One Health Bacteriology

“One Health is a collaborative, multisectoral, and transdisciplinary approach — working at the local, regional, national, and global levels — with the goal of achieving optimal health outcomes recognizing the interconnection between people, animals, plants, and their shared environment” (

Bacterial infectious diseases are common medical problems in developing countries. Due to limited diagnostic facilities, the causative agents and sources of infection as well transmission pathways often remain unidentified. Empiric treatment is a common practice in facilities with scarce resources, fostering the emergence of antibiotic resistance leading to difficult-to treat infections. Due to the absence of effective monitoring, circulating bacterial strains and changes over time are not always entirely understood.
Also, infections seen in humans are often zoonoses representing a public health concern around the globe. This is linked to our close relationship with animals in agriculture and in the environment in particular affecting rural areas of developing countries. Zoonotic pathogens can be transmitted to humans through direct contact or through food, water or the environment. Overuse of antibiotics in animal husbandry has significantly contributed to the increase of multi drug resistant bacteria, also seen in humans. Bacteria are capable of adapting to different environments. They for example can persist on hospital surfaces, in water and soil for extended periods exhibiting a transmission reservoir and harbouring antibiotic resistance, subsequently causing human infections.

Our research interests include the generation and comparison of bacteriological data from humans, animals and the environment in countries with limited resources. A special research focus is on transmission and the identification of transmission reservoirs of antibiotic-resistant bacteria in rural areas of sub-Saharan African countries. Our activities will support and guide patient management and public health measures.

Genetic adaptation of Salmonella enterica in human and animal reservoirs in sub-Saharan Africa (SASSA)

Salmonella enterica cause more than 1.2 million annual deaths worldwide, the majority occurring in resource-limited countries. Infections with non-typhoidal Salmonella (NTS) are typically limited to gastrointestinal disease in industrialized countries. In contrast, in sub-Saharan Africa (SSA), NTS are the most frequent cause of bacterial bloodstream infections in adults and children, associated with high fatality rates. In both industrialized countries and SSA, the serovars Typhimurium and Enteritidis cause the majority of infections. In recent years, Salmonella enterica in SSA have also become increasingly resistant to locally available antibiotics, leading to the substantial burden of NTS infections in Africa.
In industrialised countries, infections with NTS are typically of zoonotic origin with regular food-borne outbreaks. In developing countries, studies on transmission reservoirs are limited but previously it has been found that African Salmonella strains have genetically developed by adapting to different hosts or to the environment.
Our research activities focus on transmission including human, animal and environmental reservoirs, antibiotic resistance and genomic characterisation of circulating Salmonella strains in SSA in order to suggest the implementation of effective control strategies.

Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
Agogo Presbyterian Hospital, Agogo, Ghana
National Institute for Medical Research (NIMR) in Tanga, Tanzania
Korogwe District hospital, Korogwe, Tanzania

German Research Foundation (DFG)

Richard Phillips & Denise Dekker

Antibiotic-resistant enteric pathogens in human and animal reservoirs 

In resource-limited countries, broad-spectrum antibiotics are often prescribed empirically without microbiological diagnosis. This overuse of antibiotics in human medicine significantly contributes to the emergence and the increase of multidrug-resistance. In addition, the use of antibiotics in animal husbandry as growth promoters and for prophylaxis and treatment of infection aggravates this problem. Often, in countries where resources are limited, animal farming is a common occupancy and people often live in close proximity to animals. Animals and meat products have been suggested as an important source for drug resistant enteric pathogens including Campylobacter spp., Arcobacter spp., Salmonella enterica, ESBL-producing Escherichia coli and Klebsiella pneumoniae in SSA countries. Transmission of these bacteria might occur by direct contact or consumption of contaminated meat products, leading to the colonization of the intestinal tract and eventually to infections. So far, the degree to which animals play a role as a reservoir for the transmission of multi drug resistant bacteria has not been studied on genotype level in rural areas of SSA. Within this project, Campylobacter spp., Arcobacter spp., Salmonella enterica, ESBL-producing E. coli and K. pneumoniae genomes collected from human and animals will be compared to examine transmission between human and animal in rural areas of Tanzania and Ghana.

Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
Agogo Presbyterian Hospital, Agogo, Ghana
National Institute for Medical Research (NIMR) in Tanga, Tanzania
Korogwe District hospital, Korogwe, Tanzania

German Research Foundation (DFG)

Richard Phillips & Denise Dekker

Paediatric Phase I/II study of a vaccine against invasive non-typhoidal salmonellosis in sub-Saharan Africa (PEDVAC)

Invasive disease with non-typhoidal Salmonella in SSA is associated with increasing antibiotic resistance (AMR) and has been classified by the World Health Organization as high priority for developing new antibiotics. Despite high case fatality rates, particularly in children <5 years of age in SSA countries, no vaccine is currently available. The burden caused by NTS infections and increasing AMR strongly encourage for prompt development of an effective vaccine. A novel vaccine, is currently being developed by GSK Biologicals and GSK Vaccines Institute for Global Health, targeting the serovars Typhimurium and Enteritidis, the most common causative agents of African invasive NTS. Within a large consortium, a paediatric Phase I/II study will be launched early in 2021 in Ghana. The focus of our group will be on antibiotic resistant genotypes of iNTS-causing Salmonella strains. The information gained will not only inform on circulating Salmonella serovars and genotypes but will also inform on the development of AMR pathogens in SSA.

Kwame Nkrumah University of Science and Technology (KNUST), Ghana
Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
Agogo Presbyterian Hospital, Agogo, Ghana
University of Siena, Italy
MMGH Consulting GmbH, Switzerland
GSK Vaccine Institute for Global Health (GVGH), Italy

European and Developing Countries Clinical Trials Partnership (EDCTP)

Richard Phillips & Denise Dekker

One Health“: AMR in environmental reservoirs and colonizing antibiotic resistant bacteria“-Improving antibiotic use in West Africa: exploring current situation and developing strategies for behavior change (BCHANGE)

Antibiotic resistance is rising to dangerously high levels in all parts of the world and becoming one of the largest threats to global health and food security. New resistance mechanisms are emerging and spreading globally, threatening our ability to treat common infectious diseases. Antibiotic resistance occurs naturally but is accelerated by poor infection prevention and control and above all by the inappropriate use and overuse of antibiotics. Epidemiological studies have demonstrated a direct relationship between antibiotic consumption and the emergence and dissemination of resistant bacteria. Antibiotic use is not limited to humans but is also widespread in livestock farming as growth promoters, as prophylaxis and to treat infections. The antibiotics used in livestock are ingested by humans when they consume food: molecular detection methods have demonstrated that resistant bacteria in farm animals reach consumers through meat products. The irrational use of antimicrobials is certainly a complex and multifactorial problem in developing countries, and a proper understanding of the problem is necessary for the development of effective control policies. Without behavior change, antibiotic resistance will remain a major threat, even if new medicines are developed.
The overall study is led by project partners from Heidelberg (HIGH) and France (IRD) in collaboration with the BNITM and all partners.
This project aims at understanding and quantify perceptions and uses related to antibiotics among health care workers, communities and livestock farmers and defining patterns of accessing and utilizing antibiotics. Further an intervention to improve awareness and understanding of antimicrobial resistance through effective communication, education and training using a stakeholder-driven approach shall be defined. The focus of our group within this project will be assessing baseline data on AMR pathogens along the food chain in Nouna, Burkina Faso and Kumasi, Ghana.


Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana

Nogouchi memorial Institute for Medical Research (NMIMR), Accra, Ghana

Council for Scientific and Industrial Research-Animal Research Institute, Accra, Ghana (CSIR-ARI)

Nouna Health Research Centre (CRSN), Nouna, Burkina Faso

Institute de Recherche en Sciences de la Santé (IRSS), Ouagadougou, Burkina Faso

Centre International de Recherche-Devéloppement sur l’Elevage en zone Subhumide (CIRDES), Bobo Dioulasso, Burkina Faso

French National Research Institute for Sustainable Development (IRD)

Heidelberg University Hospital, Heidelberg Institute of Global health (HIGH)

St Francis Xavier Hospital, Assin Fosu, Central Region

Bundesministerium für Bildung und Forschung (BMBF)
French Research National Agency (ANR)

