TRENDS IN SALMONELLA ASSOCIATED WITH INVASIVE AND NON-INVASIVE INFECTIONS OVER A TEN-YEAR PERIOD IN THE GAMBIA, WEST AFRICA. SAFFIATOU DARBOE MRC Unit, The Gambia Date: 19th November, 2015

Conflict of interest: None x No, nothing to disclose Yes, please specify: Company Name Honoraria/ Expenses Consulting/ Advisory Board Funded Research Royalties/ Patent Stock Options Ownership/ Equity Position Employee Other (please specify) Medical Research Council Unit, The Gambia x Mphil student            Declaration

Background (1) Salmonella enterica infections are common cause of food-borne diseases worldwide usually with self limiting outcome. In resource limited settings however, they are a common cause of bacteraemia associated with high case fatality ratio and difficult to distinguish from other febrile illnesses. Culture and complex serological assays remains mainstay of laboratory diagnosis. Serovars are commonly clinically divided into two: Typhoidal – Causing enteric fever (Typhi, Paratyphi A, B and C) Human host restricted; transmission through faecal-oral route Non-typhoidal Salmonellae (NTS) – causing mainly gastroenteritis (Other serovars) Broad host range; zoonotic infections Complex scientific nomenclature , but ….2 species: bongori and enterica Sub species: enterica, salamae, arizonae, diarizonae, houtenae and indica. (over 2500 serovars

Background (2) In The Gambia, large data gaps exist in the epidemiology of diseases by S. enterica. NTS has been reported to be a more common cause of bacteraemia than S. Typhi. A strong association between Salmonella invasive disease and malaria is believed to exist. The association with other disease conditions and risks factors is yet to be fully studied in our setting. Surveillance of diseases is critical to determine regional epidemiology of serovars and emergence of multi-drug resistance.

Methods: study population and lab analysis Retrospective analysis of stored samples from various clinical specimens from 3 regions in the country: Western Region- Various Clinical samples from patients in MRC Fajara Lower River Region – Stool from children in Keneba Upper River Region – Stool samples from Global enteric multicentre (Gems) study Lab analysis: Culture and identification using routine media Serotyping Susceptibility testing

Aims Highlight the burden of Salmonella enterica infections in our setting; Antibiotic resistance Serotype distribution Age distribution Evaluate the impact of the two main clinical groups in terms of disease burden and invasiveness. Aim of the lab surveillance ………

Salmonella prevalence Fig 1 A. Prevalence in salmonella across the different was between 0.7 to 1.0%. B. Faecal asymtomatic carriage remained the same throughout the year as opposed to bacteramia incidence which was higher during the peak malaria transmission season. C. Asymtomatic carriage is high, in the Gems case control study no difference was found in the rates of infection in those with diarrhoea and those without. D. When seasonality is taken into account however, the peak time for cases was the malaria peak season and there was difference in the carriage.

Antibiotic resistance pattern Fig 2. Resistance to the common antibiotics seen, although incidence low up to 2014. Of particular significance is the recent 2015 data on usually resistance which was compared to the other years although numbers are small to conclude on anything yet.

Serogroup and serotype distribution Fig 3. Infection distribution by serovar Fig A. NTS causing more infection in both invasive and none invasive disease in our setting than typhi. However infection with Typhi is more associated with invasive disease. Fig B. The different groups mainly associated with invasive disease are groups B and D which as in fig C comprise S. typhimurium and Enteritidis and Typhi (groupD).

Age distribution ≤ 5years (%) ≥ 5 years (%) Total Blood 63 (59.4) 43 (40.6) 106 Stool 115 (93.5) 8 (6.5) 123 CSF 1 Urine 7 Asp/ Pus/Abs 2 6 8 181 64 245 Bactaeramia and gastroenteritis more common in the under 5 age bracket

Conclusion 1st data on trend and phenotypic characteristics of both NTS and typhoidal Salmonella roles in infection in The Gambia. NTS are the most common cause of both bacteraemia and gastroenteritis S. Typhimurium was the leading followed closely by S. Enteritidis. S. Typhi mainly caused invasive disease. Risk of invasive disease was mainly associated with underlying conditions such as malnutrition, Sickle cell disease and and immune suppression. Evidence of multi-drug resistance emerging and systematic surveillance is needed.

Limitations Retrospect study with large data gaps in both metadata and clinical data. Only samples from Western region were serotyped and comprised broad clinical specimens- this may mask geograhical differences. Serotype was limited to the serogroups A to G and only those in groups B and D could were further characterized to the serovar level.

Dr. Richard Bradbury Dr. Martin Antonio Dr. Brenda Kwambana-Adams Acknowledgement Dr. Martin Antonio Dr. Brenda Kwambana-Adams Dr. Richard Bradbury Mr. Bola Lawal Dr. Davis Nwakanma Dr. Ousman Secka

Thank you 

Results: Total sample distribution Sample type S.Typhimurium S.Enteritidis S. Typhi S. arizonae Other NTS ⃰ Total Blood 35 8 16 1 46 106 Stool 6 109 123 CSF Urine 7 Asp/Abs/pus 2 43 9 22 3 168 245 Broad range of disease conditions: Bacteraemia ⃰ Not serotyped due to insufficient antisera or belong to other serovars