Detection and Molecular Characterization of Escherichia coli CTX-M-15 and Klebsiella pneumoniae SHV-12 β-Lactamases from Bovine Mastitis Isolates in the United Kingdom

Abstract

c Recent reports raised concerns about the role that farm stock may play in the dissemination of extended-spectrum ␤-lactamase (ESBL)-producing bacteria. This study characterized the ESBLs in two Escherichia coli and three Klebsiella pneumoniae subsp. pneumoniae isolates from cases of clinical bovine mastitis in the United Kingdom. Bacterial culture and sensitivity testing of bovine mastitic milk samples identified Gram-negative cefpodoxime-resistant isolates, which were assessed for their ESBL phenotypes. Conjugation experiments and PCR-based replicon typing (PBRT) were used for characterization of transferable plasmids. E. coli isolates belonged to sequence type 88 (ST88; determined by multilocus sequence typing) and carried bla CTX-M-15 and bla TEM-1 , while K. pneumoniae subsp. pneumoniae isolates carried bla SHV-12 and bla TEM-1 . Conjugation experiments demonstrated that bla CTX-M-15 and bla TEM-1 were carried on a conjugative plasmid in E. coli, and PBRT identified this to be an IncI1 plasmid. The resistance genes were nontransferable in K. pneumoniae subsp. pneumoniae isolates. Moreover, in the E. coli isolates, an association of ISEcp1 and IS26 with bla CTX-M-15 was found where the IS26 element was inserted upstream of both ISEcp1 and the bla CTX-M promoter, a genetic arrangement highly similar to that described in some United Kingdom human isolates. We report the first cases in Europe of bovine mastitis due to E. coli CTX-M-15 and also of bovine mastitis due to K. pneumoniae subsp. pneumoniae SHV-12 ␤-lactamases in the United Kingdom. We also describe the genetic environment of bla CTX-M-15 and highlight the role that IncI1 plasmids may play in the spread and dissemination of ESBL genes, which have been described in both human and cattle isolates.

Tasa de incidencia de mastitis clínica y susceptibilidad antibiótica de patógenos productores de mastitis en ganado lechero del norte de Antioquia, Colombia

“…La producción de BLEE por bacterias reduce la eficacia de un amplio rango de antibióticos betalactámicos como cafalosporinas de tercera generación y monobactámicos (38), y se ha documentado que los animales productores de alimentos son importantes reservorios de Enterobacteriaceae productora de BLEE (39). E. coli multiresistente ha sido aislada de leche bovina en varios estudios previos (40)(41)(42)(43)(44)(45)(46), lo que demanda muchos más estudios para establecer la importancia de este fenómeno en el ámbito nacional.…”

Nosocomial infection and its molecular mechanisms of antibiotic resistance

“…More than fifty members of the SHV family recently have been identified through unique combinations of amino acid replacements (24). The SHV family recently has been shown in surveys of resistant strains in Europe and America (25,26). SHV-5 and SHV-12 are prevalent among the members of the SHV family (27).…”

Occurrence and characterisation of MRSA and extended-spectrum ß-lactamases producing Escherichia coli isolated from mastitic cows’ milk

“…Timofte et al (26) isolated E. coli with blaCTX-M-15 and blaTEM-1 genes from the cases of bovine mastitis in United Kingdom. Ohnishi et al (20) described 65 ESBL-producing Enterobacteriaceae (E. coli and Klebsiella pneumoniae with blaCTX-M) isolated from 258 880 samples of mastitic milk samples.…”