Skip directly to site content Skip directly to page options Skip directly to A-Z link Skip directly to A-Z link Skip directly to A-Z link
Volume 21, Number 8—August 2015

Malaria Prophylaxis Failure with Doxycycline, Central African Republic, 2014

Cite This Article

To the Editor: Doxycycline is an effective antimalarial prophylactic drug when administered as a monotherapy 1 day before, daily during, and for 4 weeks after travel to an area where malaria is endemic (1). Doxycycline is currently a recommended chemoprophylactic regimen for travelers visiting areas where malaria is endemic and has a high prevalence of chloroquine or multidrug resistance (2). The World Health Organization also recommends doxycycline in combination with quinine or artesunate as the second-line treatment for uncomplicated Plasmodium falciparum malaria (3).

Prophylactic and clinical failures of doxycycline against P. falciparum have been associated with both inadequate doses (4) and poor patient compliance (5). However, resistance can also explain failures of prophylaxis. Cycline resistance in Plasmodium spp. has been documented as a consequence of selective drug pressure in a P. berghei murine malaria model (6). The administration of increasing doses of minocycline to mice infected with 1 × 107 parasites for 86 successive passages over 600 days made it possible to obtain a resistant P. berghei strain with a median drug inhibitory concentration (IC50) of 600 mg/kg/d, which is 6-fold higher than that of the susceptible starting strain (100 mg/kg/d) (6). A Bayesian mixture modeling approach identified 3 different phenotypes (low, medium, and high doxycycline IC50 phenotypic groups) among P. falciparum clinical isolates (7,8). Using 90 isolates from 14 countries, we demonstrated that increases in copy numbers of P. falciparum metabolite drug transporter gene (Pfmdt, PFE0825w) and P. falciparum GTPase TetQ gene (PfTetQ, PFL1710c) are associated with reduced susceptibility to doxycycline (9); this association was later confirmed (7). In addition, isolates with PfTetQ KYNNNN motif repeats are associated with in vitro reduced susceptibility to doxycycline and with a significantly higher probability of having an IC50 above the doxycycline resistance threshold of 35 μM (9,10).

We report a case of documented malaria prophylactic failure with doxycycline in a 26-year-old soldier from France who was infected during a 6-week peacekeeping mission in the Central African Republic in 2014. According to his colleagues and the collective prophylaxis intake, the patient had been compliant with doxycycline prophylaxis. On admission to a hospital in Bangui, Central African Republic, the patient had fever (temperature 40°C), alteration of consciousness, and hypotension. The diagnosis of severe P. falciparum malaria was made on the basis of a rapid diagnostic test confirmed by a blood smear test (parasitemia 8% on day 0). Intravenous artesunate was immediately started, in accordance with World Health Organization recommendations (3). The patient’s clinical condition worsened, and kidney failure developed. Twenty-four hours later (day 1), he was transported by airplane to Bégin Military Teaching Hospital (Saint-Mandé, France). On admission, he had cerebral edema and a P. falciparum parasitemia level of 0.7%. The patient died 1 day later (day 2).

A blood sample obtained from the patient on day 1 in France showed a doxycycline concentration of 195 μg/mL plasma. This concentration, which was determined by liquid chromatography coupled with tandem mass spectrometry, was compatible with a last doxycycline uptake 1 day before diagnosis (day −1). The finding of the expected doxycycline plasma concentration, together with assurances (colleague’s statements and collective intake of doxycycline) that the patient had followed the drug regimen, was sufficient to suggest prophylaxis failure in a treatment-compliant patient.

The P. falciparum sample obtained from the patient on arrival in France was evaluated for in vitro susceptibility to doxycycline, but the evaluation was unsuccessful. The number of copies of PfTetQ and Pfmdt genes were evaluated relative to the single-copy P. falciparum β-tubulin gene (pfβtubulin), as previously described (7,8). The sample was assayed in triplicate. The 2–ΔΔCt method (where Ct indicates cycle threshold) of relative quantification was used and adapted to estimate the number of copies of Pfmdt and PfTetQ by using the formula ΔΔCt = (Ct (PfTetQ or Pfmdt) − Ct (Pfβtubulin))Sample – (Ct (PfTetQ or Pfmdt) − Ct (Pfβtubulin))Calibrator. Genomic DNA extracted from 3D7 P. falciparum, which has a single copy of each gene, was used for calibrator sample; Pfβtubulin served as the control housekeeping gene. The experiment was assayed twice. The sample had 2 copies of PfTetQ and Pfmdt genes, which suggested decreased in vitro susceptibility of the sample to doxycycline (8,9). The genotyping of PfTetQ sequence polymorphisms was done by using conventional methods with the primers PfTetQ forward (5′-TCACGACAAATGTGCTAGATAC-3′) and PfTetQ reverse (5′-ATCATCATTTGTGGTGGATAT-3′), as previously described (10). Two PfTetQ KYNNNN motif repeats were found in the sample; <3 KYNNNN motif repeats are predictive of in vitro P. falciparum–resistant parasites with an IC50 of >35 μM (odds ratio 15) (10). The 2 copies of Pfmdt and the 2 KYNNNN motif repeats have been shown to be associated with parasites with in vitro resistance to doxycycline (9,10). The association of doxycycline resistance (prophylactic failure with statement of correct intake and the presence of an expected concentration) with increased Pfmdt copies and decreased PfTetQ KYNNNN motif repeats suggest that these molecular markers are predictive markers of doxycycline resistance that can be used for resistance surveillance.


