Mutational change of CTX-M-15 to CTX-M-127 resulting in mecillinam resistant Escherichia coli during pivmecillinam treatment of a patient
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Mutational change of CTX-M-15 to CTX-M-127 resulting in mecillinam resistant Escherichia coli during pivmecillinam treatment of a patient. / Nielsen, Karen Leth; Hansen, Katrine Hartung; Nielsen, Jesper Boye; Knudsen, Jenny Dahl; Schønning, Kristian; Frimodt-Møller, Niels; Hertz, Frederik Boëtius; Jansåker, Filip.
I: MicrobiologyOpen, Bind 8, Nr. 12, e941, 2019.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Mutational change of CTX-M-15 to CTX-M-127 resulting in mecillinam resistant Escherichia coli during pivmecillinam treatment of a patient
AU - Nielsen, Karen Leth
AU - Hansen, Katrine Hartung
AU - Nielsen, Jesper Boye
AU - Knudsen, Jenny Dahl
AU - Schønning, Kristian
AU - Frimodt-Møller, Niels
AU - Hertz, Frederik Boëtius
AU - Jansåker, Filip
PY - 2019
Y1 - 2019
N2 - Pivmecillinam (amdinocillin pivoxil) is the recommended first-choice antibiotic used to treat urinary tract infections (UTIs) in Denmark. The frequency of mutation to mecillinam (MEC) resistance is described as high in vitro; however, treatment of UTI has a good clinical response and prevalence of mecillinam resistance in Escherichia coli remains low despite many years of use. We describe occurrence of in vivo mecillinam resistance in a clinical isolate of ESBL-producing E. coli following pivmecillinam treatment. The identified phenotypic differences in the mecillinam resistant isolate compared with the original mecillinam susceptible isolate were a full-length LPS with O-antigen (O25), mecillinam resistance and a lower MIC for ceftazidime. Regarding genotype, the resistant isolate differed with a mutation in blaCTX-M-15 to blaCTX-M-127 , loss of a part of a plasmid and a genomic island, respectively, and insertion of a transposase in wbbL, causing the rough phenotype. The observed mecillinam resistance is expected to be caused by the mutation in blaCTX-M-15 with additional contribute from the serotype shift. We continue to recommend the use of pivmecillinam as first-line treatment for UTI.
AB - Pivmecillinam (amdinocillin pivoxil) is the recommended first-choice antibiotic used to treat urinary tract infections (UTIs) in Denmark. The frequency of mutation to mecillinam (MEC) resistance is described as high in vitro; however, treatment of UTI has a good clinical response and prevalence of mecillinam resistance in Escherichia coli remains low despite many years of use. We describe occurrence of in vivo mecillinam resistance in a clinical isolate of ESBL-producing E. coli following pivmecillinam treatment. The identified phenotypic differences in the mecillinam resistant isolate compared with the original mecillinam susceptible isolate were a full-length LPS with O-antigen (O25), mecillinam resistance and a lower MIC for ceftazidime. Regarding genotype, the resistant isolate differed with a mutation in blaCTX-M-15 to blaCTX-M-127 , loss of a part of a plasmid and a genomic island, respectively, and insertion of a transposase in wbbL, causing the rough phenotype. The observed mecillinam resistance is expected to be caused by the mutation in blaCTX-M-15 with additional contribute from the serotype shift. We continue to recommend the use of pivmecillinam as first-line treatment for UTI.
U2 - 10.1002/mbo3.941
DO - 10.1002/mbo3.941
M3 - Journal article
C2 - 31573735
VL - 8
JO - MicrobiologyOpen
JF - MicrobiologyOpen
SN - 2045-8827
IS - 12
M1 - e941
ER -
ID: 231595544