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Yi S, Song H, Kim WH, Lee S, Guk JH, Woo J, Cho S. Dynamics of microbiota and antimicrobial resistance in on-farm dairy processing plants using metagenomic and culture-dependent approaches. Int J Food Microbiol 2024; 417:110704. [PMID: 38640816 DOI: 10.1016/j.ijfoodmicro.2024.110704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/22/2024] [Accepted: 04/12/2024] [Indexed: 04/21/2024]
Abstract
On-farm dairy processing plants, which are situated close to farms and larger dairy processing facilities, face unique challenges in maintaining environmental hygiene. This can impact various stages of dairy processing. These plants operate on smaller scales and use Low-Temperature-Long-Time (LTLT) pasteurization, making them more susceptible to microbial contamination through direct and indirect contact. Antimicrobial-resistant bacteria found on dairy farms pose risks to human health by potentially transferring resistance via dairy products. Our study aimed to investigate microbial distribution and antimicrobial resistance at four key stages: the farm, pre-pasteurization, post-pasteurization, and processing environments. We assessed microbial distribution by quantifying indicator bacteria and conducting metagenomic analysis. Antimicrobial resistance was examined by identifying resistance phenotypes and detecting resistance genes in bacterial isolates and metagenomes. Our results showed that the indicator bacteria were detected at all stages of on-farm dairy processing. We observed a significant reduction in aerobic microbes and coliforms post-pasteurization. However, contamination of the final dairy products increased, suggesting potential cross-contamination during post-pasteurization. Metagenomic analysis revealed that Pseudomonas, a representative psychrotrophic bacterium, was predominant in both the farm (24.1 %) and pre-pasteurization (65.9 %) stages, indicating microbial transfer from the farms to the processing plants. Post-pasteurization, Pseudomonas and other psychrotrophs like Acinetobacter and Enterobacteriaceae remained dominant. Core microbiota analysis identified 74 genera in total, including 13 psychrotrophic bacteria, across all stages. Of the 59 strains isolated from these plants, 49 were psychrotrophic. Antimicrobial resistance analysis showed that 74.6 % (44/59) of isolates were resistant to at least one antibiotic, with cefoxitin-, ampicillin-, amoxicillin-, and ticarcillin-resistant bacteria present at all stages. Identical antimicrobial resistance patterns were observed in isolates from serial stages of the same farm and season, suggesting bacterial transmission across stages. Additionally, 27.1 % (16/59) of isolates carried plasmid-mediated resistance genes, which were also detected in the metagenomes of non-isolated samples, indicating potential antimicrobial resistance gene transmission and their presence in uncultured bacteria. These findings reveal the persistence of antimicrobial-resistant psychrotrophic bacteria in on-farm dairy processing plants, which pose potential health risks via dairy consumption. Our study underscores the importance of both culture-dependent and culture-independent methods to fully understand their distribution and impact.
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Affiliation(s)
- Saehah Yi
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Hyokeun Song
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Woo-Hyun Kim
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Soomin Lee
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Jae-Ho Guk
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - JungHa Woo
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea
| | - Seongbeom Cho
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, South Korea.
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Winters AD, Romero R, Greenberg JM, Galaz J, Shaffer ZD, Garcia-Flores V, Kracht DJ, Gomez-Lopez N, Theis KR. Does the Amniotic Fluid of Mice Contain a Viable Microbiota? Front Immunol 2022; 13:820366. [PMID: 35296083 PMCID: PMC8920496 DOI: 10.3389/fimmu.2022.820366] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/03/2022] [Indexed: 11/13/2022] Open
Abstract
The existence of an amniotic fluid microbiota (i.e., a viable microbial community) in mammals is controversial. Its existence would require a fundamental reconsideration of fetal in utero exposure to and colonization by microorganisms and the role of intra-amniotic microorganisms in fetal immune development as well as in pregnancy outcomes. In this study, we determined whether the amniotic fluid of mice harbors a microbiota in late gestation. The profiles of the amniotic fluids of pups located proximally or distally to the cervix were characterized through quantitative real-time PCR, 16S rRNA gene sequencing, and culture (N = 21 dams). These profiles were compared to those of technical controls for bacterial and DNA contamination. The load of 16S rRNA genes in the amniotic fluid exceeded that in controls. Additionally, the 16S rRNA gene profiles of the amniotic fluid differed from those of controls, with Corynebacterium tuberculostearicum being differentially more abundant in amniotic fluid profiles; however, this bacterium was not cultured from amniotic fluid. Of the 42 attempted bacterial cultures of amniotic fluids, only one yielded bacterial growth – Lactobacillus murinus. The 16S rRNA gene of this common murine-associated bacterium was not detected in any amniotic fluid sample, suggesting it did not originate from the amniotic fluid. No differences in the 16S rRNA gene load, 16S rRNA gene profile, or bacterial culture were observed between the amniotic fluids located Proximally and distally to the cervix. Collectively, these data indicate that, although there is a modest DNA signal of bacteria in murine amniotic fluid, there is no evidence that this signal represents a viable microbiota. While this means that amniotic fluid is not a source of microorganisms for in utero colonization in mice, it may nevertheless contribute to fetal exposure to microbial components. The developmental consequences of this observation warrant further investigation.
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Affiliation(s)
- Andrew D. Winters
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Perinatal Research Initiative in Maternal, Perinatal and Child Health, Wayne State University School of Medicine, Detroit, MI, United States
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Roberto Romero
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI, United States
- Department of Epidemiology and Biostatistics, Michigan State University, East Lansing, MI, United States
- Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI, United States
- Detroit Medical Center, Detroit, MI, United States
| | - Jonathan M. Greenberg
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Jose Galaz
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Zachary D. Shaffer
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, United States
- MD/PhD Combined Degree Program, Wayne State University School of Medicine, Detroit, MI, United States
| | - Valeria Garcia-Flores
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
| | - David J. Kracht
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Nardhy Gomez-Lopez
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Perinatal Research Initiative in Maternal, Perinatal and Child Health, Wayne State University School of Medicine, Detroit, MI, United States
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
- *Correspondence: Kevin R. Theis, ; Nardhy Gomez-Lopez,
| | - Kevin R. Theis
- Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services, Detroit, MI, United States
- Perinatal Research Initiative in Maternal, Perinatal and Child Health, Wayne State University School of Medicine, Detroit, MI, United States
- Department of Biochemistry, Microbiology, and Immunology, Wayne State University School of Medicine, Detroit, MI, United States
- Department of Obstetrics and Gynecology, Wayne State University School of Medicine, Detroit, MI, United States
- *Correspondence: Kevin R. Theis, ; Nardhy Gomez-Lopez,
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