Development of novel antibodies for detection of mobile colistin-resistant bacteria contaminated in meats

Xiaohua He,Stephanie Patfield,Fernando M Rubio,Daniela Mavrici

doi:10.1038/s41598-018-34764-2

Xiaohua He, Stephanie Patfield + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-34764-2

Copy DOI

Abstract

The recent discovery and rapid spread of mobile colistin-resistant gene, mcr-1, among bacteria isolated from a broad range of sources is undermining our ability to treat bacterial infections and threatening human health and safety. To prevent further transfer of colistin resistance, practical and reliable methods for mcr-1-containing bacteria are need. In this study, standards and novel polyclonal and monoclonal antibodies (mAbs) against MCR-1 were developed. Among nine mAbs, three were MCR-1 specific and six cross-reacted with both MCR-1 and MCR-2. A sandwich enzyme-linked immunosorbent assay (ELISA) was established using the polyclonal antibody as a capturer and the mAb MCR-1-7 as a detector. The assay had a limit of detection of 0.01 ng/mL for MCR-1 and 0.1 ng/mL for MCR-2 in buffer with coefficients of variation (CV) less than 15%. When applied to ground beef, chicken and pork, this ELISA identified samples inoculated with less than 0.4 cfu/g of meat, demonstrating its strong tolerance to complex food matrices. To our knowledge, this is the first immunoassay developed for MCR-1 and MCR-2. It should be useful for prompt and reliable screening of meat samples contaminated with plasmid-borne colistin-resistant bacteria, thus reducing human risk of foodborne infections with possibly no antibiotic treatment options.

Highlights

Colistin, known as polymyxin E, is a bactericidal antibiotic with a broad Gram-negative spectrum
Our results indicate that the enzyme-linked immunosorbent assay (ELISA) was highly sensitive, specific and has strong tolerance to complex food matrices, such as ground beef, chicken and pork, which is extremely valuable because colistin is widely used for controlling diarrheal diseases in cow, pig and poultry production[30], and high prevalence of colistin-resistant bacteria has already been found in these food animals[6,31,32]
The recent emergence of mobile colistin-resistance in bacteria is of extreme concern as colistin is one of the last line antibiotics effective for severe infections caused by multidrug resistant bacteria

Summary

Introduction

Known as polymyxin E, is a bactericidal antibiotic with a broad Gram-negative spectrum. This gene can spread from one type of bacteria to another[4] It encodes a phosphoethanolamine (PEA) transferase that catalyzes the addition of cationic PEA to lipid A component of LPS, reducing the negative charge of the cell surface such that the cationic colistin is unable to bind and initiate membrane lysis[5]. Plasmid-borne mcr-1 has been found in bacteria isolated from various food animals, the environment, vegetables and patients and spread onto at least five continents and more than 40 countries[6,7,8] This resistance mechanism has even extended to carbapenemase-producing Enterobacteriaceae that are resistant to the carbapenem class of antibiotics, considered the drugs of last resort for such infections[9]. Our results indicate that the ELISA was highly sensitive, specific and has strong tolerance to complex food matrices, such as ground beef, chicken and pork, which is extremely valuable because colistin is widely used for controlling diarrheal diseases in cow, pig and poultry production[30], and high prevalence of colistin-resistant bacteria has already been found in these food animals[6,31,32]

Methods

Results

Conclusion