John Amuasi & Denise Dekker

Development of standardized AMR laboratories for AMR surveillance in sub-Saharan Africa (AMR, STAND AMR, EXPAND AMR)

The spread of antimicrobial resistance (AMR) is a major challenge for health systems worldwide, also affecting many African countries. The majority of bacterial infections with resistant pathogens in sub-Saharan Africa still go undetected and empiric treatment of infections is common. The reason behind are lack of microbiology laboratories, that are capable of performing bacterial culture and antibiotic susceptibility testing, particularly in rural areas of sub-Saharan Africa. Therefore, the GHP funded project “development of standardized AMR laboratories” has so far built and set up three fully functioning AMR microbiology laboratories in three different geographical locations of Ghana, namely Agogo (Asante Akim North District), Assin Fosu (Assin Fosu Municipal) and Agroyesum (Amansie West District). The established laboratories are standardized and are able to process clinical specimens such as blood, urine and stool samples as well as perform antibiotic susceptibility testing according to the guidelines of the WHO Global Antimicrobial Resistance Surveillance System (GLASS). The established AMR surveillance systems will inform on circulation and emerging AMR bacterial strains and will eventually lead to improved patient care by allowing targeted antibiotic treatment. In 2022, this work will be expanded to another study site in Tanzania in collaboration with the National Institute for Medical Research (NIMR) and the Bombo Referral Hospital in Tanga, Tanzania.

Kwame Nkrumah University of Science and Technology (KNUST), Ghana
Kumasi Centre for Collaborative Research in Tropical Medicine (KCCR), Kumasi, Ghana
Agogo Presbyterian Hospital, Agogo, Ghana
St. Martin’s Hospital, Agroyesum, Ghana
St. Francis Xavier Hospital, Assin Fosu, Ghana
National Institute for Medical Research (NIMR), Tanga/Korogwe, Tanzania 
Bombo Regional Referral Hospital, Tanga, Tanzania

Global Health Programme (GHPP)-Bundesministerium für Gesundheit

John Amuasi & Denise Dekker

The primary goal is to advance clinical development of the vaccine for use in the target population (i.e., infants in sub-Saharan Africa (sSA)) by conducting a pediatric Phase I/II study a sSA country with high medical need. (PEDVAC-iNTS)

Funder: European & Developing Countries Clinical Trials Partnership (EDCTP)

Amount: EUR Total 267.978,99

Project period: 03/2021 – 02/2025


Title: Improving antibiotics use in West Africa: exploring current situation and developing strategies for behaviour change (AMR-B-CHANGE)

Funder: German Federal Ministry of Education and Research, BMBF and French National Research Agency (ANR)

Amount: Total € 303.125,00

Project period: 01 January 2021 to 31 December 2023


Title: AMR surveillance

Funder: German Ministry of Health (BMG)

Amount: Total € 364.000,00

Project period: 2022


Title: Genetic adaptation of non-typhoidal salmonella within human and animal reservoirs in sub-Sahara Africa (SASSA)

Funder: German Research Association, DFG

Amount: Total € 1. 014,079

Project period: February 2019 to February 2022 (No Cost Extension until December 2022)













  • Hogan B, Rakotozandrindrainyr, Al Emran H, Dekker D et al. Prevalence of nasal colonisation by methicillin-sensitive and methicillin-resistant Staphylococcus aureus amoimg healthcare workers and students in Madagascar. B;C Infectious Diseases 2016 16;420 Doi 10.1186/s12879-016-17336




  • Al-Emran HM, Eibach D, Krumkamp R, Ali M, Baker S, Biggs HM, Bjerregaard-Andersen M, Breiman RF, Clemens JD, Crump JA, Cruz Espinoza LM, Deerin J, Dekker DM et al. A Multicountry Molecular Analysis of Salmonella enterica Serovar Typhi With Reduced Susceptibility to Ciprofloxacin in Sub-Saharan Africa.Clin Infect Dis. 2016 Mar 15;62 Suppl 1:S42-6. PMID: 26933020. [9,4]


