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Salmonella Cotham

Background: Salmonella enterica subsp. enterica serovar Cotham (antigenic formula 28:i:1,5) is a serovar of the O:28 (M) serogroup. S. 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. A recent outbreak in the US was associated with S. Cotham, the outbreak investigation started in January 2014. To date (April, 2014), 132 cases have been reported and reptiles were found to be the source of this outbreak. In addition to this outbreak, S. Cotham was also reported in reptiles in Taiwan. 

NCBI PD link for serovar Cotham: https://www.ncbi.nlm.nih.gov/pathogens/isolates/#(taxgroup_name:%22Salmonella%20enterica%22)%20AND%20computed_types:(%22serotype=Cotham%22)

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 Animal reservoir: S. Cotham appears to be adapted to reptiles⁵.

Geographical distribution: This serovar is very rare, only two reports have been conducted, one in the US of an outbreak linked to reptiles and one report in Taiwan.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 outbreaks: Currently only two outbreaks Outbreaks: Currently only one outbreak had been reported, which started in February 2012. At April 2014 a total of 132 cases have been reported. In the outbreak 31 states in the US have been involved., and 2024, respectively. 

Relevant links:

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.

Relevant links:

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC10562597/
2. https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2025.1547190/full
3. https      http://www.cdc.gov/media/releases/2014/a0424-dragon-salmonella.html      http://vdi.sagepub.com/content/22/1/44.fullsalmonella/outbreaks/cotham-06-24/investigation.html?CDC_AAref_Val=https://www.cdc.gov/salmonella/cotham-06-24/details.html
4. https://archive.cdc.gov/www_cdc_gov/salmonella/cotham-04-14/index.html#:~:text=On%20January%2022%2C%202014%2C%20CDC,reporting%20exposure%20to%20pet%20reptiles.
5. https://doi.org/10.3201/eid3110.241803