Biosciences Nairobi – Spread of tetracycline
resistance gene tetM via TN916-like elements in
East African camel GBS
Unlocking livestock development potential through science, influence and capacity development
ILRI APM, Addis Ababa, 15-17 May 2013
This document is licensed for use under a Crea3ve Commons A6ribu3on‐Noncommercial‐Share Alike 3.0 Unported License May 2013
Anne Liljander1$, Anne Fischer1,2$*, Heike Kaspar3, Cecilia Muriuki1, Hans-Henrik Fuxelius4, Erik Bongcam-Rudloff4, Etienne P. de Villiers5, Charlotte A.
Huber6, Joachim Frey7, Claudia Daubenberger6, Richard Bishop1, Mario Younan8 and Joerg Jores1
2012 retreat
Abstract: Camels are the most valuable livestock species in the Horn of Africa and play a pivotal role for nutrition for millions of people.
Streptococcus agalactiae (GBS) has been isolated from mastitis, wound infections and asymptomatic camels. We present the first
molecular epidemiological study based on genetic and phenotypic data from camel derived GBS isolated in the Horn of Africa. Ninety-two
GBS were characterized using multilocus sequence typing, capsular polysaccharide typing and antimicrobial resistance testing. We
investigated the GBS using Bayesian linkage, phylogenetic and minimum spanning tree analyses and compared them with human GBS
from East Africa in order to evaluate genetic exchange between GBS populations in the region. Camel GBS associated sequence types
were distinct from human and bovine GBS reported so far. We mapped specific sequence types and serotypes to major disease
complexes caused by GBS. Widespread resistance (34%) to tetracycline was associated with multiple acquisitions of the tetM gene,
primarily among isolates associated with mastitis. Wound infections and mastitis in camels associated with GBS are widespread and
should be treated with antimicrobials other than tetracycline in East Africa. The resistance patterns of major livestock pathogens in the
Horn of Africa need to be monitored in order to prevent the emergence of resistance to selected antimicrobials available in the region.
1International Livestock Research Institute, Nairobi, Kenya
2Molecular Biology and Biotechnology Department, International Centre of Insect Physiology and Ecology, Nairobi, Kenya
3Federal Office of Consumer Protection and Food Safety (BVL), Berlin, Germany
4SLU-Global Bioinformatics Centre, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
6Department of Medical Parasitology and Infection Biology, Swiss TPH, Basel, Switzerland
7Institute of Veterinary Bacteriology, University of Bern, Bern, Switzerland
8Vétérinaires Sans Frontières Germany, Nairobi, Kenya
ST4
ST3
ST1
ST2
ST17
ST182
ST26
0.0020
ST28
ST19
ST484
ST609
ST614
ST24
ST23
ST492
ST501
ST616
ST611
ST617
ST615
ST610 ST612
ST618ST613
ST12
ST10
ST8
ST486
ST103
ST485
ST328
ST327
100
99 99
100
99
97
91
100
!"#$%&'(
!"#$%&
!"#$%'
!"#$%(
!"#$%)
!"#$%*
!"#$%+
!"#$%%
!"#$%$
!"#$),
!"#$%-
!"#$%&
!"#$%'
!"#$%(
!"#$%)
!"#$%*
!"#$%+
!"#$%%
!"#$%$
!"#$),
!"#$%-
!"#$%&
!"#$%'
!"#$%(
!"#$%)
!"#$%*
!"#$%+
!"#$%%
!"#$%$
!"#$),
!"#$%-
!"#$%&
!"#$%'
!"#$%(
!"#$%)
!"#$%*
!"#$%+
!"#$%%
!"#$%$
!"#$),
!"#$%- Wound infection/ abscess
No data
Gingivitis
Vaginal discharge
Mastitis
Chronic cough
Population 2
Population 3
Tetracycline resistance
>64 µg/ml
Tetracycline resistance
>32 µg/ml
Susceptable to
tetracycline
6 alleles in common 5 alleles in common 2 alleles in common
Serotype V
Serotype VI
Serotype Ia
Serotype II
Serotype III
! "#$
Not tested
Population 1
Healthy
!"#$!"%
!"&
!"'
!"(
%
(
"#
")
*(&
"+
)(
"#%
"()
%)'
%)(
*(!
!"! )!
!#+
!"*
*
)%
)*
*+)
&#"
"'
*(*
"
)
,-./-01-2345-
67'
67(
Figure 1: Minimum spanning tree (MSTree) of East African isolates of camel S. agalac(ae
Each circle represents a single sequence type (ST), its size is propor9onal to the number of isolates.
The topological organiza9on within the MSTree is based on a graphical algorithm using an itera9ve
network approach to iden9fy sequen9al links of increasing distance.
A) Clonal complex, B) capsular serotype, C) resistance to tetracycline, and D) clinical symptoms.
Figure 3: Unrooted phylogene3c tree displaying the phylogene3c
rela3onship of the East African camel and human S. agalac(ae isolates.
Camel STs are displayed in red. The bootstrap values above 90 are displayed.
Figure 2: Popula3on structure and phylogene3c rela3onship of 92 East African camel GBS
and 169 Kenyan human GBS The popula9ons revealed by the STRUCTURE analysis using the
linkage model and sequences from 7 house‐keeping gene fragments are displayed below the
figure and marked with different colours, the hosts are displayed above. The ancestral parts
of each isolate are displayed in ver9cal lines. The STs and capsular serotypes are displayed for
every popula9on.