title: Microbiological Quality and Prevalence of β-Lactam Antibiotic Resistance Genes in Oysters ( Crassostrea rhizophorae ).
abstract: The microbiological quality of oysters reflects the microbiological quality of their habitats because they are filter feeders. The objective of this study was to assess the bacterial composition of the edible oyster Crassostrea rhizophorae in urban and preserved estuaries. Particularly, we assessed the presence of pathogenic bacteria, investigated antibiotic susceptibility in bacterial isolates, and quantified β-lactam antibiotic resistance genes (blaTEM, blaSHV, and blaKPC) via quantitative PCR of oyster DNA. Our results detected total coliforms, Escherichia coli , and enterobacteria in the oysters from urban estuaries, which is indicative of poor water quality. In addition, our detection of the eaeA and stxA2 virulence genes in 16.7% of E. coli isolates from oysters from this region suggests the presence of multiantibiotic-resistant enteropathogenic and enterohemorrhagic E. coli strains. During periods of low precipitation, increased contamination by E. coli (in winter) and Vibrio parahaemolyticus (in autumn) was observed. In contrast, cultivated oysters inhabiting monitored farms in preserved areas had low levels of bacterial contamination, emphasizing that oyster culture monitoring enhances food quality and makes oysters fit for human consumption. Distinct antibiotic resistance profiles were observed in bacteria isolated from oysters collected from different areas, including resistance to β-lactam antibiotics. The presence of the blaTEMgene in 91.3% of oyster samples indicated that microorganisms in estuarine water conferred the capability to produce β-lactamase. To our knowledge, this is the first study to directly quantify and detect β-lactam antibiotic resistance genes in oysters. We believe our study provides baseline data for bacterial dynamics in estuarine oysters; such knowledge contributes to developing risk assessments to determine the associated hazards and consequences of consuming oysters from aquatic environments containing pathogenic bacteria that may possess antibiotic resistance genes.
authors.affiliation: Graduation Program in Animal Science, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Maria Aparecida da RessurreiÇão
authors.initials: MA
authors.lastname: Brandão
authors.affiliation: Graduation Program in Animal Science, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Amanda Teixeira Sampaio
authors.initials: AT
authors.lastname: Lopes
authors.affiliation: Graduation Program in Animal Science, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Maria Tereza da Silva
authors.initials: MT
authors.lastname: Neta
authors.affiliation: Graduation Program in Genetics and Molecular Biology, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Rhyan Barros Farias
authors.initials: RB
authors.lastname: de Oliveira
authors.affiliation: Graduation Program in Genetics and Molecular Biology, Santa Cruz State University, Ilhéus, Bahia, Brazil.|Department of Biological Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Rachel Passos
authors.initials: RP
authors.lastname: Rezende
authors.affiliation: Graduation Program in Animal Science, Santa Cruz State University, Ilhéus, Bahia, Brazil.|Department of Agricultural and Environmental Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: George Rêgo
authors.initials: GR
authors.lastname: Albuquerque
authors.affiliation: Enterobacteria Laboratory, Oswaldo Cruz Institute, Rio de Janeiro, Brazil.
authors.forename: Verônica Dias
authors.initials: VD
authors.lastname: Gonçalves
authors.affiliation: Enterobacteria Laboratory, Oswaldo Cruz Institute, Rio de Janeiro, Brazil.
authors.forename: Dália Dos Prazeres
authors.initials: DD
authors.lastname: Rodrigues
authors.affiliation: Department of Biological Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Guisla
authors.initials: G
authors.lastname: Boehs
authors.affiliation: Graduation Program in Animal Science, Santa Cruz State University, Ilhéus, Bahia, Brazil.|Department of Biological Sciences, Santa Cruz State University, Ilhéus, Bahia, Brazil.
authors.forename: Bianca Mendes
authors.initials: BM
authors.lastname: Maciel
mesh_terms: D000818:Animals; D049896:Crassostrea / Q000382:microbiology*; D004926:Escherichia coli / Q000302:isolation & purification; D006801:Humans; D015995:Prevalence; D001618:beta-Lactamases; D047090:beta-Lactams
chemical_list: D047090:beta-Lactams; D001618:beta-Lactamases
keywords: Microbiological quality control; Oyster culture; Quantitative PCR; blaTEM