Dr James Gana
Lecturer/Veterinary Doctor
g.james@fuek.edu.ng
+2348038254950
Poultry and Veterinary unit, Agric Department
Academic Information
Faculty of Vocational and Technical Education
Agric
PhD (UP South Africa), MVSC (UI), PGDE (NOUN), DVM (UDUS)
Academics
Specialization & Research
Veterinary Medicine, Infectious diseases, Veterinary and Medical Microbiology, Public Health.
Professional Biography
Dr. James Gana is a Dedicated academic and Veterinary Medical Researcher, Specializing in Infectious Diseases and Public Health.
In his recent research, Prevalence risk factors and molecular characterization of Listeria species from cattle farms, beef abattoirs, and retail outlets in Gauteng, South Africa, He determined the prevalence and characteristics of Listeria species recovered from cattle farms, beef abattoirs, and retail outlets using phenotypic and molecular methods. The study first documented the occurrence of L. monocytogenes, L. innocua, and L. welshimeri on cattle farms and beef abattoirs in the country. He demonstrated a very high prevalence of antimicrobial resistance (AMR) in the Listeria species across the three levels of sampling. The study detected three pathogenic serogroups in L. monocytogenes recovered from beef and beef products, of which 82-100% were positive for virulence genes.
Whole-genome sequencing (WGS) was used for genomic characterization of 110 strains of Listeria innocua (L. innocua) isolated from 23 cattle farms, 8 beef abattoirs, and 48 retail outlets in Gauteng province, South Africa. The study detected 14 STs, 13 resistance genes, and 23 virulence genes. Of the 14 STs detected, ST637 (26.4%), ST448 (20%), 537 (13.6%), and 1085 (12.7%) were predominant, and the frequency varied significantly (P<0.05). All 110 isolates of L. innocua were carriers of one or more antimicrobial resistance genes, with resistance genes lin (100%), fosX (100%), and tet(M) (30%) being the most frequently detected (P<0.05). Of the 23 virulence genes recognized, 13 (clpC, clpE, clpP, hbp1.svpA, hbp2, iap/cwhA, lap, lpeA, lplA1, lspA, oatA, pdgA, and prsA2) were found in all 110 isolates of L. innocua. Overall, diversity and significant differences were detected in the frequencies of STs, resistance, and virulence genes according to the origins (source and sample type) of the L. innocua isolates. This, being the first genomic characterization of L. innocua recovered from the three levels/industries (farm, abattoir, and retail) of the beef production system in South Africa, provides data on the organism's distribution and potential food safety implications.
Overall, in 60 isolates of Listeria monocytogenes, there were seven STs, six CCs, forty-four putative virulence factors, two resistance genes, one plasmid with AMR genes, and three with conjugative genes, one CRISPR gene, and all 60 isolates were positive for proviruses/prophages. Among the seven STs detected, ST204 (46.7%) and ST2 (21.7%) were the most prominent, with ST frequency varying significantly (p < 0.001). The predominant CC detected were CC2 (21.7%) and CC204 (46.7%) in lineages I and II, respectively. Of the 44 virulence factors detected, 26 (across Listeria Pathogenicity Islands, LIPIs) were present in all the isolates. The difference in the detection frequency varied significantly (p < 0.001). The two AMR genes (fosX and vga(G)) detected were present in all 60 (100%) isolates of L. monocytogenes. The only plasmid, NF033156, was present in three (5%) isolates. A CRISPR-Cas system was detected in six (10%), and all the isolates carried proviruses/prophages. The source and sample type significantly affected the frequencies of STs and virulence factors in the isolates of L. monocytogenes. The presence of fosX and vga(G) genes in all L. monocytogenes isolates obtained from the three industries of the beef production chain can potentially cause therapeutic implications. Our study, which characterized L. monocytogenes recovered from the three levels in the beef production chain, is the first time genomics was performed on this type of data set in the country, and this provides insights into the health implications of Listeria
The whole-genome sequencing (WGS) was also used to characterize 12 isolates of L. welshimeri recovered from the beef production chain in Gauteng province, South Africa. Two sequence types (STs) were identified, with ST3294 accounting for 75% (9/12) and ST1084 for 16.7% (2/12) of the isolates. Antimicrobial resistance (AMR) plasmids detected included conjugative plasmid (MOBP2; T_virB11; virb4) in 58.3% and AMR plasmid (NFO33156) in 41.7% of the isolates. Two AMR genes, fosX (25%) and vga (G) (100%), along with 11 virulence factors, were present in all 12 isolates of L. welshimeri. The phylogenomic tree of L. welshimeri clustering based on the ST according to the source, type, and class of beef and beef products revealed three groups: ST3294 (n=9), ST1084 (n=2), and unassigned ST (n=1). The findings of this study demonstrate the potential for transferring genetic materials from non-pathogenic L. welshimeri to pathogenic L. monocytogenes within the same ecological niche.
