Intestinal carriage of colistin resistant Enterobacteriaceae in hospitalized patients from an Indian center

Area of Science:

• Microbiology
• Infectious Diseases
• Antimicrobial Resistance

Background:

• Limited data exists on colistin-resistant (Col-R) bacteria gut colonization in India.
• Colistin is a crucial last-resort antibiotic, making Col-R bacteria a significant public health concern.

Purpose of the Study:

• To determine the stool carriage rate of Col-R bacteria in hospitalized patients in India.
• To characterize the resistance mechanisms, including mcr-1 and mgrB mutations, in Col-R Enterobacteriaceae.

Main Methods:

• Stool samples were cultured on Eosin Methylene Blue agar with colistin.
• Colistin minimum inhibitory concentrations (MICs) were determined using broth microdilution.
• PCR for mcr-1, mgrB gene analysis, and whole-genome sequencing for mcr-1 positive E. coli were performed.

Main Results:

• Colistin-resistant bacteria were detected in 51% (33/65) of hospitalized patients' stool samples.
• The majority of Col-R isolates (76.7%) were sensitive to carbapenems.
• mcr-1 gene was detected in some isolates, indicating a common resistance mechanism.

Conclusions:

• A high prevalence of Col-R bacteria gut colonization exists in hospitalized Indian patients.
• Carbapenems remain a viable treatment option for many Col-R infections in this cohort.
• Further surveillance of Col-R bacteria and resistance mechanisms is essential.