Background
Colistin and carbapenem-resistant bacteria have emerged and become a serious public health concern, but their epidemiological data is still limited.
Objectives
This study examined colistin and carbapenem resistance in
Escherichia coli
and
Salmonella
from pigs, pig carcasses, and pork in Thailand, Lao PDR, and Cambodia border provinces.
Methods
The phenotypic and genotypic resistance to colistin and meropenem was determined in
E. coli
and
Salmonella
obtained from pigs, pig carcasses, and pork (n = 1,619). A conjugative experiment was performed in all isolates carrying the
mcr
gene (s) (n = 68). The plasmid replicon type was determined in the isolates carrying a conjugative plasmid with
mcr
by PCR-based replicon typing (n = 7). The genetic relatedness of
mcr
-positive
Salmonella
(n = 11) was investigated by multi-locus sequence typing.
Results
Colistin resistance was more common in
E. coli
(8%) than
Salmonella
(1%). The highest resistance rate was found in
E. coli
(17.8%) and
Salmonella
(1.7%) from Cambodia. Colistin-resistance genes,
mcr-1
,
mcr-3
, and
mcr-5
, were identified, of which
mcr-1
and
mcr-3
were predominant in
E. coli
(5.8%) and
Salmonella
(1.7%), respectively. The
mcr-5
gene was observed in
E. coli
from pork in Cambodia. Two colistin-susceptible pig isolates from Thailand carried both
mcr-1
and
mcr-3
. Seven
E. coli
and
Salmonella
isolates contained
mcr-1
or
mcr-3
associated with the IncF and IncI plasmids. The
mcr
-positive
Salmonella
from Thailand and Cambodia were categorized into two clusters with 94%–97% similarity. None of these clusters was meropenem resistant.
Conclusions
Colistin-resistant
E. coli
and
Salmonella
were distributed in pigs, pig carcasses, and pork in the border areas. Undivided-One Health collaboration is needed to address the issue.
Background and Aim: The genetic relationship among serotypes of Salmonella enterica from food animals, food of animal origin, and human is of interest as the data could provide an important clue for the source of human infection. This study aimed to determine the genetic relatedness of S. enterica from pig production and human in Thailand-Laos border provinces.
Materials and Methods: A total of 195 S. enterica serotypes isolated from pig and pork (n=178) and human (n=17) including four serotypes (Typhimurium, Rissen, Derby, and Stanley) were randomly selected to examine their genetic relatedness using highly conserved sequence of three genes (fim A, man B, and mdh).
Results: The results showed that 195 Salmonella isolates of four different serotypes were grouped into five different clusters, and members of the same Salmonella serotypes were found in the same cluster. Salmonella isolated from pig production and human in Thailand-Laos border provinces represented overlapping population and revealed a high degree of similarity, indicating close genetic relationship among the isolates.
Conclusion: The results support that the determination of Salmonella serotyping combined with analysis of phylogenetic tree can be used track the clonal evolution and genetic diversity of Salmonella serotypes in different host species.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.