Wellcome International Fellow - Dr Samuel Kariuki

Wellcome International Fellow - Dr Samuel Kariuki

Sam utilises molecular tools to investigate the field epidemiology of major enteric infections and antimicrobial resistance ecology and transmission in Kenya and the region. Infections of major public health importance here include invasive non-typhoidal salmonella disease, cholera, typhoid and dysentery.



Sam Kariuki is Director of the Centre for Microbiology Research at the Kenya Medical Research Institute (KEMRI) and co-ordinator of the postgraduate Medical Microbiology Course hosted by the Institute in Nairobi.

Sam graduated with a Bachelor of Veterinary Medicine from the University of Nairobi in 1989 and then obtained a MSc in Pharmacology and Toxicology, University of Nairobi in 1991. He obtained his PhD (Tropical Medicine) from the University of Liverpool in 1997.

As a postdoctoral fellow funded by the Wellcome Trust, Sam researched on the epidemiology and molecular characterisation of invasive non-typhoidal salmonellosis (NTS), which is endemic in sub-Saharan Africa. NTS is common in the region in HIV-positive adults and in children where the infection causes high morbidity and mortality. Utilising basic molecular tools, Sam hypothesised that person-to-person rather than zoonotic transmission was playing a significant role in the epidemiology of community-acquired NTS. Despite scepticism from some scientists this has proven to be correct, a conclusion reached through joint genome analysis linked to field epidemiology carried out with the Sanger Institute.

Sam also works in the area of improving food hygiene through surveillance of other enteric pathogens including cholera, dysentery, typhoid and E. coli contamination through the food chain, funded by the World Health Organisation (WHO) and the Food and Agriculture Organization (FAO). Because antibiotic resistance is a major problem in the region, Sam is also involved in routine surveillance and monitoring of resistance and chairs the national and regional working groups on antimicrobial resistance. He is now an internationally recognised authority in his field and mentors local African scientists through the postgraduate training courses hosted by KEMRI. Importantly, his laboratory is embedded in a government research institute and is largely independent of core Western funding. However, his laboratory is closely linked to the Wellcome Trust Clinical Unit in Kilifi headed by Kevin Marsh.

Selected publications

Antibacterial resistance in sub-Saharan Africa: an underestimated emergency.
Kariuki S and Dougan G
Annals of the New York Academy of Sciences 2014;1323;43-55
PUBMED: 24628272; PMC: 4159419; DOI: 10.1111/nyas.12380

Antibiotic resistance-the need for global solutions.
Laxminarayan R, Duse A, Wattal C, Zaidi AK, Wertheim HF, Sumpradit N, Vlieghe E, Hara GL, Gould IM, Goossens H, Greko C, So AD, Bigdeli M, Tomson G, Woodhouse W, Ombaka E, Peralta AQ, Qamar FN, Mir F, Kariuki S, Bhutta ZA, Coates A, Bergstrom R, Wright GD, Brown ED and Cars O
The Lancet. Infectious diseases 2013;13;12;1057-98
PUBMED: 24252483; DOI: 10.1016/S1473-3099(13)70318-9

A study on the geophylogeny of clinical and environmental Vibrio cholerae in Kenya.
Kiiru J, Mutreja A, Mohamed AA, Kimani RW, Mwituria J, Sanaya RO, Muyodi J, Revathi G, Parkhill J, Thomson N, Dougan G and Kariuki S
PloS one 2013;8;9;e74829
PUBMED: 24066154; PMC: 3774669; DOI: 10.1371/journal.pone.0074829

Intestinal parasitic infections in children presenting with diarrhoea in outpatient and inpatient settings in an informal settlement of Nairobi, Kenya.
Mbae CK, Nokes DJ, Mulinge E, Nyambura J, Waruru A and Kariuki S
BMC infectious diseases 2013;13;243
PUBMED: 23705776; PMC: 3673844; DOI: 10.1186/1471-2334-13-243

Intracontinental spread of human invasive Salmonella Typhimurium pathovariants in sub-Saharan Africa.
Okoro CK, Kingsley RA, Connor TR, Harris SR, Parry CM, Al-Mashhadani MN, Kariuki S, Msefula CL, Gordon MA, de Pinna E, Wain J, Heyderman RS, Obaro S, Alonso PL, Mandomando I, MacLennan CA, Tapia MD, Levine MM, Tennant SM, Parkhill J and Dougan G
Nature genetics 2012;44;11;1215-21
PUBMED: 23023330; PMC: 3491877; DOI: 10.1038/ng.2423

Escherichia coli strains from Kenyan patients carrying conjugatively transferable broad-spectrum β-lactamase, qnr, aac(6')-Ib-cr and 16S rRNA methyltransferase genes.
Kiiru J, Kariuki S, Goddeeris BM, Revathi G, Maina TW, Ndegwa DW, Muyodi J and Butaye P
The Journal of antimicrobial chemotherapy 2011;66;7;1639-42
PUBMED: 21474478; DOI: 10.1093/jac/dkr149

Typhoid in Kenya is associated with a dominant multidrug-resistant Salmonella enterica serovar Typhi haplotype that is also widespread in Southeast Asia.
Kariuki S, Revathi G, Kiiru J, Mengo DM, Mwituria J, Muyodi J, Munyalo A, Teo YY, Holt KE, Kingsley RA and Dougan G
Journal of clinical microbiology 2010;48;6;2171-6
PUBMED: 20392916; PMC: 2884483; DOI: 10.1128/JCM.01983-09

Epidemic multiple drug resistant Salmonella Typhimurium causing invasive disease in sub-Saharan Africa have a distinct genotype.
Kingsley RA, Msefula CL, Thomson NR, Kariuki S, Holt KE, Gordon MA, Harris D, Clarke L, Whitehead S, Sangal V, Marsh K, Achtman M, Molyneux ME, Cormican M, Parkhill J, MacLennan CA, Heyderman RS and Dougan G
Genome research 2009;19;12;2279-87
PUBMED: 19901036; PMC: 2792184; DOI: 10.1101/gr.091017.109

Public health. The cholera crisis in Africa.
Bhattacharya S, Black R, Bourgeois L, Clemens J, Cravioto A, Deen JL, Dougan G, Glass R, Grais RF, Greco M, Gust I, Holmgren J, Kariuki S, Lambert PH, Liu MA, Longini I, Nair GB, Norrby R, Nossal GJ, Ogra P, Sansonetti P, von Seidlein L, Songane F, Svennerholm AM, Steele D and Walker R
Science (New York, N.Y.) 2009;324;5929;885
PUBMED: 19443768; DOI: 10.1126/science.1173890

Invasive multidrug-resistant non-typhoidal Salmonella infections in Africa: zoonotic or anthroponotic transmission?
Kariuki S, Revathi G, Kariuki N, Kiiru J, Mwituria J, Muyodi J, Githinji JW, Kagendo D, Munyalo A and Hart CA
Journal of medical microbiology 2006;55;Pt 5;585-91
PUBMED: 16585646; DOI: 10.1099/jmm.0.46375-0

Characterisation of community acquired non-typhoidal Salmonella from bacteraemia and diarrhoeal infections in children admitted to hospital in Nairobi, Kenya.
Kariuki S, Revathi G, Kariuki N, Kiiru J, Mwituria J and Hart CA
BMC microbiology 2006;6;101
PUBMED: 17173674; PMC: 1764016; DOI: 10.1186/1471-2180-6-101