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Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x.
Antimicrob Agents Chemother. 2018 09; 62(9)AA

Abstract

Colistin is a last-line drug for multidrug-resistant Gram-negative bacteria. We previously reported four plasmid-mediated colistin resistance (mcr) gene-negative colistin-resistant Escherichia coli clinical isolates, including the major pathogenic and fluoroquinolone-resistant strains O25b:H4-ST131-H30Rx (isolates SRE34 and SRE44; MIC for colistin = 16 mg/liter), non-x (SME296; MIC = 8 mg/liter), and O18-ST416 (SME222; MIC = 4 mg/liter). In this study, we investigated the colistin resistance mechanism and identified novel amino acid substitutions or deletions in the PmrAB two-component system that activates eptA (encoding a phosphoethanolamine transferase) and arnT (encoding an undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase) in all colistin-resistant isolates. SRE34 possessed deletion Δ27-45 (LISVFWLWHESTEQIQLFE) in PmrB, SRE44 possessed substitution L105P in PmrA, and both SME222 and SME296 included substitution G206D in PmrB. Matrix-assisted laser desorption ionization-time of flight mass spectrometry revealed that lipid A is modified with phosphoethanolamine in all four isolates. Deletion of pmrAB decreased colistin MICs to 0.5 mg/liter and lowered eptA and arnT expression. Chromosomal replacement of mutated pmrA or pmrB in colistin-susceptible O25b:H4-ST131 strain SME98 (colistin MIC = 0.5 mg/liter) increased the colistin MIC to that of the respective parent colistin-resistant isolate. In addition, SME98 mutants in which pmrAB was replaced with mutated pmrAB showed no significant differences in bacterial growth and competition culture from the parent strain, except for the mutant with L105P in PmrA, whose growth was significantly suppressed in the presence of the parent strain. In conclusion, some O25b:H4-ST131 strains appear to acquire colistin resistance via phosphoethanolamine modification of lipid A through amino acid changes in PmrAB, and the amino acid changes in PmrB do not influence bacterial growth.

Authors+Show Affiliations

Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan sato.t@sapmed.ac.jp.Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan.Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan. Department of Urology, Sapporo Medical University School of Medicine, Sapporo, Japan.Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan. Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan.Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan.Laboratory of Food Microbiology and Food Safety, Department of Health and Environmental Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.Department of Respiratory Medicine and Allergology, Sapporo Medical University School of Medicine, Sapporo, Japan.Department of Urology, Sapporo Medical University School of Medicine, Sapporo, Japan.Division of Laboratory Medicine, Sapporo Medical University Hospital, Sapporo, Japan. Department of Infection Control and Laboratory Medicine, Sapporo Medical University School of Medicine, Sapporo, Japan.Laboratory of Food Microbiology and Food Safety, Department of Health and Environmental Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.Department of Microbiology, Sapporo Medical University School of Medicine, Sapporo, Japan.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

29914952

Citation

Sato, Toyotaka, et al. "Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia Coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x." Antimicrobial Agents and Chemotherapy, vol. 62, no. 9, 2018.
Sato T, Shiraishi T, Hiyama Y, et al. Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x. Antimicrob Agents Chemother. 2018;62(9).
Sato, T., Shiraishi, T., Hiyama, Y., Honda, H., Shinagawa, M., Usui, M., Kuronuma, K., Masumori, N., Takahashi, S., Tamura, Y., & Yokota, S. I. (2018). Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x. Antimicrobial Agents and Chemotherapy, 62(9). https://doi.org/10.1128/AAC.00864-18
Sato T, et al. Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia Coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x. Antimicrob Agents Chemother. 2018;62(9) PubMed PMID: 29914952.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Contribution of Novel Amino Acid Alterations in PmrA or PmrB to Colistin Resistance in mcr-Negative Escherichia coli Clinical Isolates, Including Major Multidrug-Resistant Lineages O25b:H4-ST131-H30Rx and Non-x. AU - Sato,Toyotaka, AU - Shiraishi,Tsukasa, AU - Hiyama,Yoshiki, AU - Honda,Hiroyuki, AU - Shinagawa,Masaaki, AU - Usui,Masaru, AU - Kuronuma,Koji, AU - Masumori,Naoya, AU - Takahashi,Satoshi, AU - Tamura,Yutaka, AU - Yokota,Shin-Ichi, Y1 - 2018/08/27/ PY - 2018/05/01/received PY - 2018/06/02/accepted PY - 2018/6/20/pubmed PY - 2019/10/23/medline PY - 2018/6/20/entrez KW - Escherichia coli KW - PmrAB KW - antimicrobial resistance KW - bacterial infection KW - lipid A JF - Antimicrobial agents and chemotherapy JO - Antimicrob. Agents Chemother. VL - 62 IS - 9 N2 - Colistin is a last-line drug for multidrug-resistant Gram-negative bacteria. We previously reported four plasmid-mediated colistin resistance (mcr) gene-negative colistin-resistant Escherichia coli clinical isolates, including the major pathogenic and fluoroquinolone-resistant strains O25b:H4-ST131-H30Rx (isolates SRE34 and SRE44; MIC for colistin = 16 mg/liter), non-x (SME296; MIC = 8 mg/liter), and O18-ST416 (SME222; MIC = 4 mg/liter). In this study, we investigated the colistin resistance mechanism and identified novel amino acid substitutions or deletions in the PmrAB two-component system that activates eptA (encoding a phosphoethanolamine transferase) and arnT (encoding an undecaprenyl phosphate-alpha-4-amino-4-deoxy-l-arabinose arabinosyl transferase) in all colistin-resistant isolates. SRE34 possessed deletion Δ27-45 (LISVFWLWHESTEQIQLFE) in PmrB, SRE44 possessed substitution L105P in PmrA, and both SME222 and SME296 included substitution G206D in PmrB. Matrix-assisted laser desorption ionization-time of flight mass spectrometry revealed that lipid A is modified with phosphoethanolamine in all four isolates. Deletion of pmrAB decreased colistin MICs to 0.5 mg/liter and lowered eptA and arnT expression. Chromosomal replacement of mutated pmrA or pmrB in colistin-susceptible O25b:H4-ST131 strain SME98 (colistin MIC = 0.5 mg/liter) increased the colistin MIC to that of the respective parent colistin-resistant isolate. In addition, SME98 mutants in which pmrAB was replaced with mutated pmrAB showed no significant differences in bacterial growth and competition culture from the parent strain, except for the mutant with L105P in PmrA, whose growth was significantly suppressed in the presence of the parent strain. In conclusion, some O25b:H4-ST131 strains appear to acquire colistin resistance via phosphoethanolamine modification of lipid A through amino acid changes in PmrAB, and the amino acid changes in PmrB do not influence bacterial growth. SN - 1098-6596 UR - https://www.unboundmedicine.com/medline/citation/29914952/Contribution_of_Novel_Amino_Acid_Alterations_in_PmrA_or_PmrB_to_Colistin_Resistance_in_mcr_Negative_Escherichia_coli_Clinical_Isolates_Including_Major_Multidrug_Resistant_Lineages_O25b:H4_ST131_H30Rx_and_Non_x_ L2 - http://aac.asm.org/cgi/pmidlookup?view=long&pmid=29914952 DB - PRIME DP - Unbound Medicine ER -