Epidemiological studies of human and animal Salmonella Typhimurium DT104 and DT104b isolates in Ireland

Abstract

A total of 122 human and animal Salmonella Typhimurium DT104 isolates and 6 epidemiologically related DT104b isolates from human and animal products were analysed by pulsed-field gel electrophoresis (PFGE). Genomic DNA was subjected to macrorestriction with three enzymes, SpeI, SfiI and XbaI. A total of 14 restriction fragment length polymorphism (RFLP) profiles were identified when the PFGE patterns from the three enzymes were combined. The majority of isolates (81.2%) exhibited the same RFLP profile. Six animal DT104 isolates, susceptible to enrofloxacin and resistant to naladixic acid, were identified from the antibiotic susceptibility test. Four of these isolates had a different PFGE profile from the common RFLP. In addition, 4 of the 6 isolates were geographically clustered in one region. It was concluded that there was one predominant strain of S. Typhimurium DT104 in Ireland and that the potential and selection pressures for emergence of fluoroquinolone-resistant isolates were present.

Molecular Characterization of Salmonella enterica Serovar Typhimurium Isolated from Human, Food, and Animal Sources in Malaysia

“…Currently, pulsed-field gel electrophoresis (PFGE) is considered the gold standard technique for molecular subtyping of Salmonella and has been widely used in Malaysian studies (2,3). However, the PFGE method has been less successful in discriminating between genetically homogeneous strains (13). The introduction of the multilocus variable number tandem repeat analysis (MLVA) method has addressed this problem (14,15).…”

Characterization of Salmonella enterica Serotype Typhimurium Isolates from Human, Food, and Animal Sources in the Republic of Ireland

“…Despite the importance of Salmonella serotype Typhimurium in causing salmonellosis in Ireland, there have been a limited number of epidemiological studies of this organism (5,6,9,15). This study has applied a combination of phenotypic and genotypic typing methods, including pulsed-field gel electrophoresis (PFGE), which has been recognized as a powerful tool and the "gold standard" of molecular typing methods (19,24), in the analysis of S. enterica serotype Typhimurium DT104 and DT104b from human, food, and animal sources over a 2-year period in the midwest region of Ireland.…”

Characterization ofSalmonella entericaSerovar Typhimurium and MonophasicSalmonellaSerovar 1,4,[5],12:i:- Isolates in Thailand

“…Identification and subtyping of MDR serovar Typhimurium is necessary for understanding and control of the associated infection (7,15). Even though phage typing is a good method for epidemiological surveillance of serovar Typhimurium, a phage typing laboratory is not available in many countries.…”

“…Salmonella enterica serovar Typhimurium phage types DT104 and U302 are considered zoonotic and life-threatening pathogens (1,15). These strains are commonly associated with multiple-drug-resistant (MDR) characteristics that are carried by genetic elements in chromosome (4,6,13,18).…”

“…Serovar Typhimurium is one of the common serovars found globally, including Thailand. However, serovar Typhimurium has not caused a critical outbreak in Thailand, and the incidence of these strains has not increased as in some countries (1,3,13,15).…”