  • Eibach D, Al-Emran HM, Dekker DM et al. The Emergence of Reduced Ciprofloxacin Susceptibility in Salmonella enterica causing bloodstream Infections in Rural Ghana. Clin Infect Dis. 2016 Mar 15;62 Suppl 1:S32-6. PMID: 26933017. [9,4]


  • Cruz Espinoza LM, Nichols C, Adu-Sarkodie Y, Al-Emran HM, Baker S, Clemens JD, Dekker DM et al.  Variations of Invasive Salmonella Infections by Population Size in Asante Akim Municipal, Ghana. Clin Infect Dis. 2016 Mar 15;62 Suppl 1:S17-22. PMID: 26933015. [9,4]


  • Eibach D, Campos CB, Krumkamp R, Al-Emran H, Dekker D et al. Extended spectrum beta-lactamases producing Enterobacteriaceae causing bloodstream infections in rural Ghana, 2007-2012. Int J Med Microbiol. 2016 Jun;306(4):249-54. doi: 10.1016/j.ijmm.2016.05.006. Epub 2016 May 10


  • Dekker D et al. Antibiotic resistance and clonal diversity of invasive Staphylococcus aureus in the rural Ashanti Region, Ghana, BMC Infectious Diseases 2016 16:7 20 DOI 10,1186/s 12879-016-2048-3


  • Eibach D, Nagel M, Hogan B, Azuure C, Krumkamp R, Dekker D et al. Nasal carriage of Staphylococcus aureus among children in the Ashanto region of Ghana. PLoS ONE 2017 12(1): e0170320. doi:10.1371/journal.pone.0170320






  • Hogan B, Ammer L, Zimmermann Z, Binger T, Krumkamp R, Sarpong N, Rettig T, Dekker D et al.  Burden of influenza among hospitalized febrile children in Ghana. Influenza Other Respir Viruses. 2017 Oct 9. Doi 10.1111/irv.12507



  • Hogan B, Eibach D, Krumkamp R, Sarpong N, Dekker D et al. Malaria co-infections in febrile paediatric inpatients: a hospital-based study from Ghana.  Clin Infect Dis. 2018 Feb 2. doi: 10.1093/cid/cix1120.2018


  • Hogan B, Eibach D, Krumkamp R, Sarpong N, Dekker D, Kreuels B, Maiga-Ascofaré O, Gyau Boahen K, Wiafe Akenten C, Adu-Sarkodie Y, Owusu-Dabo E, May J; Fever Without Source (FWS) Study Group. Malaria Coinfections in Febrile Pediatric Inpatients: A Hospital-Based Study From Ghana. Clin Infect Dis. 2018; 66(12):1838-1845



  • Dekker D et al. Characterization of Salmonella enterica from invasive bloodstream infections and water sources in rural Ghana. BMC Infect Dis. 2018 Jan 19;18(1):47. doi: 10.1186/s12879-018-2957-4.


  • Eibach D, Dekker D et al. Extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in local and imported poultry meat in Ghana. Vet Microbiol. 2018 Ap; 217:7-12 doi:10.1016/j. vetmic.2018.02.023. Epub 2018 Mar 22



  • Frickmann H, Wiemer DF, Wassill L, Hinz R, Rojak S, Wille A, Loderstädt U, Schwarz NG, von Kalckreuth V, Im J, Jeon HJ, Marks F, Owusu-Dabo E, Sarpong, May J, Eibach E, Dekker D. Loop-mediated isothermal amplification-based detection of typhoid fever on an automated Genie II Mk2 system – a case-  control-based approach. Acta Trop. 2018 Dec 5;190:293-295


  • Aldrich C, Hartmann HFeasey N, Chattaway MA, Dekker D, Al-Emran H, Larkin L, McCormick j, Sarpong N, Le Hello S, Adu-Sarkodie Y, Panzner U, Park S E, Im J, Marks F, May J, Dallman TJ, Eibach D. Emergence of phylogenetically diverse and fluoroquinolone resistant Salmonella Enteritidis as a cause of invasive nontyphoidal Salmonella disease in Ghana. PLoS Negl Trop Dis 2019 Jun 20;13(6)


  • Dekker D, Eibach D, Boahen KG, Akenten CW, Pfeifer Y, Zautner AE, Mertens E, Krumkamp R, Jaeger A, Flieger A, Owusu-Dabo E, May J. Fluoroquinolone-resistant Salmonella enterica, Campylobacter and Arcobacter butzleri from local and imported poultry meat in Kumasi, Ghana. Foodborne Pathog Dis. 2019 May;16(5):352-358.



