Antibiotic resistance and virulence factors in clinical Salmonella enterica isolates

作者：de Toro Maria; Seral Cristina; Rojo Bezares Beatriz; Torres Carmen; Javier Castillo F; Saenz Yolanda^*

来源：Enfermedades Infecciosas y Microbiologia Clinica, 2014, 32(1): 4-10.

DOI：10.1016/j.eimc.2013.03.006

• Ampicillin-resistance
• bla(PSE-1)
• bla(OXA-1)
• ACSSuT phenotype
• Integrons
• Salmonella Genomic Island type 1
• Pulsed-field gel electrophoresis

Introduction: The increase of Salmonella enterica isolates multi-resistant to different antibiotics, including beta-lactams and fluoroquinolones, is a problem of clinical importance. The dissemination of Salmonella Typhimurium resistant to ampicillin (AMP)-chloramphenicol (CHL)-streptomycin (STR)-sulphonamides and (SUL)-tetracycline (TET), that harbour the Salmonella Genomic Island type 1 (SGI1), and the acquisition of transferable genetic material have favoured the multi-resistance in this genus. %26lt;br%26gt;Methods: A total of 114 clinical S. enterica isolates were studied (period 2009-2010). The susceptibility to 20 antibiotics was determined by disc diffusion and microdilution. The antimicrobial resistance mechanisms and the integrons were analysed by PCR, and sequencing in the AMP(R) isolates. In all the bla(PSE-1)-positive isolates, the clonal relationship was determined by PFGE, as well as the presence of SGI1 and 29 virulence genes by PCR. %26lt;br%26gt;Results: Eighteen different serotypes were found among the 114 isolates studied, Typhimurium (61%) and Enteritidis (16%) being the most prevalent. High percentages of resistance to SUL (68%), TET (58%), AMP (55%) and STR (46%) were observed. The great majority (92%) of 63 AMP(R) isolates were multi-resistant, with the AMP-STR-TET-SUL phenotype (19 isolates) being the most frequent one and associated with the bla(TEM-1b) + strA-strB + tet(B)+ sul2 genotype. Class 1 integrons (7 different structures) were observed in 48% AMP(R) isolates, highlighting the bla(OXA-1) + aadA1 structure (8 isolates), one empty integron and non-classical integrons (5 isolates). The bla(PSE-1) gene was detected inside the classical SGI1 structure in 13 clonally-related isolates that showed the same virulence profile. %26lt;br%26gt;Conclusions: The high percentage of multi-resistant S. enterica isolates, especially associated to S. Typhimurium, to the AMP, STR, TET and SUL phenotype, and to the bla(TEM-1b) + strA-strB + tet(B)+ sul2 genotype, shows an important risk of possible failures in the treatment of serious infections caused by this serotype.

• 出版日期2014-1