Metagenomic Sequencing of Wastewater from a South African
Research Farm
Briallen Lobb,
a
Anthony A. Adegoke,
b
Kesen Ma,
a
Andrew C. Doxey,
a
Olayinka A. Aiyegoro
a,c
a
Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
b
Department of Microbiology, Faculty of Science, University of Uyo, Uyo, Akwa Ibom State, Nigeria
c
GI Microbiology and Biotechnology Section, Agricultural Research Council–Animal Production, Irene, South
Africa
ABSTRACT We sequenced wastewater effluent from the Agricultural Research
Council–Animal Production in South Africa that conducts studies on livestock health
and farm ecology. Thauera, Oscillibacter, and Pseudomonas were the most abundant
genera within the community. Thirty-one different antibiotic resistance genes were
identified, 10 of which are associated with tetracycline resistance.
A
ntibiotics are used to promote growth and manage disease in livestock at Agri-
cultural Research Council–Animal Production in South Africa. However, the spread
of antibiotic resistance is a pervasive concern. Waste from farm animals has been shown
to spread antibiotic-resistant bacteria, sometimes due to selective pressure found in
antibiotic-dosed livestock (1–3). One of a farm’s effluents, wastewater, is a documented
reservoir of antibiotic resistance genes that could transfer to human pathogens (4–6).
Wastewater is also known to contain animal pathogens, some of which are opportu-
nistic and can spread zoonoses (7, 8). Sequencing of the wastewater microbiome can
help identify pathogenic species that might exist on the institute’s farm and detect
antibiotic resistance genes that may be active in these microbial communities.
The metagenome was created from expended water taken from Agricultural Re-
search Council–Animal Production (ARC-AP) in Irene, South Africa. A 1-liter composite
sample was created by combining five 200-ml samples collected from different waste-
water gutters in the pig facility. The composite sample was centrifuged at 3,500 rpm for
10 min at room temperature to separate the biomass and water. The water was filtered
to trap microbes, and DNA was extracted from the pellet on the filter paper. The DNA
extraction was done using the FastDNA Spin kit for water (MP Biomedicals, Solon, OH,
USA) and the FastPrep apparatus, according to the instructions given by the manufac-
turer. The DNA was sequenced with the Illumina HiSeq platform and the Illumina HiSeq
reagent v3. A total of 28,540,348 read pairs with an average read length of 119 bp each
were generated. The reads were trimmed with Sickle version 1.33 (9) and Trim Galore!
version 0.5.0 (10) and then assembled using MEGAHIT version 1.1.2 (11), resulting in
58,129 contigs longer than 1 kb. The total assembly length was 311,492,658 bp, with an
N
50
value of 861 bp. Prodigal version 2.6.3 with the -p meta option (12) was used next,
facilitating the prediction of 612,922 coding sequences.
A profile of the community based on taxonomic marker genes was constructed with
MetAnnotate using the usearch option (13). An abundance for each marker gene hit
was calculated using Bowtie 2 version 2.3.4.2 (14), SAMtools version 1.9 (15), and
BEDtools version 2.27.1 (16). The abundance of each gene was calculated as the
average coverage per base pair across the coding sequence. The most common genera
present (based on the average abundance across all taxonomic markers) are Thauera
(19%), Oscillibacter (7%), Pseudomonas (6%), Prevotella (5%), and Bacteroides (3%).
A blastp search of the homolog models in the Comprehensive Antibiotic Resistance
Received 25 September 2018 Accepted 28
September 2018 Published 25 October 2018
Citation Lobb B, Adegoke AA, Ma K, Doxey AC,
Aiyegoro OA. 2018. Metagenomic sequencing
of wastewater from a South African research
farm. Microbiol Resour Announc 7:e01323-18.
https://doi.org/10.1128/MRA.01323-18.
Editor Christina A. Cuomo, Broad Institute of
MIT and Harvard
Copyright © 2018 Lobb et al. This is an open-
access article distributed under the terms of the
Creative Commons Attribution 4.0 International
license.
Address correspondence to Olayinka A.
Aiyegoro, olayinka.aiyegoro@uwaterloo.ca.
GENOME SEQUENCES
crossm
Volume 7 Issue 16 e01323-18 mra.asm.org 1