA sequencing. RAPD and enterobacterial repetitive intergenic consensus (ERIC)-PCR were performed for molecular typing. Metallo-β-lactamase production was confirmed by a double disc synergy test. The presence of the extended-spectrum β-lactamases CTX-M, TEM, and SHV and of the carbapenemases NDM, VIM, and OXA was determined by PCR. Carbapenemase variants were further confirmed by sequencing. The transmissibility of the genes was tested by conjugation. RESULTS: Twelve of the 21 (57%) carbapenem-resistant E. coli isolates were community acquired, indicating the spread of CRE in environmental samples. TEM and NDM-5 were found to be the major β-lactamases produced by the pathogens. OXA-181 was found in 5 of the isolates. All 21 isolates were found to harbor more than one of the tested β-lactamases, and all of the isolates were found to have the capacity to participate in conjugation; 15 of the transconjugants were found to have acquired the tested β-lactamases, substantiating their ability to be transferred to other strains of bacteria. CONCLUSION: Monitoring of community-acquired carbapenem-resistant bacteria is very important as the association of resistance determinants with mobile genetic elements would present a serious clinical challenge.
Authors: Mariana Castanheira; Lalitagauri M Deshpande; Dilip Mathai; Jan M Bell; Ronald N Jones; Rodrigo E Mendes Journal: Antimicrob Agents Chemother Date: 2010-12-28 Impact factor: 5.191
Authors: Jesús Rodríguez-Baño; Juan C Alcalá; Jose M Cisneros; Fabio Grill; Antonio Oliver; Juan P Horcajada; Teresa Tórtola; Beatriz Mirelis; Gemma Navarro; María Cuenca; María Esteve; Carmen Peña; Ana C Llanos; Rafael Cantón; Alvaro Pascual Journal: Arch Intern Med Date: 2008-09-22