Analysis of the population structure of Anaplasma phagocytophilum using multilocus sequence typing.
Anaplasma phagocytophilum is a Gram-negative obligate intracellular bacterium that replicates in neutrophils. It is transmitted via tick-bite and causes febrile disease in humans and animals. Human granulocytic anaplasmosis is regarded as an emerging infectious disease in North America, Europe and Asia. However, although increasingly detected, it is still rare in Europe. Clinically apparent A. phagocytophilum infections in animals are mainly found in horses, dogs, cats, sheep and cattle. Evidence from cross-infection experiments that A. phagocytophilum isolates of distinct host origin are not uniformly infectious for heterologous hosts has led to several approaches of molecular strain characterization. Unfortunately, the results of these studies are not always easily comparable, because different gene regions and fragment lengths were investigated. Multilocus sequence typing is a widely accepted method for molecular characterization of bacteria. We here provide for the first time a universal typing method that is easily transferable between different laboratories. We validated our approach on an unprecedented large data set of almost 400 A. phagocytophilum strains from humans and animals mostly from Europe. The typability was 74% (284/383). One major clonal complex containing 177 strains was detected. However, 54% (49/90) of the sequence types were not part of a clonal complex indicating that the population structure of A. phagocytophilum is probably semiclonal. All strains from humans, dogs and horses from Europe belonged to the same clonal complex. As canine and equine granulocytic anaplasmosis occurs frequently in Europe, human granulocytic anaplasmosis is likely to be underdiagnosed in Europe. Further, wild boars and hedgehogs may serve as reservoir hosts of the disease in humans and domestic animals in Europe, because their strains belonged to the same clonal complex. In contrast, as they were only distantly related, roe deer, voles and shrews are unlikely to harbor A. phagocytophilum strains infectious for humans, domestic or farm animals.
Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
Christian
C
Huhn
Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
Christina
C
Winter
Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
Timo
T
Wolfsperger
Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
Nicole
N
Wüppenhorst
Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Katja
K
Strašek Smrdel
Department of Ecology and Parasitology, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Jasmin
J
Skuballa
Department of Ecology and Parasitology, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Miriam
M
Pfäffle
Department of Ecology and Parasitology, Karlsruhe Institute of Technology, Karlsruhe, Germany.
Trevor
T
Petney
Comparative Tropical Medicine and Parasitology, Ludwig-Maximilians-University Munich, Munich, Germany.
Cornelia
C
Silaghi
Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-University Munich, Munich, Germany.
Viktor
V
Dyachenko
IDEXX Vet Med Lab, Ludwigsburg, Germany.
Nikola
N
Pantchev
Institute for Infectious Diseases and Zoonoses, Ludwig-Maximilians-University Munich, Munich, Germany.
Reinhard K
RK
Straubinger
Laboratory at Zugersee, Hünenberg, Switzerland.
Daniel
D
Schaarschmidt-Kiener
Clinic for Swine and Small Ruminants, University of Veterinary Medicine Hannover, Hannover, Germany.
Martin
M
Ganter
Department of Ecology and Evolutionary Biology, Princeton University, Princeton, New Jersey, United States of America.
Matthew L
ML
Aardema
Institute of Medical Microbiology and Hygiene, University of Freiburg, Freiburg, Germany.
Friederike D
FD
von Loewenich
D041081:Anaplasma phagocytophilum / Q000235:genetics*; D000712:Anaplasmosis / Q000382:microbiology; D000818:Animals; D000829:Animals, Domestic / Q000382:microbiology; D016873:Ehrlichiosis / Q000382:microbiology; D006801:Humans; D058885:Multilocus Sequence Typing; D012336:RNA, Ribosomal, 16S / Q000235:genetics*
D012336:RNA, Ribosomal, 16S