340  ◾  Fundamental Food Microbiology
concern is the MDR Sal. enterica ser. Typhimurium definitive phage type (DT) 104. The strains
are resistant to several antibiotics, including ampicillin, chloramphenicol, streptomycin, spectinomycin, sulfonamides, florfenicol, and tetracycline. DT104 has also been reported to be resistant to
nalidixic acid and ciprofloxacin. In addition, an emerging strain, DT204, resistant to eight or nine
antibiotics, is also a concern. It is suspected that antibiotic resistance may be transferred among
strains or serovars by different methods of genetic recombinations, especially under antibiotic
table 26.2 top twenty Salmonella enterica
Serotypes that Are Responsible for Majority of
outbreaks in Recent Years a , 2009
Rank
Serotype
Percent
1
Enteritidis
17.5
2
Typhimurium
15.0
3
Newport
9.3
4
Javiana
4.9
5
Heidelberg
3.5
6
Montevideo
3.1
7
I 4,[5],12:i:2.4
8
Oranienburg
2.2
9
Saintpaul
2.1
10
Muenchen
2.0
11
Braenderup
1.8
12
Infantis
1.6
13
Thompson
1.2
14
Mississippi
1.1
15
Paratyphi B
1.1
16
Typhi
1.1
17
Agona
1.0
18
Schwarzengrund
0.9
19
Bareilly
0.7
20
Hadar
0.7
Others
27.2
Total
100
a An overview of National Salmonella Surveillance is available online at http://www.cdc.gov/nationalsurveillance/
PDFs/NationalSalmSurveillOverview_508.pdf.