Molecular Mechanisms of Colistin- and Multidrug-Resistance in Bacteria Among Patients with Hospital-Acquired Infections

Abstract

Aim: The increasing burden of resistance in Gram-negative bacteria (GNB) is becoming a major issue for hospital-acquired infections. Therefore, understanding the molecular mechanisms is important. Methodology: Resistance genes of phenotypically colistin-resistant GNB (n = 60) were determined using whole genome sequencing. Antimicrobial susceptibility patterns were detected by Vitek®2 & broth microdilution. Results: Of these phenotypically colistin-resistant isolates, 78% were also genetically resistant to colistin. Activation of efflux pumps, and point-mutations in pmrB, and MgrB genes conferred colistin resistance among GNB. Eight different strains of K. pneumoniae were identified and ST43 was the most prominent strain with capsular type-specific (cps) gene KL30. Discussion: These results, in combination with rapid diagnostic methods, will help us better advice appropriate antimicrobial regimens.

Keywords:

• antimicrobial resistance
• colistin-resistant bacteria
• hospital-acquired infections
• multidrug resistance
• whole genome sequencing

Author contributions

S Khurana: experimentation, data analysis, manuscript writing & reviewing, formal analysis; A Katiyar: data curation and analysis; M Puraswani and D Sharma: writing, reviewing and formal analysis; K Walia and R Malhotra: conceptualization reviewing and supervision; P Mathur: conceptualization, writing, reviewing, funding acquisition, visualization, supervision, project administration, validation, formal analysis, investigation, resources.

Acknowledgments

This study was conducted at the Center of Advanced Research (CAR) in hospital-acquired infections- Prevention and Control, funded by the Indian Council of Medical Research, New Delhi, India. (grant no. I-1203).

Financial & competing interests disclosure

This study was supported by a grant from the Indian Council of Medical Research (project code I-1203). The authors acknowledge the technical and financial support of ICMR. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.