PREVALENCE OF LISTERIA AND VIBRIO SPECIES AND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) INBIVALVES(Ergeria radiata) FROM BAYELSA STATE, NIGERIA
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The consumption of bivalves, such as mussels, clams, and oysters, is widespread across the globe, particularly in Coastal regions. Due to the natural habitat of bivalves and feeding habitat, there is a high possibility of the meat being contaminated with microorganisms and toxic elements. Hence, this research investigated the prevalence of Listeria and Vibriospecies, and polycyclic aromatic hydrocarbons (PAHs) in bivalves (Ergeria radiata). A total of three hundred (300) edible bivalves (Ergeria radiata) were obtained during March 2023 to February 2024 from the Ekowe community Coastal waters and from wet markets (Swali
and Opolo) using sterile containers. Bacteria were enumerated using standard microbiological procedures. Isolates of Vibrio and Listeria were identified by the polymerase chain reaction (PCR) technique. Antibiotic susceptibility of the isolates was determinedusingKirby-Bauer disc diffusion method. Plasmid profiling and curing of Vibrio and Listeria isolates were determined by standard methods. Proximate analysis of Ergeriaradiata was determined using standard analytical chemical methods. Mineral and heavy metal compositions were determined by Atomic Absorption Spectroscopy (AAS), while Na and K were analyzed by flame photometry. Polycyclic aromatic hydrocarbons were analyzed by Gas Chromatography-Mass Spectrometry (GC/MS). Standard methods were used to determine the physicochemical properties of the Coastal water samples. The data obtained were statistically analyzed using one-way analysis of variance (ANOVA) using SPSS version 20.0. Duncan multiple range test was used to separate the means at p<0.05 significant differences. The results of this study revealed that higher bacterial counts were observed in thewet season compared to the dry season. The total heterotrophic bacterial counts for the wet season ranged from 20.48 ± 1.62x 10 5 cfu/g - 30.06 ± 1.63x 10 5 cfu/g, while for dry season it rangedfrom 10.88 ± 1.09 x 105 cfu/g – 18.18 ± 1.10 x10
5 cfu/g. The Vibrio counts for wet seasonranged from 16.82 ± 1.17 x 10 5 cfu/g - 19.90 ± 1.27 x 10 5 cfu/, while for dry season it rangedfrom 9.96 ± 0.95 x 10 5 cfu/g – 13.58 ± 1.12 x 10
5 cfu/g. Listeria counts for wet seasonranged from 8 .08 ± 0.50 x 10 5 cfu/g – 11.52 ± 0.76 x 10 5 cfu/g, while for dry seasonit
ranged from 6.12 ± 0.67 x10 5 cfu/g – 9.72 ± 0.8 x 10 5 cfu/g - 9.72 ± 0.81 x 10 5 cfu/g.TheVibrio species isolated were Vibrio parahaemolyticus, Vibrio cholerae, Vibrio vulnificus, and Vibrio fluvialis with the accession numbers PP832852, PP382853, PP832854 and PP832855, respectively. Listeria species isolated were Listeria innocua PP832856, Listeria monocytogenes PP832857, and Listeria ivanovii PP328560. The hlyA virulence gene was detected in all the Listeria species for both wet and dry season. The virulence gene ctxAwasnot detected in Vibrio parahaemolyticus for wet season, but was detected in dry season. Thepenicillin binding protein (pbp2b) resistant gene was detected in all Listeria species. Theaph(2")-If antimicrobial resistant gene was detected in Vibrio parahaemolyticus andVibrofluvialis for wet season, while in dry season, it was detected in all the Vibrio species. Therewas no seasonal variation in the values obtained for proximate composition, minerals. andheavy metal content. Protein ranged from 7.42 ± 0.72 % - 7.59 ± 0.6 %, fat (0.74 ±0.05%-0.77± 0.9%), K (510 ± 0.52 mg/kg - 520 ± 0.13 mg/kg), and Pb (0.03 ± 0.01 mg/kg –0.047±0.16 mg/kg). Polycyclic aromatic hydrocarbons (PAHs) concentration of Ergeria sradiatawas low for both wet and dry season, and was below the permissible limit of 200 ppmset byWorld Health Organization (WHO). The physicochemical properties of the Coastal watersforwet season exceeded the permissible limit set by WHO. Bivalve (Ergeria radiata), although nutritionally rich, harbors potentially pathogenic bacteria of public health concern, particularly when they are consumed raw or not properly cooked.