  • Toy T, Pak GD, Duc TP, Campbell JI, El Tayeb MA, Von Kalckreuth V, Im J, Panzner U, Cruz Espinoza LM, Eibach D, Dekker DM, Park SE, Jeon HJ, Konings F, Mogeni OD, Cosmas L, Bjerregaard-Andersen M, Gasmelseed N, Hertz JT, Jaeger A, Krumkamp R, Ley B, Thriemer K, Kabore LP, Niang A, Raminosoa TM, Sampo E, Sarpong N, Soura A, Owusu-Dabo E, Teferi M, Yeshitela B, Poppert S, May J, Kim JH, Chon Y, Park JK, Aseffa A, Breiman RF, Schütt-Gerowitt H, Aaby P, Adu-Sarkodie Y, Crump JA, Rakotozandrindrainy R, Meyer CG, Sow AG, Clemens JD, Wierzba TF, Baker S, Marks F. Multicountry Distribution and Characterization of Extended-spectrum beta-lactamase-associated Gram-negative bacteria from Bloodstream Infections in Sub-Saharan Africa. Clin Infect Dis. 2019 Oct 30;69(Suppl 6):S449-S458. doi: 10.1093/cid/ciz450.


  • Köller T, Hahn A, Altangerel E, Verweij J J , Landt O, Kann S, Dekker D, May J, Loderstädt U,  Podbielskia A, Frickmann H. Comparison of commercial and in-house real-time PCR platforms for 15 parasites and microsporidia in human stool samples without a gold standard. Acta Tropica 207 (2020) 105516


  • Krumkamp R, Oppong K, Hogan B, Strauss R, Frickmann H, Wiafe Akenten C, Boahen K, Rickerts V, McCormick Smith I, Groß U, Schulze M, Jaeger A, Loderstädt U, Sarpong N, Owusu-Dabo E, May J, Dekker D. Spectrum of antibiotic resistant bacteria and fungi isolated from chronically infected wounds in a rural district hospital in Ghana. PlosOne 2020


  • Herr W, Krumkamp R, Hogan B, Dekker D et al. A cross-sectional study on risk factors for infection with Parvovirus B19 and the association with anaemia in a febrile paediatric population in Ghana. Nat. Research 2020. 10:15695;doi:10.1038.


  • Moirongo RM, Lorenz E, Ntinginya NE, Dekker D et al. Regional Variation of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Enterobacterales, Fluoroquinolone-Resistant Salmonella enterica and Methicillin-Resistant Staphylococcus aureus Among Febrile Patients in Sub-Saharan Africa. Front Microbiol 2020;11:567235; doi:10.3389


  • Wolters M, Frickmann H, Christner M, Both A, Rohde H, Oppong K, Wiafe Akenten C, May j, Dekker D. Molecular Characterization of Staphylococcus aureus isolated from chronic wounds in rural Ghana. MDPI 2020, 8,2052;doi:10.3390/microorganisms8122052


  • Park SE, Pham DT, Pal GD, Panzner U, et. Al. The genomic epidemiology of multi-drug resistant nontyphoidal Salmonella causing invasive disease in sub-Saharan Africa. Doi 10.1101/2020.12.11.422246


  • Tichkule S, Rex AR, van Oosterhout C, Sannella AR, Krumkamp R, Aldrich C, Maiga-Ascofare O, Dekker D et al. Comparative genomics revealed adaptive admixture in Cryptosporidium hominis in Africa: Microbial genomics 2021;7:000493, Doi10.1099.




  • Wiafe Akenten C, Boahen Ky, Marfo KS, Sarpong N, Dekker D, Struck NS, Osei-Tutu L, May J, Humphrey J, Amuasi J, Eibach D. Bloodstream infection with Acinetobacter baumannii in a Plasmodium falciparum positive infant: a case report. Journal of Med. Case Rep. 15, 46 (2021).


