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Extended-Spectrum β-Lactamases in Human Isolates of Multidrug-Resistant Non-typhoidal Salmonella enterica
Anahit M Sedrakyan1, Zhanna A Ktsoyan1, Karine A Arakelova1
1Institute of Molecular Biology, National Academy of Sciences of RA, Yerevan, Armenia.
Abstract:
A total of 291 non-duplicate isolates of non-typhoidal Salmonella (NTS) were collected from the fecal samples of patients with salmonellosis in Armenia and Georgia during 1996-2016. The isolates were tested for resistance to antimicrobials, including extended-spectrum β-lactamases (ESBL). The high prevalence of multidrug-resistance (MDR) and ESBL-producer phenotypes was detected among Salmonella enterica subsp. enterica serovar Typhimurium (S. Typhimurium) isolates collected from patients in Armenia between 1996 and 2016. A total of 36 MDR NTS isolates were subjected to whole genome sequencing (WGS) to determine the genetic background of antimicrobial resistance (AMR) and mobile genetic elements. All ESBL-producing S. Typhimurium isolates belonged to the same sequence type (ST328). The ESBL-producer phenotype was associated with plasmid-encoded CTX-M-5 production. A range of other plasmids was associated with resistance to other antimicrobials, including the MDR phenotype.
Insights
Multidrug-resistant non-typhoidal Salmonella (NTS) strains, particularly Salmonella Typhimurium, show high prevalence in Armenia. Whole genome sequencing revealed plasmid-encoded resistance genes, including CTX-M-5, contributing to antimicrobial resistance (AMR) and multidrug-resistance (MDR) phenotypes.
Area of Science:
- Microbiology
- Genomics
- Public Health
Background:
- Non-typhoidal Salmonella (NTS) infections pose a significant public health challenge.
- Antimicrobial resistance (AMR) in NTS is a growing concern, particularly in regions like Armenia and Georgia.
- Extended-spectrum β-lactamase (ESBL) production is a key mechanism of resistance in Gram-negative bacteria.
Purpose of the Study:
- To investigate the prevalence of antimicrobial resistance (AMR) and multidrug-resistance (MDR) in non-typhoidal Salmonella (NTS) isolates from Armenia and Georgia.
- To determine the genetic basis of AMR and identify mobile genetic elements in MDR NTS isolates using whole genome sequencing (WGS).
- To characterize ESBL-producing Salmonella Typhimurium isolates, including their sequence type and resistance mechanisms.
Main Methods:
- Collection and antimicrobial susceptibility testing of 291 NTS isolates from patients in Armenia and Georgia (1996-2016).
- Phenotypic detection of extended-spectrum β-lactamase (ESBL) production.
- Whole genome sequencing (WGS) of 36 multidrug-resistant (MDR) NTS isolates.
- Bioinformatic analysis to identify AMR genes, mobile genetic elements, and sequence types.
Main Results:
- High prevalence of multidrug-resistance (MDR) and ESBL-producer phenotypes was observed among Salmonella Typhimurium isolates from Armenia.
- All ESBL-producing Salmonella Typhimurium isolates belonged to sequence type ST328.
- Plasmid-encoded CTX-M-5 production was associated with the ESBL-producer phenotype.
- Various other plasmids were identified, contributing to the MDR phenotype.
Conclusions:
- Salmonella Typhimurium in Armenia exhibits a high prevalence of multidrug-resistance (MDR) and ESBL production.
- Plasmid-mediated resistance, particularly CTX-M-5, plays a crucial role in the emergence of MDR and ESBL-producing Salmonella Typhimurium.
- WGS is a valuable tool for understanding the genetic epidemiology of AMR in Salmonella.
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