and Opolo) using sterile containers. Bacteria were enumerated using standard microbiological procedures. Isolates of Vibrio and Listeria were identified by the polymerase chain reaction (PCR) technique. Antibiotic susceptibility of the isolates was determinedusingKirby-Bauer disc diffusion method. Plasmid profiling and curing of Vibrio and Listeria isolates were determined by standard methods. Proximate analysis of Ergeriaradiata was determined using standard analytical chemical methods. Mineral and heavy metal compositions were determined by Atomic Absorption Spectroscopy (AAS), while Na and K were analyzed by flame photometry. Polycyclic aromatic hydrocarbons were analyzed by Gas Chromatography-Mass Spectrometry (GC/MS). Standard methods were used to determine the physicochemical properties of the Coastal water samples. The data obtained were statistically analyzed using one-way analysis of variance (ANOVA) using SPSS version 20.0. Duncan multiple range test was used to separate the means at p<0.05 significant differences. The results of this study revealed that higher bacterial counts were observed in thewet season compared to the dry season. The total heterotrophic bacterial counts for the wet season ranged from 20.48 ± 1.62x 10 5 cfu/g - 30.06 ± 1.63x 10 5 cfu/g, while for dry season it rangedfrom 10.88 ± 1.09 x 105 cfu/g – 18.18 ± 1.10 x10
5 cfu/g. The Vibrio counts for wet seasonranged from 16.82 ± 1.17 x 10 5 cfu/g - 19.90 ± 1.27 x 10 5 cfu/, while for dry season it rangedfrom 9.96 ± 0.95 x 10 5 cfu/g – 13.58 ± 1.12 x 10
5 cfu/g. Listeria counts for wet seasonranged from 8 .08 ± 0.50 x 10 5 cfu/g – 11.52 ± 0.76 x 10 5 cfu/g, while for dry seasonit
ranged from 6.12 ± 0.67 x10 5 cfu/g – 9.72 ± 0.8 x 10 5 cfu/g - 9.72 ± 0.81 x 10 5 cfu/g.TheVibrio species isolated were Vibrio parahaemolyticus, Vibrio cholerae, Vibrio vulnificus, and Vibrio fluvialis with the accession numbers PP832852, PP382853, PP832854 and PP832855, respectively. Listeria species isolated were Listeria innocua PP832856, Listeria monocytogenes PP832857, and Listeria ivanovii PP328560. The hlyA virulence gene was detected in all the Listeria species for both wet and dry season. The virulence gene ctxAwasnot detected in Vibrio parahaemolyticus for wet season, but was detected in dry season. Thepenicillin binding protein (pbp2b) resistant gene was detected in all Listeria species. Theaph(2")-If antimicrobial resistant gene was detected in Vibrio parahaemolyticus andVibrofluvialis for wet season, while in dry season, it was detected in all the Vibrio species. Therewas no seasonal variation in the values obtained for proximate composition, minerals. andheavy metal content. Protein ranged from 7.42 ± 0.72 % - 7.59 ± 0.6 %, fat (0.74 ±0.05%-0.77± 0.9%), K (510 ± 0.52 mg/kg - 520 ± 0.13 mg/kg), and Pb (0.03 ± 0.01 mg/kg –0.047±0.16 mg/kg). Polycyclic aromatic hydrocarbons (PAHs) concentration of Ergeria sradiatawas low for both wet and dry season, and was below the permissible limit of 200 ppmset byWorld Health Organization (WHO). The physicochemical properties of the Coastal watersforwet season exceeded the permissible limit set by WHO. Bivalve (Ergeria radiata), although nutritionally rich, harbors potentially pathogenic bacteria of public health concern, particularly when they are consumed raw or not properly cooked.
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