The use of multiple-locus variable-number analysis (MLVA) of tandem repeats (TRs) for subtyping Listeria monocytogenes .It has proven to be reliable and fast. The study determined the MLVA genotypes of 60 isolates of L. monocytogenes recovered from cattle farms, abattoirs, and retail outlets in Gauteng province, South Africa. The distribution of the 60 L. monocytogenes isolates analyzed by type of sample was as follows: raw beef (28, 46.7%), ready-to-eat beef products (9, 15.0%), beef carcass swabs (9, 15.0%), cattle environment (6, 10.0%), and cattle feces (8, 13.3%). The serogroups of the isolates were determined using PCR and the MLVA genotypes based on six selected loci. The frequency of the 60 serogroups detected was as follows: 1/2a-3a (IIa) (27, 45.0%); 4b-4d-4e (1Vb) (24, 40.0%); 1/2c-3c (IIc) (8, 13.3%); and 1/2b-3b (IIb) (1, 1.7%). MLVA successfully clustered genetically related isolates and differentiated nonrelated isolates, irrespective of their sources, sample types, and serogroups, as demonstrated by 16 MLVA pattern types detected. For serogroup 4b-4d-4e (IVb), there was no variation in TRs LM-TR2, LM-TR4, and LM-TR6, which each contained only one allele (02, 00, and 93, respectively). However, across the sources and sample types of isolates, there was variation in serogroup 4b-4d-4e (IVb): LM-TR1 contained 00, 03, and 05; LMTR3 contained 14, 20, and 22; and LM-TR5 contained 14, 21, and 25. Similar patterns of variation in the TRs were detected in the other serogroups (1/2a-3a, 1/2b-3b, and 1/2c-3c). BioNumeric data analysis identified at least five types in Gauteng province. MLVA epidemiologically clustered the related isolates and differentiated unrelated isolates.
The data demonstrate that the consumption of Listeria-contaminated beef products still poses a health risk of listeriosis in the country.
Published Works
Scopus ID: 57865466300
ORCID: https://orcid.org/0000-0001-9415-5297
Google Scholar: Gana James; James Gana Google Scholar.
Web of Science Researcher ID: QVG-5089-2026
PubMe: https://pubmed.ncbi.nlm.nih.gov/?term=Gana+james+
In his recent research, Prevalence risk factors and molecular characterization of Listeria species from cattle farms, beef abattoirs, and retail outlets in Gauteng, South Africa, He determined the prevalence and characteristics of Listeria species recovered from cattle farms, beef abattoirs, and retail outlets using phenotypic and molecular methods. The study first documented the occurrence of L. monocytogenes, L. innocua, and L. welshimeri on cattle farms and beef abattoirs in the country. He demonstrated a very high prevalence of antimicrobial resistance (AMR) in the Listeria species across the three levels of sampling. The study detected three pathogenic serogroups in L. monocytogenes recovered from beef and beef products, of which 82-100% were positive for virulence genes.
Whole-genome sequencing (WGS) was used for genomic characterization of 110 strains of Listeria innocua (L. innocua) isolated from 23 cattle farms, 8 beef abattoirs, and 48 retail outlets in Gauteng province, South Africa. The study detected 14 STs, 13 resistance genes, and 23 virulence genes. Of the 14 STs detected, ST637 (26.4%), ST448 (20%), 537 (13.6%), and 1085 (12.7%) were predominant, and the frequency varied significantly (P<0.05). All 110 isolates of L. innocua were carriers of one or more antimicrobial resistance genes, with resistance genes lin (100%), fosX (100%), and tet(M) (30%) being the most frequently detected (P<0.05). Of the 23 virulence genes recognized, 13 (clpC, clpE, clpP, hbp1.svpA, hbp2, iap/cwhA, lap, lpeA, lplA1, lspA, oatA, pdgA, and prsA2) were found in all 110 isolates of L. innocua. Overall, diversity and significant differences were detected in the frequencies of STs, resistance, and virulence genes according to the origins (source and sample type) of the L. innocua isolates. This, being the first genomic characterization of L. innocua recovered from the three levels/industries (farm, abattoir, and retail) of the beef production system in South Africa, provides data on the organism's distribution and potential food safety implications.
