RESEARCH ARTICLE
Urban rats as carriers of invasive Salmonella
Typhimurium sequence type 313, Kisangani,
Democratic Republic of Congo
Dadi Falay
1,2,3
, Liselotte Hardy
ID
3
*, Jacques Tanzito
4
, Octavie Lunguya
5,6
,
Edmonde Bonebe
5
, Marjan Peeters
3
, Wesley Mattheus
7
, Chris Van Geet
8
,
Erik Verheyen
9,10
, Dudu Akaibe
4
, Pionus Katuala
4
, Dauly Ngbonda
1
, Franc¸ ois-
Xavier Weill
11
, Maria Pardos de la Gandara
11
, Jan Jacobs
2,3
1 Department of Pediatrics, University Hospital of Kisangani, Kisangani, the Democratic Republic of the
Congo, 2 Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium,
3 Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium, 4 Biodiversity
Monitoring Center (Centre de Surveillance de la Biodiversite´ , CSB), Faculty of Science, University of
Kisangani, Kisangani, the Democratic Republic of the Congo, 5 Department of Medical Biology, National
Institute for Biomedical Research, Kinshasa, the Democratic Republic of the Congo, 6 Department of
Microbiology, University Teaching Hospital of Kinshasa, Kinshasa, Democratic Republic of the Congo,
7 Sciensano, Infectious Diseases in Humans, Bacterial Diseases, Brussels, Belgium, 8 Department of
Cardiovascular Sciences and Pediatrics, KU Leuven and University Hospital Leuven, Leuven, Belgium, 9 OD
Taxonomy & Phylogeny, Royal Belgian Institute of Natural Sciences, Brussels, Belgium, 10 Evolutionary
Ecology, University of Antwerp, Antwerp, Belgium, 11 Institut Pasteur, Universite´ Paris Cite´ , Unite´ des
bacte´ ries pathogènes ente´ riques, Paris, France
* lhardy@itg.be
Abstract
Background
Invasive non-typhoidal Salmonella (iNTS–mainly serotypes Enteritidis and Typhimurium)
are major causes of bloodstream infections in children in sub-Saharan Africa, but their reser-
voir remains unknown. We assessed iNTS carriage in rats in an urban setting endemic for
iNTS carriage and compared genetic profiles of iNTS from rats with those isolated from
humans.
Methodology/Principal findings
From April 2016 to December 2018, rats were trapped in five marketplaces and a slaughter-
house in Kisangani, Democratic Republic of the Congo. After euthanasia, blood, liver,
spleen, and rectal content were cultured for Salmonella. Genetic relatedness between iNTS
from rats and humans—obtained from blood cultures at Kisangani University Hospital—was
assessed with multilocus variable-number tandem repeat (VNTR) analysis (MLVA), multilo-
cus sequence typing (MLST) and core-genome MLST (cgMLST). 1650 live-capture traps
yielded 566 (34.3%) rats (95.6% Rattus norvegicus, 4.4% Rattus rattus); 46 (8.1%) of them
carried Salmonella, of which 13 had more than one serotype. The most common serotypes
were II.42:r:- (n = 18 rats), Kapemba (n = 12), Weltevreden and Typhimurium (n = 10, each),
and Dublin (n = 8). Salmonella Typhimurium belonged to MLST ST19 (n = 7 rats) and the
invasive ST313 (n = 3, isolated from deep organs but not from rectal content). Sixteen
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OPEN ACCESS
Citation: Falay D, Hardy L, Tanzito J, Lunguya O,
Bonebe E, Peeters M, et al. (2022) Urban rats as
carriers of invasive Salmonella Typhimurium
sequence type 313, Kisangani, Democratic
Republic of Congo. PLoS Negl Trop Dis 16(9):
e0010740. https://doi.org/10.1371/journal.
pntd.0010740
Editor: Travis J. Bourret, Creighton University,
UNITED STATES
Received: May 25, 2022
Accepted: August 13, 2022
Published: September 6, 2022
Peer Review History: PLOS recognizes the
benefits of transparency in the peer review
process; therefore, we enable the publication of
all of the content of peer review and author
responses alongside final, published articles. The
editorial history of this article is available here:
https://doi.org/10.1371/journal.pntd.0010740
Copyright: © 2022 Falay et al. This is an open
access article distributed under the terms of the
Creative Commons Attribution License, which
permits unrestricted use, distribution, and
reproduction in any medium, provided the original
author and source are credited.
Data Availability Statement: All relevant data are
within the manuscript and its Supporting
Information files. All genomes obtained by WGS