Ruiz-Ripa L, Feßler AT, Hanke D, Sanz S, Olarte C, Eichhorn I, Schwarz S, Torres C. Detection of poxtA- and optrA-carrying E. faecium isolates in air samples of a Spanish swine farm.
J Glob Antimicrob Resist 2019;
22:28-31. [PMID:
31884049 DOI:
10.1016/j.jgar.2019.12.012]
[Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Accepted: 12/16/2019] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVE
Two linezolid-resistant Enterococcus faecium isolates, C10004 and C10009, were recovered from air samples of a Spanish swine farm and comprehensively characterized.
METHODS
Detection of linezolid resistance mechanisms (mutations and acquisition of resistance genes) was performed by PCR/sequencing. Isolates were characterized by multilocus sequence typing (MLST), antimicrobial susceptibility testing, detection of antimicrobial resistance and virulence genes, and analysis of the genetic environment of the linezolid resistance genes. The characterization of isolate C10009 was performed by Whole-Genome-Sequencing and of isolate C10004 by PCR and amplicon sequencing, where applicable. Conjugation experiments to assess the transferability of the optrA and poxtA genes implicated in linezolid resistance were performed.
RESULTS
The linezolid-resistant E. faecium isolates C10004 and C10009, assigned to ST128 and ST437, respectively, harbored the optrA and poxtA genes. Neither mutations in the 23S rRNA nor in the genes for the ribosomal proteins L3, L4 and L22 were detected. C10004 and C10009 carried fourteen and thirteen antimicrobial resistance genes, respectively. The sequence alignment indicated that the genetic environment of the poxtA gene was identical in both isolates, with a downstream-located fexB gene. The poxtA gene was transferred by conjugation together with the fexB gene, and also with tet(M) and tet(L) in the case of isolate C10004. The optrA gene could not be transferred.
CONCLUSIONS
This is the first report of the poxtA gene in Spain. The presence of poxtA- and optrA-carrying E. faecium isolates in air samples represents a public health concern, indicating an involvement of swine farms in the spread of linezolid-resistant bacteria.
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