Molecular characterization and clinical significance of New Delhi metallo-beta-lactamases-1 producing Escherichia coli recovered from a South Indian tertiary care hospital

• Main Authors: Arindam Ckakraborty, Prabha Adhikari, Shalini Shenoy, Shrikala Baliga, Gopalkrishna Bhat, Satish Rao, Dhanashree Biranthabail, Vishwas Saralaya
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2015-01-01
• Series: Indian Journal of Pathology and Microbiology
• Subjects: Drug resistance; Escherichia coli; New Delhi metallo-beta-lactamases-1; phylogroups
• Online Access: http://www.ijpmonline.org/article.asp?issn=0377-4929;year=2015;volume=58;issue=3;spage=323;epage=327;aulast=Ckakraborty

Context: The increased rate of infection by New Delhi metallo-beta-lactamases-1 (NDM1) producing Escherichia coli is a major concern since they show a high rate of drug resistance and are responsible for mortality and morbidity. Aims: To characterize the NDM1 producing E. coli isolates and their impact on patients′ clinical outcome. Settings and Design: This descriptive study was carried out in a multi-specialty tertiary care hospital. Materials and Methods: Three hundred nonrepeat strains of E. coli from inpatients were included in the study. Modified Hodge test and metallo-beta-lactamases (MBL) e-test were performed to detect carbapenemase and MBL activity. Polymerase chain reaction (PCR) technique was performed to detect NDM1. NDM1 positive isolates were further tested for plasmid mediated AmpC, blaCTX , blaSHV , blaTEM genes and also for phylogrouping by PCR methods. Treatment and patients′ clinical outcome were also analyzed. Results: Out of 300 isolates, 21 (7%) were MBL producers by phenotypic methods. Of this, 17 (81%) were NDM1 positives, among the NDM1 producers 6 (35%) isolates were belongs to phylogroups D followed by A 5 (29%), B1 4 (24%) and B2 2 (12%), 15 (88%) isolates were blaCTX-M positive suggestive of extended-spectrum beta lactamase producing strain and 7 (47%) were positive with CIT type of AmpC. With the follow-up of the patients, it was found that 12 (71%) recovered and 3 (18%) developed relapses, and mortality was seen in 2 (12%) patients. Conclusions: NDM1 producing isolates showed a high degree of drug resistance but can be treated with suitable antimicrobials, in the majority. Early detection and choice of appropriate antibiotics may help in reducing mortality and morbidity.