[Source: Antimicrobial Agents and Chemotherapy, full text: (LINK). Abstract, edited.]
Multi-resistant uropathogenic Escherichia coli from an endemic zone of urinary tract infections in India: genotypic and phenotypic characteristics of ST131 isolates of the CTX-M-15 Extended-Spectrum-Beta-Lactamase producing lineage

Arif Hussain 1, Christa Ewers 2,3, Nishant Nandanwar 2, Sebastian Guenther 2, Savita Jadhav 4, Lothar H. Wieler 2 and Niyaz Ahmed 1,5,*

Author Affiliations: <SUP>1</SUP>Pathogen Biology Laboratory, Department of Biotechnology, School of Life Sciences, University of Hyderabad, Hyderabad, India <SUP>2</SUP>Faculty of Veterinary Medicine, Institute for Microbiology and Epizootics, Freie Universitaet Berlin, Berlin, Germany <SUP>3</SUP>Faculty of Veterinary Medicine, Institute for Hygiene and Infectious Diseases of Animals, Justus-Liebig-Universitaet Giessen, Germany <SUP>4</SUP>Department of Microbiology, Dr. D. Y. Patil Medical College and Hospital, Pimpri, Pune, India <SUP>5</SUP>Institute of Biological Sciences, University of Malaya, Kuala Lumpur, Malaysia


Escherichia coli sequence type ST131 (O25b:H4), associated with the CTX-M-15 extended-spectrum beta-lactamases (ESBLs) and linked predominantly to the community-onset antimicrobial resistant infections has globally emerged as a public health concern. However, scant attention is given to the understanding of the molecular epidemiology of these strains in high burden countries such as India. Of the 100 clinical E. coli isolates obtained by us from an endemic setting, 16 ST131 E. coli isolates were identified by multilocus sequence typing (MLST). Further, genotyping and phenotyping methods were employed to characterize their virulence and drug resistance patterns. All the 16 ST131 isolates harbored CTX-M-15 gene and half of them also carried TEM-1; 11 of these were positive for bla<SUB>OXA</SUB> group 1 and 12 for aac(6? )-Ib-cr. At least 12 isolates were refractory to four non beta-lactam antibiotics: ciprofloxacin, gentamicin, sulfamethoxazole/trimethoprime and tetracycline. Nine isolates carried the class 1 integron. Plasmid analysis indicated a large pool of up to six plasmids per strain with a mean of ∼three plasmids. Conjugation and PCR-based replicon typing (PBRT) revealed that the spread of resistance was associated with FIA incompatibility group of plasmids. Pulsed-field gel electrophoresis (PFGE) and genotyping of the virulence genes showed a low level of diversity among these strains. The association of ESBL-encoding plasmid with virulence was demonstrated in transconjugants by serum assay. None of the 16 ST131 ESBL-producing E. coli was known to synthesize carbapenemase enzymes.

In conclusion, our study reports a snapshot of the highly virulent/multiresistant clone ST131 of uropathogenic E. coli from India. This study suggests that the ST131 genotypes from this region are clonally evolved and are strongly associated with CTX-M-15 enzyme, carry a high antibiotic resistance background, and have emerged as an important cause of community-acquired urinary tract infections.


* Corresponding author. Mailing address: Pathogen Biology Laboratory, Department of Biotechnology, School of Life Sciences, University of Hyderabad, Professor CR Rao Road, Gachibowli, Hyderabad 500 046, India. Phone: 91 40 23134585. Fax: 91 40 66794585. Email. ahmed.nizi@gmail.com

Copyright ? 2012, American Society for Microbiology. All Rights Reserved.
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