Antimicrobial resistance of Salmonella enterica Typhimurium DT104 isolates and investigation of strains with transferable apramycin resistance

Abstract

An examination of salmonella isolates collected by the Scottish Agricultural College Veterinary Services Division from April 1994 to May 1995 was conducted to determine the extent to which Salmonella enterica serotype Typhimurium phage type 104 (DT104) occurred and to investigate the antimicrobial resistance patterns of isolates. Typhimurium DT104 was the predominant salmonella and was isolated from nine species of animal. All isolates of this phage type possessed resistance to at least one antimicrobial and 98% of the isolates were resistant to multiple antimicrobials with R-type ACTSp the predominant resistance pattern. Various other resistance patterns were identified and transferable resistance to the veterinary aminoglycoside antimicrobial apramycin was demonstrated in three strains. A retrospective study for gentamicin resistance in isolates from the Scottish Salmonella Reference Laboratory collection revealed a human isolate of Typhimurium DT104 resistant to gentamicin but sensitive to apramycin and a bovine isolate with apramycin and gentamicin resistance.

Analysis of Salmonella enterica serotype Typhimurium by phage typing, antimicrobial susceptibility and pulsed-field gel electrophoresis

“…Although, in developed countries, only a single phage type has often been associated with outbreaks of multiresistant Typhimurium infection in both man and animals [4,6,28], the findings from the present study did not indicate a significant predominance of any one phage type. Also, there was no significant association between any one phage type and the multiresistance phenotype.…”

Emergence of Salmonella epidemics: The problems related to Salmonella enterica serotyp Enteritidis and multiple antibiotic resistance in other major serotypes

“…Additional resistance to trimethoprim (Tm), occasionally seen among S. Typhimurium DT104 strains, may be encoded by a non-conjugative but mobilisable plasmid of approximately 4.6 MDa which also encodes resistance to Su [139]. Transferable apramycin resistance has also been described in some DT104 strains [90].…”

Molecular characterization, spread and evolution of multidrug resistance in Salmonella enterica Typhimurium DT104

“…Additional resistance to trimethoprim, occasionally seen among DT104 strains, may be encoded by a non-conjugative but mobilizable plasmid of approximately 4.6 MDa which also encodes resistance to sulfonamides [50]. Transferable apramycin resistance has also been described in some multidrug-resistant DT104 strains [31]. This paper reviews new developments in the characterization of chromosomal DT104 antibiotic resistance genes, their spread among other S. enterica Typhimurium phage types and other S. enterica serovars, the development of specific detection methods, and the evolution in multidrug resistance with regard to the emergence of quinolone resistance.…”