Molecular characterization of florfenicol and oxazolidinone resistance in Enterococcus isolates from animals in China
Florfenicol is widely used for the treatment of bacterial infections in domestic animals. The aim of this study was to analyze the molecular mechanisms of florfenicol and oxazolidinone resistance in Enterococcus isolates from anal feces of domestic animals. The minimum inhibitory concentration (MIC)...
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Published in | Frontiers in microbiology Vol. 13; p. 811692 |
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Main Authors | , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Frontiers Media S.A
26.07.2022
|
Subjects | |
Online Access | Get full text |
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Summary: | Florfenicol is widely used for the treatment of bacterial infections in domestic animals. The aim of this study was to analyze the molecular mechanisms of florfenicol and oxazolidinone resistance in
Enterococcus
isolates from anal feces of domestic animals. The minimum inhibitory concentration (MIC) levels were determined by the agar dilution method. Polymerase chain reaction (PCR) was performed to analyze the distribution of the resistance genes. Whole-genome sequencing and comparative plasmid analysis was conducted to analyze the resistance gene environment. A total of 351 non-duplicated enteric strains were obtained. Among these isolates, 22
Enterococcus
isolates, including 19
Enterococcus. faecium
and 3
Enterococcus. faecalis
, were further studied. 31 florfenicol resistance genes (13
fexA
, 3
fexB
, 12
optrA,
and 3
poxtA
genes) were identified in 15 of the 19
E. faecium
isolates, and no florfenicol or oxazolidinone resistance genes were identified in 3
E. faecalis
isolates. Whole-genome sequencing of
E. faecium
P47, which had all four florfenicol and oxazolidinone resistance genes and high MIC levels for both florfenicol (256 mg/L) and linezolid (8 mg/L), revealed that it contained a chromosome and 3 plasmids (pP47-27, pP47-61, and pP47-180). The four florfenicol and oxazolidinone resistance genes were all related to the insertion sequences IS
1216
and located on two smaller plasmids. The genes
fexB
and
poxtA
encoded in pP47-27, while
fexA
and
optrA
encoded in the conjugative plasmid pP47-61. Comparative analysis of homologous plasmids revealed that the sequences with high identities were plasmid sequences from various
Enterococcus
species except for the Tn
6349
sequence from a
Staphylococcus aureus
chromosome (MH746818.1). The current study revealed that florfenicol and oxazolidinone resistance genes (
fexA
,
fexB
,
poxtA,
and
optrA
) were widely distributed in
Enterococcus
isolates from animal in China. The mobile genetic elements, including the insertion sequences and conjugative plasmid, played an important role in the horizontal transfer of florfenicol and oxazolidinone resistance. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 Edited by: Kristina Kadlec, Independent researcher, Wunstorf, Germany These authors have contributed equally to this work Reviewed by: Patricia Alba, Experimental Zooprophylactic Institute of the Lazio and Tuscany Regions (IZSLT), Italy; Ilana L. B. C. Camargo, University of São Paulo, Brazil This article was submitted to Antimicrobials, Resistance and Chemotherapy, a section of the journal Frontiers in Microbiology |
ISSN: | 1664-302X 1664-302X |
DOI: | 10.3389/fmicb.2022.811692 |