S. Indiana¶

At a Glance


Antigenic Formula	`1,4,12:z:1,7`
Serogroup	O:4 (B)
NCBI Pathogen Detection	View isolates

Background Information¶

Salmonella enterica subsp. enterica serovar Indiana (antigenic formula 1,4,12:z:1,7) is a serovar of the O:4 (B) serogroup. Serovar Indiana was first isolated from a 9-month-old child in 1955 in Indiana, US. Infection of this serovar can result in abortion in ewes. In recent years, serovar Indiana has emerged and expanded rapidly in China, frequently identified in patients experiencing diarrhea.

Genetic Characteristics¶

Serovar Indiana has been found to be polyphyletic with one lineage identified and one stand-alone singleton that does not cluster with any other Salmonella Indiana isolates. Luque et al. analyzed 17 Indiana strains isolated from the ewes and wild birds and revealed that 11 (64.7%) were resistant to nalidixic acid (R-Nx), while 6 (35.3%) were sensitive (S-Nx). Sequencing of the gyrA gene identified specific mutations in the R-Nx strains: a substitution of glycine to cysteine at position 81 (Gly81→Cys) was found in 10 strains isolated from wild birds and ovine fetuses, and a substitution of aspartic acid to tyrosine at position 87 (Asp87→Tyr) was identified in one strain isolated from ewe feces. Serovar Indiana was commonly found in raw chicken from the Henan province in China, which have been reported to be resistant to ciprofloxacin, with frequent co-resistance to cefotaxime. A Chinese studyindicated that serovar Indiana ST17 is an emerging multidrug-resistant (MDR) superclone found in chickens. ST17 carries a novel cluster of resistance genes, including bla_CTX-M, bla_OXA-1-like, and/or bla_TEM-1-like. Zhang et al.found that ST17 isolates were distributed into four clades (I, II, III and IV), which was likely linked to international clonal dissemination. Hu et al. investigated a total of 224 CIP-CTX co-resistant Indiana isolates collected from retail chicken samples in China and found the most prevalent amino acid substitutions observed were in GyrA (S83F and D87N/G) and ParC (T57S and S80R). Additionally, the plasmid-mediated quinolone resistance (PMQR) genes oqxA, oqxB, and aac(6′)-Ib-cr were frequently identified as key contributors to quinolone resistance.

Animal reservoir: The most common reservoir for serovar Indiana is retail chicken, but it was also found incattle, turkey, duck, sheep and swine.

Geographical Distribution¶

Serovar Indiana has been reported worldwide and has extremely expanded in China.

Human/Animal Outbreaks¶

Year	Location	Associated food	Number of cases
2024	US: multistate	Backyard poultry¹	470
2015	US: multistate	Backyard poultry	68
1986	UK	Not identified	5 infants + 7 adults
1981	Netherlands	Salad base	Estimated 600-700
1967	US: PA	Unpasteurized cup cheese	NA

¹ Multiple serovars, including Salmonella Altona, Cerro, Enteritidis, Indiana, Infantis, Johannesburg, Mbandanka, and Typhimurium, were linked to this outbreak. The case number represents the total number of cases associated with the outbreak and does not specifically indicate the number of people infected by Salmonella Indiana.

Border Rejections¶

Year	Exporting country	Importing country	Associated source	Product category
2021	Poland	Italy	Carne di taccino congelata- frozen turkey meat¹	Meat and meat products (other than poultry)

¹ Serovar Indiana were found in 1 out of 5 samples /25g.

Recalls¶

There have been no recent recalls linked to this serovar.