S. Cotham¶

At a Glance


Antigenic Formula	`28:i:1,5`
Serogroup	O:28 (M)
NCBI Pathogen Detection	View isolates

Background Information¶

Salmonella enterica subsp. enterica serovar Cotham (antigenic formula 28:i:1,5) is a serovar of the O:28 (M) serogroup. Serovar Cotham is a very rare serovar; for example, this serovar was found to represent a very scarce percentage (0.01%) of all salmonellosis cases in the US since the 1960s.

Genetic Characteristics¶

Serovar Cotham has been found to be monophyletic. The NARMS laboratory at the CDC has analyzed Salmonella Cotham isolates obtained from 12 individuals infected with the 2014 outbreak strain. Among these, one isolate (8%) exhibited MDR, while the remaining 11 isolates (92%) were pansusceptible. The MDR isolate demonstrated resistance to the following antibiotics: amoxicillin/clavulanic acid, ampicillin, cefoxitin, ceftiofur, ceftriaxone, chloramphenicol, gentamicin, streptomycin, sulfisoxazole, and tetracycline. Additionally, it displayed intermediate susceptibility (neither fully resistant nor fully susceptible) to ciprofloxacin.

Animal Reservoir¶

Serovar Cotham appears to be adapted to reptiles⁵.

Geographical Distribution¶

This serovar is very rare, it has been mainly reported in Canada⁵, the US, but has also been found in Australia, Taiwan, Gambia, Nigeria, and parts of Europe, such as the UK and Ireland.

Human/Animal Outbreaks¶

Currently only two outbreaks had been reported, which started in 2012, and 2024, respectively.

Year	Location	Associated source	Number of cases
2024	US: multistate	Pet bearded dragons	26
2014	US: multistate	Pet bearded dragons¹	166

¹ Both serovar Cotham and Kisarawe were found.

Border Rejections¶

There have been no recent border rejections linked to this serovar.

Recalls¶

There have been no recent recalls linked to this serovar.