Overall, in 60 isolates of Listeria monocytogenes, there were seven STs, six CCs, forty-four putative virulence factors, two resistance genes, one plasmid with AMR genes, and three with conjugative genes, one CRISPR gene, and all 60 isolates were positive for proviruses/prophages. Among the seven STs detected, ST204 (46.7%) and ST2 (21.7%) were the most prominent, with ST frequency varying significantly (p < 0.001). The predominant CC detected were CC2 (21.7%) and CC204 (46.7%) in lineages I and II, respectively. Of the 44 virulence factors detected, 26 (across Listeria Pathogenicity Islands, LIPIs) were present in all the isolates. The difference in the detection frequency varied significantly (p < 0.001). The two AMR genes (fosX and vga(G)) detected were present in all 60 (100%) isolates of L. monocytogenes. The only plasmid, NF033156, was present in three (5%) isolates. A CRISPR-Cas system was detected in six (10%), and all the isolates carried proviruses/prophages. The source and sample type significantly affected the frequencies of STs and virulence factors in the isolates of L. monocytogenes. The presence of fosX and vga(G) genes in all L. monocytogenes isolates obtained from the three industries of the beef production chain can potentially cause therapeutic implications. Our study, which characterized L. monocytogenes recovered from the three levels in the beef production chain, is the first time genomics was performed on this type of data set in the country, and this provides insights into the health implications of Listeria
The whole-genome sequencing (WGS) was also used to characterize 12 isolates of L. welshimeri recovered from the beef production chain in Gauteng province, South Africa. Two sequence types (STs) were identified, with ST3294 accounting for 75% (9/12) and ST1084 for 16.7% (2/12) of the isolates. Antimicrobial resistance (AMR) plasmids detected included conjugative plasmid (MOBP2; T_virB11; virb4) in 58.3% and AMR plasmid (NFO33156) in 41.7% of the isolates. Two AMR genes, fosX (25%) and vga (G) (100%), along with 11 virulence factors, were present in all 12 isolates of L. welshimeri. The phylogenomic tree of L. welshimeri clustering based on the ST according to the source, type, and class of beef and beef products revealed three groups: ST3294 (n=9), ST1084 (n=2), and unassigned ST (n=1). The findings of this study demonstrate the potential for transferring genetic materials from non-pathogenic L. welshimeri to pathogenic L. monocytogenes within the same ecological niche.
The use of multiple-locus variable-number analysis (MLVA) of tandem repeats (TRs) for subtyping Listeria monocytogenes .It has proven to be reliable and fast. The study determined the MLVA genotypes of 60 isolates of L. monocytogenes recovered from cattle farms, abattoirs, and retail outlets in Gauteng province, South Africa. The distribution of the 60 L. monocytogenes isolates analyzed by type of sample was as follows: raw beef (28, 46.7%), ready-to-eat beef products (9, 15.0%), beef carcass swabs (9, 15.0%), cattle environment (6, 10.0%), and cattle feces (8, 13.3%). The serogroups of the isolates were determined using PCR and the MLVA genotypes based on six selected loci. The frequency of the 60 serogroups detected was as follows: 1/2a-3a (IIa) (27, 45.0%); 4b-4d-4e (1Vb) (24, 40.0%); 1/2c-3c (IIc) (8, 13.3%); and 1/2b-3b (IIb) (1, 1.7%). MLVA successfully clustered genetically related isolates and differentiated nonrelated isolates, irrespective of their sources, sample types, and serogroups, as demonstrated by 16 MLVA pattern types detected. For serogroup 4b-4d-4e (IVb), there was no variation in TRs LM-TR2, LM-TR4, and LM-TR6, which each contained only one allele (02, 00, and 93, respectively). However, across the sources and sample types of isolates, there was variation in serogroup 4b-4d-4e (IVb): LM-TR1 contained 00, 03, and 05; LMTR3 contained 14, 20, and 22; and LM-TR5 contained 14, 21, and 25. Similar patterns of variation in the TRs were detected in the other serogroups (1/2a-3a, 1/2b-3b, and 1/2c-3c). BioNumeric data analysis identified at least five types in Gauteng province. MLVA epidemiologically clustered the related isolates and differentiated unrelated isolates.
The data demonstrate that the consumption of Listeria-contaminated beef products still poses a health risk of listeriosis in the country.
Published Works
Scopus ID: 57865466300
ORCID: https://orcid.org/0000-0001-9415-5297
Google Scholar: Gana James; James Gana Google Scholar.
Web of Science Researcher ID: QVG-5089-2026
PubMe: https://pubmed.ncbi.nlm.nih.gov/?term=Gana+james+