The emerging threat of pre-extensively drug-resistant tuberculosis in West Africa: preparing for large-scale tuberculosis research and drug resistance surveillance.
BACKGROUND
Drug-resistant tuberculosis (TB) is a global public health problem. Adequate management requires baseline drug-resistance prevalence data. In West Africa, due to a poor laboratory infrastructure and inadequate capacity, such data are scarce. Therefore, the true extent of drug-resistant TB was hitherto undetermined. In 2008, a new research network, the West African Network of Excellence for Tuberculosis, AIDS and Malaria (WANETAM), was founded, comprising nine study sites from eight West African countries (Burkina Faso, The Gambia, Ghana, Guinea-Bissau, Mali, Nigeria, Senegal and Togo). The goal was to establish Good Clinical Laboratory Practice (GCLP) principles and build capacity in standardised smear microscopy and mycobacterial culture across partnering laboratories to generate the first comprehensive West African drug-resistance data.


METHODS
Following GCLP and laboratory training sessions, TB isolates were collected at sentinel referral sites between 2009-2013 and tested for first- and second-line drug resistance.


RESULTS
From the analysis of 974 isolates, an unexpectedly high prevalence of multi-drug-resistant (MDR) strains was found in new (6 %) and retreatment patients (35 %) across all sentinel sites, with the highest prevalence amongst retreatment patients in Bamako, Mali (59 %) and the two Nigerian sites in Ibadan and Lagos (39 % and 66 %). In Lagos, MDR is already spreading actively amongst 32 % of new patients. Pre-extensively drug-resistant (pre-XDR) isolates are present in all sites, with Ghana showing the highest proportion (35 % of MDR). In Ghana and Togo, pre-XDR isolates are circulating amongst new patients.


CONCLUSIONS
West African drug-resistance prevalence poses a previously underestimated, yet serious public health threat, and our estimates obtained differ significantly from previous World Health Organisation (WHO) estimates. Therefore, our data are reshaping current concepts and are essential in informing WHO and public health strategists to implement urgently needed surveillance and control interventions in West Africa.
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.|Institute of Tropical Medicine, Antwerp, Belgium.
Florian
F
Gehre
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Jacob
J
Otu
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Lindsay
L
Kendall
University of Ghana Medical School, Accra, Ghana.|Korle-Bu Teaching Hospital, Accra, Ghana.
Audrey
A
Forson
Warren Alpert Medical School of Brown University, Providence, RI, USA.|The Miriam Hospital, Providence, RI, USA.
Awewura
A
Kwara
Korle-Bu Teaching Hospital, Accra, Ghana.
Samuel
S
Kudzawu
College of Medicine, University of Ibadan, Ibadan, Nigeria.|University College Hospital, Ibadan, Oyo, 23402, Nigeria.
Aderemi O
AO
Kehinde
University College Hospital, Ibadan, Oyo, 23402, Nigeria.
Oludele
O
Adebiyi
University College Hospital, Ibadan, Oyo, 23402, Nigeria.
Kayode
K
Salako
National Public Health Laboratory Services, Banjul, The Gambia.
Ignatius
I
Baldeh
National Public Health Laboratory Services, Banjul, The Gambia.
Aisha
A
Jallow
National Public Health Laboratory Services, Banjul, The Gambia.
Mamadou
M
Jallow
Laboratoire National de Reference Mycobacteria, Lome, Togo.
Anoumou
A
Dagnra
Laboratoire National de Reference Mycobacteria, Lome, Togo.
Kodjo
K
Dissé
Laboratoire National de Reference Mycobacteria, Lome, Togo.
Essosimna A
EA
Kadanga
Nigerian Institute of Medical Research, Lagos, Nigeria.
Emmanuel Oni
EO
Idigbe
Nigerian Institute of Medical Research, Lagos, Nigeria.
Catherine
C
Onubogu
Nigerian Institute of Medical Research, Lagos, Nigeria.
Nneka
N
Onyejepu
Laboratoire Bactériologie Virologie Aristide Le Dantec Sénégal, Dakar, Senegal.
Aissatou
A
Gaye-Diallo
Laboratoire Bactériologie Virologie Aristide Le Dantec Sénégal, Dakar, Senegal.
Awa
A
Ba-Diallo
National Institute of Public Health, Bissau, Guinea-Bissau.
Paulo
P
Rabna
National Institute of Public Health, Bissau, Guinea-Bissau.
Morto
M
Mane
SEREFO Program, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
Moumine
M
Sanogo
SEREFO Program, University of Sciences, Techniques and Technologies of Bamako, Bamako, Mali.
Bassirou
B
Diarra
Centre Muraz and the National TB Program, Ouagadougou, Burkina Faso.
Zingue
Z
Dezemon
Centre Muraz and the National TB Program, Ouagadougou, Burkina Faso.
Adama
A
Sanou
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.|Microbiology and Infection Unit, Warwick Medical School, University of Warwick, Coventry, UK.
Madikay
M
Senghore
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.|Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.
Brenda A
BA
Kwambana-Adams
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Edward
E
Demba
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Tutty
T
Faal-Jawara
Institute of Tropical Medicine, Antwerp, Belgium.
Samrat
S
Kumar
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.|Department of Biochemistry, Faculty of Science, University of Yaoundé 1, Yaoundé, Cameroon.
Leopold D
LD
Tientcheu
National Tuberculosis/Leprosy Control Program, Banjul, The Gambia.
Adama
A
Jallow
Health Services, Ministry of Health and Social Welfare, Banjul, The Gambia.
Samba
S
Ceesay
Department of Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, London, UK.|Disease Control and Elimination, Medical Research Council Unit, Serrekunda, The Gambia.
Ifedayo
I
Adetifa
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Assan
A
Jaye
Microbiology and Infection Unit, Warwick Medical School, University of Warwick, Coventry, UK.
Mark J
MJ
Pallen
Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, UK.|Disease Control and Elimination, Medical Research Council Unit, Serrekunda, The Gambia.|Institute of Tropical Medicine, Antwerp, Belgium.
Umberto
U
D'Alessandro
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.|Department of Paediatrics, Imperial College London, London, UK.
Beate
B
Kampmann
GSK Vaccines, Wavre, Belgium.
Richard A
RA
Adegbola
Laboratoire Bactériologie Virologie Aristide Le Dantec Sénégal, Dakar, Senegal.
Souleymane
S
Mboup
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia.
Tumani
T
Corrah
Institute of Tropical Medicine, Antwerp, Belgium.
Bouke C
BC
de Jong
Vaccines and Immunity Theme, Medical Research Council Unit The Gambia, Banjul, The Gambia. mantonio@mrc.gm.|Microbiology and Infection Unit, Warwick Medical School, University of Warwick, Coventry, UK. mantonio@mrc.gm.|Department of Infectious Diseases Epidemiology, London School of Hygiene and Tropical Medicine, London, UK. mantonio@mrc.gm.
Martin
M
Antonio
D000328:Adult; D000354:Africa, Western / Q000453:epidemiology; D000995:Antitubercular Agents / Q000627:therapeutic use; D054908:Extensively Drug-Resistant Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D017410:Practice Guidelines as Topic; D015995:Prevalence; D014944:World Health Organization
D000995:Antitubercular Agents
Capacity building; Drug-resistance surveillance; Extensively drug-resistant tuberculosis; Tuberculosis; West Africa