Marylin Madamet, Tiphaine Gaillard, Guillaume Velut, Cecile Ficko, Pascal Houzé, Claire Bylicki, Stéphane Mérat, Sandrine Houzé, Nicolas Taudon, Rémy Michel, Pierre Pasquier, Christophe Rapp, and Bruno PradinesComments to Author 
Author affiliations: Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France (M. Madamet, N. Taudon, B. Pradines); Aix Marseille Université, Marseille, France (M. Madamet, N. Taudon, B. Pradines); Centre National de Référence du Paludisme, Marseille (M. Madamet, N. Taudon, B. Pradines); Hôpital d’Instruction des Armées Saint Anne, Toulon, France (T. Gaillard); Centre d’Epidémiologie et de Santé Publique des Armées,; Marseille, France (G. Velut, R. Michel); Hôpital d’Instruction des Armées Begin, Saint Mandé, France (C. Ficko, S. Mérat, P. Pasquier, C. Rapp); Hôpital Saint-Louis, Paris, France (P. Houzé); Hôpital Bichat Claude Bernard, Paris (S. Houzé); Institut pour la Recherche et le Développement, Paris (S. Houzé),; Université Paris Descartes, Paris (S. Houzé); Centre National de Référence du Paludisme, Paris (S. Houzé); Antenne Médicale de Fontevraud, Fontevraud, France (C. Bylicki); Ecole du Val-de-Grâce, Paris (R. Michel, C. Rapp)



  1. Briolant  S, Fusaï  T, Rogier  C, Pradines  B. Tetracycline antibiotics in malaria. Open Trop Med J. 2008;1:3146. DOIGoogle Scholar
  2. Institut National de Veille Sanitaire. Recommandations sanitaires pour les voyageurs, 2014. Bulletin Epidémiologique Hebdomadaire. 2014;16–17:264311.
  3. World Health Organization. Guidelines for the treatment of malaria, 2nd ed. Geneva: The Organization; 2010.
  4. Pang  L, Limsomwong  N, Singharaj  P. Prophylactic treatment of vivax and falciparum malaria with low-dose doxycycline. J Infect Dis. 1988;158:11247. DOIPubMedGoogle Scholar
  5. Wallace  MR, Sharp  TW, Smoak  B, Iriye  C, Rozmajzl  P, Thornton  SA, Malaria among United States troops in Somalia. Am J Med. 1996;100:4955. DOIPubMedGoogle Scholar
  6. Jacobs  RL, Koontz  LC. Plasmodium berghei: development of resistance to clindamycin and minocycline in mice. Exp Parasitol. 1976;40:11623. DOIPubMedGoogle Scholar
  7. Briolant  S, Baragatti  M, Parola  P, Simon  F, Tall  A, Sokhna  C, Multinormal in vitro distribution model suitable for the distribution of Plasmodium falciparum chemosusceptibility to doxycycline. Antimicrob Agents Chemother. 2009;53:68895. DOIPubMedGoogle Scholar
  8. Gaillard  T, Briolant  S, Houzé  S, Baragatti  M, Wurtz  N, Hubert  V, PftetQ and pfmdt copy numbers as predictive molecular markers of decreased ex vivo doxycycline susceptibility in imported Plasmodium falciparum malaria. Malar J. 2013;12:414. DOIPubMedGoogle Scholar
  9. Briolant  S, Wurtz  N, Zettor  A, Rogier  C, Pradines  B. Susceptibility of Plasmodium falciparum isolates to doxycycline is associated with pftetQ sequence polymorphisms and pftetQ and pfmdt copy numbers. J Infect Dis. 2010;201:1539. DOIPubMedGoogle Scholar
  10. Achieng  AO, Ingasia  LA, Juma  DW, Cheruiyot  AC, Okudo  CA, Yeda  RA, Reduced in vitro doxycycline susceptibility in Plasmodium falciparum field isolates from Kenya is associated with PftetQ KYNNNN sequence polymorphism. Antimicrob Agents Chemother. 2014;58:58949. DOIPubMedGoogle Scholar


Cite This Article

DOI: 10.3201/eid2108.150524

Medline indexes "Open Trop Med J." but cannot find a listing for reference 1 "Briolant, Fusaï, Rogier, Pradines, 2008". Please check the reference for accuracy.

Related Links


Table of Contents – Volume 21, Number 8—August 2015

EID Search Options
presentation_01 Advanced Article Search – Search articles by author and/or keyword.
presentation_01 Articles by Country Search – Search articles by the topic country.
presentation_01 Article Type Search – Search articles by article type and issue.



Please use the form below to submit correspondence to the authors or contact them at the following address:

Bruno Pradines, Unité de parasitologie et d’entomologie, Institut de recherche biomédicale des Armées, BP 73, 91223 Brétigny sur Orge, France

Send To

10000 character(s) remaining.


Page created: July 15, 2015
Page updated: July 15, 2015
Page reviewed: July 15, 2015
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.