TY - JOUR
T1 - A prospective study of acinetobacter baumannii complex isolates and colistin susceptibility monitoring by mass spectrometry of microbial membrane glycolipids
AU - Leung, Lisa M.
AU - McElheny, Christi L.
AU - Gardner, Francesca M.
AU - Chandler, Courtney E.
AU - Bowler, Sarah L.
AU - Mettus, Roberta T.
AU - Spychala, Caressa N.
AU - Fowler, Erin L.
AU - Opene, Belita N.A.
AU - Myers, Robert A.
AU - Goodlett, David R.
AU - Doi, Yohei
AU - Ernst, Robert K.
N1 - Publisher Copyright:
Copyright © 2019 American Society for Microbiology. All Rights Reserved.
PY - 2019/3
Y1 - 2019/3
N2 - Acinetobacter baumannii is a prevalent nosocomial pathogen with a high incidence of multidrug resistance. Treatment of infections due to this organism with colistin, a last-resort antibiotic of the polymyxin class, can result in the emergence of colistin-resistant strains. Colistin resistance primarily occurs via modifications of the terminal phosphate moieties of lipopolysaccharide-derived lipid A, which reduces overall membrane electronegativity. These modifications are readily identified by mass spectrometry (MS). In this study, we prospectively collected Acinetobacter baumannii complex clinical isolates from a hospital system in Pennsylvania over a 3-year period. All isolates were evaluated for colistin resistance using standard MIC testing by both agar dilution and broth microdilution, as well as genospecies identification and lipid A profiling using MS analyses. Overall, an excellent correlation between colistin susceptibility and resistance, determined by MIC testing, and the presence of a lipid A modification, determined by MS, was observed with a sensitivity of 92.9% and a specificity of 94.0%. Additionally, glycolipid profiling was able to differentiate A. baumannii complex organisms based on their membrane lipids. With the growth of MS use in clinical laboratories, a reliable MS-based glycolipid phenotyping method that identifies colistin resistance in A. baumannii complex clinical isolates, as well as other Gram-negative organisms, represents an alternative or complementary approach to existing diagnostics.
AB - Acinetobacter baumannii is a prevalent nosocomial pathogen with a high incidence of multidrug resistance. Treatment of infections due to this organism with colistin, a last-resort antibiotic of the polymyxin class, can result in the emergence of colistin-resistant strains. Colistin resistance primarily occurs via modifications of the terminal phosphate moieties of lipopolysaccharide-derived lipid A, which reduces overall membrane electronegativity. These modifications are readily identified by mass spectrometry (MS). In this study, we prospectively collected Acinetobacter baumannii complex clinical isolates from a hospital system in Pennsylvania over a 3-year period. All isolates were evaluated for colistin resistance using standard MIC testing by both agar dilution and broth microdilution, as well as genospecies identification and lipid A profiling using MS analyses. Overall, an excellent correlation between colistin susceptibility and resistance, determined by MIC testing, and the presence of a lipid A modification, determined by MS, was observed with a sensitivity of 92.9% and a specificity of 94.0%. Additionally, glycolipid profiling was able to differentiate A. baumannii complex organisms based on their membrane lipids. With the growth of MS use in clinical laboratories, a reliable MS-based glycolipid phenotyping method that identifies colistin resistance in A. baumannii complex clinical isolates, as well as other Gram-negative organisms, represents an alternative or complementary approach to existing diagnostics.
KW - Acinetobacter
KW - Colistin
KW - Lipid A
KW - Mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=85062268664&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85062268664&partnerID=8YFLogxK
U2 - 10.1128/JCM.01100-18
DO - 10.1128/JCM.01100-18
M3 - Article
C2 - 30567747
AN - SCOPUS:85062268664
SN - 0095-1137
VL - 57
JO - Journal of clinical microbiology
JF - Journal of clinical microbiology
IS - 3
M1 - e01100-18
ER -