  • Dekker D, Pankok F, Thye T, Taudien S, Oppong K, Wiafe Akenten C, Lamshöft M, Jaeger A, Kaase M, Scheithauer S, Tanida K, Frickmann H, May J, Loderstädt U. Clonal Clusters, Molecular Resistance Mechanisms and Virulence Factors of Gram-Negative Bacteria Isolated from Chronic Wounds in Ghana. Antibiotics 2021, 10, 339. antibiotics10030339



  • Paintsil EK, Ofori LA, Wiafe Akenten C, Fosu D, Ofori S, Lamshöft M, May J, Obiri Danso K, Krumkamp K*, Dekker D*(equally contributed). Antimicrobial usage in commercial and domestic poultry farming in two communities in the Ashanti Region of Ghana. MDPI Antibiotics 2021, 10,800. Doi10.3390


  • Paintsil EK, Ofori L, Adobea S, Wiafe Akenten C, Phillips RO, Maiga-Ascofare O, Lamshöft M, May J, Obiri Danso K, Krumkamp R, Dekker D. Prevalence and Antibiotic Resistance in Campylobacter spp. isolated from humans and food-producing animals in West Africa: a systemic review and meta-analysis. Pathogens 2022 24;11(2):140.10.3390/11020140.


  • Krumkamp R, Kohsar M, Nolte K, Hogan B, Eibach D, Jaeger A, Akenten CW, Drosten C, Boahen KG, Sarpong N, Eckerle I. Pathogens associated with hospitalization due to acute lower respiratory tract infections in children in rural Ghana: a case–control study. Scientific Reports. 2023 Feb 10;13(1):2443.


  • Akenten CW, Ofori LA, Khan NA, Mbwana J, Sarpong N, May J, Thye T, Obiri-Danso K, Paintsil EK, Fosu D, Philipps RO. Prevalence, Characterization, and Antimicrobial Resistance of Extended-Spectrum Beta-Lactamase-Producing Escherichia coli from Domestic Free-Range Poultry in Agogo, Ghana. Foodborne Pathogens and Disease. 2023 Feb 1;20(2):59-66.



  • Zautner AE, Riedel T, Bunk B, Spröer C, Boahen KG, Akenten CW, Dreyer A, Färber J, Kaasch AJ, Overmann J, May J. Molecular characterization of Arcobacter butzleri isolates from poultry in rural Ghana. Frontiers in Cellular and Infection Microbiology. 2023 Jan 25;13:24.



  • Akenten CW, Weinreich F, Paintsil EK, Amuasi J, Fosu D, Loderstädt U, May J, Frickmann H, Dekker D. Intestinal Helminth Infections in Ghanaian Children from the Ashanti Region between 2007 and 2008—A Retrospective Cross-Sectional Real-Time PCR-Based Assessment. Tropical Medicine and Infectious Disease. 2022 Nov 14;7(11):374.


Group leader: Dr Denise Dekker
Phone: +49 40 42818-521 Fax: +49 40 42818-512 E-Mail: dekker(at)

Project Co-ordinator
Charity Wiafe Akenten  

Assistant Project Coordinator

Ellis Kobina Paintsil 

Masters Student

Cynthia Adu Kyeremah

Charlotte Ama Tweneboa Adu

Laboratory Technicians

Esther Adgeiwaa Boaitey (KCCR, Kumasi)

Jones Ankomah (KCCR, Assin Foso)

Benjamin Amoah (KCCR, Agroyesum)

Samson Manu (KCCR, Agroyesum)

Micah Kwartei Quartey (KCCR, Agogo Lab)

Project Manager

Rhoda Mawuko Dorkenoo

Data Officers

Bernard A. B. Essien

Theophilus Coleman (Assin Foso)

Group Leader

Dr Denise Dekker
Phone: +49 40 42818-521
E-Mail :

Project Co-ordinator

Charity Wiafe Akenten
Phone: +233 26 611 8240
E-Mail :

Assistant Project Co-ordinator

Ellis Kobina Paintsil
Phone: +233 20 270 0486
E-Mail :

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