Food Protection Trends - March/April 2025 - 109

TABLE 3. Overrepresentation of specific serovars among cattle, chicken, and turkey in
NCBI versus FSIS databasesa
Cattle
Salmonella serovar
Adelaide
Agona
Anatum
Cerro
Derby
Dublin
Enteritidis
Hadar
Heidelberg
I 4,[5],12:i:−
Infantis
Javiana
Johannesburg
Kentucky
Montevideo
Muenchen
Muenster
Newport
Reading
Schwarzengrund
Typhimurium
a
OR
0.33
0.776
0.841
2.43
0.228
3.63
1.49
0.495
10.5
1.09
0.5
Inf
0.0752
0.624
0.432
0.337
0.453
1.07
0.358
0.628
1.27
P-value
0.207
0.192
0.0921
1.30E-11
7.81E-04
6.40E-31
0.399
0.404
1.96E-08
0.410
2.70E-03
0.447
2.78E-05
0.0253
6.12E-17
1.46E-11
8.01E-05
0.41
0.0226
0.171
0.0574
OR
Inf
2.84
1.96
3.74
Inf
Inf
0.605
3.12
1.71
1.04
0.852
Inf
0.348
0.886
1.16
47.2
4.80
11.0
19.3
0.272
1.67
Chicken
P-value
0.277
8.54E-03
0.0381
6.84E-03
5.57E-40
0.0765
1.13E-25
2.33E-06
2.63E-09
0.451
5.77E-04
0.0212
4.75E-05
1.37E-03
0.289
6.55E-123
1.57E-03
2.45E-19
4.66E-10
1.43E-41
4.21E-19
OR
-
0.503
0.676
7.84
Inf
0.693
0.102
2.15
1.18
0.579
0.729
3.21
1.24
2.30
0.797
0.795
0.833
1.32
Turkey
P-value
-
6.34E-05
0.0622
0.327
0.0108
0.673
0.306
0.447
2.93E-04
0.177
4.49E-04
0.527
0.327
2.55E-03
0.280
3.02E-09
1.29E-04
0.307
5.11E-03
0.120
0.0414
On the basis of the results of the Fisher exact test, if P < 0.05. An OR > 2 indicated overrepresentation in the NCBI database, while an
OR < 0.5 indicated overrepresentation in the FSIS data set for that serovar and animal source. If P > 0.05, the result was recorded as " -. "
quently identified serovar among both NCBI and FSIS data.
In the FSIS data set, numbers of Salmonella Enteritidis and
Salmonella Kentucky isolates followed similar patterns until
2020. Both isolate numbers of serovars increased between
2015 and 2016 (a 1-year increase of 86 and 61%, respectively),
increased further in 2017 (a 1-year increase of 11 and
4%, respectively), and decreased in 2018 (a decrease of 8 and
14%, respectively) and 2019 (a decrease of 6 and 5%, respectively).
From 2019 to 2020, numbers of Salmonella Kentucky
isolates in the FSIS data increased by 11%, while numbers
of Salmonella Enteritidis isolates decreased by 11%. Notably,
numbers of Salmonella Infantis isolates steadily increased by
826% from 2015 to 2020, and Salmonella Infantis became the
second most frequently isolated serovar in chicken in 2020.
In the NCBI data set, numbers of isolates of Salmonella
serovars Infantis, Typhimurium, and Kentucky followed
109 Food Protection Trends March/April
similar patterns in that all three increased between 2016 and
2017 (400, 170, and 76% respectively), increased between
2018 and 2019 (449, 128, and 343%, respectively), and then
decreased from 2019 to 2020 (−82, −78, and −85%, respectively)
(Fig. 2B and Table S4). Salmonella Infantis was the
least frequently identified serovar among the top 10 serovars
in 2015 but became the second most frequently identified
serovar in 2020, as also observed in the FSIS data discussed
in the previous paragraph. Numbers of Salmonella Enteritidis
isolates remained similar between 2015 and 2018 but increased
by 88% between 2018 and 2019. Notably, for nearly
all serovars, the total numbers of isolates decreased in 2020
and fell to between 0 and 100 isolates in 2020 (most likely a
consequence of the coronavirus disease 2019 pandemic).
A comparison of counts of chicken serovars between NCBI
and FSIS data sets found that seven and two serovars were
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