Salmonella London

Background: Salmonella enterica subsp. enterica serovar London (antigenic formula 3,{10}{15}:l,v:1,6) is a serovar of the O:3,10 (E₁) serogroup. Serovar London was first identified in Reading, UK, from a patient with a surname starting with "L." Since serovar Reading was already in use, this new strain was named London, derived from the patient's name. According to the European Food Safety Authority (EFSA) and European Centre for Disease Prevention and Control (ECDC), serovar London has entered the top 20 list of most frequent Salmonella serovars in Europe.

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

Genetic characteristics: In a nosocomial outbreak associated with serovar London, Yong et al. identified the CTX-M-14-type extended-spectrum β-lactamase-producing strains. All these outbreak strains were multidrug resistant (MDR), while the other London strains reported were susceptible to multiple antibiotics, including ampicillin, suggesting the susceptible clone retained the resistance. MDR serovar London carrying bla_NDM-1 located on an IncA/C2 plasmid was reported in Singapore. A Chinese study analyzed a total of 88 representative isolates from human and food sources in Zhejiang Province, China, during 2016–2021 and revealed that

Animal reservoir:

Geographical distribution: According to the metadata from NCBI PD, serovar London has been reported worldwide but mainly in US, China, and UK.

Human outbreaks:

Year	Location	Associated source	Number of cases
2004	South Korea	Nosocomial	3
2000	South Korea	Infant formula	31

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:

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Salmonella London