Emergence of extended-spectrum  -lactamases and AmpC-type  -lactamases in human Salmonella isolated in Spain from 2001 to 2005

• Published in: Journal of antimicrobial chemotherapy 2009-12, Vol.64 (6), p.1181-1186
• Main Authors: Gonzalez-Sanz, R., Herrera-Leon, S., de la Fuente, M., Arroyo, M., Echeita, M. A.
• Format: Article
• Language: English
• Subjects: Antibiotics; Drug resistance; E coli; Genes; Genotype & phenotype; Public health; Salmonella
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dkp361

To study the resistance to third-generation cephalosporins in Salmonella strains isolated from humans in a 5 year period in Spain, and to identify the responsible genes and their dissemination. Twenty-seven isolates were analysed by PCR and sequencing to identify the genes responsible for the β-lactamase resistance phenotypes. The transferability of the phenotypes was tested by conjugation to Escherichia coli K12J53, plasmid detection with S1-PFGE, hybridization and PCRs of the transconjugants. The genetic relationship was determined by PFGE. We found bla... and bla... in Salmonella Virchow PT19. bla... was detected in Salmonella (IV) 44:...:-, Salmonella Enteritidis PT6a, Salmonella Typhimurium DT193 and Salmonella Typhimurium DT104B. bla... was found in Salmonella Litchfield. blaCTX-M-15 and bla... were found in Salmonella Enteritidis PT1. bla... was found in Salmonella Blockley, Salmonella Hadar PT2, Salmonella Enteritidis PT21, Salmonella Enteritidis PT1 and Salmonella Bredeney. bla... was found in Salmonella Livingstone. bla... was detected in Salmonella Bredeney, Salmonella Newport, Salmonella Enteritidis PT5b and Salmonella Heidelberg. bla... was detected for the first time in Spain in Salmonella Newport. One strain of Salmonella Senftenberg harboured two extended-spectrum β-lactamases, bla... and bla... We have found a large variety of β-lactamase families as well as several members of major relevance, such as CTX-M-15, CTX-M- 32, CMY-2 and DHA-1. XbaI-PFGE, conjugation assays and S1-PFGE hybridization showed that all these β-lactamases were mediated by plasmids. This study demonstrates the emergence of a public health risk related to resistance to β- lactams in Salmonella. The resistance trends need to be monitored carefully. (ProQuest: ... denotes formulae/symbols omitted.)