Biology subjects

Matle, I.

Publications and source records attributed to Matle, I..

3 recordsLinked to original sources

bioRxiv2023

Genus-Wide Genomic Characterization of Macrococcus: Insights into Evolution, Population Structure, and Functional Potential

Macrococcus species have been isolated from a range of mammals and mammal-derived food products. While they are largely considered to be animal commensals, Macrococcus spp. can be opportunistic pathogens in both veterinary and human clinical settings. This study aimed to provide insight into the evolution, population structure, and functional potential of the Macrococcus genus, with an emphasis on antimicrobial resistance (AMR) and virulence potential. All high-quality, publicly available Macrococcus genomes (n = 104, accessed 27 August 2022), plus six South African genomes sequenced here (two strains from bovine clinical mastitis cases and four strains from beef products), underwent taxonomic assignment (using four different approaches), AMR determinant detection (via AMRFinderPlus), and virulence factor detection (using DIAMOND and the core Virulence Factor Database). Overall, the 110 Macrococcus genomes were of animal commensal, veterinary clinical, food-associated (including food spoilage), and environmental origins; five genomes (4.5%) originated from human clinical cases. Notably, none of the taxonomic assignment methods produced identical results, highlighting the potential for Macrococcus species misidentifications. The most common predicted antimicrobial classes associated with AMR determinants identified across Macrococcus included macrolides, beta-lactams, and aminoglycosides (n = 81, 61, and 44 of 110 genomes; 73.6, 55.5, and 40.0%, respectively). Genes showing homology to Staphylococcus aureus exoenzyme aureolysin were detected across multiple species (using 90% coverage, n = 40 and 77 genomes harboring aureolysin-like genes at 60% and 40% amino acid [AA] identity, respectively). Staphylococcus aureus Panton-Valentine leucocidin toxin-associated lukF-PV and lukS-PV homologs were identified in eight M. canis genomes ([≥]40% AA identity, >85% coverage). Using a method that delineates populations using recent gene flow (PopCOGenT), two species (M. caseolyticus and M. armenti) were composed of multiple within-species populations. Notably, M. armenti was partitioned into two populations, which differed in functional potential (e.g., one harbored beta-lactamase family, type II toxin-antitoxin system, and stress response proteins, while the other possessed a Type VII secretion system; PopCOGenT P < 0.05). Overall, this study leverages all publicly available Macrococcus genomes in addition to newly sequenced genomes from South Africa to identify genomic elements associated with AMR or virulence potential, which can be queried in future experiments.

microbiology↗

bioRxiv2022

Genomic surveillance of Bacillus cereus sensu lato strains isolated from meat and poultry products in South Africa enables inter- and intra-national surveillance and source tracking

Members of the Bacillus cereus sensu lato (s.l.) species complex, also known as the B. cereus group, vary in their ability to cause illness, but are frequently isolated from foods, including meat products; however, food safety surveillance efforts that employ whole-genome sequencing (WGS) often neglect these potential pathogens. Here, WGS was used to characterize B. cereus s.l. strains (n = 25) isolated during surveillance of meat products in South Africa. Strains were collected from beef, poultry, and mixed meat products obtained from (i) retail outlets, processing plants, and butcheries across six South African provinces (n = 15, 7, and 1, respectively), and (ii) imports in cold stores (n = 2). Strains were assigned to panC Groups IV, III, II, and V (n = 18, 5, 1, and 1, respectively) and spanned multiple genomospecies, regardless of the taxonomy used. All strains possessed diarrheal toxin-encoding genes, while one sequence type 26 (ST26) strain possessed cereulide (emetic toxin) synthetase-encoding genes. No strains harbored anthrax toxin- or capsule-encoding genes. The 25 strains were partitioned into 15 lineages via in silico seven-gene multi-locus sequence typing (MLST), six of which contained multiple strains sequenced in this study, which were identical or nearly identical at the whole-genome scale. Five MLST lineages contained (nearly) identical genomes collected from two or three South African provinces; one MLST lineage contained nearly identical genomes from two countries (South Africa and the Netherlands), indicating that B. cereus s.l. can spread intra- and inter-nationally via foodstuffs. ImportanceNation-wide foodborne pathogen surveillance programs that employ high-resolution genomic methods have been shown to provide vast public health and economic benefits. However, B. cereus s.l. are often overlooked during large-scale, routine WGS efforts. Thus, to our knowledge, no studies to date have evaluated the potential utility of WGS for B. cereus s.l. surveillance and source tracking in foodstuffs. In this proof-of-concept study, we applied WGS to B. cereus s.l. strains collected via South Africas national surveillance program of domestic and imported meat products, and we provide strong evidence that B. cereus s.l. can be disseminated intra- and inter-nationally via the agro-food supply chain. Our results showcase that WGS can be used for source tracking of B. cereus s.l. in foods, although future WGS and isolate metadata collection efforts are needed to ensure that B. cereus s.l. surveillance initiatives are on par with those of other foodborne pathogens.

microbiology↗

bioRxiv2021

Genomic characterization of endemic and ecdemic non-typhoidal Salmonella enterica lineages circulating among animals and animal products in South Africa

Non-typhoidal Salmonella enterica imposes a significant burden on human and animal health in South Africa. However, very little is known about lineages circulating among animals and animal products in the country on a genomic scale. Here, we used whole-genome sequencing (WGS) to characterize 63 Salmonella enterica strains (n = 18, 8, 13, and 24 strains assigned to serotypes Dublin, Hadar, Enteritidis, and Typhimurium, respectively) isolated from livestock, companion animals, wildlife, and animal products in South Africa over a 60-year period. Within-serotype phylogenies were constructed using genomes sequenced in this study, as well as publicly available genomes representative of each respective serotypes (i) global (n = 2,802 and 1,569 S. Dublin and Hadar genomes, respectively) and (ii) African (n = 716 and 343 S. Enteritidis and Typhimurium genomes, respectively) population. For S. Dublin, the approaches used here identified a largely antimicrobial-susceptible, endemic lineage circulating among humans, animals, and food in South Africa, as well as a lineage that was likely recently introduced from the United States. For S. Hadar, multiple South African lineages harboring streptomycin and tetracycline resistance-conferring genes were identified. African S. Enteritidis could be primarily partitioned into one largely antimicrobial-susceptible and one largely multidrug-resistant (MDR) clade, with South African isolates confined to the largely antimicrobial-susceptible clade. S. Typhimurium strains sequenced here were distributed across the African S. Typhimurium phylogeny, representing a diverse range of lineages, including numerous MDR lineages. Overall, this study provides insight into the evolution, population structure, and antimicrobial resistome composition of Salmonella enterica in Africa. IMPORTANCEGlobally, Salmonella enterica is estimated to be responsible for more than 93 million illnesses and 150,000 deaths annually. In Africa, the burden of salmonellosis is disproportionally high; however, WGS efforts are overwhelmingly concentrated in world regions with lower salmonellosis burdens. While WGS is being increasingly employed in South Africa to characterize Salmonella enterica, the bulk of these efforts have centered on characterizing human clinical strains. WGS data derived from non-typhoidal Salmonella enterica serotypes isolated from non-human sources in South Africa is extremely limited. To our knowledge, the genomes sequenced here represent the largest collection of non-typhoidal Salmonella enterica isolate genomes from non-human sources in South Africa to date. Furthermore, this study provides critical insights into endemic and ecdemic non-typhoidal Salmonella enterica lineages circulating among animals, foods, and humans in South Africa and showcases the utility of WGS in characterizing animal-associated strains from a world region with a high salmonellosis burden.

microbiology↗